WorldWideScience

Sample records for fusion hohlraum plasmas

  1. Effect of Laser-Plasma Interactions on Inertial Confinement Fusion Hohlraum Dynamics

    CERN Document Server

    Strozzi, D J; Michel, P; Divol, L; Sepke, S M; Kerbel, G D; Thomas, C A; Ralph, J E; Moody, J D; Schneider, M B

    2016-01-01

    The effects of laser-plasma interactions (LPI) on the dynamics of inertial confinement fusion hohlraums is investigated via a new approach that self-consistently couples reduced LPI models into radiation-hydrodynamics numerical codes. The interplay between hydrodynamics and LPI - specifically stimulated Raman scattering (SRS) and crossed-beam energy transfer (CBET) - mostly occurs via momentum and energy deposition into Langmuir and ion acoustic waves. This spatially redistributes energy coupling to the target, which affects the background plasma conditions and thus modifies the laser propagation. This model shows a reduction of CBET, and significant laser energy depletion by Langmuir waves, which reduce the discrepancy between modeling and data from hohlraum experiments on wall x-ray emission and capsule implosion shape.

  2. Laser Plasma Coupling for High Temperature Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Kruer, W.

    1999-11-04

    Simple scaling models indicate that quite high radiation temperatures can be achieved in hohlraums driven with the National Ignition Facility. A scaling estimate for the radiation temperature versus pulse duration for different size NIF hohlraums is shown in Figure 1. Note that a radiation temperature of about 650 ev is projected for a so-called scale 1 hohlraum (length 2.6mm, diameter 1.6mm). With such high temperature hohlraums, for example, opacity experiments could be carried out using more relevant high Z materials rather than low Z surrogates. These projections of high temperature hohlraums are uncertain, since the scaling model does not allow for the very strongly-driven laser plasma coupling physics. Lasnex calculations have been carried out to estimate the plasma and irradiation conditions in a scale 1 hohlraum driven by NIF. Linear instability gains as high as exp(100) have been found for stimulated Brillouin scattering, and other laser-driven instabilities are also far above their thresholds. More understanding of the very strongly-driven coupling physics is clearly needed in order to more realistically assess and improve the prospects for high temperature hohlraums. Not surprisingly, this regime has been avoided for inertial fusion applications and so is relatively unexplored.

  3. A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

    CERN Document Server

    Kuang, Longyu; Jing, Longfei; Lin, Zhiwei; Zhang, Lu; Li, Lilin; Ding, Yongkun; Jiang, Shaoen; Liu, Jie; Zheng, Jian

    2016-01-01

    A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named as three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is made of three cylindrical hohlraums orthogonally jointed. Laser beams are injected through every entrance hole with the same incident angle of 55{\\deg}. The view-factor simulation result shows that the time-varying drive asymmetry of TACH is no more than 1.0% in the whole drive pulse period without any supplementary technology such as beam phasing etc. Its coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, the proposed hohlraum provides a competitive candidate for ignition hohlraum.

  4. A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

    Science.gov (United States)

    Kuang, Longyu; Li, Hang; Jing, Longfei; Lin, Zhiwei; Zhang, Lu; Li, Liling; Ding, Yongkun; Jiang, Shaoen; Liu, Jie; Zheng, Jian

    2016-01-01

    A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is orthogonally jointed of three cylindrical hohlraums. Laser beams are injected through every entrance hole with the same incident angle of 55°. A view-factor simulation result shows that the time-varying drive asymmetry of TACH is less than 1.0% in the whole drive pulse period without any supplementary technology. Coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to that of typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, TACH combines most advantages of various hohlraums and has little predictable risk, providing an important competitive candidate for ignition hohlraum. PMID:27703250

  5. Green frequency-doubled laser-beam propagation in high-temperature hohlraum plasmas.

    Science.gov (United States)

    Niemann, C; Berger, R L; Divol, L; Froula, D H; Jones, O; Kirkwood, R K; Meezan, N; Moody, J D; Ross, J; Sorce, C; Suter, L J; Glenzer, S H

    2008-02-01

    We demonstrate propagation and small backscatter losses of a frequency-doubled (2omega) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of 2 higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2omega laser-beam transmission approaching 80% with simultaneous backscattering losses of less than 10%. These findings suggest that good laser coupling into fusion hohlraums using 2omega light is possible.

  6. Laser-plasma interactions in large gas-filled hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Turner, R.E.; Powers, L.V.; Berger, R.L. [and others

    1996-06-01

    Indirect-drive targets planned for the National Ignition Facility (NIF) laser consist of spherical fuel capsules enclosed in cylindrical Au hohlraums. Laser beams, arranged in cylindrical rings, heat the inside of the Au wall to produce x rays that in turn heat and implode the capsule to produce fusion conditions in the fuel. Detailed calculations show that adequate implosion symmetry can be maintained by filling the hohlraum interior with low-density, low-Z gases. The plasma produced from the heated gas provides sufficient pressure to keep the radiating Au surface from expanding excessively. As the laser heats this gas, the gas becomes a relatively uniform plasma with small gradients in velocity and density. Such long-scale-length plasmas can be ideal mediums for stimulated Brillouin Scattering (SBS). SBS can reflect a large fraction of the incident laser light before it is absorbed by the hohlraum; therefore, it is undesirable in an inertial confinement fusion target. To examine the importance of SBS in NIF targets, the authors used Nova to measure SBS from hohlraums with plasma conditions similar to those predicted for high-gain NIF targets. The plasmas differ from the more familiar exploding foil or solid targets as follows: they are hot (3 keV); they have high electron densities (n{sub e}=10{sup 21}cm{sup {minus}3}); and they are nearly stationary, confined within an Au cylinder, and uniform over large distances (>2 mm). These hohlraums have <3% peak SBS backscatter for an interaction beam with intensities of 1-4 x 10{sup 15} W/cm{sup 2}, a laser wavelength of 0.351{micro}m, f/4 or f/8 focusing optics, and a variety of beam smoothing implementations. Based on these conditions the authors conclude that SBS does not appear to be a problem for NIF targets.

  7. Mitigation of stimulated Raman scattering in hohlraum plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kline, J L; Montgomery, D S; Rose, H A; Goldman, S R [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Froula, D H; Ross, J S [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Stevenson, R M [Atomic Weapons Establishment, Aldermaston, Reading RG7 4PR (United Kingdom); Lushnikov, P M [Department of Mathematics, University of New Mexico, Albuquerque, NM (United States)], E-mail: jkline@lanl.gov

    2008-05-15

    One aspect of recent research to control Stimulated Raman Scattering (SRS) in hohlraum plasmas is the investigation of risk mitigation strategies for indirect drive inertial confinement fusion. Experimental tests of these strategies, based on prior theoretical and experimental knowledge of SRS, are performed in hohlraum experiments. In the last year, two strategies have been investigated. The first is the use of high Z dopants to reduce SRS backscatter. Forward stimulated Brillouin scattering (FSBS) could lead to beam spray reducing SRS. Since FSBS depends on the electron temperature and thermal effects depend strongly on Z{sup 2}, a small amount of a high Z dopant, 1-2%, can have a large effect. Experiments have been conducted at the Omega laser to test this theory by varying the amount of Xe dopant in neo-pentane gas filled hohlraums. The experimental measurements do show a decrease in SRS backscatter as Xe dopant is added. However, there are still uncertainties regarding the responsible mechanism since increases inverse-Bremsstrahlung absorption of the SRS light may play a role. The second strategy investigated is using high k{lambda}{sub D} plasmas to reduce SRS backscatter. Experiments conducted at the Omega laser facility in hohlraum plasmas determined the critical onset intensity for a range of k{lambda}{sub D}. A scaling of the critical onset intensity as a function of k{lambda}{sub D} has been determined.

  8. A new ignition hohlraum design for indirect-drive inertial confinement fusion

    Science.gov (United States)

    Li, Xin; Wu, Chang-Shu; Dai, Zhen-Sheng; Zheng, Wu-Di; Gu, Jian-Fa; Gu, Pei-Jun; Zou, Shi-Yang; Liu, Jie; Zhu, Shao-Ping

    2016-08-01

    In this paper, a six-cylinder-port hohlraum is proposed to provide high symmetry flux on capsule. It is designed to ignite a capsule with 1.2-mm radius in indirect-drive inertial confinement fusion (ICF). Flux symmetry and laser energy are calculated by using three-dimensional view factor method and laser energy balance in hohlraum. Plasma conditions are analyzed based on the two-dimensional radiation-hydrodynamic simulations. There is no Y lm (l ⩽ 4) asymmetry in the six-cylinder-port hohlraum when the influences of laser entrance holes (LEHs) and laser spots cancel each other out with suitable target parameters. A radiation drive with 300 eV and good flux symmetry can be achieved by using a laser energy of 2.3 MJ and peak power of 500 TW. According to the simulations, the electron temperature and the electron density on the wall of laser cone are high and low, respectively, which are similar to those of outer cones in the hohlraums on National Ignition Facility (NIF). And the laser intensity is also as low as those of NIF outer cones. So the backscattering due to laser plasma interaction (LPI) is considered to be negligible. The six-cyliner-port hohlraum could be superior to the traditional cylindrical hohlraum and the octahedral hohlraum in both higher symmetry and lower backscattering without supplementary technology at an acceptable laser energy level. It is undoubted that the hohlraum will add to the diversity of ICF approaches. Project supported by the National Natural Science Foundation of China (Grant Nos. 11435011 and 11575034).

  9. Electron Temperature and Plasma Flow Measurements of NIF Hohlraum Plasmas

    Science.gov (United States)

    Barrios, M. A.; Liedahl, D. A.; Schneider, M. B.; Jones, O.; Brow, G. V.; Regan, S. P.; Fournier, K. B.; Moore, A. S.; Ross, J. S.; Eder, D.; Landen, O.; Kauffman, R. L.; Nikroo, A.; Kroll, J.; Jaquez, J.; Huang, H.; Hansen, S. B.; Callahan, D. A.; Hinkel, D. E.; Bradley, D.; Moody, J. D.; LLNL Collaboration; LLE Collaboration; GA Collaboration; SNL Collaboration

    2016-10-01

    Characterizing the plasma conditions inside NIF hohlraums, in particular mapping the plasma Te, is critical to gaining insight into mechanisms that affect energy coupling and transport in the hohlraum. The dot spectroscopy platform provides a temporal history of the localized Te and plasma flow inside a NIF hohlraum, by introducing a Mn-Co tracer dot, at strategic locations inside the hohlraum, that comes to equilibrium with the local plasma. K-shell X-ray spectroscopy of the tracer dot is recorded onto an absolutely calibrated X-ray streak spectrometer. Isoelectronic and interstage line ratios are used to infer localized Te through comparison with atomic physics calculations using SCRAM. Time resolved X-ray images are simultaneously taken of the expanding dot, providing plasma (ion) flow information. We present recent results provided by this platform and compare with simulations using HYDRA. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  10. Characterizing Hohlraum Plasma Conditions at the National Ignition Facility (NIF) Using X-ray Spectroscopy

    Science.gov (United States)

    Barrios, Maria Alejandra

    2015-11-01

    Improved hohlraums will have a significant impact on increasing the likelihood of indirect drive ignition at the NIF. In indirect-drive Inertial Confinement Fusion (ICF), a high-Z hohlraum converts laser power into a tailored x-ray flux that drives the implosion of a spherical capsule filled with D-T fuel. The x-radiation drive to capsule coupling sets the velocity, adiabat, and symmetry of the implosion. Previous experiments in gas-filled hohlraums determined that the laser-hohlraum energy coupling is 20-25% less than modeled, therefore identifying energy loss mechanisms that reduce the efficacy of the hohlraum drive is central to improving implosion performance. Characterizing the plasma conditions, particularly the plasma electron temperature (Te) , is critical to understanding mechanism that affect the energy coupling such as the laser plasma interactions (LPI), hohlraum x-ray conversion efficiency, and dynamic drive symmetry. The first Te measurements inside a NIF hohlraum, presented here, were achieved using K-shell X-ray spectroscopy of an Mn-Co tracer dot. The dot is deposited on a thin-walled CH capsule, centered on the hohlraum symmetry axis below the laser entrance hole (LEH) of a bottom-truncated hohlraum. The hohlraum x-ray drive ablates the dot and causes it to flow upward, towards the LEH, entering the hot laser deposition region. An absolutely calibrated streaked spectrometer with a line of sight into the LEH records the temporal history of the Mn and Co X-ray emission. The measured (interstage) Lyα/ Heα line ratios for Co and Mn and the Mn-Heα/Co-Heα isoelectronic line ratio are used to infer the local plasma Te from the atomic physics code SCRAM. Time resovled x-ray images perpendicular to the hohlraum axis record the dot expansion and trajectory into the LEH region. The temporal evolution of the measured Te and dot trajectory are compared with simulations from radiation-hydrodynamic codes. This work was performed under the auspices of the U

  11. A new ignition hohlraum design for indirect-drive inertial confinement fusion

    CERN Document Server

    Xin, Li; Zhensheng, Dai; Wudi, Zheng; Jianfa, Gu; Peijun, Gu; Shiyang, Zou; Jie, Liu; Shaoping, Zhu

    2016-01-01

    In this paper, a six-cylinder-port hohlraum is proposed to provide high symmetry flux on capsule. It is designed to ignite a capsule with 1.2 mm radius in indirect-drive inertial confinement fusion (ICF) . Flux symmetry and laser energy are calculated by using three dimensional view factor method and laser energy balance in hohlraums. Plasma conditions are analyzed based on the two dimensional radiation-hydrodynamic simulations. There is no Ylm (l<=4) asymmetry in the six-cylinder-port hohlraum when the influences of laser entrance holes (LEHs) and laser spots cancel each other out with suitable target parameters. A radiation drive with 300 eV and good flux symmetry can be achieved with use of laser energy of 2.3 MJ and 500 TW peak power. According to the simulations, the electron temperature and the electron density on the wall of laser cone are high and low, respectively, which are similar to those of outer cones in the hohlraums on National Ignition Facility (NIF). And the laser intensity is also as low...

  12. Laser plasma interaction in rugby-shaped hohlraums

    Science.gov (United States)

    Masson-Laborde, P.-E.; Philippe, F.; Tassin, V.; Monteil, M.-C.; Gauthier, P.; Casner, A.; Depierreux, S.; Seytor, P.; Teychenne, D.; Loiseau, P.; Freymerie, P.

    2014-10-01

    Rugby shaped-hohlraum has proven to give high performance compared to a classical similar-diameter cylinder hohlraum. Due to this performance, this hohlraum has been chosen as baseline ignition target for the Laser MegaJoule (LMJ). Many experiments have therefore been performed during the last years on the Omega laser facility in order to study in details the rugby hohlraum. In this talk, we will discuss the interpretation of these experiments from the point of view of the laser plasma instability problem. Experimental comparisons have been done between rugby, cylinder and elliptical shape rugby hohlraums and we will discuss how the geometry differences will affect the evolution of laser plasma instabilities (LPI). The efficiency of laser smoothing techniques on these instabilities will also be discussed as well as gas filling effect. The experimental results will be compared with FCI2 hydroradiative calculations and linear postprocessing with Piranah. Experimental Raman and Brillouin spectrum, from which we can infer the location of the parametric instabilities, will be compared to simulated ones, and will give the possibility to compare LPI between the different hohlraum geometries.

  13. Structure and dynamics of plasma interfaces in laser-driven hohlraums

    Science.gov (United States)

    Li, C. K.; Sio, H.; Frenje, J. A.; Séguin, F. H.; Birkel, A.; Petrasso, R. D.; Wilks, S. C.; Amendt, P. A.; Remington, B. A.; Masson-Laborde, P.-E.; Laffite, S.; Tassin, V.; Betti, R.; Sanster, T. C.; Fitzsimmons, P.; Farrell, M.

    2016-10-01

    Understanding the structure and dynamics of plasma interfaces in laser-driven hohlraums is important because of their potential effects on capsule implosion dynamics. To that end, a series of experiments was performed to explore critical aspects of the hohlraum environment, with particular emphasis on the role of self-generated spontaneous electric and magnetic fields at plasma interfaces, including the interface between fill-gas and Au-blowoff. The charged fusion products (3-MeV DD protons and 14.7-MeV D3He protons generated in shock-driven, D3He filled backlighter capsule) pass through the subject hohlraum and form images on CR-39 nuclear track detectors, providing critical information. Important physics topics, including ion diffusive mix and Rayleigh-Taylor instabilities, will be studied to illuminate ion kinetic dynamics and hydrodynamic instability at plasma interfaces in laser-driven hohlraums. This work was supported in part by LLE, the U.S. DoE (NNSA, NLUF) and LLNL.

  14. Interaction of high power laser beams with plasma in ICF hohlraum using the FDTD method

    Science.gov (United States)

    Lin, Zhili

    2016-11-01

    In the indirect-drive Inertial confinement fusion (ICF) system, groups of laser beams are injected into a gold cylindrical hohlraum and plasma is stimulated with the ablation of the wall of hohlraum by the laser beams. In our work, the finite-difference time-domain (FDTD) method associated with the bilinear transform and Maclaurin series expansion approaches is utilized to examine the laser beam propagation in plasma described by the Drude model. The state-of-the-art approaches for generating the laser beams are presented and realized according to the full utilization of the TF/SF source condition. Base on the previous technologies, the quantitatively numerical analysis of the propagation characteristics of laser beams in the plasma is conducted. The obtained results are illustrated and discussed that are helpful for the parameter optimization of laser beams for an ICF system.

  15. Laser plasma interaction on rugby hohlraum on the Omega Laser Facility: Comparisons between cylinder, rugby, and elliptical hohlraums

    Science.gov (United States)

    Masson-Laborde, P. E.; Monteil, M. C.; Tassin, V.; Philippe, F.; Gauthier, P.; Casner, A.; Depierreux, S.; Neuville, C.; Villette, B.; Laffite, S.; Seytor, P.; Fremerye, P.; Seka, W.; Teychenné, D.; Debayle, A.; Marion, D.; Loiseau, P.; Casanova, M.

    2016-02-01

    Gas-filled rugby-shaped hohlraums have demonstrated high performances compared to a classical similar diameter cylinder hohlraum with a nearly 40% increase of x-ray drive, 10% higher measured peak drive temperature, and an increase in neutron production. Experimental comparisons have been done between rugby, cylinder, and elliptical hohlraums. The impact of these geometry differences on the laser plasma instabilities is examined. Using comparisons with hydrodynamic simulations carried out with the code FCI2 and postprocessed by Piranah, we have been able to reproduce the stimulated Raman and Brillouin scattering spectrum of the different beams. Using a methodology based on a statistical analysis for the gain calculations, we show that the behavior of the laser plasma instabilities in rugby hohlraums can be reproduced. The efficiency of laser smoothing techniques to mitigate these instabilities are discussed, and we show that while rugby hohlraums exhibit more laser plasma instabilities than cylinder hohlraum, the latter can be mitigated in the case of an elliptical hohlraum.

  16. Novel free-form hohlraum shape design and optimization for laser-driven inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shaoen; Jing, Longfei, E-mail: scmyking-2008@163.com; Ding, Yongkun [Laser Fusion Research Center, China Academy Engineering Physics, Mianyang 621900 (China); Huang, Yunbao, E-mail: huangyblhy@gmail.com [Mechatronics School of Guangdong University of Technology, Guangzhou 510006 (China)

    2014-10-15

    The hohlraum shape attracts considerable attention because there is no successful ignition method for laser-driven inertial confinement fusion at the National Ignition Facility. The available hohlraums are typically designed with simple conic curves, including ellipses, parabolas, arcs, or Lame curves, which allow only a few design parameters for the shape optimization, making it difficult to improve the performance, e.g., the energy coupling efficiency or radiation drive symmetry. A novel free-form hohlraum design and optimization approach based on the non-uniform rational basis spline (NURBS) model is proposed. In the present study, (1) all kinds of hohlraum shapes can be uniformly represented using NURBS, which is greatly beneficial for obtaining the optimal available hohlraum shapes, and (2) such free-form uniform representation enables us to obtain an optimal shape over a large design domain for the hohlraum with a more uniform radiation and higher drive temperature of the fuel capsule. Finally, a hohlraum is optimized and evaluated with respect to the drive temperature and symmetry at the Shenguang III laser facility in China. The drive temperature and symmetry results indicate that such a free-form representation is advantageous over available hohlraum shapes because it can substantially expand the shape design domain so as to obtain an optimal hohlraum with high performance.

  17. Demonstration of ignition radiation temperatures in indirect-drive inertial confinement fusion hohlraums.

    Science.gov (United States)

    Glenzer, S H; MacGowan, B J; Meezan, N B; Adams, P A; Alfonso, J B; Alger, E T; Alherz, Z; Alvarez, L F; Alvarez, S S; Amick, P V; Andersson, K S; Andrews, S D; Antonini, G J; Arnold, P A; Atkinson, D P; Auyang, L; Azevedo, S G; Balaoing, B N M; Baltz, J A; Barbosa, F; Bardsley, G W; Barker, D A; Barnes, A I; Baron, A; Beeler, R G; Beeman, B V; Belk, L R; Bell, J C; Bell, P M; Berger, R L; Bergonia, M A; Bernardez, L J; Berzins, L V; Bettenhausen, R C; Bezerides, L; Bhandarkar, S D; Bishop, C L; Bond, E J; Bopp, D R; Borgman, J A; Bower, J R; Bowers, G A; Bowers, M W; Boyle, D T; Bradley, D K; Bragg, J L; Braucht, J; Brinkerhoff, D L; Browning, D F; Brunton, G K; Burkhart, S C; Burns, S R; Burns, K E; Burr, B; Burrows, L M; Butlin, R K; Cahayag, N J; Callahan, D A; Cardinale, P S; Carey, R W; Carlson, J W; Casey, A D; Castro, C; Celeste, J R; Chakicherla, A Y; Chambers, F W; Chan, C; Chandrasekaran, H; Chang, C; Chapman, R F; Charron, K; Chen, Y; Christensen, M J; Churby, A J; Clancy, T J; Cline, B D; Clowdus, L C; Cocherell, D G; Coffield, F E; Cohen, S J; Costa, R L; Cox, J R; Curnow, G M; Dailey, M J; Danforth, P M; Darbee, R; Datte, P S; Davis, J A; Deis, G A; Demaret, R D; Dewald, E L; Di Nicola, P; Di Nicola, J M; Divol, L; Dixit, S; Dobson, D B; Doppner, T; Driscoll, J D; Dugorepec, J; Duncan, J J; Dupuy, P C; Dzenitis, E G; Eckart, M J; Edson, S L; Edwards, G J; Edwards, M J; Edwards, O D; Edwards, P W; Ellefson, J C; Ellerbee, C H; Erbert, G V; Estes, C M; Fabyan, W J; Fallejo, R N; Fedorov, M; Felker, B; Fink, J T; Finney, M D; Finnie, L F; Fischer, M J; Fisher, J M; Fishler, B T; Florio, J W; Forsman, A; Foxworthy, C B; Franks, R M; Frazier, T; Frieder, G; Fung, T; Gawinski, G N; Gibson, C R; Giraldez, E; Glenn, S M; Golick, B P; Gonzales, H; Gonzales, S A; Gonzalez, M J; Griffin, K L; Grippen, J; Gross, S M; Gschweng, P H; Gururangan, G; Gu, K; Haan, S W; Hahn, S R; Haid, B J; Hamblen, J E; Hammel, B A; Hamza, A V; Hardy, D L; Hart, D R; Hartley, R G; Haynam, C A; Heestand, G M; Hermann, M R; Hermes, G L; Hey, D S; Hibbard, R L; Hicks, D G; Hinkel, D E; Hipple, D L; Hitchcock, J D; Hodtwalker, D L; Holder, J P; Hollis, J D; Holtmeier, G M; Huber, S R; Huey, A W; Hulsey, D N; Hunter, S L; Huppler, T R; Hutton, M S; Izumi, N; Jackson, J L; Jackson, M A; Jancaitis, K S; Jedlovec, D R; Johnson, B; Johnson, M C; Johnson, T; Johnston, M P; Jones, O S; Kalantar, D H; Kamperschroer, J H; Kauffman, R L; Keating, G A; Kegelmeyer, L M; Kenitzer, S L; Kimbrough, J R; King, K; Kirkwood, R K; Klingmann, J L; Knittel, K M; Kohut, T R; Koka, K G; Kramer, S W; Krammen, J E; Krauter, K G; Krauter, G W; Krieger, E K; Kroll, J J; La Fortune, K N; Lagin, L J; Lakamsani, V K; Landen, O L; Lane, S W; Langdon, A B; Langer, S H; Lao, N; Larson, D W; Latray, D; Lau, G T; Le Pape, S; Lechleiter, B L; Lee, Y; Lee, T L; Li, J; Liebman, J A; Lindl, J D; Locke, S F; Loey, H K; London, R A; Lopez, F J; Lord, D M; Lowe-Webb, R R; Lown, J G; Ludwigsen, A P; Lum, N W; Lyons, R R; Ma, T; MacKinnon, A J; Magat, M D; Maloy, D T; Malsbury, T N; Markham, G; Marquez, R M; Marsh, A A; Marshall, C D; Marshall, S R; Maslennikov, I L; Mathisen, D G; Mauger, G J; Mauvais, M -Y; McBride, J A; McCarville, T; McCloud, J B; McGrew, A; McHale, B; MacPhee, A G; Meeker, J F; Merill, J S; Mertens, E P; Michel, P A; Miller, M G; Mills, T; Milovich, J L; Miramontes, R; Montesanti, R C; Montoya, M M; Moody, J; Moody, J D; Moreno, K A; Morris, J; Morriston, K M; Nelson, J R; Neto, M; Neumann, J D; Ng, E; Ngo, Q M; Olejniczak, B L; Olson, R E; Orsi, N L; Owens, M W; Padilla, E H; Pannell, T M; Parham, T G; Patterson, R W; Pavel, G; Prasad, R R; Pendlton, D; Penko, F A; Pepmeier, B L; Petersen, D E; Phillips, T W; Pigg, D; Piston, K W; Pletcher, K D; Powell, C L; Radousky, H B; Raimondi, B S; Ralph, J E; Rampke, R L; Reed, R K; Reid, W A; Rekow, V V; Reynolds, J L; Rhodes, J J; Richardson, M J; Rinnert, R J; Riordan, B P; Rivenes, A S; Rivera, A T; Roberts, C J; Robinson, J A; Robinson, R B; Robison, S R; Rodriguez, O R; Rogers, S P; Rosen, M D; Ross, G F; Runkel, M; Runtal, A S; Sacks, R A; Sailors, S F; Salmon, J T; Salmonson, J D; Saunders, R L; Schaffer, J R; Schindler, T M; Schmitt, M J; Schneider, M B; Segraves, K S; Shaw, M J; Sheldrick, M E; Shelton, R T; Shiflett, M K; Shiromizu, S J; Shor, M; Silva, L L; Silva, S A; Skulina, K M; Smauley, D A; Smith, B E; Smith, L K; Solomon, A L; Sommer, S; Soto, J G; Spafford, N I; Speck, D E; Springer, P T; Stadermann, M; Stanley, F; Stone, T G; Stout, E A; Stratton, P L; Strausser, R J; Suter, L J; Sweet, W; Swisher, M F; Tappero, J D; Tassano, J B; Taylor, J S; Tekle, E A; Thai, C; Thomas, C A; Thomas, A; Throop, A L; Tietbohl, G L; Tillman, J M; Town, R P J; Townsend, S L; Tribbey, K L; Trummer, D; Truong, J; Vaher, J; Valadez, M

    2011-02-25

    We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.

  18. Experimental demonstration of low laser-plasma instabilities in gas-filled spherical hohlraums at laser injection angle designed for ignition target

    Science.gov (United States)

    Lan, Ke; Li, Zhichao; Xie, Xufei; Chen, Yao-Hua; Zheng, Chunyang; Zhai, Chuanlei; Hao, Liang; Yang, Dong; Huo, Wen Yi; Ren, Guoli; Peng, Xiaoshi; Xu, Tao; Li, Yulong; Li, Sanwei; Yang, Zhiwen; Guo, Liang; Hou, Lifei; Liu, Yonggang; Wei, Huiyue; Liu, Xiangming; Cha, Weiyi; Jiang, Xiaohua; Mei, Yu; Li, Yukun; Deng, Keli; Yuan, Zheng; Zhan, Xiayu; Zhang, Haijun; Jiang, Baibin; Zhang, Wei; Deng, Xuewei; Liu, Jie; Du, Kai; Ding, Yongkun; Wei, Xiaofeng; Zheng, Wanguo; Chen, Xiaodong; Campbell, E. M.; He, Xian-Tu

    2017-03-01

    Octahedral spherical hohlraums with a single laser ring at an injection angle of 55∘ are attractive concepts for laser indirect drive due to the potential for achieving the x-ray drive symmetry required for high convergence implosions. Laser-plasma instabilities, however, are a concern given the long laser propagation path in such hohlraums. Significant stimulated Raman scattering has been observed in cylindrical hohlraums with similar laser propagation paths during the ignition campaign on the National Ignition Facility (NIF). In this Rapid Communication, experiments demonstrating low levels of laser-driven plasma instability (LPI) in spherical hohlraums with a laser injection angle of 55∘ are reported and compared to that observed with cylindrical hohlraums with injection angles of 28 .5∘ and 55∘, similar to that of the NIF. Significant LPI is observed with the laser injection of 28 .5∘ in the cylindrical hohlraum where the propagation path is similar to the 55∘ injection angle for the spherical hohlraum. The experiments are performed on the SGIII laser facility with a total 0.35 -μ m incident energy of 93 kJ in a 3 nsec pulse. These experiments demonstrate the role of hohlraum geometry in LPI and demonstrate the need for systematic experiments for choosing the optimal configuration for ignition studies with indirect drive inertial confinement fusion.

  19. Experimental demonstration of low laser-plasma instabilities in gas-filled spherical hohlraums at laser injection angle designed for ignition target.

    Science.gov (United States)

    Lan, Ke; Li, Zhichao; Xie, Xufei; Chen, Yao-Hua; Zheng, Chunyang; Zhai, Chuanlei; Hao, Liang; Yang, Dong; Huo, Wen Yi; Ren, Guoli; Peng, Xiaoshi; Xu, Tao; Li, Yulong; Li, Sanwei; Yang, Zhiwen; Guo, Liang; Hou, Lifei; Liu, Yonggang; Wei, Huiyue; Liu, Xiangming; Cha, Weiyi; Jiang, Xiaohua; Mei, Yu; Li, Yukun; Deng, Keli; Yuan, Zheng; Zhan, Xiayu; Zhang, Haijun; Jiang, Baibin; Zhang, Wei; Deng, Xuewei; Liu, Jie; Du, Kai; Ding, Yongkun; Wei, Xiaofeng; Zheng, Wanguo; Chen, Xiaodong; Campbell, E M; He, Xian-Tu

    2017-03-01

    Octahedral spherical hohlraums with a single laser ring at an injection angle of 55^{∘} are attractive concepts for laser indirect drive due to the potential for achieving the x-ray drive symmetry required for high convergence implosions. Laser-plasma instabilities, however, are a concern given the long laser propagation path in such hohlraums. Significant stimulated Raman scattering has been observed in cylindrical hohlraums with similar laser propagation paths during the ignition campaign on the National Ignition Facility (NIF). In this Rapid Communication, experiments demonstrating low levels of laser-driven plasma instability (LPI) in spherical hohlraums with a laser injection angle of 55^{∘} are reported and compared to that observed with cylindrical hohlraums with injection angles of 28.5^{∘} and 55^{∘}, similar to that of the NIF. Significant LPI is observed with the laser injection of 28.5^{∘} in the cylindrical hohlraum where the propagation path is similar to the 55^{∘} injection angle for the spherical hohlraum. The experiments are performed on the SGIII laser facility with a total 0.35-μm incident energy of 93 kJ in a 3 nsec pulse. These experiments demonstrate the role of hohlraum geometry in LPI and demonstrate the need for systematic experiments for choosing the optimal configuration for ignition studies with indirect drive inertial confinement fusion.

  20. Preliminary study on a tetrahedral hohlraum with four half-cylindrical cavities for indirectly driven inertial confinement fusion

    Science.gov (United States)

    Jing, Longfei; Jiang, Shaoen; Kuang, Longyu; Zhang, Lu; Li, Liling; Lin, Zhiwei; Li, Hang; Zheng, Jianhua; Hu, Feng; Huang, Yunbao; Huang, Tianxuan; Ding, Yongkun

    2017-04-01

    A tetrahedral hohlraum with four half-cylindrical cavities (FHCH) is proposed to balance tradeoffs among the drive symmetry, coupling efficiency, and plasma filling of the hohlraum performance for indirectly driven inertial confinement fusion. The peak drive symmetry in the FHCH with a cavity-to-capsule ratio (CCR) of 2.2 is comparable to those in the spherical hohlraum of CCR  =  4.5 with six laser entrance holes (6LEHs-Sph.) ((Lan et al 2014 Phys. Plasmas 21 010704) and three-axis cylindrical hohlraum (6LEHs-Cyls.) of CCR  =  2.0 (Kuang et al 2016 Sci. Rep. 6 34636), and the filling time of plasma is close to the ones in the 6LEHs-Cyls. and the ignition target Rev5-CH of the national ignition campaign, and about half of that in the 6LEHs-Sph. In particular, the coupling efficiency is about 19% and 16% higher than those of the 6LEHs-Sph. and 6LEHs-Cyls., respectively. Besides, preliminary study indicates that the FHCH has a robust symmetry to uncertainties of power imbalance and pointing errors of laser beams. Furthermore, utilizing the FHCH, the feasibility of a tetrahedral indirect drive approach on the national ignition facility and hybrid indirect–direct drive approach with the laser arrangement designed specially for 6LEHs-Sph. or 6LEHs-Cyls., is also envisioned. Therefore, the proposed hohlraum configuration merits consideration as an alternative route to indirect-drive ignition.

  1. Laser-plasma interactions and implosion symmetry in rugby hohlraums

    Science.gov (United States)

    Michel, Pierre; Berger, R. L.; Lasinski, B. F.; Ross, J. S.; Divol, L.; Williams, E. A.; Meeker, D.; Langdon, B. A.; Park, H.; Amendt, P.

    2011-10-01

    Cross-beam energy transfer is studied in the context of ``rugby''-hohlraum experiments at the Omega laser facility in FY11, in preparation for future NIF experiments. The transfer acts in opposite direction between rugby and cylinder hohlraums due to the different beam pointing geometries and flow patterns. Its interaction with backscatter is also different as both happen in similar regions inside rugby hohlraums. We will analyze the effects of non-linearities and temporal beam smoothing on energy transfer using the code pF3d. Calculations will be compared to experiments at Omega; analysis of future rugby hohlraum experiments on NIF will also be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. Fusion plasma physics

    CERN Document Server

    Stacey, Weston M

    2012-01-01

    This revised and enlarged second edition of the popular textbook and reference contains comprehensive treatments of both the established foundations of magnetic fusion plasma physics and of the newly developing areas of active research. It concludes with a look ahead to fusion power reactors of the future. The well-established topics of fusion plasma physics -- basic plasma phenomena, Coulomb scattering, drifts of charged particles in magnetic and electric fields, plasma confinement by magnetic fields, kinetic and fluid collective plasma theories, plasma equilibria and flux surface geometry, plasma waves and instabilities, classical and neoclassical transport, plasma-materials interactions, radiation, etc. -- are fully developed from first principles through to the computational models employed in modern plasma physics. The new and emerging topics of fusion plasma physics research -- fluctuation-driven plasma transport and gyrokinetic/gyrofluid computational methodology, the physics of the divertor, neutral ...

  3. 2D simulations of hohlraum targets for laser-plasma experiments and ion stopping measurement in hot plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Basko, M.M. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany). ExtreMe Matter Institute EMMI; Maruhn, J.; Tauschwitz, Anna [Frankfurt Univ. (Germany); Novikov, V.G.; Grushin, A.S. [Keldysh Institute of Applied Mathematics, Moscow (Russian Federation)

    2011-12-15

    An attractive way to create uniform plasma states at high temperatures and densities is by using hohlraums - cavities with heavy-metal walls that are either directly or indirectly heated by intense laser pulses to x-ray temperatures of tens and hundreds electron volts. A sample material, whose plasma state is to be studied, can be placed inside such a hohlraum (usually in the form of a low-density foam) and uniformly heated to a high temperature. In this case a high-Z hohlraum enclosure serves a double purpose: it prevents the hot plasma from rapid disassembly due to hydrodynamic expansion and, at the same time, suppresses its rapid radiative cooling by providing high diffusive resistivity for X-rays. Of course, both the inertial and the thermal confinement of high-temperature plasmas can be achieved only for a limited period of time - on the order of nanoseconds for millimeter-scale hohlraums. Some time ago such hohlraum targets were proposed for measurements of the stopping power of hot dense plasmas for fast ions at GSI (Darmstadt). Theoretical modeling of hohlraum targets has always been a challenging task for computational physics because it should combine multidimensional hydrodynamic simulations with the solution of the spectral transfer equation for thermal radiation. In this work we report on our latest progress in this direction, namely, we present the results of 2D (two-dimensional) simulations with a newly developed radiation-hydrodynamics code RALEF-2D of two types of the hohlraum targets proposed for experiments on the PHELIX laser at GSI. The first configuration is a simple spherical hohlraum with gold walls and empty interior, which has two holes - one for laser beam entrance, and the other for diagnostics. The hohlraums of this type have already been used in several experimental sessions with the NHELIX and PHELIX lasers at GSI. The second type is a two-chamber cylindrical hohlraum with a characteristic {omega}-shaped cross-section of the enclosure

  4. Simulation of self-generated magnetic fields in an inertial fusion hohlraum environment

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, W. A.; Koning, J. M.; Strozzi, D. J.; Hinkel, D. E.; Berzak Hopkins, L. F.; Jones, O. S.; Rosen, M. D.

    2017-05-01

    We present radiation-hydrodynamic simulations of self-generated magnetic field in a hohlraum, which show an increased temperature in large regions of the underdense fill. Non-parallel gradients in electron density and temperature in a laser-heated plasma give rise to a self-generated field by the “Biermann battery” mechanism. Here, HYDRA simulations of three hohlraum designs on the National Ignition Facility are reported, which use a partial magnetohydrodynamic (MHD) description that includes the self-generated source term, resistive dissipation, and advection of the field due to both the plasma flow and the Nernst term. Anisotropic electron heat conduction parallel and perpendicular to the field is included, but not the Righi-Leduc heat flux. The field strength is too small to compete significantly with plasma pressure, but affects plasma conditions by reducing electron heat conduction perpendicular to the field. Significant reductions in heat flux can occur, especially for high Z plasma, at modest values of the Hall parameter, Ωeτei≲1Ωeτei≲1, where Ωe=eB/mecΩe=eB/mec and τei is the electron-ion collision time. The inclusion of MHD in the simulations leads to 1 keV hotter electron temperatures in the laser entrance hole and high-Z wall blowoff, which reduces inverse-bremsstrahlung absorption of the laser beam. This improves propagation of the inner beams pointed at the hohlraum equator, resulting in a symmetry shift of the resulting capsule implosion towards a more prolate shape. The time of peak x-ray production in the capsule shifts later by only 70 ps (within experimental uncertainty), but a decomposition of the hotspot shape into Legendre moments indicates a shift of P2/P0P2/P0 by ~20%. This indicates that MHD cannot explain why simulated x-ray drive exceeds measured levels, but may be partially responsible for failures to correctly model the symmetry.

  5. High flux symmetry of the Spherical Hohlraum with Octahedral 6LEHs at a Golden Hohlraum-to-capsule Radius ratio

    CERN Document Server

    Lan, Ke; Lai, Dongxian; Zheng, Wudi; He, Xian-Tu

    2013-01-01

    In the present Letter, we advocate a spherical hohlraums with octahedral six laser entrance holes (LEHs) for inertial fusion, which has advantages over the conventional hohlraums of cylindrical geometry since it contains only one cone at each LEH and the problems caused by the beam overlap and crossed-beam energy transfer can be eliminated and the energy coupling efficiency will be enhanced. In particular, our analytical theory predicts that at a specific hohlraum-to-capsule radius ratio, i.e., the golden ratio, the flux asymmetry on the shell of capsule can be significantly reduced. This analytic prediction has been certified by numerical calculations with view factor model. The proposed octahedral hohlraum is also flexible and can be applicable to diverse inertial fusion drive approaches such as indirect and hybrid indirect-direct drives. As an application, we design an ignition octahedral hohlraum for the hybrid drive by using the expended plasma-filling model and view factor model.

  6. Review of the three candidate hohlraums in ICF

    CERN Document Server

    Li, Xin; Dai, Zhensheng; Zheng, Wudi; Zhao, Yiqing; Zhang, Huasen; Gu, Jianfa; Kang, Dongguo; Ge, Fengjun; Gu, Peijun; Zou, Shiyang

    2016-01-01

    In this paper, we give a review of three hohlraum geometries, including cylindrical, octahedral and six-cylinder-port hohlraums, in inertial confinement fusion (ICF) mainly from theoretical side. Every hohlraum has its own strengths and weaknesses. Although there is a problem of drive asymmetry in the cylindrical hohlraums due to some non-ideal factors, the success of ignition is still possible if more laser energy is available beyond the US National Ignition Facility (NIF) in the future. Octahedral hohlraums can provide the high symmetry flux on capsule. However, octahedral hohlraums suffer from several problems due to the complicated three-dimensional plasma conditions inside. And up to now, there is no one target design with the octahedral hohlraums in which each problem can be solved at the same time. Six-cylinder-port hohlraums combine the merits in theory of both cylindrical and octahedral hohlraums to a certain extent. We introduce a target design with good performance by using the six-cylinder-port ho...

  7. Imposed magnetic field and hot electron propagation in inertial fusion hohlraums

    Science.gov (United States)

    Strozzi, David J.; Perkins, L. J.; Marinak, M. M.; Larson, D. J.; Koning, J. M.; Logan, B. G.

    2015-12-01

    > . The field's main hydrodynamic effect is to significantly reduce electron thermal conduction perpendicular to the field. This results in hotter and less dense plasma on the equator between the capsule and hohlraum wall. The inner laser beams experience less inverse bremsstrahlung absorption before reaching the wall. The X-ray drive is thus stronger from the equator with the imposed field. We study superthermal, or `hot', electron dynamics with the particle-in-cell code ZUMA, using plasma conditions from HYDRA. During the early-time laser picket, hot electrons based on two-plasmon decay in the laser entrance hole (Regan et al., Phys. Plasmas, vol. 17(2), 2010, 020703) are guided to the capsule by a 70 T field. Twelve times more energy deposits in the deuterium-tritium fuel. For plasma conditions early in peak laser power, we present mono-energetic test-case studies with ZUMA as well as sources based on inner-beam stimulated Raman scattering. The effect of the field on deuterium-tritium deposition depends strongly on the source location, namely whether hot electrons are generated on field lines that connect to the capsule.

  8. Interplay of Laser-Plasma Interactions and Inertial Fusion Hydrodynamics

    Science.gov (United States)

    Strozzi, D. J.; Bailey, D. S.; Michel, P.; Divol, L.; Sepke, S. M.; Kerbel, G. D.; Thomas, C. A.; Ralph, J. E.; Moody, J. D.; Schneider, M. B.

    2017-01-01

    The effects of laser-plasma interactions (LPI) on the dynamics of inertial confinement fusion hohlraums are investigated via a new approach that self-consistently couples reduced LPI models into radiation-hydrodynamics numerical codes. The interplay between hydrodynamics and LPI—specifically stimulated Raman scatter and crossed-beam energy transfer (CBET)—mostly occurs via momentum and energy deposition into Langmuir and ion acoustic waves. This spatially redistributes energy coupling to the target, which affects the background plasma conditions and thus, modifies laser propagation. This model shows reduced CBET and significant laser energy depletion by Langmuir waves, which reduce the discrepancy between modeling and data from hohlraum experiments on wall x-ray emission and capsule implosion shape.

  9. Creation of a homogeneous plasma column by means of hohlraum radiation for ion-stopping measurements

    CERN Document Server

    Faik, Steffen; Basko, Mikhail M; Maruhn, Joachim A; Rosmej, Olga; Rienecker, Tim; Novikov, Vladimir G; Grushin, Alexander S

    2014-01-01

    In this work, we present the results of two-dimensional radiation-hydrodynamics simulations of a hohlraum target whose outgoing radiation is used to produce a homogeneously ionized carbon plasma for ion-beam stopping measurements. The cylindrical hohlraum with gold walls is heated by a frequency-doubled (\\lambda_l = 526.5 \\mu m) 1.4 ns long laser pulse with the total energy of E_l = 180 J. At the laser spot, the peak matter and radiation temperatures of, respectively, T ~ 380 eV and T_r ~ 120 eV are observed. X-rays from the hohlraum heat the attached carbon foam with a mean density of \\rho_C = 2 mg/cm^3 to a temperature of T ~ 25 eV. The simulation shows that the carbon ionization degree (Z ~ 3.75) and its column density stay relatively stable (within variations of about +-7%) long enough to conduct the ion-stopping measurements. Also, it is found that a special attention should be paid to the shock wave, emerging from the x-ray heated copper support plate, which at later times may significantly distort the ...

  10. Hybrid-PIC modeling of laser-plasma interactions and hot electron generation in gold hohlraum walls

    Science.gov (United States)

    Thoma, C.; Welch, D. R.; Clark, R. E.; Rose, D. V.; Golovkin, I. E.

    2017-06-01

    The walls of the hohlraum used in experiments at the national ignition facility are heated by laser beams with intensities ˜ 10 15 W/cm2, a wavelength of ˜ 1 / 3 μm, and pulse lengths on the order of a ns, with collisional absorption believed to be the primary heating mechanism. X-rays generated by the hot ablated plasma at the gold walls are then used to implode a target in the hohlraum interior. In addition to the collisional absorption of laser energy at the walls, non-linear laser-plasma interactions (LPI), such as stimulated Raman scattering and two plasmon decay, are believed to generate a population of supra-thermal electrons which, if present in the hohlraum, can have a deleterious effect on target implosion. We describe results of hohlraum modeling using a hybrid particle-in-cell code. To enable this work, new particle-based algorithms for a multiple-ion magneto-hydrodynamic (MHD) treatment, and a particle-based ray-tracing model were developed. The use of such hybrid methods relaxes the requirement to resolve the laser wavelength, and allows for relatively large-scale hohlraum simulations with a reasonable number of cells. But the non-linear effects which are believed to be the cause of hot electron generation can only be captured by fully kinetic simulations with good resolution of the laser wavelength. For this reason, we employ a two-tiered approach to hohlraum modeling. Large-scale simulations of the collisional absorption process can be conducted using the fast quasi-neutral MHD algorithm with fluid particle species. From these simulations, we can observe the time evolution of the hohlraum walls and characterize the density and temperature profiles. From these results, we can transition to smaller-scale highly resolved simulations using traditional kinetic particle-in-cell methods, from which we can fully model all of the non-linear laser-plasma interactions, as well as assess the details of the electron distribution function. We find that vacuum

  11. Stauts of the Laser Inertial Fusion Energy (LIFE) Hohlraum Point Design

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, P; Dunne, M; Ho, D; Lasinski, B; Meeker, D; Ross, J S

    2012-04-10

    Progress on the hohlraum point design for the LIFE engine is described. New features in the original design [Amendt et al., Fus. Sci. Technol. 60, 49 (2011)] are incorporated that address the imperatives of low target cost, high manufacturing throughput, efficient and prompt material recycling, an ability for near-term testing of key target design uncertainties on the National Ignition Facility, and robustness to target chamber environment and injection insults. To this end, the novel use of Pb hohlraums and aerogel-supported liquid DT fuel loading within a high-density-carbon (HDC) ablator is implemented in the hohlraum point design.

  12. Observation of hohlraum-wall motion with spectrally selective x-ray imaging at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, N., E-mail: izumi2@llnl.gov; Meezan, N. B.; Divol, L.; Hall, G. N.; Barrios, M. A.; Jones, O.; Landen, O. L.; Kroll, J. J.; Vonhof, S. A.; Nikroo, A.; Bailey, C. G.; Hardy, C. M.; Ehrlich, R. B.; Town, R. P. J.; Bradley, D. K.; Hinkel, D. E.; Moody, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Jaquez, J. [General Atomics, San Diego, California 9212 (United States)

    2016-11-15

    The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray drive symmetry throughout the laser pulse. When the outer cone beams strike the hohlraum wall, the plasma ablated off the hohlraum wall expands into the hohlraum and can alter both the outer and inner cone beam propagations and hence the X-ray drive symmetry especially at the final stage of the drive pulse. To quantitatively understand the wall motion, we developed a new experimental technique which visualizes the expansion and stagnation of the hohlraum wall plasma. Details of the experiment and the technique of spectrally selective x-ray imaging are discussed.

  13. Observation of hohlraum-wall motion with spectrally selective x-ray imaging at the National Ignition Facility

    Science.gov (United States)

    Izumi, N.; Meezan, N. B.; Divol, L.; Hall, G. N.; Barrios, M. A.; Jones, O.; Landen, O. L.; Kroll, J. J.; Vonhof, S. A.; Nikroo, A.; Jaquez, J.; Bailey, C. G.; Hardy, C. M.; Ehrlich, R. B.; Town, R. P. J.; Bradley, D. K.; Hinkel, D. E.; Moody, J. D.

    2016-11-01

    The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray drive symmetry throughout the laser pulse. When the outer cone beams strike the hohlraum wall, the plasma ablated off the hohlraum wall expands into the hohlraum and can alter both the outer and inner cone beam propagations and hence the X-ray drive symmetry especially at the final stage of the drive pulse. To quantitatively understand the wall motion, we developed a new experimental technique which visualizes the expansion and stagnation of the hohlraum wall plasma. Details of the experiment and the technique of spectrally selective x-ray imaging are discussed.

  14. Hot Electron Propagation and Imposed Magnetic Field in Inertial Fusion Hohlraums

    CERN Document Server

    Strozzi, D J; Marinak, M M; Larson, D J; Koning, J M; Logan, B G

    2015-01-01

    Simulations with the radiation-hydrodynamics code HYDRA of a low-adiabat ignition design for the National Ignition Facility (NIF), with and without an imposed axial magnetic field, are presented. We also study superthermal, or "hot," electron dynamics with the hybrid-PIC code ZUMA, using plasma conditions from HYDRA. During the early-time laser picket, when hot electrons from the window are a concern, we find ~2E-3 of the hot electron energy in a source consistent with two-plasmon decay (80 keV temperature) in the laser entrance hole deposits in the deuterium-tritium (DT) fuel, while most of the energy deposits in the high-Z wall. A 70 Tesla field, which may improve capsule performance, magnetizes hot electrons in the hohlraum fill gas, guides them to the capsule, and increases the DT deposition 12x. Early in peak laser power, electrons with >125 keV reach the DT fuel, and those with ~185 keV deposit the largest fraction of their energy (13%) in DT. HYDRA magnetohydrodynamics (MHD) simulations with an initial...

  15. A unified free-form representation applied to the shape optimization of the hohlraum with octahedral 6 laser entrance holes

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shaoen; Ding, Yongkun [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Huang, Yunbao, E-mail: Huangyblhy@gmail.com, E-mail: scmyking-2008@163.com; Li, Haiyan [Key Laboratory of Computer Integrated Manufacturing System, Guangdong University of Technology, Guangzhou 510006 (China); Jing, Longfei, E-mail: Huangyblhy@gmail.com, E-mail: scmyking-2008@163.com; Huang, Tianxuan [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China)

    2016-01-15

    The hohlraum is very crucial for indirect laser driven Inertial Confinement Fusion. Usually, its shape is designed as sphere, cylinder, or rugby with some kind of fixed functions, such as ellipse or parabola. Recently, a spherical hohlraum with octahedral 6 laser entrance holes (LEHs) has been presented with high flux symmetry [Lan et al., Phys. Plasmas 21, 010704 (2014); 21, 052704 (2014)]. However, there is only one shape parameter, i.e., the hohlraum to capsule radius ratio, being optimized. In this paper, we build the hohlraum with octahedral 6LEHs with a unified free-form representation, in which, by varying additional shape parameters: (1) available hohlraum shapes can be uniformly and accurately represented, (2) it can be used to understand why the spherical hohlraum has higher flux symmetry, (3) it allows us to obtain a feasible shape design field satisfying flux symmetry constraints, and (4) a synthetically optimized hohlraum can be obtained with a tradeoff of flux symmetry and other hohlraum performance. Finally, the hohlraum with octahedral 6LEHs is modeled, analyzed, and then optimized based on the unified free-form representation. The results show that a feasible shape design field with flux asymmetry no more than 1% can be obtained, and over the feasible design field, the spherical hohlraum is validated to have the highest flux symmetry, and a synthetically optimal hohlraum can be found with closing flux symmetry but larger volume between laser spots and centrally located capsule.

  16. Experimental characterization of hohlraum conditions by X-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Back, C.A.; Hsieh, E.J.; Kauffman, R.L. [and others

    1996-06-01

    Spectroscopy is a powerful technique used to measure the plasma parameters relevant to Inertial Confinement Fusion (ICF) plasmas. For instance, the onset of spectral signals from multilayer targets have been used to determine ablation rate scalings. Temperature and density measurements in coronal plasmas have enabled the study of laser coupling efficiency as a function of the laser wavelengths. More recently, dopants have been successfully used to determine capsule conditions of ICF targets. However, few spectroscopic studies have been performed to diagnose plasma conditions of the hohlraum itself. Several laboratories have studied enclosed cavities, previously concentrating on measurements of the radiative heat wave, the x-ray conversion efficiency, and temporal evolution of Au x rays. Measurements of electron temperature T{sub e} and electron densities n{sub e} are difficult because many physical processes occur and each diagnostic`s line-of-sight is restricted by the hohlraum wall. However, they are worth pursuing because they can provide critical information on the target energetics and the evolution of plasma parameters important to achieving fusion. Here the authors discuss spectroscopic tracers to diagnose plasma conditions in the hohlraum, using time- and space-resolved measurements. The tracers are typically mid-Z elements which are placed on the hohlraum wall or supended in the hohlraum volume. To demonstrate the breadth of measurements that can be performed, three types of experiments are presented.

  17. Wakes in Inertial Fusion Plasmas

    Science.gov (United States)

    Ellis, Ian Norman

    Plasma wave wakes, which are the collective oscillatory response near the plasma frequency to the propagation of particles or electromagnetic waves through a plasma, play a critical role in many plasma processes. New results from backwards stimulated Raman scattering (BSRS), in which wakes with phase velocities much less than the speed of light are induced by the beating of counter-propagating light waves, and from electron beam stopping, in which the wakes are produced by the motion of relativistically propagating electrons through the dense plasma, are discussed. Both processes play important roles in Inertial Confinement Fusion (ICF). In BSRS, laser light is scattered backwards out of the plasma, decreasing the energy available to compress the ICF capsule and affecting the symmetry of where the laser energy hits the hohlraum wall in indirect drive ICF. The plasma wave wake can also generate superthermal electrons that can preheat the core and/or the ablator. Electron beam stopping plays a critical role in the Fast Ignition (FI) ICF concept, in which a beam of relativistic electrons is used to heat the target core to ignition temperatures after the compression stage. The beam stopping power determines the effectiveness of the heating process. This dissertation covers new discoveries on the importance of plasma wave wakes in both BSRS and electron beam stopping. In the SRS studies, 1D particle-in-cell (PIC) simulations using OSIRIS are performed, which model a short-duration (˜500/ω0 --1FWHM) counter-propagating scattered light seed pulse in the presence of a constant pump laser with an intensity far below the absolute instability threshold for plasma waves undergoing Landau damping. The seed undergoes linear convective Raman amplification and dominates over the amplification of fluctuations due to particle discreteness. The simulation results are in good agreement with results from a coupled-mode solver when special relativity and the effects of finite size PIC

  18. Controlled fusion and plasma physics

    CERN Document Server

    Miyamoto, Kenro

    2006-01-01

    Resulting from ongoing, international research into fusion processes, the International Tokamak Experimental Reactor (ITER) is a major step in the quest for a new energy source.The first graduate-level text to cover the details of ITER, Controlled Fusion and Plasma Physics introduces various aspects and issues of recent fusion research activities through the shortest access path. The distinguished author breaks down the topic by first dealing with fusion and then concentrating on the more complex subject of plasma physics. The book begins with the basics of controlled fusion research, foll

  19. Investigating the hohlraum radiation properties through the angular distribution of the radiation temperature

    Science.gov (United States)

    Zhang, H.; Yang, D.; Song, P.; Zou, S.; Zhao, Y.; Li, S.; Li, Z.; Guo, L.; Wang, F.; Zheng, W.; Gu, P.; Pei, W.; Zhu, S.; Jiang, S.; Ding, Y.

    2016-08-01

    The symmetric radiation drive is essential to the capsule implosion in the indirect drive fusion but is hard to achieve due to the non-uniform radiation distribution inside the hohlraum. In this work, the non-uniform radiation properties of both vacuum and gas-filled hohlraums are studied by investigating the angular distribution of the radiation temperature experimentally and numerically. It is found that the non-uniform radiation distribution inside the hohlraum induces the variation of the radiation temperature between different view angles. The simulations show that both the angular distribution of the radiation temperature and the hohlraum radiation distribution can be affected by the electron heat flux. The measured angular distribution of the radiation temperature is more consistent with the simulations when the electron heat flux limiter f e = 0.1 . Comparisons between the experiments and simulations further indicate that the x-ray emission of the blow-off plasma is overestimated in the simulations when it stagnates around the hohlraum axis. The axial position of the laser spot can also be estimated by the angular distribution of the radiation temperature due to their sensitive dependence. The inferred laser spot moves closer to the laser entrance hole in the gas-filled hohlraum than that in the vacuum hohlraum, consisting with the x-ray images taken from the framing camera. The angular distribution of the radiation temperature provides an effective way to investigate the hohlraum radiation properties and introduces more constraint to the numerical modeling of the hohlraum experiments.

  20. Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

    Science.gov (United States)

    Ren, G.; Yan, J.; Liu, J.; Lan, K.; Chen, Y. H.; Huo, W. Y.; Fan, Z.; Zhang, X.; Zheng, J.; Chen, Z.; Jiang, W.; Chen, L.; Tang, Q.; Yuan, Z.; Wang, F.; Jiang, S.; Ding, Y.; Zhang, W.; He, X. T.

    2017-04-01

    We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 1 014- 1 015 W /cm2 intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Yn to be related to the laser energy EL, the hohlraum radius Rh, and the pulse duration τ through a scaling law of Yn∝(EL/Rh1.2τ0.2 )2.5. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

  1. EDITORIAL: Stochasticity in fusion plasmas Stochasticity in fusion plasmas

    Science.gov (United States)

    Unterberg, Bernhard

    2010-03-01

    Structure formation and transport in stochastic plasmas is a topic of growing importance in many fields of plasma physics from astrophysics to fusion research. In particular, the possibility to control transport in the boundary of confined fusion plasmas by resonant magnetic perturbations has been investigated extensively during recent years. A major research achievement was finding that the intense transient particle and heat fluxes associated with edge localized modes (here type-I ELMs) in magnetically confined fusion plasmas can be mitigated or even suppressed by resonant magnetic perturbation fields. This observation opened up a possible scheme to avoid too large erosion and material damage by such transients in future fusion devices such as ITER. However, it is widely recognized that a more basic understanding is needed to extrapolate the results obtained in present experiments to future fusion devices. The 4th workshop on Stochasticity in Fusion Plasmas was held in Jülich, Germany, from 2 to 4 March 2009. This series of workshops aims at gathering fusion experts from various plasma configurations such as tokamaks, stellarators and reversed field pinches to exchange knowledge on structure formation and transport in stochastic fusion plasmas. The workshops have attracted colleagues from both experiment and theory and stimulated fruitful discussions about the basics of stochastic fusion plasmas. Important papers from the first three workshops in 2003, 2005 and 2007 have been published in previous special issues of Nuclear Fusion (stacks.iop.org/NF/44/i=6, stacks.iop.org/NF/46/i=4 and stacks.iop.org/NF/48/i=2). This special issue comprises contributions presented at the 4th SFP workshop, dealing with the main subjects such as formation of stochastic magnetic layers, energy and particle transport in stochastic magnetic fields, plasma response to external, non-axis-symmetric perturbations and last but not least application of resonant magnetic perturbations for

  2. Controlled fusion and plasma physics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    This document presents the several speeches that took place during the 22nd European Physical Society conference on Controlled Fusion and Plasma Physics in Bournemouth, UK, between the 2nd and 7th July 1995. The talks deal with new experiments carried out on several tokamaks, particularly Tore Supra, concerning plasma confinement and fusion. Some information on specific fusion devices or tokamak devices is provided, as well as results of experiments concerning plasma instability. Separate abstracts were prepared for all the 31 papers in this volume. (TEC).

  3. Progress in octahedral spherical hohlraum study

    Directory of Open Access Journals (Sweden)

    Ke Lan

    2016-01-01

    Full Text Available In this paper, we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study. From our theoretical study, the octahedral spherical hohlraums with 6 Laser Entrance Holes (LEHs of octahedral symmetry have robust high symmetry during the capsule implosion at hohlraum-to-capsule radius ratio larger than 3.7. In addition, the octahedral spherical hohlraums also have potential superiority on low backscattering without supplementary technology. We studied the laser arrangement and constraints of the octahedral spherical hohlraums, and gave a design on the laser arrangement for ignition octahedral hohlraums. As a result, the injection angle of laser beams of 50°–60° was proposed as the optimum candidate range for the octahedral spherical hohlraums. We proposed a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields, in order to increase the laser coupling efficiency and improve the capsule symmetry and to mitigate the influence of the wall blowoff on laser transport. We studied on the sensitivity of the octahedral spherical hohlraums to random errors and compared the sensitivity among the octahedral spherical hohlraums, the rugby hohlraums and the cylindrical hohlraums, and the results show that the octahedral spherical hohlraums are robust to these random errors while the cylindrical hohlraums are the most sensitive. Up till to now, we have carried out three experiments on the spherical hohlraum with 2 LEHs on Shenguang(SG laser facilities, including demonstration of improving laser transport by using the cylindrical LEHs in the spherical hohlraums, spherical hohlraum energetics on the SGIII prototype laser facility, and comparisons of laser plasma instabilities between the spherical hohlraums and the cylindrical hohlraums on the SGIII laser facility.

  4. Plasma physics and fusion plasma electrodynamics

    CERN Document Server

    Bers, Abraham

    2016-01-01

    Plasma is a ubiquitous state of matter at high temperatures. The electrodynamics of plasmas encompasses a large number of applications, from understanding plasmas in space and the stars, to their use in processing semiconductors, and their role in controlled energy generation by nuclear fusion. This book covers collective and single particle dynamics of plasmas for fully ionized as well as partially ionized plasmas. Many aspects of plasma physics in current fusion energy generation research are addressed both in magnetic and inertial confinement plasmas. Linear and nonlinear dynamics in hydrodynamic and kinetic descriptions are offered, making both simple and complex aspects of the subject available in nearly every chapter. The approach of dividing the basic aspects of plasma physics as "linear, hydrodynamic descriptions" to be covered first because they are "easier", and postponing the "nonlinear and kinetic descriptions" for later because they are "difficult" is abandoned in this book. For teaching purpose...

  5. Fusion Plasma Theory project summaries

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    This Project Summary book is a published compilation consisting of short descriptions of each project supported by the Fusion Plasma Theory and Computing Group of the Advanced Physics and Technology Division of the Department of Energy, Office of Fusion Energy. The summaries contained in this volume were written by the individual contractors with minimal editing by the Office of Fusion Energy. Previous summaries were published in February of 1982 and December of 1987. The Plasma Theory program is responsible for the development of concepts and models that describe and predict the behavior of a magnetically confined plasma. Emphasis is given to the modelling and understanding of the processes controlling transport of energy and particles in a toroidal plasma and supporting the design of the International Thermonuclear Experimental Reactor (ITER). A tokamak transport initiative was begun in 1989 to improve understanding of how energy and particles are lost from the plasma by mechanisms that transport them across field lines. The Plasma Theory program has actively-participated in this initiative. Recently, increased attention has been given to issues of importance to the proposed Tokamak Physics Experiment (TPX). Particular attention has been paid to containment and thermalization of fast alpha particles produced in a burning fusion plasma as well as control of sawteeth, current drive, impurity control, and design of improved auxiliary heating. In addition, general models of plasma behavior are developed from physics features common to different confinement geometries. This work uses both analytical and numerical techniques. The Fusion Theory program supports research projects at US government laboratories, universities and industrial contractors. Its support of theoretical work at universities contributes to the office of Fusion Energy mission of training scientific manpower for the US Fusion Energy Program.

  6. Plasma physics for controlled fusion

    CERN Document Server

    Miyamoto, Kenro

    2016-01-01

    This new edition presents the essential theoretical and analytical methods needed to understand the recent fusion research of tokamak and alternate approaches. The author describes magnetohydrodynamic and kinetic theories of cold and hot plasmas in detail. The book covers new important topics for fusion studies such as plasma transport by drift turbulence, which depend on the magnetic configuration and zonal flows. These are universal phenomena of microturbulence. They can modify the onset criterion for turbulent transport, instabilities driven by energetic particles as well as alpha particle generation and typical plasma models for computer simulation. The fusion research of tokamaks with various new versions of H modes are explained. The design concept of ITER, the international tokamak experimental reactor, is described for inductively driven operations as well as steady-state operations using non-inductive drives. Alternative approaches of reversed-field pinch and its relaxation process, stellator includi...

  7. MAGNETOHYDRODYNAMIC MODELING FOR FUSION PLASMAS

    NARCIS (Netherlands)

    Keppens, R.; Goedbloed, J. P.; Blokland, J. W. S.

    2010-01-01

    The magnetohydrodynamic model for fusion plasma dynamics governs the large-scale equilibrium properties, and sets the most stringent constraints on the parameter space accessible without violent disruptions. In conjunction with linear stability analysis in the complex tokamak geometry, the MHD parad

  8. Ideal laser-beam propagation through high-temperature ignition Hohlraum plasmas.

    Science.gov (United States)

    Froula, D H; Divol, L; Meezan, N B; Dixit, S; Moody, J D; Neumayer, P; Pollock, B B; Ross, J S; Glenzer, S H

    2007-02-23

    We demonstrate that a blue (3omega, 351 nm) laser beam with an intensity of 2 x 10(15) W cm(-2) propagates nearly within the original beam cone through a millimeter scale, T(e)=3.5 keV high density (n(e)=5 x 10(20) cm(-3)) plasma. The beam produced less than 1% total backscatter at these high temperatures and densities; the resulting transmission is greater than 90%. Scaling of the electron temperature in the plasma shows that the plasma becomes transparent for uniform electron temperatures above 3 keV. These results are consistent with linear theory thresholds for both filamentation and backscatter instabilities inferred from detailed hydrodynamic simulations. This provides a strong justification for current inertial confinement fusion designs to remain below these thresholds.

  9. Turbulence measurements in fusion plasmas

    Science.gov (United States)

    Conway, G. D.

    2008-12-01

    Turbulence measurements in magnetically confined toroidal plasmas have a long history and relevance due to the detrimental role of turbulence induced transport on particle, energy, impurity and momentum confinement. The turbulence—the microscopic random fluctuations in particle density, temperature, potential and magnetic field—is generally driven by radial gradients in the plasma density and temperature. The correlation between the turbulence properties and global confinement, via enhanced diffusion, convection and direct conduction, is now well documented. Theory, together with recent measurements, also indicates that non-linear interactions within the turbulence generate large scale zonal flows and geodesic oscillations, which can feed back onto the turbulence and equilibrium profiles creating a complex interdependence. An overview of the current status and understanding of plasma turbulence measurements in the closed flux surface region of magnetic confinement fusion devices is presented, highlighting some recent developments and outstanding problems.

  10. Reproducibility of NIF hohlraum measurements

    Science.gov (United States)

    Moody, J. D.; Ralph, J. E.; Turnbull, D. P.; Casey, D. T.; Albert, F.; Bachmann, B. L.; Doeppner, T.; Divol, L.; Grim, G. P.; Hoover, M.; Landen, O. L.; MacGowan, B. J.; Michel, P. A.; Moore, A. S.; Pino, J. E.; Schneider, M. B.; Tipton, R. E.; Smalyuk, V. A.; Strozzi, D. J.; Widmann, K.; Hohenberger, M.

    2015-11-01

    The strategy of experimentally ``tuning'' the implosion in a NIF hohlraum ignition target towards increasing hot-spot pressure, areal density of compressed fuel, and neutron yield relies on a level of experimental reproducibility. We examine the reproducibility of experimental measurements for a collection of 15 identical NIF hohlraum experiments. The measurements include incident laser power, backscattered optical power, x-ray measurements, hot-electron fraction and energy, and target characteristics. We use exact statistics to set 1-sigma confidence levels on the variations in each of the measurements. Of particular interest is the backscatter and laser-induced hot-spot locations on the hohlraum wall. Hohlraum implosion designs typically include variability specifications [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. We describe our findings and compare with the specifications. This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

  11. Complex Spectra in Fusion Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hellermann, M.G. von; Jaspers, R. [FOM-Institute for Plasma Physics Rijnhuizen, Nieuwegein (Netherlands); Bertschinger, G.; Biel, W.; Marchuk, O. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik; Giroud, C.; Zastrow, K.D. [UKAEA Culham Laboratory Euratom Association, Abingdon (United Kingdom); Jupen, C. [Univ. of Lund (Sweden). Physics Dept.; O' Mullane, M.; Summers, H.P.; Whiteford, A. [Univ. of Strathclyde, Glasgow (United Kingdom). Applied Physics Dept.

    2005-12-15

    The need for quantitative evaluation of complex line emission spectra as observed in hot fusion plasmas initiated a challenging development of sophisticated interpretation tools based on integrating advanced atomic modelling with detailed treatment of the plasma environment. The successful merging of the two worlds has led to routine diagnostic procedures which have contributed enormously to the understanding of underlying plasma processes and also to a wide acceptance of spectroscopy as a reliable diagnostic method. In this paper three characteristic types of spectra of current and continuing interest are presented. The first is that of medium/heavy species with many ionisation stages revealed in survey VUV and XUV spectra. Such species occur as control gases, as wall materials, as ablated heavy species and possible as layered wall dopants for monitoring erosion. The spectra are complex with line-like and quasi-continuum regions and are amenable to advanced ?pattern recognition' methods. The second type is of few electron, highly ionised systems observed as line-of-sight integrated passive emission spectra in the soft X-ray region. They are analysed successfully in terms of plasma parameters through matching of observation with predicted synthetic spectra. Examples used here include highly resolved helium-like emission spectra of argon, iron and titanium observed on the tokamaks TEXTOR and Tore Supra. The third type, and the emphasis of this work, comprises spectra linked to active beam spectroscopy, that is, charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES). In this case, a complex spectrum is again composed of a (usually) dominating active spectrum and an underlying passive emission spectrum. Its analysis requires modelling of both active and passive features. Examples used here are from the CXRS diagnostic at JET and TEXTOR. They display characteristic features of the main light impurity ions (C{sup +6}, He{sup +2}, N

  12. A coordinate transformation method for calculating the 3D light intensity distribution in ICF hohlraum

    Science.gov (United States)

    Lin, Zhili; Li, Xiaoyan; Zhao, Kuixia; Chen, Xudong; Chen, Mingyu; Pu, Jixiong

    2016-06-01

    For an inertial confinement fusion (ICF) system, the light intensity distribution in the hohlraum is key to the initial plasma excitation and later laser-plasma interaction process. Based on the concept of coordinate transformation of spatial points and vector, we present a robust method with a detailed procedure that makes the calculation of the three dimensional (3D) light intensity distribution in hohlraum easily. The method is intuitive but powerful enough to solve the complex cases of random number of laser beams with arbitrary polarization states and incidence angles. Its application is exemplified in the Shenguang III Facility (SG-III) that verifies its effectiveness and it is useful for guiding the design of hohlraum structure parameter.

  13. Acceleration of compact toroid plasma rings for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, C.W.; Barr, W.L.; Eddleman, J.L.; Gee, M.; Hammer, J.H.; Ho, S.K.; Logan, B.G.; Meeker, D.J.; Mirin, A.A.; Nevins, W.M.

    1988-08-26

    We describe experimental results for a new type of collective accelerator based on magnetically confined compact torus (CT) plasma rings and discuss applications to both inertial and magnetic fusion. We have demonstrated the principle of CT acceleration in the RACE device with acceleration of 0.5 mg ring masses to 400 km/s and 0.02 mg ring masses to 1400 km/s at greater than or equal to30% efficiency. Scaling the CT accelerator to the multi-megajoule level could provide an efficient, economical driver for inertial fusion (ICF) or magnetically insulated inertial fusion. Efficient conversion to x-rays for driving hohlraum-type ICF targets has been modeled using a radiation-hydrodynamics code. At less demanding conditions than required for ICF, a CT accelerator can be applied to fueling and current drive in tokamaks. Fueling is accomplished by injecting CTs at the required rate to sustain the particle inventory and at a velocity sufficient to penetrate to the magnetic axis before CT dissolution. Current drive is a consequence of the magnetic helicity content of the CT, which is approximately conserved during reconnection of the CT fields with the tokamak. Major areas of uncertainty in CT fueling and current drive concern the mechanism by which CTs will stop in a tokamak plasma and the effects of the CT on energy confinement and magnetic stability. Bounds on the required CT injection velocity are obtained by considering drag due to emission of an Alfven-wave wake and rapid reconnection and tilting on the internal Alfven time scale of the CT. Preliminary results employing a 3-D, resistive MHD code show rapid tilting with the CT aligning its magnetic moment with the tokamak field. Requirements for an experimental test of CT injection and scenarios for fueling a reactor will also be discussed. 14 refs., 4 figs.

  14. Z-pinch driven hohlraums design for the 100 nanoseconds current time scale; Conception de cavites radiatives chauffees par plasma de striction magnetique en regime 100ns

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, F

    2003-12-15

    This work estimates Z-pinch driven hohlraums capabilities to obtain high temperatures (>200 eV). Simple models are proposed to calculate the performances offered by currents of 5 to 100 MA in 100 ns. The one dimensional physics of the Z-pinch at the length scale of its thickness and the hydrodynamics instabilities are studied. Then the enhancement of hohlraums performances with double nested Z-pinches or the use of an axial magnetic field is analysed. Z-pinch direct drive approach for inertial confinement fusion is finally considered. All the presented results are based on theoretical and 2D numerical approach and on the analysis of experimental results which were obtained on the american 'Z' generator. Annexes recall radiation MHD equations and check their validity for Z-pinch implosion. (author)

  15. Fusion. A voyage through the plasma universe

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelmsson, H. [Chalmers University of Technology, Goeteborg (Sweden)

    2000-07-01

    This book adopts a novel approach to fusion plasmas, covering fusion both in the laboratory and in the cosmos. It discusses the evolution of the field from early plasma research to the gigantic scientific efforts of today, covering basic fusion plasma science and laboratory fusion experiments as well as geocosmophysical and astrophysical projects. The description is interspersed with passages which suggest relationships between science and art or poetry. The author also relates meetings which he has had with famous scientists like Niels Bohr, Hannes Alfven, Piotr Kapitza, Subrahmanyan Chandrasekhar, Lyman Spitzer and others.

  16. Plasma Physics and Controlled Nuclear Fusion

    Science.gov (United States)

    Fisch, N. J.

    2010-01-01

    Already while making his famous contributions in uncontrolled nuclear fusion for wartime uses, Edward Teller contemplated how the abundant energy release through nuclear fusion might serve peacetime uses as well. His legacy in controlled nuclear fusion, and the associated physics of plasmas, spans both magnetic and inertial confinement approaches. His contributions in plasma physics, both the intellectual and the administrative, continue to impact the field.

  17. Plasma Physics An Introduction to Laboratory, Space, and Fusion Plasmas

    CERN Document Server

    Piel, Alexander

    2010-01-01

    Plasma Physics gives a comprehensive introduction to the basic processes in plasmas and demonstrates that the same fundamental concepts describe cold gas-discharge plasmas, space plasmas, and hot fusion plasmas. Starting from particle drifts in magnetic fields, the principles of magnetic confinement fusion are explained and compared with laser fusion. Collective processes are discussed in terms of plasma waves and instabilities. The concepts of plasma description by magnetohydrodynamics, kinetic theory, and particle simulation are stepwise introduced. Space charge effects in sheath regions, double layers and plasma diodes are given the necessary attention. The new fundamental mechanisms of dusty plasmas are explored and integrated into the framework of conventional plasmas. The book concludes with a brief introduction to plasma discharges. Written by an internationally renowned researcher in experimental plasma physics, the text keeps the mathematical apparatus simple and emphasizes the underlying concepts. T...

  18. Plasma physics and nuclear fusion research

    CERN Document Server

    Gill, Richard D

    1981-01-01

    Plasma Physics and Nuclear Fusion Research covers the theoretical and experimental aspects of plasma physics and nuclear fusion. The book starts by providing an overview and survey of plasma physics; the theory of the electrodynamics of deformable media and magnetohydrodynamics; and the particle orbit theory. The text also describes the plasma waves; the kinetic theory; the transport theory; and the MHD stability theory. Advanced theories such as microinstabilities, plasma turbulence, anomalous transport theory, and nonlinear laser plasma interaction theory are also considered. The book furthe

  19. Plasma physics an introduction to laboratory, space, and fusion plasmas

    CERN Document Server

    Piel, Alexander

    2017-01-01

    The enlarged new edition of this textbook provides a comprehensive introduction to the basic processes in plasmas and demonstrates that the same fundamental concepts describe cold gas-discharge plasmas, space plasmas, and hot fusion plasmas. Starting from particle drifts in magnetic fields, the principles of magnetic confinement fusion are explained and compared with laser fusion. Collective processes are discussed in terms of plasma waves and instabilities. The concepts of plasma description by magnetohydrodynamics, kinetic theory, and particle simulation are stepwise introduced. Space charge effects in sheath regions, double layers and plasma diodes are given the necessary attention. The novel fundamental mechanisms of dusty plasmas are explored and integrated into the framework of conventional plasmas. The book concludes with a concise description of modern plasma discharges. Written by an internationally renowned researcher in experimental plasma physics, the text keeps the mathematical apparatus simple a...

  20. Electron temperature measurements inside the ablating plasma of gas-filled hohlraums at the National Ignition Facility

    Science.gov (United States)

    Barrios, M. A.; Liedahl, D. A.; Schneider, M. B.; Jones, O.; Brown, G. V.; Regan, S. P.; Fournier, K. B.; Moore, A. S.; Ross, J. S.; Landen, O.; Kauffman, R. L.; Nikroo, A.; Kroll, J.; Jaquez, J.; Huang, H.; Hansen, S. B.; Callahan, D. A.; Hinkel, D. E.; Bradley, D.; Moody, J. D.

    2016-05-01

    The first measurement of the electron temperature (Te) inside a National Ignition Facility hohlraum is obtained using temporally resolved K-shell X-ray spectroscopy of a mid-Z tracer dot. Both isoelectronic- and interstage-line ratios are used to calculate the local Te via the collisional-radiative atomic physics code SCRAM [Hansen et al., High Energy Density Phys 3, 109 (2007)]. The trajectory of the mid-Z dot as it is ablated from the capsule surface and moves toward the laser entrance hole (LEH) is measured using side-on x-ray imaging, characterizing the plasma flow of the ablating capsule. Data show that the measured dot location is farther away from the LEH in comparison to the radiation-hydrodynamics simulation prediction using HYDRA [Marinak et al., Phys. Plasmas 3, 2070 (1996)]. To account for this discrepancy, the predicted simulation Te is evaluated at the measured dot trajectory. The peak Te, measured to be 4.2 keV ± 0.2 keV, is ˜0.5 keV hotter than the simulation prediction.

  1. Electron temperature measurements inside the ablating plasma of gas-filled hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Barrios, M. A.; Liedahl, D. A.; Schneider, M. B.; Jones, O.; Brown, G. V.; Fournier, K. B.; Moore, A. S.; Ross, J. S.; Landen, O.; Kauffman, R. L.; Nikroo, A.; Kroll, J.; Callahan, D. A.; Hinkel, D. E.; Bradley, D.; Moody, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Regan, S. P. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States); Jaquez, J.; Huang, H. [General Atomics, San Diego, California 92121 (United States); Hansen, S. B. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)

    2016-05-15

    The first measurement of the electron temperature (T{sub e}) inside a National Ignition Facility hohlraum is obtained using temporally resolved K-shell X-ray spectroscopy of a mid-Z tracer dot. Both isoelectronic- and interstage-line ratios are used to calculate the local T{sub e} via the collisional–radiative atomic physics code SCRAM [Hansen et al., High Energy Density Phys 3, 109 (2007)]. The trajectory of the mid-Z dot as it is ablated from the capsule surface and moves toward the laser entrance hole (LEH) is measured using side-on x-ray imaging, characterizing the plasma flow of the ablating capsule. Data show that the measured dot location is farther away from the LEH in comparison to the radiation-hydrodynamics simulation prediction using HYDRA [Marinak et al., Phys. Plasmas 3, 2070 (1996)]. To account for this discrepancy, the predicted simulation T{sub e} is evaluated at the measured dot trajectory. The peak T{sub e}, measured to be 4.2 keV ± 0.2 keV, is ∼0.5 keV hotter than the simulation prediction.

  2. Fundamentals of ICF Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, M D

    2005-09-30

    On the Nova Laser at LLNL, we demonstrated many of the key elements required for assuring that the next laser, the National Ignition Facility (NIF) will drive an Inertial Confinement Fusion (ICF) target to ignition. The indirect drive (sometimes referred to as ''radiation drive'') approach converts laser light to x-rays inside a gold cylinder, which then acts as an x-ray ''oven'' (called a hohlraum) to drive the fusion capsule in its center. On Nova we've demonstrated good understanding of the temperatures reached in hohlraums and of the ways to control the uniformity with which the x-rays drive the spherical fusion capsules. In these lectures we will be reviewing the physics of these laser heated hohlraums, recent attempts at optimizing their performance, and then return to the ICF problem in particular to discuss scaling of ICF gain with scale size, and to compare indirect vs. direct drive gains. In ICF, spherical capsules containing Deuterium and Tritium (DT)--the heavy isotopes of hydrogen--are imploded, creating conditions of high temperature and density similar to those in the cores of stars required for initiating the fusion reaction. When DT fuses an alpha particle (the nucleus of a helium atom) and a neutron are created releasing large amount amounts of energy. If the surrounding fuel is sufficiently dense, the alpha particles are stopped and can heat it, allowing a self-sustaining fusion burn to propagate radially outward and a high gain fusion micro-explosion ensues. To create those conditions the outer surface of the capsule is heated (either directly by a laser or indirectly by laser produced x-rays) to cause rapid ablation and outward expansion of the capsule material. A rocket-like reaction to that outward flowing heated material leads to an inward implosion of the remaining part of the capsule shell. The pressure generated on the outside of the capsule can reach nearly 100 megabar (100 million times

  3. Atomic and molecular processes in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Janev, R.K. [International Atomic Energy Agency, Vienna (Austria)

    1997-01-01

    The role of atomic and molecular processes in achieving and maintaining the conditions for thermonuclear burn in a magnetically confined fusion plasma is described. Emphasis is given to the energy balance and power and particle exhaust issues. The most important atomic and molecular processes which affect the radiation losses and impurity transport in the core plasma, the neutral particle transport in the plasma edge and the radiative cooling of divertor plasmas are discussed in greater detail. (author)

  4. Dynamics of a Z Pinch X Ray Source for Heating ICF Relevant Hohlraums to 120-160eV

    Energy Technology Data Exchange (ETDEWEB)

    SANFORD,THOMAS W. L.; OLSON,RICHARD E.; MOCK,RAYMOND CECIL; CHANDLER,GORDON A.; LEEPER,RAMON J.; NASH,THOMAS J.; RUGGLES,LAURENCE E.; SIMPSON,WALTER W.; STRUVE,KENNETH W.; PETERSON,D.L.; BOWERS,R.L.; MATUSKA,W.

    2000-07-10

    A z-pinch radiation source has been developed that generates 60 {+-} 20 KJ of x-rays with a peak power of 13 {+-} 4 TW through a 4-mm diameter axial aperture on the Z facility. The source has heated NIF (National Ignition Facility)-scale (6-mm diameter by 7-mm high) hohlraums to 122 {+-} 6 eV and reduced-scale (4-mm diameter by 4-mm high) hohlraums to 155 {+-} 8 eV -- providing environments suitable for indirect-drive ICF (Inertial Confinement Fusion) studies. Eulerian-RMHC (radiation-hydrodynamics code) simulations that take into account the development of the Rayleigh-Taylor instability in the r-z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm{sup 3} CH{sub 2} fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by {approximately}40% with only a 3--5% decrease in peak temperature, in agreement with measurements.

  5. Plasma Physics and Controlled Nuclear Fusion

    CERN Document Server

    Miyamoto, Kenro

    2005-01-01

    The primary objectives of this book are, firstly, to present the essential theoretical background needed to understand recent fusion research and, secondly, to describe the current status of fusion research for graduate students and senior undergraduates. It will also serve as a useful reference for scientists and engineers working in the related fields. In Part I, Plasma Physics, the author explains the basics of magneto-hydrodynamics and kinetic theory in a simple and compact way and, at the same time, covers important new topics for fusion studies such as the ballooning representation, instabilities driven by energetic particles and various plasma models for computer simulations. Part II, Controlled Nuclear Fusion, attempts to review the "big picture" in fusion research. All important phenomena and technologies are addressed, with a particular emphasis on the topics of most concern in current research.

  6. Radiation drive in laser heated hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Suter, L.J.; Kauffman, R.L.; Darrow, C.B. [and others

    1995-11-03

    Nearly 10 years of Nova experiments and analysis have lead to a relatively detailed quantitative and qualitative understanding of radiation drive in laser heated hohlraums. Our most successful quantitative modelling tool is 2D Lasnex numerical simulations. Analysis of the simulations provides us with insight into the details of the hohlraum drive. In particular we find hohlraum radiation conversion efficiency becomes quite high with longer pulses as the accumulated, high Z blow-off plasma begins to radiate. Extensive Nova experiments corroborate our quantitative and qualitative understanding.

  7. Radiation reaction in fusion plasmas.

    Science.gov (United States)

    Hazeltine, R D; Mahajan, S M

    2004-10-01

    The effects of a radiation reaction on thermal electrons in a magnetically confined plasma, with parameters typical of planned burning plasma experiments, are studied. A fully relativistic kinetic equation that includes the radiation reaction is derived. The associated rate of phase-space contraction is computed and the relative importance of the radiation reaction in phase space is estimated. A consideration of the moments of the radiation reaction force show that its effects are typically small in reactor-grade confined plasmas, but not necessarily insignificant.

  8. Causality detection and turbulence in fusion plasmas

    CERN Document Server

    van Milligen, B Ph; Ramisch, M; Estrada, T; Hidalgo, C; Alonso, A

    2013-01-01

    This work explores the potential of an information-theoretical causality detection method for unraveling the relation between fluctuating variables in complex nonlinear systems. The method is tested on some simple though nonlinear models, and guidelines for the choice of analysis parameters are established. Then, measurements from magnetically confined fusion plasmas are analyzed. The selected data bear relevance to the all-important spontaneous confinement transitions often observed in fusion plasmas, fundamental for the design of an economically attractive fusion reactor. It is shown how the present method is capable of clarifying the interaction between fluctuating quantities such as the turbulence amplitude, turbulent flux, and Zonal Flow amplitude, and uncovers several interactions that were missed by traditional methods.

  9. EDITORIAL: Plasma Surface Interactions for Fusion

    Science.gov (United States)

    2006-05-01

    Because plasma-boundary physics encompasses some of the most important unresolved issues for both the International Thermonuclear Experimental Reactor (ITER) project and future fusion power reactors, there is a strong interest in the fusion community for better understanding and characterization of plasma wall interactions. Chemical and physical sputtering cause the erosion of the limiters/divertor plates and vacuum vessel walls (made of C, Be and W, for example) and degrade fusion performance by diluting the fusion fuel and excessively cooling the core, while carbon redeposition could produce long-term in-vessel tritium retention, degrading the superior thermo-mechanical properties of the carbon materials. Mixed plasma-facing materials are proposed, requiring optimization for different power and particle flux characteristics. Knowledge of material properties as well as characteristics of the plasma material interaction are prerequisites for such optimizations. Computational power will soon reach hundreds of teraflops, so that theoretical and plasma science expertise can be matched with new experimental capabilities in order to mount a strong response to these challenges. To begin to address such questions, a Workshop on New Directions for Advanced Computer Simulations and Experiments in Fusion-Related Plasma Surface Interactions for Fusion (PSIF) was held at the Oak Ridge National Laboratory from 21 to 23 March, 2005. The purpose of the workshop was to bring together researchers in fusion related plasma wall interactions in order to address these topics and to identify the most needed and promising directions for study, to exchange opinions on the present depth of knowledge of surface properties for the main fusion-related materials, e.g., C, Be and W, especially for sputtering, reflection, and deuterium (tritium) retention properties. The goal was to suggest the most important next steps needed for such basic computational and experimental work to be facilitated

  10. Plasma surface interactions in controlled fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Ghendrih, Ph.; Becoulet, M.; Costanzo, L. [and others

    2000-07-01

    This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak.

  11. Perturbative Transport Studies in Fusion Plasmas

    NARCIS (Netherlands)

    Cardozo, N. J. L.

    1995-01-01

    Studies of transport in fusion plasmas using perturbations of an equilibrium state reviewed. Essential differences between steady-state and perturbative transport studies are pointed out. Important transport issues that can be addressed with perturbative experiments are identified as: (i) Are the tr

  12. Novel spherical hohlraum with cylindrical laser entrance holes and shields

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Ke [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Zheng, Wudi [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2014-09-15

    Our recent works [K. Lan et al., Phys. Plasmas 21, 010704 (2014); K. Lan et al., Phys. Plasmas 21, 052704 (2014)] have shown that the octahedral spherical hohlraums are superior to the cylindrical hohlraums in both higher symmetry during the capsule implosion and lower backscatter without supplementary technology. However, both the coupling efficiency from the drive laser energy to the capsule and the capsule symmetry decrease remarkably when larger laser entrance holes (LEHs) are used. In addition, the laser beams injected at angles > 45° transport close to the hohlraum wall, thus the wall blowoff causes the LEH to close faster and results in strong laser plasma interactions inside the spherical hohlraums. In this letter, we propose a novel octahedral hohlraum with LEH shields and cylindrical LEHs to alleviate these problems. From our theoretical study, with the LEH shields, the laser coupling efficiency is significantly increased and the capsule symmetry is remarkably improved in the spherical hohlraums. The cylindrical LEHs take advantage of the cylindrical hohlraum near the LEH and mitigate the influence of the blowoff on laser transport inside a spherical hohlraum. The cylindrical LEHs can also be applied to the rugby and elliptical hohlraums.

  13. Dust remobilization in fusion plasmas

    CERN Document Server

    Tolias, P; De Angeli, M; De Temmerman, G; Ripamonti, D; Riva, G; Bykov, I; Shalpegin, A; Vignitchouk, L; Brochard, F; Bystrov, K; Bardin, S; Litnovsky, A

    2016-01-01

    The first combined experimental and theoretical studies of dust remobilization by plasma forces are reported. The main theoretical aspects of remobilization are analyzed. In particular, the dominant role of adhesive forces is highlighted and generic remobilization conditions - detachment, sliding, rolling - are formulated. A novel experimental technique is proposed, based on controlled adhesion of dust grains on tungsten samples combined with detailed mapping of the dust deposition profile prior and post plasma exposure. Proof-of-principle experiments in the TEXTOR tokamak and the EXTRAP-T2R reversed-field pinch are presented. The versatile environment of the linear device Pilot-PSI allowed for experiments with different magnetic field topologies and varying plasma conditions that were complemented with camera observations.

  14. Doppler tomography in fusion plasmas and astrophysics

    CERN Document Server

    Salewski, Mirko; Heidbrink, Bill; Jacobsen, Asger Schou; Korsholm, Soren Bang; Leipold, Frank; Madsen, Jens; Moseev, Dmitry; Nielsen, Stefan Kragh; Rasmussen, Jesper; Stagner, Luke; Steeghs, Danny; Stejner, Morten; Tardini, Giovani; Weiland, Markus

    2015-01-01

    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion D-alpha (FIDA) spectroscopy measurements in magnetically confined plasma, the D-alpha-photons are likewise Doppler-shifted ultimately due to gyration of the fast ions. In either case, spectra of Doppler-shifted line emission are sensitive to the velocity distribution of the emitters. Astrophysical Doppler tomography has lead to images of accretion discs of binaries revealing bright spots, spiral structures, and flow patterns. Fusion plasma Doppler tomography has lead to an image of the fast-ion velocity distribution function in the tokamak ASDEX Upgrade. This image matched numerical simulations very well. Here we discuss achievements of the Doppler tomography approach, its promise and limits, analogies and differences in astrophysical and fusion plasma Doppler tomography, and what ...

  15. Optimizing implosion yields using rugby-shaped hohlraums

    Science.gov (United States)

    Park, Hye-Sook; Robey, H.; Amendt, P.; Philippe, F.; Casner, A.; Caillaud, T.; Bourgade, J.-L.; Landoas, O.; Li, C. K.; Petrasso, R.; Seguin, F.; Rosenberg, M.; Glebov, V. Yu.

    2009-11-01

    We present the first experimental results on optimizing capsule implosion experiments by using rugby-shaped hohlraums [1] on the Omega laser, University of Rochester. This campaign compared D2-filled capsule performance between standard cylindrical Au hohlraums and rugby-shaped hohlraums for demonstrating the energetics advantages of the rugby geometry. Not only did the rugby-shaped hohlraums show nearly 20% more x-ray drive energy over the cylindrical hohlraums, but also the high-performance design of the capsules provided nearly 20 times more DD neutrons than in any previous Omega hohlraum campaigns, thereby enabling use of neutron temporal diagnostics. Comparison with simulations on neutron burn histories, x-ray core imaging, backscattered laser light and radiation temperature are presented. [1] P. Amendt et al., Phys. Plasmas 15, 012702 (2008)

  16. Plasma physics for controlled fusion. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Kenro

    2016-08-01

    This new edition presents the essential theoretical and analytical methods needed to understand the recent fusion research of tokamak and alternate approaches. The author describes magnetohydrodynamic and kinetic theories of cold and hot plasmas in detail. The book covers new important topics for fusion studies such as plasma transport by drift turbulence, which depend on the magnetic configuration and zonal flows. These are universal phenomena of microturbulence. They can modify the onset criterion for turbulent transport, instabilities driven by energetic particles as well as alpha particle generation and typical plasma models for computer simulation. The fusion research of tokamaks with various new versions of H modes are explained. The design concept of ITER, the international tokamak experimental reactor, is described for inductively driven operations as well as steady-state operations using non-inductive drives. Alternative approaches of reversed-field pinch and its relaxation process, stellator including quasi-symmetric system, open-end system of tandem mirror and inertial confinement are also explained. Newly added and updated topics in this second edition include zonal flows, various versions of H modes, and steady-state operations of tokamak, the design concept of ITER, the relaxation process of RFP, quasi-symmetric stellator, and tandem mirror. The book addresses graduate students and researchers in the field of controlled fusion.

  17. Hydro-Coupling Effects on Compression Symmetry in Gas-Filled Hohlraum Experiments at the Omega Laser

    Energy Technology Data Exchange (ETDEWEB)

    Dewalds, E L; Pollaine, S W; Landen, O L; Amendt, P A; Turner, R E; Wallace, R; Campbell, K M; Glenzer, S H

    2003-08-26

    Ignition hohlraum designs use low Z gas fill to slow down the inward progress of high Z ablated plasma from the hohlraum walls preventing large laser spot motion and capsule drive asymmetries. In order to optimize the ignition design, the gas hydro-coupling effect to a fusion capsule asymmetry is presently being assessed in experiments at the Omega laser facility with gas filled hohlraums and foam balls. Our experiments measure the effects of the pressure spike that is generated by direct gas heating by the drive laser beams on the capsule surrogate for various hohlraum gas fill densities (0-2.5 mg/cc). To isolate the effect of the gas-hydro coupling pressure, we have begun by using plastic ''hohlraums'' to reduce the x-ray ablation pressure. The foam ball images measured by x-ray backlighting show increasing pole-hot pressure asymmetry for increasing gas pressure. In addition, the gas hydrodynamics is studied by imaging of a low concentration Xe gas fill dopant. The gas fill self-emission. shows the early pressure spike and its propagation towards the foam ball, as well as the gas stagnation on the holraum axis at later times, both contributing to the capsule asymmetry. These first gas hydro-coupling results are compared to LASNEX simulations.

  18. Magnetized Target Fusion Driven by Plasma Liners

    Science.gov (United States)

    Thio, Y. C. Francis; Cassibry, Jason; Eskridge, Richard; Kirkpatrick, Ronald C.; Knapp, Charles E.; Lee, Michael; Martin, Adam; Smith, James; Wu, S. T.; Rodgers, Stephen L. (Technical Monitor)

    2001-01-01

    For practical applications of magnetized target fusion, standoff drivers to deliver the imploding momentum flux to the target plasma remotely are required. Quasi-spherically converging plasma jets have been proposed as standoff drivers for this purpose. The concept involves the dynamic formation of a quasi-spherical plasma liner by the merging of plasma jets, and the use of the liner so formed to compress a spheromak or a field reversed configuration (FRC). Theoretical analysis and computer modeling of the concept are presented. It is shown that, with the appropriate choice of the flow parameters in the liner and the target, the impact between the liner and the target plasma can be made to be shockless in the liner or to generate at most a very weak shock in the liner. Additional information is contained in the original extended abstract.

  19. BOOK REVIEW: Controlled Fusion and Plasma Physics

    Science.gov (United States)

    Engelmann, F.

    2007-07-01

    This new book by Kenro Miyamoto provides an up-to-date overview of the status of fusion research and the important parts of the underlying plasma physics at a moment where, due to the start of ITER construction, an important step in fusion research has been made and many new research workers will enter the field. For them, and also for interested graduate students and physicists in other fields, the book provides a good introduction into fusion physics as, on the whole, the presentation of the material is quite appropriate for getting acquainted with the field on the basis of just general knowledge in physics. There is overlap with Miyamoto's earlier book Plasma Physics for Nuclear Fusion (MIT Press, Cambridge, USA, 1989) but only in a few sections on subjects which have not evolved since. The presentation is subdivided into two parts of about equal length. The first part, following a concise survey of the physics basis of thermonuclear fusion and of plasmas in general, covers the various magnetic configurations studied for plasma confinement (tokamak; reversed field pinch; stellarator; mirror-type geometries) and introduces the specific properties of plasmas in these devices. Plasma confinement in tokamaks is treated in particular detail, in compliance with the importance of this field in fusion research. This includes a review of the ITER concept and of the rationale for the choice of ITER's parameters. In the second part, selected topics in fusion plasma physics (macroscopic instabilities; propagation of waves; kinetic effects such as energy transfer between waves and particles including microscopic instabilities as well as plasma heating and current drive; transport phenomena induced by turbulence) are presented systematically. While the emphasis is on displaying the essential physics, deeper theoretical analysis is also provided here. Every chapter is complemented by a few related problems, but only partial hints for their solution are given. A selection of

  20. Far infrared fusion plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Luhmann, N.C. Jr.; Peebles, W.A.

    1990-01-01

    Over the last several years, reflectometry has grown in importance as a diagnostic for both steady-state density Profiles as well as for the investigation of density fluctuations and turbulence. As a diagnostic for density profile measurement, it is generally believed to be well understood in the tokamak environment. However, its use as a fluctuation diagnostic is hampered by a lack of quantitative experimental understanding of its wavenumber sensitivity and spatial resolution. Several researchers, have theoretically investigated these questions. However, prior to the UCLA laboratory investigation, no group has experimentally investigated these questions. Because of the reflectometer's importance to the world effort in understanding plasma turbulence and transport, UCLA has, over the last year, made its primary Task IIIA effort the resolution of these questions. UCLA has taken the lead in a quantitative experimental understanding of reflectometer data as applied to the measurement of density fluctuations. In addition to this, work has proceeded on the design, construction, and installation of a reflectometer system on UCLA's CCT tokamak. This effort will allow a comparison between the improved confinement regimes (H-mode) observed on both the DIII-D and CCT machines with the goal of achieving a physics understanding of the phenomena. Preliminary investigation of a new diagnostic technique to measure density profiles as a function of time has been initiated at UCLA. The technique promises to be a valuable addition to the range of available plasma diagnostics. Work on advanced holographic reflectometry technique as applied to fluctuation diagnostics has awaited a better understanding of the reflectometer signal itself as discussed above. Efforts to ensure the transfer of the diagnostic developments have continued with particular attention devoted to the preliminary design of a multichannel FIR interferometer for MST.

  1. Inertial confinement fusion quarterly report, July--September 1994. Volume 4, Number 4

    Energy Technology Data Exchange (ETDEWEB)

    Honea, E. [ed.

    1994-09-01

    The ICF Quarterly continues with six articles in this issue describing recent developments in the Inertial Confinement Fusion (ICF) Program at Lawrence Livermore National Laboratory. The topics include plasma characterization, production of millimeter scale-length plasmas for studying laser-plasma instabilities, hohlraum physics, three-dimensional hydrodynamic modeling, crystal growth, and laser-beam smoothing.

  2. Introduction to plasma physics and controlled fusion

    CERN Document Server

    Chen, Francis F

    1984-01-01

    This complete introduction to plasma physics and controlled fusion by one of the pioneering scientists in this expanding field offers both a simple and intuitive discussion of the basic concepts of this subject and an insight into the challenging problems of current research. In a wholly lucid manner the work covers single-particle motions, fluid equations for plasmas, wave motions, diffusion and resistivity, Landau damping, plasma instabilities and nonlinear problems. For students, this outstanding text offers a painless introduction to this important field; for teachers, a large collection of problems; and for researchers, a concise review of the fundamentals as well as original treatments of a number of topics never before explained so clearly. This revised edition contains new material on kinetic effects, including Bernstein waves and the plasma dispersion function, and on nonlinear wave equations and solitons.

  3. Fundamentals of plasma physics and controlled fusion

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Kenro

    2000-10-01

    The present lecture note was written to fill a gap between text books for undergraduates and specific review articles written by specialists for their young colleagues. The note may be divided in three parts. The first part is on basic characteristics of a plasma in a magnetic field. The second part describes plasma confinement and heating with an emphasis on magnetohydrodynamic instabilities. In addition, propagation of plasma waves, plasma heating by electromagnetic waves are given. The third part is devoted to various specific concepts of nuclear fusion. Emphases are placed on toroidal devices, especially on tokamak devices and stellarators. One might feel heavy mathematics glimpsing the present note, especially in the part treating magnetohydrodynamic instabilities. (author)

  4. Quantifying self-organization in fusion plasmas

    Science.gov (United States)

    Rajković, M.; Milovanović, M.; Škorić, M. M.

    2017-05-01

    A multifaceted framework for understanding self-organization in fusion plasma dynamics is presented which concurrently manages several important issues related to the nonlinear and multiscale phenomena involved, namely,(1) it chooses the optimal template wavelet for the analysis of temporal or spatio-temporal plasma dynamics, (2) it detects parameter values at which bifurcations occur, (3) it quantifies complexity and self-organization, (4) it enables short-term prediction of nonlinear dynamics, and (5) it extracts coherent structures in turbulence by separating them from the incoherent component. The first two aspects including the detection of changes in the dynamics of a nonlinear system are illustrated by analyzing Stimulated Raman Scattering in a bounded, weakly dissipative plasma. Self-organization in the fusion plasma is quantitatively analyzed based on the numerical simulations of the Gyrokinetic-Vlasov (GKV) model of plasma dynamics. The parameters for the standard and inward shifted magnetic configurations, relevant for the Large Helical Device, were used in order to quantitatively compare self-organization and complexity in the two configurations. Finally, self-organization is analyzed for three different confinement regimes of the MAST device.

  5. Massachusetts Institute of Technology, Plasma Fusion Center, Technical Research Programs

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Ronald C.

    1980-08-01

    A review is given of the technical programs carried out by the Plasma Fusion Center. The major divisions of work areas are applied plasma research, confinement experiments, fusion technology and engineering, and fusion systems. Some objectives and results of each program are described. (MOW)

  6. The physics of radiation driven ICF hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, M.D.

    1995-08-07

    On the Nova Laser at LLNL, we have recently demonstrated many of the key elements required for assuring that the next proposed laser, the National Ignition Facility (NIF) will drive an Inertial Confinement Fusion (ICF) target to ignition. The target uses the recently declassified indirect drive (sometimes referred to as {open_quotes}radiation drive{close_quotes}) approach which converts laser light to x-rays inside a gold cylinder, which then acts as an x-ray {open_quotes}oven{close_quotes} (called a hohlraum) to drive the fusion capsule in its center. On Nova we`ve demonstrated good understanding of the temperatures reached in hohlraums and of the ways to control the uniformity with which the x-rays drive the spherical fusion capsules. In this lecture we briefly review the fundamentals of ICF, and describe the capsule implosion symmetry advantages of the hohlraum approach. We then concentrate on a quantitative understanding of the scaling of radiation drive with hohlraum size and wall material, and with laser pulse length and power. We demonstrate that coupling efficiency of x-ray drive to the capsule increases as we proceed from Nova to the NIF and eventually to a reactor, thus increasing the gain of the system.

  7. Progress in hohlraum physics for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Moody, J. D., E-mail: moody4@llnl.gov; Callahan, D. A.; Hinkel, D. E.; Amendt, P. A.; Baker, K. L.; Bradley, D.; Celliers, P. M.; Dewald, E. L.; Divol, L.; Döppner, T.; Eder, D. C.; Edwards, M. J.; Jones, O.; Haan, S. W.; Ho, D.; Hopkins, L. B.; Izumi, N.; Kalantar, D.; Kauffman, R. L.; Kilkenny, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); and others

    2014-05-15

    Advances in hohlraums for inertial confinement fusion at the National Ignition Facility (NIF) were made this past year in hohlraum efficiency, dynamic shape control, and hot electron and x-ray preheat control. Recent experiments are exploring hohlraum behavior over a large landscape of parameters by changing the hohlraum shape, gas-fill, and laser pulse. Radiation hydrodynamic modeling, which uses measured backscatter, shows that gas-filled hohlraums utilize between 60% and 75% of the laser power to match the measured bang-time, whereas near-vacuum hohlraums utilize 98%. Experiments seem to be pointing to deficiencies in the hohlraum (instead of capsule) modeling to explain most of the inefficiency in gas-filled targets. Experiments have begun quantifying the Cross Beam Energy Transfer (CBET) rate at several points in time for hohlraum experiments that utilize CBET for implosion symmetry. These measurements will allow better control of the dynamic implosion symmetry for these targets. New techniques are being developed to measure the hot electron energy and energy spectra generated at both early and late time. Rugby hohlraums offer a target which requires little to no CBET and may be less vulnerable to undesirable dynamic symmetry “swings.” A method for detecting the effect of the energetic electrons on the fuel offers a direct measure of the hot electron effects as well as a means to test energetic electron mitigation methods. At higher hohlraum radiation temperatures (including near vacuum hohlraums), the increased hard x-rays (1.8–4 keV) may pose an x-ray preheat problem. Future experiments will explore controlling these x-rays with advanced wall materials.

  8. Thomson scattering from laser plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Moody, J D; Alley, W E; De Groot, J S; Estabrook, K G; Glenzer, S H; Hammer, J H; Jadaud, J P; MacGowan, B J; Rozmus, W; Suter, L J; Williams, E A

    1999-01-12

    Thomson scattering has recently been introduced as a fundamental diagnostic of plasma conditions and basic physical processes in dense, inertial confinement fusion plasmas. Experiments at the Nova laser facility [E. M. Campbell et al., Laser Part. Beams 9, 209 (1991)] have demonstrated accurate temporally and spatially resolved characterization of densities, electron temperatures, and average ionization levels by simultaneously observing Thomson scattered light from ion acoustic and electron plasma (Langmuir) fluctuations. In addition, observations of fast and slow ion acous- tic waves in two-ion species plasmas have also allowed an independent measurement of the ion temperature. These results have motivated the application of Thomson scattering in closed-geometry inertial confinement fusion hohlraums to benchmark integrated radiation-hydrodynamic modeling of fusion plasmas. For this purpose a high energy 4{omega} probe laser was implemented recently allowing ultraviolet Thomson scattering at various locations in high-density gas-filled hohlraum plasmas. In partic- ular, the observation of steep electron temperature gradients indicates that electron thermal transport is inhibited in these gas-filled hohlraums. Hydrodynamic calcula- tions which include an exact treatment of large-scale magnetic fields are in agreement with these findings. Moreover, the Thomson scattering data clearly indicate axial stagnation in these hohlraums by showing a fast rise of the ion temperature. Its timing is in good agreement with calculations indicating that the stagnating plasma will not deteriorate the implosion of the fusion capsules in ignition experiments.

  9. Introduction to plasma physics and controlled fusion

    CERN Document Server

    Chen, Francis F

    2016-01-01

    The third edition of this classic text presents a complete introduction to plasma physics and controlled fusion, written by one of the pioneering scientists in this expanding field.  It offers both a simple and intuitive discussion of the basic concepts of the subject matter and an insight into the challenging problems of current research. This outstanding text offers students a painless introduction to this important field; for teachers, a large collection of problems; and for researchers, a concise review of the fundamentals as well as original treatments of a number of topics never before explained so clearly.  In a wholly lucid manner the second edition covered charged-particle motions, plasmas as fluids, kinetic theory, and nonlinear effects.  For the third edition, two new chapters have been added to incorporate discussion of more recent advances in the field.  The new chapter 9 on Special Plasmas covers non-neutral plasmas, pure electron plasmas, solid and ultra-cold plasmas, pair-ion plasmas, d...

  10. Improving Hohlraums for High Foot Implosions

    Science.gov (United States)

    Hinkel, D. E.; Berzak Hopkins, L. F.; Ma, T.; Ralph, J. E.; Albert, F.; Benedetti, L. R.; Celliers, P. M.; Doeppner, T.; Goyon, C. S.; Izumi, N.; Jarrott, L. C.; Khan, S. F.; Kline, J. L.; Kritcher, A. L.; Kyrala, G. A.; Nagel, S. R.; Pak, A. E.; Patel, P.; Rosen, M. D.; Rygg, J. R.; Schneider, M. B.; Turnbull, D. P.; Yeamans, C. B.; Callahan, D. A.; Hurricane, O. A.

    2016-10-01

    Analysis of High Foot implosions show that performance has been limited by the radiation drive environment, i.e., the hohlraum. Demonstrated here is that improvements in the radiation environment result in an enhancement in implosion performance. This is accomplished by using a longer, larger case-to-capsule ratio hohlraum at lower gas fill density. At fixed laser energy, High Foot implosions driven with this hohlraum have achieved a 1.4 x increase in stagnation pressure, with an accompanying relative increase in fusion yield of 50%. Low mode asymmetries are still present, however, and are most likely a consequence of poor inner beam propagation through the hohlraum to the wall. Presented here are results from these High Foot implosions, as well as analyses of inner beam propagation, and additional hohlraum improvements that further ameliorate the implosion. This work performed under the auspices of U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  11. Synthetic diagnostics platform for fusion plasmas (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Shi, L., E-mail: lshi@pppl.gov; Valeo, E. J.; Tobias, B. J.; Kramer, G. J.; Hausammann, L.; Tang, W. M. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Chen, M. [Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616 (United States)

    2016-11-15

    A Synthetic Diagnostics Platform (SDP) for fusion plasmas has been developed which provides state of the art synthetic reflectometry, beam emission spectroscopy, and Electron Cyclotron Emission (ECE) diagnostics. Interfaces to the plasma simulation codes GTC, XGC-1, GTS, and M3D-C{sup 1} are provided, enabling detailed validation of these codes. In this paper, we give an overview of SDP’s capabilities, and introduce the synthetic diagnostic modules. A recently developed synthetic ECE Imaging module which self-consistently includes refraction, diffraction, emission, and absorption effects is discussed in detail. Its capabilities are demonstrated on two model plasmas. The importance of synthetic diagnostics in validation is shown by applying the SDP to M3D-C{sup 1} output and comparing it with measurements from an edge harmonic oscillation mode on DIII-D.

  12. Generation and Beaming of Early Hot Electrons onto the Capsule in Laser-Driven Ignition Hohlraums

    Science.gov (United States)

    Dewald, E. L.; Hartemann, F.; Michel, P.; Milovich, J.; Hohenberger, M.; Pak, A.; Landen, O. L.; Divol, L.; Robey, H. F.; Hurricane, O. A.; Döppner, T.; Albert, F.; Bachmann, B.; Meezan, N. B.; MacKinnon, A. J.; Callahan, D.; Edwards, M. J.

    2016-02-01

    In hohlraums for inertial confinement fusion (ICF) implosions on the National Ignition Facility, suprathermal hot electrons, generated by laser plasma instabilities early in the laser pulse ("picket") while blowing down the laser entrance hole (LEH) windows, can preheat the capsule fuel. Hard x-ray imaging of a Bi capsule surrogate and of the hohlraum emissions, in conjunction with the measurement of time-resolved bremsstrahlung spectra, allows us to uncover for the first time the directionality of these hot electrons and infer the capsule preheat. Data and Monte Carlo calculations indicate that for most experiments the hot electrons are emitted nearly isotropically from the LEH. However, we have found cases where a significant fraction of the generated electrons are emitted in a collimated beam directly towards the capsule poles, where their local energy deposition is up to 10 × higher than the average preheat value and acceptable levels for ICF implosions. The observed "beaming" is consistent with a recently unveiled multibeam stimulated Raman scattering model [P. Michel et al., Phys. Rev. Lett. 115, 055003 (2015)], where laser beams in a cone drive a common plasma wave on axis. Finally, we demonstrate that we can control the amount of generated hot electrons by changing the laser pulse shape and hohlraum plasma.

  13. Nuclear Fusion Research Understanding Plasma-Surface Interactions

    CERN Document Server

    Clark, Robert E.H

    2005-01-01

    It became clear in the early days of fusion research that the effects of the containment vessel (erosion of "impurities") degrade the overall fusion plasma performance. Progress in controlled nuclear fusion research over the last decade has led to magnetically confined plasmas that, in turn, are sufficiently powerful to damage the vessel structures over its lifetime. This book reviews current understanding and concepts to deal with this remaining critical design issue for fusion reactors. It reviews both progress and open questions, largely in terms of available and sought-after plasma-surface interaction data and atomic/molecular data related to these "plasma edge" issues.

  14. Microstructure Filled Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Moore, A. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thomas, C. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reese, T. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-02-24

    We propose replacing the gas fill in a hohlraum with a low average density, variable uniformity 3D printed structure. This creates a bimodal hohlraum which acts like a vacuum hohlraum initially during the picket, but could protect the capsule from glint or direct illumination, and then once expanded, homogenizes to behave like a variable z gas-fill during peak portion of the drive. This is motivated by a two main aims: 1) reduction of the Au bubble velocity to improve inner beam propagation, and 2) the introduction of a low density, high-Z, x-ray converter to improve x-ray production in the hohlraum and uniformity of the radiation field seen by the capsule.

  15. Implosion spectroscopy in Rugby hohlraums on OMEGA

    Science.gov (United States)

    Philippe, Franck; Tassin, Veronique; Bitaud, Laurent; Seytor, Patricia; Reverdin, Charles

    2014-10-01

    The rugby hohlraum concept has been validated in previous experiments on the OMEGA laser facility. This new hohlraum type can now be used as a well-characterized experimental platform to study indirect drive implosion, at higher radiation temperatures than would be feasible at this scale with classical cylindrical hohlraums. Recent experiments have focused on the late stages of implosion and hotspot behavior. The capsules included both a thin buried Titanium tracer layer, 0-3 microns from the inner surface, Argon dopant in the deuterium gas fuel and Germanium doped CH shells, providing a variety of spectral signatures of the plasma conditions in different parts of the target. X-ray spectroscopy and imaging were used to study compression, Rayleigh-Taylor instabilities growth at the inner surface and mix between the shell and gas.

  16. Major minority: energetic particles in fusion plasmas

    Science.gov (United States)

    Breizman, B. N.; Sharapov, S. E.

    2011-05-01

    This paper describes advances made in the field of energetic-particle physics since the topical review of Alfvén eigenmode observations in toroidal plasmas (Wong 1999 Plasma Phys. Control. Fusion 41 R1-R56). The development of plasma confinement scenarios with reversed magnetic shear and significant population of energetic particles, and the development of novel energetic-particle diagnostics were the main milestones in the past decade, and these are the main experimental subjects of this review. The theory of Alfvén cascade eigenmodes in reversed-shear tokamaks and its use in magnetohydrodynamic spectroscopy are presented. Based on experimental observations and nonlinear theory of energetic-particle instabilities in the near-threshold regime, the frequency-sweeping events for spontaneously formed phase-space holes and clumps and the evolution of the fishbone oscillations are described. The multi-mode scenarios of enhanced particle transport are discussed and a brief summary is given of several engaging research topics that are beyond the authors' direct involvement.

  17. The Zero Turbulence Manifold in Fusion Plasmas

    CERN Document Server

    Highcock, E G

    2012-01-01

    The transport of heat that results from turbulence is a major factor limiting the temperature gradient, and thus the performance, of fusion devices. We use nonlinear simulations to show that a toroidal equilibrium scale sheared flow can completely suppress the turbulence across a wide range of flow gradient and temperature gradient values. We demonstrate the existence of a bifurcation across this range whereby the plasma may transition from a low flow gradient and temperature gradient state to a higher flow gradient and temperature gra- dient state. We show further that the maximum temperature gradient that can be reached by such a transition is limited by the existence, at high flow gradient, of subcritical turbulence driven by the parallel velocity gradient (PVG). We use linear simulations and analytic calculations to examine the properties of the transiently growing modes which give rise to this subcritical turbulence, and conclude that there may be a critical value of the ratio of the PVG to the suppressi...

  18. Fundamental studies of fusion plasmas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Aamodt, R.E.

    1998-01-30

    Lodestar has carried out a vigorous research program in the areas of rf, edge plasma and divertor physics, with emphasis largely geared towards improving the understanding and performance of ion-cyclotron heating and current drive (ICRF) systems. Additionally, a research program in the field of edge plasma and divertor modeling was initiated. Theoretical work on high power rf sheath formation for multi-strap rf arrays was developed and benchmarked against recent experimental data from the new JET A2 antennas. Sophisticated modeling tools were employed to understand the sheath formation taking into account realistic three-dimensional antenna geometry. A novel physics explanation of an observed anomaly in the low power loading of antennas was applied to qualitatively interpret data on DIII-D in terms of rf sheaths, and potential applications of the idea to develop a near-field sheath diagnostic were explored. Other rf-wave related topics were also investigated. Full wave ICRF modeling studies were carried out in support of ongoing and planned tokamaks experiments, including the investigation of low frequency plasma heating and current drive regimes for IGNITOR. In a cross-disciplinary study involving both MHD and ICRF physics, ponderomotive feedback stabilization by rf was investigated as a potential means of controlling external kink mode disruptions. In another study, the instability of the ion hybrid wave (IHW) in the presence of fusion alpha particles was studied. In the field of edge plasma and divertor modeling studies, Lodestar began the development of a theory of generalized ballooning and sheath instabilities in the scrape off layer (SOL) of divertor tokamaks. A detailed summary of the technical progress in these areas during the contract period is included, as well as where references to published work can be found. A separate listing of publications, meeting abstracts, and other presentations is also given at the end of this final report.

  19. Final Report on The Theory of Fusion Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Steven C. Cowley

    2008-06-17

    Report describes theoretical research in the theory of fusion plasmas funded under grant DE-FG02-04ER54737. This includes work on: explosive instabilities, plasma turbulence, Alfven wave cascades, high beta (pressure) tokamaks and magnetic reconnection. These studies have lead to abetter understanding of fusion plasmas and in particular the future behavior of ITER. More than ten young researchers were involved in this research -- some were funded under the grant.

  20. Radiation Hydrodynamics Modeling of Hohlraum Energetics

    Science.gov (United States)

    Patel, Mehul V.; Mauche, Christopher W.; Jones, Ogden S.; Scott, Howard A.

    2015-11-01

    Attempts to model the energetics in NIF Hohlraums have been made with varying degrees of success, with discrepancies of 0-25% being reported for the X-ray flux (10-25% for the NIC ignition platform hohlraums). To better understand the cause(s) of these discrepancies, the effects of uncertainties in modeling thermal conduction, laser-plasma interactions, atomic mixing at interfaces, and NLTE kinetics of the high-Z wall plasma must be quantified. In this work we begin by focusing on the NLTE kinetics component. We detail a simulation framework for developing an integrated HYDRA hohlraum model with predefined tolerances for energetics errors due to numerical discretization errors or statistical fluctuations. Within this framework we obtain a model for a converged 1D spherical hohlraum which is then extended to 2D. The new model is used to reexamine physics sensitivities and improve estimates of the energetics discrepancy. Prepared by LLNL under Contract DE-AC52-07NA27344.

  1. Magnetized Plasma Compression for Fusion Energy

    Science.gov (United States)

    Degnan, James; Grabowski, Christopher; Domonkos, Matthew; Amdahl, David

    2013-10-01

    Magnetized Plasma Compression (MPC) uses magnetic inhibition of thermal conduction and enhancement of charge particle product capture to greatly reduce the temporal and spatial compression required relative to un-magnetized inertial fusion (IFE)--to microseconds, centimeters vs nanoseconds, sub-millimeter. MPC greatly reduces the required confinement time relative to MFE--to microseconds vs minutes. Proof of principle can be demonstrated or refuted using high current pulsed power driven compression of magnetized plasmas using magnetic pressure driven implosions of metal shells, known as imploding liners. This can be done at a cost of a few tens of millions of dollars. If demonstrated, it becomes worthwhile to develop repetitive implosion drivers. One approach is to use arrays of heavy ion beams for energy production, though with much less temporal and spatial compression than that envisioned for un-magnetized IFE, with larger compression targets, and with much less ambitious compression ratios. A less expensive, repetitive pulsed power driver, if feasible, would require engineering development for transient, rapidly replaceable transmission lines such as envisioned by Sandia National Laboratories. Supported by DOE-OFES.

  2. Energy coupling in lined hohlraums (HLP1, HLP2, and HLP7)

    Energy Technology Data Exchange (ETDEWEB)

    Kauffman, R.L.; Suter, L.J.; Berger, R.L. [and others

    1996-06-01

    Indirect-drive inertial confinement fusion (ICF) uses high-Z cavities, or hohlraums, to confine x rays for compressing and igniting deuterium-tritium fuel contained in spherical capsules. For laser-driven ICF, the intense laser beams enter the hohlraum through small laser entrance holes (LEHs), heating the high-Z hohlraum walls. The laser-produced radiation heats the unirradiated high-Z walls producing a nearly isotropic radiation environment for spherically compressing the lCF capsule. The radiation flux on the capsule is not completely isotropic, however, because the laser-irradiated area is generally brighter than the surrounding x-ray heated walls and the LEHs do not radiate. Furthermore, the angular distribution of flux on the capsule is time dependent because the unilluminated walls become hotter and more emissive as a function of time, and plasma dynamics cause the laser-irradiated area to move. Symmetric implosions are obtained by dynamically balancing the effects of the LEHs, wall heating, and laser-spot motion.

  3. Vortex stabilized electron beam compressed fusion grade plasma

    Energy Technology Data Exchange (ETDEWEB)

    Hershcovitch, Ady [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-03-19

    Most inertial confinement fusion schemes are comprised of highly compressed dense plasmas. Those schemes involve short, extremely high power, short pulses of beams (lasers, particles) applied to lower density plasmas or solid pellets. An alternative approach could be to shoot an intense electron beam through very dense, atmospheric pressure, vortex stabilized plasma.

  4. Fusion programs in applied plasma physics

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    The objectives of the theoretical science program are: To support the interpretation of present experiments and predict the outcome of future planned experiments; to improve on existing models and codes and validate against experimental results; and to conduct theoretical physics development of advanced concepts with applications for DIII-D and future devices. Major accomplishments in FY91 include the corroboration between theory and experiment on MHD behavior in the second stable regime of operation on DIII-D, and the frequency and mode structure of toroidal Alfven eigenmodes in high beta, shaped plasmas. We have made significant advances in the development of the gyro-Landau fluid approach to turbulence simulation which more accurately models kinetic drive and damping mechanisms. Several theoretical models to explain the bifurcation phenomenon in L- to H-mode transition were proposed providing the theoretical basis for future experimental verification. The capabilities of new rf codes have been upgraded in response to the expanding needs of the rf experiments. Codes are being employed to plan for a fully non-inductive current drive experiment in a high beta, enhanced confinement regime. GA's experimental effort in Applied Physics encompasses two advanced diagnostics essential for the operation of future fusion experiments: Alpha particle diagnostic, and current and density profile diagnostics. This paper discusses research in all these topics.

  5. Collective Thomson scattering capabilities to diagnose fusion plasmas

    DEFF Research Database (Denmark)

    Korsholm, Søren Bang; Bindslev, Henrik; Furtula, Vedran

    2010-01-01

    Collective Thomson scattering (CTS) is a versatile technique for diagnosing fusion plasmas. In particular, experiments on diagnosing the ion temperature and fast ion velocity distribution have been executed on a number of fusion devices. In this article the main aim is to describe the technique...

  6. Simulation of Hohlraum Wall Texture for Improved Performance in Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Isaac Chartrand [Univ. of California, Berkeley, CA (United States); Urbatsch, Todd James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Scott, John Mitchell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-15

    The performance of hohlraums for use in NIF (National Ignition Facility) is explored using Cassio: a LANL produced radiation hydrodynamics code that implements implicit Monte Carlo radiation transport. We examine the effect on blowoff of adding texture to the inside of the hohlraum wall. These new designs are compared in simulation against current designs and the data are analyzed for the possible use of such hohlraums in future high energy density physics experiments.

  7. On Stability of Targets for Plasma Jet Induced Magnetoinertial Fusion

    CERN Document Server

    Samulyak, Roman; Kim, Hyoungekun

    2015-01-01

    The compression and stability of plasma targets for the plasma jet-induced magneto-inertial fusion (PJMIF) have been investigated via large scale simulations using the FronTier code capable of explicit tracking of material interfaces. In the PJMIF concept, a plasma liner, formed by the merger of a large number of radial, highly supersonic plasma jets, implodes on a magnetized plasma target and compresses it to conditions of the fusion ignition. A multi-stage computational approach for simulations of the liner-target interaction and the compression of plasma targets has been developed to minimize computing time. Simulations revealed important features of the target compression process, including instability and disintegration of targets. The non-uniformity of the leading edge of the liner, caused by plasma jets as well as oblique shock waves between them, leads to instabilities during the target compression. By using front tracking, the evolution of targets has been studied in 3-dimensional simulations. Optimi...

  8. Magnetized Target Fusion Propulsion: Plasma Injectors for MTF Guns

    Science.gov (United States)

    Griffin, Steven T.

    2003-01-01

    To achieve increased payload size and decreased trip time for interplanetary travel, a low mass, high specific impulse, high thrust propulsion system is required. This suggests the need for research into fusion as a source of power and high temperature plasma. The plasma would be deflected by magnetic fields to provide thrust. Magnetized Target Fusion (MTF) research consists of several related investigations into these topics. These include the orientation and timing of the plasma guns and the convergence and interface development of the "pusher" plasma. Computer simulations of the gun as it relates to plasma initiation and repeatability are under investigation. One of the items under development is the plasma injector. This is a surface breakdown driven plasma generator designed to function at very low pressures. The performance, operating conditions and limitations of these injectors need to be determined.

  9. Scattered and Reflected Light Polarimetry as a Diagnostic of Multibeam Hohlraum Physics

    Science.gov (United States)

    Turnbull, David

    2015-11-01

    Scattered light provides a window into the complex laser-plasma interactions and hydrodynamics occurring within indirect-drive inertial confinement fusion (ICF) hohlraums. Understanding hohlraum physics is an important part of developing improved targets and increasing the likelihood of ignition. Measurements of the scattered light power and spectrum are routinely made on each cone of beams at the National Ignition Facility (NIF) in order to correct for coupling losses due to laser-plasma instabilities. The additional ability to probe scattered light polarization on a 30° incidence beam was recently added, which has produced a number of discoveries regarding multibeam hohlraum physics. One particularly important insight is that the polarizations of an incident beam and its backscatter are affected by amplitude and phase modulations induced by crossing laser beams. The revised theory describing this optical wave mixing has recently been validated by conducting a two beam pump-probe experiment under carefully controlled conditions. This effect could be utilized more generally to produce ultrafast, damage-resistant, and tunable laser-plasma wave plates, polarizers, or other photonic devices. It also enables remote polarimetry-based probing of plasma conditions such as electron temperature. To extract more quantitative feedback about crossed-beam energy transfer (CBET) from the polarimetry data in ICF experiments at the NIF, the diagnostic has been upgraded to measure the complete Stokes vector with temporal resolution. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  10. Fusion Plasma Physics and ITER - An Introduction (1/4)

    CERN Document Server

    CERN. Geneva

    2011-01-01

    In November 2006, ministers representing the world’s major fusion research communities signed the agreement formally establishing the international project ITER. Sited at Cadarache in France, the project involves China, the European Union (including Switzerland), India, Japan, the Russian Federation, South Korea and the United States. ITER is a critical step in the development of fusion energy: its role is to confirm the feasibility of exploiting magnetic confinement fusion for the production of energy for peaceful purposes by providing an integrated demonstration of the physics and technology required for a fusion power plant. The ITER tokamak is designed to study the “burning plasma” regime in deuterium-tritium (D-T) plasmas by achieving a fusion amplification factor, Q (the ratio of fusion output power to plasma heating input power), of 10 for several hundreds of seconds with a nominal fusion power output of 500MW. It is also intended to allow the study of steady-state plasma operation at Q≥5 by me...

  11. Plasma physics and controlled fusion research during half a century

    Energy Technology Data Exchange (ETDEWEB)

    Lehnert, Bo

    2001-06-01

    A review is given on the historical development of research on plasma physics and controlled fusion. The potentialities are outlined for fusion of light atomic nuclei, with respect to the available energy resources and the environmental properties. Various approaches in the research on controlled fusion are further described, as well as the present state of investigation and future perspectives, being based on the use of a hot plasma in a fusion reactor. Special reference is given to the part of this work which has been conducted in Sweden, merely to identify its place within the general historical development. Considerable progress has been made in fusion research during the last decades. Temperatures above the limit for ignition of self-sustained fusion reactions, i.e. at more than hundred million degrees, have been reached in large experiments and under conditions where the fusion power generation is comparable to the power losses. An energy producing fusion reactor could in principle be realized already today, but it would not become technically and economically efficient when being based on the present state of art. Future international research has therefore to be conducted along broad lines, with necessary ingredients of basic investigations and new ideas.

  12. Fusion plasma physics during half a century

    Energy Technology Data Exchange (ETDEWEB)

    Lehnert, Bo

    1999-08-01

    A review is given on the potentialities of fusion energy with respect to energy production and related environmental problems, the various approaches to controlled thermonuclear fusion, the main problem areas of research, the historical development, the present state of investigations, and future perspectives. This article also presents a personal memorandum of the author. Thereby special reference will be given to part of the research conducted at the Royal Institute of Technology in Stockholm, merely to identify its place within the general historical development. Considerable progress has been made in fusion research during the last decades. In large tokamak experiments temperatures above the ignition limit of about 10{sup 8} K have been reached under break-even conditions where the fusion power generation is comparable to the energy loss. A power producing fusion reactor could in principle be realized already today, but it would not become technically and economically efficient. The future international research programme has therefore to be conducted along broad lines, with necessary ingredients of basis research and new ideas, and also within lines of magnetic confinement being alternative to that of tokamaks.

  13. Indirect drive targets for fusion power

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, Peter A.; Miles, Robin R.

    2016-10-11

    A hohlraum for an inertial confinement fusion power plant is disclosed. The hohlraum includes a generally cylindrical exterior surface, and an interior rugby ball-shaped surface. Windows over laser entrance holes at each end of the hohlraum enclose inert gas. Infrared reflectors on opposite sides of the central point reflect fusion chamber heat away from the capsule. P2 shields disposed on the infrared reflectors help assure an enhanced and more uniform x-ray bath for the fusion fuel capsule.

  14. Hydrodynamic Scaling Analysis of Nuclear Fusion in Hot Plasma

    CERN Document Server

    Kimura, Sachie

    2011-01-01

    Proton beams generated by ultraintense laser pulse irradiations have potential applications in industry and in medicine. However, the laser pulse parameters are currently not optimized for practical applications. We discuss scaling laws of fusion yields generated by laser-plasma interactions. The yields are found to scale as a function of the laser power. The origin of the scaling law in the laser driven fusion yield is derived in terms of hydrodynamical scaling and it is attributed to the laser power dependence of three terms: the reaction rate, the density of the plasma and the pro- jected range of the plasma particle in the medium. The resulting scaling relations have a powerful predictive power that enables estimating the fusion yield for a nuclear reaction which has not been investigated by means of the laser accelerated ion beams.

  15. Response of nickel surface to pulsed fusion plasma radiations

    Science.gov (United States)

    Niranjan, Ram; Rout, R. K.; Srivastava, R.; Chakravarthy, Y.; Patel, N. N.; Alex, P.; Gupta, Satish C.

    2014-04-01

    Nickel based alloys are being projected as suitable materials for some components of the next generation fusion reactor because of compatible thermal, electrical and mechanical properties. Pure nickel material is tested here for possibility of similar application purpose. Nickel samples (> 99.5 % purity) are exposed here to plasma radiations produced due to D-D fusion reaction inside an 11.5 kJ plasma focus device. The changes in the physical properties of the nickel surface at microscopic level which in turn change the mechanical properties are analyzed using scanning electron microscope, optical microscope, glancing incident X-ray diffractometer and Vicker's hardness gauge. The results are reported here.

  16. Transport properties of inertial confinement fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Issanova, M.K.; Kodanova, S.K.; Ramazanov, T.S. [IETP, Al-Farabi Kazakh National University, Almaty (Kazakhstan); Hoffmann, D.H.H. [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany)

    2016-06-15

    In this paper the transport properties of non-isothermal dense deuterium-tritium plasmas were studied. Based on the effective interaction potentials between particles, the Coulomb logarithm for a two-temperature nonisothermal dense plasma was obtained. These potentials take into consideration long-range multi-particle screening effects and short-range quantum-mechanical effects in two-temperature plasmas. Transport processes in such plasmas were studied using the Coulomb logarithm. The obtained results were compared with the theoretical works of other authors and with the results of molecular dynamics simulations. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Physics of laser fusion. Vol. I. Theory of the coronal plasma in laser-fusion targets

    Energy Technology Data Exchange (ETDEWEB)

    Max, C.E.

    1981-12-01

    This monograph deals with the physics of the coronal region in laser fusion targets. The corona consists of hot plasma which has been evaporated from the initially solid target during laser heating. It is in the corona that the laser light is absorbed by the target, and the resulting thermal energy is conducted toward cold high-density regions, where ablation occurs. The topics to be discussed are theoretical mechanisms for laser light absorption and reflection, hot-electron production, and the physics of heat conduction in laser-produced plasmas. An accompanying monograph by H. Ahlstrom (Vol.II) reviews the facilities, diagnostics, and data from recent laser fusion experiments.

  18. Additional Beta due to Fast Fusion Products in D-3He Fusion Plasma

    Institute of Scientific and Technical Information of China (English)

    DENG Bai-Quan(邓柏权); G.A.Emmert; PENG Li-Lin(彭利林)

    2003-01-01

    An analytical formula for the additional beta due to fast fusion-born ions is derived by using the slowing-down approximation from the Fokker-Planck equation under the assumption of negligible loss term. It is found that the fast ion beta in a D-3 He fusion plasma at a typical temperature of 55 ke V is about 20% of the thermal beta,which is the same ratio as that obtained in a D-T plasma at 20keV.

  19. Transport studies in fusion plasmas: Perturbative experiments

    NARCIS (Netherlands)

    Cardozo, N. L.

    1998-01-01

    By inducing in a small temperature perturbation in a plasma in a steady state one can determine the conductive and convective components of the heat flux, and the associated thermal diffusivity and convection velocity. The same can be done for the density, and in principle also other plasma paramete

  20. Laser-plasma interactions relevant to Inertial Confinement Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, K.B.

    1998-11-02

    Research into laser-driven inertial confinement fusion is now entering a critical juncture with the construction of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). Many of the remaining unanswered questions concerning NIF involve interactions between lasers and plasmas. With the eventual goal of fusion power in mind, laser-plasma interactions relevant to laser fusion schemes is an important topic in need of further research. This work experimentally addresses some potential shortcuts and pitfalls on the road to laser-driven fusion power. Current plans on NIF have 192 laser beams directed into a small cylindrical cavity which will contain the fusion fuel; to accomplish this the beams must cross in the entrance holes, and this intersection will be in the presence of outward-flowing plasma. To investigate the physics involved, interactions of crossing laser beams in flowing plasmas are investigated with experiments on the Nova laser facility at LLNL. It was found that in a flowing plasma, energy is transferred between two crossing laser beams, and this may have deleterious consequences for energy balance and ignition in NIF. Possible solutions to this problem are presented. A recently-proposed alternative to standard laser-driven fusion, the ''fast ignitor'' concept, is also experimentally addressed in this dissertation. Many of the laser-plasma interactions necessary for the success of the fast ignitor have not previously been explored at the relevant laser intensities. Specifically, the transfer of high-intensity laser energy to electrons at solid-target interfaces is addressed. 20-30% conversion efficiencies into forward-propagated electrons were measured, along with an average electron energy that varied with the type of target material. The directionality of the electrons was also measured, revealing an apparent beaming of the highest energy electrons. This work was extended to various intensities and

  1. Passive Spectroscopic Diagnostics for Magnetically-confined Fusion Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Stratton, B. C.; Biter, M.; Hill, K. W.; Hillis, D. L.; Hogan, J. T.

    2007-07-18

    Spectroscopy of radiation emitted by impurities and hydrogen isotopes plays an important role in the study of magnetically-confined fusion plasmas, both in determining the effects of impurities on plasma behavior and in measurements of plasma parameters such as electron and ion temperatures and densities, particle transport, and particle influx rates. This paper reviews spectroscopic diagnostics of plasma radiation that are excited by collisional processes in the plasma, which are termed 'passive' spectroscopic diagnostics to distinguish them from 'active' spectroscopic diagnostics involving injected particle and laser beams. A brief overview of the ionization balance in hot plasmas and the relevant line and continuum radiation excitation mechanisms is given. Instrumentation in the soft X-ray, vacuum ultraviolet, ultraviolet, visible, and near-infrared regions of the spectrum is described and examples of measurements are given. Paths for further development of these measurements and issues for their implementation in a burning plasma environment are discussed.

  2. The near vacuum hohlraum campaign at the NIF: A new approach

    Science.gov (United States)

    Le Pape, S.; Berzak Hopkins, L. F.; Divol, L.; Meezan, N.; Turnbull, D.; Mackinnon, A. J.; Ho, D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E.; Benedetti, L. R.; Nagel, S.; Biener, J.; Callahan, D. A.; Yeamans, C.; Michel, P.; Schneider, M.; Kozioziemski, B.; Ma, T.; Macphee, A. G.; Haan, S.; Izumi, N.; Hatarik, R.; Sterne, P.; Celliers, P.; Ralph, J.; Rygg, R.; Strozzi, D.; Kilkenny, J.; Rosenberg, M.; Rinderknecht, H.; Sio, H.; Gatu-Johnson, M.; Frenje, J.; Petrasso, R.; Zylstra, A.; Town, R.; Hurricane, O.; Nikroo, A.; Edwards, M. J.

    2016-05-01

    The near vacuum campaign on the National Ignition Facility has concentrated its efforts over the last year on finding the optimum target geometry to drive a symmetric implosion at high convergence ratio (30×). As the hohlraum walls are not tamped with gas, the hohlraum is filling with gold plasma and the challenge resides in depositing enough energy in the hohlraum before it fills up. Hohlraum filling is believed to cause symmetry swings late in the pulse that are detrimental to the symmetry of the hot spot at high convergence. This paper describes a series of experiments carried out to examine the effect of increasing the distance between the hohlraum wall and the capsule (case to capsule ratio) on the symmetry of the hot spot. These experiments have shown that smaller Case to Capsule Ratio (CCR of 2.87 and 3.1) resulted in oblate implosions that could not be tuned round. Larger CCR (3.4) led to a prolate implosion at convergence 30× implying that inner beam propagation at large CCR is not impeded by the expanding hohlraum plasma. A Case to Capsule ratio of 3.4 is a promising geometry to design a round implosion but in a smaller hohlraum where the hohlraum losses are lower, enabling a wider cone fraction range to adjust symmetry.

  3. The near vacuum hohlraum campaign at the NIF: A new approach

    Energy Technology Data Exchange (ETDEWEB)

    Le Pape, S.; Berzak Hopkins, L. F.; Divol, L.; Meezan, N.; Turnbull, D.; Ho, D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E.; Benedetti, L. R.; Nagel, S.; Biener, J.; Callahan, D. A.; Yeamans, C.; Michel, P.; Schneider, M.; Kozioziemski, B.; Ma, T.; Macphee, A. G. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2016-05-15

    The near vacuum campaign on the National Ignition Facility has concentrated its efforts over the last year on finding the optimum target geometry to drive a symmetric implosion at high convergence ratio (30×). As the hohlraum walls are not tamped with gas, the hohlraum is filling with gold plasma and the challenge resides in depositing enough energy in the hohlraum before it fills up. Hohlraum filling is believed to cause symmetry swings late in the pulse that are detrimental to the symmetry of the hot spot at high convergence. This paper describes a series of experiments carried out to examine the effect of increasing the distance between the hohlraum wall and the capsule (case to capsule ratio) on the symmetry of the hot spot. These experiments have shown that smaller Case to Capsule Ratio (CCR of 2.87 and 3.1) resulted in oblate implosions that could not be tuned round. Larger CCR (3.4) led to a prolate implosion at convergence 30× implying that inner beam propagation at large CCR is not impeded by the expanding hohlraum plasma. A Case to Capsule ratio of 3.4 is a promising geometry to design a round implosion but in a smaller hohlraum where the hohlraum losses are lower, enabling a wider cone fraction range to adjust symmetry.

  4. Inertial Confinement Fusion quarterly report, January--March 1995. Volume 5, No. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    The ICF quarterly report is published by the Inertial Confinement Fusion Program at the Lawrence Livermore National Laboratory. Topics included this quarter include: the role of the National Ignition Facility in the development of Inertial Confinement Fusion, laser-plasma interactions in large gas-filled hohlraums, evolution of solid-state induction modulators for a heavy-ion recirculator, the National Ignition Facility project, and terminal-level relaxation in Nd-doped laser material.

  5. High-Gain High-Field Fusion Plasma

    Science.gov (United States)

    Li, Ge

    2015-01-01

    A Faraday wheel (FW)—an electric generator of constant electrical polarity that produces huge currents—could be implemented in an existing tokamak to study high-gain high-field (HGHF) fusion plasma, such as the Experimental Advanced Superconducting Tokamak (EAST). HGHF plasma can be realized in EAST by updating its pulsed-power system to compress plasma in two steps by induction fields; high gains of the Lawson trinity parameter and fusion power are both predicted by formulating the HGHF plasma. Both gain rates are faster than the decrease rate of the plasma volume. The formulation is checked by earlier ATC tests. Good agreement between theory and tests indicates that scaling to over 10 T at EAST may be possible by two-step compressions with a compression ratio of the minor radius of up to 3. These results point to a quick new path of fusion plasma study, i.e., simulating the Sun by EAST. PMID:26507314

  6. Alpha Heating and Burning Plasmas in Inertial Confinement Fusion

    Science.gov (United States)

    Betti, R.; Christopherson, A. R.; Bose, A.; Woo, K. M.

    2016-05-01

    Assessing the degree to which fusion alpha particles contribute to the fusion yield is essential to understanding the onset of the thermal runaway process of thermonuclear ignition. It is shown that in inertial confinement fusion, the yield enhancement due to alpha particle heating (before ignition occurs) depends on the generalized Lawson parameter that can be inferred from experimental observables. A universal curve valid for arbitrary laser-fusion targets shows the yield amplification due to alpha heating for a given value of the Lawson parameter. The same theory is used to determine the onset of the burning plasma regime when the alpha heating exceeds the compression work. This result can be used to assess the performance of current ignition experiments at the National Ignition Facility.

  7. Lithium ion beam driven hohlraums for PBFA II

    Energy Technology Data Exchange (ETDEWEB)

    Dukart, R.J.

    1994-05-06

    In our light ion inertial confinement fusion (ICF) program, fusion capsules are driven with an intense x-ray radiation field produced when an intense beam of ions penetrates a radiation case and deposits energy in a foam x-ray conversion region. A first step in the program is to generate and measure these intense fields on the Particle Beam Fusion Accelerator II (PBFA II). Our goal is to generate a 100-eV radiation temperature in lithium ion beam driven hohlraums, the radiation environment which will provide the initial drive temperature for ion beam driven implosion systems designed to achieve high gain. In this paper, we describe the design of such hohlraum targets and their predicted performance on PBFA II as we provide increasing ion beam intensities.

  8. Lithium-based surfaces controlling fusion plasma behavior at the plasma-material interfacea)

    Science.gov (United States)

    Allain, Jean Paul; Taylor, Chase N.

    2012-05-01

    The plasma-material interface and its impact on the performance of magnetically confined thermonuclear fusion plasmas are considered to be one of the key scientific gaps in the realization of nuclear fusion power. At this interface, high particle and heat flux from the fusion plasma can limit the material's lifetime and reliability and therefore hinder operation of the fusion device. Lithium-based surfaces are now being used in major magnetic confinement fusion devices and have observed profound effects on plasma performance including enhanced confinement, suppression and control of edge localized modes (ELM), lower hydrogen recycling and impurity suppression. The critical spatial scale length of deuterium and helium particle interactions in lithium ranges between 5-100 nm depending on the incident particle energies at the edge and magnetic configuration. Lithium-based surfaces also range from liquid state to solid lithium coatings on a variety of substrates (e.g., graphite, stainless steel, refractory metal W/Mo/etc., or porous metal structures). Temperature-dependent effects from lithium-based surfaces as plasma facing components (PFC) include magnetohydrodynamic (MHD) instability issues related to liquid lithium, surface impurity, and deuterium retention issues, and anomalous physical sputtering increase at temperatures above lithium's melting point. The paper discusses the viability of lithium-based surfaces in future burning-plasma environments such as those found in ITER and DEMO-like fusion reactor devices.

  9. Numerical Experiments Providing New Insights into Plasma Focus Fusion Devices

    Directory of Open Access Journals (Sweden)

    Sing Lee

    2010-04-01

    Full Text Available Recent extensive and systematic numerical experiments have uncovered new insights into plasma focus fusion devices including the following: (1 a plasma current limitation effect, as device static inductance is reduced towards very small values; (2 scaling laws of neutron yield and soft x-ray yield as functions of storage energies and currents; (3 a global scaling law for neutron yield as a function of storage energy combining experimental and numerical data showing that scaling deterioration has probably been interpreted as neutron ‘saturation’; and (4 a fundamental cause of neutron ‘saturation’. The ground-breaking insights thus gained may completely change the directions of plasma focus fusion research.

  10. Nonlinear laser-plasma interaction in magnetized liner inertial fusion

    Science.gov (United States)

    Geissel, Matthias; Awe, T. J.; Bliss, D. E.; Campbell, M. E.; Gomez, M. R.; Harding, E.; Harvey-Thompson, A. J.; Hansen, S. B.; Jennings, C.; Kimmel, M. W.; Knapp, P.; Lewis, S. M.; McBride, R. D.; Peterson, K.; Schollmeier, M.; Scoglietti, D. J.; Sefkow, A. B.; Shores, J. E.; Sinars, D. B.; Slutz, S. A.; Smith, I. C.; Speas, C. S.; Vesey, R. A.; Porter, J. L.

    2016-03-01

    Sandia National Laboratories is pursuing a variation of Magneto-Inertial Fusion called Magnetized Liner Inertial Fusion, or MagLIF. The MagLIF approach requires magnetization of the deuterium fuel, which is accomplished by an initial external B-Field and laser-driven pre-heat. While magnetization is crucial to the concept, it is challenging to couple sufficient energy to the fuel, since laser-plasma instabilities exist, and a compromise between laser spot size, laser entrance window thickness, and fuel density must be found. Nonlinear processes in laser plasma interaction, or laser-plasma instabilities (LPI), complicate the deposition of laser energy by enhanced absorption, backscatter, filamentation and beam-spray. Key LPI processes are determined, and mitigation methods are discussed. Results with and without improvement measures are presented.

  11. Transport Studies in Fusion Plasmas - Perturbative Experiments

    NARCIS (Netherlands)

    Cardozo, N. J. L.

    1994-01-01

    By subjecting a plasma in steady state to small perturbations and measuring the response, it is possible to determine elements of the matrix of transport coefficients. Experimentally this is difficult, and results are mainly limited to tranpsport driven by the pressure and temperature gradients. Imp

  12. Transport studies in fusion plasmas: Perturbative experiments

    NARCIS (Netherlands)

    Cardozo, N. J. L.

    1996-01-01

    By subjecting a plasma in steady state to small perturbations and measuring the response, it is possible to determine elements of the matrix of transport coefficients. Experimentally this is difficult, and results are mainly limited to tranpsport driven by the pressure and temperature gradients. Imp

  13. Fusion plasma experiments on TFTR: A 20 year retrospective*

    Energy Technology Data Exchange (ETDEWEB)

    Hawryluk, R. J.; Batha, S.; Blanchard, W.; Beer, M.; Bell, M. G.; Bell, R. E.; Berk, H.; Bernabei, S.; Bitter, M.; Breizman, B.; Bretz, N. L; Budny, R.; Bush, C. E.; Callen, J.; Camp, R.; Cauffman, S.; Chang, Z.; Cheng, C. Z.; Darrow, D. S.; Dendy, R. O.; Dorland, W.; Duong, H.; Efthimion, P. C.; Ernst, D.; Fisch, N. J.; Fisher, R.; Fonck, R. J.; Fredrickson, E. D.; Fu, G. Y.; Furth, H. P.; Gorelenkov, N. N.; Grek, B.; Grisham, L. R.; Hammett, G. W.; Hanson, G. R.; Herrmann, H. W.; Herrmann, M. C.; Hill, K. W.; Hogan, J.; Hosea, J. C.; Houlberg, W. A.; Hughes, M.; Hulse, R. A.; Jassby, D. L.; Jobes, F. C.; Johnson, D. W.; Kaita, R.; Kaye, S.; Kim, J. S.; Kissick, M.; Krasilnikov, A. V.; Kugel, H.; Kumar, A.; Leblanc, B.; Levinton, F. M.; Ludescher, C.; Majeski, R. P.; Manickam, J.; Mansfield, D. K.; Mazzucato, E.; McChesney, J.; McCune, D. C.; McGuire, K. M.; Meade, D. M.; Medley, S. S.; Mika, R.; Mikkelsen, D. R.; Mirnov, S. V.; Mueller, D.; Nagy, A.; Navratil, G. A.; Nazikian, R.; Okabayashi, M.; Park, H. K.; Park, W.; Paul, S. F.; Pearson, G.; Petrov, M. P.; Phillips, C. K.; Phillips, M.; Ramsey, A. T.; Redi, M. H.; Rewoldt, G.; Reznik, S.; Roquemore, A. L.; Rogers, J.; Ruskov, E.; Sabbagh, S. A.; Sasao, M.; Schilling, G.; Schivell, J.; Schmidt, G. L.; Scott, S. D.; Semenov, I.; Skinner, C. H.; Stevenson, T.; Stratton, B. C.; Strachan, J. D.; Stodiek, W.; Synakowski, E.; Takahashi, H.; Tang, W.; Taylor, G.; Thompson, M. E.; Von Goeler, S.; Von Halle, A.; Walters, R. T.; White, R.; Wieland, R. M.; Williams, M.; Wilson, J. R.; Wong, K. L.; Wurden, G. A.; Yamada, M.; Yavorski, V.; Young, K. M.; Zakharov, L.; Zarnstorff, M. C.; Zweben, S. J. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    1998-01-01

    The Tokamak Fusion Test Reactor (TFTR) (R. J. Hawryluk, to be published in Rev. Mod. Phys.) experiments on high-temperature plasmas, that culminated in the study of deuterium–tritium D–T plasmas containing significant populations of energetic alpha particles, spanned over two decades from conception to completion. During the design of TFTR, the key physics issues were magnetohydrodynamic (MHD) equilibrium and stability, plasma energy transport, impurity effects, and plasma reactivity. Energetic particle physics was given less attention during this phase because, in part, of the necessity to address the issues that would create the conditions for the study of energetic particles and also the lack of diagnostics to study the energetic particles in detail. The worldwide tokamak program including the contributions from TFTR made substantial progress during the past two decades in addressing the fundamental issues affecting the performance of high-temperature plasmas and the behavior of energetic particles. The progress has been the result of the construction of new facilities, which enabled the production of high-temperature well-confined plasmas, development of sophisticated diagnostic techniques to study both the background plasma and the resulting energetic fusion products, and computational techniques to both interpret the experimental results and to predict the outcome of experiments. © 1998 American Institute of Physics.

  14. Energetic particle instabilities in fusion plasmas

    CERN Document Server

    Sharapov, S E; Berk, H L; Borba, D N; Breizman, B N; Challis, C D; Classen, I G J; Edlund, E M; Eriksson, J; Fasoli, A; Fredrickson, E D; Fu, G Y; Garcia-Munoz, M; Gassner, T; Ghantous, K; Goloborodko, V; Gorelenkov, N N; Gryaznevich, M P; Hacquin, S; Heidbrink, W W; Hellesen, C; Kiptily, V G; Kramer, G J; Lauber, P; Lilley, M K; Lisak, M; Nabais, F; Nazikian, R; Nyqvist, R; Osakabe, M; von Thun, C Perez; Pinches, S D; Podesta, M; Porkolab, M; Shinohara, K; Schoepf, K; Todo, Y; Toi, K; Van Zeeland, M A; Voitsekhovich, I; White, R B; Yavorskij, V; TG, ITPA EP; Contributors, JET-EFDA

    2013-01-01

    Remarkable progress has been made in diagnosing energetic particle instabilities on present-day machines and in establishing a theoretical framework for describing them. This overview describes the much improved diagnostics of Alfven instabilities and modelling tools developed world-wide, and discusses progress in interpreting the observed phenomena. A multi-machine comparison is presented giving information on the performance of both diagnostics and modelling tools for different plasma conditions outlining expectations for ITER based on our present knowledge.

  15. Surface modifications of fusion reactor relevant materials on exposure to fusion grade plasma in plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Niranjan, Ram, E-mail: niranjan@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K.; Srivastava, R. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Chakravarthy, Y. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mishra, P. [Materials Processing Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C.; Gupta, Satish C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2015-11-15

    Graphical abstract: - Highlights: • Exposure of materials (W, Ni, SS, Mo and Cu) to fusion plasma in a plasma focus device. • The erosion and the formations of blisters, pores, craters, micro-cracks after irradiation. • The structural phase transformation in the SS sample after irradiation. • The surface layer alloying of the samples with the plasma focus anode material. - Abstract: An 11.5 kJ plasma focus (PF) device was used here to irradiate materials with fusion grade plasma. The surface modifications of different materials (W, Ni, stainless steel, Mo and Cu) were investigated using various available techniques. The prominent features observed through the scanning electron microscope on the sample surfaces were erosions, cracks, blisters and craters after irradiations. The surface roughness of the samples increased multifold after exposure as measured by the surface profilometer. The X-ray diffraction analysis indicated the changes in the microstructures and the structural phase transformation in surface layers of the samples. We observed change in volumes of austenite and ferrite phases in the stainless steel sample. The energy dispersive X-ray spectroscopic analysis suggested alloying of the surface layer of the samples with elements of the PF anode. We report here the comparative analysis of the surface damages of materials with different physical, thermal and mechanical properties. The investigations will be useful to understand the behavior of the perspective materials for future fusion reactors (either in pure form or in alloy) over the long operations.

  16. Understanding plasma facing surfaces in magnetic fusion devices

    Science.gov (United States)

    Skinner, C. H.; Capece, A. M.; Koel, B. E.; Roszell, J. P.

    2013-09-01

    The plasma-material interface is recognized to be the most critical challenge in the realization of fusion energy. Liquid metals offer a self-healing, renewable interface that bypasses present issues with solid, neutron-damaged materials such as tungsten. Lithium in particular has dramatically improved plasma performance in many tokamaks through a reduction of hydrogen recycling. However the detailed chemical composition and properties of the top few nm that interact with the plasma are often obscure. Surface analysis has proven to be a key tool in semiconductor processing and a new laboratory has been established at PPPL to apply surface science techniques to plasma facing materials. We have shown that lithiated PFC surfaces in tokamaks will likely be oxidized during the intershot interval. Present work is focused on deuterium uptake of solid and liquid metals for plasma density control and sub-micron scale wetting of liquid metals on their substrates. The long-term goal is to provide a material database for designing liquid metal plasma facing components for tokamaks such as National Spherical Torus Experiment-Upgrade (NSTX-U) and Fusion Nuclear Science Facility-ST (FNSF-ST). Support was provided through DOE-PPPL Contract Number is DE-AC02-09CH11466.

  17. Aneutronic Fusion in a Degenerate Plasma

    Energy Technology Data Exchange (ETDEWEB)

    S. Son; N.J. Fisch

    2004-09-03

    In a Fermi-degenerate plasma, the electronic stopping of a slow ion is smaller than that given by the classical formula, because some transitions between the electron states are forbidden. The bremsstrahlung losses are then smaller, so that the nuclear burning of an aneutronic fuel is more efficient. Consequently, there occurs a parameter regime in which self-burning is possible. Practical obstacles in this regime that must be overcome before net energy can be realized include the compression of the fuel to an ultra dense state and the creation of a hot spot.

  18. Magnetohydrodynamic waves in fusion and astrophysical plasmas.

    Science.gov (United States)

    Goedbloed, J. P.

    Macroscopic plasma dynamics in both controlled thermonuclear confinement machines and in the atmospheres of X-ray emitting stars is described by the equations of magnetohydrodynamics. This provides a vast area of overlapping research activities which is presently actively pursued. In this lecture the author concentrates on some important differences in the dynamics of the two confined plasma systems related to the very different geometries that are encountered and, thus, the role of the different boundary conditions that have to be posed. As a result, the basic MHD waves in a tokamak are quite different from those found in a solar magnetic flux tube. The result is that, whereas the three well-known MHD waves can be traced stepwise in the curved geometry of a tokamak, their separate existence is eliminated right from the start in a line-tied coronal loop because line-tying in general conflicts with the phase relationships between the vector components of the three velocity fields. The consequences are far-reaching, viz. completely different resonant frequencies and continuous spectra, absence of rational magnetic surfaces, and irrelevance of local marginal stability theory for coronal magnetic loops.

  19. Plasma Heating and Current Drive for Fusion Reactors

    Science.gov (United States)

    Holtkamp, Norbert

    2010-02-01

    ITER (in Latin ``the way'') is designed to demonstrate the scientific and technological feasibility of fusion energy. Fusion is the process by which two light atomic nuclei combine to form a heavier one and thus release energy. In the fusion process two isotopes of hydrogen - deuterium and tritium - fuse together to form a helium atom and a neutron. Thus fusion could provide large scale energy production without greenhouse effects; essentially limitless fuel would be available all over the world. The principal goals of ITER are to generate 500 megawatts of fusion power for periods of 300 to 500 seconds with a fusion power multiplication factor, Q, of at least 10. Q >= 10 (input power 50 MW / output power 500 MW). In a Tokamak the definition of the functionalities and requirements for the Plasma Heating and Current Drive are relevant in the determination of the overall plant efficiency, the operation cost of the plant and the plant availability. This paper summarise these functionalities and requirements in perspective of the systems under construction in ITER. It discusses the further steps necessary to meet those requirements. Approximately one half of the total heating will be provided by two Neutral Beam injection systems at with energy of 1 MeV and a beam power of 16 MW into the plasma. For ITER specific test facility is being build in order to develop and test the Neutral Beam injectors. Remote handling maintenance scheme for the NB systems, critical during the nuclear phase of the project, will be developed. In addition the paper will give an overview over the general status of ITER. )

  20. Nuclear Fusion Effects Induced in Intense Laser-Generated Plasmas

    Directory of Open Access Journals (Sweden)

    Lorenzo Torrisi

    2013-01-01

    Full Text Available Deutered polyethylene (CD2n thin and thick targets were irradiated in high vacuum by infrared laser pulses at 1015W/cm2 intensity. The high laser energy transferred to the polymer generates plasma, expanding in vacuum at supersonic velocity, accelerating hydrogen and carbon ions. Deuterium ions at kinetic energies above 4 MeV have been measured by using ion collectors and SiC detectors in time-of-flight configuration. At these energies the deuterium–deuterium collisions may induce over threshold fusion effects, in agreement with the high D-D cross-section valuesaround 3 MeV energy. At the first instants of the plasma generation, during which high temperature, density and ionacceleration occur, the D-D fusions occur as confirmed by the detection of mono-energetic protonsand neutrons with a kinetic energy of 3.0 MeV and 2.5 MeV, respectively, produced by the nuclear reaction. The number of fusion events depends strongly on the experimental set-up, i.e. on the laser parameters (intensity, wavelength, focal spot dimension, target conditions (thickness, chemical composition, absorption coefficient, presence of secondary targets and used geometry (incidence angle, laser spot, secondary target positions.A number of D-D fusion events of the order of 106÷7 per laser shot has been measured.

  1. Baseline high heat flux and plasma facing materials for fusion

    Science.gov (United States)

    Ueda, Y.; Schmid, K.; Balden, M.; Coenen, J. W.; Loewenhoff, Th.; Ito, A.; Hasegawa, A.; Hardie, C.; Porton, M.; Gilbert, M.

    2017-09-01

    In fusion reactors, surfaces of plasma facing components (PFCs) are exposed to high heat and particle flux. Tungsten and Copper alloys are primary candidates for plasma facing materials (PFMs) and coolant tube materials, respectively, mainly due to high thermal conductivity and, in the case of tungsten, its high melting point. In this paper, recent understandings and future issues on responses of tungsten and Cu alloys to fusion environments (high particle flux (including T and He), high heat flux, and high neutron doses) are reviewed. This review paper includes; Tritium retention in tungsten (K. Schmid and M. Balden), Impact of stationary and transient heat loads on tungsten (J.W. Coenen and Th. Loewenhoff), Helium effects on surface morphology of tungsten (Y. Ueda and A. Ito), Neutron radiation effects in tungsten (A. Hasegawa), and Copper and copper alloys development for high heat flux components (C. Hardie, M. Porton, and M. Gilbert).

  2. Response of nickel surface to pulsed fusion plasma radiations

    Energy Technology Data Exchange (ETDEWEB)

    Niranjan, Ram, E-mail: niranjan@barc.gov.in; Rout, R. K., E-mail: niranjan@barc.gov.in; Srivastava, R., E-mail: niranjan@barc.gov.in; Gupta, Satish C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Chakravarthy, Y. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Patel, N. N. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Alex, P. [Materials Processing Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24

    Nickel based alloys are being projected as suitable materials for some components of the next generation fusion reactor because of compatible thermal, electrical and mechanical properties. Pure nickel material is tested here for possibility of similar application purpose. Nickel samples (> 99.5 % purity) are exposed here to plasma radiations produced due to D-D fusion reaction inside an 11.5 kJ plasma focus device. The changes in the physical properties of the nickel surface at microscopic level which in turn change the mechanical properties are analyzed using scanning electron microscope, optical microscope, glancing incident X-ray diffractometer and Vicker's hardness gauge. The results are reported here.

  3. Isotope Effects of Solid Hydrogenic Pellet Ablation in Fusion Plasma

    Institute of Scientific and Technical Information of China (English)

    PENGLilin; DENGBaiquan; YANJiancheng; WANGXiaoyu

    2003-01-01

    The isotope effects of ablation processes in fusion plasma for five combinations of solid isotopic hydrogenic pellets H2, HD, D2,DT, T2 have been first time studied. The resuits show that the modifications caused by isotope effects for pellet erosion speeds range from 1 for hydrogen pellet down to 0. 487 for tritium pellet and are not negligible in ablation rate calculations. These effects lead to deeper mass deposition and improved core fueling efficiency.

  4. Ignition Regime for Fusion in a Degenerate Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Son, S.; Fisch, N.J.

    2005-12-01

    We identify relevant parameter regimes in which aneutronic fuels can undergo fusion ignition in hot-ion degenerate plasma. Because of relativistic effects and partial degeneracy, the self-sustained burning regime is considerably larger than previously calculated. Inverse bremsstrahlung plays a major role in containing the reactor energy. We solve the radiation transfer equation and obtain the contribution to the heat conductivity from inverse bremsstrahlung.

  5. The mathematical theory of reduced MHD models for fusion plasmas

    OpenAIRE

    Guillard, Hervé

    2015-01-01

    The derivation of reduced MHD models for fusion plasma is here formulated as a special instance of the general theory of singular limit of hyperbolic system of PDEs with large operator. This formulation allows to use the general results of this theory and to prove rigorously that reduced MHD models are valid approximations of the full MHD equations. In particular, it is proven that the solutions of the full MHD system converge to the solutions of an appropriate reduced model.

  6. Reflectometry techniques for density profile measurements on fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Laviron, C. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Donne, A.J.H. [Associatie Euratom-FOM, Nieuwegein (Netherlands). FOM-Instituut voor Plasmafysica; Manso, M.E. [Instituto Superior Tecnico, Lisbon (Portugal). Lab. de Quimica Organica; Sanchez, J. [EURATOM-CIEMAT for Fusion Association, Madrid (Spain)

    1996-03-01

    Reflectometry applied to the measurement of density profiles on fusion plasmas has been subject to many recent developments. After a brief reminder of the principles of reflectometry, the theoretical accuracy of reflectometry measurements is discussed. The main difficulties limiting the performance, namely the plasma fluctuations and the quality of the transmission lines, are analysed. The different techniques used for reflectometry are then presented. The present status and achievements of actual implementations of these techniques are shown, with an analysis of their respective limitations and merits, as well as foreseen developments. (author). 70 refs.

  7. Understanding of Edge Plasmas in Magnetic Fusion Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    Rognlien, T

    2004-11-01

    A limited overview is given of the theoretical understanding of edge plasmas in fusion devices. This plasma occupies the thin region between the hot core plasma and material walls in magnetically confinement configurations. The region is often formed by a change in magnetic topology from close magnetic field lines (i.e., the core region) and open field lines that contact material surfaces (i.e., the scrape-off layer [SOL]), with the most common example being magnetically diverted tokamaks. The physics of this region is determined by the interaction of plasma with neutral gas in the presence of plasma turbulence, with impurity radiation being an important component. Recent advances in modeling strong, intermittent micro-turbulent edge-plasma transport is given, and the closely coupled self-consistent evolution of the edge-plasma profiles in tokamaks. In addition, selected new results are given for the characterization of edge-plasmas behavior in the areas of edge-pedestal relaxation and SOL transport via Edge-Localize Modes (ELMs), impurity formation including dust, and magnetic field-line stochasticity in tokamaks.

  8. Laser-plasma interactions in NIF-scale plasmas (HLP5 and HLP6)

    Energy Technology Data Exchange (ETDEWEB)

    MacGowan, B.; Berger, R.; Fernandez, J. [Los Alamos National Lab., NM (United States)

    1996-06-01

    The understanding of laser-plasma interactions in ignition-scale inertial confinement fusion (ICF) hohlraum targets is important for the success of the proposed National Ignition Facility (NIF). The success of an indirect-drive ICF ignition experiment depends on the ability to predict and control the history and spatial distribution of the x-radiation produced by the laser beams that are absorbed by the inside of the hohlraum wall. Only by controlling the symmetry of this x-ray drive is it possible to obtain the implosion symmetry in the fusion pellet necessary for ignition. The larger hohlraums and longer time scales required for ignition-scale targets result in the presence of several millimeters of plasma (electron density n{sub e} {approximately} 0.1 n{sub c} {approximately} 10{sup 21} cm{sup {minus}3}), through which the 3{omega} (351-nm) laser beams must propagate before they are absorbed at the hohlraum wall. Hydrodynamic simulations show this plasma to be very uniform [density-gradient scalelength L{sub n} = n{sub e}(dn{sub e}/dx){sup {minus}1}{approximately} 2mm] and to exhibit low velocity gradients [velocity-gradient scale-length L{sub v} = c{sub s}(dv/dx){sup {minus}1} > 6 mm].

  9. Experimental Demonstration of X-Ray Drive Enhancement with Rugby-Shaped Hohlraums

    Science.gov (United States)

    Philippe, F.; Casner, A.; Caillaud, T.; Landoas, O.; Monteil, M. C.; Liberatore, S.; Park, H. S.; Amendt, P.; Robey, H.; Sorce, C.; Li, C. K.; Seguin, F.; Rosenberg, M.; Petrasso, R.; Glebov, V.; Stoeckl, C.

    2010-01-01

    Rugby-shaped hohlraums have been suggested as a way to enhance x-ray drive in the indirect drive approach to inertial confinement fusion. This Letter presents an experimental comparison of rugby-shaped and cylinder hohlraums used for D2 and DHe3-filled capsules implosions on the Omega laser facility, demonstrating an increase of x-ray flux by 18% in rugby-shaped hohlraums. The highest yields to date for deuterium gas implosions in indirect drive on Omega (1.5×1010 neutrons) were obtained, allowing for the first time the measurement of a DD burn history. Proton spectra measurements provide additional validation of the higher drive in rugby-shaped hohlraums.

  10. Quantitative Characterization of Phosphor Detector for Fusion Plasmas; Caracterizacion Cuantitativa de Detectores Luminiscentes para Plasmas de Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Baciero, A.; Zurro, B.; McCarthy, K. J.

    2004-07-01

    Experiments made to characterize phosphor screens with application as broadband radiation detectors, are described. Several radiation sources, covering the spectral range between the ultraviolet and X ray, were used. In addition, details are given of three original phosphor-screen-based detectors that were designed for use as broadband detectors in magnetically confined fusion devices. The first measurements obtained with these detectors in plasmas created in the TJ-II stellarator device are presented together with the analysis performed. (Author)

  11. Internet and web projects for fusion plasma science and education. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Eastman, Timothy E. [Senior Research Associate, Silver Spring, MD (United States)

    1999-08-30

    The plasma web site at http://www.plasmas.org provides comprehensive coverage of all plasma science and technology with site links worldwide. Prepared to serve the general public, students, educators, researchers, and decision-makers, the site covers basic plasma physics, fusion energy, magnetic confinement fusion, high energy density physics include ICF, space physics and astrophysics, pulsed-power, lighting, waste treatment, plasma technology, plasma theory, simulations and modeling.

  12. Ion irradiated graphite exposed to fusion-relevant deuterium plasma

    Energy Technology Data Exchange (ETDEWEB)

    Deslandes, Alec, E-mail: acd@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Guenette, Mathew C. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Corr, Cormac S. [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Karatchevtseva, Inna [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Thomsen, Lars [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia); Ionescu, Mihail [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Lumpkin, Gregory R.; Riley, Daniel P. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia)

    2014-12-01

    Graphite samples were irradiated with 5 MeV carbon ions to simulate the damage caused by collision cascades from neutron irradiation in a fusion environment. The ion irradiated graphite samples were then exposed to a deuterium plasma in the linear plasma device, MAGPIE, for a total ion fluence of ∼1 × 10{sup 24} ions m{sup −2}. Raman and near edge X-ray absorption fine structure (NEXAFS) spectroscopy were used to characterize modifications to the graphitic structure. Ion irradiation was observed to decrease the graphitic content and induce disorder in the graphite. Subsequent plasma exposure decreased the graphitic content further. Structural and surface chemistry changes were observed to be greatest for the sample irradiated with the greatest fluence of MeV ions. D retention was measured using elastic recoil detection analysis and showed that ion irradiation increased the amount of retained deuterium in graphite by a factor of four.

  13. Dust remobilization in fusion plasmas under steady state conditions

    Science.gov (United States)

    Tolias, P.; Ratynskaia, S.; De Angeli, M.; De Temmerman, G.; Ripamonti, D.; Riva, G.; Bykov, I.; Shalpegin, A.; Vignitchouk, L.; Brochard, F.; Bystrov, K.; Bardin, S.; Litnovsky, A.

    2016-02-01

    The first combined experimental and theoretical studies of dust remobilization by plasma forces are reported. The main theoretical aspects of remobilization in fusion devices under steady state conditions are analyzed. In particular, the dominant role of adhesive forces is highlighted and generic remobilization conditions—direct lift-up, sliding, rolling—are formulated. A novel experimental technique is proposed, based on controlled adhesion of dust grains on tungsten samples combined with detailed mapping of the dust deposition profile prior and post plasma exposure. Proof-of-principle experiments in the TEXTOR tokamak and the EXTRAP-T2R reversed-field pinch are presented. The versatile environment of the linear device Pilot-PSI allowed for experiments with different magnetic field topologies and varying plasma conditions that were complemented with camera observations.

  14. High Temperature Plasmas Theory and Mathematical Tools for Laser and Fusion Plasmas

    CERN Document Server

    Spatschek, Karl-Heinz

    2012-01-01

    Filling the gap for a treatment of the subject as an advanced course in theoretical physics with a huge potential for future applications, this monograph discusses aspects of these applications and provides theoretical methods and tools for their investigation. Throughout this coherent and up-to-date work the main emphasis is on classical plasmas at high-temperatures, drawing on the experienced author's specialist background. As such, it covers the key areas of magnetic fusion plasma, laser-plasma-interaction and astrophysical plasmas, while also including nonlinear waves and phenomena.

  15. High temperature superconductors for fusion at the Swiss Plasma Center

    Science.gov (United States)

    Bruzzone, P.; Wesche, R.; Uglietti, D.; Bykovsky, N.

    2017-08-01

    High temperature superconductors (HTS) may become in future an option for the superconducting magnets of commercial fusion plants. At the Swiss Plasma Center (SPC) the R&D activity toward HTS high current, high field cables suitable for fusion magnets started in 2012 and led in 2015 to the assembly of the first 60 kA, 12 T prototype conductor. The cable concept developed at the SPC is based on the principle of ‘soldered, twisted stacks’ of REBCO tapes. The required number of stacks is assembled in a cored flat cable, cooled by forced flow of supercritical helium. The sample environment of the test facility at SPC has been upgraded with a HTS adapter and a counter-flow heat exchanger to allow testing the HTS sample in a broader range of temperature (4.5 K-50 K) using the existing, NbTi based superconducting transformer and the closed loop refrigerator.

  16. Rugby-like hohlraum experimental designs for demonstrating x-ray drive enhancement

    Science.gov (United States)

    Amendt, Peter; Cerjan, C.; Hinkel, D. E.; Milovich, J. L.; Park, H.-S.; Robey, H. F.

    2008-01-01

    A suite of experimental designs for the Omega laser facility [Boehly et al., Opt. Commun. 133, 495 (1997)] using rugby and cylindrical hohlraums is proposed to confirm the energetics benefits of rugby-shaped hohlraums over cylinders under optimal implosion symmetry conditions. Postprocessed Dante x-ray drive measurements predict a 12-17eV (23%-36%) peak hohlraum temperature (x-ray flux) enhancement for a 1ns flattop laser drive history. Simulated core self-emission x-ray histories also show earlier implosion times by 200-400ps, depending on the hohlraum case-to-capsule ratio and laser-entrance-hole size. Capsules filled with 10 or 50atm of deuterium (DD) are predicted to give in excess of 1010 neutrons in two-dimensional hohlraum simulations in the absence of mix, enabling DD burn history measurements for the first time in indirect-drive on Omega. Capsule designs with 50atm of DHe3 are also proposed to make use of proton slowing for independently verifying the drive benefits of rugby hohlraums. Scale-5/4 hohlraum designs are also introduced to provide further margin to potential laser-plasma-induced backscatter and hot-electron production.

  17. Soft X-ray measurements in magnetic fusion plasma physics

    Science.gov (United States)

    Botrugno, A.; Gabellieri, L.; Mazon, D.; Pacella, D.; Romano, A.

    2010-11-01

    Soft X-ray diagnostic systems and their successful application in the field of magnetic fusion plasma physics are discussed. Radiation with wavelength in the region of Soft X-Ray (1-30 keV) is largely produced by high temperature plasmas, carrying important information on many processes during a plasma discharge. Soft X-ray diagnostics are largely used in various fusion devices all over the world. These diagnostic systems are able to obtain information on electron temperature, electron density, impurity transport, Magneto Hydro Dynamic instabilities. We will discuss the SXR diagnostic installed on FTU in Frascati (Italy) and on Tore Supra in Cadarache (France), with special emphasis on diagnostic performances. Moreover, we will discuss the two different inversion methods for tomographic reconstruction used in Frascati and in Cadarache, the first one is relied on a guessed topology of iso-emissivity surfaces, the second one on regularization techniques, like minimum Fisher or maximum entropy. Finally, a new and very fast 2D imaging system with energy discrimination and high time resolution will be summarized as an alternative approach of SXR detection system.

  18. BOOK REVIEW: Fundamentals of Plasma Physics and Controlled Fusion

    Science.gov (United States)

    Brambilla, Marco

    1998-04-01

    Professor Kenro Miyamoto, already well known for his textbook Plasma Physics for Nuclear Fusion (MIT Press, Cambridge, MA, 1976; revised edition 1989), has now published a new book entitled Fundamentals of Plasma Physics and Controlled Fusion (Iwanami Book Service Center, Tokyo, 1997). To a large extent, the new book is a somewhat shortened and well reorganized version of its predecessor. The style, concise and matter of fact, clearly shows the origin of the text in lectures given by the author to graduate students. As announced by the title, the book is divided into two parts: the first part (about 250 pages) is a general introduction to the physics of plasmas, while the second, somewhat shorter, part (about 150 pages), is devoted to a description of the most important experimental approaches to achieving controlled thermonuclear fusion. Even in the first part, moreover, the choice of subjects is consistently oriented towards the needs of fusion research. Thus, the introduction to the behaviour of charged particles (particle motion, collisions, etc.) and to the collective description of plasmas is quite short, although the reader will get a flavour of all the most important topics and will find a number of examples chosen for their relevance to fusion applications (only the presentation of the Vlasov equation, in the second section of Chapter 4, might be criticized as so concise as to be almost misleading, since the difference between microscopic and macroscopic fields is not even mentioned). Considerably more space is devoted to the magnetohydrodynamic (MHD) description of equilibrium and stability. This part includes the solution of the Grad-Shafranov equation for circular tokamaks, a brief discussion of Pfirsch-Schlüter, neoclassical and anomalous diffusion, and two relatively long chapters on the most important ideal and resistive MHD instabilities of toroidal plasmas; drift and ion temperature gradient driven instabilities are also briefly presented. The

  19. Scaling mechanisms of vapour/plasma shielding from laser-produced plasmas to magnetic fusion regimes

    Science.gov (United States)

    Sizyuk, Tatyana; Hassanein, Ahmed

    2014-02-01

    The plasma shielding effect is a well-known mechanism in laser-produced plasmas (LPPs) reducing laser photon transmission to the target and, as a result, significantly reducing target heating and erosion. The shielding effect is less pronounced at low laser intensities, when low evaporation rate together with vapour/plasma expansion processes prevent establishment of a dense plasma layer above the surface. Plasma shielding also loses its effectiveness at high laser intensities when the formed hot dense plasma plume causes extensive target erosion due to radiation fluxes back to the surface. The magnitude of emitted radiation fluxes from such a plasma is similar to or slightly higher than the laser photon flux in the low shielding regime. Thus, shielding efficiency in LPPs has a peak that depends on the laser beam parameters and the target material. A similar tendency is also expected in other plasma-operating devices such as tokamaks of magnetic fusion energy (MFE) reactors during transient plasma operation and disruptions on chamber walls when deposition of the high-energy transient plasma can cause severe erosion and damage to the plasma-facing and nearby components. A detailed analysis of these abnormal events and their consequences in future power reactors is limited in current tokamak reactors. Predictions for high-power future tokamaks are possible only through comprehensive, time-consuming and rigorous modelling. We developed scaling mechanisms, based on modelling of LPP devices with their typical temporal and spatial scales, to simulate tokamak abnormal operating regimes to study wall erosion, plasma shielding and radiation under MFE reactor conditions. We found an analogy in regimes and results of carbon and tungsten erosion of the divertor surface in ITER-like reactors with erosion due to laser irradiation. Such an approach will allow utilizing validated modelling combined with well-designed and well-diagnosed LPP experimental studies for predicting

  20. Simulation of transition dynamics to high confinement in fusion plasmas

    CERN Document Server

    Nielsen, A H; Madsen, J; Naulin, V; Rasmussen, J Juul; Wan, B N

    2014-01-01

    The transition dynamics from the low (L) to the high (H) confinement mode in magnetically confined plasmas is investigated using a first-principles four-field fluid model. Numerical results are in close agreement with measurements from the Experimental Advanced Superconducting Tokamak - EAST. Particularly, the slow transition with an intermediate dithering phase is well reproduced by the numerical solutions. Additionally, the model reproduces the experimentally determined L-H transition power threshold scaling that the ion power threshold increases with increasing particle density. The results hold promise for developing predictive models of the transition, essential for understanding and optimizing future fusion power reactors.

  1. A Vlasov equation with Dirac potential used in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Bardos, Claude [Universite Paris-Diderot, Laboratoire J.-L. Lions, BP187, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Nouri, Anne [Laboratoire d' Analyse, Topologie et Probabilites (UMR 6632), Aix-Marseille Universite, 39 Rue Joliot-Curie, 13453 Marseille Cedex 13 (France)

    2012-11-15

    Well-posedness of the Cauchy problem is analyzed for a singular Vlasov equation governing the evolution of the ionic distribution function of a quasineutral fusion plasma. The Penrose criterium is adapted to the linearized problem around a time and space homogeneous distribution function showing (due to the singularity) more drastic differences between stable and unstable situations. This pathology appears on the full nonlinear problem, well-posed locally in time with analytic initial data, but generally ill-posed in the Hadamard sense. Eventually with a very different class of solutions, mono-kinetic, which constrains the structure of the density distribution, the problem becomes locally in time well-posed.

  2. Spectrum analysis of hydrogen plasma in spherically convergent beam fusion

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, Kazuki; Yamauchi, Kunihito; Watanabe, Masato; Sunaga, Yoshitaka; Hotta, Eiki [Tokyo Institute of Technology, Dept. of Energy Sciences, Yokohama, Kanagawa (Japan); Okino, Akitoshi [Tokyo Institute of Technology, Dept. of Electrical and Electronic Engineering, Tokyo (Japan)

    2001-09-01

    Spectroscopic analysis of spherical glow discharge fusion device was carried out using hydrogen gas. Effects of the discharge current and cathode voltage on spectrum profiles of hydrogen Balmar lines were measured. The profiles of all hydrogen lines were broadened with the cathode voltage. From the relationship between the maximum broadening width and the cathode voltage, it was indicated that the broadening was caused by the Doppler effect. From the spatial distribution of emission intensity, it was found that plasma core size became larger with discharge current and smaller with cathode voltage. (author)

  3. Educational Outreach at the MIT Plasma Science and Fusion Center

    Science.gov (United States)

    Rivenberg, Paul; Thomas, Paul

    2006-10-01

    At the MIT PSFC, student and staff volunteers work together to increase the public's knowledge of fusion science and plasma technology. Seeking to generate excitement in young people about science and engineering, the PSFC hosts a number of educational outreach activities throughout the year, including Middle and High School Outreach Days. The PSFC also has an in-school science demonstration program on the theme of magnetism. The Mr. Magnet Program, headed by Mr. Paul Thomas, has been bringing lively demonstrations on magnetism into local elementary and middle schools for 15 years. This year Mr. Magnet presented the program to nearly 30,000 students at over 67 schools and other events, reaching kindergartners through college freshmen. In addition to his program on magnetism, he is offering an interactive lecture about plasma to high schools. The "Traveling Plasma Lab" encourages students to learn more about plasma science while having fun investigating plasma properties using actual laboratory techniques and equipment. Beyond the classroom, Paul Thomas has provided technical training for Boston Museum of Science staff in preparation for the opening of a Star Wars exhibit. His hands-on demos have also been filmed by the History Channel for a one-hour program about Magnetism, which aired in June 2006.

  4. Optimization of laser hole drilling process on thick gold spherical hohlraums for intense X-ray generation

    Indian Academy of Sciences (India)

    S R Patwa; S Jain; P K Tripathi; A S Joshi; P D Gupta

    2010-12-01

    Hohlraums of high- materials are used as soft X-ray sources to study indirect drive fusion, equation of state of materials etc. Here, we describe a method to develop spherical gold hohlraums of large wall thickness (∼ 70–80 m) on which laser entrance and diagnostics holes are drilled using a 10 Hz Nd:YLF laser. Holes of different diameters have been drilled with lenses of different focal lengths. The back wall of the hohlraum is protected from the damage by shutting off the laser at pre-determined hole drilling time.

  5. Microwave Receivers for Fast-Ion Detection in Fusion Plasmas

    DEFF Research Database (Denmark)

    Furtula, Vedran

    collective Thomson scattering (CTS). The Danish CTS group has been involved in fusion plasma experiments for more than 10 years and the future plans will most probably include the International Thermonuclear Experimental Reactor (ITER). Current CTS systems designed by the Danish group are specified...... are assessed. For the ITER HFS receiver we have designed and measured the quasioptical components that form a transmission link between the plasma and the radio frequency (RF) electronics. This HFS receiver is required to resolve the near parallel velocity components created by the alpha particles. Secondly...... have measured and analyzed all the receiver components starting from the two notch filters to the fifty square-law detector diodes. The receiver sensitivity is calculated from the system measurements and compared with the expected sensitivity based on the individual component measurements. Besides...

  6. Particle model for nonlocal heat transport in fusion plasmas.

    Science.gov (United States)

    Bufferand, H; Ciraolo, G; Ghendrih, Ph; Lepri, S; Livi, R

    2013-02-01

    We present a simple stochastic, one-dimensional model for heat transfer in weakly collisional media as fusion plasmas. Energies of plasma particles are treated as lattice random variables interacting with a rate inversely proportional to their energy schematizing a screened Coulomb interaction. We consider both the equilibrium (microcanonical) and nonequilibrium case in which the system is in contact with heat baths at different temperatures. The model exhibits a characteristic length of thermalization that can be associated with an interaction mean free path and one observes a transition from ballistic to diffusive regime depending on the average energy of the system. A mean-field expression for heat flux is deduced from system heat transport properties. Finally, it is shown that the nonequilibrium steady state is characterized by long-range correlations.

  7. Characterizing high energy spectra of NIF ignition Hohlraums using a differentially filtered high energy multipinhole x-ray imager.

    Science.gov (United States)

    Park, Hye-Sook; Dewald, E D; Glenzer, S; Kalantar, D H; Kilkenny, J D; MacGowan, B J; Maddox, B R; Milovich, J L; Prasad, R R; Remington, B A; Robey, H F; Thomas, C A

    2010-10-01

    Understanding hot electron distributions generated inside Hohlraums is important to the national ignition campaign for controlling implosion symmetry and sources of preheat. While direct imaging of hot electrons is difficult, their spatial distribution and spectrum can be deduced by detecting high energy x-rays generated as they interact with target materials. We used an array of 18 pinholes with four independent filter combinations to image entire Hohlraums with a magnification of 0.87× during the Hohlraum energetics campaign on NIF. Comparing our results with Hohlraum simulations indicates that the characteristic 10-40 keV hot electrons are mainly generated from backscattered laser-plasma interactions rather than from Hohlraum hydrodynamics.

  8. Plasma engineering studies for Tennessee Tokamak (TENTOK) fusion power reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, K.E.; Lacatski, J.T.; Miller, J.B.; Bryan, W.E.; King, P.W.; Santoro, R.T.; Uckan, N.A.; Shannon, T.E.

    1984-02-01

    This paper summarizes the results of the plasma engineering and systems analysis studies for the Tennessee Tokamak (TENTOK) fusion power reactor. TENTOK is a 3000-MW(t) central station power plant that uses deuterium-tritium fuel in a D-shaped tokamak plasma configuration with a double-null poloidal divertor. The major parameters are R/sub 0/ = 6.4 m, a = 1.6 m, sigma (elongation) = 1.65, (n) = 1.5 x 10/sup 20/ m/sup -3/, (T) = 15 keV, (..beta..) = 6%, B/sub T/ (on-axis) = 5.6 T, I/sub p/ = 8.5 MA, and wall loading = 3 MW/m/sup 2/. Detailed analyses are performed in the areas of (1) transport simulation using the one-and-one-half-dimensional (1-1/2-D) WHIST transport code, (2) equilibrium/poloidal field coil systems, (3) neutral beam and radiofrequency (rf) heating, and (4) pellet fueling. In addition, impurity control systems, diagnostics and controls, and possible microwave plasma preheating and steady-state current drive options are also considered. Some of the major features of TENTOK include rf heating in the ion cyclotron range of frequencies, superconducting equilibrium field coils outside the superconducting toroidal field coils, a double-null poloidal divertor for impurity control and alpha ash removal, and rf-assisted plasma preheating and current startup.

  9. Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology

    Science.gov (United States)

    Rawat, R. S.

    2015-03-01

    The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 1010 J/m3. The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of

  10. Comparison of high-density carbon implosions in unlined uranium versus gold hohlraums

    Science.gov (United States)

    Dewald, Eduard; Meezan, Nathan; Tommasini, Riccardo; Khan, Shahab; MacKinnon, Andrew; Berzak Hopkins, Laura; Divol, Laurent; Lepape, Sebastien; Moore, Alastair; Schneider, Marilyn; Pak, Arthur; Nikroo, Abbas; Landen, Otto

    2016-10-01

    In Inertial Confinement Fusion (ICF) implosions, laser energy is converted to x-ray radiation in hohlraums with High-Z walls. At radiation temperatures near 300 eV relevant for ICF experiments, the radiative losses in heating the wall are lower for U than for Au hohlraums. Furthermore, the intensity of the ``M-band'' x-rays with photon energies h ν >1.8 keV is lower for uranium, allowing for reduced capsule dopant concentrations employed to minimize inner ablator preheat and hence keep favorable fuel/ablator interface Atwood numbers. This in turn improves the ablator rocket efficiency and reduces the risk of polluting the hot-spot with emissive dopant material. The first uranium vacuum hohlraum experiments on the National Ignition Facility (NIF) with undoped high-density carbon (HDC, or diamond) capsules have demonstrated 30% lower ``M-band'' intensity relative to Au, resulting in lower inflight ablator thickness due to reduced preheat. In addition, fusion neutron yields are 2x higher in U than in Au hohlraums for D2-gas filled capsule implosions at ICF relevant velocities of 380 +/-20 km/s. These results have led the NIF ICF implosions to routinely employ U hohlraums. Prepared by LLNL under Contract DE-AC52-07NA27344.

  11. Gas-filled Rugby hohlraum energetics and implosions experiments on OMEGA

    Science.gov (United States)

    Casner, Alexis; Philippe, F.; Tassin, V.; Seytor, P.; Monteil, M. C.; Villette, B.; Reverdin, C.

    2010-11-01

    Recent experiments [1,2] have validated the x-ray drive enhancement provided by rugby-shaped hohlraums over cylinders in the indirect drive (ID) approach to inertial confinement fusion (ICF). This class of hohlraum is the baseline design for the Laser Mégajoule program, is also applicable to the National Ignition Facility and could therefore benefit ID Inertial Fusion Energy studies. We have carried out a serie of energetics and implosions experiments with OMEGA ``scale 1'' rugby hohlraums [1,2]. For empty hohlraums these experiments provide complementary measurements of backscattered light along 42 cone, as well as detailed drive history. In the case of gas-filled rugby hohlraums we have also study implosion performance (symmetry, yield, bangtime, hotspot spectra...) using a high contrast shaped pulse leading to a different implosion regime and for a range of capsule convergence ratios. These results will be compared with FCI2 hydrocodes calculations and future experimental campaigns will be suggested. [4pt] [1] F. Philippe et al., Phys. Rev. Lett. 104, 035004 (2010). [0pt] [2] H. Robey et al., Phys. Plasnas 17, 056313 (2010).

  12. Plasma-Facing Materials Research For Fusion Reactors At FOM Rijnhuizen

    NARCIS (Netherlands)

    Rapp, J.; De Temmerman, G.; van Rooij, G. J.; van Emmichoven, P. A. Zeijlma; Kleyn, A. W.

    2011-01-01

    In next generation magnetic fusion devices such as ITER, plasma-facing materials are exposed to unprecedented high ion, power and neutron fluxes. Those extreme conditions cannot be recreated in current fusion devices from the tokamak type. The plasma-surface interaction is still an area of great unc

  13. Plasma-facing materials research for fusion reactors at Fom Rijnhuizen

    NARCIS (Netherlands)

    Rapp, J.; De Temmerman, G.; van Rooij, G.J.; Zeijlmans van Emmichoven, P.A.; Kleijn, A.W.

    2011-01-01

    In next generation magnetic fusion devices such as ITER, plasma-facing materials are exposed to unprecedented high ion, power and neutron fluxes. Those extreme conditions cannot be recreated in current fusion devices from the tokamak type. The plasma-surface interaction is still an area of great unc

  14. Plasma-Facing Materials Research For Fusion Reactors At FOM Rijnhuizen

    NARCIS (Netherlands)

    Rapp, J.; De Temmerman, G.; van Rooij, G. J.; van Emmichoven, P. A. Zeijlma; Kleyn, A. W.

    2011-01-01

    In next generation magnetic fusion devices such as ITER, plasma-facing materials are exposed to unprecedented high ion, power and neutron fluxes. Those extreme conditions cannot be recreated in current fusion devices from the tokamak type. The plasma-surface interaction is still an area of great unc

  15. Plasma-facing materials research for fusion reactors at Fom Rijnhuizen

    NARCIS (Netherlands)

    Rapp, J.; De Temmerman, G.; van Rooij, G.J.; Zeijlmans van Emmichoven, P.A.; Kleijn, A.W.

    2011-01-01

    In next generation magnetic fusion devices such as ITER, plasma-facing materials are exposed to unprecedented high ion, power and neutron fluxes. Those extreme conditions cannot be recreated in current fusion devices from the tokamak type. The plasma-surface interaction is still an area of great unc

  16. Real-time wavelet detection of crashes in limit cycles of non-stationary fusion plasmas

    NARCIS (Netherlands)

    van Berkel, M.; Witvoet, G.; M.R. de Baar,; Nuij, Pwjm; Morschec, H. G. ter; Steinbuch, M.

    2011-01-01

    The high performance mode (H-mode) is one of the baseline plasma scenarios for the experimental fusion reactor ITER. This scenario features a periodic crash-like reorganization of the plasma pressure and the magnetic flux in the plasma core and plasma periphery. The core instability is often referre

  17. 1991 US-Japan workshop on Nuclear Fusion in Dense Plasmas. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ichimaru, S. [ed.] [Tokyo Univ. (Japan). Dept. of Physics; Tajima, T. [ed.] [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies

    1991-10-01

    The scientific areas covered at the Workshop may be classified into the following subfields: (1) basic theory of dense plasma physics and its interface with atomic physics and nuclear physics; (2) physics of dense z-pinches, ICF plasmas etc; (3) stellar interior plasmas; (4) cold fusion; and (5) other dense plasmas.

  18. 1991 US-Japan workshop on Nuclear Fusion in Dense Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ichimaru, S. (ed.) (Tokyo Univ. (Japan). Dept. of Physics); Tajima, T. (ed.) (Texas Univ., Austin, TX (United States). Inst. for Fusion Studies)

    1991-10-01

    The scientific areas covered at the Workshop may be classified into the following subfields: (1) basic theory of dense plasma physics and its interface with atomic physics and nuclear physics; (2) physics of dense z-pinches, ICF plasmas etc; (3) stellar interior plasmas; (4) cold fusion; and (5) other dense plasmas.

  19. Secondary Nuclear Reactions in Magneto-Inertial Fusion Plasmas

    Science.gov (United States)

    Knapp, Patrick

    2014-10-01

    The goal of Magneto-Inertial Fusion (MIF) is to relax the extreme pressure requirements of inertial confinement fusion by magnetizing the fuel. Understanding the level of magnetization at stagnation is critical for charting the performance of any MIF concept. We show here that the secondary nuclear reactions in magnetized deuterium plasma can be used to infer the magnetic field-radius product (BR), the critical confinement parameter for MIF. The secondary neutron yields and spectra are examined and shown to be extremely sensitive to BR. In particular, embedded magnetic fields are shown to affect profoundly the isotropy of the secondary neutron spectra. Detailed modeling of these spectra along with the ratio of overall secondary to primary neutron yields is used to form the basis of a diagnostic technique used to infer BR at stagnation. Effects of gradients in density, temperature and magnetic field strength are examined, as well as other possible non-uniform fuel configurations. Computational results employing a fully kinetic treatment of charged reaction product transport and Monte Carlo treatment of secondary reactions are compared to results from recent experiments at Sandia National Laboratories' Z machine testing the MAGnetized Liner Inertial Fusion (MagLIF) concept. The technique reveals that the charged reaction products were highly magnetized in these experiments. Implications for eventual ignition-relevant experiments with deuterium-tritium fuel are discussed. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  20. Stabilization effect of Weibel modes in relativistic laser fusion plasma

    Science.gov (United States)

    Belghit, Slimen; Sid, Abdelaziz

    2016-06-01

    In this work, the Weibel instability (WI) due to inverse bremsstrahlung (IB) absorption in a laser fusion plasma has been investigated. The stabilization effect due to the coupling of the self-generated magnetic field by WI with the laser wave field is explicitly shown. In this study, the relativistic effects are taken into account. Here, the basic equation is the relativistic Fokker-Planck (F-P) equation. The main obtained result is that the coupling of self-generated magnetic field with the laser wave causes a stabilizing effect of excited Weibel modes. We found a decrease in the spectral range of Weibel unstable modes. This decreasing is accompanied by a reduction of two orders in the growth rate of instable Weibel modes or even stabilization of these modes. It has been shown that the previous analysis of the Weibel instability due to IB has overestimated the values of the generated magnetic fields. Therefore, the generation of magnetic fields by the WI due to IB should not affect the experiences of an inertial confinement fusion.

  1. Inhibition of HIV-1 endocytosis allows lipid mixing at the plasma membrane, but not complete fusion

    Directory of Open Access Journals (Sweden)

    de la Vega Michelle

    2011-12-01

    Full Text Available Abstract Background We recently provided evidence that HIV-1 enters HeLa-derived TZM-bl and lymphoid CEMss cells by fusing with endosomes, whereas its fusion with the plasma membrane does not proceed beyond the lipid mixing step. The mechanism of restriction of HIV-1 fusion at the cell surface and/or the factors that aid the virus entry from endosomes remain unclear. Results We examined HIV-1 fusion with a panel of target cells lines and with primary CD4+ T cells. Kinetic measurements of fusion combined with time-resolved imaging of single viruses further reinforced the notion that HIV-1 enters the cells via endocytosis and fusion with endosomes. Furthermore, we attempted to deliberately redirect virus fusion to the plasma membrane, using two experimental strategies. First, the fusion reaction was synchronized by pre-incubating the viruses with cells at reduced temperature to allow CD4 and coreceptors engagement, but not the virus uptake or fusion. Subsequent shift to a physiological temperature triggered accelerated virus uptake followed by entry from endosomes, but did not permit fusion at the cell surface. Second, blocking HIV-1 endocytosis by a small-molecule dynamin inhibitor, dynasore, resulted in transfer of viral lipids to the plasma membrane without any detectable release of the viral content into the cytosol. We also found that a higher concentration of dynasore is required to block the HIV-endosome fusion compared to virus internalization. Conclusions Our results further support the notion that HIV-1 enters disparate cell types through fusion with endosomes. The block of HIV-1 fusion with the plasma membrane at a post-lipid mixing stage shows that this membrane is not conducive to fusion pore formation and/or enlargement. The ability of dynasore to interfere with the virus-endosome fusion suggests that dynamin could be involved in two distinct steps of HIV-1 entry - endocytosis and fusion within intracellular compartments.

  2. Lowering the risk of stimulated Brillouin backscatter from NIF hohlraums by re-pointing beams

    Science.gov (United States)

    Berger, Richard; Baker, K. L.; Thomas, C. A.; Milovich, J. L.; Langdon, A. B.; Strozzi, D. J.; Michel, M.

    2015-11-01

    The 64 beams that make a 50 degree angle with the hohlraum axis have been measured to reflect by Stimulated Brillouin Backscatter (SBS) enough laser light to cause optical damage and limit design parameter space. The amount of backscatter has been seen to depend on the initial plasma density filling the hohlraum, the hohlraum wall material, and the laser pulse length. The most important parameter causing SBS is the laser intensity on the hohlraum wall. In previous hohlraum designs, the intensity of the 50 degree beams has been controlled by cross-beam energy transfer (CBET). [P. Michel et al., Phys. Rev. Lett. 102, 025004 (2009)] Recent designs with reduced CBET have experienced an increase in SBS. Here we show that repointing beams can reduce the laser intensity at the wall and still maintain good beam smoothing. The reduction in intensity is achieved by separating the 44 and 50 degree cones of beams along the hohlraum axis and then repointing beams within each cone to reduce overlap while preserving polarization smoothing. PF3D simulations show dramatic reductions of SBS are possible. Experiments will determine whether increased laser entrance hole sizes will be required and whether this technique will open up new design options. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  3. Plasma facing materials and components for future fusion devices—development, characterization and performance under fusion specific loading conditions

    Science.gov (United States)

    Linke, J.

    2006-04-01

    The plasma exposed components in existing and future fusion devices are strongly affected by the plasma material interaction processes. These mechanisms have a strong influence on the plasma performance; in addition they have major impact on the lifetime of the plasma facing armour and the joining interface between the plasma facing material (PFM) and the heat sink. Besides physical and chemical sputtering processes, high heat quasi-stationary fluxes during normal and intense thermal transients are of serious concern for the engineers who develop reliable wall components. In addition, the material and component degradation due to intense fluxes of energetic neutrons is another critical issue in D-T-burning fusion devices which requires extensive R&D. This paper presents an overview on the materials development and joining, the testing of PFMs and components, and the analysis of the neutron irradiation induced degradation.

  4. 激光黑腔靶等离子体相互作用研究现状和发展趋势%Present Status and Development Trends in Interaction Study on Laser HohlraumTarget and Plasmas

    Institute of Scientific and Technical Information of China (English)

    张家泰

    2001-01-01

    综述近年来围绕美国的“国家点火装置”(NIF)所开展的大尺度激光腔靶等离子体相互作用研究,结合国内的研究,对抑制受激布里渊散射(SBS)减少散射光、抑制受激拉曼散射(SRS)减少超热电子、成丝(FI)以及激光均匀辐照方法进行了深入的分析和综述。评述了研究现状和取得的成果,还分析了该领域的发展趋势,提出了我国惯性约束聚变(ICF)等离子体研究应该注意的一些问题和建议。%Study on interaction of large size laser hohlraum target and plasmas performed around NIF is reviewed, and analyses in-depth and comprehensive description were made on the suppression of stimulated Brillouin scattering (SBS) to reduce the scattering light,suppression of stimulated Raman scattering (SRS) to reduce the super thermal electrons,filamentation and the methods to get uniform laser irradiation incorporating with our own research results.The research status and the results achieved were reviewed,the development trend in this field was analyzed,and some problems and suggestions to which attention should be paid in the ICF plasma research in our country were put forward.

  5. Scattering of radio frequency waves by turbulence in fusion plasmas

    Science.gov (United States)

    Ram, Abhay K.

    2016-10-01

    In tokamak fusion plasmas, coherent fluctuations in the form of blobs or filaments and incoherent fluctuations due to turbulence are routinely observed in the scrape-off layer. Radio frequency (RF) electromagnetic waves, excited by antenna structures placed near the wall of a tokamak, have to propagate through the scrape-off layer before reaching the core of the plasma. While the effect of fluctuations on RF waves has not been quantified experimentally, there are telltale signs, arising from differences between results from simulations and from experiments, that fluctuations can modify the spectrum of RF waves. Any effect on RF waves in the scrape-off layer can have important experimental consequences. For example, electron cyclotron waves are expected to stabilize the deleterious neoclassical tearing mode (NTM) in ITER. Spectral and polarization changes due to scattering will modify the spatial location and profile of the current driven by the RF waves, thereby affecting the control of NTMs. Pioneering theoretical studies and complementary computer simulations have been pursued to elucidate the impact of fluctuations on RF waves. From the full complement of Maxwell's equations for cold, magnetized plasmas, it is shown that the Poynting flux in the wake of filaments develops spatial structure due to diffraction and shadowing. The uniformity of power flow into the plasma is affected by side-scattering, modifications to the wave spectrum, and coupling to plasma waves other than the incident RF wave. The Snell's law and the Fresnel equations have been reformulated within the context of magnetized plasmas. They are distinctly different from their counterparts in scalar dielectric media, and reveal new and important physical insight into the scattering of RF waves. The Snell's law and Fresnel equations are the basis for the Kirchhoff approximation necessary to determine properties of the scattered waves. Furthermore, this theory is also relevant for studying back

  6. Microwave receivers for fast-ion detection in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Furtula, V.

    2012-02-15

    The main objectives of this thesis are to determine fundamental properties of a millimeter wave radiometer used to detect radiation associated with dynamics of fast ions and to investigate possibilities for improvements and new designs. The detection of fast ions is based on a principle called collective Thomson scattering (CTS). The Danish CTS group has been involved in fusion plasma experiments for more than 10 years and the future plans will most probably include the International Thermonuclear Experimental Reactor (ITER). Current CTS systems designed by the Danish group are specified for the frequency range from 100 to 110 GHz. In this thesis we follow the path of the radiation from a fusion plasma to the data acquisition unit. Firstly, the scattered radiation passes through the quasi-optical system. Quasi-optical elements required to be installed on the high field side (HFS) on the ITER are assessed. For the ITER HFS receiver we have designed and measured the quasi-optical components that form a transmission link between the plasma and the radio frequency (RF) electronics. This HFS receiver is required to resolve the near parallel velocity components created by the alpha particles. Secondly, the radiation will encounter the RF part. This part is not yet designed for ITER, but instead the solution is addressed to the CTS receiver installed at ASDEX Upgrade (AUG).We have put effort to thoroughly examine and evaluate the performance of the receiver components and the receiver as an assembled unit. We have measured and analyzed all the receiver components starting from the two notch filters to the fifty square-law detector diodes. The receiver sensitivity is calculated from the system measurements and compared with the expected sensitivity based on the individual component measurements. Besides the system considerations we have also studied improvements of two critical components of the receiver. The first component is the notch filter, which is needed to block

  7. Modeling of transient dust events in fusion edge plasmas with DUSTT-UEDGE code

    Science.gov (United States)

    Smirnov, R. D.; Krasheninnikov, S. I.; Pigarov, A. Yu.; Rognlien, T. D.

    2016-10-01

    It is well known that dust can be produced in fusion devices due to various processes involving structural damage of plasma exposed materials. Recent computational and experimental studies have demonstrated that dust production and associated with it plasma contamination can present serious challenges in achieving sustained fusion reaction in future fusion devices, such as ITER. To analyze the impact, which dust can have on performance of fusion plasmas, modeling of coupled dust and plasma transport with DUSTT-UEDGE code is used by the authors. In past, only steady-state computational studies, presuming continuous source of dust influx, were performed due to iterative nature of DUSTT-UEDGE code coupling. However, experimental observations demonstrate that intermittent injection of large quantities of dust, often associated with transient plasma events, may severely impact fusion plasma conditions and even lead to discharge termination. In this work we report on progress in coupling of DUSTT-UEDGE codes in time-dependent regime, which allows modeling of transient dust-plasma transport processes. The methodology and details of the time-dependent code coupling, as well as examples of simulations of transient dust-plasma transport phenomena will be presented. These include time-dependent modeling of impact of short out-bursts of different quantities of tungsten dust in ITER divertor on the edge plasma parameters. The plasma response to the out-bursts with various duration, location, and ejected dust sizes will be analyzed.

  8. A1.5 Fusion Performance

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, P

    2011-03-31

    Analysis and radiation hydrodynamics simulations for expected high-gain fusion target performance on a demonstration 1-GWe Laser Inertial Fusion Energy (LIFE) power plant in the mid-2030s timeframe are presented. The required laser energy driver is 2.2 MJ at a 0.351-{micro}m wavelength, and a fusion target gain greater than 60 at a repetition rate of 16 Hz is the design goal for economic and commercial attractiveness. A scaling-law analysis is developed to benchmark the design parameter space for hohlraum-driven central hot-spot ignition. A suite of integrated hohlraum simulations is presented to test the modeling assumptions and provide a basis for a near-term experimental resolution of the key physics uncertainties on the National Ignition Facility (NIF). The NIF is poised to demonstrate ignition by 2012 based on the central hot spot (CHS) mode of ignition and propagating thermonuclear burn [1]. This immediate prospect underscores the imperative and timeliness of advancing inertial fusion as a carbon-free, virtually limitless source of energy by the mid-21st century to substantially offset fossil fuel technologies. To this end, an intensive effort is underway to leverage success at the NIF and to provide the foundations for a prototype 'LIFE.1' engineering test facility by {approx}2025, followed by a commercially viable 'LIFE.2' demonstration power plant operating at 1 GWe by {approx}2035. The current design goal for LIFE.2 is to accommodate {approx}2.2 MJ of laser energy (entering the high-Z radiation enclosure or 'hohlraum') at a 0.351-{micro}m wavelength operating at a repetition rate of 16 Hz and to provide a fusion target yield of 132 MJ. To achieve this design goal first requires a '0-d' analytic gain model that allows convenient exploration of parameter space and target optimization. This step is then followed by 2- and 3-dimensional radiation-hydrodynamics simulations that incorporate laser beam transport, x

  9. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    Science.gov (United States)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

    2015-04-01

    A recent low gas-fill density (0.6 mg/cc 4He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  10. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2015-04-15

    A recent low gas-fill density (0.6 mg/cc {sup 4}He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc {sup 4}He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  11. Fusion plasma turbulence described by modified sandpile dynamics.

    Science.gov (United States)

    Ghendrih, Philippe; Ciraolo, Guido; Dif-Pradalier, Guilhem; Norscini, Claudia; Sarazin, Yanick; Abiteboul, Jérémie; Cartier-Michaud, Thomas; Garbet, Xavier; Grandgirard, Virginie; Strugarek, Antoine

    2014-04-01

    Transport in fusion plasmas is investigated with modified sandpile models. Based on results from more complete simulations, the sandpile model is modified in steps. Models with a constant source are obtained by coupling two sandpiles. Decoupling the mean field from the bursts allows one to develop a reduced model which captures some of the key features of flux-driven simulations. In the latter sandpile model, turbulent transport is mediated by the burst field while the mean-field gradient governs the transfer to the bursts. This allows one to investigate spreading, namely turbulent transport into stable regions, and transport barriers, regions where the transfer from the mean field to turbulence is reduced. Both cases are found to exhibit intermittent behaviors when the system undergoes spontaneous transitions between different transport regimes. Finally, one couples to the sandpile algorithm a species evolution algorithm that assigns a quality factor to each site. The latter appears to self-generate corrugations, or micro-barriers. These are found to naturally cluster radially in structures that are large enough to impact confinement. The mechanisms introduced to alleviate the clustering, destabilization of the corrugation by overloading and by secondary instabilities at critical radial extents, are shown to generate long-range relaxation events in space and in time with quasiperiodic reorganization of the corrugation pattern.

  12. Present status on atomic and molecular data relevant to fusion plasma diagnostics and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Tawara, H. [ed.

    1997-01-01

    This issue is the collection of the paper presented status on atomic and molecular data relevant to fusion plasma diagnostics and modeling. The 10 of the presented papers are indexed individually. (J.P.N.)

  13. A high-speed two-frame, 1-2 ns gated X-ray CMOS imager used as a hohlraum diagnostic on the National Ignition Facility (invited)

    Science.gov (United States)

    Chen, Hui; Palmer, N.; Dayton, M.; Carpenter, A.; Schneider, M. B.; Bell, P. M.; Bradley, D. K.; Claus, L. D.; Fang, L.; Hilsabeck, T.; Hohenberger, M.; Jones, O. S.; Kilkenny, J. D.; Kimmel, M. W.; Robertson, G.; Rochau, G.; Sanchez, M. O.; Stahoviak, J. W.; Trotter, D. C.; Porter, J. L.

    2016-11-01

    A novel x-ray imager, which takes time-resolved gated images along a single line-of-sight, has been successfully implemented at the National Ignition Facility (NIF). This Gated Laser Entrance Hole diagnostic, G-LEH, incorporates a high-speed multi-frame CMOS x-ray imager developed by Sandia National Laboratories to upgrade the existing Static X-ray Imager diagnostic at NIF. The new diagnostic is capable of capturing two laser-entrance-hole images per shot on its 1024 × 448 pixels photo-detector array, with integration times as short as 1.6 ns per frame. Since its implementation on NIF, the G-LEH diagnostic has successfully acquired images from various experimental campaigns, providing critical new information for understanding the hohlraum performance in inertial confinement fusion (ICF) experiments, such as the size of the laser entrance hole vs. time, the growth of the laser-heated gold plasma bubble, the change in brightness of inner beam spots due to time-varying cross beam energy transfer, and plasma instability growth near the hohlraum wall.

  14. Controlled Fusion with Hot-ion Mode in a Degenerate Plasma

    Energy Technology Data Exchange (ETDEWEB)

    S. Son and N.J. Fisch

    2005-12-01

    n a Fermi-degenerate plasma, the rate of electron physical processes is much reduced from the classical prediction, possibly enabling new regimes for controlled nuclear fusion, including the hot-ion mode, a regime in which the ion temperature exceeds the electron temperature. Previous calculations of these processes in dense plasmas are now corrected for partial degeneracy and relativistic effects, leading to an expanded regime of self-sustained fusion.

  15. Observed Multi-Decade DD and DT Z-Pinch Fusion Rate Scaling in 5 Dense Plasma Focus Fusion Machines

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, E. C. [National Security Technologies, LLC; Lowe, D. R. [National Security Technologies, LLC; O' Brien, R. [University of Nevada, Las Vegas; Meehan, B. T. [National Security Technologies, LLC

    2013-06-18

    Dense Plasma Focus (DPF) machines are in use worldwide or a wide variety of applications; one of these is to produce intense, short bursts of fusion via r-Z pinch heating and compression of a working gas. We have designed and constructed a series of these, ranging from portable to a maximum energy storage capacity of 2 MJ. Fusion rates from 5 DPF pulsed fusion generators have been measured in a single laboratory using calibrated activation detectors. Measured rates range from ~ 1015 to more than 1019 fusions per second have been measured. Fusion rates from the intense short (20 – 50 ns) periods of production were inferred from measurement of neutron production using both calibrated activation detectors and scintillator-PMT neutron time of flight (NTOF) detectors. The NTOF detectors are arranged to measure neutrons versus time over flight paths of 30 Meters. Fusion rate scaling versus energy and current will be discussed. Data showing observed fusion cutoff at D-D fusion yield levels of approximately 1*1012, and corresponding tube currents of ~ 3 MA will be shown. Energy asymmetry of product neutrons will also be discussed. Data from the NTOF lines of sight have been used to measure energy asymmetries of the fusion neutrons. From this, center of mass energies for the D(d,n)3He reaction are inferred. A novel re-entrant chamber that allows extremely high single pulse neutron doses (> 109 neutrons/cm2 in 50 ns) to be supplied to samples will be described. Machine characteristics and detector types will be discussed.

  16. Fabrication and testing of gas-filled targets for large-scale plasma experiments on nova

    Energy Technology Data Exchange (ETDEWEB)

    Stone, G.F.; Rivers, C.J.; Spragge, M.R.; Wallace, R.J.

    1996-06-01

    The proposed next-generation ICF facility, the National Ignition Facility (NIF) is designed to produce energy gain from x-ray heated {open_quotes}indirect-drive{close_quotes} fuel capsules. For indirect-drive targets, laser light heats the inside of the Au hohlraum wall and produces x rays which in turn heat and implode the capsule to produce fusion conditions in the fuel. Unlike Nova targets, in NIF-scale targets laser light will propagate through several millimeters of gas, producing a plasma, before impinging upon the Au hohlraum wall. The purpose of the gas-produced plasma is to provide sufficient pressure to keep the radiating Au surface from expanding excessively into the hohlraum cavity. Excessive expansion of the Au wall interacts with the laser pulse and degrades the drive symmetry of the capsule implosion. The authors have begun an experimental campaign on the Nova laser to study the effect of hohlraum gas on both laser-plasma interaction and implosion symmetry. In their current NIF target design, the calculated plasma electron temperature is T{sub e} {approx} 3 keV and the electron density is N{sub e} {approx} 10{sup 21}cm{sup {minus}3}.

  17. Dust dynamics and diagnostic applications in quasi-neutral plasmas and magnetic fusion

    Science.gov (United States)

    Wang, Zhehui; Ticos, Catalin M.; Si, Jiahe; Delzanno, Gian Luca; Lapenta, Gianni; Wurden, Glen

    2007-11-01

    Little is known about dust dynamics in highly ionized quasi-neutral plasmas with ca. 1.0 e+20 per cubic meter density and ion temperature at a few eV and above, including in magnetic fusion. For example, dust motion in fusion, better known as UFO's, has been observed since 1980's but not explained. Solid understanding of dust dynamics is also important to International Thermonuclear Experimental Reactor (ITER) because of concerns about safety and dust contamination of fusion core. Compared with well studied strongly-coupled dusty plasma regime, new physics may arise in the higher density quasi-neutral plasma regime because of at least four orders of magnitude higher density and two orders of magnitude hotter ion temperature. Our recent laboratory experiments showed that plasma-flow drag force dominates over other forces in a quasi-neutral flowing plasma. In contrast, delicate balance among different forces in dusty plasma has led to many unique phenomena, in particular, the formation of dust crystal. Based on our experiments, we argue that 1) dust crystal will not form in the highly ionized plasmas with flows; 2) the UFO's are moving dust dragged by plasma flows; 3) dust can be used to measure plasma flow. Two diagnostic applications using dust for laboratory quasi-neutral plasmas and magnetic fusion will also be presented.

  18. Progress towards a more predictive model for hohlraum radiation drive and symmetry

    Science.gov (United States)

    Jones, O. S.; Suter, L. J.; Scott, H. A.; Barrios, M. A.; Farmer, W. A.; Hansen, S. B.; Liedahl, D. A.; Mauche, C. W.; Moore, A. S.; Rosen, M. D.; Salmonson, J. D.; Strozzi, D. J.; Thomas, C. A.; Turnbull, D. P.

    2017-05-01

    For several years, we have been calculating the radiation drive in laser-heated gold hohlraums using flux-limited heat transport with a limiter of 0.15, tabulated values of local thermodynamic equilibrium gold opacity, and an approximate model for not in a local thermodynamic equilibrium (NLTE) gold emissivity (DCA_2010). This model has been successful in predicting the radiation drive in vacuum hohlraums, but for gas-filled hohlraums used to drive capsule implosions, the model consistently predicts too much drive and capsule bang times earlier than measured. In this work, we introduce a new model that brings the calculated bang time into better agreement with the measured bang time. The new model employs (1) a numerical grid that is fully converged in space, energy, and time, (2) a modified approximate NLTE model that includes more physics and is in better agreement with more detailed offline emissivity models, and (3) a reduced flux limiter value of 0.03. We applied this model to gas-filled hohlraum experiments using high density carbon and plastic ablator capsules that had hohlraum He fill gas densities ranging from 0.06 to 1.6 mg/cc and hohlraum diameters of 5.75 or 6.72 mm. The new model predicts bang times to within ±100 ps for most experiments with low to intermediate fill densities (up to 0.85 mg/cc). This model predicts higher temperatures in the plasma than the old model and also predicts that at higher gas fill densities, a significant amount of inner beam laser energy escapes the hohlraum through the opposite laser entrance hole.

  19. Progress of Rugby Hohlraum Experiments on Omega

    Science.gov (United States)

    Philippe, Franck; Tassin, Veronique; Casner, Alexis; Gauthier, Pascal; Seytor, Patricia; Monteil, Marie-Christine; Park, Hye-Sook; Robey, Harry; Ross, Steven; Amendt, Peter; Girard, Frederic; Villette, Bruno; Reverdin, Charles; Loiseau, Pascal; Caillaud, Tony; Landoas, Olivier; Li, Chi Kang; Petrasso, Richard; Seguin, Fredrick; Rosenberg, Markus

    2011-10-01

    The rugby hohlraum concept is predicted to enable better coupling and higher gains in the indirect drive approach to ignition. A collaborative experimental program is currently pursued on OMEGA to test this concept in preparation for future megajoule-scale ignition designs. A direct comparison of gas-filled rugby hohlraums with classical cylinders was recently performed, showing a significant (up to ~40%) observed x-ray drive enhancement and neutron yields that are consistently higher in the rugby case. This work extends and confirms our previous findings in empty rugby hohlraums.

  20. Controlling Laser-Driven Hohlraums-Clues from Experiments with Earlier Lasers

    Science.gov (United States)

    Kruer, William; Thomas, Cliff

    2015-11-01

    Better characterized and controlled hohlraums are very important for both implosion and science experiments on NIF. A brief review of some hohlraum and related experiments with earlier lasers is given to search for lessons learned and clues for better understanding NIF hohlraums. For example, surprises associated with heat transport inhibition and improved models for radiation generation have been a recurring theme in indirect drive experiments. In Shiva experiments, the hohlraum filling with plasma with density near quarter-critical was only calculated after inhibited heat transport and improved radiation models were adopted in the design code. Early NIF experiments also led to a change in the heat transport and radiation models. In this case, the heat transport model was changed from one with modest inhibition (which had been used to model Nova experiments) to near classical transport. Most recently, a design model invoking very inhibited transport (at various times and locations) has been proposed by C. Thomas for NIF hohlraums. Other recurring themes will also be discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  1. O-d energetics scaling models for Z-pinch-driven hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    CUNEO,MICHAEL E.; VESEY,ROGER A.; HAMMER,J.H.; PORTER,JOHN L.

    2000-06-08

    Wire array Z-pinches on the Z accelerator provide the most intense laboratory source of soft x-rays in the world. The unique combination of a highly-Planckian radiation source with high x-ray production efficiency (15% wall plug), large x-ray powers and energies ( >150 TW, {ge}1 MJ in 7 ns), large characteristic hohlraum volumes (0.5 to >10 cm{sup 3}), and long pulse-lengths (5 to 20 ns) may make Z-pinches a good match to the requirements for driving high-yield scale ICF capsules with adequate radiation symmetry and margin. The Z-pinch driven hohlraum approach of Hammer and Porter [Phys.Plasmas, 6, 2129(1999)] may provide a conservative and robust solution to the requirements for high yield, and is currently being studied on the Z accelerator. This paper describes a multiple region, 0-d hohlraum energetic model for Z-pinch driven hohlraums in four configurations. The authors observe consistency between the models and the measured x-ray powers and hohlraum wall temperatures to within {+-}20% in flux, for the four configurations.

  2. Direct-drive Energetics of laser-Heated Foam Liners for Hohlraums

    Science.gov (United States)

    Moore, Alastair; Thomas, Cliff; Baker, Kevin; Morton, John; Baumann, Ted; Biener, Monika; Bhandarkar, Suhas; Hinkel, Denise; Jones, Oggie; Meezan, Nathan; Moody, John; Nikroo, Abbas; Rosen, Mordy; Hsing, Warren

    2016-10-01

    Lining the walls of a high-Z hohlraum cavity with a low-density foam is predicted to mitigate the challenge presented by hohlraum wall expansion. Once heated, wall material quickly fills the cavity and can impede laser beam propagation. To avoid this, ignition hohlraums are typically filled with a gas or irradiated with a short (laser pulse. A gas-fill has the disadvantage that it can cause laser plasma instabilities (LPI), while a short laser pulse limits the design space to reach low-adiabat implosions. Foam-liners offer a potential route to reduce wall motion in a low gas-fill hohlraum with little LPI. Results from quasi 1-D experiments performed at the NIF are presented These characterize the x-ray conversion efficiency, backscattered laser energy and heat propagation in a 250 μm thick Ta2O5 or ZnO foam-liners spanning a range of densities from underdense to overdense, when irradiated at up to 4.9 x 1014 W/cm2 is incident on a planar foam sample, backed by a Au foil and generates a radiation temperature of up to 240eV - conditions equivalent to a single outer cone beam-spot in an ignition hohlraum. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  3. Towards Real-Time Detection and Tracking of Blob-Filaments in Fusion Plasma Big Data

    CERN Document Server

    Wu, Lingfei; Sim, Alex; Churchill, Michael; Choi, Jong Y; Stathopoulos, Andreas; Chang, Cs; Klasky, Scott

    2015-01-01

    Magnetic fusion could provide an inexhaustible, clean, and safe solution to the global energy needs. The success of magnetically-confined fusion reactors demands steady-state plasma confinement which is challenged by the blob-filaments driven by the edge turbulence. Real-time analysis can be used to monitor the progress of fusion experiments and prevent catastrophic events. However, terabytes of data are generated over short time periods in fusion experiments. Timely access to and analyzing this amount of data demands properly responding to extreme scale computing and big data challenges. In this paper, we apply outlier detection techniques to effectively tackle the fusion blob detection problem on extremely large parallel machines. We present a real-time region outlier detection algorithm to efficiently find blobs in fusion experiments and simulations. In addition, we propose an efficient scheme to track the movement of region outliers over time. We have implemented our algorithms with hybrid MPI/OpenMP and ...

  4. Radiation transport and energetics of laser-driven half-hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Moore, A. S. [Directorate Science and Technology, AWE Aldermaston, Reading (United Kingdom); Cooper, A. B.R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schneider, M. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); MacLaren, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Graham, P. [Directorate Science and Technology, AWE Aldermaston, Reading (United Kingdom); Lu, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Seugling, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Satcher, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Klingmann, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Comley, A. J. [Directorate Science and Technology, AWE Aldermaston, Reading (United Kingdom); Marrs, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); May, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Widmann, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glendinning, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Castor, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sain, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Back, C. A. [General Atomics, San Diego, CA (United States); Hund, J. [General Atomics, San Diego, CA (United States); Baker, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hsing, W. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Foster, J. [Directorate Science and Technology, AWE Aldermaston, Reading (United Kingdom); Young, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Young, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-06-01

    Experiments that characterize and develop a high energy-density half-hohlraum platform for use in bench-marking radiation hydrodynamics models have been conducted at the National Ignition Facility (NIF). Results from the experiments are used to quantitatively compare with simulations of the radiation transported through an evolving plasma density structure, colloquially known as an N-wave. A half-hohlraum is heated by 80 NIF beams to a temperature of 240 eV. This creates a subsonic di usive Marshak wave which propagates into a high atomic number Ta2O5 aerogel. The subsequent radiation transport through the aerogel and through slots cut into the aerogel layer is investigated. We describe a set of experiments that test the hohlraum performance and report on a range

  5. Radiation transport and energetics of laser-driven half-hohlraums at the National Ignition Facility

    Science.gov (United States)

    Moore, A. S.; Cooper, A. B. R.; Schneider, M. B.; MacLaren, S.; Graham, P.; Lu, K.; Seugling, R.; Satcher, J.; Klingmann, J.; Comley, A. J.; Marrs, R.; May, M.; Widmann, K.; Glendinning, G.; Castor, J.; Sain, J.; Back, C. A.; Hund, J.; Baker, K.; Hsing, W. W.; Foster, J.; Young, B.; Young, P.

    2014-06-01

    Experiments that characterize and develop a high energy-density half-hohlraum platform for use in benchmarking radiation hydrodynamics models have been conducted at the National Ignition Facility (NIF). Results from the experiments are used to quantitatively compare with simulations of the radiation transported through an evolving plasma density structure, colloquially known as an N-wave. A half-hohlraum is heated by 80 NIF beams to a temperature of 240 eV. This creates a subsonic diffusive Marshak wave, which propagates into a high atomic number Ta2O5 aerogel. The subsequent radiation transport through the aerogel and through slots cut into the aerogel layer is investigated. We describe a set of experiments that test the hohlraum performance and report on a range of x-ray measurements that absolutely quantify the energetics and radiation partition inside the target.

  6. Analysis of hohlraum energetics of the SG series and the NIF experiments with energy balance model

    Directory of Open Access Journals (Sweden)

    Guoli Ren

    2017-01-01

    Full Text Available The basic energy balance model is applied to analyze the hohlraum energetics data from the Shenguang (SG series laser facilities and the National Ignition Facility (NIF experiments published in the past few years. The analysis shows that the overall hohlraum energetics data are in agreement with the energy balance model within 20% deviation. The 20% deviation might be caused by the diversity in hohlraum parameters, such as material, laser pulse, gas filling density, etc. In addition, the NIF's ignition target designs and our ignition target designs given by simulations are also in accordance with the energy balance model. This work confirms the value of the energy balance model for ignition target design and experimental data assessment, and demonstrates that the NIF energy is enough to achieve ignition if a 1D spherical radiation drive could be created, meanwhile both the laser plasma instabilities and hydrodynamic instabilities could be suppressed.

  7. Plasma system requirements and performance data base for the Starlite/Demo fusion power plant

    Energy Technology Data Exchange (ETDEWEB)

    Mau, T.K.; Lee, B.J. [Univ. of California, San Diego, La Jolla, CA (United States). Fusion Energy Research Program; Ehst, D.A. [Argonne National Lab., IL (United States); Jardin, S.C.; Kessel, C.E. [Princeton Plasma Physics Lab., NJ (United States)

    1995-12-31

    General plasma system requirements for the US Demo fusion power plant have been identified, taking into account factors of economics, operability and reliability. Required extrapolations from the present plasma performance database have been assessed for the Demo options in five areas of tokamak operation, namely, stability, current drive, energy confinement, heat exhaust, and ash removal, for which figures of merit have been identified.

  8. Contributed papers presented at the 24. EPS conference on controlled fusion and plasma physics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    In the report thirteen papers are compiled which were presented by members of the Centre de Recherches en Physique des Plasma, Lausanne, at the 24th EPS conference on controlled fusion and plasma physics. They mainly deal with problems of the confinement and are based on studies performed in the TCV tokamak. figs., tabs., refs.

  9. High precision measurement of fuel density profiles in nuclear fusion plasmas

    NARCIS (Netherlands)

    Svensson, J.; von Hellermann, M.; Konig, R.

    2002-01-01

    This paper presents a method for deducing fuel density profiles of nuclear fusion plasmas in realtime during an experiment. A Multi Layer Perceptron (MLP) neural network is used to create a mapping between plasma radiation spectra and indirectly deduced hydrogen isotope densities. By combining diffe

  10. Diagnosis of energetic ions and ion composition in fusion plasmas by collective Thomson scattering of mm-waves

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Korsholm, Søren Bang; Leipold, Frank;

    2012-01-01

    In fusion plasmas, the dominant heating source will be fusion generated energetic ions slowing down in the plasma. The same ions can also drive waves and instabilities in the plasma. Their distribution in velocity and in space has major impact on plasma dynamics, and plasma dynamics in turn affects...... the energetic ion distributions. The dynamics of energetic ions is thus important to measure in order to understand fusion plasmas, and important to monitor as part of input to plasma control. The collective Thomson scattering of millimeter waves has proven to be a valuable means of diagnosing energetic ion...... distributions in fusion plasmas1,2. A beam of mm-waves with a diameter of 5–10 cm and a power of 150–600 kW is sent through the plasma, and radiation scattered from this probe beam by the microscopic fluctuations in the plasma is detected. These microscopic fluctuations are in part induced by the ion motion...

  11. Fusion plasma diagnostics with mm-waves an introduction

    CERN Document Server

    Hartfuss, Hans-Jürgen

    2013-01-01

    Filling a gap in the literature, this introduction to the topic covers the physics of the standard microwave diagnostics established on modern fusion experiments, and the necessary technological background from the field of microwave engineering. Written by well-known mm-wave diagnosticians in the field of fusion physics, the textbook includes such major diagnostic techniques as electron cyclotron emission, interferometry, reflectometry, polarimetry, and scattering.

  12. Optical Mixing in the Strong Coupling Regime: A New Method of Beam Conditioning at Hohlraum LEH and Direct Drive ICF Coronal Plasmas

    Science.gov (United States)

    Mardirian, Marine; Afeyan, Bedros; Huller, Stefan; Montgomery, David; Froula, Dustin; Kirkwood, Robert

    2012-10-01

    We will present theoretical and computational results on Brillouin interactions between two beams in co-, counter-, and orthogonal propagation geometries. The beams will be structured (with speckle patterns), the plasma will have inhomogeneous flow including the Mach -1 surface. As the growth rate of the instability surpasses the natural frequency of the ion wave, the strong coupling regime (SCR) is reached, where reactive quasi-modes with intensity dependent frequency shifts result. This is especially true in laser hot spots. We trace the consequences of operations in this regime with different damping rates on the ion acoustic waves. We consider convective and absolute instabilities as well as the design of experiments which could examine these new regimes of instability behavior with new 10 psec time resolved diagnostics. Whether well enough conditioned beams can result after 10's or 100's of pairwise crossings in direct and indirect drive ICF configurations, and whether SRS can thus be strongly suppressed downstream, remains to be demonstrated. But the prospects exist for such new paths to instability control in a staged manner before STUD pulses are implemented.-

  13. NATO Advanced Study Institute entitled Physics of Plasma-Wall Interactions in Controlled Fusion

    CERN Document Server

    Behrisch, R; Physics of plasma-wall interactions in controlled fusion

    1986-01-01

    Controlled thermonuclear fusion is one of the possible candidates for long term energy sources which will be indispensable for our highly technological society. However, the physics and technology of controlled fusion are extremely complex and still require a great deal of research and development before fusion can be a practical energy source. For producing energy via controlled fusion a deuterium-tritium gas has to be heated to temperatures of a few 100 Million °c corres­ ponding to about 10 keV. For net energy gain, this hot plasma has to be confined at a certain density for a certain time One pro­ mising scheme to confine such a plasma is the use of i~tense mag­ netic fields. However, the plasma diffuses out of the confining magnetic surfaces and impinges on the surrounding vessel walls which isolate the plasma from the surrounding air. Because of this plasma wall interaction, particles from the plasma are lost to the walls by implantation and are partially reemitted into the plasma. In addition, wall...

  14. Binding and Fusion of Extracellular Vesicles to the Plasma Membrane of Their Cell Targets.

    Science.gov (United States)

    Prada, Ilaria; Meldolesi, Jacopo

    2016-08-09

    Exosomes and ectosomes, extracellular vesicles of two types generated by all cells at multivesicular bodies and the plasma membrane, respectively, play critical roles in physiology and pathology. A key mechanism of their function, analogous for both types of vesicles, is the fusion of their membrane to the plasma membrane of specific target cells, followed by discharge to the cytoplasm of their luminal cargo containing proteins, RNAs, and DNA. Here we summarize the present knowledge about the interactions, binding and fusions of vesicles with the cell plasma membrane. The sequence initiates with dynamic interactions, during which vesicles roll over the plasma membrane, followed by the binding of specific membrane proteins to their cell receptors. Membrane binding is then converted rapidly into fusion by mechanisms analogous to those of retroviruses. Specifically, proteins of the extracellular vesicle membranes are structurally rearranged, and their hydrophobic sequences insert into the target cell plasma membrane which undergoes lipid reorganization, protein restructuring and membrane dimpling. Single fusions are not the only process of vesicle/cell interactions. Upon intracellular reassembly of their luminal cargoes, vesicles can be regenerated, released and fused horizontally to other target cells. Fusions of extracellular vesicles are relevant also for specific therapy processes, now intensely investigated.

  15. Thermionic plasma injection for the Lockheed Martin T4 Compact Fusion Reactor experiment

    Science.gov (United States)

    Heinrich, Jonathon

    2015-11-01

    Lockheed Martin's Compact Fusion Reactor (CFR) concept relies on diamagnetic confinement in a magnetically encapsulated linear ring cusp geometry. Plasma injection into cusp field configurations requires careful deliberation. Previous work has shown that axial injection via a plasma gun is capable of achieving high-beta conditions in cusp configurations. We present a pulsed, high power thermionic plasma source and the associated magnetic field topology for plasma injection into the caulked-cusp magnetic field. The resulting plasma fueling and cross-field diffusion is discussed.

  16. Cylindrical target Li-beam-driven hohlraum experiments

    Energy Technology Data Exchange (ETDEWEB)

    Derzon, M.S.; Aubert, J.; Chandler, G.A. [and others

    1998-06-01

    The authors performed a series of experiments on the Particle Beam Fusion Accelerator II (PBFA II) in May, 1994, and obtained a brightness temperature of 61 {+-} 2 eV for an ion-beam heated hohlraum. The hohlraum was a 4-mm-diameter, right-circular cylinder with a 1.5-mm-thick gold wall, a low-density CH foam fill, and a 1.5- or 3-mm-diameter diagnostic aperture in the top. The nominal parameters of the radially-incident PBFA II Li ion beam were 9 MeV peak energy ({approximately}10 MeV at the gas cell) at the target at a peak power of 2.5 {+-} 0.3 TW/cm{sup 2} and a 15 ns pulse width. Azimuthal variations in intensity of a factor of 3, with respect to the mean, were observed. Nonuniformities in thermal x-ray emission across the area of the diagnostic hole were also observed. Time-dependent hole-closure velocities were measured: the time-averaged velocity of {approximately}2 cm/{micro}s is in good agreement with sound speed estimates. Unfolded x-ray spectra and brightness temperatures as a function of time are reported and compared to simulations. Hole closure corrections are discussed with comparisons between XRD and bolometer measurements. Temperature scaling with power on target is also presented.

  17. Planar hydrodynamic instability computations and experiments with rugby-shaped hohlraums at the Omega laser

    Science.gov (United States)

    Vandenboomgaerde, M.; Liberatore, S.; Galmiche, D.; Casner, A.; Huser, G.; Jadaud, J. P.; Villette, B.

    2008-05-01

    Implosion of inertial confinement fusion (ICF) capsule is very sensitive to the growth of sphericity perturbations. The control of the feeding of such perturbations and their transport ('feedthrough') through the ablator is a key point to reach ignition. Since 2002 [1, 2], experiments have been designed and performed on the Omega laser facility in order to study these phenomena in planar geometry. A new 'rugby shaped' hohlraum was used [3, 4]. We present experimental results and comparisons with numerical simulations.

  18. Surface analysis of CVD diamond exposed to fusion plasma

    NARCIS (Netherlands)

    Porro, S.; De Temmerman, G.; MacLaren, D. A.; Lisgo, S.; Rudakov, D. L.; Westerhout, J.; Wiora, M.; John, P.; Villalpando, I.; Wilson, J. I. B.

    2010-01-01

    Microcrystalline undoped and heavily boron-doped polycrystalline diamond layers have been deposited on various substrates by hot filament CVD and exposed to hydrogen plasma in a linear plasma reactor (Pilot-PSI, The Netherlands) that simulates the high flux and high density plasma conditions of toka

  19. Nuclear Fusion in Laser-Driven Counter-Streaming Collisionless Plasmas

    CERN Document Server

    Zhang, Xiaopeng; Yuan, Dawei; Fu, Changbo; Bao, Jie; Chen, Liming; He, Jianjun; Hou, Long; Li, Liang; Li, Yanfei; Li, Yutong; Liao, Guoqiang; Rhee, Yongjoo; Sun, Yang; Xu, Skiwei; Zhao, Gang; Zhu, Baojun; Zhu, Jianqiang; Zhang, Zhe; Zhang, Jie

    2016-01-01

    Nuclear fusion reactions are the most important processes in nature to power stars and produce new elements, and lie at the center of the understanding of nucleosynthesis in the universe. It is critically important to study the reactions in full plasma environments that are close to true astrophysical conditions. By using laser-driven counter-streaming collisionless plasmas, we studied the fusion D$+$D$\\rightarrow n +^3$He in a Gamow-like window around 27 keV. The results show that astrophysical nuclear reaction yield can be modulated significantly by the self-generated electromagnetic fields and the collective motion of the plasma. This plasma-version mini-collider may provide a novel tool for studies of astrophysics-interested nuclear reactions in plasma with tunable energies in earth-based laboratories.

  20. Helium-3 Generation from the Interaction of Deuterium Plasma inside a Hydrogenated Lattice: Red Fusion

    Science.gov (United States)

    Leal-Quiros, Edbertho; Leal-Escalante, David A.

    2015-03-01

    Helium-3 has been created in a nuclear fusion reaction by fusing deuterium ions from deuterium plasma with hydrogen ions in a “RED” (the Spanish word for net) or crystal lattice, a method we called red fusion ("Fusion en la red cristalina"), because is a new method to make nuclear fusion reaction. In this paper, it will be show the experimental results where the helium-3 has been generated for the first time in this kind of new method to confine deuterium and hydrogen inside the RED or lattice of the hydrogenated crystal and that confinement inside the RED facilitated overcoming the Coulomb barrier between them and helium-3 and phonons are produced in this fusion reaction. The results of a long time research in which helium-3, has been created in a fusion reaction inside the lattice or RED of the crystal that contained hydrogen after adequate interaction of deuterium plasma at appropriate high temperature and magnetic confinement of the Mirror/Cusp Plasma Machine at Polytechnic University of Puerto Rico, designed by the authors. Several mass spectra and visible light spectrum where the presence of helium-3 was detected are shown. The experiment was repeated more than 200 times showing always the generation of helium-3. In this experiment no gamma rays were detected. For this experiment several diagnostic instruments were used. The data collection with these control instrumentation are shown. Thus, it is an important new way to generate Helium-3. reserved.

  1. Differential cargo mobilisation within Weibel-Palade bodies after transient fusion with the plasma membrane.

    Directory of Open Access Journals (Sweden)

    Nikolai I Kiskin

    Full Text Available Inflammatory chemokines can be selectively released from Weibel-Palade bodies (WPBs during kiss-and-run exocytosis. Such selectivity may arise from molecular size filtering by the fusion pore, however differential intra-WPB cargo re-mobilisation following fusion-induced structural changes within the WPB may also contribute to this process. To determine whether WPB cargo molecules are differentially re-mobilised, we applied FRAP to residual post-fusion WPB structures formed after transient exocytosis in which some or all of the fluorescent cargo was retained. Transient fusion resulted in WPB collapse from a rod to a spheroid shape accompanied by substantial swelling (>2 times by surface area and membrane mixing between the WPB and plasma membranes. Post-fusion WPBs supported cumulative WPB exocytosis. To quantify diffusion inside rounded organelles we developed a method of FRAP analysis based on image moments. FRAP analysis showed that von Willebrand factor-EGFP (VWF-EGFP and the VWF-propolypeptide-EGFP (Pro-EGFP were immobile in post-fusion WPBs. Because Eotaxin-3-EGFP and ssEGFP (small soluble cargo proteins were largely depleted from post-fusion WPBs, we studied these molecules in cells preincubated in the weak base NH4Cl which caused WPB alkalinisation and rounding similar to that produced by plasma membrane fusion. In these cells we found a dramatic increase in mobilities of Eotaxin-3-EGFP and ssEGFP that exceeded the resolution of our method (∼ 2.4 µm2/s mean. In contrast, the membrane mobilities of EGFP-CD63 and EGFP-Rab27A in post-fusion WPBs were unchanged, while P-selectin-EGFP acquired mobility. Our data suggest that selective re-mobilisation of chemokines during transient fusion contributes to selective chemokine secretion during transient WPB exocytosis. Selective secretion provides a mechanism to regulate intravascular inflammatory processes with reduced risk of thrombosis.

  2. Differential cargo mobilisation within Weibel-Palade bodies after transient fusion with the plasma membrane.

    Science.gov (United States)

    Kiskin, Nikolai I; Babich, Victor; Knipe, Laura; Hannah, Matthew J; Carter, Tom

    2014-01-01

    Inflammatory chemokines can be selectively released from Weibel-Palade bodies (WPBs) during kiss-and-run exocytosis. Such selectivity may arise from molecular size filtering by the fusion pore, however differential intra-WPB cargo re-mobilisation following fusion-induced structural changes within the WPB may also contribute to this process. To determine whether WPB cargo molecules are differentially re-mobilised, we applied FRAP to residual post-fusion WPB structures formed after transient exocytosis in which some or all of the fluorescent cargo was retained. Transient fusion resulted in WPB collapse from a rod to a spheroid shape accompanied by substantial swelling (>2 times by surface area) and membrane mixing between the WPB and plasma membranes. Post-fusion WPBs supported cumulative WPB exocytosis. To quantify diffusion inside rounded organelles we developed a method of FRAP analysis based on image moments. FRAP analysis showed that von Willebrand factor-EGFP (VWF-EGFP) and the VWF-propolypeptide-EGFP (Pro-EGFP) were immobile in post-fusion WPBs. Because Eotaxin-3-EGFP and ssEGFP (small soluble cargo proteins) were largely depleted from post-fusion WPBs, we studied these molecules in cells preincubated in the weak base NH4Cl which caused WPB alkalinisation and rounding similar to that produced by plasma membrane fusion. In these cells we found a dramatic increase in mobilities of Eotaxin-3-EGFP and ssEGFP that exceeded the resolution of our method (∼ 2.4 µm2/s mean). In contrast, the membrane mobilities of EGFP-CD63 and EGFP-Rab27A in post-fusion WPBs were unchanged, while P-selectin-EGFP acquired mobility. Our data suggest that selective re-mobilisation of chemokines during transient fusion contributes to selective chemokine secretion during transient WPB exocytosis. Selective secretion provides a mechanism to regulate intravascular inflammatory processes with reduced risk of thrombosis.

  3. Radiation-MHD Simulations of Plasma-Jet-Driven Magneto-Inertial Fusion Gain Using USim

    Science.gov (United States)

    Stoltz, Peter; Beckwith, Kristian; Kundrapu, Mahdusudhan; Hsu, Scott; Langendorf, Samuel

    2016-10-01

    One goal of the modeling effort for the PLX- α project is to identify plasma-jet-driven magneto-inertial fusion (PJMIF) configurations with potential net fusion-energy gain. We use USim, which is a tool for modeling high-energy-density plasmas using multi-fluid models coupled to electromagnetics using fully-implicit iterative solvers, combined with finite volume discretizations on unstructured meshes. We include physical viscosity and advanced-EOS modeling capability, and are investigating the effects of different radiation (including flux-limited diffusion) and alpha-transport models. We compare 2D and 1D gain calculations for various liner geometries, parameters, and plasma species, and consider the effects of liner non-uniformities on fusion-gain degradation. Supported by the ARPA-E ALPHA Program.

  4. High Performance Capsule Implosions on the Omega Laser Facility with Rugby Hohlraums

    Science.gov (United States)

    Robey, Harry F.

    2009-11-01

    Rugby-shaped hohlraums have been proposed as a method for x-ray drive enhancement for indirectly-driven capsule implosions [1]. This concept has recently been tested in a series of shots on the OMEGA laser facility at the Laboratory for Laser Energetics at the University of Rochester. In this talk, experimental results are presented comparing the performance of D2-filled capsules between standard cylindrical Au hohlraums and rugby-shaped hohlraums. Not only did the rugby hohlraums demonstrate 18% more x-ray drive energy as compared with the cylinders, but the high-performance design of these implosions (both cylinder and rugby) also provided 20X more DD neutrons than any previous indirectly-driven campaign on Omega (and 3X more than ever achieved on Nova implosions driven with nearly twice the laser energy). This increase in performance enables, for the first time, a measurement of the neutron burn history of an indirectly-driven implosion. Previous DD neutron yields had been too low to register this key measurement of capsule performance and the effects of dynamic mix. A wealth of additional data on the fuel areal density from the suite of charged particle diagnostics was obtained on a subset of the shots that used D^3He rather than D2 fuel. Comparisons of the experimental results with numerical simulations are shown to be in excellent agreement. The design techniques employed in this campaign, e.g., smaller NIF-like laser entrance holes and hohlraum case-to-capsule ratios, provide added confidence in the pursuit of ignition on the National Ignition Facility. [4pt] [1] P. Amendt, C. Cerjan, D. E. Hinkel, J. L. Milovich, H.-S. Park, and H. F. Robey, ``Rugby-like hohlraum experimental designs for demonstrating x-ray drive enhancement'', Phys. Plasmas 15, 012702 (2008).

  5. Study of Plasma Liner Driven Magnetized Target Fusion Via Advanced Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Samulyak, Roman V. [State Univ. of New York (SUNY), Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States); Parks, Paul [General Atomics, San Diego, CA (United States)

    2013-08-31

    The feasibility of the plasma liner driven Magnetized Target Fusion (MTF) via terascale numerical simulations will be assessed. In the MTF concept, a plasma liner, formed by merging of a number (60 or more) of radial, highly supersonic plasma jets, implodes on the target in the form of two compact plasma toroids, and compresses it to conditions of the fusion ignition. By avoiding major difficulties associated with both the traditional laser driven inertial confinement fusion and solid liner driven MTF, the plasma liner driven MTF potentially provides a low-cost and fast R&D path towards the demonstration of practical fusion energy. High fidelity numerical simulations of full nonlinear models associated with the plasma liner MTF using state-of-art numerical algorithms and terascale computing are necessary in order to resolve uncertainties and provide guidance for future experiments. At Stony Brook University, we have developed unique computational capabilities that ideally suite the MTF problem. The FronTier code, developed in collaboration with BNL and LANL under DOE funding including SciDAC for the simulation of 3D multi-material hydro and MHD flows, has beenbenchmarked and used for fundamental and engineering problems in energy science applications. We have performed 3D simulations of converging supersonic plasma jets, their merger and the formation of the plasma liner, and a study of the corresponding oblique shock problem. We have studied the implosion of the plasma liner on the magnetized plasma target by resolving Rayleigh-Taylor instabilities in 2D and 3D and other relevant physics and estimate thermodynamic conditions of the target at the moment of maximum compression and the hydrodynamic efficiency of the method.

  6. Effects of a liquid lithium curtain as the first wall in a fusion reactor plasma

    Institute of Scientific and Technical Information of China (English)

    Li Cheng-Yue; J.P. Allain; Deng Bai-Quan

    2007-01-01

    This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder (FEB-E). The relationships between the surface temperature of a liquid lithium curtain and the effective plasma charge, fuel dilution and fusion power production have been derived. Results indicate that under normal operation, the evaporation of liquid lithium does not seriously affect the effective plasma charge, but effects on fuel dilution and fusion power are more sensitive. As an example, it has investigated the relationships between the liquid lithium curtain flow velocity and the rise of surface temperature based on operation scenario Ⅱ of the FEB-E design with reversed shear configuration and high power density. Results show that even if the liquid lithium curtain flow velocity is as low as 0.5 m/s, the effects of evaporation from the liquid lithium curtain on plasma are negligible. In the present design, the sputtering of liquid lithium curtain and the particle removal effects of the divertor are not yet considered in detail. Further studies are in progress, and in this work implication of lithium erosion and divertor physics on fusion reactor operation are discussed.

  7. Phase space structures in gyrokinetic simulations of fusion plasma turbulence

    Science.gov (United States)

    Ghendrih, Philippe; Norscini, Claudia; Cartier-Michaud, Thomas; Dif-Pradalier, Guilhem; Abiteboul, Jérémie; Dong, Yue; Garbet, Xavier; Gürcan, Ozgür; Hennequin, Pascale; Grandgirard, Virginie; Latu, Guillaume; Morel, Pierre; Sarazin, Yanick; Storelli, Alexandre; Vermare, Laure

    2014-10-01

    Gyrokinetic simulations of fusion plasmas give extensive information in 5D on turbulence and transport. This paper highlights a few of these challenging physics in global, flux driven simulations using experimental inputs from Tore Supra shot TS45511. The electrostatic gyrokinetic code GYSELA is used for these simulations. The 3D structure of avalanches indicates that these structures propagate radially at localised toroidal angles and then expand along the field line at sound speed to form the filaments. Analysing the poloidal mode structure of the potential fluctuations (at a given toroidal location), one finds that the low modes m = 0 and m = 1 exhibit a global structure; the magnitude of the m = 0 mode is much larger than that of the m = 1 mode. The shear layers of the corrugation structures are thus found to be dominated by the m = 0 contribution, that are comparable to that of the zonal flows. This global mode seems to localise the m = 2 mode but has little effect on the localisation of the higher mode numbers. However when analysing the pulsation of the latter modes one finds that all modes exhibit a similar phase velocity, comparable to the local zonal flow velocity. The consequent dispersion like relation between the modes pulsation and the mode numbers provides a means to measure the zonal flow. Temperature fluctuations and the turbulent heat flux are localised between the corrugation structures. Temperature fluctuations are found to exhibit two scales, small fluctuations that are localised by the corrugation shear layers, and appear to bounce back and forth radially, and large fluctuations, also readily observed on the flux, which are associated to the disruption of the corrugations. The radial ballistic velocity of both avalanche events if of the order of 0.5ρ∗c0 where ρ∗ = ρ0/a, a being the tokamak minor radius and ρ0 being the characteristic Larmor radius, ρ0 = c0/Ω0. c0 is the reference ion thermal velocity and Ω0 = qiB0/mi the reference

  8. Thermonuclear reactivity of D-T fusion plasma with spin-polarized fuel

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Toshiki [Department of Electronic Engineering, Gunma Univ., Kiryu, Gunma (Japan); Nakao, Yasuyuki

    1999-04-01

    The thermonuclear reactivity of deuterium(D) - tritium(T) fusion plasma with spin-polarized fuel has been studied. Two mechanisms of depolarization, collisions and waves, in the high temperature fusion plasma have been considered. The binary collisions have been found not to change the nuclear spin states. The waves with a frequency of a few GHz, however, changes the spin states appreciably, when {delta}B/B{sub 0} (the ratio of the amplitude of the fluctuating magnetic field to the external field) becomes larger than 10{sup -5}. (author)

  9. Stimulated emission of fast Alfv\\'en waves within magnetically confined fusion plasmas

    CERN Document Server

    Cook, J W S; Chapman, S C

    2016-01-01

    A fast Alfv\\'en wave with finite amplitude is shown to grow by a stimulated emission process that we propose for exploitation in toroidal magnetically confined fusion plasmas. Stimulated emission occurs while the wave propagates inward through the outer mid-plane plasma, where a population inversion of the energy distribution of fusion-born ions is observed to arise naturally. Fully nonlinear first principles simulations, which self-consistently evolve particles and fields under the Maxwell-Lorentz system, demonstrate this novel "alpha-particle channelling" scenario for the first time.

  10. Stimulated Emission of Fast Alfvén Waves within Magnetically Confined Fusion Plasmas

    Science.gov (United States)

    Cook, J. W. S.; Dendy, R. O.; Chapman, S. C.

    2017-05-01

    A fast Alfvén wave with a finite amplitude is shown to grow by a stimulated emission process that we propose for exploitation in toroidal magnetically confined fusion plasmas. Stimulated emission occurs while the wave propagates inward through the outer midplane plasma, where a population inversion of the energy distribution of fusion-born ions is observed to arise naturally. Fully nonlinear first-principles simulations, which self-consistently evolve particles and fields under the Maxwell-Lorentz system, demonstrate this novel "α -particle channeling" scenario for the first time.

  11. 13th EU-US Transport Task Force Workshop on transport in fusion plasmas

    DEFF Research Database (Denmark)

    Connor, J.W.; Fasoli, A.; Hidalgo, C.

    2009-01-01

    This report summarizes the contributions presented at the 13th EU-US Transport Task Force Workshop on transport in fusion plasmas, held in Copenhagen, Denmark, 1-4 September 2008. There were sessions on core heat and particle transport; core and edge momentum transport; edge and scrape-off-layer ......This report summarizes the contributions presented at the 13th EU-US Transport Task Force Workshop on transport in fusion plasmas, held in Copenhagen, Denmark, 1-4 September 2008. There were sessions on core heat and particle transport; core and edge momentum transport; edge and scrape...

  12. Fusion

    CERN Document Server

    Mahaffey, James A

    2012-01-01

    As energy problems of the world grow, work toward fusion power continues at a greater pace than ever before. The topic of fusion is one that is often met with the most recognition and interest in the nuclear power arena. Written in clear and jargon-free prose, Fusion explores the big bang of creation to the blackout death of worn-out stars. A brief history of fusion research, beginning with the first tentative theories in the early 20th century, is also discussed, as well as the race for fusion power. This brand-new, full-color resource examines the various programs currently being funded or p

  13. Study of plasma equilibrium in toroidal fusion devices using mesh-free numerical calculation method

    Science.gov (United States)

    Rasouli, C.; Abbasi Davani, F.; Rokrok, B.

    2016-08-01

    Plasma confinement using external magnetic field is one of the successful ways leading to the controlled nuclear fusion. Development and validation of the solution process for plasma equilibrium in the experimental toroidal fusion devices is the main subject of this work. Solution of the nonlinear 2D stationary problem as posed by the Grad-Shafranov equation gives quantitative information about plasma equilibrium inside the vacuum chamber of hot fusion devices. This study suggests solving plasma equilibrium equation which is essential in toroidal nuclear fusion devices, using a mesh-free method in a condition that the plasma boundary is unknown. The Grad-Shafranov equation has been solved numerically by the point interpolation collocation mesh-free method. Important features of this approach include truly mesh free, simple mathematical relationships between points and acceptable precision in comparison with the parametric results. The calculation process has been done by using the regular and irregular nodal distribution and support domains with different points. The relative error between numerical and analytical solution is discussed for several test examples such as small size Damavand tokamak, ITER-like equilibrium, NSTX-like equilibrium, and typical Spheromak.

  14. Magnetic Probe to Study Plasma Jets for Magneto-Inertial Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Martens, Daniel [Los Alamos National Laboratory; Hsu, Scott C. [Los Alamos National Laboratory

    2012-08-16

    A probe has been constructed to measure the magnetic field of a plasma jet generated by a pulsed plasma rail-gun. The probe consists of two sets of three orthogonally-oriented commercial chip inductors to measure the three-dimensional magnetic field vector at two separate positions in order to give information about the magnetic field evolution within the jet. The strength and evolution of the magnetic field is one of many factors important in evaluating the use of supersonic plasma jets for forming imploding spherical plasma liners as a standoff driver for magneto-inertial fusion.

  15. State of Modeling Symmetry in Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-22

    Modeling radiation drive asymmetry is challenging problem whose agreement with data depends on the hohlraum gas fill density. Modeling to date uses the HYDRA code with crossbeam energy transfer (CBET) calculated separately, and backscattered light removed from the input laser. For high fill hohlraums (~>1 mg/cc), matching symmetry requires ad hoc adjustments to CBET during picket and peak of drive. For near-vacuum hohlraums, there is little CBET or backscatter, and drive is more waist-high than predicted. For intermediate fill densities (~0.6 mg/cc) there appears to be a region of small CBET and backscatter where symmetry is reasonably well modeled. A new technique where backscatter and CBET are done “inline” appears it could bring high fill simulations closer to data.

  16. Inertial Electrostatic Confinement (IEC) Fusion using Helicon Injected Plasma Source

    Science.gov (United States)

    Miley, George; Ahern, Drew; Bowman, Jaerd

    2016-10-01

    The use of an external plasma source with the IEC has the advantage that the background pressure in the IEC chamber can be low. This then enables a deep potential well formation for ion confinement. Also unit efficiency is increase due to minimization of ion losses through charge exchange. This technique is under study experimentally for use in a plasma jet propulsion unit and as an IEC type neutron source. Current work has studied the effect of locating the IEC grids off-center in the vacuum chamber, near the plasma entrance from the Helicon. With double grids, the relative potentials employed are also key factors in device performance. Electron emitters are added for space charge neutralization in the case of plasma jet propulsion. Plasma simulations are used to supplement the experiments. Specifically, the electric field and the magnetic field effects on energetic ion trajectories are examined for varying configurations. Funding by NASA, Air Force Research Lab and NPL Associates.

  17. Deuterium--tritium plasmas in novel regimes in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bell, M.G.; Batha, S.; Beer, M.; Bell, R.E.; Belov, A.; Berk, H.; Bernabei, S.; Bitter, M.; Breizman, B.; Bretz, N.L.; Budny, R.; Bush, C.E.; Callen, J.; Cauffman, S.; Chang, C.S.; Chang, Z.; Cheng, C.Z.; Darrow, D.S.; Dendy, R.O.; Dorland, W.; Duong, H.; Efthimion, P.C.; Ernst, D.; Evenson, H.; Fisch, N.J.; Fisher, R.; Fonck, R.J.; Fredrickson, E.D.; Fu, G.Y.; Furth, H.P.; Gorelenkov, N.N.; Goloborodko, V.Y.; Grek, B.; Grisham, L.R.; Hammett, G.W.; Hawryluk, R.J.; Heidbrink, W.; Herrmann, H.W.; Herrmann, M.C.; Hill, K.W.; Hogan, J.; Hooper, B.; Hosea, J.C.; Houlberg, W.A.; Hughes, M.; Jassby, D.L.; Jobes, F.C.; Johnson, D.W.; Kaita, R.; Kaye, S.; Kesner, J.; Kim, J.S.; Kissick, M.; Krasilnikov, A.V.; Kugel, H.; Kumar, A.; Lam, N.T.; Lamarche, P.; LeBlanc, B.; Levinton, F.M.; Ludescher, C.; Machuzak, J.; Majeski, R.P.; Manickam, J.; Mansfield, D.K.; Mauel, M.; Mazzucato, E.; McChesney, J.; McCune, D.C.; McKee, G.; McGuire, K.M.; Meade, D.M.; Medley, S.S.; Mikkelsen, D.R.; Mirnov, S.V.; Mueller, D.; Nagayama, Y.; Navratil, G.A.; Nazikian, R.; Okabayashi, M.; Osakabe, M.; Owens, D.K.; Park, H.K.; Park, W.; Paul, S.F.; Petrov, M.P.; Phillips, C.K.; Phillips, M.; Phillips, P.; Ramsey, A.T.; Rice, B.; Redi, M.H.; Rewoldt, G.; Reznik, S.; Roquemore, A.L.; Rogers, J.; Ruskov, E.; Sabbagh, S.A.; Sasao, M.; Schilling, G.; Schmidt, G.L.; Scott, S.D.; Semenov, I.; Senko, T.; Skinner, C.H.; Stevenson, T.; Strait, E.J.; Stratton, B.C.; Strachan, J.D.; Stodiek, W.; Synakowski, E.; Takahashi, H.; Tang, W.; Taylor, G.; Thompson, M.E.; von Goeler, S.; Von Halle, A.; Walters, R.T.; Wang, S.; White, R.; Wieland, R.M.; Williams, M.; Wilson, J.R.; Wong, K.L.; Wurden, G.A.; Yamada, M.; Yavorski, V.; Young, K.M.; Zakharov, L.; Zarnstorff, M.C.; Zweben, S.J. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    1997-05-01

    Experiments in the Tokamak Fusion Test Reactor (TFTR) [Phys. Plasmas {bold 2}, 2176 (1995)] have explored several novel regimes of improved tokamak confinement in deuterium{endash}tritium (D--T) plasmas, including plasmas with reduced or reversed magnetic shear in the core and high-current plasmas with increased shear in the outer region (high l{sub i}). New techniques have also been developed to enhance the confinement in these regimes by modifying the plasma-limiter interaction through {ital in situ} deposition of lithium. In reversed-shear plasmas, transitions to enhanced confinement have been observed at plasma currents up to 2.2 MA (q{sub a}{approx}4.3), accompanied by the formation of internal transport barriers, where large radial gradients develop in the temperature and density profiles. Experiments have been performed to elucidate the mechanism of the barrier formation and its relationship with the magnetic configuration and with the heating characteristics. The increased stability of high-current, high-l{sub i} plasmas produced by rapid expansion of the minor cross section, coupled with improvement in the confinement by lithium deposition has enabled the achievement of high fusion power, up to 8.7 MW, with D--T neutral beam heating. The physics of fusion alpha-particle confinement has been investigated in these regimes, including the interactions of the alphas with endogenous plasma instabilities and externally applied waves in the ion cyclotron range of frequencies. In D--T plasmas with q{sub 0}{gt}1 and weak magnetic shear in the central region, a toroidal Alfvn eigenmode instability driven purely by the alpha particles has been observed for the first time. The interactions of energetic ions with ion Bernstein waves produced by mode conversion from fast waves in mixed-species plasmas have been studied as a possible mechanism for transferring the energy of the alphas to fuel ions. {copyright} {ital 1997 American Institute of Physics.}

  18. Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Bindslev, Henrik;

    2011-01-01

    ratio. Measurements of the fuel ion ratio will be important for plasma control and machine protection in future experiments with burning fusion plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to plasma composition is enhanced......For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio—i.e. the tritium to deuterium density...... by the signatures of ion cyclotron motion and ion Bernstein waves which appear for scattering geometries with resolved wave vectors near perpendicular to the magnetic field. We investigate the origin and properties of these features in CTS spectra and give estimates of their relative importance for fuel ion ratio...

  19. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

    1986-08-29

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented.

  20. Formation of Plasmoid Chains in Fusion Relevant Plasmas

    CERN Document Server

    Comisso, Luca; Waelbroeck, François L

    2014-01-01

    The formation of plasmoid chains is explored for the first time within the context of the Taylor problem, in which magnetic reconnection is driven by a small amplitude boundary perturbation in a tearing-stable slab plasma equilibrium. Numerical simulations of a magnetohydrodynamical model of the plasma show that for very small plasma resistivity and viscosity, the linear inertial phase is followed by a nonlinear Sweet-Parker evolution, which gives way to a faster reconnection regime characterized by a chain of plasmoids instead of a slower Rutherford phase.

  1. The Science and Technology Challenges of the Plasma-Material Interface for Magnetic Fusion Energy

    Science.gov (United States)

    Whyte, Dennis

    2013-09-01

    The boundary plasma and plasma-material interactions of magnetic fusion devices are reviewed. The boundary of magnetic confinement devices, from the high-temperature, collisionless pedestal through to the surrounding surfaces and the nearby cold high-density collisional plasmas, encompasses an enormous range of plasma and material physics, and their integrated coupling. Due to fundamental limits of material response the boundary will largely define the viability of future large MFE experiments (ITER) and reactors (e.g. ARIES designs). The fusion community faces an enormous knowledge deficit in stepping from present devices, and even ITER, towards fusion devices typical of that required for efficient energy production. This deficit will be bridged by improving our fundamental science understanding of this complex interface region. The research activities and gaps are reviewed and organized to three major axes of challenges: power density, plasma duration, and material temperature. The boundary can also be considered a multi-scale system of coupled plasma and material science regulated through the non-linear interface of the sheath. Measurement, theory and modeling across these scales are reviewed, with a particular emphasis on establishing the use dimensionless parameters to understand this complex system. Proposed technology and science innovations towards solving the PMI/boundary challenges will be examined. Supported by US DOE award DE-SC00-02060 and cooperative agreement DE-FC02-99ER54512.

  2. Multi-scale physics mechanisms and spontaneous edge transport bifurcations in fusion plasmas

    Science.gov (United States)

    Hidalgo, C.; Pedrosa, M. A.; Silva, C.; Carralero, D.; Ascasibar, E.; Carreras, B. A.; Estrada, T.; Tabarés, F.; Tafalla, D.; Guasp, J.; Liniers, M.; López-Fraguas, A.; van Milligen, B.; Ochando, M. A.

    2009-09-01

    The magnitude of radial transport in magnetic confinement devices for controlled nuclear fusion suffers spontaneous bifurcations when specific system parameter values are exceeded. Here we show, for the first time, that the correlation length of the plasma potential becomes of the order of the machine size during the edge bifurcation itself, quite unlike the density fluctuations. The mechanism governing the development of this bifurcation, leading to the establishment of an edge transport barrier, is still one of the main scientific conundrums facing the magnetic fusion community after more than twenty years of intense research. The results presented here show the dominant role of long-range correlations when approaching the Low to High confinement edge transition in fusion plasmas. This is in line with the expectation that multi-scale interactions are a crucial ingredient of complex dynamics in many non-equilibrium systems.

  3. Deuterium-tritium plasmas in novel regimes in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bell, M.G.; Beer, M. [Princeton Univ., NJ (United States). Princeton Plasma Physics Lab.; Batha, S. [Fusion Physics and Technology, Torrance, CA (United States)] [and others

    1997-02-01

    Experiments in the Tokamak Fusion Test Reactor (TFTR) have explored several novel regimes of improved tokamak confinement in deuterium-tritium (D-T) plasmas, including plasmas with reduced or reversed magnetic shear in the core and high-current plasmas with increased shear in the outer region (high-l{sub i}). New techniques have also been developed to enhance the confinement in these regimes by modifying the plasma-limiter interaction through in-situ deposition of lithium. In reversed-shear plasmas, transitions to enhanced confinement have been observed at plasma currents up to 2.2 MA (q{sub a} {approx} 4.3), accompanied by the formation of internal transport barriers, where large radial gradients develop in the temperature and density profiles. Experiments have been performed to elucidate the mechanism of the barrier formation and its relationship with the magnetic configuration and with the heating characteristics. The increased stability of high-current, high-l{sub i} plasmas produced by rapid expansion of the minor cross-section, coupled with improvement in the confinement by lithium deposition has enabled the achievement of high fusion power, up to 8.7 MW, with D-T neutral beam heating. The physics of fusion alpha-particle confinement has been investigated in these regimes, including the interactions of the alphas with endogenous plasma instabilities and externally applied waves in the ion cyclotron range of frequencies. In D-T plasmas with q{sub 0} > 1 and weak magnetic shear in the central region, a toroidal Alfven eigenmode instability driven purely by the alpha particles has been observed for the first time. The interactions of energetic ions with ion Bernstein waves produced by mode-conversion from fast waves in mixed-species plasmas have been studied as a possible mechanism for transferring the energy of the alphas to fuel ions.

  4. Inertially confined fusion plasmas dominated by alpha-particle self-heating

    Science.gov (United States)

    Hurricane, O. A.; Callahan, D. A.; Casey, D. T.; Dewald, E. L.; Dittrich, T. R.; Döppner, T.; Haan, S.; Hinkel, D. E.; Berzak Hopkins, L. F.; Jones, O.; Kritcher, A. L.; Le Pape, S.; Ma, T.; Macphee, A. G.; Milovich, J. L.; Moody, J.; Pak, A.; Park, H.-S.; Patel, P. K.; Ralph, J. E.; Robey, H. F.; Ross, J. S.; Salmonson, J. D.; Spears, B. K.; Springer, P. T.; Tommasini, R.; Albert, F.; Benedetti, L. R.; Bionta, R.; Bond, E.; Bradley, D. K.; Caggiano, J.; Celliers, P. M.; Cerjan, C.; Church, J. A.; Dylla-Spears, R.; Edgell, D.; Edwards, M. J.; Fittinghoff, D.; Barrios Garcia, M. A.; Hamza, A.; Hatarik, R.; Herrmann, H.; Hohenberger, M.; Hoover, D.; Kline, J. L.; Kyrala, G.; Kozioziemski, B.; Grim, G.; Field, J. E.; Frenje, J.; Izumi, N.; Gatu Johnson, M.; Khan, S. F.; Knauer, J.; Kohut, T.; Landen, O.; Merrill, F.; Michel, P.; Moore, A.; Nagel, S. R.; Nikroo, A.; Parham, T.; Rygg, R. R.; Sayre, D.; Schneider, M.; Shaughnessy, D.; Strozzi, D.; Town, R. P. J.; Turnbull, D.; Volegov, P.; Wan, A.; Widmann, K.; Wilde, C.; Yeamans, C.

    2016-08-01

    Alpha-particle self-heating, the process of deuterium-tritium fusion reaction products depositing their kinetic energy locally within a fusion reaction region and thus increasing the temperature in the reacting region, is essential for achieving ignition in a fusion system. Here, we report new inertial confinement fusion experiments where the alpha-particle heating of the plasma is dominant with the fusion yield produced exceeding the fusion yield from the work done on the fuel (pressure times volume change) by a factor of two or more. These experiments have achieved the highest yield (26 +/- 0.5 kJ) and stagnation pressures (≍220 +/- 40 Gbar) of any facility-based inertial confinement fusion experiments, although they are still short of the pressures required for ignition on the National Ignition Facility (~300-400 Gbar). These experiments put us in a new part of parameter space that has not been extensively studied so far because it lies between the no-alpha-particle-deposition regime and ignition.

  5. Preface to Special Topic: Advances in Radio Frequency Physics in Fusion Plasmas

    Science.gov (United States)

    Tuccillo, Angelo A.; Phillips, Cynthia K.; Ceccuzzi, Silvio

    2014-06-01

    It has long been recognized that auxiliary plasma heating will be required to achieve the high temperature, high density conditions within a magnetically confined plasma in which a fusion "burn" may be sustained by copious fusion reactions. Consequently, the application of radio and microwave frequency electromagnetic waves to magnetically confined plasma, commonly referred to as RF, has been a major part of the program almost since its inception in the 1950s. These RF waves provide heating, current drive, plasma profile control, and Magnetohydrodynamics (MHD) stabilization. Fusion experiments employ electromagnetic radiation in a wide range of frequencies, from tens of MHz to hundreds of GHz. The fusion devices containing the plasma are typically tori, axisymmetric or non, in which the equilibrium magnetic fields are composed of a strong toroidal magnetic field generated by external coils, and a poloidal field created, at least in the symmetric configurations, by currents flowing in the plasma. The waves are excited in the peripheral regions of the plasma, by specially designed launching structures, and subsequently propagate into the core regions, where resonant wave-plasma interactions produce localized heating or other modification of the local equilibrium profiles. Experimental studies coupled with the development of theoretical models and advanced simulation codes over the past 40+ years have led to an unprecedented understanding of the physics of RF heating and current drive in the core of magnetic fusion devices. Nevertheless, there are serious gaps in our knowledge base that continue to have a negative impact on the success of ongoing experiments and that must be resolved as the program progresses to the next generation devices and ultimately to "demo" and "fusion power plant." A serious gap, at least in the ion cyclotron (IC) range of frequencies and partially in the lower hybrid frequency ranges, is the difficulty in coupling large amount of power to the

  6. Design of octahedral spherical hohlraum for CH Rev5 ignition capsule

    Science.gov (United States)

    Cao, Hui; Chen, Yao-Hua; Zhai, Chuanlei; Zheng, Chunyang; Lan, Ke

    2017-08-01

    In this paper, we design an octahedral spherical Au hohlraum for CH Rev5 ignition capsule [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)] by using the initial design method and two-dimensional (2D) simulations, and we investigate its laser entrance hole (LEH) closure and laser-plasma instabilities (LPI) by using a spherical hohlraum with two different-size LEHs via 2D simulations. The designed spherical hohlraum with RH=5 RC, RL=1.2 mm , and RL*=2 RL requires an ignition laser pulse of 1.92 MJ in energy and 670 TW in peak power, where RH, RC, RL, and RL* are radii of the spherical hohlraum, capsule, LEH, and the cylindrical LEH outer ring, respectively. From 2D simulations, the closure and opening up of LEH are clearly obtained. The LEH closure and its rate are strongly connected to the radiation pulse, while the LEH opening-up and its rate are strongly connected to the laser pulse. The smallest radius of LEH during closure is 0.6 mm before opening up, which leaves enough room for arranging the laser beams with a radius of 0.5 mm in our design. By using a post-process code for LPI, a relatively high stimulated Brillouin scattering fraction and a very low stimulated Raman scattering fraction are predicted, which may be due to the neglection of three-dimensional density gradients of the ablative flow along the laser transportation in 2D simulations. This work provides the energy and power references for the future ignition laser facility which uses octahedral spherical hohlraums as ignition targets.

  7. Review of Burning Plasma Physics. Fusion Energy Sciences Advisory Committee (FESAC)

    Energy Technology Data Exchange (ETDEWEB)

    Berk, Herb [Univ. of Texas, Austin, TX (United States); Betti, Riccardo [Univ. of Rochester, NY (United States); Dahlburg, Jill [Univ. of Georgia, Athens, GA (United States); Freidberg, Jeff [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Hopper, Bick [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Meade, Dale [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Navritil, Jerry [Columbia Univ., New York, NY (United States); Nevins, Bill [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ono, Masa [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Perkins, Rip [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Prager, Stewart [Univ. of Wisconsin, Madison, WI (United States); Schoenburg, Kurt [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taylor, Tony [Univ. of Georgia, Athens, GA (United States); Uckan, Nermin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2001-09-01

    The next frontier in the quest for magnetic fusion energy is the development of a basic understanding of plasma behavior in the regime of strong self-heating, the so called “burning plasma” regime. The general consensus in the fusion community is that the exploration of this frontier requires a new, relatively large experimental facility - a burning plasma experiment. The motivation, justification, and steps required to build such a facility are the primary focus of our report. The specific goals of the report are as follows. First, the report describes the critical scientific and engineering phenomena that are expected to arise for the first time, or else in a strongly modified form, in a burning plasma. Second, the report shows that the capabilities of existing experiments are inadequate to investigate these phenomena, thereby providing a major justification for a new facility. Third, the report compares the features and predicted performance of the three major next generation burning plasma experiments under current consideration (ITER-FEAT, FIRE, and IGNITOR), which are aimed at addressing these problems. Deliberately, no selection of the best option is made or attempted since such a decision involves complex scientific and cost issues that are beyond the scope of the present panel report. Fourth, the report makes specific recommendations regarding a process to move the burning plasma program forward, including a procedure for choosing the best option and the future activities of the Next Step Option (NSO) program. Fifth, the report attempts to provide a proper perspective for the role of burning plasmas with respect to the overall U.S. fusion program. The introduction provides the basic background information required for understanding the context in which the U.S. fusion community thinks about burning plasma issues. It “sets the stage” for the remainder of the report.

  8. CONFERENCE DESCRIPTION Theory of Fusion Plasmas: Varenna-Lausanne International Workshop

    Science.gov (United States)

    Garbet, X.; Sauter, O.

    2010-12-01

    The Joint Varenna-Lausanne international workshop on Theory of Fusion Plasmas takes place every other year in a place particularly favourable for informal and in-depth discussions. Invited and contributed papers present state-of-the-art research in theoretical plasma physics, covering all domains relevant to fusion plasmas. This workshop always welcomes a fruitful mix of experienced researchers and students, to allow a better understanding of the key theoretical physics models and applications. Theoretical issues related to burning plasmas Anomalous Transport (Turbulence, Coherent Structures, Microinstabilities) RF Heating and Current Drive Macroinstabilities Plasma-Edge Physics and Divertors Fast particles instabilities Further details: http://Varenna-Lausanne.epfl.ch The conference is organized by: Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Association EURATOM - Confédération Suisse 'Piero Caldirola' International Centre for the Promotion of Science and International School of Plasma Physics Istituto di Fisica del Plasma del CNR, Milano Editors: X Garbet (CEA, Cadarache, France) and O Sauter (CRPP-EPFL, Lausanne, Switzerland)

  9. Explosive-Driven Hemispherical Implosions for Generating Fusion Plasmas

    Science.gov (United States)

    1982-03-01

    thermal speed. In "inertial fusion" (3) the reaction confinement is essentially at the sound speed or thermal disassembly time (3 x 10- 1 1 sec at T...block the ~ eutron path to the scintillator. The expected performance is listed in Table 2.2. Most of the suggested approaches are based on activat- ion...by the fast neutrons, while the activation cross-section for fast neutrons is considerably lower than that of thermal neutrons. We have found it more

  10. Fusion burning waves in proton-boron-11 plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Val, J.M. [Universidad Poltecnica de Madrid (Spain). Inst. de Fusion Nuclear; Eliezer, S. [Universidad Poltecnica de Madrid (Spain). Inst. de Fusion Nuclear; Piera, M. [Universidad Poltecnica de Madrid (Spain). Inst. de Fusion Nuclear; Velarde, G. [Universidad Poltecnica de Madrid (Spain). Inst. de Fusion Nuclear

    1996-06-17

    A method is proposed to exploit the aneutronic proton-{sup 11}B fusion reaction by means of igniting a heat detonation wave that expands across the fuel from a small heated region. The ignition process is triggered by a particle beam (or a couple of beams) impinging on an inertially compressed target. We determine conditions for ignition and burn propagation. Although the requirements on the igniting beam current are very high, the method is a clear hint how to produce the cleanest energy from nuclear reactions. (orig.).

  11. Mitigating the impact of hohlraum asymmetries in National Ignition Facility implosions using capsule shims

    Science.gov (United States)

    Clark, D. S.; Weber, C. R.; Smalyuk, V. A.; Robey, H. F.; Kritcher, A. L.; Milovich, J. L.; Salmonson, J. D.

    2016-07-01

    Current indirect drive implosion experiments on the National Ignition Facility (NIF) [Moses et al., Phys. Plasmas 16, 041006 (2009)] are believed to be strongly impacted by long wavelength perturbations driven by asymmetries in the hohlraum x-ray flux. To address this perturbation source, active efforts are underway to develop modified hohlraum designs with reduced asymmetry imprint. An alternative strategy, however, is to modify the capsule design to be more resilient to a given amount of hohlraum asymmetry. In particular, the capsule may be deliberately misshaped, or "shimmed," so as to counteract the expected asymmetries from the hohlraum. Here, the efficacy of capsule shimming to correct the asymmetries in two recent NIF implosion experiments is assessed using two-dimensional radiation hydrodynamics simulations. Despite the highly time-dependent character of the asymmetries and the high convergence ratios of these implosions, simulations suggest that shims could be highly effective at counteracting current asymmetries and result in factors of a few enhancements in neutron yields. For higher compression designs, the yield improvement could be even greater.

  12. Multi-keV X-ray sources from metal-lined cylindrical hohlraums

    Directory of Open Access Journals (Sweden)

    Jacquet L.

    2013-11-01

    Full Text Available In 2009 a series of metal-lined hohlraums were tested on the Omega laser facility. The main aims of the campaign were to improve our understanding of the multi-keV energy production and our capability to numerically reproduce the measured conversion efficiencies (CE's. Two studies have been primarily planned: the effect of the metallic plasma mean ionization states and that of hydrodynamics. Six targets were experimented for which the metallic materials (titanium, copper, germanium, the cavity diameter, and the irradiation energy were varied. Here we compare experimental and calculated results. The numerical simulations are performed with the 2D hydro-radiative code FCI2. For all the cavities, the measured multi-keV x-ray powers versus time are qualitatively well reproduced by the simulations, indicating that hohlraum hydrodynamics seems to be well calculated. But we have an underestimation by a factor of ∼2 for the calculated CEs versus experimental values for titanium and copper hohlraums. By contrast there is a good agreement between measurements and calculations for the germanium hohlraum. To explain these results, we have calculated off-line integrated emissivities for couples of (ρ, Te values contributing to the multi-keV production with several non-local-thermal-equilibrium (NLTE atomic physics models.

  13. New compact hohlraum configuration research at the 1.7 MA Z-pinch generator

    Energy Technology Data Exchange (ETDEWEB)

    Kantsyrev, V. L., E-mail: victor@unr.edu; Shrestha, I. K.; Esaulov, A. A.; Safronova, A. S.; Shlyaptseva, V. V.; Osborne, G. C.; Astanovitsky, A. L.; Weller, M. E.; Stafford, A.; Schultz, K. A.; Cooper, M. C. [Physics Department, University of Nevada, Reno, NV 89557 (United States); Chuvatin, A. S. [Laboratorie de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau (France); Rudakov, L. I. [Icarus Research Inc., P.O. Box 30780, Bethesda, MD 20824-0780 (United States); Velikovich, A. L. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Cuneo, M. E.; Jones, B.; Vesey, R. A. [Sandia National Laboratories, Albuquerque, NM 87110 (United States)

    2014-12-15

    A new compact Z-pinch x-ray hohlraum design with parallel-driven x-ray sources was experimentally demonstrated in a full configuration with a central target and tailored shine shields (to provide a symmetric temperature distribution on the target) at the 1.7 MA Zebra generator. This presentation reports on the joint success of two independent lines of research. One of these was the development of new sources – planar wire arrays (PWAs). PWAs turned out to be a prolific radiator. Another success was the drastic improvement in energy efficiency of pulsed-power systems, such as the Load Current Multiplier (LCM). The Zebra/LCM generator almost doubled the plasma load current to 1.7 MA. The two above-mentioned innovative approaches were used in combination to produce a new compact hohlraum design for ICF, as jointly proposed by SNL and UNR. Good agreement between simulated and measured radiation temperature of the central target is shown. Experimental comparison of PWAs with planar foil liners (PFL) - another viable alternative to wire array loads at multi-MA generators show promising data. Results of research at the University of Nevada Reno allowed for the study of hohlraum coupling physics at University-scale generators. The advantages of new hohlraum design applications for multi-MA facilities with W or Au double PWAs or PFL x-ray sources are discussed.

  14. Pre-formed plasma channels for ion beam fusion

    Science.gov (United States)

    Peterson, R. R.; Olson, C. L.

    1997-04-01

    The transport of driver ions to the target in an IFE power plant is an important consideration in IFE target chamber design. Pre-formed laser-guided plasma discharge channels have been considered for light ions because they reduce the beam microdivergence constraints, allow long transport lengths, and require a target chamber fill gas that can help protect the target chamber from the target explosion. Here, pre-formed plasma discharge channels are considered for heavy ion transport. The channel formation parameters are similar to those for light ions. The allowable ion power per channel is limited by the onset of plasma instabilities and energy loss due to a reverse emf from the rapid channel expansion driven by the ion beam.

  15. Multi-fluid studies of plasma shocks relevant to inertial confinement fusion

    Science.gov (United States)

    Srinivasan, B.; Kagan, G.; Adams, C. S.

    2016-05-01

    Results from inertial confinement fusion (ICF) experiments performed at the Omega laser facility suggest the potential role of kinetic effects in plasmas during implosion. Recent theoretical and numerical work has indicated the importance of diffusion effects in the presence of multiple ion species as well as the importance of ion viscosity. This provides the motivation to adequately develop multi-fluid plasma models capable of capturing kinetic physics including concentration diffusion and ion species separation driven by the ion concentration gradient, the ion pressure gradient, the electron and ion temperature gradients, and the electric field. Benchmarks between the newly developed code and analytical results are presented for multi-fluid plasma shocks.

  16. K-alpha conversion efficiency measurments for x-ray scattering in inertial confinement fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kritcher, A L; Neumayer, P; Urry, M K; Robey, H; Niemann, C; Landen, O L; Morse, E; Glenzer, S H

    2006-11-21

    The conversion efficiency of ultra short-pulse laser radiation to K-{alpha} x-rays has been measured for various chlorine-containing targets to be used as x-ray scattering probes of dense plasmas. The spectral and temporal properties of these sources will allow spectrally-resolved x-ray scattering probing with picosecond temporal resolution required for measuring the plasma conditions in inertial confinement fusion experiments. Simulations of x-ray scattering spectra from these plasmas show that fuel capsule density, capsule ablator density, and shock timing information may be inferred.

  17. Semi-analytic model of plasma-jet-driven magneto-inertial fusion

    Science.gov (United States)

    Langendorf, Samuel J.; Hsu, Scott C.

    2017-03-01

    A semi-analytic model for plasma-jet-driven magneto-inertial fusion is presented. Compressions of a magnetized plasma target by a spherically imploding plasma liner are calculated in one dimension (1D), accounting for compressible hydrodynamics and ionization of the liner material, energy losses due to conduction and radiation, fusion burn and alpha deposition, separate ion and electron temperatures in the target, magnetic pressure, and fuel burn-up. Results show 1D gains of 3-30 at spherical convergence ratio energy, for cases in which the liner thickness is 1 cm and the initial radius of a preheated magnetized target is 4 cm. Some exploration of parameter space and physics settings is presented. The yields observed suggest that there is a possibility of igniting additional dense fuel layers to reach high gain.

  18. Diamond coatings exposure to fusion-relevant plasma conditions

    NARCIS (Netherlands)

    Porro, S.; De Temmerman, G.; Lisgo, S.; Rudakov, D. L.; Litnovsky, A.; Petersson, P.; John, P.; Wilson, J. I. B.

    2011-01-01

    Several types of diamond layers have been deposited on molybdenum tiles by chemical vapour deposition techniques, and exposed under erosion-dominated conditions in the SOL of TEXTOR in order to assess them as a suitable candidate for plasma-facing material. Post-exposure characterisation of physical

  19. An Electrothermal Plasma Source Developed for Simulation of Transient Heat Loads in Future Large Fusion Devices

    Science.gov (United States)

    Gebhart, Trey; Baylor, Larry; Winfrey, Leigh

    2016-10-01

    The realization of fusion energy requires materials that can withstand high heat and particle fluxes at the plasma material interface. In this work, an electrothermal (ET) plasma source has been designed as a possible transient heat flux source for a linear plasma material interaction device. An ET plasma source operates in the ablative arc regime, which is driven by a DC capacitive discharge. The current travels through the 4mm bore of a boron nitride liner and subsequently ablates and ionizes the liner material. This results in a high density plasma with a large unidirectional bulk flow out of the source exit. The pulse length for the ET source has been optimized using a pulse forming network to have a duration of 1ms at full-width half maximum. The peak currents and maximum source energies seen in this system are 2kA and 5kJ. The goal of this work is to show that the ET source produces electron densities and heat fluxes that are comparable to transient events in future large magnetic confinement fusion devices. Heat flux, plasma temperature, and plasma density were determined for each test shot using infrared imaging and optical spectroscopy techniques. This work will compare the ET source output (heat flux, temperature, and density) with and without an applied magnetic field. Research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy.

  20. New atomic data for Kr XXXV useful in fusion plasma

    Institute of Scientific and Technical Information of China (English)

    Sunny Aggarwal; Jagjit Singh; Man Mohan

    2013-01-01

    Energy levels and emission line wavelengths of high-Z materials are useful for impurity diagnostics due to their potential application in the next generation fusion devices.For this purpose,we have calculated the fine structural energies of the 67 levels belonging to the ls2,ls21,ls31,ls41,ls51,and ls61 configurations of Kr XXXV using GRASP (general purpose relativistic atomic structure package) code.Additionally,we have reported the transition probabilities,oscillator strengths,line strengths,and transition wavelengths for some electric dipole (El) transitions among these levels.We predict new energy levels and radiative rates,which have not been reported experimentally or theoretically,forming the basis for future experimental work.

  1. Laser surface fusion of plasma sprayed ceramic turbine seals

    Science.gov (United States)

    Wisander, D. W.; Bill, R. C. (Inventor)

    1981-01-01

    The thermal shock resistance of a ceramic layer is improved. An improved abradable lining that is deposited on a shroud forming a gas path seal in turbomachinery is emphasized. Improved thermal shock resistance of a shroud is effective through the deliberate introduction of 'benign' cracks. These are microcracks which will not propagate appreciably upon exposure to the thermal shock environment in which a turbine seal must function. Laser surface fusion treatment is used to introduce these microcracks. The ceramic surface is laser scanned to form a continuous dense layer. As this cools and solidifies, shrinkage results in the formation of a very fine crack network. The presence of this deliberately introduced fine crack network precludes the formation of a catastrophic crack during thermal shock exposure.

  2. An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas

    Science.gov (United States)

    De, B. R.; Srnka, L. J.

    1978-01-01

    Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.

  3. Simulation of transition dynamics to high confinement in fusion plasmas

    DEFF Research Database (Denmark)

    Nielsen, Anders Henry; Xu, G. S.; Madsen, Jens;

    2015-01-01

    The transition dynamics from the low (L) to the high (H) confinement mode in magnetically confined plasmas is investigated using a first-principles four-field fluid model. Numerical results are in agreement with measurements from the Experimental Advanced Superconducting Tokamak - EAST. Particula......The transition dynamics from the low (L) to the high (H) confinement mode in magnetically confined plasmas is investigated using a first-principles four-field fluid model. Numerical results are in agreement with measurements from the Experimental Advanced Superconducting Tokamak - EAST....... Particularly, the slow transition with an intermediate dithering phase is well reproduced at proper parameters. The model recovers the power threshold for the L-H transition as well as the decrease in power threshold switching from single to double null configuration observed experimentally. The results...

  4. Pulse compression radar reflectometry for density measurements on fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Costley, A.; Prentice, R. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Laviron, C. [Compagnie Generale des Matieres Nucleaires (COGEMA), 78 - Velizy-Villacoublay (France); Prentice, R. [Toulouse-3 Univ., 31 (France). Centre d`Etude Spatiale des Rayonnements

    1994-07-01

    On tokamaks and other toroidal machines, reflectometry is a very rapidly developing technique for density profile measurements, particularly near the edge. Its principle relies on the total reflection of an electromagnetic wave at a cutoff layer, where the critical density is reached and the local refractive index goes to zero. With the new fast frequency synthesizers now available, a method based on pulse compression radar is proposed for plasma reflectometry, overcoming the limitations of the previous reflectometry methods. The measurement can be made on a time-scale which is effectively very short relatively to the plasma fluctuations, and the very high reproducibility and stability of the source allows an absolute calibration of the waveguides to be made, which corrects for the effects of the parasitic reflections. 2 refs., 5 figs.

  5. Effect of impurities on kinetic transport processes in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Stefanie

    2010-12-10

    Within the framework of this thesis, different problems arising in connection with impurities have been investigated. Collisional damping of zonal flows in tokamaks: Since the Coulomb collision frequency increases with increasing ion charge, heavy, highly charged impurities play an important role in this process. The effect of such impurities on the linear response of the plasma to an external potential perturbation, as caused by zonal flows, is calculated with analytical methods. In comparison with a pure plasma, the damping of the flows occurs, as expected, considerably faster; for experimentally relevant parameters, the enhancement exceeds the effective charge Z{sub eff} of the plasma. Impurity transport driven by microturbulence in tokamaks: With regard to impurities, it is especially important whether the resulting flows are directed inwards or outwards, since they are deleterious for core energy confinement on the one hand, but on the other hand help protecting plasma-facing components from too high energy fluxes in the edge region. A semi-analytical model is presented describing the resulting impurity fluxes and the stability boundary of the underlying mode. The main goal is to bridge the gap between, on the one hand, costly numerical simulations, which are applicable to a broad range of problems but yield scarcely traceable results, and, on the other hand, analytical theory, which might ease the interpretation of the results but is so far rather rudimentary. The model is based on analytical formulae whenever possible but resorts to a numerical treatment when the approximations necessary for an analytical solution would lead to a substantial distortion of the results. Both the direction of the impurity flux and the stability boundary are found to depend sensitively on the plasma parameters such as the impurity density and the temperature gradient. Pfirsch-Schlueter transport in stellarators: Due to geometry effects, collisional transport plays a much more

  6. pF3D Simulations of SBS and SRS in NIF Hohlraum Experiments

    Science.gov (United States)

    Langer, Steven; Strozzi, David; Amendt, Peter; Chapman, Thomas; Hopkins, Laura; Kritcher, Andrea; Sepke, Scott

    2016-10-01

    We present simulations of stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) for NIF experiments using high foot pulses in cylindrical hohlraums and for low foot pulses in rugby-shaped hohlraums. We use pF3D, a massively-parallel, paraxial-envelope laser plasma interaction code, with plasma profiles obtained from the radiation-hydrodynamics codes Lasnex and HYDRA. We compare the simulations to experimental data for SBS and SRS power and spectrum. We also show simulated SRS and SBS intensities at the target chamber wall and report the fraction of the backscattered light that passes through and misses the lenses. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-697482.

  7. Plasma-material Interactions in Current Tokamaks and their Implications for Next-step Fusion Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Federici, G.; Skinner, C.H.; Brooks, J.N.; Coad, J.P.; Grisolia, C. [and others

    2001-01-10

    The major increase in discharge duration and plasma energy in a next-step DT [deuterium-tritium] fusion reactor will give rise to important plasma-material effects that will critically influence its operation, safety, and performance. Erosion will increase to a scale of several centimeters from being barely measurable at a micron scale in today's tokamaks. Tritium co-deposited with carbon will strongly affect the operation of machines with carbon plasma-facing components. Controlling plasma wall interactions is critical to achieving high performance in present-day tokamaks and this is likely to continue to be the case in the approach to practical fusion reactors. Recognition of the important consequences of these phenomena has stimulated an internationally coordinated effort in the field of plasma-surface interactions supporting the Engineering Design Activities of the International Thermonuclear Experimental Reactor (ITER) project and significant progress has been made in better under standing these issues. This paper reviews the underlying physical processes and the existing experimental database of plasma-material interactions both in tokamaks and laboratory simulation facilities for conditions of direct relevance to next-step fusion reactors. Two main topical groups of interactions are considered: (i) erosion/redeposition from plasma sputtering and disruptions, including dust and flake generation, (ii) tritium retention and removal. The use of modeling tools to interpret the experimental results and make projections for conditions expected in future devices is explained. Outstanding technical issues and specific recommendations on potential R and D [Research and Development] avenues for their resolution are presented.

  8. Fusion

    Science.gov (United States)

    Herman, Robin

    1990-10-01

    The book abounds with fascinating anecdotes about fusion's rocky path: the spurious claim by Argentine dictator Juan Peron in 1951 that his country had built a working fusion reactor, the rush by the United States to drop secrecy and publicize its fusion work as a propaganda offensive after the Russian success with Sputnik; the fortune Penthouse magazine publisher Bob Guccione sank into an unconventional fusion device, the skepticism that met an assertion by two University of Utah chemists in 1989 that they had created "cold fusion" in a bottle. Aimed at a general audience, the book describes the scientific basis of controlled fusion--the fusing of atomic nuclei, under conditions hotter than the sun, to release energy. Using personal recollections of scientists involved, it traces the history of this little-known international race that began during the Cold War in secret laboratories in the United States, Great Britain and the Soviet Union, and evolved into an astonishingly open collaboration between East and West.

  9. Interaction between sheared flows and turbulent transport in magnetized fusion-grade plasmas; Interaction entre ecoulements cisailles et transport turbulent dans les plasmas de fusion magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Leconte, M.

    2008-11-15

    The H confinement regime is set when the heating power reaches a threshold value P{sub c} and is linked to the formation of a transport barrier in the edge region of the plasma. Such a barrier is characterized by a high pressure gradient and is submitted to ELM (edge localized mode) instabilities. ELM instabilities trigger violent quasi-periodical ejections of matter and heat that induce quasi-periodical relaxations of the transport barrier called relaxation oscillations. In this work we studied the interaction between sheared flows and turbulence in fusion plasmas. In particular, we studied the complex dynamics of a transport barrier and we show through a simulation that resonant magnetic perturbations could control relaxation oscillations without a significant loss of confinement

  10. A unified model of density limit in fusion plasmas

    CERN Document Server

    Zanca, P; Escande, D F; Pucella, G; Tudisco, O

    2016-01-01

    A limit for the edge density, ruled by radiation losses from light impurities, is established by a minimal cylindrical magneto-thermal equilibrium model. For ohmic tokamak and reversed field pinch the limit scales linearly with the plasma current, as the empirical Greenwald limit. The auxiliary heating adds a further dependence, scaling with the 0.4 power, in agreement with L-mode tokamak experiments. For a purely externally heated configuration the limit takes on a Sudo-like form, depending mainly on the input power, and is compatible with recent Stellarator scalings.

  11. Upgrade of the IGN-14 neutron generator for research on detection of fusion-plasma products

    Energy Technology Data Exchange (ETDEWEB)

    Igielski, Andrzej; Kurowski, Arkadiusz; Janik, Władysław; Gabańska, Barbara; Woźnicka, Urszula, E-mail: Urszula.Woznicka@ifj.edu.pl

    2015-10-11

    The fast neutron generator (IGN-14) at the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Kraków (Poland) is a laboratory multi-purpose experimental device. Neutrons are produced in a beam-target D–D or D–T reactions. A new vacuum chamber installed directly to the end of the ion guide of IGN-14 makes it possible to measure not only neutrons but also alpha particles in the presence of a mixed radiation field of other accompanying reaction products. The new experimental setup allows test detectors dedicated to spectrometric measurements of thermonuclear fusion reaction products. - Highlights: • Nuclear reactions at the target correspond to the fusion reaction in hot plasma. • Measuring vacuum chamber has been built and installed. • Spatial distribution of the particle mixed fields in chamber was calculated. • New experimental setup for tests of detectors dedicated to measure of fusion reaction products.

  12. Fokker Planck kinetic modeling of suprathermal alpha-particles in a fusion plasma

    CERN Document Server

    Peigney, Benjamin-Edouard; Tikhonchuk, Vladimir

    2014-01-01

    We present an ion kinetic model describing the ignition and burn of the deuterium-tritium fuel of inertial fusion targets. The analysis of the underlying physical model enables us to develop efficient numerical methods to simulate the creation, transport and collisional relaxation of fusion reaction products (alpha-particles) at a kinetic level. A two-energy-scale approach leads to a self-consistent modeling of the coupling between suprathermal alpha-particles and the thermal bulk of the imploding plasma. This method provides an accurate numerical treatment of energy deposition and transport processes involving suprathermal particles. The numerical tools presented here are validated against known analytical results. This enables us to investigate the potential role of ion kinetic effects on the physics of ignition and thermonuclear burn in inertial confinement fusion schemes.

  13. A unified model of density limit in fusion plasmas

    Science.gov (United States)

    Zanca, P.; Sattin, F.; Escande, D. F.; Pucella, G.; Tudisco, O.

    2017-05-01

    In this work we identify by analytical and numerical means the conditions for the existence of a magnetic and thermal equilibrium of a cylindrical plasma, in the presence of Ohmic and/or additional power sources, heat conduction and radiation losses by light impurities. The boundary defining the solutions’ space having realistic temperature profile with small edge value takes mathematically the form of a density limit (DL). Compared to previous similar analyses the present work benefits from dealing with a more accurate set of equations. This refinement is elementary, but decisive, since it discloses a tenuous dependence of the DL on the thermal transport for configurations with an applied electric field. Thanks to this property, the DL scaling law is recovered almost identical for two largely different devices such as the ohmic tokamak and the reversed field pinch. In particular, they have in common a Greenwald scaling, linearly depending on the plasma current, quantitatively consistent with experimental results. In the tokamak case the DL dependence on any additional heating approximately follows a 0.5 power law, which is compatible with L-mode experiments. For a purely externally heated configuration, taken as a cylindrical approximation of the stellarator, the DL dependence on transport is found stronger. By adopting suitable transport models, DL takes on a Sudo-like form, in fair agreement with LHD experiments. Overall, the model provides a good zeroth-order quantitative description of the DL, applicable to widely different configurations.

  14. Plasma-Jet-Driven Magneto-Inertial Fusion (PJMIF): Physics and Design for a Plasma Liner Formation Experiment

    Science.gov (United States)

    Hsu, Scott; Cassibry, Jason; Witherspoon, F. Douglas

    2014-10-01

    Spherically imploding plasma liners are a potential standoff compression driver for magneto-inertial fusion, which is a hybrid of and operates in an intermediate density between those of magnetic and inertial fusion. We propose to use an array of merging supersonic plasma jets to form a spherically imploding plasma liner. The jets are to be formed by pulsed coaxial guns with contoured electrodes that are placed sufficiently far from the location of target compression such that no hardware is repetitively destroyed. As such, the repetition rate can be higher (e.g., 1 Hz) and ultimately the power-plant economics can be more attractive than most other MIF approaches. During the R&D phase, a high experimental shot rate at reasonably low cost (e.g., gun plasma-liner-formation experiment, which will provide experimental data on: (i) scaling of peak liner ram pressure versus initial jet parameters, (ii) liner non-uniformity characterization and control, and (iii) control of liner profiles for eventual gain optimization.

  15. The application of quasi-steady approximation in atomic kinetics in simulation of hohlraum radiation drive

    Science.gov (United States)

    Ren, Guoli; Pei, Wenbing; Lan, Ke; Li, Xin; Hohlraum Physics Team

    2014-10-01

    In current routine 2D simulation of hohlraum physics, we adopt the principal-quantum-number (n-level) average atom model (AAM) in NLTE plasma description. The more sophisticated atomic kinetics description is better choice, but the in-line calculation consumes much more resource. By distinguishing the much more fast bound-bound atomic processes from the relative slow bound-free atomic processes, we found a method to built up a bound electron distribution (n-level or nl-level) using in-line n-level calculated plasma condition (such as temperature, density, average ionization degree). We name this method ``quasi-steady approximation.'' Using this method and the plasma condition calculated under n-level, we re-build the nl-level bound electron distribution (Pnl), and acquire a new hohlraum radiative drive by post-processing. Comparison with the n-level post-processed hohlraum drive shows that we get an almost identical radiation flux but with more-detailed frequency-dependant structures. Also we use this method in the benchmark gold sphere experiment, the constructed nl-level radiation drive resembles the experimental results and DCA results, while the n-level raditation does not.

  16. Laser-Driven Ultra-Relativistic Plasmas - Nuclear Fusion in Coulomb Shock Waves, Rouge Waves, and Background Matter

    Science.gov (United States)

    2015-05-05

    AND SUBTITLE LASER-DRIVEN ULTRA-RELATIVISTIC PLASMAS - NUCLEAR FUSION IN COULOMB SHOCK WAVES, ROUGE WAVES, AND BACKGROUND MATTER. 5a.  CONTRACT...blackbody radiation on free electrons .........................9 2.vi. Proposal of ultimate test of laser nuclear fusion efficiency in clusters...domain of energies and temperatures, with applications in particular to controlled nuclear fusion . 2. Final technical report on the grant #F49620-11-1

  17. Recent Progress on Atomic Data for Fusion Plasma in KAERI Nuclear Data Center

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Duckhee; Hwang, In Hyuk; Rhee, Yongjoo; Lee, Youngouk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Atomic structure and collision cross sections are essential data for spectroscopic diagnostics of fusion plasma. We have carried out state-of-the-art calculations on cross sections for electron-impact ionization (EII) cross sections of various atoms and ions. Here we report our recent progress on those calculations and discuss future research plan focusing on the actual need for fusion plasma diagnostics. We have calculated EII cross sections of P-like ions including Fe{sup 11+}, and W ions based on a DWA. Present calculations agree with experiments better than previous other calculations. However, for lowly charged ions, our DWA calculations which uses approximated, non unitary scattering matrix have sizable discrepancies with experiments. Hence unitary corrections would be required to improve EII calculations for lowly charged ions. As well more sophisticated R matrix calculations would be required for EII of those ions in order to test DWA calculations mutually.

  18. Developing a plasma focus research training system for the fusion energy age

    Science.gov (United States)

    Lee, S.

    2014-08-01

    The 3 kJ UNU/ICTP Plasma Focus Facility is the most significant device associated with the AAAPT (Asian African Association for Plasma Training). In original and modified/upgraded form it has trained generations of plasma focus (PF) researchers internationally, producing many PhD theses and peer-reviewed papers. The Lee Model code was developed for the design of this PF. This code has evolved to cover all PF machines for design, interpretation and optimization, for derivation of radiation scaling laws; and to provide insights into yield scaling limitations, radiative collapse, speed-enhanced and current-stepped PF variants. As example of fresh perspectives derivable from this code, this paper presents new results on energy transfers of the axial and radial phases of generalized PF devices. As the world moves inexorably towards the Fusion Energy Age it becomes ever more important to train plasma fusion researchers. A recent workshop in Nepal shows that demand for such training continues. Even commercial project development consultants are showing interest. We propose that the AAAPT-proven research package be upgraded, by modernizing the small PF for extreme modes of operation, switchable from the typical strong-focus mode to a slow-mode which barely pinches, thus producing a larger, more uniform plasma stream with superior deposition properties. Such a small device would be cost-effective and easily duplicated, and have the versatility of a range of experiments from intense multi-radiation generation and target damage studies to superior advanced-materials deposition. The complementary code is used to reference experiments up to the largest existing machine. This is ideal for studying machine limitations and scaling laws and to suggest new experiments. Such a modernized versatile PF machine complemented by the universally versatile code would extend the utility of the PF experience; so that AAAPT continues to provide leadership in pulsed plasma research training in

  19. The in-situ diagnosis of plasma-wall interactions on magnetic fusion devices with accelerators

    Science.gov (United States)

    Hartwig, Zachary

    2013-10-01

    We present the first in-situ, time-resolved measurements of low-Z isotope composition and deuterium retention over a large plasma-facing component (PFC) surface area in a magnetic fusion device. These critical measurements were made using a novel diagnostic technique based on the analysis of induced nuclear reactions from PFC surfaces on the Alcator C-Mod tokamak. Achieving an integrated understanding of plasma physics and materials science in magnetic fusion devices is severely hindered by a dearth of in-situ PFC surface diagnosis. Plasma-wall interactions, such as the erosion/redeposition of PFC material, the evolution of PFC surface isotope composition, and fusion fuel retention present significant plasma physics and materials science challenges for long pulse or steady-state devices. Our diagnostic uses a compact (~1 meter), high-current (~1 milliamp) radio-frequency quadrupole accelerator to inject ~1 MeV deuterons into the vacuum vessel. We control the tokamak's magnetic fields - in between plasma shots - to steer the deuterons to PFC surfaces, where they induce high-Q nuclear reactions with low-Z isotopes in the first ~10 microns of material. Analysis of the induced gamma and neutron energy spectra provides quantitative reconstruction of PFC surface conditions. This nondestructive, in-situ technique achieves PFC surface composition measurements with plasma shot-to-shot time resolution and 1 centimeter spatial resolution over large PFC areas. Work supported by U.S. DOE Grant DE-FG02-94ER54235 and Cooperative Agreement DE-FC02-99ER54512.

  20. Interplay between fast ions and turbulence in magnetic fusion plasmas

    Science.gov (United States)

    Dumont, R. J.; Zarzoso, D.; Sarazin, Y.; Garbet, X.; Strugarek, A.; Abiteboul, J.; Cartier-Michaud, T.; Dif-Pradalier, G.; Ghendrih, Ph; Girardo, J.-B.; Grandgirard, V.; Latu, G.; Passeron, C.; Thomine, O.

    2013-12-01

    Evidence for the impact of energetic particles (EPs) on turbulence is given in this paper. Firstly, the excitation of electrostatic instabilities in linear gyrokinetic simulations performed with the global GYSELA code by introducing distribution functions typical of fast ions in tokamak plasmas is presented. The obtained mode is unambiguously characterized as an EGAM, i.e. a geodesic acoustic mode (GAM) excited by EPs. The influence of EGAMs on turbulence and associated transport is then analyzed by implementing a source adapted to the inclusion of fast particle populations in non-linear simulations. This source successfully excites EGAMs in the presence of turbulence, which leads to a drastic reduction of the turbulent transport. However, this reduction is only transient; it is followed by an increase of the turbulent activity, characterized by a complex interaction between the EGAMs and the turbulence. In the subsequent steady-state regime, turbulent transport appears to be modulated at the EGAM frequency.

  1. Dust particles in controlled fusion devices: morphology, observations in the plasma and influence on the plasma performance

    Science.gov (United States)

    Rubel, M.; Cecconello, M.; Malmberg, J. A.; Sergienko, G.; Biel, W.; Drake, J. R.; Hedqvist, A.; Huber, A.; Philipps, V.

    2001-08-01

    The formation and release of particle agglomerates, i.e. debris and dusty objects, from plasma facing components and the impact of such materials on plasma operation in controlled fusion devices has been studied in the Extrap T2 reversed field pinch and the TEXTOR tokamak. Several plasma diagnostic techniques, camera observations and surface analysis methods were applied for in situ and ex situ investigation. The results are discussed in terms of processes that are decisive for dust transfer: localized power deposition connected with wall locked modes causing emission of carbon granules, brittle destruction of graphite and detachment of thick flaking co-deposited layers. The consequences for large next step devices are also addressed.

  2. Silicon Drift Detector for Soft x-ray Spectrometer in Fusion Plasmas

    Institute of Scientific and Technical Information of China (English)

    LI Mei; JU Hong-jun

    2008-01-01

    Silicon drift detector(SDD) is used in the soft x-ray pulse height analyzer(PHA) to measure soft x-ray emissions in fusion plasmas. SDD has the virtues of high count rates and high energy resolution, and the good performances at work temperature of about -10 ℃ achieved by single stage peltier element. The performance and first experimental results from SDD system are presented.

  3. Status Update: Modeling Energy Balance in NIF Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-22

    We have developed a standardized methodology to model hohlraum drive in NIF experiments. We compare simulation results to experiments by 1) comparing hohlraum xray fluxes and 2) comparing capsule metrics, such as bang times. Long-pulse, high gas-fill hohlraums require a 20-28% reduction in simulated drive and inclusion of ~15% backscatter to match experiment through (1) and (2). Short-pulse, low fill or near-vacuum hohlraums require a 10% reduction in simulated drive to match experiment through (2); no reduction through (1). Ongoing work focuses on physical model modifications to improve these matches.

  4. Status Update: Modeling Energy Balance in NIF Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-22

    We have developed a standardized methodology to model hohlraum drive in NIF experiments. We compare simulation results to experiments by 1) comparing hohlraum xray fluxes and 2) comparing capsule metrics, such as bang times. Long-pulse, high gas-fill hohlraums require a 20-28% reduction in simulated drive and inclusion of ~15% backscatter to match experiment through (1) and (2). Short-pulse, low fill or near-vacuum hohlraums require a 10% reduction in simulated drive to match experiment through (2); no reduction through (1). Ongoing work focuses on physical model modifications to improve these matches.

  5. Prospects for x-ray polarimetry measurements of magnetic fields in magnetized liner inertial fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Lynn, Alan G., E-mail: lynn@ece.unm.edu; Gilmore, Mark [Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2014-11-15

    Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ∼10{sup 4} T (100 Megagauss) over small volumes (∼10{sup −10}m{sup 3}) at high plasma densities (∼10{sup 28}m{sup −3}) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.

  6. Prospects for x-ray polarimetry measurements of magnetic fields in magnetized liner inertial fusion plasmas

    Science.gov (United States)

    Lynn, Alan G.; Gilmore, Mark

    2014-11-01

    Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ˜104 T (100 Megagauss) over small volumes (˜10-10m3) at high plasma densities (˜1028m-3) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.

  7. Modelling of turbulent impurity transport in fusion edge plasmas using measured and calculated ionization cross sections

    CERN Document Server

    Kendl, Alexander

    2014-01-01

    Turbulent transport of trace impurities impurities in the edge and scrape-off-layer of tokamak fusion plasmas is modelled by three dimensional electromagnetic gyrofluid computations including evolution of plasma profile gradients. The source function of impurity ions is dynamically computed from pre-determined measured and calculated electron impact ionization cross section data. The simulations describe the generation and further passive turbulent E-cross-B advection of the impurities by intermittent fluctuations and coherent filamentary structures (blobs) across the scrape-off-layer.

  8. Prospects for x-ray polarimetry measurements of magnetic fields in magnetized liner inertial fusion plasmas.

    Science.gov (United States)

    Lynn, Alan G; Gilmore, Mark

    2014-11-01

    Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ∼10(4) T (100 Megagauss) over small volumes (∼10(-10)m(3)) at high plasma densities (∼10(28)m(-3)) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.

  9. Fusion in the Era of Burning Plasma Studies: Workforce Planning for 2004 to 2014. Final report to FESA C

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2004-03-29

    This report has been prepared in response to Dr. R. Orbach’s request of the Fusion Energy Sciences Advisory Committee (FESAC) to “address the issue of workforce development in the U.S. fusion program.” The report addresses three key questions: what is the current status of the fusion science, technology, and engineering workforce; what is the workforce that will be needed and when it will be needed to ensure that the U.S. is an effective partner in ITER and to enable the U.S. to successfully carry out the fusion program; and, what can be done to ensure a qualified, diversified, and sufficiently large workforce and a pipeline to maintain that workforce? In addressing the charge, the Panel considers a workforce that allows for a vigorous national program of fusion energy research that includes participation in magnetic fusion (ITER) and inertial fusion (NIF) burning plasma experiments.

  10. Delay time embedding of mass loss avalanches in a fusion plasma-oriented sandpile model

    Science.gov (United States)

    Bowie, C. A.; Dendy, R. O.; Hole, M. J.

    2016-10-01

    The sandpile paradigm is widely used to model aspects of the phenomenology of magnetically confined fusion (MCF) plasmas, including enhanced confinement, edge pedestals and, potentially, the impulsive energy and particle release process known as ELMing. Here we identify new points of contact between ELMing and the systemwide avalanches in a sandpile. We compare the quantified response [Calderon et al., Phys. Plasmas 20, 042306 (2014)] to increased fuelling of the time sequence of edge localised mode events in a series of similar Joint European Torus plasmas with the response to increased fuelling of the time sequence of systemwide avalanches in a sandpile model [Chapman et al., Phys. Rev. Lett. 86, 2814 (2001)] that has well established links to MCF plasma phenomenology. Both the probability density functions of inter-event time intervals, and delay time embeddings of event time sequences, at different fuelling rates, show common features and point to shared underlying physics.

  11. Reaching High-Yield Fusion with a Slow Plasma Liner Compressing a Magnetized Target

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D D; Parks, P B

    2008-03-18

    Dynamics of the compression of a magnetized plasma target by a heavy liner made of partially ionized high high-Z material is discussed. A 'soft-landing' (shockless) mode of the liner deceleration is analyzed. Conclusion is drawn that such mode is possible for the liners whose thickness at the time of the first contact with the target is smaller than, roughly, 10% of the initial (un-compressed) target radius. A combination of the plasma liner with one or two glide cones allows for a direct access to the area near the center of the reactor chamber. One can then generate plasma target inside the plasma liner at the optimum time. The other advantage of the glide cones is that they can be used to deliver additional fuel to the center of the target near the point of a maximum compression and thereby increase the fusion yield.

  12. A DOE/Fusion Energy Sciences Research/Education Program at PVAMU Study of Rotamak Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Tian-Sen [Prairie View A& M Univ., Prairie View, TX (United States); Saganti, Premkumar [Prairie View A& M Univ., Prairie View, TX (United States)

    2017-02-17

    During recent years (2004-2015), with DOE support, the PVAMU plasma research group accomplished new instrumentation development, conducted several new plasma experiments, and is currently poised to advance with standing-wave microwave plasma propulsion research. On the instrumentation development, the research group completed: (i) building a new plasma chamber with metal CF flanges, (ii) setting up of a 6kW/2450MHz microwave input system as an additional plasma heating source at our rotamak plasma facility, (iii) installation of one programmatic Kepco ATE 6-100DMG fast DC current supply system used in rotamak plasma shape control experiment, built a new microwave, standing-wave experiment chamber and (iv) established a new plasma lab with field reversal configuration capability utilizing 1MHz/200kW RF (radio frequency) wave generator. Some of the new experiments conducted in this period also include: (i) assessment of improved magnetic reconnection at field-reversed configuration (FRC) plasma, (ii) introduction of microwave heating experiments, and (iii) suppression of n = 1 tilt instability by one coil with a smaller current added inside the rotamak’s central pipe. These experiments led to publications in Physical Review Letters, Reviews of Scientific Instruments, Division of Plasma Physics (DPP) of American Physical Society (APS) Reports, Physics of Plasmas Controlled Fusion, and Physics of Plasmas (between 2004 and 2015). With these new improvements and advancements, we also initiated and accomplished design and fabrication of a plasma propulsion system. Currently, we are assembling a plasma propulsion experimental system that includes a 5kW helicon plasma source, a 25 cm diameter plasma heating chamber with 1MHz/200kW RF power rotating magnetic field, and a 60 cm diameter plasma exhaust chamber, and expect to achieve a plasma mass flow of 0.1g/s with 60km/s ejection. We anticipate several propulsion applications in near future as we advance our capabilities

  13. Sites of glucose transporter-4 vesicle fusion with the plasma membrane correlate spatially with microtubules.

    Directory of Open Access Journals (Sweden)

    Jennine M Dawicki-McKenna

    Full Text Available In adipocytes, vesicles containing glucose transporter-4 (GLUT4 redistribute from intracellular stores to the cell periphery in response to insulin stimulation. Vesicles then fuse with the plasma membrane, facilitating glucose transport into the cell. To gain insight into the details of microtubule involvement, we examined the spatial organization and dynamics of microtubules in relation to GLUT4 vesicle trafficking in living 3T3-L1 adipocytes using total internal reflection fluorescence (TIRF microscopy. Insulin stimulated an increase in microtubule density and curvature within the TIRF-illuminated region of the cell. The high degree of curvature and abrupt displacements of microtubules indicate that substantial forces act on microtubules. The time course of the microtubule density increase precedes that of the increase in intensity of fluorescently-tagged GLUT4 in this same region of the cell. In addition, portions of the microtubules are highly curved and are pulled closer to the cell cortex, as confirmed by Parallax microscopy. Microtubule disruption delayed and modestly reduced GLUT4 accumulation at the plasma membrane. Quantitative analysis revealed that fusions of GLUT4-containing vesicles with the plasma membrane, detected using insulin-regulated aminopeptidase with a pH-sensitive GFP tag (pHluorin, preferentially occur near microtubules. Interestingly, long-distance vesicle movement along microtubules visible at the cell surface prior to fusion does not appear to account for this proximity. We conclude that microtubules may be important in providing spatial information for GLUT4 vesicle fusion.

  14. Analytic Models of High-Temperature Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Stygar, W.A.; Olson, R.E.; Spielman, R.B.; Leeper, R.J.

    2000-11-29

    A unified set of high-temperature-hohlraum models has been developed. For a simple hohlraum, P{sub s} = [A{sub s}+(1{minus}{alpha}{sub W})A{sub W}+A{sub H}]{sigma}T{sub R}{sup 4} + (4V{sigma}/c)(dT{sub R}{sup r}/dt) where P{sub S} is the total power radiated by the source, A{sub s} is the source area, A{sub W} is the area of the cavity wall excluding the source and holes in the wall, A{sub H} is the area of the holes, {sigma} is the Stefan-Boltzmann constant, T{sub R} is the radiation brightness temperature, V is the hohlraum volume, and c is the speed of light. The wall albedo {alpha}{sub W} {triple_bond} (T{sub W}/T{sub R}){sup 4} where T{sub W} is the brightness temperature of area A{sub W}. The net power radiated by the source P{sub N} = P{sub S}-A{sub S}{sigma}T{sub R}{sup 4}, which suggests that for laser-driven hohlraums the conversion efficiency {eta}{sub CE} be defined as P{sub N}/P{sub LASER}. The characteristic time required to change T{sub R}{sup 4} in response to a change in P{sub N} is 4V/C[(l{minus}{alpha}{sub W})A{sub W}+A{sub H}]. Using this model, T{sub R}, {alpha}{sub W}, and {eta}{sub CE} can be expressed in terms of quantities directly measurable in a hohlraum experiment. For a steady-state hohlraum that encloses a convex capsule, P{sub N} = {l_brace}(1{minus}{alpha}{sub W})A{sub W}+A{sub H}+[(1{minus}{alpha}{sub C})(A{sub S}+A{sub W}{alpha}{sub W})A{sub C}/A{sub T}]{r_brace}{sigma}T{sub RC}{sup 4} where {alpha}{sub C} is the capsule albedo, A{sub C} is the capsule area, A{sub T} {triple_bond} (A{sub S}+A{sub W}+A{sub H}), and T{sub RC} is the brightness temperature of the radiation that drives the capsule. According to this relation, the capsule-coupling efficiency of the baseline National-Ignition-Facility (NIF) hohlraum is 15% higher than predicted by previous analytic expressions. A model of a hohlraum that encloses a z pinch is also presented.

  15. Hohlraum Target Alignment from X-ray Detector Images using Starburst Design Patterns

    Energy Technology Data Exchange (ETDEWEB)

    Leach, R R; Conder, A; Edwards, O; Kroll, J; Kozioziemski, B; Mapoles, E; McGuigan, D; Wilhelmsen, K

    2010-12-14

    National Ignition Facility (NIF) is a high-energy laser facility comprised of 192 laser beams focused with enough power and precision on a hydrogen-filled spherical, cryogenic target to initiate a fusion reaction. The target container, or hohlraum, must be accurately aligned to an x-ray imaging system to allow careful monitoring of the frozen fuel layer in the target. To achieve alignment, x-ray images are acquired through starburst-shaped windows cut into opposite sides of the hohlraum. When the hohlraum is in alignment, the starburst pattern pairs match nearly exactly and allow a clear view of the ice layer formation on the edge of the target capsule. During the alignment process, x-ray image analysis is applied to determine the direction and magnitude of adjustment required. X-ray detector and source are moved in concert during the alignment process. The automated pointing alignment system described here is both accurate and efficient. In this paper, we describe the control and associated image processing that enables automation of the starburst pointing alignment.

  16. Neutron reactions in the hohlraum at the LLNL National Ignition Facility

    Science.gov (United States)

    Bradley, P. A.; Grim, G. P.; Hayes, A. C.; Jungman, Gerard; Rundberg, R. S.; Wilhelmy, J. B.; Hale, G. M.; Korzekwa, R. C.

    2012-07-01

    The National Ignition Facility (NIF) is designed to drive deuterium-tritium (DT) inertial confinement fusion targets to ignition using indirect radiation from laser energy captured in a hohlraum. The projected yields at NIF suggest that interactions of neutrons with the hohlraum can directly probe the neutron spectrum. Different physical parameters of the burning capsule can be probed by different neutron reactions. We suggest a variety of neutron reactions on the gold and uranium present in National Ignition Campaign hohlraums that will be useful for both neutron diagnostics and dosimetry at the NIF. The radiochemical daughter products may then be used to infer the neutron spectrum from the capsule. The downscattered neutrons may be studied by the (n,γ) and (n,n') reactions to infer the areal density of the capsule. The 14 MeV neutron fluence may be measured by (n,2n) daughter products for comparison to neutron spectrometer data. The hydrodynamical mix in the capsule can be studied with RIF neutrons, which are probed by (n,3n) reactions.

  17. Indirect drive ablative Rayleigh-Taylor experiments with rugby hohlraums on OMEGA

    Science.gov (United States)

    Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.-P.; Liberatore, S.; Vandenboomgaerde, M.

    2009-09-01

    Results of ablative Rayleigh-Taylor instability growth experiments performed in indirect drive on the OMEGA laser facility [T. R. Boehly, D. L. Brown, S. Craxton et al., Opt. Commun. 133, 495 (1997)] are reported. These experiments aim at benchmarking hydrocodes simulations and ablator instabilities growth in conditions relevant to ignition in the framework of the Laser MégaJoule [C. Cavailler, Plasma Phys. Controlled Fusion 47, 389 (2005)]. The modulated samples under study were made of germanium-doped plastic (CHGe), which is the nominal ablator for future ignition experiments. The incident x-ray drive was provided using rugby-shaped hohlraums [M. Vandenboomgaerde, J. Bastian, A. Casner et al., Phys. Rev. Lett. 99, 065004 (2007)] and was characterized by means of absolute time-resolved soft x-ray power measurements through a dedicated diagnostic hole, shock breakout data and one-dimensional and two-dimensional (2D) side-on radiographies. All these independent x-ray drive diagnostics lead to an actual on-foil flux that is about 50% smaller than laser-entrance-hole measurements. The experimentally inferred flux is used to simulate experimental optical depths obtained from face-on radiographies for an extensive set of initial conditions: front-side single-mode (wavelength λ =35, 50, and 70 μm) and two-mode perturbations (wavelength λ =35 and 70 μm, in phase or in opposite phase). Three-dimensional pattern growth is also compared with the 2D case. Finally the case of the feedthrough mechanism is addressed with rear-side modulated foils.

  18. Hohlraum calculations for the NIF opacity platform

    Science.gov (United States)

    Dodd, E. S.; Perry, T. S.; Tregillis, I. L.; Kline, J. L.; Heeter, R. F.; Liedahl, D. A.; Opachich, Y. P.

    2015-11-01

    A summary of initial hohlraum calculations for planned opacity experiments at the National Ignition Facility (NIF) will be given. The purpose of these experiments is to make LTE opacity measurements of iron at the same conditions as previous experiments on Sandia's Z facility: 156 eV and 190 eV. Ongoing discrepancies between opacity data and theory make corroborating data highly important. The target considered in these calculations is a standard cylindrical hohlraum, with diameter 5.75 mm, but baffles have been placed between the laser hot spot and the sample to maintain the iron in LTE. The hohlraum is driven with a 3 ns flat top laser pulse, but limited to 500 kJ and only the outer beams. The inner beams will be used to drive a capsule implosion, which backlights the iron for the absorption measurements. The iron itself is a thin disk, mixed with magnesium as a spectroscopic tracer, and tamped with beryllium to minimize expansion. A description of the experimental set-up will be given. Supported under the US DOE by the Los Alamos National Security, LLC under contract DE-AC52-06NA25396.

  19. High Foot Implosion Experiments in Rugby Hohlraums

    Science.gov (United States)

    Ralph, Joseph; Leidinger, J.-P.; Callahan, D.; Kaiser, P.; Morice, O.; Marion, D.; Moody, J. D.; Ross, J. S.; Amendt, P.; Kritcher, A. L.; Milovich, J. L.; Strozzi, D.; Hinkel, D.; Michel, P.; Berzak Hopkins, L.; Pak, A.; Dewald, E. L.; Divol, L.; Khan, S.; Rygg, R.; Hurricane, O.; Lawrence Livermore National Lab Team; CEA/DAM Team

    2015-11-01

    The rugby hohlraum design is aimed at providing uniform x-ray drive on the capsule while minimizing the need for crossed beam energy transfer (CBET). As part of a series of experiments at the NIF using rugby hohlraums, design improvements in dual axis shock tuning experiments produced some of the most symmetric shocks measured on implosion experiments at the NIF. Additionally, tuning of the in-flight shell and hot spot shape have demonstrated that capsules can be tuned between oblate and prolate with measured velocities of nearly 340 km/s. However, these experimental measurements were accompanied by high levels of Stimulated Raman Scattering (SRS) that may result from the long inner beam path length, reamplification of the inner SRS by the outers, significant (CBET) or a combination of these. All rugby shots results were achieved with lower levels of hot electrons that can preheat the DT fuel layer for increased adiabat and reduced areal density. Detailed results from these experiments and those planned throughout the summer will be presented and compared with results obtained from cylindrical hohlraums. This work performed under the auspices of U.S. Department of Energy by Lawrence Livermore National Lab under Contract DE-AC52-07NA27344.

  20. Forthcoming Break-Even Conditions of Tokamak Plasma Performance for Fusion Energy Development

    Science.gov (United States)

    Hiwatari, Ryoji; Okano, Kunihiko; Asaoka, Yoshiyuki; Tokimatsu, Koji; Konishi, Satoshi; Ogawa, Yuichi

    The present study reveals forthcoming break-even conditions of tokamak plasma performance for the fusion energy development. The first condition is the electric break-even condition, which means that the gross electric power generation is equal to the circulating power in a power plant. This is required for fusion energy to be recognized as a suitable candidate for an alternative energy source. As for the plasma performance (normalized beta value ΒN), confinement improvement factor for H-mode HH, the ratio of plasma density to Greenwald density fnGW), the electric break-even condition requires the simultaneous achievement of 1.2 market. By using a long-term world energy scenario, a break-even price for introduction of fusion energy in the year 2050 is estimated to lie between 65 mill/kWh and 135 mill/kWh under the constraint of 550 ppm CO2 concentration in the atmosphere. In the present study, this break-even price is applied to the economic break-even condition. However, because this break-even price is based on the present energy scenario including uncertainties, the economic break-even condition discussed here should not be considered the sufficient condition, but a necessary condition. Under the conditions of Btmax = 16 T, ηe = 40 %, plant availability 60 %, and a radial build with/without CS coil, the economic break-even condition requires ΒN ˜ 5.0 for 65 mill/kWh of lower break-even price case. Finally, the present study reveals that the demonstration of steady-state operation with ΒN ˜ 3.0 in the ITER project leads to the upper region of the break-even price in the present world energy scenario, which implies that it is necessary to improve the plasma performance beyond that of the ITER advanced plasma operation.

  1. PREFACE: Theory of Fusion Plasmas, 13th Joint Varenna-Lausanne International Workshop (2012)

    Science.gov (United States)

    Garbet, Xavier; Sauter, Olivier

    2012-12-01

    The 2012 joint Varenna-Lausanne international workshop on the theory of fusion plasmas has been very fruitful. A broad variety of topics were addressed, as usual covering turbulence, MHD, edge physic, RF wave heating and a taste of astrophysics. Moreover the scope of the meeting was extended this year to include the physics of materials and diagnostics for burning plasmas. This evolution reflects the complexity of problems at hand in fusion, in particular in the context of ITER construction. Long-standing problems without immediate consequences have sometimes become an urgent matter in that context. One may quote for instance the choice of plasma facing components or the design of control systems. Another characteristic of the meeting is the interplay between various domains of plasma physics. For instance MHD modes are now currently investigated with gyrokinetic codes, kinetic effects are more and more included in MHD stability analysis, and turbulence is now accounted for in wave propagation problems. This is the proof of cross-fertilization and it is certainly a healthy sign in our community. Finally introducing some novelty in the programme does not prevent us from respecting the traditions of the meeting. As usual a good deal of the presentations were dedicated to numerical simulations. Combining advanced numerical techniques with elaborated analytical theory is certainly a trademark of the Varenna-Lausanne conference, which was respected again this year. The quality and size of the scientific production is illustrated by the 26 papers which appear in the present volume of Journal of Physics: Conference Series, all refereed. We would also like to mention another set of 20 papers to be published in Plasma Physics and Controlled Fusion. We hope the readers will enjoy this special issue of JPCS and the one to come in PPCF. Xavier Garbet and Olivier Sauter October 26, 2012

  2. The materials irradiation experiment for testing plasma facing materials at fusion relevant conditions

    Science.gov (United States)

    Garrison, L. M.; Zenobia, S. J.; Egle, B. J.; Kulcinski, G. L.; Santarius, J. F.

    2016-08-01

    The Materials Irradiation Experiment (MITE-E) was constructed at the University of Wisconsin-Madison Inertial Electrostatic Confinement Laboratory to test materials for potential use as plasma-facing materials (PFMs) in fusion reactors. PFMs in fusion reactors will be bombarded with x-rays, neutrons, and ions of hydrogen and helium. More needs to be understood about the interactions between the plasma and the materials to validate their use for fusion reactors. The MITE-E simulates some of the fusion reactor conditions by holding samples at temperatures up to 1000 °C while irradiating them with helium or deuterium ions with energies from 10 to 150 keV. The ion gun can irradiate the samples with ion currents of 20 μA-500 μA; the typical current used is 72 μA, which is an average flux of 9 × 1014 ions/(cm2 s). The ion gun uses electrostatic lenses to extract and shape the ion beam. A variable power (1-20 W), steady-state, Nd:YAG laser provides additional heating to maintain a constant sample temperature during irradiations. The ion beam current reaching the sample is directly measured and monitored in real-time during irradiations. The ion beam profile has been investigated using a copper sample sputtering experiment. The MITE-E has successfully been used to irradiate polycrystalline and single crystal tungsten samples with helium ions and will continue to be a source of important data for plasma interactions with materials.

  3. Multiple angle measurement and modeling of M-band x-ray fluxes from vacuum hohlraum

    Science.gov (United States)

    Guo, Liang; Li, Shanwei; Li, Zhichao; Jing, Longfei; Xie, Xufei; Jiang, Xiaohua; Yang, Dong; Du, Huabin; Hou, Lifei; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen; Ding, Yongkun; Hu, Guangyue; Zheng, Jian

    2016-09-01

    The energetics experiment of vacuum gold hohlraums is implemented on the Shenguang-II laser facility. The total and M-band x-ray fluxes from the laser entrance holes are measured by the flat response x-ray diodes which are set at multiple angles with respect to the axis of the hohlraums. The measured M-band fractions are from 5.72% to 7.71%, which present a specific angular distribution. Based on the fact that the M-band x-rays are mainly emitted from the under-dense high-temperature plasmas, a simplified model is developed to give a quantitative prediction of the intensity, temporal behavior, and angular distribution of the M-band x-ray flux. The results obtained with our model are in good agreement with the experimental data, showing that our model can be a useful tool for M-band x-ray investigation.

  4. Modifications of the laser beam coherence inertial confinement fusion plasmas; Modifications des proprietes de coherence des faisceaux laser dans les plasmas de fusion par confinement inertiel

    Energy Technology Data Exchange (ETDEWEB)

    Grech, M

    2007-06-15

    Inertial confinement fusion by laser requires smoothed laser beam with well-controlled coherence properties. Such beams are made of many randomly distributed intensity maxima: the so-called speckles. As the laser beam propagates through plasma its temporal and spatial coherence can be reduced. This phenomenon is called plasma induced smoothing. For high laser intensities, instabilities developing independently inside the speckles are responsible for the coherence loss. At lower intensities, only collective effects, involving many speckles, can lead to induced smoothing. This thesis is a theoretical, numerical and experimental study of these mechanisms. Accounting for the partially incoherent behavior of the laser beams requires the use of statistical description of the laser-plasma interaction. A model is developed for the multiple scattering of the laser light on the self-induced density perturbations that is responsible for a spreading of the temporal and spatial spectra of the transmitted light. It also serves as a strong seed for the instability of forward stimulated Brillouin scattering that induces both, angular spreading and red-shift of the transmitted light. A statistical model is developed for this instability. A criterion is obtained that gives a laser power (below the critical power for filamentation) above which the instability growth is important. Numerical simulations with the interaction code PARAX and an experiment performed on the ALISE laser facility confirm the importance of these forward scattering mechanisms in the modification of the laser coherence properties. (author)

  5. Dynamical interplay between fluctuations, electric fields and transport in fusion plasmas

    Indian Academy of Sciences (India)

    C Hidalgo; B Gonçalves; M A Pedrosa

    2003-12-01

    A view of recent experimental results and progress in the characterization of the statistical properties of electrostatic turbulence in magnetically confined devices is given. An empirical similarity in the scaling properties of the probability distribution function (PDF) of turbulent transport has been observed in the plasma edge region in fusion plasmas. The investigation of the dynamical interplay between fluctuation in gradients, turbulent transport and radial electric fields has shown that these parameters are strongly coupled both in tokamak and stellarator plasmas. The bursty behaviour of turbulent transport is linked with a departure from the most probable radial gradient. The dynamical relation between fluctuations in gradients and transport is strongly affected by the presence of sheared poloidal flows which organized themselves near marginal stability. These results emphasize the importance of the statistical description of transport processes in fusion plasmas as an alternative approach to the traditional way to characterize transport based on the computation of effective transport coefficients.

  6. Liquid Metals as Plasma-facing Materials for Fusion Energy Systems: From Atoms to Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Stone, Howard A. [Princeton Univ., NJ (United States); Koel, Bruce E. [Princeton Univ., NJ (United States); Bernasek, Steven L. [Princeton Univ., NJ (United States); Carter, Emily A. [Princeton Univ., NJ (United States); Debenedetti, Pablo G. [Princeton Univ., NJ (United States); Panagiotopoulos, Athanassios Z. [Princeton Univ., NJ (United States)

    2017-06-23

    The objective of our studies was to advance our fundamental understanding of liquid metals as plasma-facing materials for fusion energy systems, with a broad scope: from atoms to tokamaks. The flow of liquid metals offers solutions to significant problems of the plasma-facing materials for fusion energy systems. Candidate metals include lithium, tin, gallium, and their eutectic combinations. However, such liquid metal solutions can only be designed efficiently if a range of scientific and engineering issues are resolved that require advances in fundamental fluid dynamics, materials science and surface science. In our research we investigated a range of significant and timely problems relevant to current and proposed engineering designs for fusion reactors, including high-heat flux configurations that are being considered by leading fusion energy groups world-wide. Using experimental and theoretical tools spanning atomistic to continuum descriptions of liquid metals, and bridging surface chemistry, wetting/dewetting and flow, our research has advanced the science and engineering of fusion energy materials and systems. Specifically, we developed a combined experimental and theoretical program to investigate flows of liquid metals in fusion-relevant geometries, including equilibrium and stability of thin-film flows, e.g. wetting and dewetting, effects of electromagnetic and thermocapillary fields on liquid metal thin-film flows, and how chemical interactions and the properties of the surface are influenced by impurities and in turn affect the surface wetting characteristics, the surface tension, and its gradients. Because high-heat flux configurations produce evaporation and sputtering, which forces rearrangement of the liquid, and any dewetting exposes the substrate to damage from the plasma, our studies addressed such evaporatively driven liquid flows and measured and simulated properties of the different bulk phases and material interfaces. The range of our studies

  7. The interaction of the near-field plasma with antennas used in magnetic fusion research

    Science.gov (United States)

    Caughman, John

    2015-09-01

    Plasma heating and current drive using antennas in the Ion Cyclotron Range of Frequencies (ICRF) are important elements for the success of magnetic fusion. The antennas must operate in a harsh environment, where local plasma densities can be >1018/m3, magnetic fields can range from 0.2-5 Tesla, and antenna operating voltages can be >40 kV. This environment creates operational issues due to the interaction of the near-field of the antenna with the local plasma. In addition to parasitic losses in this plasma region, voltage and current distributions on the antenna structure lead to the formation of high electric fields and RF plasma sheaths, which can lead to enhanced particle and energy fluxes on the antenna and on surfaces intersected by magnetic field lines connected to or passing near the antenna. These issues are being studied using a simple electrode structure and a single-strap antenna on the Prototype Materials Plasma EXperiment (Proto-MPEX) at ORNL, which is a linear plasma device that uses an electron Bernstein wave heated helicon plasma source to create a high-density plasma suitable for use in a plasma-material interaction test stand. Several diagnostics are being used to characterize the near-field interactions, including double-Langmuir probes, a retarding field energy analyzer, and optical emission spectroscopy. The RF electric field is being studied utilizing Dynamic Stark Effect spectroscopy and Doppler-Free Saturation Spectroscopy. Recent experimental results and future plans will be presented. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under Contract DE-AC-05-00OR22725.

  8. Use of Polycarbonate Vacuum Vessels in High-Temperature Fusion-Plasma Research

    Energy Technology Data Exchange (ETDEWEB)

    B. Berlinger, A. Brooks, H. Feder, J. Gumbas, T. Franckowiak and S.A. Cohen

    2012-09-27

    Magnetic fusion energy (MFE) research requires ultrahigh-vacuum (UHV) conditions, primarily to reduce plasma contamination by impurities. For radiofrequency (RF)-heated plasmas, a great benefit may accrue from a non-conducting vacuum vessel, allowing external RF antennas which avoids the complications and cost of internal antennas and high-voltage high-current feedthroughs. In this paper we describe these and other criteria, e.g., safety, availability, design flexibility, structural integrity, access, outgassing, transparency, and fabrication techniques that led to the selection and use of 25.4-cm OD, 1.6-cm wall polycarbonate pipe as the main vacuum vessel for an MFE research device whose plasmas are expected to reach keV energies for durations exceeding 0.1 s

  9. Observation of Multiple Reconnections during Self-organization Process of High Temperature Fusion Plasma

    Science.gov (United States)

    Park, H. K.; Tobias, B.; Choi, M. J.; Yun, G. S.; Domier, C. W.; Luhmann, N. C., Jr.; Munsat, T.; Donné, A. J. H.; Spakman, G. W.; Textor Team

    2011-10-01

    Images of a high resolution 2-D Electron Cyclotron Emission Imaging (ECEI) diagnostic shows evidence of multiple magnetic reconnection processes during the internal disruption of a high temperature tokamak plasmas. The disruption induces magnetic self-organization of the toroidal plasma being accompanied by successive or simultaneous multiple layer reconnection. The degree of asymmetric deformation of the internal magnetic structure (m/n=1/1 mode) prior to temperature crash influences the outcome of the disruptive behavior. The observation is critical for the building block of first principle theoretical modeling of the sawtooth oscillation in current driven toroidal plasmas and the understandings can be applied to the impulsive disruptive behavior in flares of the solar, accretion disk and stellar coronae, Earth magnetospheric storms, and controlled fusion. Work supported by the NRF of Korea, the US DOE, the NWO of the Netherlands, and the EURATOM-FOM association.

  10. Energetic Particle Physics In Fusion Research In Preparation For Burning Plasma Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gorelenkov, Nikolai N [PPPL

    2013-06-01

    The area of energetic particle (EP) physics of fusion research has been actively and extensively researched in recent decades. The progress achieved in advancing and understanding EP physics has been substantial since the last comprehensive review on this topic by W.W. Heidbrink and G.J. Sadler [1]. That review coincided with the start of deuterium-tritium (DT) experiments on Tokamak Fusion Test reactor (TFTR) and full scale fusion alphas physics studies. Fusion research in recent years has been influenced by EP physics in many ways including the limitations imposed by the "sea" of Alfven eigenmodes (AE) in particular by the toroidicityinduced AEs (TAE) modes and reversed shear Alfven (RSAE). In present paper we attempt a broad review of EP physics progress in tokamaks and spherical tori since the first DT experiments on TFTR and JET (Joint European Torus) including helical/stellarator devices. Introductory discussions on basic ingredients of EP physics, i.e. particle orbits in STs, fundamental diagnostic techniques of EPs and instabilities, wave particle resonances and others are given to help understanding the advanced topics of EP physics. At the end we cover important and interesting physics issues toward the burning plasma experiments such as ITER (International Thermonuclear Experimental Reactor).

  11. Millimeter-wave imaging of magnetic fusion plasmas: technology innovations advancing physics understanding

    Science.gov (United States)

    Wang, Y.; Tobias, B.; Chang, Y.-T.; Yu, J.-H.; Li, M.; Hu, F.; Chen, M.; Mamidanna, M.; Phan, T.; Pham, A.-V.; Gu, J.; Liu, X.; Zhu, Y.; Domier, C. W.; Shi, L.; Valeo, E.; Kramer, G. J.; Kuwahara, D.; Nagayama, Y.; Mase, A.; Luhmann, N. C., Jr.

    2017-07-01

    Electron cyclotron emission (ECE) imaging is a passive radiometric technique that measures electron temperature fluctuations; and microwave imaging reflectometry (MIR) is an active radar imaging technique that measures electron density fluctuations. Microwave imaging diagnostic instruments employing these techniques have made important contributions to fusion science and have been adopted at major fusion facilities worldwide including DIII-D, EAST, ASDEX Upgrade, HL-2A, KSTAR, LHD, and J-TEXT. In this paper, we describe the development status of three major technological advancements: custom mm-wave integrated circuits (ICs), digital beamforming (DBF), and synthetic diagnostic modeling (SDM). These have the potential to greatly advance microwave fusion plasma imaging, enabling compact and low-noise transceiver systems with real-time, fast tracking ability to address critical fusion physics issues, including ELM suppression and disruptions in the ITER baseline scenario, naturally ELM-free states such as QH-mode, and energetic particle confinement (i.e. Alfvén eigenmode stability) in high-performance regimes that include steady-state and advanced tokamak scenarios. Furthermore, these systems are fully compatible with today’s most challenging non-inductive heating and current drive systems and capable of operating in harsh environments, making them the ideal approach for diagnosing long-pulse and steady-state tokamaks.

  12. Generation and compression of a target plasma for magnetized target fusion

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, R.C.; Lindemuth, I.R.; Sheehey, P.T. [and others

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Magnetized target fusion (MTF) is intermediate between the two very different approaches to fusion: inertial and magnetic confinement fusion (ICF and MCF). Results from collaboration with a Russian MTF team on their MAGO experiments suggest they have a target plasma suitable for compression to provide an MTF proof of principle. This LDRD project had tow main objectives: first, to provide a computational basis for experimental investigation of an alternative MTF plasma, and second to explore the physics and computational needs for a continuing program. Secondary objectives included analytic and computational support for MTF experiments. The first objective was fulfilled. The second main objective has several facets to be described in the body of this report. Finally, the authors have developed tools for analyzing data collected on the MAGO a nd LDRD experiments, and have tested them on limited MAGO data.

  13. Model-independent determination of the astrophysical S-factor in laser-induced fusion plasmas

    CERN Document Server

    Lattuada, D; Bonasera, A; Bang, W; Quevedo, H J; Warren, M; Consoli, F; De Angelis, R; Andreoli, P; Kimura, S; Dyer, G; Bernstein, A C; Hagel, K; Barbui, M; Schmidt, K; Gaul, E; Donovan, M E; Natowitz, J B; Ditmire, T

    2016-01-01

    In this work, we present a new and general method for measuring the astrophysical S-factor of nuclear reactions in laser-induced plasmas and we apply it to d(d,n)$^{3}$He. The experiment was performed with the Texas Petawatt laser, which delivered 150-270 fs pulses of energy ranging from 90 to 180 J to D$_{2}$ or CD$_{4}$ molecular clusters. After removing the background noise, we used the measured time-of-flight data of energetic deuterium ions to obtain their energy distribution. We derive the S-factor using the measured energy distribution of the ions, the measured volume of the fusion plasma and the measured fusion yields. This method is model-independent in the sense that no assumption on the state of the system is required, but it requires an accurate measurement of the ion energy distribution especially at high energies and of the relevant fusion yields. In the d(d,n)$^{3}$He and $^{3}$He(d,p)$^{4}$He cases discussed here, it is very important to apply the background subtraction for the energetic ions ...

  14. D-D nuclear fusion processes induced in polyethylene foams by TW Laser-generated plasma

    Science.gov (United States)

    Torrisi, L.; Cutroneo, M.; Cavallaro, S.; Ullschmied, J.

    2015-06-01

    Deuterium-Deuterium fusion processes were generated by focusing the 3 TW PALS Laser on solid deuterated polyethylene targets placed in vacuum. Deuterium ion acceleration of the order of 4 MeV was obtained using laser irradiance Iλ2 ˜ 5 × 1016 W μm2/cm2 on the target. Thin and thick targets, at low and high density, were irradiated and plasma properties were monitored "on line" and "off line". The ion emission from plasma was monitored with Thomson Parabola Spectrometer, track detectors and ion collectors. Fast semiconductor detectors based on SiC and fast plastic scintillators, both employed in time-of-flight configuration, have permitted to detect the characteristic 3.0 MeV protons and 2.45 MeV neutrons emission from the nuclear fusion reactions. From massive absorbent targets we have evaluated the neutron flux by varying from negligible values up to about 5 × 107 neutrons per laser shot in the case of foams targets, indicating a reaction rate of the order of 108 fusion events per laser shot using "advanced targets".

  15. Refined Calculations of Secondary Nuclear Reactions in Magneto-Inertial Fusion Plasmas

    Science.gov (United States)

    Schmit, Paul; Knapp, Patrick; Hansen, Stephanie; Gomez, Matthew; Hahn, Kelly; Sinars, Daniel; Peterson, Kyle; Slutz, Stephen; Sefkow, Adam; Awe, Thomas; Harding, Eric; Jennings, Christopher

    2014-10-01

    Diagnosing the degree of magnetic flux compression at stagnation in magneto-inertial fusion (MIF) is critical for charting the performance of any MIF concept. In pure deuterium plasma, the transport of high-energy tritons produced by the aneutronic DD fusion reaction depends strongly on the magnetic field. The tritons probe and occasionally react with the fuel, emitting secondary DT neutrons. We show that the DT/DD neutron yield ratio and the secondary DT neutron spectra can be used to infer the magnetic field-radius product (BR), the critical confinement parameter for MIF. The amount of fuel-pusher mix also can be constrained by secondary reactions. We discuss the sensitivity to plasma inhomogeneities of the calculations and outline methods to relate secondary yields to alpha particle energy deposition in ignition-relevant experiments employing DT fuel. We compare our calculations to recent tests of the Magnetized Liner Inertial Fusion (MagLIF) concept on the Z Pulsed Power Facility. Supported in part by the SNL Truman Fellowship, which is part of the LDRD Program, and sponsored by Sandia Corporation (a wholly owned subsidiary of Lockheed Martin Corporation) as Operator of SNL under its U.S. DoE Contract No. DE-AC04-94AL85000.

  16. D-D nuclear fusion processes induced in polyethylene foams by TW Laser-generated plasma

    Directory of Open Access Journals (Sweden)

    Torrisi L.

    2015-01-01

    Full Text Available Deuterium-Deuterium fusion processes were generated by focusing the 3 TW PALS Laser on solid deuterated polyethylene targets placed in vacuum. Deuterium ion acceleration of the order of 4 MeV was obtained using laser irradiance Iλ2 ∼ 5 × 1016 W μm2/cm2 on the target. Thin and thick targets, at low and high density, were irradiated and plasma properties were monitored “on line” and “off line”. The ion emission from plasma was monitored with Thomson Parabola Spectrometer, track detectors and ion collectors. Fast semiconductor detectors based on SiC and fast plastic scintillators, both employed in time-of-flight configuration, have permitted to detect the characteristic 3.0 MeV protons and 2.45 MeV neutrons emission from the nuclear fusion reactions. From massive absorbent targets we have evaluated the neutron flux by varying from negligible values up to about 5 × 107 neutrons per laser shot in the case of foams targets, indicating a reaction rate of the order of 108 fusion events per laser shot using “advanced targets”.

  17. pF3D Simulations of Large Outer-Beam Brillouin Scattering from NIF Rugby Hohlraums

    Science.gov (United States)

    Langer, Steven; Strozzi, David; Chapman, Thomas; Amendt, Peter

    2015-11-01

    We assess the cause of large outer-beam stimulated Brillouin scattering (SBS) in a NIF shot with a rugby-shaped hohlraum, which has less wall surface loss and thus higher x-ray drive than a cylindrical hohlraum of the same radius. This shot differed from a prior rugby shot with low SBS in three ways: outer beam pointing, split-pointing of the four beams within each outer-beam quadruplet, and a small amount of neon added to the hohlraum helium fill gas. We use pF3D, a massively-parallel, paraxial-envelope laser plasma interaction code, with plasma profiles from the radiation-hydrodynamics code Lasnex. We determine which change between the two shots increased the SBS by adding them one at a time to the simulations. We compare the simulations to experimental data for total SBS power, its spatial distribution at the lens, and the SBS spectrum. For each shot, we use profiles from Lasnex simulations with and without a model for mix at the hohlraum wall-gas interface. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-674893.

  18. Real-time wavelet detection of crashes in limit cycles of non-stationary fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Berkel, M. van, E-mail: m.v.berkel@tue.nl [Eindhoven University of Technology, Department of Mechanical Engineering, Control Systems Technology Group, PO Box 513, 5600 MB Eindhoven (Netherlands); FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Witvoet, G.; Baar, M.R. de [Eindhoven University of Technology, Department of Mechanical Engineering, Control Systems Technology Group, PO Box 513, 5600 MB Eindhoven (Netherlands); FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Nuij, P.W.J.M. [Eindhoven University of Technology, Department of Mechanical Engineering, Control Systems Technology Group, PO Box 513, 5600 MB Eindhoven (Netherlands); Morsche, H.G. ter [Eindhoven University of Technology, Department of Mathematics and Computer Science, PO Box 513, 5600 MB Eindhoven (Netherlands); Steinbuch, M. [Eindhoven University of Technology, Department of Mechanical Engineering, Control Systems Technology Group, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer We propose a new wavelet-based method for accurate and robust detection of limit cycle crashes in fusion plasmas. Black-Right-Pointing-Pointer The method is optimized for real-time applications such that it has small delay. Black-Right-Pointing-Pointer The method is implemented in a real-time algorithm and is tested on experimental data. Black-Right-Pointing-Pointer Almost all crashes are detected flawlessly including off-waveforms with high SNR. - Abstract: The high performance mode (H-mode) is one of the baseline plasma scenarios for the experimental fusion reactor ITER. This scenario features a periodic crash-like reorganization of the plasma pressure and the magnetic flux in the plasma core and plasma periphery. The core instability is often referred to as the sawtooth instability while the instability at the edge of the plasma is referred to as ELM. In this paper we present an algorithm for optimized (low latency, robust and high fidelity) real-time sensing of the crashes. The algorithm is based on time-scale wavelet theory and edge-detection. It is argued that detection of crashes has considerably less delay than the other methods. The realized accuracy of the detection algorithm is well below the uncertainty of the crash period for most crashes. Multiresolution analysis enables distinction between different sizes of sawtooth crashes due to the different sizes of wavelets (scales), resulting in an algorithm, which is robust and accurate. Although strictly speaking, the crash detection method is demonstrated for sawteeth measured with ECE only, it can be applied to any periodic crash, measured with any temporally resolved data. Note that the possibility of differentiating between crash like events of different nature depends on their individual time-scales and used measurement setup.

  19. Progress towards a more predictive model for hohlraum radiation drive and symmetry

    Science.gov (United States)

    Jones, Ogden

    2016-10-01

    The high flux model (HFM) was first developed to match emission levels observed from Au spheres illuminated symmetrically at the UR-LLE OMEGA laser. It utilizes a modern non-LTE atomic physics model and an electron thermal flux limiter of 0.15 or a non-local electron transport model. Shortly thereafter, the HFM was also found to better match the radiation drive observed through the laser entrance hole of laser-heated vacuum hohlraums on the NIF. Subsequent capsule implosion experiments driven by hohlraums filled with 1-1.6 mg/cc of He, having case-to-capsule ratios of 2.6, and pulse lengths 15-20 ns have been characterized by relatively large amounts of laser backscatter losses (up to 18% of the input laser energy). They have also utilized cross beam energy transfer (CBET) to transfer power to the lasers depositing energy near the hohlraum waist. When the HFM is applied to these experiments, the hohlraum x-ray drive is over-predicted by 20-30% during peak laser power, and the drive symmetry cannot be matched without making ad hoc corrections. More recent experiments using hohlraum fills from 0-0.6 mg/cc He, case-to-capsule ratios 3-4, and pulse lengths 6-10 ns have little or no CBET or backscatter and are in better agreement with calculations using the HFM, although discrepancies remain. Uncertainties remaining in the computational models of emissivity, laser absorption, heat transport, etc. used in our hydrodynamic codes can significantly affect predictions. In this work we test various physically-plausible adjustments or alternatives to these models in order to find a more predictive model for radiation drive in the regime with little or no backscatter or CBET. We utilize measurements of the radiation drive, shape and trajectory of the imploding shell, shape of the stagnated hot spot, and bang time in capsule implosions and spectroscopic measurements of the hohlraum plasma conditions to compare against high resolution hydrodynamic calculations using the various

  20. Energy-dependent finite-orbit treatment for plasma buildup in mirror fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, M.M.

    1980-01-01

    A computer simulation of hot plasma buildup in mirror fusion devices and results from this model are presented. In a small, hot magnetically confined plasma, the ion orbit radius (rho/sub i/) can be comparable to the plasma radius (R/sub p/). It a mirror-confined plasma were rho/sub i//R/sub p/ > 1/25 (such as 2XII-B), a point kinetic treatment of ion interactions becomes inaccurate and a finite gyro-radius (FGR) treatment must be used to adequately describe plasma buildup processes. This is particularly true for describing losses due to cold-gas charge exchange (c-x) near the plasma surface, since a particle lost near the vacuum interface may have contributed to the density as far as 2 rho/sub i/ radially inward from the c-x point. A similar FGR effect applies to beam-deposited ions whose large orbits influence the density up to 2 rho/sub i/ from the trapping point.

  1. A Novel Spectrometer for Measuring Laser-Produced Plasma X-Ray in Inertial Confinement Fusion

    Directory of Open Access Journals (Sweden)

    Zhu Gang

    2012-01-01

    Full Text Available In the experimental investigations of inertial confinement fusion, the laser-produced high-temperature plasma contains very abundant information, such as the electron temperature and density, ionization. In order to diagnose laser-plasma distribution in space and evolution in time, an elliptical curved crystal spectrometer has been developed and applied to diagnose X-ray of laser-produced plasma in 0.2~2.46 nm region. According to the theory of Bragg diffraction, four kinds of crystal including LiF, PET, MiCa, and KAP were chosen as dispersive elements. The distance of crystal lattice varies from 0.4 to 2.6 nm. Bragg angle is in the range of 30°~67.5°, and the spectral detection angle is in 55.4°~134°. The curved crystal spectrometer mainly consists of elliptical curved crystal analyzer, vacuum configuration, aligning device, spectral detectors and three-dimensional microadjustment devices. The spectrographic experiment was carried out on the XG-2 laser facility. Emission spectrum of Al plasmas, Ti plasma, and Au plasmas have been successfully recorded by using X-ray CCD camera. It is demonstrated experimentally that the measured wavelength is accorded with the theoretical value.

  2. Laser propagation measurements in long-scale-length underdense plasmas relevant to magnetized liner inertial fusion

    Science.gov (United States)

    Harvey-Thompson, A. J.; Sefkow, A. B.; Wei, M. S.; Nagayama, T.; Campbell, E. M.; Blue, B. E.; Heeter, R. F.; Koning, J. M.; Peterson, K. J.; Schmitt, A.

    2016-11-01

    We report experimental results and simulations showing efficient laser energy coupling into plasmas at conditions relevant to the magnetized liner inertial fusion (MagLIF) concept. In MagLIF, to limit convergence and increase the hydrodynamic stability of the implosion, the fuel must be efficiently preheated. To determine the efficiency and physics of preheating by a laser, an Ar plasma with ne/nc r i t˜0.04 is irradiated by a multi-ns, multi-kJ, 0.35-μm, phase-plate-smoothed laser at spot-averaged intensities ranging from 1.0 ×1014 to 2.5 ×1014W /c m2 and pulse widths from 2 to 10 ns. Time-resolved x-ray images of the laser-heated plasma are compared to two-dimensional radiation-hydrodynamic simulations that show agreement with the propagating emission front, a comparison that constrains laser energy deposition to the plasma. The experiments show that long-pulse, modest-intensity (I =1.5 ×1014W /c m2 ) beams can efficiently couple energy (˜82 % of the incident energy) to MagLIF-relevant long-length (9.5 mm) underdense plasmas. The demonstrated heating efficiency is significantly higher than is thought to have been achieved in early integrated MagLIF experiments [A. B. Sefkow et al., Phys. Plasmas 21, 072711 (2014), 10.1063/1.4890298].

  3. First Investigation on the Radiation Field of the Spherical Hohlraum

    Science.gov (United States)

    Huo, Wen Yi; Li, Zhichao; Chen, Yao-Hua; Xie, Xuefei; Lan, Ke; Liu, Jie; Ren, Guoli; Li, Yongsheng; Liu, Yonggang; Jiang, Xiaohua; Yang, Dong; Li, Sanwei; Guo, Liang; Zhang, Huan; Hou, Lifei; Du, Huabing; Peng, Xiaoshi; Xu, Tao; Li, Chaoguang; Zhan, Xiayu; Yuan, Guanghui; Zhang, Haijun; Jiang, Baibin; Huang, Lizhen; Du, Kai; Zhao, Runchang; Li, Ping; Wang, Wei; Su, Jingqin; Ding, Yongkun; He, Xian-Tu; Zhang, Weiyan

    2016-07-01

    The first spherical hohlraum energetics experiment is accomplished on the SGIII-prototype laser facility. In the experiment, the radiation temperature is measured by using an array of flat-response x-ray detectors (FXRDs) through a laser entrance hole at four different angles. The radiation temperature and M -band fraction inside the hohlraum are determined by the shock wave technique. The experimental observations indicate that the radiation temperatures measured by the FXRDs depend on the observation angles and are related to the view field. According to the experimental results, the conversion efficiency of the vacuum spherical hohlraum is in the range from 60% to 80%. Although this conversion efficiency is less than the conversion efficiency of the near vacuum hohlraum on the National Ignition Facility, it is consistent with that of the cylindrical hohlraums used on the NOVA and the SGIII-prototype at the same energy scale.

  4. Self-organized helical equilibria as a new paradigm for ohmically heated fusion plasmas

    Science.gov (United States)

    Lorenzini, R.; Martines, E.; Piovesan, P.; Terranova, D.; Zanca, P.; Zuin, M.; Alfier, A.; Bonfiglio, D.; Bonomo, F.; Canton, A.; Cappello, S.; Carraro, L.; Cavazzana, R.; Escande, D. F.; Fassina, A.; Franz, P.; Gobbin, M.; Innocente, P.; Marrelli, L.; Pasqualotto, R.; Puiatti, M. E.; Spolaore, M.; Valisa, M.; Vianello, N.; Martin, P.; Martin, P.; Apolloni, L.; Puiatti, M. E.; Adamek, J.; Agostini, M.; Alfier, A.; Annibaldi, S. V.; Antoni, V.; Auriemma, F.; Barana, O.; Baruzzo, M.; Bettini, P.; Bolzonella, T.; Bonfiglio, D.; Bonomo, F.; Brombin, M.; Brotankova, J.; Buffa, A.; Buratti, P.; Canton, A.; Cappello, S.; Carraro, L.; Cavazzana, R.; Cavinato, M.; Chapman, B. E.; Chitarin, G.; Dal Bello, S.; de Lorenzi, A.; de Masi, G.; Escande, D. F.; Fassina, A.; Ferro, A.; Franz, P.; Gaio, E.; Gazza, E.; Giudicotti, L.; Gnesotto, F.; Gobbin, M.; Grando, L.; Guazzotto, L.; Guo, S. C.; Igochine, V.; Innocente, P.; Liu, Y. Q.; Lorenzini, R.; Luchetta, A.; Manduchi, G.; Marchiori, G.; Marcuzzi, D.; Marrelli, L.; Martini, S.; Martines, E.; McCollam, K.; Milani, F.; Moresco, M.; Novello, L.; Ortolani, S.; Paccagnella, R.; Pasqualotto, R.; Peruzzo, S.; Piovan, R.; Piovesan, P.; Piron, L.; Pizzimenti, A.; Pomaro, N.; Predebon, I.; Reusch, J. A.; Rostagni, G.; Rubinacci, G.; Sarff, J. S.; Sattin, F.; Scarin, P.; Serianni, G.; Sonato, P.; Spada, E.; Soppelsa, A.; Spagnolo, S.; Spolaore, M.; Spizzo, G.; Taliercio, C.; Terranova, D.; Toigo, V.; Valisa, M.; Vianello, N.; Villone, F.; White, R. B.; Yadikin, D.; Zaccaria, P.; Zamengo, A.; Zanca, P.; Zaniol, B.; Zanotto, L.; Zilli, E.; Zohm, H.; Zuin, M.

    2009-08-01

    In the quest for new energy sources, the research on controlled thermonuclear fusion has been boosted by the start of the construction phase of the International Thermonuclear Experimental Reactor (ITER). ITER is based on the tokamak magnetic configuration, which is the best performing one in terms of energy confinement. Alternative concepts are however actively researched, which in the long term could be considered for a second generation of reactors. Here, we show results concerning one of these configurations, the reversed-field pinch (RFP). By increasing the plasma current, a spontaneous transition to a helical equilibrium occurs, with a change of magnetic topology. Partially conserved magnetic flux surfaces emerge within residual magnetic chaos, resulting in the onset of a transport barrier. This is a structural change and sheds new light on the potential of the RFP as the basis for a low-magnetic-field ohmic fusion reactor.

  5. Gyrokinetic simulations of fusion plasmas using a spectral velocity space representation

    CERN Document Server

    Parker, Joseph Thomas

    2016-01-01

    Magnetic confinement fusion reactors suffer severely from heat and particle losses through turbulent transport, which has inspired the construction of ever larger and more expensive reactors. Numerical simulations are vital to their design and operation, but particle collisions are too infrequent for fluid descriptions to be valid. Instead, strongly magnetised fusion plasmas are described by the gyrokinetic equations, a nonlinear integro-differential system for evolving the particle distribution functions in a five-dimensional position and velocity space, and the consequent electromagnetic field. Due to the high dimensionality, simulations of small reactor sections require hundreds of thousands of CPU hours on High Performance Computing platforms. We develop a Hankel-Hermite spectral representation for velocity space that exploits structural features of the gyrokinetic system. The representation exactly conserves discrete free energy in the absence of explicit dissipation, while our Hermite hypercollision ope...

  6. Properties of the ion-ion hybrid resonator in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Morales, George J. [Univ. of California, Los Angeles, CA (United States)

    2015-10-06

    The project developed theoretical and numerical descriptions of the properties of ion-ion hybrid Alfvén resonators that are expected to arise in the operation of a fusion reactor. The methodology and theoretical concepts were successfully compared to observations made in basic experiments in the LAPD device at UCLA. An assessment was made of the excitation of resonator modes by energetic alpha particles for burning plasma conditions expected in the ITER device. The broader impacts included the generation of basic insight useful to magnetic fusion and space science researchers, defining new avenues for exploration in basic laboratory experiments, establishing broader contacts between experimentalists and theoreticians, completion of a Ph.D. dissertation, and promotion of interest in science through community outreach events and classroom instruction.

  7. Magnetic stochasticity in magnetically confined fusion plasmas chaos of field lines and charged particle dynamics

    CERN Document Server

    Abdullaev, Sadrilla

    2014-01-01

    This is the first book to systematically consider the modern aspects of chaotic dynamics of magnetic field lines and charged particles in magnetically confined fusion plasmas.  The analytical models describing the generic features of equilibrium magnetic fields and  magnetic perturbations in modern fusion devices are presented. It describes mathematical and physical aspects of onset of chaos, generic properties of the structure of stochastic magnetic fields, transport of charged particles in tokamaks induced by magnetic perturbations, new aspects of particle turbulent transport, etc. The presentation is based on the classical and new unique mathematical tools of Hamiltonian dynamics, like the action--angle formalism, classical perturbation theory, canonical transformations of variables, symplectic mappings, the Poincaré-Melnikov integrals. They are extensively used for analytical studies as well as for numerical simulations of magnetic field lines, particle dynamics, their spatial structures and  statisti...

  8. Fusion performances and alpha heating in future JET D-T plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Balet, B.; Cordey, J.G.; Gibson, A.; Lomas, P.; Stubberfield, P.M.; Thomas, P. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    The new pump divertor installed at JET should allow high performance pulses of a few seconds duration by both preventing the impurity influx and controlling the density evolution. The TRANSP code has been used in a predictive mode to assess the possible fusion performance of such plasmas fuelled with a 50:50 mixture of D and T, and the effect of alpha particles heating on Te and Ti. Several cases are considered: 50:50 D-T mix; 50:50 D-T mix, no C bloom; 50:50 D-T mix, VH phase, density control; 50:50 D-T mix, VH phase, density control, 6 Ma. The predictions show that if the the bloom and MHD instabilities can be controlled at higher plasma currents using a higher toroidal field to keep a reasonable beta value, then a higher fusion performance steady state plasma with Q{sub DT} superior to 2.5 should be possible. The alpha heating power of 4.9 MW would lead to a 74% increase in Te. 4 refs., 4 figs., 1 tab.

  9. Progress in theory and simulation of ion cyclotron emission from magnetic confinement fusion plasmas

    Science.gov (United States)

    Dendy, Richard; Chapman, Ben; Chapman, Sandra; Cook, James; Reman, Bernard; McClements, Ken; Carbajal, Leopoldo

    2016-10-01

    Suprathermal ion cyclotron emission (ICE) is detected from all large tokamak and stellarator plasmas. Its frequency spectrum has narrow peaks at sequential cyclotron harmonics of the energetic ion population (fusion-born or neutral beam-injected) at the outer edge of the plasma. ICE was the first collective radiative instability driven by confined fusion-born ions observed in deuterium-tritium plasmas in JET and TFTR, and the magnetoacoustic cyclotron instability is the most likely emission mechanism. Contemporary ICE measurements are taken at very high sampling rates from the LHD stellarator and from the conventional aspect ratio KSTAR tokamak. A correspondingly advanced modelling capability for the ICE emission mechanism has been developed using 1D3V PIC and hybrid-PIC codes, supplemented by analytical theory. These kinetic codes simulate the self-consistent full orbit dynamics of energetic and thermal ions, together with the electric and magnetic fields and the electrons. We report recent progress in theory and simulation that addresses: the scaling of ICE intensity with energetic particle density; the transition between super-Alfvénic and sub-Alfvénic regimes for the collectively radiating particles; and the rapid time evolution that is seen for some ICE measurements. This work was supported in part by the RCUK Energy Programme [Grant Number EP/I501045] and by Euratom.

  10. Simulation of plasma-surface interactions in a fusion reactor by means of QSPA plasma streams: recent results and prospects

    Science.gov (United States)

    Garkusha, I. E.; Aksenov, N. N.; Byrka, O. V.; Makhlaj, V. A.; Herashchenko, S. S.; Malykhin, S. V.; Petrov, Yu V.; Staltsov, V. V.; Surovitskiy, S. V.; Wirtz, M.; Linke, J.; Sadowski, M. J.; Skladnik-Sadowska, E.

    2016-09-01

    This paper is devoted to plasma-surface interaction issues at high heat-loads which are typical for fusion reactors. For the International Thermonuclear Experimental Reactor (ITER), which is now under construction, the knowledge of erosion processes and the behaviour of various constructional materials under extreme conditions is a very critical issue, which will determine a successful realization of the project. The most important plasma-surface interaction (PSI) effects in 3D geometry have been studied using a QSPA Kh-50 powerful quasi-stationary plasma accelerator. Mechanisms of the droplet and dust generation have been investigated in detail. It was found that the droplets emission from castellated surfaces has a threshold character and a cyclic nature. It begins only after a certain number of the irradiating plasma pulses when molten and shifted material is accumulated at the edges of the castellated structure. This new erosion mechanism, connected with the edge effects, results in an increase in the size of the emitted droplets (as compared with those emitted from a flat surface). This mechanism can even induce the ejection of sub-mm particles. A concept of a new-generation QSPA facility, the current status of this device maintenance, and prospects for further experiments are also presented.

  11. Simulating the magnetized liner inertial fusion plasma confinement with smaller-scale experiments [Simulating the MagLIF plasma confinement with smaller-scale experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cuneo, M. E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Herrmann, M. C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sinars, D. B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Slutz, S. A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2012-06-20

    The recently proposed magnetized liner inertial fusion approach to a Z-pinch driven fusion [Slutz et al., Phys. Plasmas17, 056303 (2010)] is based on the use of an axial magnetic field to provide plasma thermal insulation from the walls of the imploding liner. The characteristic plasma transport regimes in the proposed approach cover parameter domains that have not been studied yet in either magnetic confinement or inertial confinement experiments. In this article, an analysis is presented of the scalability of the key physical processes that determine the plasma confinement. The dimensionless scaling parameters are identified and conclusion is drawn that the plasma behavior in scaled-down experiments can correctly represent the full-scale plasma, provided these parameters are approximately the same in two systems. Furthermore, this observation is important in that smaller-scale experiments typically have better diagnostic access and more experiments per year are possible.

  12. Development and evaluation of plasma facing materials for future thermonuclear fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Linke, J.; Pintsuk, G.; Roedig, M.; Schmidt, A.; Thomser, C. [Forschungszentrum Juelich GmbH, EURATOM Association, Juelich (Germany)

    2010-07-01

    More and more attention is directed towards thermonuclear fusion as a possible future energy source. Major advantages of this energy conversion technology are the almost inexhaustible resources and the option to produce energy without CO{sub 2}-emissions. However, in the most advanced field of magnetic plasma confinement a number of technological challenges have to be met. In particular high-temperature resistant and plasma compatible meterials have to be developed and qualified which are able to withstand the extreme environments in a commercial thermonuclear power reactor. The plasma facing materials (PEMs) and components (PFCs) in such fusion devices, i.e. the first wall (FW), the limiters and the divertor, are strongly affected by the plasma wall interaction processes and the applied intense thermal loads during plasma operation. On the one hand, these mechanisms have a strong influence on the plasma performance; on the other hand, they have major impact on the lifetime of the plasma facing armour. Materials for plasma facing components have to fulfill a number of requirements. First of all the materials have to be plasma compatible, i.e. they should exhibit a low atomic number to avoid radiative losses whenever atoms from the wall material will be ionized in the plasma. In addition, the materials must have a high melting point, a high thermal conductivity, and adequate mechanical properties. To select the most suitable material candidates, a comprehensive data base is required which includes all thermo-physical and mechanical properties. In present-day and next step devices the resulting thermal steady state heat loads to the first wall remain below 1 MWm{sup -2}, meanwhile the limiters and the divertor are expected to be exposed to power densities being at least one order of magnitude above the FW-level, i.e. up to 20 MWm{sup -2} for next step tokamaks such as ITER or DEMO. These requirements are responsible for high demands on the selection of qualified PFMs

  13. Kinetic transport in a magnetically confined and flux-constrained fusion plasma; Transport cinetique dans un plasma de fusion magnetique a flux force

    Energy Technology Data Exchange (ETDEWEB)

    Darmet, G

    2007-11-15

    This work deals with the kinetic transport in a fusion plasma magnetically confined and flux-constrained. The author proposes a new interpretation of the dynamics of zonal flows. The model that has been studied is a gyrokinetic model reduced to the transport of trapped ions. The inter-change stability that is generated allows the study of the kinetic transport of trapped ions. This model has a threshold instability and can be simulated over a few tens confining time for either thermal bath constraint or flux constraint. For thermal baths constraint, the simulation shows a metastable state where zonal flows are prevailing while turbulence is non-existent. In the case of a flux-constraint, zonal flows appear and relax by exchanging energy with system's kinetic energy and turbulence energy. The competition between zonal flows and turbulence can be then simulated by a predator-prey model. 2 regimes can be featured out: an improved confining regime where zonal flows dominate transport and a turbulent regime where zonal flows and turbulent transport are of the same magnitude order. We show that flux as well as the Reynolds tensor play an important role in the dynamics of the zonal flows and that the gyrokinetic description is relevant for all plasma regions. (A.C.)

  14. Level crossings, excess times and transient plasma-wall interactions in fusion plasmas

    CERN Document Server

    Theodorsen, Audun

    2016-01-01

    Based on a stochastic model for intermittent fluctuations in the boundary region of magnetically confined plasmas, an expression for the level crossing rate is derived from the joint distribution of the process and its derivative. From this the average time spent by the process above a certain threshold level is obtained. This provides novel predictions of plasma-wall interactions due to transient transport events associated with radial motion of blob-like structures in the scrape-off layer.

  15. Computational Plasma Physics at the Bleeding Edge: Simulating Kinetic Turbulence Dynamics in Fusion Energy Sciences

    Science.gov (United States)

    Tang, William

    2013-04-01

    Advanced computing is generally recognized to be an increasingly vital tool for accelerating progress in scientific research in the 21st Century. The imperative is to translate the combination of the rapid advances in super-computing power together with the emergence of effective new algorithms and computational methodologies to help enable corresponding increases in the physics fidelity and the performance of the scientific codes used to model complex physical systems. If properly validated against experimental measurements and verified with mathematical tests and computational benchmarks, these codes can provide more reliable predictive capability for the behavior of complex systems, including fusion energy relevant high temperature plasmas. The magnetic fusion energy research community has made excellent progress in developing advanced codes for which computer run-time and problem size scale very well with the number of processors on massively parallel supercomputers. A good example is the effective usage of the full power of modern leadership class computational platforms from the terascale to the petascale and beyond to produce nonlinear particle-in-cell simulations which have accelerated progress in understanding the nature of plasma turbulence in magnetically-confined high temperature plasmas. Illustrative results provide great encouragement for being able to include increasingly realistic dynamics in extreme-scale computing campaigns to enable predictive simulations with unprecedented physics fidelity. Some illustrative examples will be presented of the algorithmic progress from the magnetic fusion energy sciences area in dealing with low memory per core extreme scale computing challenges for the current top 3 supercomputers worldwide. These include advanced CPU systems (such as the IBM-Blue-Gene-Q system and the Fujitsu K Machine) as well as the GPU-CPU hybrid system (Titan).

  16. The Evolution of the Gold Bubble in NIF Ignition Gas-Filled Hohlraums

    Science.gov (United States)

    Schneider, Marilyn; MacLaren, Steve; Widmann, Klaus; Meezan, Nathan; Hammer, James; Bell, Perry; Benedetti, Robin; Bradley, David; Callahan, Deborah; Dewald, Eduard; Doeppner, Tilo; Hinkel, Denise; Jones, Oggie; Landen, O. L.; Michel, Pierre; Milovich, Jose; Moody, John; Moore, Alastair

    2015-11-01

    At the National Ignition Facility (NIF), the energy from 192 laser beams is converted to an x-ray drive in a gas-filled gold hohlraum. The x-ray drive heats and implodes a fuel capsule. The ViewFactor platform uses a truncated hohlraum to measure the x-ray drive from the capsule point-of-view. This platform also affords excellent diagnostic views of the hohlraum interior, in particular, of the region in which the outer beams deposit their energy (the ``gold bubble'') Time-resolved and time-integrated images in the hard x-ray range (>3 keV) reveal an 8-fold symmetry in the gold bubble. The Au plasma in the bubble from the eight 50 degree quads expands faster than that from the interleaved 44.5 degree quads. The variation in this structure with laser intensity, with pulse shape and cross beam energy transfer, and comparison to models, will be discussed. This work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  17. The long way to steady state fusion plasmas - the superconducting stellarator device Wendelstein 7-X

    CERN Document Server

    CERN. Geneva

    2016-01-01

    The stable generation of high temperature Hydrogen plasmas (ion and electron temperature in the range 10-20 keV) is the basis for the use of nuclear fusion to generate heat and thereby electric power. The most promising path is to use strong, toroidal, twisted magnetic fields to confine the electrically charged plasma particles in order to avoid heat losses to the cold, solid wall elements. Two magnetic confinement concepts have been proven to be most suitable: (a) the tokamak and (b) the stellarator. The stellarator creates the magnetic field by external coils only, the tokamak by combining the externally created field with the magnetic field generated by a strong current in the plasma. “Wendelstein 7-X” is the name of a large superconducting stellarator that went successfully into operation after 15 years of construction. With 30 m3 plasma volume, 3 T magnetic field on axis, and 10 MW micro wave heating power, Hydrogen plasmas are generated that allow one to establish a scientific basis for the extrapol...

  18. Repetitive tabletop plasma focus to produce a tunable damage factor on materials for fusion reactors

    Science.gov (United States)

    Soto, Leopoldo; Pavez, Cristian; Inestrosa-Izurieta, Maria Jose; Moreno, Jose; Davis, Sergio; Bora, Biswajit; Avaria, Gonzalo; Jain, Jalaj; Altamirano, Luis; Panizo, Miguel; Gonzalez, Raquel; Rivera, Antonio

    2016-10-01

    Future thermonuclear reactors, both magnetic and inertial confinement approaches, need materials capable of withstanding the extreme radiation and heat loads expected from high repetition rate plasma. A damage factor (F = qτ1/2) in the order of 104 (W/cm2) s1/2 is expected. The axial plasma dynamics after the pinch in a tabletop plasma focus of hundred joules, PF-400J, was characterized by means of pulsed optical refractive diagnostics. The energy, interaction time and power flux of the plasma burst interacting with targets was obtained. Results show a high dependence of the damage factor with the distance from the anode top where the sample is located. A tunable damage factor in the range 10- 105(W/cm2) s1/2 can be obtained. At present the PF-400J operating at 0.077 Hz is being used to study the effects of fusion-relevant pulses on material target, including nanostructured materials. A new tabletop device to be operated up to 1Hz including tunable damage factor has been designed and is being constructed, thus thousand cumulative shots on materials could be obtained in few minutes. The scaling of the damage factor for plasma foci operating at different energies is discussed. Supported by CONICYT: PIA ACT-1115, PAI 79130026.

  19. Hydrogen Spectral Line Shape Formation in the SOL of Fusion Reactor Plasmas

    Directory of Open Access Journals (Sweden)

    Valery S. Lisitsa

    2014-05-01

    Full Text Available The problems related to the spectral line-shape formation in the scrape of layer (SOL in fusion reactor plasma for typical observation chords are considered. The SOL plasma is characterized by the relatively low electron density (1012–1013 cm−3 and high temperature (from 10 eV up to 1 keV. The main effects responsible for the line-shape formation in the SOL are Doppler and Zeeman effects. The main problem is a correct modeling of the neutral atom velocity distribution function (VDF. The VDF is determined by a number of atomic processes, namely: molecular dissociation, ionization and charge exchange of neutral atoms on plasma ions, electron excitation accompanied by the charge exchange from atomic excited states, and atom reflection from the wall. All the processes take place step by step during atom motion from the wall to the plasma core. In practice, the largest contribution to the neutral atom radiation emission comes from a thin layer near the wall with typical size 10–20 cm, which is small as compared with the minor radius of modern devices including international test experimental reactor ITER (radius 2 m. The important problem is a strongly non-uniform distribution of plasma parameters (electron and ion densities and temperatures. The distributions vary for different observation chords and ITER operation regimes. In the present report, most attention is paid to the problem of the VDF calculations. The most correct method for solving the problem is an application of the Monte Carlo method for atom motion near the wall. However, the method is sometimes too complicated to be combined with other numerical codes for plasma modeling for various regimes of fusion reactor operation. Thus, it is important to develop simpler methods for neutral atom VDF in space coordinates and velocities. The efficiency of such methods has to be tested via a comparison with the Monte Carlo codes for particular plasma conditions. Here a new simplified method

  20. PREFACE: 30th EPS Conference on Controlled Fusion and Plasma Physics

    Science.gov (United States)

    Koch, R.; Lebedev, S.

    2003-12-01

    The 30th EPS Conference on Controlled Fusion and Plasma Physics took place in St Petersburg, Russian Federation, on 7th--11th July 2003. It was jointly organized by the Ioffe Physico-Technical Institute, the St Petersburg State Polytechnical University and Technical University Applied Physics Ltd, on behalf of the Plasma Physics Division of the European Physical Society (EPS). The members of the local organizing committee were drawn from these institutions: B Kuteev, Chair, Polytechnical University S Lebedev, Vice-Chair, Ioffe Institute A Lebedev, Scientific Secretary, Ioffe Institute V Bakharev, TUAP Ltd V Grigor'yants, Ioffe Institute V Sergeev, Polytechnical University N Zhubr, Ioffe Institute Over the years, the annual conference of the Plasma Physics Division of the European Physical Society has widened its scope. Contributions to the present conference covered widely diversified fields of plasma physics, ranging from magnetic and inertial fusion to low temperature plasmas. Plasma sizes under investigation ranged from tiny to astronomical. The topics covered during the conference were distributed over the following categories: tokamaks, stellarators, high intensity laser produced plasmas and inertial confinement, alternative magnetic confinement, plasma edge physics, plasma heating and current drive, diagnostics, basic plasma physics, astrophysical and geophysical plasmas and low temperature plasmas. The scientific programme and paper selection were the responsibility of the Programme Committee appointed by the Board of the EPS Plasma Physics Division. The committee was composed of: R Koch, Chairman, ERM/KMS Brussels, Belgium E Ascasibar, CIEMAT Madrid, Spain S Atzeni, Università di Roma, Italy G Bonhomme, LPMI Nancy, France C Chiuderi, Università di Firenze, Italy B Kuteev, St Petersburg State Polytechnical,University, Russian Federation M Mauel, Contact person APS-DPP, Columbia University New York, USA R A Pitts, EPFL/CRPP Lausanne, Switzerland R Salomaa

  1. Classical Methods of Statistics With Applications in Fusion-Oriented Plasma Physics

    CERN Document Server

    Kardaun, Otto J W F

    2005-01-01

    Classical Methods of Statistics is a blend of theory and practical statistical methods written for graduate students and researchers interested in applications to plasma physics and its experimental aspects. It can also fruitfully be used by students majoring in probability theory and statistics. In the first part, the mathematical framework and some of the history of the subject are described. Many exercises help readers to understand the underlying concepts. In the second part, two case studies are presented exemplifying discriminant analysis and multivariate profile analysis. The introductions of these case studies outline contextual magnetic plasma fusion research. In the third part, an overview of statistical software is given and, in particular, SAS and S-PLUS are discussed. In the last chapter, several datasets with guided exercises, predominantly from the ASDEX Upgrade tokamak, are included and their physical background is concisely described. The book concludes with a list of essential keyword transl...

  2. Fusion Reactor and Break-Even Experiment Based on Stabilized Liner Compression of Plasma

    Science.gov (United States)

    Turchi, Peter; Frese, Sherry; Frese, Michael

    2016-10-01

    An optimum regime, known as magnetized-target or magneto-inertial fusion (MTF/MIF), requires magnetic fields at megagauss levels, which are attainable by use of dynamic conductors called liners. The stabilized liner compressor (SLC) provides the basis for controlled implosion and re-capture of the liner for reversible energy exchange between liner kinetic energy and the internal energy of a magnetized-plasma target. This exchange requires rotational stabilization of Rayleigh-Taylor modes on the inner surface of the liner and pneumatically driven free-pistons that eliminate such modes at the outer surface. We discuss the implications of the SLC approach for the power reactor, a breakeven experiment, and intermediate experiments to develop the plasma target. Features include the importance of pneumatic drive and the liner-blanket for economic feasibility of MTF/MIF. Supported by ARPA-E ALPHA Program.

  3. Plasma etching to enhance the surface insulating stability of alumina for fusion applications

    Directory of Open Access Journals (Sweden)

    M. Malo

    2016-12-01

    Full Text Available A significant increase in the surface electrical conductivity of alumina, considered one of the most promising insulating materials for numerous applications in fusion devices, has been observed during ion bombardment in vacuum due to oxygen loss by preferential sputtering. Although this is expected to cause serious limitations to insulating components functionality, recent studies showed it is possible to restore the damaged lattice by oxygen reincorporation during thermal treatments in air. These studies also revealed a correlation between conductivity and ion beam induced luminescence, which is being used to monitor surface electrical conductivity degradation and help qualify the post irradiation recovery. Work now carried out for Wesgo alumina considers oxygen implantation and plasma etching as additional methods to improve recovered layer depth and quality. Both conductivity and luminescence results indicate the potential use of plasma etching not only for damage recovery, but also as a pre-treatment to enhance material stability during irradiation.

  4. Robustness of predator-prey models for confinement regime transitions in fusion plasmas

    CERN Document Server

    Zhu, H; Dendy, R O

    2013-01-01

    Energy transport and confinement in tokamak fusion plasmas is usually determined by the coupled nonlinear interactions of small-scale drift turbulence and larger scale coherent nonlinear structures, such as zonal flows, together with free energy sources such as temperature gradients. Zero-dimensional models, designed to embody plausible physical narratives for these interactions, can help identify the origin of enhanced energy confinement and of transitions between confinement regimes. A prime zero-dimensional paradigm is predator-prey or Lotka-Volterra. Here we extend a successful three-variable (temperature gradient; microturbulence level; one class of coherent structure) model in this genre [M A Malkov and P H Diamond, Phys. Plasmas 16, 012504 (2009)], by adding a fourth variable representing a second class of coherent structure. This requires a fourth coupled nonlinear ordinary differential equation. We investigate the degree of invariance of the phenomenology generated by the model of Malkov and Diamond,...

  5. Velocity-space tomography of fusion plasmas by collective Thomson scattering of gyrotron radiation

    DEFF Research Database (Denmark)

    Salewski, Mirko; Jacobsen, A.S.; Jensen, Thomas;

    2016-01-01

    We propose a diagnostic capable of measuring 2D fast-ion velocity distribution functions 푓2퐷푣 in the MeV-range in magnetized fusion plasmas. Today velocity-space tomography based on fast-ion D훼 spectroscopy is regularly used to measure 푓2퐷푣 for ion energies below 100 keV. Unfortunately, the signal......-tonoise ratio becomes fairly low for MeV-range ions. Ions at any energy can be detected well by collective Thomson scattering of mm-wave radiation from a high-power gyrotron. We demonstrate how collective Thomson scattering can be used to measure 푓2퐷푣 in the MeV-range in reactor relevant plasmas...

  6. The structure, properties and performance of plasma-sprayed beryllium for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Castro, R.G.; Stanek, P.W.; Elliott, K.E. [and others

    1995-09-01

    Plasma-spray technology is under investigation as a method for producing high thermal conductivity beryllium coatings for use in magnetic fusion applications. Recent investigations have focused on optimizing the plasma-spray process for depositing beryllium coatings on damaged beryllium surfaces. Of particular interest has been optimizing the processing parameters to maximize the through-thickness thermal conductivity of the beryllium coatings. Experimental results will be reported on the use of secondary H{sub 2} gas additions to improve the melting of the beryllium powder and transferred-arc cleaning to improve the bonding between the beryllium coatings and the underlying surface. Information will also be presented on thermal fatigue tests which were done on beryllium coated ISX-B beryllium limiter tiles using 10 sec cycle times with 60 sec cooldowns and an International Thermonuclear Experimental Reactor (ITER) relevant divertor heat flux slightly in excess of 5 MW/m{sup 2}.

  7. Diagnosing laser-preheated magnetized plasmas relevant to magnetized liner inertial fusion

    Science.gov (United States)

    Harvey-Thompson, A. J.; Sefkow, A. B.; Nagayama, T. N.; Wei, M. S.; Campbell, E. M.; Fiksel, G.; Chang, P.-Y.; Davies, J. R.; Barnak, D. H.; Glebov, V. Y.; Fitzsimmons, P.; Fooks, J.; Blue, B. E.

    2015-12-01

    We present a platform on the OMEGA EP Laser Facility that creates and diagnoses the conditions present during the preheat stage of the MAGnetized Liner Inertial Fusion (MagLIF) concept. Experiments were conducted using 9 kJ of 3ω (355 nm) light to heat an underdense deuterium gas (electron density: 2.5 ×1020 cm-3=0.025 of critical density) magnetized with a 10 T axial field. Results show that the deuterium plasma reached a peak electron temperature of 670 ± 140 eV, diagnosed using streaked spectroscopy of an argon dopant. The results demonstrate that plasmas relevant to the preheat stage of MagLIF can be produced at multiple laser facilities, thereby enabling more rapid progress in understanding magnetized preheat. Results are compared with magneto-radiation-hydrodynamics simulations, and plans for future experiments are described.

  8. Plasma Wall Interaction Phenomena on Tungsten Armour Materials for Fusion Applications

    Energy Technology Data Exchange (ETDEWEB)

    Uytdenhouwen, I. [SCK.CEN - The Belgian Nuclear Research Centre, Institute for Nuclear Materials Science, Boeretang 200, 2400 Mol (Belgium); Forschungszentrum Juelich GmbH, EURATOM-association, D-52425 Juelich (Germany); Department of Applied Physics, Ghent University, Rozier 44, 9000 Ghent (Belgium); Massaut, V. [Department of Applied Physics, Ghent University, Rozier 44, 9000 Ghent (Belgium); Linke, J. [Forschungszentrum Juelich GmbH, EURATOM-association, D-52425 Juelich (Germany); Van Oost, G. [Department of Applied Physics, Ghent University, Rozier 44, 9000 Ghent (Belgium)

    2008-07-01

    One of the most attractive future complements to present energy sources is nuclear fusion. A large progress was made throughout the last decade from both the physical as the technological area leading to the construction of the ITER machine. One of the key issues that recently received a large interest at international level is focused on the Plasma Wall Interaction (PWI). One of the promising Plasma Facing Materials (PFM) are Tungsten (W) and Tungsten alloys. However, despite the worldwide use and industrial availability of W, the database of physical and mechanical properties is very limited. Especially after fusion relevant neutron irradiation and PWI phenomena, most of the properties are still unknown. The plasma fuel consists out of deuterium (D) and tritium (T). Tritium is radio-active and therefore an issue from the safety point of view. During steady-state plasma operation of future fusion power plants, the PFM need to extract a power density of {approx}10-20 MW/m{sup 2}. On top of this heat, transient events will deposit an additional non-negligible amount of energy (Disruptions, Vertical Displacement Events, Edge Localized Modes) during short durations. These severe heat loads cause cracking and even melting of the surface resulting in a reduced lifetime and the creation of dust. A contribution to the understanding of cracking phenomena under the severe thermal loads is described as well as the properties degradation under neutron irradiation. Several W grades were irradiated in the BR2 reactor (SCK.CEN) and the thermal loads were simulated with the electron-beam facility JUDITH (FZJ). Since knowledge should be gained about the Tritium retention in the PFM for safety and licensing reasons, a unique test facility at SCK.CEN is being set-up. The plasmatron VISION-I will simulate steady state plasmas for Tritium retention studies. The formation of surface cracks and dust, the initial porosity, neutron induced traps, re-deposited material - change the Tritium

  9. Spectroscopic Studies of Atomic and Molecular Processes in the Edge Region of Magnetically Confined Fusion Plasmas

    Science.gov (United States)

    Hey, J. D.; Brezinsek, S.; Mertens, Ph.; Unterberg, B.

    2006-12-01

    Edge plasma studies are of vital importance for understanding plasma-wall interactions in magnetically confined fusion devices. These interactions determine the transport of neutrals into the plasma, and the properties of the plasma discharge. This presentation deals with optical spectroscopic studies of the plasma boundary, and their rôle in elucidating the prevailing physical conditions. Recorded spectra are of four types: emission spectra of ions and atoms, produced by electron impact excitation and by charge-exchange recombination, atomic spectra arising from electron impact-induced molecular dissociation and ionisation, visible spectra of molecular hydrogen and its isotopic combinations, and laser-induced fluorescence (LIF) spectra. The atomic spectra are strongly influenced by the confining magnetic field (Zeeman and Paschen-Back effects), which produces characteristic features useful for species identification, temperature determination by Doppler broadening, and studies of chemical and physical sputtering. Detailed analysis of the Zeeman components in both optical and LIF spectra shows that atomic hydrogen is produced in various velocity classes, some related to the relevant molecular Franck-Condon energies. The latter reflect the dominant electron collision processes responsible for production of atoms from molecules. This assignment has been verified by gas-puffing experiments through special test limiters. The higher-energy flanks of hydrogen line profiles probably also show the influence of charge-exchange reactions with molecular ions accelerated in the plasma sheath (`scrape-off layer') separating limiter surfaces from the edge plasma, in analogy to acceleration in the cathode-fall region of gas discharges. While electron collisions play a vital rôle in generating the spectra, ion collisions with excited atomic radiators act through re-distribution of population among the atomic fine-structure sublevels, and momentum transfer to the atomic nuclei

  10. The size and structure of the laser entrance hole in gas-filled hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M. B., E-mail: schneider5@llnl.gov; MacLaren, S. A.; Widmann, K.; Meezan, N. B.; Hammer, J. H.; Yoxall, B. E.; Bell, P. M.; Benedetti, L. R.; Bradley, D. K.; Callahan, D. A.; Dewald, E. L.; Döppner, T.; Eder, D. C.; Edwards, M. J.; Hinkel, D. E.; Hsing, W. W.; Kervin, M. L.; Landen, O. L.; Lindl, J. D.; May, M. J. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); and others

    2015-12-15

    At the National Ignition Facility, a thermal X-ray drive is created by laser energy from 192 beams heating the inside walls of a gold cylinder called a “hohlraum.” The x-ray drive heats and implodes a fuel capsule. The laser beams enter the hohlraum via laser entrance holes (LEHs) at each end. The LEH radius decreases as heated plasma from the LEH material blows radially inward but this is largely balanced by hot plasma from the high-intensity region in the center of the LEH pushing radially outward. The x-ray drive on the capsule is deduced by measuring the time evolution and spectra of the x-radiation coming out of the LEH and correcting for geometry and for the radius of the LEH. Previously, the LEH radius was measured using time-integrated images in an x-ray band of 3–5 keV (outside the thermal x-ray region). For gas-filled hohlraums, the measurements showed that the LEH radius is larger than that predicted by the standard High Flux radiation-hydrodynamic model by about 10%. A new platform using a truncated hohlraum (“ViewFactor hohlraum”) is described, which allows time-resolved measurements of the LEH radius at thermal x-ray energies from two views, from outside the hohlraum and from inside the hohlraum. These measurements show that the LEH radius closes during the low power part of the pulse but opens up again at peak power. The LEH radius at peak power is larger than that predicted by the models by about 15%–20% and does not change very much with time. In addition, time-resolved images in a >4 keV (non-thermal) x-ray band show a ring of hot, optically thin gold plasma just inside the optically thick LEH plasma. The structure of this plasma varies with time and with Cross Beam Energy Transfer.

  11. Noise temperature improvement for magnetic fusion plasma millimeter wave imaging systems

    Energy Technology Data Exchange (ETDEWEB)

    Lai, J.; Domier, C. W.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616 (United States)

    2014-03-15

    Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas [B. Tobias et al., Plasma Fusion Res. 6, 2106042 (2011)]. Of particular importance have been microwave electron cyclotron emission imaging and microwave imaging reflectometry systems for imaging T{sub e} and n{sub e} fluctuations. These instruments have employed heterodyne receiver arrays with Schottky diode mixer elements directly connected to individual antennas. Consequently, the noise temperature has been strongly determined by the conversion loss with typical noise temperatures of ∼60 000 K. However, this can be significantly improved by making use of recent advances in Monolithic Microwave Integrated Circuit chip low noise amplifiers to insert a pre-amplifier in front of the Schottky diode mixer element. In a proof-of-principle design at V-Band (50–75 GHz), significant improvement of noise temperature from the current 60 000 K to measured 4000 K has been obtained.

  12. Z-Pinch Generated X-Rays in Static-Wall Hohlraum Geometry Demonstrate Potential for Indirect-Drive ICF Studies

    Energy Technology Data Exchange (ETDEWEB)

    BOWERS,RICHARD; CHANDLER,GORDON A.; HEBRON,DAVID E.; LEEPER,RAMON J.; MATUSLKA,WALTER; MOCK,RAYMOND CECIL; NASH,THOMAS J.; OLSON,CRAIG L.; PETERSON,BOB; PETERSON,DARRELL; RUGGLES,LAURENCE E.; SANFORD,THOMAS W. L.; SIMPSON,WALTER W.; STRUVE,KENNETH W.; VESEY,ROGER A.

    1999-11-01

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch magnet on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry. A 2-{micro}m-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm{sup 3} CH, for example, produces foot-pulse conditions of {approx}85 eV for a duration of {approx}10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm{sup 3} CH generates first-step-pulse conditions of {approx}122 eV for a duration of a few ns. Alternatively, reducing the hohlraum size (to 4-mm diameter by 4-mm length) with the latter target has increased the peak temperature to {approx}150 eV, which is characteristic of a second-step-pulse temperature. In general, the temperature T of these x-ray driven hohlraums is in agreement with the Planckian relation T{approx}(P/A){sup 1/4}. P is the measured x-ray input power and A is the surface area of the hohlraum. Fully-integrated 2-D radiation-hydrodynamic simulations of the z pinch and subsequent hohlraum heating show plasma densities within the useful volume of the hohlraums to be on the order of air or less.

  13. Z-Pinch Generated X-Rays in Static-Wall Hohlraum Geometry Demonstrate Potential for Indirect-Drive ICF Studies

    Energy Technology Data Exchange (ETDEWEB)

    Sandord, T.W.L.; Olson, R.E.; Chandler, G.A.; Hebron, D.E.; Mock, R.C.; Leeper, R.J.; Nash, T.J.; Ruggles, L.E.; Simpson, W.W.; Struve, K.W.; Vesey, R.A.; Bowers, R.L.; Matuska, W.; Peterson, D.L.; Peterson, R.R.

    1999-08-25

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch target on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry. A 2-{micro}m-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm{sup 3} CH, for example, produces foot-pulse conditions of {minus}85 eV for a duration of {approximately} 10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm{sup 3} CH generates first-step-pulse conditions of {approximately} 122 eV for a duration of a few ns. Alternatively, reducing the hohlraum size (to 4-mm diameter by 4-mm length) with the latter target has increased the peak temperature to {approximately} 150 eV, which is characteristic of a second-step-pulse temperature. In general, the temperature T of these x-ray driven hohlraums is in agreement with the Planckian relation (T-(P/A){sup 1/4}). P is the measured x-ray input power and A is the surface area of the hohlraum. Fully-integrated 2-D radiation-hydrodynamic simulations of the z pinch and subsequent hohlraum heating show plasma densities within the useful volume of the hohlraums to be on the order of air or less.

  14. Evaluation of the operational parameters for NBI-driven fusion in low-gain tokamaks with two-component plasma

    Science.gov (United States)

    Chirkov, A. Yu.

    2015-09-01

    Low gain (Q ~ 1) fusion plasma systems are of interest for concepts of fusion-fission hybrid reactors. Operational regimes of large modern tokamaks are close to Q  ≈  1. Therefore, they can be considered as prototypes of neutron sources for fusion-fission hybrids. Powerful neutral beam injection (NBI) can support the essential population of fast particles compared with the Maxwellial population. In such two-component plasma, fusion reaction rate is higher than for Maxwellian plasma. Increased reaction rate allows the development of relatively small-size and relatively inexpensive neutron sources. Possible operating regimes of the NBI-heated tokamak neutron source are discussed. In a relatively compact device, the predictions of physics of two-component fusion plasma have some volatility that causes taking into account variations of the operational parameters. Consequent parameter ranges are studied. The feasibility of regimes with Q  ≈  1 is shown for the relatively small and low-power system. The effect of NBI fraction in total heating power is analyzed.

  15. Automatically Identifying Fusion Events between GLUT4 Storage Vesicles and the Plasma Membrane in TIRF Microscopy Image Sequences

    Directory of Open Access Journals (Sweden)

    Jian Wu

    2015-01-01

    Full Text Available Quantitative analysis of the dynamic behavior about membrane-bound secretory vesicles has proven to be important in biological research. This paper proposes a novel approach to automatically identify the elusive fusion events between VAMP2-pHluorin labeled GLUT4 storage vesicles (GSVs and the plasma membrane. The differentiation is implemented to detect the initiation of fusion events by modified forward subtraction of consecutive frames in the TIRFM image sequence. Spatially connected pixels in difference images brighter than a specified adaptive threshold are grouped into a distinct fusion spot. The vesicles are located at the intensity-weighted centroid of their fusion spots. To reveal the true in vivo nature of a fusion event, 2D Gaussian fitting for the fusion spot is used to derive the intensity-weighted centroid and the spot size during the fusion process. The fusion event and its termination can be determined according to the change of spot size. The method is evaluated on real experiment data with ground truth annotated by expert cell biologists. The evaluation results show that it can achieve relatively high accuracy comparing favorably to the manual analysis, yet at a small fraction of time.

  16. Robustness of predator-prey models for confinement regime transitions in fusion plasmas

    Science.gov (United States)

    Zhu, H.; Chapman, S. C.; Dendy, R. O.

    2013-04-01

    Energy transport and confinement in tokamak fusion plasmas is usually determined by the coupled nonlinear interactions of small-scale drift turbulence and larger scale coherent nonlinear structures, such as zonal flows, together with free energy sources such as temperature gradients. Zero-dimensional models, designed to embody plausible physical narratives for these interactions, can help to identify the origin of enhanced energy confinement and of transitions between confinement regimes. A prime zero-dimensional paradigm is predator-prey or Lotka-Volterra. Here, we extend a successful three-variable (temperature gradient; microturbulence level; one class of coherent structure) model in this genre [M. A. Malkov and P. H. Diamond, Phys. Plasmas 16, 012504 (2009)], by adding a fourth variable representing a second class of coherent structure. This requires a fourth coupled nonlinear ordinary differential equation. We investigate the degree of invariance of the phenomenology generated by the model of Malkov and Diamond, given this additional physics. We study and compare the long-time behaviour of the three-equation and four-equation systems, their evolution towards the final state, and their attractive fixed points and limit cycles. We explore the sensitivity of paths to attractors. It is found that, for example, an attractive fixed point of the three-equation system can become a limit cycle of the four-equation system. Addressing these questions which we together refer to as "robustness" for convenience is particularly important for models which, as here, generate sharp transitions in the values of system variables which may replicate some key features of confinement transitions. Our results help to establish the robustness of the zero-dimensional model approach to capturing observed confinement phenomenology in tokamak fusion plasmas.

  17. Robustness of predator-prey models for confinement regime transitions in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, H. [Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom); Chapman, S. C. [Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom); Department of Mathematics and Statistics, University of Tromso (Norway); Dendy, R. O. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2013-04-15

    Energy transport and confinement in tokamak fusion plasmas is usually determined by the coupled nonlinear interactions of small-scale drift turbulence and larger scale coherent nonlinear structures, such as zonal flows, together with free energy sources such as temperature gradients. Zero-dimensional models, designed to embody plausible physical narratives for these interactions, can help to identify the origin of enhanced energy confinement and of transitions between confinement regimes. A prime zero-dimensional paradigm is predator-prey or Lotka-Volterra. Here, we extend a successful three-variable (temperature gradient; microturbulence level; one class of coherent structure) model in this genre [M. A. Malkov and P. H. Diamond, Phys. Plasmas 16, 012504 (2009)], by adding a fourth variable representing a second class of coherent structure. This requires a fourth coupled nonlinear ordinary differential equation. We investigate the degree of invariance of the phenomenology generated by the model of Malkov and Diamond, given this additional physics. We study and compare the long-time behaviour of the three-equation and four-equation systems, their evolution towards the final state, and their attractive fixed points and limit cycles. We explore the sensitivity of paths to attractors. It is found that, for example, an attractive fixed point of the three-equation system can become a limit cycle of the four-equation system. Addressing these questions which we together refer to as 'robustness' for convenience is particularly important for models which, as here, generate sharp transitions in the values of system variables which may replicate some key features of confinement transitions. Our results help to establish the robustness of the zero-dimensional model approach to capturing observed confinement phenomenology in tokamak fusion plasmas.

  18. Synthetic aperture microwave imaging with active probing for fusion plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, Vladimir F.; Freethy, Simon J.; Huang, Billy K. [EURATOM/CCFE Fusion Association, Culham, Abingdon, Oxon, 0X14 3DB (United Kingdom); Vann, Roddy G. L. [York Plasma Institute, Dept. of Physics, University of York, York YO10 5DD (United Kingdom)

    2014-08-21

    A Synthetic Aperture Microwave Imaging (SAMI) system has been designed and built to obtain 2-D images at several frequencies from fusion plasmas. SAMI uses a phased array of linearly polarised antennas. The array configuration has been optimised to achieve maximum synthetic aperture beam efficiency. The signals received by antennas are down-converted to the intermediate frequency range and then recorded in a full vector form. Full vector signals allow beam focusing and image reconstruction in both real time and a post-processing mode. SAMI can scan over 16 pre-programmed frequencies in the range of 10-35GHz with a switching time of 300ns. The system operates in 2 different modes simultaneously: both a 'passive' imaging of plasma emission and also an 'active' imaging of the back-scattered signal of the radiation launched by one of the antennas from the same array. This second mode is similar to so-called Doppler backscattering (DBS) reflectometry with 2-D resolution of the propagation velocity of turbulent structures. Both modes of operation show good performance in fusion plasma experiments on Mega Amp Spherical Tokamak (MAST). We have obtained the first ever 2-D images of BXO mode conversion windows. With active probing, first ever turbulence velocity maps have been obtained. We present an overview of the diagnostic and discuss recent results. In contrast to quasi-optical microwave imaging systems SAMI requires neither big aperture viewing ports nor large 2-D detector arrays to achieve the desired imaging resolution. The number of effective 'pixels' of the synthesized image is proportional to the number of receiving antennas squared. Thus only a small number of optimised antennas is sufficient for the majority of applications. Possible implementation of SAMI on ITERand DEMO is discussed.

  19. Synthetic aperture microwave imaging with active probing for fusion plasma diagnostics

    Science.gov (United States)

    Shevchenko, Vladimir F.; Freethy, Simon J.; Huang, Billy K.; Vann, Roddy G. L.

    2014-08-01

    A Synthetic Aperture Microwave Imaging (SAMI) system has been designed and built to obtain 2-D images at several frequencies from fusion plasmas. SAMI uses a phased array of linearly polarised antennas. The array configuration has been optimised to achieve maximum synthetic aperture beam efficiency. The signals received by antennas are down-converted to the intermediate frequency range and then recorded in a full vector form. Full vector signals allow beam focusing and image reconstruction in both real time and a post-processing mode. SAMI can scan over 16 pre-programmed frequencies in the range of 10-35GHz with a switching time of 300ns. The system operates in 2 different modes simultaneously: both a 'passive' imaging of plasma emission and also an 'active' imaging of the back-scattered signal of the radiation launched by one of the antennas from the same array. This second mode is similar to so-called Doppler backscattering (DBS) reflectometry with 2-D resolution of the propagation velocity of turbulent structures. Both modes of operation show good performance in fusion plasma experiments on Mega Amp Spherical Tokamak (MAST). We have obtained the first ever 2-D images of BXO mode conversion windows. With active probing, first ever turbulence velocity maps have been obtained. We present an overview of the diagnostic and discuss recent results. In contrast to quasi-optical microwave imaging systems SAMI requires neither big aperture viewing ports nor large 2-D detector arrays to achieve the desired imaging resolution. The number of effective 'pixels' of the synthesized image is proportional to the number of receiving antennas squared. Thus only a small number of optimised antennas is sufficient for the majority of applications. Possible implementation of SAMI on ITERand DEMO is discussed.

  20. Convergent ablation measurements of plastic ablators in gas-filled rugby hohlraums on OMEGA

    Science.gov (United States)

    Casner, A.; Jalinaud, T.; Masse, L.; Galmiche, D.

    2015-10-01

    Indirect-drive implosions experiments were conducted on the Omega Laser Facility to test the performance of uniformly doped plastic ablators for Inertial Confinement Fusion. The first convergent ablation measurements in gas-filled rugby hohlraums are reported. Ignition relevant limb velocities in the range from 150 to 300 μm .n s-1 have been reached by varying the laser drive energy and the initial capsule aspect ratio. The measured capsule trajectory and implosion velocity are in good agreement with 2D integrated simulations and a zero-dimensional modeling of the implosions. We demonstrate experimentally the scaling law for the maximum implosion velocity predicted by the improved rocket model [Y. Saillard, Nucl. Fusion 46, 1017 (2006)] in the high-ablation regime case.

  1. Experimental characterization of NIF hohlraum emission in the Rayleigh-Jeans limit (1 eV to 5 eV)

    Science.gov (United States)

    Moody, J. D.; Goyon, C. E.; Ross, J. S.; Swadling, G. F.; Moore, A. S.; Baker, K. L.; Thomas, C. A.; Schneider, M. B.; Landen, O. L.; Michel, P. A.; Strozzi, D. J.; Divol, L.; Widmann, K.

    2016-10-01

    We use several measurements to estimate NIF hohlraum emission in the Rayleigh-Jeans limit where hν collected by an optical photodiode, optical emission emitted from the laser-entrance hole in the 4 eV range, and various other optical measurements. These measurements can help quantify the laser-plasma interaction processes occurring in the hohlraum and may provide insight into the atomic physics of the Au wall at long wavelength. We describe our findings and discuss interpretations. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. Approach to Developing Predictive Capability for Hohlraum Drive and Symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-22

    Currently, we do not have the ability to predict the hohlraum drive and symmetry without requiring ad hoc adjustments to physics models. This document describes a plan for code improvements and focused physics validation experiments.

  3. Role of a continuous MHD dynamo in the formation of 3D equilibria in fusion plasmas

    Science.gov (United States)

    Piovesan, P.; Bonfiglio, D.; Cianciosa, M.; Luce, T. C.; Taylor, N. Z.; Terranova, D.; Turco, F.; Wilcox, R. S.; Wingen, A.; Cappello, S.; Chrystal, C.; Escande, D. F.; Holcomb, C. T.; Marrelli, L.; Paz-Soldan, C.; Piron, L.; Predebon, I.; Zaniol, B.; DIII-D, The; RFX-Mod Teams

    2017-07-01

    Stationary 3D equilibria can form in fusion plasmas via saturation of magnetohydrodynamic (MHD) instabilities or stimulated by external 3D fields. In these cases the current profile is anomalously broad due to magnetic flux pumping produced by the MHD modes. Flux pumping plays an important role in hybrid tokamak plasmas, maintaining the minimum safety factor above unity and thus removing sawteeth. It also enables steady-state hybrid operation, by redistributing non-inductive current driven near the center by electron cyclotron waves. A validated flux pumping model is not yet available, but it would be necessary to extrapolate hybrid operation to future devices. In this work flux pumping physics is investigated for helical core equilibria stimulated by external 3D fields in DIII-D hybrid plasmas. We show that flux pumping can be produced in a continuous way by an MHD dynamo emf. The same effect maintains helical equilibria in reversed-field pinch (RFP) plasmas. The effective MHD dynamo loop voltage is calculated for experimental 3D equilibrium reconstructions, by balancing Ohm’s law over helical flux surfaces, and is consistent with the expected current redistribution. Similar results are also obtained with more sophisticated nonlinear MHD simulations. The same modelling approach is applied to helical RFP states forming spontaneously in RFX-mod as the plasma current is raised above 0.8-1 MA. This comparison allows to identify the underlying physics common to tokamak and RFP: a helical core displacement modulates parallel current density along flux tubes, which requires a helical electrostatic potential to build up, giving rise to a helical MHD dynamo flow.

  4. Laser-plasma interaction in the context of inertial fusion: experiments and modeling

    Science.gov (United States)

    Labaune, C.; Lewis, K.; Bandulet, H.; Depierreux, S.; Hüller, S.; Masson-Laborde, P. E.; Pesme, D.; Loiseau, P.

    2007-08-01

    Many nonlinear processes may affect the laser beam propagation and the laser energy deposition in the underdense plasma surrounding the pellet. These processes, associated with anomalous and nonlinear absorption mechanisms, are fundamental issues in the context of Inertial Confinement Fusion. The work presented in this article refers to laser-plasma interaction experiments which were conducted under well-controlled conditions, and to their theoretical and numerical modeling. Thanks to important diagnostics improvements, the plasma and laser parameters were sufficiently characterized in these experiments to make it possible to carry out numerical simulations modeling the laser plasma interaction in which the hydrodynamics conditions were very close to the experimental ones. Two sets of experiments were carried out with the LULI 2000 and the six beam LULI laser facilities. In the first series of experiments, the interaction between two single hot spots was studied as a function of their distance, intensity and light polarization. In the second series, the intensity distribution of stimulated Brillouin scattering (SBS) inside the plasma was studied by means of a new temporally resolved imaging system. Two-dimensional (2D) simulations were carried out with our code Harmony2D in order to model these experiments. For both series of experiments, the numerical results show a very good agreement with the experimental ones for what concerns the main SBS features, namely the spatial and temporal behavior of the SBS-driven acoustic waves, as well as the average SBS reflectivities. Thus, these well diagnosed experiments, carried out with well defined conditions, make it possible to benchmark our theoretical and numerical modelings and, hence, to improve our predictive capabilities for future experiments.

  5. Membrane fusion

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    At Stanford University, Boxer lab, I worked on membrane fusion of small unilamellar lipid vesicles to flat membranes tethered to glass surfaces. This geometry closely resembles biological systems in which liposomes fuse to plasma membranes. The fusion mechanism was studied using DNA zippering...... between complementary strands linked to the two apposing membranes closely mimicking the zippering mechanism of SNARE fusion complexes....

  6. Laser-Plasma Interactions on NIKE and the Fusion Test Facility

    Science.gov (United States)

    Phillips, Lee; Weaver, James

    2008-11-01

    Recent proposed designs for a Fusion Test Facility (FTF) (Obenchain et al., Phys. Plasmas 13 056320 (2006)) for direct-drive ICF targets for energy applications involve high implosion velocities combined with higher laser irradiances. The use of high irradiances increases the likelihood of deleterious laser plasma instabilities (LPI) but the proposed use of a 248 nm KrF laser to drive these targets is expected to minimize the LPI risk. We examine, using simulation results from NRL's FAST hydrocode, the proposed operational regimes of the FTF in relation to the thresholds for the SRS, SBS, and 2-plasmon instabilities. Simulations are also used to help design and interpret ongoing experiments being conducted at NRL's NIKE facility for the purpose of generating and studying LPI. Target geometries and laser pulseshapes were devised in order to create plasma conditions with long scalelengths and low electron temperatures that allow the growth of parametric instabilities. These simulations include the effects of finite beam angles through the use of raytracing.

  7. Laser-generated magnetic fields in quasi-hohlraum geometries

    Science.gov (United States)

    Pollock, Bradley; Turnbull, David; Ross, Steven; Hazi, Andrew; Ralph, Joseph; Lepape, Sebastian; Froula, Dustin; Haberberger, Dan; Moody, John

    2014-10-01

    Laser-generated magnetic fields of 10--40 T have been produced with 100--4000 J laser drives at Omega EP and Titan. The fields are generated using the technique described by Daido et al. [Phys. Rev. Lett. 56, 846 (1986)], which works by directing a laser through a hole in one plate to strike a second plate. Hot electrons generated in the laser-produced plasma on the second plate collect on the first plate. A strap connects the two plates allowing a current of 10 s of kA to flow and generate a solenoidal magnetic field. The magnetic field is characterized using Faraday rotation, b-dot probes, and proton radiography. Further experiments to study the effect of the magnetic field on hohlraum performance are currently scheduled for Omega. This work was performed under the auspices of the United States Department of Energy by the Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA-27344.

  8. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic.

    Science.gov (United States)

    Swadling, G F; Ross, J S; Datte, P; Moody, J; Divol, L; Jones, O; Landen, O

    2016-11-01

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ∼8 J cm(-2). This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 10(19) cm(-2) Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

  9. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic

    Science.gov (United States)

    Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O.

    2016-11-01

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ˜8 J cm-2. This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 1019 cm-2 Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

  10. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause “blanking” (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ∼8 J cm{sup −2}. This is significantly above the expected threshold for the onset of “blanking” effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate “blanking.” Estimates suggest that an areal density of 10{sup 19} cm{sup −2} Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

  11. Degenerate Bogdanov-Takens bifurcations in a one-dimensional transport model of a fusion plasma

    Science.gov (United States)

    de Blank, H. J.; Kuznetsov, Yu. A.; Pekkér, M. J.; Veldman, D. W. M.

    2016-09-01

    Experiments in tokamaks (nuclear fusion reactors) have shown two modes of operation: L-mode and H-mode. Transitions between these two modes have been observed in three types: sharp, smooth and oscillatory. The same modes of operation and transitions between them have been observed in simplified transport models of the fusion plasma in one spatial dimension. We study the dynamics in such a one-dimensional transport model by numerical continuation techniques. To this end the MATLAB package CL_MATCONTL was extended with the continuation of (codimension-2) Bogdanov-Takens bifurcations in three parameters using subspace reduction techniques. During the continuation of (codimension-2) Bogdanov-Takens bifurcations in 3 parameters, generically degenerate Bogdanov-Takens bifurcations of codimension-3 are detected. However, when these techniques are applied to the transport model, we detect a degenerate Bogdanov-Takens bifurcation of codimension 4. The nearby 1- and 2-parameter slices are in agreement with the presence of this codimension-4 degenerate Bogdanov-Takens bifurcation, and all three types of L-H transitions can be recognized in these slices. The same codimension-4 situation is observed under variation of the additional parameters in the model, and under some modifications of the model.

  12. Nonlinear dynamics of phase space zonal structures and energetic particle physics in fusion plasmas

    CERN Document Server

    Zonca, Fulvio; Briguglio, Sergio; Fogaccia, Giuliana; Vlad, Gregorio; Wang, Xin

    2014-01-01

    A general theoretical framework for investigating nonlinear dynamics of phase space zonal structures is presented in this work. It is then, more specifically, applied to the limit where the nonlinear evolution time scale is smaller or comparable to the wave-particle trapping period. In this limit, both theoretical and numerical simulation studies show that non-adiabatic frequency chirping and phase locking could lead to secular resonant particle transport on meso- or macro-scales. The interplay between mode structures and resonant particles then provides the crucial ingredient to properly understand and analyze the nonlinear dynamics of Alfv\\'en wave instabilities excited by non-perturbative energetic particles in burning fusion plasmas. Analogies with autoresonance in nonlinear dynamics and with superradiance in free electron lasers are also briefly discussed.

  13. An accurate automated technique for quasi-optics measurement of the microwave diagnostics for fusion plasma

    Science.gov (United States)

    Hu, Jianqiang; Liu, Ahdi; Zhou, Chu; Zhang, Xiaohui; Wang, Mingyuan; Zhang, Jin; Feng, Xi; Li, Hong; Xie, Jinlin; Liu, Wandong; Yu, Changxuan

    2017-08-01

    A new integrated technique for fast and accurate measurement of the quasi-optics, especially for the microwave/millimeter wave diagnostic systems of fusion plasma, has been developed. Using the LabVIEW-based comprehensive scanning system, we can realize not only automatic but also fast and accurate measurement, which will help to eliminate the effects of temperature drift and standing wave/multi-reflection. With the Matlab-based asymmetric two-dimensional Gaussian fitting method, all the desired parameters of the microwave beam can be obtained. This technique can be used in the design and testing of microwave diagnostic systems such as reflectometers and the electron cyclotron emission imaging diagnostic systems of the Experimental Advanced Superconducting Tokamak.

  14. Proceedings of the US-Japan workshop and the satellite meeting of ITC-9 on physics of high beta plasma confinement in innovative fusion system

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Seiichi; Yoshimura, Satoru [eds.

    1999-04-01

    The US-Japan Workshop on Physics of High Beta Plasma Confinement in Innovative Fusion System was held jointly with the Satellite Meeting of ITC-9 at National Institute for Fusion Science (NIFS), Toki-city during December 14-15, 1998. This proceedings book includes the papers of the talks given at the workshop. These include: Theoretical analysis on the stability of field reversed configuration (FRC) plasmas; Theory and Modeling of high {beta} plasmas; Recent progressive experiments in high {beta} systems; Formation of high {beta} plasmas using merging phenomenon; Theory and Modeling of a FRC Fusion Reactor. The 15 papers are indexed individually. (J.P.N.)

  15. Characterization of the axial plasma shock in a table top plasma focus after the pinch and its possible application to testing materials for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Soto, Leopoldo, E-mail: lsoto@cchen.cl; Pavez, Cristian; Moreno, José [Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago (Chile); Centro de Investigación y Aplicaciones en Física de Plasmas y Potencia Pulsada, P" 4, Santiago-Talca (Chile); Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, República 220, Santiago (Chile); Inestrosa-Izurieta, María José [Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago (Chile); Centro de Investigación y Aplicaciones en Física de Plasmas y Potencia Pulsada, P" 4, Santiago-Talca (Chile); Veloso, Felipe [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago (Chile); Gutiérrez, Gonzalo [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Vergara, Julio [Facultad de Ingeniería, Pontificia Universidad Católica de Chile, Santiago (Chile); Clausse, Alejandro [CNEA-CONICET and Universidad Nacional del Centro, 7000 Tandil (Argentina); Bruzzone, Horacio [CONICET and Universidad de Mar del Plata, Mar del Plata (Argentina); Castillo, Fermín [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos (Mexico); and others

    2014-12-15

    The characterization of plasma bursts produced after the pinch phase in a plasma focus of hundreds of joules, using pulsed optical refractive techniques, is presented. A pulsed Nd-YAG laser at 532 nm and 8 ns FWHM pulse duration was used to obtain Schlieren images at different times of the plasma dynamics. The energy, interaction time with a target, and power flux of the plasma burst were assessed, providing useful information for the application of plasma focus devices for studying the effects of fusion-relevant pulses on material targets. In particular, it was found that damage factors on targets of the order of 10{sup 4} (W/cm{sup 2})s{sup 1/2} can be obtained with a small plasma focus operating at hundred joules.

  16. Magnetic flux and heat losses by diffusive, advective, and Nernst effects in magnetized liner inertial fusion-like plasma

    Energy Technology Data Exchange (ETDEWEB)

    Velikovich, A. L.; Giuliani, J. L. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Zalesak, S. T. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States)

    2015-04-15

    The magnetized liner inertial fusion (MagLIF) approach to inertial confinement fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010); Cuneo et al., IEEE Trans. Plasma Sci. 40, 3222 (2012)] involves subsonic/isobaric compression and heating of a deuterium-tritium plasma with frozen-in magnetic flux by a heavy cylindrical liner. The losses of heat and magnetic flux from the plasma to the liner are thereby determined by plasma advection and gradient-driven transport processes, such as thermal conductivity, magnetic field diffusion, and thermomagnetic effects. Theoretical analysis based on obtaining exact self-similar solutions of the classical collisional Braginskii's plasma transport equations in one dimension demonstrates that the heat loss from the hot compressed magnetized plasma to the cold liner is dominated by transverse heat conduction and advection, and the corresponding loss of magnetic flux is dominated by advection and the Nernst effect. For a large electron Hall parameter (ω{sub e}τ{sub e}≫1), the effective diffusion coefficients determining the losses of heat and magnetic flux to the liner wall are both shown to decrease with ω{sub e}τ{sub e} as does the Bohm diffusion coefficient cT/(16eB), which is commonly associated with low collisionality and two-dimensional transport. We demonstrate how this family of exact solutions can be used for verification of codes that model the MagLIF plasma dynamics.

  17. Magnetic flux and heat losses by diffusive, advective, and Nernst effects in magnetized liner inertial fusion-like plasma

    Science.gov (United States)

    Velikovich, A. L.; Giuliani, J. L.; Zalesak, S. T.

    2015-04-01

    The magnetized liner inertial fusion (MagLIF) approach to inertial confinement fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010); Cuneo et al., IEEE Trans. Plasma Sci. 40, 3222 (2012)] involves subsonic/isobaric compression and heating of a deuterium-tritium plasma with frozen-in magnetic flux by a heavy cylindrical liner. The losses of heat and magnetic flux from the plasma to the liner are thereby determined by plasma advection and gradient-driven transport processes, such as thermal conductivity, magnetic field diffusion, and thermomagnetic effects. Theoretical analysis based on obtaining exact self-similar solutions of the classical collisional Braginskii's plasma transport equations in one dimension demonstrates that the heat loss from the hot compressed magnetized plasma to the cold liner is dominated by transverse heat conduction and advection, and the corresponding loss of magnetic flux is dominated by advection and the Nernst effect. For a large electron Hall parameter ( ωeτe≫1 ), the effective diffusion coefficients determining the losses of heat and magnetic flux to the liner wall are both shown to decrease with ωeτe as does the Bohm diffusion coefficient c T /(16 e B ) , which is commonly associated with low collisionality and two-dimensional transport. We demonstrate how this family of exact solutions can be used for verification of codes that model the MagLIF plasma dynamics.

  18. Fast ion motion in the plasma part of a stellarator-mirror fission-fusion hybrid

    Science.gov (United States)

    Moiseenko, V. E.; Nemov, V. V.; Ågren, O.; Kasilov, S. V.; Garkusha, I. E.

    2016-06-01

    Recent developments of a stellarator-mirror (SM) fission-fusion hybrid concept are reviewed. The hybrid consists of a fusion neutron source and a powerful sub-critical fast fission reactor core. The aim is transmutation of spent nuclear fuel and safe fission energy production. In its fusion part, a stellarator-type system with an embedded magnetic mirror is used. The stellarator confines deuterium plasma with moderate temperature, 1-2 keV. In the magnetic mirror, a hot component of sloshing tritium ions is trapped. There, the fusion neutrons are generated. A candidate for a combined SM system is a DRACON magnetic trap. A basic idea behind an SM device is to maintain local neutron production in a mirror part, but at the same time eliminate the end losses by using a toroidal device. A possible drawback is that the stellarator part can introduce collision-free radial drift losses, which is the main topic for this study. For high energy ions of tritium with an energy of 70 keV, comparative computations of collisionless losses in the rectilinear part of a specific design of the DRACON type trap are carried out. Two versions of the trap are considered with different lengths of the rectilinear sections. Also the total number of current-carrying rings in the magnetic system is varied. The results predict that high energy ions from neutral beam injection can be satisfactorily confined in the mirror part during 0.1-1 s. The Uragan-2M experimental device is used to check key points of the SM concept. The magnetic configuration of a stellarator with an embedded magnetic mirror is arranged in this device by switching off one toroidal coil. The motion of particles magnetically trapped in the embedded mirror is analyzed numerically with use of motional invariants. It is found that without radial electric field particles quickly drift out of the SM, even if the particles initially are located on a nested magnetic surface. We will show that a weak radial electric field, which

  19. Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy, and Related Fields

    Energy Technology Data Exchange (ETDEWEB)

    L. Grisham and J.W. Kwan

    2008-08-12

    Some years ago it was suggested that halogen negative ions [1] could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons -- can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion-ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.

  20. Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy, and Related Fields

    Energy Technology Data Exchange (ETDEWEB)

    Grisham, L.R.; Kwan, J.W.

    2008-08-01

    Some years ago it was suggested that halogen negative ions [1]could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons -- can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion-ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.

  1. Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy,and Related Fields

    Energy Technology Data Exchange (ETDEWEB)

    Grisham, L. R.; Kwan, J. W.

    2008-08-01

    Some years ago it was suggested that halogen negative ions could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons - can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion - ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.

  2. Z箍缩动态黑腔冲击波辐射图像诊断∗%Sho ck X-ray emission image measurement in Z-pinch dynamic hohlraum

    Institute of Scientific and Technical Information of China (English)

    蒙世坚; 黄展常; 甯家敏; 胡青元; 叶繁; 秦义; 许泽平; 徐荣昆

    2016-01-01

    在“聚龙一号”装置上开展了单层钨丝阵加载重泡沫的动态黑腔实验,初步研究了Z箍缩动态黑腔中冲击波传播和黑腔形成的物理过程.获得了冲击波辐射环的演化图像,分析了丝阵等离子体与泡沫的作用过程及动态黑腔内的辐射特性.测得冲击波的向心传播速度为(14.2±1.7) cm/µs,冲击波平均宽度为0.8—0.9 mm.冲击波辐射环的发光强度沿角向分布的标准偏差约为±10%,中心黑腔区的标准偏差约为±4.2%.%Owing to high efficiency for delivering thermal radiation from Z-pinch plasma to an inertial fusion capsule, Z-pinch dynamic hohlraum (ZPDH) is a promising indirect-drive inertial confinement fusion (ICF) approach. ZPDH is created by accelerating an annular tungsten Z-pinch plasma radially inward to an internal low density convertor. The collision launches a radiating shock traveling inward. Radiations emitted from the shock, after being trapped and thermalized by the optically thick tungsten plasma, drive the internal fusion capsule to implode. In our previous experiments, shock propagating process has never been imaged or even never been formed, due to low drive current (about 1.3 MA). In this paper, the ZPDH has a load of single tungsten wire array embedded in a cylindrical 16 mg/cm3 C15H20O6 foam, and the tungsten wire array is explored using JuLong-1 facility (also named PTS facility) driven by current with a peak value of 7–8 MA and rising time of 60–70 ns (from 10%to 90%). Several results are presented for improving the understanding of the physics of the shock propagating and hohlraum forming. For the high optical depth in tungsten plasmas around the foam, radially directly diagnosing hohlraum radiation distribution along axis is impossible. The most convenient way to diagnose the radiation symmetry and the shock evolution is to take the end-on X-ray images. The time-resolved X-ray images of annular radiating shock evolution, which are performed

  3. The snowflake divertor, physics of a new concept for power exhaust of fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Lunt, Tilmann; Feng, Yuehe [Max-Planck-Institut fuer Plasmaphysik, Garching/Greifswald (Germany); Canal, Gustavo; Reimerdes, Holger [Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland)

    2014-07-01

    Fusion reactors based on the tokamak design will have to deal with very high heat loads on the divertor plates. One of the approaches to solve this heat load problem is the so called 'snowflake divertor', a magnetic configuration with two nearby x-points and two additional divertor legs. In this contribution we report on 'EMC3-Eirene' simulations of the plasma- and neutral particle transport in the scrape-off layer of the swiss tokamak TCV of a series of snowflake equilibria with different values of σ, the distance between the x-points normalized to the minor radius of the plasma. The constant anomalous transport coefficients were chosen such that the power- and particle deposition profiles at the primary inner strike point match the Langmuir probe measurements for the σ=0.1 case. At one of the secondary strike points, however, a significantly larger power flux than that predicted by the simulation was measured by the probes, indicating the presence of an enhanced transport across the primary separatrix. We discuss the possible reason for this enhanced transport as well as its scaling with machine size. Another prediction from the simulation is that the density as well as the radiation maximum are moving from the recycling region in front of the plates upwards to the x-point.

  4. Pulsed, Inductively Generated, Streaming Plasma Ion Source for Heavy Ion Fusion Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Steven C. Glidden; Howard D Sanders; John B. Greenly; Daniel L. Dongwoo

    2006-04-28

    This report describes a compact, high current density, pulsed ion source, based on electrodeless, inductively driven gas breakdown, developed to meet the requirements on normalized emittance, current density, uniformity and pulse duration for an ion injector in a heavy-ion fusion driver. The plasma source produces >10 μs pulse of Argon plasma with ion current densities >100 mA/cm2 at 30 cm from the source and with strongly axially directed ion energy of about 80 eV, and sub-eV transverse temperature. The source has good reproducibility and spatial uniformity. Control of the current density during the pulse has been demonstrated with a novel modulator coil method which allows attenuation of the ion current density without significantly affecting the beam quality. This project was carried out in two phases. Phase 1 used source configurations adapted from light ion sources to demonstrate the feasibility of the concept. In Phase 2 the performance of the source was enhanced and quantified in greater detail, a modulator for controlling the pulse shape was developed, and experiments were conducted with the ions accelerated to >40 kV.

  5. Additive manufacture (3d printing) of plasma diagnostic components and assemblies for fusion experiments

    Science.gov (United States)

    Sieck, Paul; Woodruff, Simon; Stuber, James; Romero-Talamas, Carlos; Rivera, William; You, Setthivoine; Card, Alexander

    2015-11-01

    Additive manufacturing (or 3D printing) is now becoming sufficiently accurate with a large range of materials for use in printing sensors needed universally in fusion energy research. Decreasing production cost and significantly lowering design time of energy subsystems would realize significant cost reduction for standard diagnostics commonly obtained through research grants. There is now a well-established set of plasma diagnostics, but these expensive since they are often highly complex and require customization, sometimes pace the project. Additive manufacturing (3D printing) is developing rapidly, including open source designs. Basic components can be printed for (in some cases) less than 1/100th costs of conventional manufacturing. We have examined the impact that AM can have on plasma diagnostic cost by taking 15 separate diagnostics through an engineering design using Conventional Manufacturing (CM) techniques to determine costs of components and labor costs associated with getting the diagnostic to work as intended. With that information in hand, we set about optimizing the design to exploit the benefits of AM. Work performed under DOE Contract DE-SC0011858.

  6. Development of diffractive XUV-VUV light extractors for fusion plasma diagnostic

    Science.gov (United States)

    Stutman, D.; Caravelli, G.; Delgado-Aparicio, L.; Finkenthal, M.; Tritz, K.; Kaita, R.; Roquemore, L.

    2009-11-01

    The diagnostic and control of next generation MFE and ICF fusion experiments will require optical light extractors capable of withstanding intense plasma and radiation exposure. A solution applicable from the XUV to the infrared is to use free-standing diffractive optics such as transmission gratings or zone plates. Here we present results on XUV-VUV diffractive extractors for the diagnostic of boundary MFE plasmas. For the VUV range we developed Si transmission gratings having 1 μm period, 5 μm thickness, 40% open fraction, 1x2 mm active area, and coated with Ni, while for the XUV range we use SiN gratings having 0.2 μm period, 0.3 μm thickness, 1x1 mm area, and coated with Ta. The grating extractors are spectrally and spatially calibrated in the laboratory using a newly developed extended XUV-VUV source and will be employed for imaging spectrometry on the NSTX experiment. The operational characteristics of the extended source and first space resolved XUV-VUV spectra will be presented. Work supported by DoE Grant DE-FG02-99ER54523 at JHU and Contract DE-AC02-09CH11466 at PU.

  7. Plasma expansion across a transverse magnetic field in a negative hydrogen ion source for fusion

    Science.gov (United States)

    Fantz, U.; Schiesko, L.; Wünderlich, D.

    2014-08-01

    High power negative hydrogen ion sources operating at 0.3 Pa are a key component of the neutral beam injection systems for the international fusion experiment ITER. To achieve the required large ion current at a tolerable number of co-extracted electrons the source is equipped with a magnetic filter field (up to 10 mT). The IPP prototype source (1/8 of the area of the ITER source) has been equipped with a flexible magnetic filter frame to perform filter field studies (position, polarity, strength). Axial profiles of the plasma parameters are measured with two Langmuir probes, positioned in the upper and the lower half of the expansion chamber. In addition to the expected decrease in electron temperature and density a vertical drift develops the direction depending on the polarity of the field. Without field no drift is observed. The drift is less pronounced in caesium seeded discharges and almost vanishes in deuterium, indicating an influence of the ion mass on the drift. A comparison with results from a half-size ITER source reveals that the plasma is much more uniform in the large source.

  8. Synthetic aperture microwave imaging with active probing for fusion plasma diagnostics

    CERN Document Server

    Shevchenko, Vladimir F; Freethy, Simon J; Huang, Billy K

    2012-01-01

    A Synthetic Aperture Microwave Imaging (SAMI) system has been designed and built to obtain 2-D images at several frequencies from fusion plasmas. SAMI uses a phased array of linearly polarised antennas. The array configuration has been optimised to achieve maximum synthetic aperture beam efficiency. The signals received by antennas are down-converted to the intermediate frequency range and then recorded in a full vector form. Full vector signals allow beam focusing and image reconstruction in both real time and a post processing mode. SAMI can scan over 16 preprogrammed frequencies in the range of 10-35GHz with a switching time of 300ns. The system operates in 2 different modes simultaneously: both a passive imaging of plasma emission and also an active imaging of the back-scattered signal of the radiation launched by one of the antennas from the same array. This second mode is similar to so-called Doppler backscattering (DBS) reflectometry with 2-D resolution of the propagation velocity of turbulent structur...

  9. Cryogenic tritium-hydrogen-deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Meezan, N. B., E-mail: meezan1@llnl.gov; Hopkins, L. F. Berzak; Pape, S. Le; Divol, L.; MacKinnon, A. J.; Döppner, T.; Ho, D. D.; Jones, O. S.; Khan, S. F.; Ma, T.; Milovich, J. L.; Pak, A. E.; Ross, J. S.; Thomas, C. A.; Benedetti, L. R.; Bradley, D. K.; Celliers, P. M.; Clark, D. S.; Field, J. E.; Haan, S. W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); and others

    2015-06-15

    High Density Carbon (or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of <10 ns. A series of Inertial Confinement Fusion (ICF) experiments in 2013 on the National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated in a deuterium-tritium (DT) layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a tritium-hydrogen-deuterium (THD) layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightly oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 × 10{sup 15} neutrons, 40% of the 1D simulated yield.

  10. Observation of asymmetric implosions in indirect-drive ICF associated with changes in laser beam-hohlraum coupling and relevance to mix experiments.

    Science.gov (United States)

    Turner, R. E.; Amendt, P. A.; Landen, O. L.; Wallace, R. J.; Thorp, K.; Pien, G.

    2004-11-01

    Indirect drive ICF experiments were performed on the Omega laser at LLE, both with and without distributed polarization rotators (DPR) in the laser beams. The hohlraums were irradiated with a three-cone beam geometry, experimentally adjusted to produce high-yield implosions with no DPRs installed. X-ray images of the cores of these implosions showed a small but tolerable P2 asymmetry. Similar experiments with DPRs installed produced lower yields, and x-ray images of the imploded cores showed substantially increased P2 asymmetries, suggesting that the shallow-angle cone of beams, which transits through the longest length of plasma and along the shallowest density gradients, had substantially increased absorption compared to the no-DPR case. We will show high magnification (nearly 100x) x-ray images of the cores, along with fusion neutron data. For capsules driven with good symmetry, we show the neutron yield results from capsules whose surfaces have been deliberately roughened by a measured amount, in order to compare to mix models in simulations.

  11. 2001 activity report of the development and research line in controlled thermonuclear fusion of the Plasma Associated Laboratory; Relatorio de atividades de 2001 da linha de pesquisa e desenvolvimento em fusao termonuclear controlada (fusao), do Laboratorio Associado de Plasma (LAP)

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Gerson Otto

    2002-07-01

    The year 2001 activities of the controlled thermonuclear fusion research line of the Plasma Associated Laboratory at the National Institute for Space Research - Brazil are reported. The report approaches the staff, participation in congresses, goals for the year 2002 and papers on Tokamak plasmas, plasma diagnostic, bootstraps, plasma equilibrium and diagnostic.

  12. Techniques For Injection Of Pre-Charaterized Dust Into The Scrape Off Layer Of Fusion Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Roquemore, A. L.; John, B.; Friesen, F.; Hartzfeld, K.; Mansfield, D. K.

    2011-07-21

    Introduction of micron-sized dust into the scrape-off layer (SOL) of a plasma has recently found many applications aimed primarily at determining dust behavior in future fusion reactors. The dust particles are typically composed of materials intrinsic to a fusion reactor. On DIII-D and TEXTOR carbon dust has been introduced into the SOL using a probe inserted from below into the divertor region. On NSTX, both Li and tungsten dust have been dropped from the top of the machine into the SOL throughout the duration of a discharge, by utilizing a vibrating piezoelectric based particle dropper. The original particle dropper was developed to inject passivated Li powder {approx} 40 {mu}m in diameter into the SOL to enhance plasma performance. A simplified version of the dropper was developed to introduce trace amounts of tungsten powder for only a few discharges, thus not requiring a large powder reservoir. The particles emit visible light from plasma interactions and can be tracked by either spectroscopic means or by fast frame rate visible cameras. This data can then be compared with dust transport codes such as DUSTT to make predictions of dust behavior in next-step devices such as ITER. For complete modeling results, it is desired to be able to inject pre-characterized dust particles in the SOL at various known poloidal locations, including near the vessel midplane. Purely mechanical methods of injecting particles are presently being studied using a modified piezoelectric-based powder dropper as a particle source and one of several piezo-based transducers to deflect the particles into the SOL. Vibrating piezo fans operating at 60 Hz with a deflection of {+-}2.5 cm can impart a significant horizontal boost in velocity. The highest injection velocities are expected from rotating paddle wheels capable of injecting particles at 10's of meters per second depending primarily on the rotation velocity and diameter of the wheel. Several injection concepts have been tested

  13. Diagnostic systems for the nuclear fusion and plasma research in the PF-24 plasma focus laboratory at the IFJ PAN

    Directory of Open Access Journals (Sweden)

    Marciniak Łukasz

    2016-12-01

    Full Text Available This paper presents a set of diagnostics dedicated to PF-24 - new medium size - plasma focus (PF device built and operated at the Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN. The PF-24 can operate at energy level up to 93 kJ and charging voltage up to 40 kV. Each condenser is connected with a specially designed spark gap with a very small jitter, which ensures a high effi ciency and a low current rise time. The working parameters of PF-24 generator make it a suitable tool for testing new detection systems to be used in fusion research. Four types of such detection systems are presented in this article: three diagnostic systems used to measure electric quantities (Rogowski coil, magnetic probe, capacitance probe, neutron counter based on beryllium activation, fast neutron pinhole camera based on small-area BCF-12 plastic scintillation detectors and high-speed four-frame soft X-ray camera with microchannel plate.

  14. Remote Handling and Plasma Conditions to Enable Fusion Nuclear Science R&D Using a US Component Testing Facility

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Yueng Kay Martin [ORNL; Burgess, Thomas W [ORNL; Carroll, Adam J [ORNL; Neumeyer, C. L. [Princeton Plasma Physics Laboratory (PPPL); Canik, John [ORNL; Cole, Michael J [ORNL; Dorland, W. D. [University of Maryland; Fogarty, P. J. [Oak Ridge National Laboratory (ORNL); Grisham, L. [Princeton Plasma Physics Laboratory (PPPL); Hillis, Donald Lee [ORNL; Katoh, Yutai [ORNL; Korsah, Kofi [ORNL; Kotschenreuther, M. [University of Texas, Austin; LaHaye, R. [General Atomics, San Diego; Mahajan, S. [University of Texas, Austin; Majeski, R. [Princeton Plasma Physics Laboratory (PPPL); Nelson, Brad E [ORNL; Patton, Bradley D [ORNL; Rasmussen, David A [ORNL; Sabbagh, S. A. [Columbia University; Sontag, Aaron C [ORNL; Stoller, Roger E [ORNL; Tsai, C. C. [Oak Ridge National Laboratory (ORNL); Vanlanju, P. [University of Texas, Austin; Wagner, Jill C [ORNL; Yoder, III, Graydon L [ORNL

    2009-08-01

    The use of a fusion component testing facility to study and establish, during the ITER era, the remaining scientific and technical knowledge needed by fusion Demo is considered and described in this paper. This use aims to lest components in an integrated fusion nuclear environment, for the first time, to discover and understand the underpinning physical properties, and to develop improved components for further testing, in a time-efficient manner. It requires a design with extensive modularization and remote handling of activated components, and flexible hot-cell laboratories. It further requires reliable plasma conditions to avoid disruptions and minimize their impact, and designs to reduce the divertor heat flux to the level of ITER design. As the plasma duration is extended through the planned ITER level (similar to 10(3) s) and beyond, physical properties with increasing time constants, progressively for similar to 10(4) s, similar to 10(5) s, and similar to 10(6) s, would become accessible for testing and R&D. The longest time constants of these are likely to be of the order of a week ( 106 S). Progressive stages of research operation are envisioned in deuterium, deuterium-tritium for the ITER duration, and deuterium-tritium with increasingly longer plasma durations. The fusion neutron fluence and operational duty factor anticipated for this "scientific exploration" phase of a component test facility are estimated to be up to 1 MW-yr/m(2) and up to 10%, respectively.

  15. Experimental studies of lithium-based surface chemistry for fusion plasma-facing materials applications

    Energy Technology Data Exchange (ETDEWEB)

    Allain, J.P., E-mail: allain@purdue.ed [Purdue University, West Lafayette, 400 Central Drive, IN 47907 (United States); Rokusek, D.L.; Harilal, S.S. [Purdue University, West Lafayette, 400 Central Drive, IN 47907 (United States); Nieto-Perez, M. [CICATA-IPN, Cerro Blanco 141 Cimatario, Queretaro, QRO 76090 (Mexico); Skinner, C.H.; Kugel, H.W. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Heim, B. [Purdue University, West Lafayette, 400 Central Drive, IN 47907 (United States); Kaita, R.; Majeski, R. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)

    2009-06-15

    Lithium has enhanced the operational performance of fusion devices such as: TFTR, CDX-U, FTU, T-11 M, and NSTX. Lithium in the solid and liquid state has been studied extensively in laboratory experiments including its erosion and hydrogen-retaining properties. Reductions in physical sputtering up to 40-60% have been measured for deuterated solid and liquid lithium surfaces. Computational modeling indicates that up to a 1:1 deuterium volumetric retention in lithium is possible. This paper presents the results of systematic in situ laboratory experimental studies on the surface chemistry evolution of ATJ graphite under lithium deposition. Results are compared to post-mortem analysis of similar lithium surface coatings on graphite exposed to deuterium discharge plasmas in NSTX. Lithium coatings on plasma-facing components in NSTX have shown substantial reduction of hydrogenic recycling. Questions remain on the role lithium surface chemistry on a graphite substrate has on particle sputtering (physical and chemical) as well as hydrogen isotope recycling. This is particularly due to the lack of in situ measurements of plasma-surface interactions in tokamaks such as NSTX. Results suggest that the lithium bonding state on ATJ graphite is lithium peroxide and with sufficient exposure to ambient air conditions, lithium carbonate is generated. Correlation between both results is used to assess the role of lithium chemistry on the state of lithium bonding and implications on hydrogen pumping and lithium sputtering. In addition, reduction of factors between 10 and 30 reduction in physical sputtering from lithiated graphite compared to pure lithium or carbon is also measured.

  16. DIII-D research advancing the scientific basis for burning plasmas and fusion energy

    Science.gov (United States)

    W. M. SolomonThe DIII-D Team

    2017-10-01

    The DIII-D tokamak has addressed key issues to advance the physics basis for ITER and future steady-state fusion devices. In work related to transient control, magnetic probing is used to identify a decrease in ideal stability, providing a basis for active instability sensing. Improved understanding of 3D interactions is emerging, with RMP-ELM suppression correlated with exciting an edge current driven mode. Should rapid plasma termination be necessary, shattered neon pellet injection has been shown to be tunable to adjust radiation and current quench rate. For predictive simulations, reduced transport models such as TGLF have reproduced changes in confinement associated with electron heating. A new wide-pedestal variant of QH-mode has been discovered where increased edge transport is found to allow higher pedestal pressure. New dimensionless scaling experiments suggest an intrinsic torque comparable to the beam-driven torque on ITER. In steady-state-related research, complete ELM suppression has been achieved that is relatively insensitive to q 95, having a weak effect on the pedestal. Both high-q min and hybrid steady-state plasmas have avoided fast ion instabilities and achieved increased performance by control of the fast ion pressure gradient and magnetic shear, and use of external control tools such as ECH. In the boundary, experiments have demonstrated the impact of E× B drifts on divertor detachment and divertor asymmetries. Measurements in helium plasmas have found that the radiation shortfall can be eliminated provided the density near the X-point is used as a constraint in the modeling. Experiments conducted with toroidal rings of tungsten in the divertor have indicated that control of the strike-point flux is important for limiting the core contamination. Future improvements are planned to the facility to advance physics issues related to the boundary, transients and high performance steady-state operation.

  17. The Fifth Workshop on Stochasticity in Fusion Plasmas (Jülich, Germany, 11-14 April 2011) The Fifth Workshop on Stochasticity in Fusion Plasmas (Jülich, Germany, 11-14 April 2011)

    Science.gov (United States)

    Schmitz, Oliver

    2012-05-01

    'Fusion meets chaotic dynamics'—this was the headline for the Fifth International Workshop on Stochasticity in Fusion Plasmas (SFP) held in Jülich, Germany from 11-14 April 2011. This headline reflects a landmark as the generic topic of chaotic dynamical systems has emerged a prominent application by controlling the plasma stability and transport. The workshop facilitated once more gathering of expertise from basic research in the field of non-linear dynamic systems and experts on plasma stability and transport from magnetically confined high temperature plasmas. Resonant magnetic perturbations are used in most large-scale fusion experiments for control of the cyclic high heat flux pulses caused by edge-localized modes in high performance plasmas. This is one of the most prominent applications of non-linear perturbation schemes in modern plasma physics. It was experimentally shown that the edge transport in toroidal magnetic confinement systems as tokamaks and stellarators can be improved towards elimination of transient events, reduction of steady state heat flux densities and reduction of impurity inflow with improvement of the particle confinement. These results sketch the versatile application space of small-scale perturbations for optimization of the rigid magnetic cages used in magnetic confinement of fusion plasmas. At the same time, these experimental observations represent a challenge to theory. The understanding of the experimental observations for extrapolation to future devices is a root requirement in this field of research. Two aspects were dominant in the workshop. First, the question of how the high temperature plasma as highly conductive media with potentially high rotation and plasma drift speeds reacts to a stationary external perturbation was central in all discussions on structural formation, related transport effects and interaction to plasma stability. Second, the topic was highlighted in how far the perturbed system and the final plasma

  18. Advanced tungsten materials for plasma-facing components of DEMO and fusion power plants

    Energy Technology Data Exchange (ETDEWEB)

    Neu, R., E-mail: Rudolf.Neu@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Fakultät für Maschinenbau, Technische Universität München, D-85748 Garching (Germany); Riesch, J. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Coenen, J.W. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, D-52425 Jülich (Germany); Brinkmann, J. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, D-52425 Jülich (Germany); Calvo, A. [CEIT and Tecnun (University of Navarra), E-20018 San Sebastian (Spain); Elgeti, S. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); García-Rosales, C. [CEIT and Tecnun (University of Navarra), E-20018 San Sebastian (Spain); Greuner, H.; Hoeschen, T.; Holzner, G. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Klein, F. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, D-52425 Jülich (Germany); Koch, F. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); and others

    2016-11-01

    Highlights: • Development of W-fibre enhanced W-composites incorporating extrinsic toughening mechanisms. • Production of a large sample (more than 2000 long fibres) for mechanical and thermal testing. • Even in a fully embrittled state, toughening mechanisms are still effective. • Emissions of volatile W-oxides can be suppressed by alloying W with elements forming stable oxides. • WCr10Ti2 has been successfully tested under accidental conditions and high heat fluxes. - Abstract: Tungsten is the major candidate material for the armour of plasma facing components in future fusion devices. To overcome the intrinsic brittleness of tungsten, which strongly limits its operational window, a W-fibre enhanced W-composite material (W{sub f}/W) has been developed incorporating extrinsic toughening mechanisms. Small W{sub f}/W samples show a large increase in toughness. Recently, a large sample (50 mm × 50 mm × 3 mm) with more than 2000 long fibres has been successfully produced allowing further mechanical and thermal testing. It could be shown that even in a fully embrittled state, toughening mechanisms as crack bridging by intact fibres, as well as the energy dissipation by fibre-matrix interface debonding and crack deflection are still effective. A potential problem with the use of pure W in a fusion reactor is the formation of radioactive and highly volatile WO{sub 3} compounds and their potential release under accidental conditions. It has been shown that the oxidation of W can be strongly suppressed by alloying with elements forming stable oxides. WCr10Ti2 alloy has been produced on a technical scale and has been successfully tested in the high heat flux test facility GLADIS. Recently, W-Cr-Y alloys have been produced on a lab-scale. They seem to have even improved properties compared to the previously investigated W alloys.

  19. Evidence of nuclear fusion neutrons in an extremely small plasma focus device operating at 0.1 Joules

    Science.gov (United States)

    Soto, Leopoldo; Pavéz, Cristián; Moreno, José; Altamirano, Luis; Huerta, Luis; Barbaglia, Mario; Clausse, Alejandro; Mayer, Roberto E.

    2017-08-01

    We report on D-D fusion neutron emission in a plasma device with an energy input of only 0.1 J, within a range where fusion events have been considered very improbable. The results presented here are the consequence of scaling rules we have derived, thus being the key point to assure the same energy density plasma in smaller devices than in large machines. The Nanofocus (NF)—our device—was designed and constructed at the P4 Lab of the Chilean Nuclear Energy Commission. Two sets of independent measurements, with different instrumentation, were made at two laboratories, in Chile and Argentina. The neutron events observed are 20σ greater than the background. The NF plasma is produced from a pulsed electrical discharge using a submillimetric anode, in a deuterium atmosphere, showing empirically that it is, in fact, possible to heat and compress the plasma. The strong evidence presented here stretches the limits beyond what was expected. A thorough understanding of this could possibly tell us where the theoretical limits actually lie, beyond conjectures. Notwithstanding, a window is thus open for low cost endeavours for basic fusion research. In addition, the development of small, portable, safe nonradioactive neutron sources becomes a feasible issue.

  20. Low-foot rugby hohlraum experiments on the NIF: Wall-gas mix and a connection with missing x-ray drive energy?

    Science.gov (United States)

    Amendt, Peter; Ross, J. Steven; Schneider, Marilyn; Jones, Oggie; Milovich, Jose; Moody, John

    2014-10-01

    Rugby-shaped hohlraums on the NIF have shown strong symmetry anomalies when simulated with the high-flux model. The wall-gas interface is Rayleigh-Taylor unstable and may lead to the formation of a late-time mix layer that impedes inner- cone propagation, resulting in a drive asymmetry on the capsule. Due to the rugby curvature near the laser entrance hole, the effect of mix may be more pronounced than in cylinders. At the same time a persistent pattern of 15--25% missing energy has been inferred in gas-filled hohlraums (ρ >= 0 . 96 mg/cc). A possible physical connection between formation of a mix layer and the plasma adiabatic lapse rate, where a temperature-gradient reversal is predicted to occur, is explored. Such a profile reversal, in turn, hinders electron conduction to the dense (ρ > 0 . 2 g/cc) Au region responsible for ~900 eV drive x-ray emission, leading to a hotter coronal plasma and reduced hohlraum efficiency. Remedial measures for recovering the loss in hohlraum efficiency through the use of higher-Z gas fills are explored. Prepared by LLNL under Contract DE-AC52-07NA27344.

  1. Ion Acceleration and D-D Nuclear Fusion in Laser-Generated Plasma from Advanced Deuterated Polyethylene

    Directory of Open Access Journals (Sweden)

    Lorenzo Torrisi

    2014-10-01

    Full Text Available Deuterated polyethylene targets have been irradiated by means of a 1016 W/cm2 laser using 600 J pulse energy, 1315 nm wavelength, 300 ps pulse duration and 70 micron spot diameter. The plasma parameters were measured using on-line diagnostics based on ion collectors, SiC detectors and plastic scintillators, all employed in time-of-flight configuration. In addition, a Thomson parabola spectrometer, an X-ray streak camera, and calibrated neutron dosimeter bubble detectors were employed. Characteristic protons and neutrons at maximum energies of 3.0 MeV and 2.45 MeV, respectively, were detected, confirming that energy spectra of reaction products coming from deuterium-deuterium nuclear fusion occur. In thick advanced targets a fusion rate of the order of 2 × 108 fusions per laser shot was calculated.

  2. Research on anisotropy of fusion-produced protons and neutrons emission from high-current plasma-focus discharges

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, K., E-mail: karol.malinowski@ncbj.gov.pl; Sadowski, M. J.; Szydlowski, A. [National Centre for Nuclear Research (NCBJ), 05-400 Otwock (Poland); Institute of Plasma Physics and Laser Microfusion (IFPiLM), 01-497 Warsaw (Poland); Skladnik-Sadowska, E.; Czaus, K.; Kwiatkowski, R.; Zaloga, D. [National Centre for Nuclear Research (NCBJ), 05-400 Otwock (Poland); Paduch, M.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion (IFPiLM), 01-497 Warsaw (Poland)

    2015-01-15

    The paper concerns fast protons and neutrons from D-D fusion reactions in a Plasma-Focus-1000U facility. Measurements were performed with nuclear-track detectors arranged in “sandwiches” of an Al-foil and two PM-355 detectors separated by a polyethylene-plate. The Al-foil eliminated all primary deuterons, but was penetrable for fast fusion protons. The foil and first PM-355 detector were penetrable for fast neutrons, which were converted into recoil-protons in the polyethylene and recorded in the second PM-355 detector. The “sandwiches” were irradiated by discharges of comparable neutron-yields. Analyses of etched tracks and computer simulations of the fusion-products behavior in the detectors were performed.

  3. Ion acceleration and D-D nuclear fusion in laser-generated plasma from advanced deuterated polyethylene.

    Science.gov (United States)

    Torrisi, Lorenzo

    2014-10-23

    Deuterated polyethylene targets have been irradiated by means of a 1016 W/cm2 laser using 600 J pulse energy, 1315 nm wavelength, 300 ps pulse duration and 70 micron spot diameter. The plasma parameters were measured using on-line diagnostics based on ion collectors, SiC detectors and plastic scintillators, all employed in time-of-flight configuration. In addition, a Thomson parabola spectrometer, an X-ray streak camera, and calibrated neutron dosimeter bubble detectors were employed. Characteristic protons and neutrons at maximum energies of 3.0 MeV and 2.45 MeV, respectively, were detected, confirming that energy spectra of reaction products coming from deuterium-deuterium nuclear fusion occur. In thick advanced targets a fusion rate of the order of 2 × 108 fusions per laser shot was calculated.

  4. Characterization of the Plasma Edge for Technique of Atomic Helium Beam in the CIEMAT Fusion Device; Caracterizacion del Borde del Plasma del Dispositivo de Fusion TJ-II del CIEMAT mediante el Diagnostico del Haz Supersonico de Helio

    Energy Technology Data Exchange (ETDEWEB)

    Hidalgo, A.

    2003-07-01

    In this report, the measurement of Electron Temperature and Density in the Boundary Plasma of TJ-II with a Supersonic Helium Beam Diagnostic and work devoted to the upgrading of this technique are described. Also, simulations of Laser Induced Fluorescence (LIF) studies of level populations of electronically excited He atoms are shown. This last technique is now being installed in the CIEMAT fusion device. (Author ) 36 refs.

  5. Laser propagation in simulations of low fill density hohlraums

    Science.gov (United States)

    Meezan, Nathan; Berzak Hopkins, L. F.; Izumi, N.; Divol, L.; Hinkel, D. E.; Ralph, J. E.; Moody, J. D.; Callahan, D. A.

    2016-10-01

    We present analysis of laser propagation in simulations of low fill density hohlraums on the National Ignition Facility (NIF). Simulations using the radiation hydrodynamic code hydra are compared in 2D and 3D. The absorption of laser rays in different materials and spatial locations is extracted from the simulations to identify where and when the inner cone laser beams undergo significant absorption. Inner cone laser beams can be absorbed in the outer cone ``gold bubble'' or in the region where the ablator and hohlraum material interact. The simulations provide guidance on which hohlraum mitigation methods will be most effective at improving inner beam propagation. Prepared by LLNL under Contract DE-AC52-07NA27344.

  6. Damage of actively cooled plasma facing components of magnetic confinement controlled fusion machines

    Energy Technology Data Exchange (ETDEWEB)

    Chevet, G. [Association Euratom-CEA, DSM/DRFC, CEA Cadarache, Saint-Paul-Lez-Durance (France)], E-mail: gaelle.chevet@cea.fr; Schlosser, J. [Association Euratom-CEA, DSM/DRFC, CEA Cadarache, Saint-Paul-Lez-Durance (France); Martin, E.; Herb, V.; Camus, G. [Universite Bordeaux 1, UMR 5801 (CNRS-SAFRAN-CEA-UB1), Laboratoire des Composites Thermostructuraux, F-33600 Pessac (France)

    2009-03-31

    Plasma facing components (PFCs) of magnetic fusion machines have high manufactured residual stresses and have to withstand important stress ranges during operation. These actively cooled PFCs have a carbon fibre composite (CFC) armour and a copper alloy heat sink. Cracks mainly appear in the CFC near the composite/copper interface. In order to analyse damage mechanisms, it is important to well simulate the damage mechanisms both of the CFC and the CFC/Cu interface. This study focuses on the mechanical behaviour of the N11 material for which the scalar ONERA damage model was used. The damage parameters of this model were identified by similarity to a neighbour material, which was extensively analysed, according to the few characterization test results available for the N11. The finite elements calculations predict a high level of damage of the CFC at the interface zone explaining the encountered difficulties in the PFCs fabrication. These results suggest that the damage state of the CFC cells is correlated with a conductivity decrease to explain the temperature increase of the armour surface under fatigue heat load.

  7. Fusion programs in applied plasma physics. Final report, fiscal years 1989--1991

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    The objectives of the theoretical science program are: To support the interpretation of present experiments and predict the outcome of future planned experiments; to improve on existing models and codes and validate against experimental results; and to conduct theoretical physics development of advanced concepts with applications for DIII-D and future devices. Major accomplishments in FY91 include the corroboration between theory and experiment on MHD behavior in the second stable regime of operation on DIII-D, and the frequency and mode structure of toroidal Alfven eigenmodes in high beta, shaped plasmas. We have made significant advances in the development of the gyro-Landau fluid approach to turbulence simulation which more accurately models kinetic drive and damping mechanisms. Several theoretical models to explain the bifurcation phenomenon in L- to H-mode transition were proposed providing the theoretical basis for future experimental verification. The capabilities of new rf codes have been upgraded in response to the expanding needs of the rf experiments. Codes are being employed to plan for a fully non-inductive current drive experiment in a high beta, enhanced confinement regime. GA`s experimental effort in Applied Physics encompasses two advanced diagnostics essential for the operation of future fusion experiments: Alpha particle diagnostic, and current and density profile diagnostics. This paper discusses research in all these topics.

  8. Damage of actively cooled plasma facing components of magnetic confinement controlled fusion machines

    Science.gov (United States)

    Chevet, G.; Schlosser, J.; Martin, E.; Herb, V.; Camus, G.

    2009-03-01

    Plasma facing components (PFCs) of magnetic fusion machines have high manufactured residual stresses and have to withstand important stress ranges during operation. These actively cooled PFCs have a carbon fibre composite (CFC) armour and a copper alloy heat sink. Cracks mainly appear in the CFC near the composite/copper interface. In order to analyse damage mechanisms, it is important to well simulate the damage mechanisms both of the CFC and the CFC/Cu interface. This study focuses on the mechanical behaviour of the N11 material for which the scalar ONERA damage model was used. The damage parameters of this model were identified by similarity to a neighbour material, which was extensively analysed, according to the few characterization test results available for the N11. The finite elements calculations predict a high level of damage of the CFC at the interface zone explaining the encountered difficulties in the PFCs fabrication. These results suggest that the damage state of the CFC cells is correlated with a conductivity decrease to explain the temperature increase of the armour surface under fatigue heat load.

  9. A diamond based neutron spectrometer for diagnostics of deuterium-tritium fusion plasmas

    Science.gov (United States)

    Cazzaniga, C.; Nocente, M.; Rebai, M.; Tardocchi, M.; Calvani, P.; Croci, G.; Giacomelli, L.; Girolami, M.; Griesmayer, E.; Grosso, G.; Pillon, M.; Trucchi, D. M.; Gorini, G.

    2014-11-01

    Single crystal Diamond Detectors (SDD) are being increasingly exploited for neutron diagnostics in high power fusion devices, given their significant radiation hardness and high energy resolution capabilities. The geometrical efficiency of SDDs is limited by the size of commercially available crystals, which is often smaller than the dimension of neutron beams along collimated lines of sight in tokamak devices. In this work, we present the design and fabrication of a 14 MeV neutron spectrometer consisting of 12 diamond pixels arranged in a matrix, so to achieve an improved geometrical efficiency. Each pixel is equipped with an independent high voltage supply and read-out electronics optimized to combine high energy resolution and fast signals (1 MHz) spectroscopy. The response function of a prototype SDD to 14 MeV neutrons has been measured at the Frascati Neutron Generator by observation of the 8.3 MeV peak from the 12C(n, α)9Be reaction occurring between neutrons and 12C nuclei in the detector. The measured energy resolution (2.5% FWHM) meets the requirements for neutron spectroscopy applications in deuterium-tritium plasmas.

  10. A diamond based neutron spectrometer for diagnostics of deuterium-tritium fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Cazzaniga, C., E-mail: carlo.cazzaniga@mib.infn.it; Nocente, M.; Gorini, G. [University of Milano Bicocca, Piazza della Scienza 3, Milano (Italy); Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, via Roberto Cozzi 53, Milano (Italy); Rebai, M.; Giacomelli, L. [University of Milano Bicocca, Piazza della Scienza 3, Milano (Italy); Tardocchi, M.; Croci, G.; Grosso, G. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, via Roberto Cozzi 53, Milano (Italy); Calvani, P.; Girolami, M.; Trucchi, D. M. [CNR-ISM, Research Area Roma 1, Via Salaria km 29.300, 00015-Monterotondo Scalo (Rm) (Italy); Griesmayer, E. [Atominstitut, Vienna University of Technology, Vienna (Austria); Pillon, M. [Associazione EURATOM-ENEA sulla Fusione ENEA C.R. Frascati, Via E. Fermi, 45, 00044 Frascati (Roma) (Italy)

    2014-11-15

    Single crystal Diamond Detectors (SDD) are being increasingly exploited for neutron diagnostics in high power fusion devices, given their significant radiation hardness and high energy resolution capabilities. The geometrical efficiency of SDDs is limited by the size of commercially available crystals, which is often smaller than the dimension of neutron beams along collimated lines of sight in tokamak devices. In this work, we present the design and fabrication of a 14 MeV neutron spectrometer consisting of 12 diamond pixels arranged in a matrix, so to achieve an improved geometrical efficiency. Each pixel is equipped with an independent high voltage supply and read-out electronics optimized to combine high energy resolution and fast signals (<30 ns), which are essential to enable high counting rate (>1 MHz) spectroscopy. The response function of a prototype SDD to 14 MeV neutrons has been measured at the Frascati Neutron Generator by observation of the 8.3 MeV peak from the {sup 12}C(n, α){sup 9}Be reaction occurring between neutrons and {sup 12}C nuclei in the detector. The measured energy resolution (2.5% FWHM) meets the requirements for neutron spectroscopy applications in deuterium-tritium plasmas.

  11. Green and Fast Laser Fusion Technique for Bulk Silicate Rock Analysis by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry.

    Science.gov (United States)

    Zhang, Chenxi; Hu, Zhaochu; Zhang, Wen; Liu, Yongsheng; Zong, Keqing; Li, Ming; Chen, Haihong; Hu, Shenghong

    2016-10-18

    Sample preparation of whole-rock powders is the major limitation for their accurate and precise elemental analysis by laser ablation inductively-coupled plasma mass spectrometry (ICPMS). In this study, a green, efficient, and simplified fusion technique using a high energy infrared laser was developed for major and trace elemental analysis. Fusion takes only tens of milliseconds for each sample. Compared to the pressed pellet sample preparation, the analytical precision of the developed laser fusion technique is higher by an order of magnitude for most elements in granodiorite GSP-2. Analytical results obtained for five USGS reference materials (ranging from mafic to intermediate to felsic) using the laser fusion technique generally agree with recommended values with discrepancies of less than 10% for most elements. However, high losses (20-70%) of highly volatile elements (Zn and Pb) and the transition metal Cu are observed. The achieved precision is within 5% for major elements and within 15% for most trace elements. Direct laser fusion of rock powders is a green and notably simple method to obtain homogeneous samples, which will significantly accelerate the application of laser ablation ICPMS for whole-rock sample analysis.

  12. Contributions to 28th European physical society conference on controlled fusion and plasma physics (Madeira Tecnopolo, Funchal, Portugal, 18-22 June 2001) from LHD experiment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The LHD experimental group has presented nineteen papers at the 28th European Physical Society Conference on Controlled Fusion and Plasma Physics (Madeira Tecnopolo, Funchal, Portugal, 18-22 June 2001). The contributed papers are collected in this report. (author)

  13. Invited and contributed papers presented by the theory group at the joint Varenna-Lausanne international workshop `theory of fusion plasmas`

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    In this report eight invited and contributed papers of the theory group are included which were presented at joint Varenna-Lausanne international workshop on `theory of fusion plasmas`. (author) figs., tabs., refs.

  14. Integrated Prediction and Mitigation Methods of Materials Damage and Lifetime Assessment during Plasma Operation and Various Instabilities in Fusion Devices

    Energy Technology Data Exchange (ETDEWEB)

    Hassanein, Ahmed [Purdue Univ., West Lafayette, IN (United States)

    2015-03-31

    This report describes implementation of comprehensive and integrated models to evaluate plasma material interactions during normal and abnormal plasma operations. The models in full3D simulations represent state-of-the art worldwide development with numerous benchmarking of various tokamak devices and plasma simulators. In addition, significant number of experimental work has been performed in our center for materials under extreme environment (CMUXE) at Purdue to benchmark the effect of intense particle and heat fluxes on plasma-facing components. This represents one-year worth of work and resulted in more than 23 Journal Publications and numerous conferences presentations. The funding has helped several students to obtain their M.Sc. and Ph.D. degrees and many of them are now faculty members in US and around the world teaching and conducting fusion research. Our work has also been recognized through many awards.

  15. Energetic particle-driven compressional Alfvén eigenmodes and prospects for ion cyclotron emission studies in fusion plasmas

    Science.gov (United States)

    Gorelenkov, N. N.

    2016-10-01

    As a fundamental plasma oscillation the compressional Alfvén waves (CAWs) are interesting for plasma scientists both academically and in applications for fusion plasmas. They are believed to be responsible for the ion cyclotron emission (ICE) observed in many tokamaks. The theory of CAW and ICE was significantly advanced at the end of 20th century in particular motivated by first DT experiments on TFTR and subsequent JET DT experimental studies. More recently, ICE theory was advanced by ST (or spherical torus) experiments with the detailed theoretical and experimental studies of the properties of each instability signal. There the instability responsible for ICE signals previously indistinguishable in high aspect ratio tokamaks became the subjects of experimental studies. We discuss further the prospects of ICE theory and its applications for future burning plasma experiments such as the ITER tokamak-reactor prototype being build in France where neutrons and gamma rays escaping the plasma create extremely challenging conditions for fusion alpha particle diagnostics. This manuscript has been authored by Princeton University under Contract Number DE-AC02-09CH11466 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

  16. Final Report: Safety of Plasma Components and Aerosol Transport During Hard Disruptions and Accidental Energy Release in Fusion Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bourham, Mohamed A.; Gilligan, John G.

    1999-08-14

    Safety considerations in large future fusion reactors like ITER are important before licensing the reactor. Several scenarios are considered hazardous, which include safety of plasma-facing components during hard disruptions, high heat fluxes and thermal stresses during normal operation, accidental energy release, and aerosol formation and transport. Disruption events, in large tokamaks like ITER, are expected to produce local heat fluxes on plasma-facing components, which may exceed 100 GW/m{sup 2} over a period of about 0.1 ms. As a result, the surface temperature dramatically increases, which results in surface melting and vaporization, and produces thermal stresses and surface erosion. Plasma-facing components safety issues extends to cover a wide range of possible scenarios, including disruption severity and the impact of plasma-facing components on disruption parameters, accidental energy release and short/long term LOCA's, and formation of airborne particles by convective current transport during a LOVA (water/air ingress disruption) accident scenario. Study, and evaluation of, disruption-induced aerosol generation and mobilization is essential to characterize database on particulate formation and distribution for large future fusion tokamak reactor like ITER. In order to provide database relevant to ITER, the SIRENS electrothermal plasma facility at NCSU has been modified to closely simulate heat fluxes expected in ITER.

  17. Three-dimensional simulations of the angular and polarization dependence of stimulated Brillouin backscattering from NIF hohlraums

    Science.gov (United States)

    Berger, Richard; Langdon, A. B.; Thomas, C. A.; Baker, K. L.; Goyon, C. S.; Turnbull, D. P.

    2016-10-01

    The National Ignition Facility (NIF) groups its 192 beams in 48 quads, 2/3 of which are `outer' beams and 1/3 `inner' beams. Half of the outer quads are focused at the laser entrance hole (LEH) at an mean angle of 44° and the other half at 50° with respect to the hohlraum axis. The majority of the stimulated Brillouin scatter (SBS) is reflected into the 50° quads, and most of that into the 52° beams. That observation we reproduce with our simulations that use the wave propagation code, pF3D. Simulations considered a number of different pulse shapes, wall materials, capsule materials, and initial fill gas density with the plasma properties taken from 2D cylindrically-symmetric, radiation-hydrodynamic simulations of the hohlraum, capsule included. The simulations predict that different hohlraum designs have different fractions, between 20% and 50%, of the total SBS reflected into the backscattered light collection optics (the so-called FABS). The amount of light backscattered outside of FABS is not currently measured but is assumed to be 70% of the light backscattered. That assumption is a reasonable but not accurate estimate. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. Unexpected Up/Down asymmetry measured in axial radiation exiting high-temperature dynamic-hohlraum x-ray source

    Science.gov (United States)

    Sanford, T. W. L.; Lemke, R. W.; Mock, R. C.; Oliver, B. V.; Chandler, G. A.; Leeper, R. J.; Mehlhorn, T. A.; Nash, T. J.; Ruiz, C. L.; Waisman, E. M.; Peterson, D. L.; Chrien, R. E.; Idzorek, G. C.; Watt, R. G.; Roderick, N. F.; Haines, M. G.

    2002-11-01

    A 10 TW radiation source has been developed on the 20-MA Z facility that produces a high-temperature ( 215 eV) x-ray pulse. The pulse is generated in the positive z-direction through a REH (radiation exit hole), primarily from the interior of a collapsing dynamic-hohlraum (DH) centered within a z-pinch [1]. By adding an identical REH at the bottom of the hohlraum, radiation generated in the negative z direction through the bottom offers the possibility of doubling the utility of the hohlraum. Because of the up/down symmetry of the DH about the mid-plane of the z-axis (aside from the power feed), a radiation pulse similar to that exiting the top-REH (anode) is expected leaving the bottom-REH (cathode). Measurements indicate, however, that the peak radiated power exiting the top-REH is 2±0.2 times that exiting the bottom-REH. In contrast, the total energy radiated from either REH is about the same. Detailed measurements of this unexpected asymmetry, apparently dependent on polarity, together with potential origins of the asymmetry are discussed. [1] T. W. L. Sanford, et al, in press, Phys. Plasmas 9, (Aug. 2002). *Sandia is a multi-program laboratory operated by the Sandia Corporation, a Lockheed Martin Company, for the U.S. DOE under Contract No. DE-AC04-94AL85000.

  19. Spectroscopic Investigations of Highly Charged Tungsten Ions - Atomic Spectroscopy and Fusion Plasma Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Clementson, Joel [Lund Univ. (Sweden)

    2010-05-01

    The spectra of highly charged tungsten ions have been investigated using x-ray and extreme ultraviolet spectroscopy. These heavy ions are of interest in relativistic atomic structure theory, where high-precision wavelength measurements benchmark theoretical approaches, and in magnetic fusion research, where the ions may serve to diagnose high-temperature plasmas. The work details spectroscopic investigations of highly charged tungsten ions measured at the Livermore electron beam ion trap (EBIT) facility. Here, the EBIT-I and SuperEBIT electron beam ion traps have been employed to create, trap, and excite tungsten ions of M- and L-shell charge states. The emitted spectra have been studied in high resolution using crystal, grating, and x-ray calorimeter spectrometers. In particular, wavelengths of n = 0 M-shell transitions in K-like W55+ through Ne-like W64+, and intershell transitions in Zn-like W44+ through Co-like W47+ have been measured. Special attention is given to the Ni-like W46+ ion, which has two strong electric-dipole forbidden transitions that are of interest for plasma diagnostics. The EBIT measurements are complemented by spectral modeling using the Flexible Atomic Code (FAC), and predictions for tokamak spectra are presented. The L-shell tungsten ions have been studied at electron-beam energies of up to 122 keV and transition energies measured in Ne-like W64+ through Li-like W71+. These spectra constitute the physics basis in the design of the ion-temperature crystal spectrometer for the ITER tokamak. Tungsten particles have furthermore been introduced into the Sustained Spheromak Physics Experiment (SSPX) spheromak in Livermore in order to investigate diagnostic possibilities of extreme ultraviolet tungsten spectra for the ITER divertor. The spheromak measurement and spectral modeling using FAC suggest that tungsten ions in charge states around Er-like W6+ could be useful for

  20. The role of the boundary plasma in defining the viability of a magnetic fusion reactor: A review

    Science.gov (United States)

    Whyte, Dennis

    2012-10-01

    The boundary of magnetic confinement devices, from the pedestal through to the surrounding surfaces, encompasses an enormous range of plasma and material physics, and their integrated coupling. It is becoming clear that due to fundamental limits of plasma stability and material response the boundary will largely define the viability of an MFE reactor. However we face an enormous knowledge deficit in stepping from present devices and ITER towards a demonstration power plant. We review the boundary and plasma-material interaction (PMI) research required to address this deficit as well as related theoretical/scaling methods for extending present results to future devices. The research activities and gaps are reviewed and organized to three major axes of challenges: power density, plasma duration, and material temperature. The boundary can also be considered a multi-scale system of coupled plasma and material science regulated through the non-linear interface of the sheath. Measurement, theory and modeling across these scales are reviewed. Dimensionless parameters, often used to organized core plasma transport on similarity arguments, can be extended to the boundary plasma, plasma-surface interactions and material response. The scaling methodology suggests intriguing ways forward to prescribe and understand the boundary issues of an eventual reactor in intermediate size devices. Finally, proposed technology and science innovations towards solving the extreme PMI/boundary challenges of magnetic fusion energy will be reviewed.

  1. A new ICRF scenario for bulk ion heating in D-T plasmas: How to utilize intrinsic impurities in fusion devices in our favour

    CERN Document Server

    Kazakov, Y O; Van Eester, D; Bilato, R; Dumont, R; Lerche, E; Mantsinen, M; Messiaen, A

    2015-01-01

    A fusion reactor requires plasma pre-heating before the rate of deuterium-tritium fusion reactions becomes significant. In ITER, radiofrequency (RF) heating of 3He ions, additionally puffed into the plasma, is one of the main options considered for increasing bulk ion temperature during the ramp-up phase of the pulse. In this paper, we propose an alternative scenario for bulk ion heating with RF waves, which requires no extra 3He puff and profits from the presence of intrinsic Beryllium impurities in the plasma. The discussed method to heat Be impurities in D-T plasmas is shown to provide an even larger fraction of fuel ion heating.

  2. 2003 activity report of the development and research line in controlled thermonuclear fusion of the Plasma Associated Laboratory; Relatorio de atividades de 2003 da linha de pesquisa e desenvolvimento em fusao termonuclear controlada - fusao. Laboratorio Associado de Plasma (LAP)

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Gerson Otto

    2004-07-01

    This document represents the 2003 activity report of the development and research line in controlled thermonuclear fusion of the Plasma Associated Laboratory - Brazil, approaching the areas of toroidal systems for magnetic confinement, plasma heating, current generation and high temperature plasma diagnostic.

  3. Laser fusion monthly, February 1981

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstrom, H.G.

    1981-02-01

    This report is divided into the following sections: (1) facility reports (Argus and Shiva); (2) Nova project; and (3) fusion experiments. In the Fusion Experiments section of this report, the author describes the results of a series of experiments on Shiva which further the understanding of the production and transport of suprathermal electrons. He found that of the suprathermal electrons which strike a laser irradiated disk target or which interact with the rear surface of a half Cairn hohlraum target, a significant fraction of these electrons orbit the target and strike the rear of the disk. These results have significant implications in the interpretation and modeling of the laser irradiated target experiments.

  4. Self-organized criticality and the dynamics of near-marginal turbulent transport in magnetically confined fusion plasmas

    Science.gov (United States)

    Sanchez, R.; Newman, D. E.

    2015-12-01

    The high plasma temperatures expected at reactor conditions in magnetic confinement fusion toroidal devices suggest that near-marginal operation could be a reality in future devices and reactors. By near-marginal it is meant that the plasma profiles might wander around the local critical thresholds for the onset of instabilities. Self-organized criticality (SOC) was suggested in the mid 1990s as a more proper paradigm to describe the dynamics of tokamak plasma transport in near-marginal conditions. It advocated that, near marginality, the evolution of mean profiles and fluctuations should be considered simultaneously, in contrast to the more common view of a large separation of scales existing between them. Otherwise, intrinsic features of near-marginal transport would be missed, that are of importance to understand the properties of energy confinement. In the intervening 20 years, the relevance of the idea of SOC for near-marginal transport in fusion plasmas has transitioned from an initial excessive hype to the much more realistic standing of today, which we will attempt to examine critically in this review paper. First, the main theoretical ideas behind SOC will be described. Secondly, how they might relate to the dynamics of near-marginal transport in real magnetically confined plasmas will be discussed. Next, we will review what has been learnt about SOC from various numerical studies and what it has meant for the way in which we do numerical simulation of fusion plasmas today. Then, we will discuss the experimental evidence available from the several experiments that have looked for SOC dynamics in fusion plasmas. Finally, we will conclude by identifying the various problems that still remain open to investigation in this area. Special attention will be given to the discussion of frequent misconceptions and ongoing controversies. The review also contains a description of ongoing efforts that seek effective transport models better suited than traditional

  5. 2012 Joint Varenna-Lausanne International Workshop on the theory of fusion plasmas (Varenna, Italy, 27-31 August 2012)

    Science.gov (United States)

    Gabet, Xavier; Sauter, Olivier

    2013-07-01

    The 2012 Joint Varenna-Lausanne International Workshop on the theory of fusion plasmas was very fruitful. A broad variety of topics was addressed, covering turbulence, magnetohydrodynamics (MHD), edge physics, and radio frequency (RF) wave heating. Moreover, the scope of the meeting was extended this year to include the physics of materials and diagnostics for burning plasmas. This evolution reflects the complexity of problems at hand in fusion, some of them triggered by the construction of ITER and JT-60SA. Long-standing problems without immediate consequences have sometimes become an urgent matter in that context. One may refer to, for instance, the choice of plasma facing components or the design of control systems. Another characteristic of these workshops is the interplay between various domains of plasma physics. For instance, MHD modes are currently investigated with gyrokinetic codes, kinetic effects are included in MHD stability analysis more and more, and turbulence is now accounted for in wave propagation problems. This is proof of cross-fertilization and is certainly a healthy sign for our community. Finally, introducing some novelty in the programme does not prevent from us respecting old traditions. As usual, many presentations were dedicated to numerical simulations. Combining advanced numerical techniques with elaborated analytical theory is certainly a trademark of the Varenna-Lausanne Workshop, which was respected again this year. The quality and size of the scientific output from this workshop is shown in this special issue of Plasma Physics and Controlled Fusion; a further 26 papers have already appeared in Journal of Physics: Conference Series in December 2012. We hope the readers will enjoy this special issue, and find therein knowledge and inspiration.

  6. An experimental investigation of stimulated Brillouin scattering in laser-produced plasmas relevant to inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, K.S. [Univ. of California, Davis, CA (US)

    1993-02-11

    Despite the apparent simplicity of controlled fusion, there are many phenomena which have prevented its achievement. One phenomenon is laser-plasma instabilities. An investigation of one such instability, stimulated Brillouin scattering (SBS), is reported here. SBS is a parametric process whereby an electromagnetic wave (the parent wave) decays into another electromagnetic wave and an ion acoustic wave (the daughter waves). SBS impedes controlled fusion since it can scatter much or all of the incident laser light, resulting in poor drive symmetry and inefficient laser-plasma coupling. It is widely believed that SBS becomes convectively unstable--that is, it grows as it traverses the plasma. Though it has yet to be definitively tested, convective theory is often invoked to explain experimental observations, even when one or more of the theory`s assumptions are violated. In contrast, the experiments reported here not only obeyed the assumptions of the theory, but were also conducted in plasmas with peak densities well below quarter-critical density. This prevented other competing or coexisting phenomena from occurring, thereby providing clearly interpretable results. These are the first SBS experiments that were designed to be both a clear test of linear convective theory and pertinent to controlled fusion research. A crucial part of this series of experiments was the development of a new instrument, the Multiple Angle Time Resolving Spectrometer (MATRS). MATRS has the unique capability of both spectrally and temporally resolving absolute levels of scattered light at many angles simultaneously, and is the first of its kind used in laser-plasma experiments. A detailed comparison of the theoretical predictions and the experimental observations is made.

  7. An in situ accelerator-based diagnostic for plasma-material interactions science on magnetic fusion devices

    Science.gov (United States)

    Hartwig, Zachary S.; Barnard, Harold S.; Lanza, Richard C.; Sorbom, Brandon N.; Stahle, Peter W.; Whyte, Dennis G.

    2013-12-01

    This paper presents a novel particle accelerator-based diagnostic that nondestructively measures the evolution of material surface compositions inside magnetic fusion devices. The diagnostic's purpose is to contribute to an integrated understanding of plasma-material interactions in magnetic fusion, which is severely hindered by a dearth of in situ material surface diagnosis. The diagnostic aims to remotely generate isotopic concentration maps on a plasma shot-to-shot timescale that cover a large fraction of the plasma-facing surface inside of a magnetic fusion device without the need for vacuum breaks or physical access to the material surfaces. Our instrument uses a compact (˜1 m), high-current (˜1 milliamp) radio-frequency quadrupole accelerator to inject 0.9 MeV deuterons into the Alcator C-Mod tokamak at MIT. We control the tokamak magnetic fields - in between plasma shots - to steer the deuterons to material surfaces where the deuterons cause high-Q nuclear reactions with low-Z isotopes ˜5 μm into the material. The induced neutrons and gamma rays are measured with scintillation detectors; energy spectra analysis provides quantitative reconstruction of surface compositions. An overview of the diagnostic technique, known as accelerator-based in situ materials surveillance (AIMS), and the first AIMS diagnostic on the Alcator C-Mod tokamak is given. Experimental validation is shown to demonstrate that an optimized deuteron beam is injected into the tokamak, that low-Z isotopes such as deuterium and boron can be quantified on the material surfaces, and that magnetic steering provides access to different measurement locations. The first AIMS analysis, which measures the relative change in deuterium at a single surface location at the end of the Alcator C-Mod FY2012 plasma campaign, is also presented.

  8. Chloroquine Increases Glucose Uptake via Enhancing GLUT4 Translocation and Fusion with the Plasma Membrane in L6 Cells

    Directory of Open Access Journals (Sweden)

    Qi Zhou

    2016-05-01

    Full Text Available Background/Aims: Chloroquine can induce an increase in the cellular uptake of glucose; however, the underlying mechanism is unclear. Methods: In this study, translocation of GLUT4 and intracellular Ca2+ changes were simultaneously observed by confocal microscope in L6 cells stably over-expressing IRAP-mOrange. The GLUT4 fusion with the plasma membrane (PM was traced using HA-GLUT4-GFP. Glucose uptake was measured using a cell-based glucose uptake assay. GLUT4 protein was detected by Western blotting and mRNA level was detected by RT-PCR. Results: We found that chloroquine induced significant increases in glucose uptake, glucose transporter GLUT4 translocation to the plasma membrane (GTPM, GLUT4 fusion with the PM, and intracellular Ca2+ in L6 muscle cells. Chloroquine-induced increases of GTPM and intracellular Ca2+ were inhibited by Gallein (Gβγ inhibitor and U73122 (PLC inhibitor. However, 2-APB (IP3R blocker only blocked the increase in intracellular Ca2+ but did not inhibit GTPM increase. These results indicate that chloroquine, via the Gβγ-PLC-IP3-IP3R pathway, induces elevation of Ca2+, and this Ca2+ increase does not play a role in chloroqui-ne-evoked GTPM increase. However, GLUT4 fusion with the PM and glucose uptake were significantly inhibited with BAPTA-AM. This suggests that Ca2+ enhances GLUT4 fusion with the PM resulting in glucose uptake increase. Conclusion: Our data indicate that chloroquine via Gβγ-PLC-IP3-IP3R induces Ca2+ elevation, which in turn promotes GLUT4 fusion with the PM. Moreover, chloroquine can enhance GLUT4 trafficking to the PM. These mechanisms eventually result in glucose uptake increase in control and insulin-resistant L6 cells. These findings suggest that chloroquine might be a potential drug for improving insulin tolerance in diabetic patients.

  9. Susceptibility to virus-cell fusion at the plasma membrane is reduced through expression of HIV gp41 cytoplasmic domains.

    Science.gov (United States)

    Malinowsky, Katharina; Luksza, Julia; Dittmar, Matthias T

    2008-06-20

    The cytoplasmic tail of the HIV transmembrane protein plays an important role in viral infection. In this study we analyzed the role of retroviral cytoplasmic tails in modulating the cytoskeleton and interfering with virus-cell fusion. HeLaP4 cells expressing different HIV cytoplasmic tail constructs showed reduced acetylated tubulin levels whereas the cytoplasmic tail of MLV did not alter microtubule stability indicating a unique function for the lentiviral cytoplasmic tail. The effect on tubulin is mediated through the membrane proximal region of the HIV cytoplasmic tail and was independent of membrane localization. Site-directed mutagenesis identified three motifs in the HIV-2 cytoplasmic tail required to effect the reduction in acetylated tubulin. Both the YxxPhi domain and amino acids 21 to 45 of the HIV-2 cytoplasmic tail need to be present to change the level of acetylated tubulin in transfected cells. T-cells stably expressing one HIV-2 cytoplasmic tail derived construct showed also a reduction in acetylated tubulin thus confirming the importance of this effect not only for HeLaP4 and 293T cells. Challenge experiments using transiently transfected HeLaP4 cells and T cells stably expressing an HIV cytoplasmic tail construct revealed both reduced virus-cell fusion and replication of HIV-1(NL4.3) compared to control cells. In the virus-cell fusion assay only virions pseudotyped with either HIV or MLV envelopes showed reduced fusion efficiency, whereas VSV-G pseudotyped virions where not affected by the expression of HIV derived cytoplasmic tail constructs, indicating that fusion at the plasma but not endosomal membrane is affected. Overexpression of human histone-deacetylase 6 (HDAC6) and constitutively active RhoA resulted in a reduction of acetylated tubulin and reduced virus-cell fusion as significant as that observed following expression of HIV cytoplasmic tail constructs. Inhibition of HDAC6 showed a strong increase in acetylated tubulin and increase of

  10. Early Career. Harnessing nanotechnology for fusion plasma-material interface research in an in-situ particle-surface interaction facility

    Energy Technology Data Exchange (ETDEWEB)

    Allain, Jean Paul [Univ. of Illinois, Champaign, IL (United States)

    2014-08-08

    This project consisted of fundamental and applied research of advanced in-situ particle-beam interactions with surfaces/interfaces to discover novel materials able to tolerate intense conditions at the plasma-material interface (PMI) in future fusion burning plasma devices. The project established a novel facility that is capable of not only characterizing new fusion nanomaterials but, more importantly probing and manipulating materials at the nanoscale while performing subsequent single-effect in-situ testing of their performance under simulated environments in fusion PMI.

  11. Spatial and Temporal characterization of plasma properties via emission spectroscopy in fusion materials testing device Proto-MPEX

    Science.gov (United States)

    Morean, Casey; Biewer, Theodore; Shaw, Guinevere; Beers, Josh; Ray, Holly

    2016-10-01

    The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma source, and is intended to study plasma-material interactions (PMI) in conditions similar to those found in future fusion reactors. A high-resolution McPherson Czerny-Turner visible range spectrometer has been utilized to study the behavior of ions in the plasma. Analysis of the spectral lines, D_beta, D_gamma, and D_delta yields valuable information regarding the temperature and density of plasma ions at various locations along Proto-MPEX. Spectroscopic temperature and density measurements are compared to double Langmuir probe measurements to determine plasma behavior as a function of radius. Temporal and spatial measurements along the length of Proto-MPEX are constructed and compared to a photomultiplier tube based diagnostic manufactured at ORNL to determine the plasma's axial behavior along Proto-MPEX. Relative emission of beta, gamma, and delta lines are used to assess recycling effects in the device. This work was supported by the U.S. D.O.E. contract DE-AC05-00OR22725.

  12. Interaction of a self-focused laser beam with a DT fusion target in a plasma-loaded cone-guided ICF scheme

    Science.gov (United States)

    Saedjalil, N.; Mehrangiz, M.; Jafari, S.; Ghasemizad, A.

    2016-06-01

    In this paper, the interaction of a self-focused laser beam with a DT fusion target in a plasma-loaded cone-guided ICF scheme has been presented. We propose here to merge a plasma-loaded cone with the precompressed DT target in order to strongly focus the incident laser beam on the core to improve the fusion gain. The WKB approximation is used to derive a differential equation that governs the evolution of beamwidth of the incident laser beam with the distance of propagation in the plasma medium. The effects of initial plasma and laser parameters, such as initial plasma electron temperature, initial radius of the laser beam, initial laser beam intensity and plasma density, on self-focusing and defocusing of the Gaussian laser beam have been studied. Numerical results indicate that with increasing the plasma frequency (or plasma density) in the cone, the laser beam will be self-focused noticeably, while for a thinner laser beam (with small radius), it will diverge as propagate in the cone. By evaluating the energy deposition of the relativistic electron ignitors in the fuel, the importance of electron transportation in the cone-attached shell was demonstrated. Moreover, by lessening the least energy needed for ignition, the electrons coupling with the pellet enhances. Therefore, it increases the fusion efficiency. In this scheme, with employing a plasma-loaded cone, the fusion process improves without needing an ultrahigh-intensity laser beam in a conventional ICF.

  13. Massachusetts Institute of Technology, Plasma Fusion Center FY97--FY98 work proposal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Alcator C-Mod is the high-field, high-density divertor tokamak in the world fusion program. It is one of five divertor experiments capable of plasma currents exceeding one megamp. Because of its compact dimensions, Alcator C-Mod investigates an essential area in parameter space, which complements the world`s larger experiments, in establishing the tokamak physics database. Three key areas of investigation have been called out in which Alcator C-Mod has a vital role to play: (1) divertor research on C-Mod takes advantage of the advanced divertor shaping, the very high scrap-off-layer power density, unique abilities in impurity diagnosis, and the High-Z metal wall, to advance the physics understanding of this critical topic; (2) in transport studies, C-Mod is making critical tests of both empirical scalings and theoretically based interpretations of tokamak transport, at dimensional parameters that are unique but dimensionless parameters often comparable to those in much larger experiments; (3) in the area of Advanced Tokamak research, so important to concept optimization, the high-field design of the device also provides long pulse length, compared to resistive skin time, which provides an outstanding opportunity to investigate the extent to which enhanced confinement and stability can be sustained in steady-state, using active profile control. In addition to these main programmatic emphasis, important enabling research is being performed in MHD stability and control, which has great significance for the immediate design of ITER, and in the physics and engineering of ICRF, which is the main auxiliary heating method on C-Mod.

  14. LDRD final report on confinement of cluster fusion plasmas with magnetic fields.

    Energy Technology Data Exchange (ETDEWEB)

    Argo, Jeffrey W.; Kellogg, Jeffrey W.; Headley, Daniel Ignacio; Stoltzfus, Brian Scott; Waugh, Caleb J.; Lewis, Sean M.; Porter, John Larry, Jr.; Wisher, Matthew; Struve, Kenneth William; Savage, Mark Edward; Quevedo, Hernan J.; Bengtson, Roger

    2011-11-01

    Two versions of a current driver for single-turn, single-use 1-cm diameter magnetic field coils have been built and tested at the Sandia National Laboratories for use with cluster fusion experiments at the University of Texas in Austin. These coils are used to provide axial magnetic fields to slow radial loss of electrons from laser-produced deuterium plasmas. Typical peak field strength achievable for the two-capacitor system is 50 T, and 200 T for the ten-capacitor system. Current rise time for both systems is about 1.7 {mu}s, with peak current of 500 kA and 2 MA, respectively. Because the coil must be brought to the laser, the driver needs to be portable and drive currents in vacuum. The drivers are complete but laser-plasma experiments are still in progress. Therefore, in this report, we focus on system design, initial tests, and performance characteristics of the two-capacitor and ten-capacitors systems. The questions of whether a 200 T magnetic field can retard the breakup of a cluster-fusion plasma, and whether this field can enhance neutron production have not yet been answered. However, tools have been developed that will enable producing the magnetic fields needed to answer these questions. These are a two-capacitor, 400-kA system that was delivered to the University of Texas in 2010, and a 2-MA ten-capacitor system delivered this year. The first system allowed initial testing, and the second system will be able to produce the 200 T magnetic fields needed for cluster fusion experiments with a petawatt laser. The prototype 400-kA magnetic field driver system was designed and built to test the design concept for the system, and to verify that a portable driver system could be built that delivers current to a magnetic field coil in vacuum. This system was built copying a design from a fixed-facility, high-field machine at LANL, but made to be portable and to use a Z-machine-like vacuum insulator and vacuum transmission line. This system was sent to the

  15. Ablation of a Deuterium Pellet in a Fusion Plasma Viewed as a Stopping Power Problem

    DEFF Research Database (Denmark)

    Chang, C. T.

    1983-01-01

    At present, the most exploited technology to refuel a future fusion reactor is the high speed injection of macroscopic size pellet of solid hydrogen isotopes. The basic idea is that the ablation of a pellet in a fusion reactor is mainly caused by thermal electrons (~ 10 keV) /1/. Due to the low s...

  16. Investigating fusion plasma instabilities in the Mega Amp Spherical Tokamak using mega electron volt proton emissions (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Perez, R. V., E-mail: rvale006@fiu.edu; Boeglin, W. U.; Angulo, A.; Avila, P.; Leon, O.; Lopez, C. [Department of Physics, Florida International University, 11200 SW 8 ST, CP204, Miami, Florida 33199 (United States); Darrow, D. S. [Princeton Plasma Physics Laboratory, James Forrestal Campus, P.O. Box 451, Princeton, New Jersey 08543 (United States); Cecconello, M.; Klimek, I. [Department of Physics and Astronomy, Uppsala University, Uppsala SE-751 20 (Sweden); Allan, S. Y.; Akers, R. J.; Keeling, D. L.; McClements, K. G.; Scannell, R.; Conway, N. J. [CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Turnyanskiy, M. [ITER Physics Department, EFDA CSU Garching, Boltzmannstrasse 2, D-85748, Garching (Germany); Jones, O. M. [CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Michael, C. A. [Australian National University, Canberra ACT 0200 (Australia)

    2014-11-15

    The proton detector (PD) measures 3 MeV proton yield distributions from deuterium-deuterium fusion reactions within the Mega Amp Spherical Tokamak (MAST). The PD’s compact four-channel system of collimated and individually oriented silicon detectors probes different regions of the plasma, detecting protons (with gyro radii large enough to be unconfined) leaving the plasma on curved trajectories during neutral beam injection. From first PD data obtained during plasma operation in 2013, proton production rates (up to several hundred kHz and 1 ms time resolution) during sawtooth events were compared to the corresponding MAST neutron camera data. Fitted proton emission profiles in the poloidal plane demonstrate the capabilities of this new system.

  17. Magnetic Fusion Energy Plasma Interactive and High Heat Flux Components: Volume 5, Technical assessment of critical issues in the steady state operation of fusion confinement devices

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    Critical issues for the steady state operation of plasma confinement devices exist in both the physics and technology fields of fusion research. Due to the wide range and number of these issues, this technical assessment has focused on the crucial issues associated with the plasma physics and the plasma interactive components. The document provides information on the problem areas that affect the design and operation of a steady state ETR or ITER type confinement device. It discusses both tokamaks and alternative concepts, and provides a survey of existing and planned confinement machines and laboratory facilities that can address the identified issues. A universal definition of steady state operation is difficult to obtain. From a physics point of view, steady state is generally achieved when the time derivatives approach zero and the operation time greatly exceeds the characteristic time constants of the device. Steady state operation for materials depends on whether thermal stress, creep, fatigue, radiation damage, or power removal are being discussed. For erosion issues, the fluence and availability of the machine for continuous operation are important, assuming that transient events such as disruptions do not limit the component lifetimes. The panel suggests, in general terms, that steady state requires plasma operation from 100 to 1000 seconds and an availability of more than a few percent, which is similar to the expectations for an ETR type device. The assessment of critical issues for steady state operation is divided into four sections: physics issues; technology issues; issues in alternative concepts; and devices and laboratory facilities that can address these problems.

  18. Proceedings of US/Japan workshop, Q219 on high heat flux components and plasma surface interactions for next fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Ulrickson, M.A.; Stevens, P.L.; Hino, T.; Hirohata, Y. [eds.

    1996-12-01

    This report contains the viewgraphs from the proceedings of US/Japan Workshop on High Heat Flux Components and Plasma Surface Interactions for Next Fusion Devices. Some of the general topics covered by this report are: PFC/PSI in tokamak and helical devices; development of high heat flux components; PSIS and plasma facing materials;tritium; and material damage.

  19. Stabilization effect ofWeibel modes due to inverse bremsstrahlung absorption in laser fusion plasma using Krook collisions model

    Indian Academy of Sciences (India)

    S BELGHIT; A SID

    2016-12-01

    In this work, the Weibel instability due to inverse bremsstrahlung absorption in laser fusion plasma has been investigated. The stabilization effect due to the coupling of the self-generated magnetic field by Weibel instability with the laser wave field is explicitly showed. The main result obtained in this work is that the inclusion of self-generated magnetic field due to Weibel instability to the inverse bremsstrahlung absorption causes a stabilizing effect of excited Weibel modes. We found a decrease in the spectral range of Weibel unstable modes.This decrease is accompanied by a reduction of two orders in the growth rate of instability or even stabilization of these modes. It has been shown that the previous analyses of the Weibel instability due to inverse bremsstrahlunghave overestimated the values of the generated magnetic fields. Therefore, the generation of magnetic fields by the Weibel instability due to inverse bremsstrahlung should not affect the experiences of an inertial confinement fusion.

  20. A new criterion to describe crossed-beam energy transfer in laser-plasma interactions

    Science.gov (United States)

    Trines, R.; Schmitz, H.; Alves, E. P.; Fiuza, F.; Vieira, J.; Silva, L. O.; Bingham, R.

    2016-10-01

    Crossed-beam energy transfer (CBET) between laser beams in underdense plasma is ubiquitous in both direct-drive and indirect-drive inertial confinement fusion. To understand the impact of this process on the final shape of the laser beams involved, as well as their imprint on either hohlraum walls or target surface, a detailed spatial and temporal description of the crossing beams is needed. We have developed an analytical model and derived new criteria describing both the spatial structure and temporal evolution of the beams after crossing. Numerical simulations have been carried out justifying the analytical model and confirming the criteria. The impact of our results on present and future multi-beam experiments in laser fusion and high-energy-density physics, in particular the ``bursty'' nature of beams predicted to occur in NIF experiments, will be discussed.

  1. Optimization of the parameters of plasma liners with zero-dimensional models

    Science.gov (United States)

    Oreshkin, V. I.

    2013-11-01

    The efficiency of conversion of the energy stored in the capacitor bank of a high-current pulse generator into the kinetic energy of an imploding plasma liner is analyzed. The analysis is performed by using a model consisting of LC circuit equations and equations of motion of a cylindrical shell. It is shown that efficient energy conversion can be attained only with a low-inductance generator. The mode of an "ideal" load is considered where the load current at the final stage of implosion is close to zero. The advantages of this mode are, first, high efficiency of energy conversion (80%) and, second, improved stability of the shell implosion. In addition, for inertial confinement fusion realized by the scheme of a Z pinch dynamic hohlraum, not one but several fusion targets can be placed in the cavity on the pinch axis due to the large length of the liner.

  2. X-ray Thomson scattering measurements from hohlraum-driven spheres on the OMEGA laser

    Science.gov (United States)

    Saunders, A. M.; Jenei, A.; Döppner, T.; Falcone, R. W.; Kraus, D.; Kritcher, A.; Landen, O. L.; Nilsen, J.; Swift, D.

    2016-11-01

    X-ray Thomson scattering (XRTS) is a powerful diagnostic for probing warm and hot dense matter. We present the design and results of the first XRTS experiments with hohlraum-driven CH2 targets on the OMEGA laser facility at the Laboratory for Laser Energetics in Rochester, NY. X-rays seen directly from the XRTS x-ray source overshadow the elastic scattering signal from the target capsule but can be controlled in future experiments. From the inelastic scattering signal, an average plasma temperature is inferred that is in reasonable agreement with the temperatures predicted by simulations. Knowledge gained in this experiment shows a promising future for further XRTS measurements on indirectly driven OMEGA targets.

  3. FOREWORD: 12th International Workshop on Plasma-Facing Materials and Components for Fusion Applications 12th International Workshop on Plasma-Facing Materials and Components for Fusion Applications

    Science.gov (United States)

    Kreter, Arkadi; Linke, Jochen; Rubel, Marek

    2009-12-01

    The 12th International Workshop on Plasma-Facing Materials and Components for Fusion Applications (PFMC-12) was held in Forschungszentrum Jülich (FZJ) in Germany in May 2009. This symposium is the successor to the International Workshop on Carbon Materials for Fusion Applications series. Between 1985 and 2003, 10 'Carbon Workshops' were organized in Jülich, Stockholm and Hohenkammer. After this time, the scope of the symposium was redefined to reflect the new requirements of ITER and the ongoing evolution of the field. The workshop was first organized under its new name in 2006 in Greifswald, Germany. The main objective of this conference series is to provide a discussion forum for experts from research institutions and industry dealing with materials for plasma-facing components in present and future controlled fusion devices. The operation of ASDEX-Upgrade with tungsten-coated wall, the fast progress of the ITER-Like Wall Project at JET, the plans for the EAST tokamak to install tungsten, the start of ITER construction and a discussion about the wall material for DEMO all emphasize the importance of plasma-wall interactions and component behaviour, and give much momentum to the field. In this context, the properties and behaviour of beryllium, carbon and tungsten under plasma impact are research topics of foremost relevance and importance. Our community realizes both the enormous advantages and serious drawbacks of all the candidate materials. As a result, discussion is in progress as to whether to use carbon in ITER during the initial phase of operation or to abandon this element and use only metal components from the start. There is broad knowledge about carbon, both in terms of its excellent power-handling capabilities and the drawbacks related to chemical reactivity with fuel species and, as a consequence, about problems arising from fuel inventory and dust formation. We are learning continuously about beryllium and tungsten under fusion conditions, but our

  4. A National Collaboratory to Advance the Science of High Temperature Plasma Physics for Magnetic Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Schissel, David P. [Princeton Plasma Physics Lab., NJ (United States); Abla, G. [Princeton Plasma Physics Lab., NJ (United States); Burruss, J. R. [Princeton Plasma Physics Lab., NJ (United States); Feibush, E. [Princeton Plasma Physics Lab., NJ (United States); Fredian, T. W. [Massachusetts Institute of Technology, Cambridge, MA (United States); Goode, M. M. [Lawrence Berkeley National Lab., CA (United States); Greenwald, M. J. [Massachusetts Institute of Technology, Cambridge, MA (United States); Keahey, K. [Argonne National Lab., IL (United States); Leggett, T. [Argonne National Lab., IL (United States); Li, K. [Princeton Univ., NJ (United States); McCune, D. C. [Princeton Plasma Physics Lab., NJ (United States); Papka, M. E. [Argonne National Lab., IL (United States); Randerson, L. [Princeton Plasma Physics Lab., NJ (United States); Sanderson, A. [Univ. of Utah, Salt Lake City, UT (United States); Stillerman, J. [Massachusetts Institute of Technology, Cambridge, MA (United States); Thompson, M. R. [Lawrence Berkeley National Lab., CA (United States); Uram, T. [Argonne National Lab., IL (United States); Wallace, G. [Princeton Univ., NJ (United States)

    2012-12-20

    This report summarizes the work of the National Fusion Collaboratory (NFC) Project to develop a persistent infrastructure to enable scientific collaboration for magnetic fusion research. The original objective of the NFC project was to develop and deploy a national FES Grid (FusionGrid) that would be a system for secure sharing of computation, visualization, and data resources over the Internet. The goal of FusionGrid was to allow scientists at remote sites to participate as fully in experiments and computational activities as if they were working on site thereby creating a unified virtual organization of the geographically dispersed U.S. fusion community. The vision for FusionGrid was that experimental and simulation data, computer codes, analysis routines, visualization tools, and remote collaboration tools are to be thought of as network services. In this model, an application service provider (ASP provides and maintains software resources as well as the necessary hardware resources. The project would create a robust, user-friendly collaborative software environment and make it available to the US FES community. This Grid's resources would be protected by a shared security infrastructure including strong authentication to identify users and authorization to allow stakeholders to control their own resources. In this environment, access to services is stressed rather than data or software portability.

  5. Verification of gyrokinetic particle simulation of current-driven instability in fusion plasmas. III. Collisionless tearing mode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dongjian [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Southwestern Institution of Physics, Chengdu 610041 (China); Bao, Jian [Fusion Simulation Center, Peking University, Beijing 100871 (China); Han, Tao; Wang, Jiaqi [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Lin, Zhihong, E-mail: zhihongl@uci.edu [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)

    2016-02-15

    A finite-mass electron fluid model for low frequency electromagnetic fluctuations, particularly the collisionless tearing mode, has been implemented in the gyrokinetic toroidal code. Using this fluid model, linear properties of the collisionless tearing mode have been verified. Simulations verify that the linear growth rate of the single collisionless tearing mode is proportional to D{sub e}{sup 2}, where D{sub e} is the electron skin depth. On the other hand, the growth rate of a double tearing mode is proportional to D{sub e} in the parameter regime of fusion plasmas.

  6. Rovibrationally Resolved Time-Dependent Collisional-Radiative Model of Molecular Hydrogen and Its Application to a Fusion Detached Plasma

    Directory of Open Access Journals (Sweden)

    Keiji Sawada

    2016-12-01

    Full Text Available A novel rovibrationally resolved collisional-radiative model of molecular hydrogen that includes 4,133 rovibrational levels for electronic states whose united atom principal quantum number is below six is developed. The rovibrational X 1 Σ g + population distribution in a SlimCS fusion demo detached divertor plasma is investigated by solving the model time dependently with an initial 300 K Boltzmann distribution. The effective reaction rate coefficients of molecular assisted recombination and of other processes in which atomic hydrogen is produced are calculated using the obtained time-dependent population distribution.

  7. High Temperature Dynamic Hohlraums on the Pulsed Power Driver Z.

    Science.gov (United States)

    Nash, Thomas J.

    1998-11-01

    In the concept of the dynamic hohlraum an imploding z-pinch is optically thick to its own radiation. Radiation may be trapped inside the pinch to give a radiation temperature inside the pinch greater than that outside the pinch. The radiation is typically produced by colliding an outer z-pinch liner onto an inner liner. The collision generates a strongly radiating shock, and the radiation is trapped by the outer liner. As the implosion continues after the collision the radiation temperature may continue to increase due to ongoing PdV work done by the implosion. In principal the radiation temperature may increase to the point at which the outer liner burns through, becomes optically thin, and no longer traps the radiation. One application of the dynamic hohlraum is to drive an ICF pellet with the trapped radiation field. Members of the dynamic hohlraum team at Sandia National Labs have used the pulsed power driver Z (20 MA, 100 ns) to create a dynamic hohlraum with temperature linearly ramping from 100 to 180 eV over 5 ns. On this shot zp214 we imploded a nested tungsten wire array of 4 and 2 cm diameters with masses of 2 and 1 mg onto a 2.5 mg plastic annulus at 5 mm diameter. The current return can on this shot was slotted. We anticipate that the radiation temperature may be increased to over 200 eV by stabilizing the pinch with a solid current return can. A current return can with 9 slots imprints 9 filaments onto the imploding pinch. This degrades the optical trapping and the quality of the liner collision. A 1.6 mm diameter capsule situated inside this dynamic hohlraum of zp214 would see 50 kJ of radiation impinging on its surface before the pinch itself collapses to a 1.6 mm diameter. Dynamic hohlraum shots including pellets are scheduled to take place on Z in September of 1998. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the US-DOE under contract DE-AC04-94AL85000.

  8. Simulation of the hohlraum for a laser facility of Megajoule scale

    Energy Technology Data Exchange (ETDEWEB)

    Chizhkov, M N; Kozmanov, M Y U; Lebedev, S N; Lykov, V A; Rykovanova, V V; Seleznev, V N; Selezneva, K I; Stryakhnina, O V; Shestakov, A A; Vronskiy, A V, E-mail: M.N.Chizhkov@VNIITF.r [Russian Federal Nuclear Center - VNIITF Vasilieva str. 13, Snezhinsk, Chelyabinsk reg., 456770 (Russian Federation)

    2010-08-01

    2D calculations of the promising laser hohlraums were performed with using of the Sinara computer code. These hohlraums are intended for achievement of indirectly-driven thermonuclear ignition at laser energy above 1 MJ. Two calculation variants of the laser assembly with the form close to a rugby ball were carried out: with laser entrance hole shields and without shields. Time dependent hohlraum radiation temperature and x-ray flux asymmetry on a target were obtained.

  9. Low-adiabat rugby hohlraum experiments on the National Ignition Facility: Comparison with high-flux modeling and the potential for gas-wall interpenetration

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, Peter, E-mail: amendt1@llnl.gov; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2014-11-15

    hindered inner-beam propagation, due largely to the confluence of rugby shape and low ray angles relative to the hohlraum symmetry axis. A significant inward pointing shift of 500 μm in the outer cones for the third (full energy) shot of the series was used to improve the inner-beam propagation, resulting in a nearly symmetric x-ray self-emission image of the compressed core and reduced sensitivity to mix. Comparatively low time-dependent symmetry swings were also measured, and a significantly lower hot electron fraction was measured for potentially favorable fuel adiabat control. The outer cone stimulated Brillouin scatter levels jumped significantly, but remedial measures such as the use of a boron dopant in the Au wall are planned. A continuing trend of delayed implosion times is found in rugby hohlraums, suggesting levels of unaccounted hohlraum energy (∼150–200 kJ) similar to what is inferred in cylinder hohlraums. A mix-based physical scenario is described, based on suppressed channel heat flux to the dense gold wall from a temperature-gradient reversal induced by a multispecies plasma lapse rate [P. Amendt, C. Bellei, and S. C. Wilks, Phys. Rev. Lett. 109, 075002 (2012)].

  10. Low-adiabat rugby hohlraum experiments on the National Ignition Facility: Comparison with high-flux modeling and the potential for gas-wall interpenetration

    Science.gov (United States)

    Amendt, Peter; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David

    2014-11-01

    inner-beam propagation, due largely to the confluence of rugby shape and low ray angles relative to the hohlraum symmetry axis. A significant inward pointing shift of 500 μm in the outer cones for the third (full energy) shot of the series was used to improve the inner-beam propagation, resulting in a nearly symmetric x-ray self-emission image of the compressed core and reduced sensitivity to mix. Comparatively low time-dependent symmetry swings were also measured, and a significantly lower hot electron fraction was measured for potentially favorable fuel adiabat control. The outer cone stimulated Brillouin scatter levels jumped significantly, but remedial measures such as the use of a boron dopant in the Au wall are planned. A continuing trend of delayed implosion times is found in rugby hohlraums, suggesting levels of unaccounted hohlraum energy (˜150-200 kJ) similar to what is inferred in cylinder hohlraums. A mix-based physical scenario is described, based on suppressed channel heat flux to the dense gold wall from a temperature-gradient reversal induced by a multispecies plasma lapse rate [P. Amendt, C. Bellei, and S. C. Wilks, Phys. Rev. Lett. 109, 075002 (2012)].

  11. Theoretical and experimental study of cyclotronic waves in a fusion plasma; Etude theorique et experimentale des ondes cyclotroniques electroniques dans un plasma de fusion

    Energy Technology Data Exchange (ETDEWEB)

    Vezard, D.

    1994-12-20

    This thesis presents a study concerning cyclotronic waves in a plasma. It starts with an illustration of the elementary interaction between electromagnetic waves and matter.It shows that electrons from tokamak absorbs waves at cyclotronic frequency. Cyclotronic waves are studied by solving the dispersion relation in plasma; it concerns polarisation, absorption, dispersion, extinction. Then, classical theories are reminded in order to speak about decoupled electrons and their interactions. Absorption and emission properties of cyclotronic waves by electrons from a queue are described. After that, cyclotronic waves propagation is studied taking into account resonance. The last part of this thesis is dedicated to the electronic distribution function that is made by a wave spectra at a inferior hybrid frequency. (TEC). 129 refs., 75 figs.

  12. Response to FESAC survey, non-fusion connections to Fusion Energy Sciences. Applications of the FES-supported beam and plasma simulation code, Warp

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Grote, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vay, J. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-05-29

    The Fusion Energy Sciences Advisory Committee’s subcommittee on non-fusion applications (FESAC NFA) is conducting a survey to obtain information from the fusion community about non-fusion work that has resulted from their DOE-funded fusion research. The subcommittee has requested that members of the community describe recent developments connected to the activities of the DOE Office of Fusion Energy Sciences. Two questions in particular were posed by the subcommittee. This document contains the authors’ responses to those questions.

  13. A NATIONAL COLLABORATORY TO ADVANCE THE SCIENCE OF HIGH TEMPERATURE PLASMA PHYSICS FOR MAGNETIC FUSION

    Energy Technology Data Exchange (ETDEWEB)

    Allen R. Sanderson; Christopher R. Johnson

    2006-08-01

    This report summarizes the work of the University of Utah, which was a member of the National Fusion Collaboratory (NFC) Project funded by the United States Department of Energy (DOE) under the Scientific Discovery through Advanced Computing Program (SciDAC) to develop a persistent infrastructure to enable scientific collaboration for magnetic fusion research. A five year project that was initiated in 2001, it the NFC built on the past collaborative work performed within the U.S. fusion community and added the component of computer science research done with the USDOE Office of Science, Office of Advanced Scientific Computer Research. The project was itself a collaboration, itself uniting fusion scientists from General Atomics, MIT, and PPPL and computer scientists from ANL, LBNL, and Princeton University, and the University of Utah to form a coordinated team. The group leveraged existing computer science technology where possible and extended or created new capabilities where required. The complete finial report is attached as an addendum. The In the collaboration, the primary technical responsibility of the University of Utah in the collaboration was to develop and deploy an advanced scientific visualization service. To achieve this goal, the SCIRun Problem Solving Environment (PSE) is used on FusionGrid for an advanced scientific visualization service. SCIRun is open source software that gives the user the ability to create complex 3D visualizations and 2D graphics. This capability allows for the exploration of complex simulation results and the comparison of simulation and experimental data. SCIRun on FusionGrid gives the scientist a no-license-cost visualization capability that rivals present day commercial visualization packages. To accelerate the usage of SCIRun within the fusion community, a stand-alone application built on top of SCIRun was developed and deployed. This application, FusionViewer, allows users who are unfamiliar with SCIRun to quickly create

  14. Radiation Energy Loss from Laser-Heated Shenguang-Ⅱ Hohlraums

    Institute of Scientific and Technical Information of China (English)

    CHANG Tie-Qiang; HUANG Tian-Xuan; SUN Ke-Xu; WANG Guang-Yu; DUAN Qing-Sheng; PEI Wen-Bing; GU Pei-Jun; ZHANG Xing-Hong; DING Yong-Kun; ZHENG Zhi-Jian; YANG Jia-Min

    2004-01-01

    @@ The x ray energy loss out of laser-heated hohlraum through laser entrance holes (LEH) is discussed in detail according to a simple theoretical model and is compared with the hohlraum experimental data measured at Shenguang Ⅱ laser facility. The radiation loss is considered to be composed of two parts, that is, direct contribution from laser spots and re-emitted part from the x ray-heated hohlraum inner wall, and the former accounts for about 20% of the total loss for the Shenguang Ⅱ hohlraums. Owing to the non-equilibrium characteristics of laser target coupling the direct contribution part is non-equilibrium in spectrum.

  15. Self-generated magnetic fields and electron transport in laser driven hohlraums

    Science.gov (United States)

    Edwards, John; Alley, Ed; Hammer, Jim; Town, Richard; Haines, Malcolm

    2002-11-01

    It is well known that magnetic fields can be generated during the interaction of an intense laser beam with solid targets. The principle source of magnetic field from Ohm's law is the familiar grad(T)xgrad(n) term, which results in Megagauss fields for laser intensities typical of inertial fusion and other high energy density experiments. In a hohlraum the main consequence of this is to increase the electron temperature by x2 near the laser entrance holes because of reduced thermal conduction in the cross-field (axial) direction. Despite the "localizing" effect of the magnetic field on the electrons, it appears that the diffusion approximation for electron heat flow breaks down, with the departure becoming progressively worse as the laser power is increased. The results of Lasnex simulations are used to illustrate these effects for laser powers ranging from 10TW to 500TW which cover conditions from Nova to NIF. Potential knock on consequences for inertial fusion are discussed. -This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  16. Accuracy and convergence of coupled finite-volume/Monte Carlo codes for plasma edge simulations of nuclear fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ghoos, K., E-mail: kristel.ghoos@kuleuven.be [KU Leuven, Department of Mechanical Engineering, Celestijnenlaan 300A, 3001 Leuven (Belgium); Dekeyser, W. [KU Leuven, Department of Mechanical Engineering, Celestijnenlaan 300A, 3001 Leuven (Belgium); Samaey, G. [KU Leuven, Department of Computer Science, Celestijnenlaan 200A, 3001 Leuven (Belgium); Börner, P. [Institute of Energy and Climate Research (IEK-4), FZ Jülich GmbH, D-52425 Jülich (Germany); Baelmans, M. [KU Leuven, Department of Mechanical Engineering, Celestijnenlaan 300A, 3001 Leuven (Belgium)

    2016-10-01

    The plasma and neutral transport in the plasma edge of a nuclear fusion reactor is usually simulated using coupled finite volume (FV)/Monte Carlo (MC) codes. However, under conditions of future reactors like ITER and DEMO, convergence issues become apparent. This paper examines the convergence behaviour and the numerical error contributions with a simplified FV/MC model for three coupling techniques: Correlated Sampling, Random Noise and Robbins Monro. Also, practical procedures to estimate the errors in complex codes are proposed. Moreover, first results with more complex models show that an order of magnitude speedup can be achieved without any loss in accuracy by making use of averaging in the Random Noise coupling technique.

  17. Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform

    Science.gov (United States)

    Liu, Yangqing; Tan, Yi; Xie, Huiqiao; Wang, Wenhao; Gao, Zhe

    2014-07-01

    An improved Hilbert-Huang transform method is developed to the time-frequency analysis of non-stationary signals in tokamak plasmas. Maximal overlap discrete wavelet packet transform rather than wavelet packet transform is proposed as a preprocessor to decompose a signal into various narrow-band components. Then, a correlation coefficient based selection method is utilized to eliminate the irrelevant intrinsic mode functions obtained from empirical mode decomposition of those narrow-band components. Subsequently, a time varying vector autoregressive moving average model instead of Hilbert spectral analysis is performed to compute the Hilbert spectrum, i.e., a three-dimensional time-frequency distribution of the signal. The feasibility and effectiveness of the improved Hilbert-Huang transform method is demonstrated by analyzing a non-stationary simulated signal and actual experimental signals in fusion plasmas.

  18. Laser-Plasma Interaction Near the Quarter-Critical Density in Direct-Drive Inertial Confinement Fusion

    Science.gov (United States)

    Maximov, A. V.; Wen, H.; Myatt, J. F.; Short, R. W.; Ren, C.

    2016-10-01

    The laser-plasma interaction (LPI) near the quarter-critical density in direct-drive inertial confinement fusion (ICF) plasmas strongly influences the coupling of laser energy to the target and the generation of fast electrons capable of preheating the target fuel. The full modeling of LPI near the quarter-critical density includes the interplay between two-plasmon decay and stimulated Raman scattering instabilities as well as ion-acoustic perturbations. The results of the kinetic particle-in-cell simulations are in agreement with the simulation results from the fluid-type code. The fast-electron flux and the ω/2 half-omega light spectra are calculated for the parameters relevant to direct-drive ICF experiments on the OMEGA Laser System and at the National Ignition Facility. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  19. Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yangqing, E-mail: liuyq05@gmail.com; Tan, Yi; Xie, Huiqiao; Wang, Wenhao; Gao, Zhe [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

    2014-07-15

    An improved Hilbert-Huang transform method is developed to the time-frequency analysis of non-stationary signals in tokamak plasmas. Maximal overlap discrete wavelet packet transform rather than wavelet packet transform is proposed as a preprocessor to decompose a signal into various narrow-band components. Then, a correlation coefficient based selection method is utilized to eliminate the irrelevant intrinsic mode functions obtained from empirical mode decomposition of those narrow-band components. Subsequently, a time varying vector autoregressive moving average model instead of Hilbert spectral analysis is performed to compute the Hilbert spectrum, i.e., a three-dimensional time-frequency distribution of the signal. The feasibility and effectiveness of the improved Hilbert-Huang transform method is demonstrated by analyzing a non-stationary simulated signal and actual experimental signals in fusion plasmas.

  20. Application and Continued Development of Thin Faraday Collectors as a Lost Ion Diagnostic for Tokamak Fusion Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    F. Ed Cecil

    2011-06-30

    This report summarizes the accomplishment of sixteen years of work toward the development of thin foil Faraday collectors as a lost energetic ion diagnostic for high temperature magnetic confinement fusion plasmas. Following initial, proof of principle accelerator based studies, devices have been tested on TFTR, NSTX, ALCATOR, DIII-D, and JET (KA-1 and KA-2). The reference numbers refer to the attached list of publications. The JET diagnostic KA-2 continues in operation and hopefully will provide valuable diagnostic information during a possible d-t campaign on JET in the coming years. A thin Faraday foil spectrometer, by virtue of its radiation hardness, may likewise provide a solution to the very challenging problem of lost alpha particle measurements on ITER and other future burning plasma machines.

  1. Laser-Plasma Interactions in Drive Campaign targets on the National Ignition Facility

    Science.gov (United States)

    Hinkel, D. E.; Callahan, D. A.; Moody, J. D.; Amendt, P. A.; Lasinski, B. F.; MacGowan, B. J.; Meeker, D.; Michel, P. A.; Ralph, J.; Rosen, M. D.; Ross, J. S.; Schneider, M. B.; Storm, E.; Strozzi, D. J.; Williams, E. A.

    2016-03-01

    The Drive campaign [D A Callahan et al., this conference] on the National Ignition Facility (NIF) laser [E. I. Moses, R. N. Boyd, B. A. Remington, C. J. Keane, R. Al-Ayat, Phys. Plasmas 16, 041006 (2009)] has the focused goal of understanding and optimizing the hohlraum for ignition. Both the temperature and symmetry of the radiation drive depend on laser and hohlraum characteristics. The drive temperature depends on the coupling of laser energy to the hohlraum, and the symmetry of the drive depends on beam-to-beam interactions that result in energy transfer [P. A. Michel, S. H. Glenzer, L. Divol, et al, Phys. Plasmas 17, 056305 (2010).] within the hohlraum. To this end, hohlraums are being fielded where shape (rugby vs. cylindrical hohlraums), gas fill composition (neopentane at room temperature vs. cryogenic helium), and gas fill density (increase of ∼ 150%) are independently changed. Cylindrical hohlraums with higher gas fill density show improved inner beam propagation, as should rugby hohlraums, because of the larger radius over the capsule (7 mm vs. 5.75 mm in a cylindrical hohlraum). Energy coupling improves in room temperature neopentane targets, as well as in hohlraums at higher gas fill density. In addition cross-beam energy transfer is being addressed directly by using targets that mock up one end of a hohlraum, but allow observation of the laser beam uniformity after energy transfer. Ideas such as splitting quads into “doublets” by re-pointing the right and left half of quads are also being pursued. LPI results of the Drive campaign will be summarized, and analyses of future directions presented.

  2. The quest for laboratory inertial fusion burn in the United States

    Science.gov (United States)

    Crandall, D. H.

    2016-05-01

    Ignition and significant fusion yield from inertial confinement fusion (ICF) remains a grand scientific challenge with significant near-term and long-term applications. The ICF community in the U.S. is executing a coordinated effort to explore three viable approaches: laser x-ray drive, laser direct drive, and magnetic direct drive. Cooperative efforts from multiple institutions are directed at the physics basis of each of the three approaches with advancing diagnostics, precision targets, and improved simulations being the basis for the quest. X-ray drive experiments between 2010 and 2012 at the National Ignition Facility (NIF) gave yields much lower than expected because of both challenging hydrodynamics associated with high capsule convergence (∼35×) and laser-plasma instabilities (LPI's) in the hohlraum. Recent experiments employing a variation of the laser pulse and resulting in lower convergence and lower hydrodynamic instability growth gave higher yields approaching 1016 neutrons (for the first time with significant fusion heating of the fuel), roughly in agreement with predictions for that approach. At the Omega Laser Facility the direct laser drive of the capsule is being developed to determine what could be expected if the NIF were reconfigured for spherical direct drive. Recent experiments on OMEGA, hydrodynamically scaled to the NIF, project to yields similar in nature to those of the best x-ray drive cases. Mitigation of cross-beam energy transfer (CBET) is required for improvement in direct-drive implosions. At the Z pulsed-power facility, a new approach of magnetically pinching a cylinder containing magnetized and laser- heated plasma shows promise for attaining significant fusion yield. Improvements in this technique are being addressed at a number of facilities. In addition to the fusion-yield experiments, a number of basic science studies use the advanced facilities to study plasma physics, materials science, and astrophysical phenomena at

  3. Local transport barrier formation and relaxation in reverse-shear plasmas on the Tokamak Fusion Test Reactor

    Science.gov (United States)

    Synakowski, E. J.; Batha, S. H.; Beer, M. A.; Bell, M. G.; Bell, R. E.; Budny, R. V.; Bush, C. E.; Efthimion, P. C.; Hahm, T. S.; Hammett, G. W.; LeBlanc, B.; Levinton, F.; Mazzucato, E.; Park, H.; Ramsey, A. T.; Schmidt, G.; Rewoldt, G.; Scott, S. D.; Taylor, G.; Zarnstorff, M. C.

    1997-05-01

    The roles of turbulence stabilization by sheared E×B flow and Shafranov shift gradients are examined for Tokamak Fusion Test Reactor [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)] enhanced reverse-shear (ERS) plasmas. Both effects in combination provide the basis of a positive-feedback model that predicts reinforced turbulence suppression with increasing pressure gradient. Local fluctuation behavior at the onset of ERS confinement is consistent with this framework. The power required for transitions into the ERS regime are lower when high power neutral beams are applied earlier in the current profile evolution, consistent with the suggestion that both effects play a role. Separation of the roles of E×B and Shafranov shift effects was performed by varying the E×B shear through changes in the toroidal velocity with nearly steady-state pressure profiles. Transport and fluctuation levels increase only when E×B shearing rates are driven below a critical value that is comparable to the fastest linear growth rates of the dominant instabilities. While a turbulence suppression criterion that involves the ratio of shearing to linear growth rates is in accord with many of these results, the existence of hidden dependencies of the criterion is suggested in experiments where the toroidal field was varied. The forward transition into the ERS regime has also been examined in strongly rotating plasmas. The power threshold is higher with unidirectional injection than with balance injection.

  4. Temperature measurements of fusion plasmas produced by petawatt laser-irradiated D2-3He or CD4-3He clustering gases

    CERN Document Server

    Bang, W; Bonasera, A; Dyer, G; Quevedo, H J; Hagel, K; Schmidt, K; Consoli, F; De Angelis, R; Andreoli, P; Gaul, E; Bernstein, A C; Donovan, M; Barbarino, M; Kimura, S; Mazzocco, M; Sura, J; Natowitz, J B; Ditmire, T

    2013-01-01

    Two different methods have been employed to determine the plasma temperature in a laser-cluster fusion experiment on the Texas Petawatt laser. In the first, the temperature was derived from time-of-flight data of deuterium ions ejected from exploding D2 or CD4 clusters. In the second, the temperature was measured from the ratio of the rates of two different nuclear fusion reactions occurring in the plasma at the same time: D(d, 3He)n and 3He(d, p)4He. The temperatures determined by these two methods agree well, which indicates that: i) The ion energy distribution is not significantly distorted when ions travel in the disassembling plasma; ii) The kinetic energy of deuterium ions, especially the hottest part responsible for nuclear fusion, is well described by a near-Maxwellian distribution.

  5. Characterization of the pH-induced fusion of liposomes with the plasma membrane of rye protoplasts

    Energy Technology Data Exchange (ETDEWEB)

    Arvinte , T.; Steponkus, P.L.

    1988-07-26

    The authors present evidence that at acidic pH, liposomes composed of soybean lipids fuse with the plasma membrane of protoplasts isolated from rye leaves. Using the resonance energy transfer assay (RET), they determined the rate and extent of liposome and protoplast plasma membrane lipid mixing. The fluorescent donor-acceptor pair was N-(7-nitro-2,1,3-benzoxadiazol-4-yl)phosphatidyl-ethanolamine (N-NBD-PE) and N-(lissamine rhodamine B sulfonyl)phosphatidylethanolamine (N-Rh-PE). Fusion was substantial below pH 5, and the half-time of lipid mixing was fast (t/sub 1/2/ on the order of minutes) and pH, concentration, and temperature dependent. The extent of liposome and protoplast fusion from the total amount of liposomes associated with the protoplasts was also determined by the RET assay. Protoplasts were incubated with fluorescent-labeled liposomes (5 min at 30/sup 0/C) at different pH values and then washed twice by centrifugation. The fluorescence spectra of the protoplast suspension permitted determination of the ratio of N-NBD-PE emission at 530 nm to the N-Rh-PE emission at 590 nm, which is a measure of the degree of lipid mixing. The amount of liposomes associated (fused and unfused) with protoplasts at pH 3.9 was approximately 9 times greater than that at pH 5.6. The transfer of liposome contents to the protoplast interior was studied with a method based on the fluorescence enhancement of a solution of calcein, initially confined in the liposomes at self-quenching concentrations. The kinetics of calcein release were very similar to those of lipid mixing. Fluorescence microscopy showed that after fusion with liposomes containing calcein, the protoplasts exhibited a strong diffuse fluorescence in the interior.

  6. Enthalpy generation from mixing in hohlraum-driven targets

    Science.gov (United States)

    Amendt, Peter; Milovich, Jose

    2016-10-01

    The increase in enthalpy from the physical mixing of two initially separated materials is analytically estimated and applied to ICF implosions and gas-filled hohlraums. Pressure and temperature gradients across a classical interface are shown to be the origin of enthalpy generation from mixing. The amount of enthalpy generation is estimated to be on the order of 100 Joules for a 10 micron-scale annular mixing layer between the solid deuterium-tritium fuel and the undoped high-density carbon ablator of a NIF-scale implosion. A potential resonance is found between the mixing layer thickness and gravitational (Cs2/ g) and temperature-gradient scale lengths, leading to elevated enthalpy generation. These results suggest that if mixing occurs in current capsule designs for the National Ignition Facility, the ignition margin may be appreciably eroded by the associated enthalpy of mixing. The degree of enthalpy generation from mixing of high- Z hohlraum wall material and low- Z gas fills is estimated to be on the order of 100 kJ or more for recent NIF-scale hohlraum experiments, which is consistent with the inferred missing energy based on observed delays in capsule implosion times. Work performed under the auspices of Lawrence Livermore National Security, LLC (LLNS) under Contract No. DE-AC52-07NA27344.

  7. EURATOM-CEA association contributions to the 26. EPS conference on controlled fusion and plasma physics, Maastricht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-10-15

    This report references the EURATOM-CEA association contributions presented at the 26. EPS conference on controlled fusion and plasma physics, in Maastricht (Netherlands) the 14-18 June 1999. Two invited papers and 24 contributed papers are proposed. They deal with: tokamak devices; particle recirculation in ergodic divertor; current profile control and MHD stability in Tore Supra discharges; edge-plasma control by the ergodic divertor; electron heat transport in stochastic magnetic layer; bolometry and radiated power; particle collection by ergodic divertor; study and simulation of pa impurities; line shape modelling for plasma edge conditions; dynamical study of the radial structure of the fluctuations measured by reciprocating Langmuir probe in Tore Supra; up-down asymmetry of density fluctuations; Halo currents in a circular tokamak; real time measurement of the position, density, profile and current profile at Tore Supra; poloidal rotation measurement by reflectometry; interpretation of q-profile dependence of the LH power deposition profile during LHCD experiments; ICFR plasma production and optimization; improved core electron confinement; measurement of hard X-ray emission profile; modelling of shear effects on thermal and particles transport; ion turbulence; current drive generation based on autoresonance and intermittent trapping mechanisms. (A.L.B.)

  8. Two decades of progress in understanding and control of laser plasma instabilities in indirect drive inertial fusion

    Science.gov (United States)

    Montgomery, David S.

    2016-05-01

    Our understanding of laser-plasma instability (LPI) physics has improved dramatically over the past two decades through advancements in experimental techniques, diagnostics, and theoretical and modeling approaches. We have progressed from single-beam experiments—ns pulses with ˜kJ energy incident on hundred-micron-scale target plasmas with ˜keV electron temperatures—to ones involving nearly 2 MJ energy in 192 beams onto multi-mm-scale plasmas with temperatures ˜4 keV. At the same time, we have also been able to use smaller-scale laser facilities to substantially improve our understanding of LPI physics and evaluate novel approaches to their control. These efforts have led to a change in paradigm for LPI research, ushering in an era of engineering LPI to accomplish specific objectives, from tuning capsule implosion symmetry to fixing nonlinear saturation of LPI processes at acceptable levels to enable the exploration of high energy density physics in novel plasma regimes. A tutorial is provided that reviews the progress in the field from the vantage of the foundational LPI experimental results. The pedagogical framework of the simplest models of LPI will be employed, but attention will also be paid to settings where more sophisticated models are needed to understand the observations. Prospects for the application of our improved understanding for inertial fusion (both indirect- and direct-drive) and other applications will also be discussed.

  9. Models and Simulations of C60-Fullerene Plasma Jets for Disruption Mitigation and Magneto-Inertial Fusion

    Science.gov (United States)

    Bogatu, Ioan-Niculae; Galkin, Sergei A.; Kim, Jin-Soo

    2009-11-01

    We present the models and simulation results of C60-fullerene plasma jets proposed to be used for the disruption mitigation on ITER and for magneto-inertial fusion (MIF). The model describing the fast production of a large mass of C60 molecular gas in the pulsed power source by explosive sublimation of C60 micro-grains is detailed. Several aspects of the magnetic ``piston'' model and the 2D interchange (magnetic Rayleigh-Taylor) instability in the rail gun arc dynamics are described. A plasma jet adiabatic expansion model is used to investigate the in-flight three-body recombination during jet transport to the plasma boundary. Our LSP PIC code 3D simulations show that heavy C60 plasmoid penetrates deeply through a transverse magnetic barrier demonstrating self-polarization and magnetic field expulsion effects. The LSP code 3D simulation of two plasma jets head-on injection along a magnetic field lines for MIF are also discussed.

  10. New linear plasma devices in the trilateral euregio cluster for an integrated approach to plasma surface interactions in fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Unterberg, B., E-mail: b.unterberg@fz-juelich.de [Institut fuer Energieforschung - Plasmaphysik, Forschungszentrum Juelich GmbH, Association EURATOM- Forschungszentrum Juelich, D-52425 Juelich (Germany); Jaspers, R. [Science and Technology of Nuclear Fusion, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Koch, R. [Laboratoire de Physique des Plasmas/Laboratorium voor Plasmafysica, ERM/KMS, EURATOM-Association, B-1000 Brussels (Belgium); Massaut, V. [SCK-CEN, Belgian Nuclear Research Centre, EURATOM-Association, Boeretang 200, 2400 Mol (Belgium); Rapp, J. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Reiter, D.; Kraus, S.; Kreter, A.; Philipps, V.; Reimer, H.; Samm, U.; Scheibl, L.; Schweer, B. [Institut fuer Energieforschung - Plasmaphysik, Forschungszentrum Juelich GmbH, Association EURATOM- Forschungszentrum Juelich, D-52425 Juelich (Germany); Schuurmans, J.; Uytdenhouwen, I. [SCK-CEN, Belgian Nuclear Research Centre, EURATOM-Association, Boeretang 200, 2400 Mol (Belgium); Al, R.; Berg, M.A. van den; Brons, S.; Eck, H.J.N. van; Goedheer, W.J. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, PO Box 1207, 3430 BE Nieuwegein (Netherlands)

    2011-10-15

    New linear plasma devices are currently being constructed or planned in the Trilateral Euregio Cluster (TEC) to meet the challenges with respect to plasma surface interactions in DEMO and ITER: i) MAGNUM-PSI (FOM), a high particle and power flux device with super-conducting magnetic field coils which will reach ITER-like divertor conditions at high magnetic field, ii) the newly proposed linear plasma device JULE-PSI (FZJ), which will allow to expose toxic and neutron activated target samples to ITER-like fluences and ion energies including in vacuo analysis of neutron activated samples, and iii) the plasmatron VISION I, a compact plasma device which will be operated inside the tritium lab at SCK-CEN Mol, capable to investigate tritium plasmas and moderately activated wall materials. This contribution shows the capabilities of the new devices and their forerunner experiments (Pilot-PSI at FOM and PSI-2 Juelich at FZJ) in view of the main objectives of the new TEC program on plasma surface interactions.

  11. Collisional current drive in two interpenetrating plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D. D.; Kugland, N. L.; Park, H.-S.; Pollaine, S. M.; Remington, B. A.; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2011-10-15

    The magnetic field generation in two interpenetrating, weakly collisional plasma streams produced by intense lasers is considered. The generation mechanism is very similar to the neutral beam injection current drive in toroidal fusion devices, with the differences related to the absence of the initial magnetic field, short interaction time, and different geometry. Spatial and temporal characteristics of the magnetic field produced in two counterstreaming jets are evaluated; it is shown that the magnetic field of order of 1 T can be generated for modest jet parameters. Conditions under which this mechanism dominates that of the ''Biermann battery'' are discussed. Other settings where the mechanism of the collisional current drive can be important for the generation of seed magnetic fields include astrophysics and interiors of hohlraums.

  12. Degenerate Bogdanov-Takens bifurcations in a one-dimensional transport model of a fusion plasma

    NARCIS (Netherlands)

    de Blank, H. J.; Kuznetsov, Y. A.; Pekker, M. J.; Veldman, D. W. M.

    2016-01-01

    Experiments in tokamaks (nuclear fusion reactors) have shown two modes of operation: L-mode and H-mode. Transitions between these two modes have been observed in three types: sharp, smooth and oscillatory. The same modes of operation and transitions between them have been observed in simplified

  13. Numerical simulation by a random particle method of Deuterium-Tritium fusion reactions in a plasma*

    Directory of Open Access Journals (Sweden)

    Charles Fréderique

    2013-01-01

    Full Text Available We propose and we justify a Monte-Carlo algorithm which solves a spatially homogeneous kinetic equation of Boltzmann type that models the fusion reaction between a deuterium ion and a tritium ion, and giving an α particle and a neutron. The proposed algorithm is validated with the use of explicit solutions of the kinetic model obtained by replacing the fusion cross-section by a Maxwellian cross section. On propose et on justifie un algorithme de type Monte-Carlo permettant de résoudre un modèle cinétique homogène en espace de type Boltzmann modélisant la réaction de fusion entre un ion deutérium et un ion tritium, et donnant une particule α et un neutron. L’algorithme proposé est par ailleurs validé via des solutions explicites du modèle cinétique obtenues en remplaçant la section efficace de fusion par une section efficace maxwellienne.

  14. Controlled Nuclear Fusion.

    Science.gov (United States)

    Glasstone, Samuel

    This publication is one of a series of information booklets for the general public published by The United States Atomic Energy Commission. Among the topics discussed are: Importance of Fusion Energy; Conditions for Nuclear Fusion; Thermonuclear Reactions in Plasmas; Plasma Confinement by Magnetic Fields; Experiments With Plasmas; High-Temperature…

  15. Performance Test of Korea Heat Load Test Facility (KoHLT-EB) for the Plasma Facing Components of Fusion Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Suk-Kwon; Jin, Hyung Gon; Lee, Eo Hwak; Yoon, Jae-Sung; Lee, Dong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The main components of the plasma facing components (PFCs) in the tokamak are the blanket first wall and divertor, which include the armour materials, the heat sink with the cooling mechanism, and the diagnostics devices for the temperature measurement. The Korea Heat Load Test facility by using electron beam (KoHLT-EB) has been operating for the plasma facing components to develop fusion engineering. This electron beam facility was constructed using a 300 kW electron gun and a cylindrical vacuum chamber. Performance tests were carried out for the calorimetric calibrations with Cu dummy mockup and for the heat load test of large Cu module. For the simulation of the heat load test of each mockup, the preliminary thermal-hydraulic analyses with ANSYS-CFX were performed. For the development of the plasma facing components in the fusion reactors, test mockups were fabricated and tested in the high heat flux test facility. To perform a beam profile test, an assessment of the possibility of electron beam Gaussian power density profile and the results of the absorbed power for that profile before the test starts are needed. To assess the possibility of a Gaussian profile, for the qualification test of the Gaussian heat load profile, a calorimeter mockup and large Cu module were manufactured to simulate real heat. For this high-heat flux test, the Korean high-heat flux test facility using an electron beam system was constructed. In this facility, a cyclic heat flux test will be performed to measure the surface heat flux, surface temperature profile, and cooling capacity.

  16. Resonance between heat-carrying electrons and Langmuir waves in inertial confinement fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rozmus, W. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada); Chapman, T.; Berger, R. L. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Brantov, A.; Bychenkov, V. Yu. [P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow 119991 Russia and Center for Fundamental and Applied Research, VNIIA, ROSATOM, 127055 Moscow (Russian Federation); Winjum, B. J. [Department of Electrical Engineering, UCLA, Los Angeles, California 90095 (United States); Brunner, S. [Association EURATOM-Confederation Suisse, EPFL, 1015 Lausanne (Switzerland); Tableman, A.; Tzoufras, M. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States); Glenzer, S. [LCLS, Stanford, California 94025 (United States)

    2016-01-15

    In ignition scale hot plasmas, temperature gradients and thermal transport modify electron distributions in a velocity range resonant with Langmuir waves typical of those produced by stimulated Raman scattering. We examine the resultant changes to the Landau damping experienced by these Langmuir waves and the levels of thermal plasma fluctuations. The form factor and Thomson scattering cross-section in such plasmas display unique characteristics of the background conditions. A theoretical model and high-order Vlasov-Fokker-Planck simulations are used in our analysis. An experiment to measure changes in thermal plasma fluctuation levels due to a thermal gradient is proposed.

  17. Ablation of high-Z material dust grains in edge plasmas of magnetic fusion devices

    Science.gov (United States)

    Marenkov, E. D.; Krasheninnikov, S. I.

    2014-12-01

    The model, including shielding effects of high-Z dust grain ablation in tokamak edge plasma, is presented. In a contrast to shielding models developed for pellets ablation in a hot plasma core, this model deals with the dust grain ablation in relatively cold edge plasma. Using some simplifications, a closed set of equations determining the grain ablation rate Γ is derived and analyzed both analytically and numerically. The scaling law for Γ versus grain radius and ambient plasma parameters is obtained and confirmed by the results of numerical solutions. The results obtained are compared with both dust grain models containing no shielding effects and the pellet ablation models.

  18. EDITORIAL: Theory of fusion plasmas: selected papers from the Joint Varenna-Lausanne International Workshop Theory of fusion plasmas: selected papers from the Joint Varenna-Lausanne International Workshop

    Science.gov (United States)

    Garbet, X.; Sauter, O.

    2011-05-01

    The 2010 edition of the joint Varenna-Lausanne workshop on the theory of fusion plasmas was undoubtedly a great success. The programme encompasses a wide variety of topics, namely turbulence, MHD, edge physics and RF wave heating. The present PPCF issue is a collection of 19 outstanding papers, which cover these topics. It follows the publication of 22 refereed contributed papers in Journal of Physics: Conference Series 2010 260. There is no doubt that the production of articles was both abundant and of high scientific quality. This is why the Varenna-Lausanne meeting takes an important place in the landscape of conferences on fusion. Indeed this is the ideal forum for exchanging ideas on theory and modelling, and for substantiating the best results obtained in our field. The tradition of the meeting is to provide a forum for numerical modelling activities. This custom was clearly respected given the large fraction of papers in this special issue which address this subject. This feature reflects the revolution we have been living through for some years with the fast growth of high-performance computers. It also appears that analytical theory is flourishing. This is important for bringing new ideas and guidance to numerical simulations. Finally, code validation and comparison to experiments are well represented. We believe that this is good news given the complexity of the non-linear physics that is at stake in fusion devices. Another subject of satisfaction was the presence of many young scientists at the meeting. The encounter between young researchers and senior scientists is certainly a strong point of the Varenna-Lausanne conference. In conclusion, we anticipate a great success for this special issue of PPCF and we hope that the readers will find therein ideas and inspiration.

  19. Fusion research principles

    CERN Document Server

    Dolan, Thomas James

    2013-01-01

    Fusion Research, Volume I: Principles provides a general description of the methods and problems of fusion research. The book contains three main parts: Principles, Experiments, and Technology. The Principles part describes the conditions necessary for a fusion reaction, as well as the fundamentals of plasma confinement, heating, and diagnostics. The Experiments part details about forty plasma confinement schemes and experiments. The last part explores various engineering problems associated with reactor design, vacuum and magnet systems, materials, plasma purity, fueling, blankets, neutronics

  20. Core Plasma Characteristics of a Spherical Tokamak D-3He Fusion Reactor

    Institute of Scientific and Technical Information of China (English)

    Shi Bingren

    2005-01-01

    The magnetic fusion reactor using the advanced D-3He fuels has the advantage of much less-neutron productions so that the consequent damages to the first wall are less serious. If the establishment of this kind of reactor becomes realistic, the exploration of 3He on the moon will be largely motivated. Based on recent progresses in the spherical torus (ST) research, we have physically designed a D-3He fusion reactor using the extrapolated results from the ST experiments and also the present-day tokamak scaling. It is found that the reactor size significantly depends on the wall reflection coefficient of the synchrotron radiation and of the impurity contaminations.The secondary reaction between D-D that promptly leads to the D-T reaction producing 14 MeV neutrons is also estimated. Comparison of this D-3He ST reactor with the D-T reactor is made.

  1. In depth fusion flame spreading with a deuterium-tritium plane fuel density profile for plasma block ignition

    Institute of Scientific and Technical Information of China (English)

    B.Malekynia; S.S.Razavipour

    2012-01-01

    Solid-state fuel ignition was given by Chu and Bobin according to the hydrodynamic theory at x =0 qualitatively.A high threshold energy flux density,i.e.,E* =4.3 x 1012 J/m2,has been reached.Recently,fast ignition by employing clean petawatt-picosecond laser pulses was performed.The anomalous phenomena were observed to be based on suppression of prepulses.The accelerated plasma block was used to ignite deuterium-tritium fuel at solid-state density.The detailed analysis of the thermonuclear wave propagation was investigated.Also the fusion conditions at x ≠ 0 layers were clarified by exactly solving hydrodynamic equations for plasma block ignition.In this paper,the applied physical mechanisms are determined for nonlinear force laser driven plasma blocks,thermonuclear reaction,heat transfer,electron-ion equilibration,stopping power of alpha particles,bremsstrahlung,expansion,density dependence,and fluid dynamics.New ignition conditions may be obtained by using temperature equations,including thc dcnsity profile that is obtained by the continuity equation and expansion velocity.The density is only a function of x and independent of time.The ignition energy flux density,E*t,for the x ≠ 0 layers is 1.95 × 1012 J/m2.Thus threshold ignition energy in comparison with that at x =0 layers would be reduced to less than 50 percent.

  2. LIF measurements for validation of collisional-radiative modelling of atomic helium in the edge of a fusion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Krychowiak, M; Koenig, R; Wolf, R; Klinger, T [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Greifswald (Germany); Mertens, Ph; Schweer, B; Brezinsek, S; Schmitz, O; Samm, U [Institut fuer Energieforschung (Plasmaphysik), FZ Juelich, EURATOM Association, TEC, Juelich (Germany); Brix, M, E-mail: maciej.krychowiak@ipp.mpg.d [UKAEA, JET-Experimental Department, EURATOM Association, Culham Science Centre, Abingdon, Oxfordshire, OX14 3DB (United Kingdom)

    2010-05-01

    Local values of the electron density and temperature in the edge of a fusion plasma can be derived with high space and time resolution by the use of line radiation of atomic helium beams. The accuracy of this method is mainly limited by the uncertainties in the collisional-radiative (CR) model which is needed in order to obtain both plasma parameters from the measured relative intensities of atomic helium lines. Laser-induced fluorescence spectroscopy on a thermal helium beam in the edge plasma of the tokamak TEXTOR in Juelich was applied to validate the CR model of helium. By use of a high-power, pulsed laser system (a dye laser pumped by an excimer laser) several laser excitation schemes starting from the n=2 levels have been tried. The fluorescence light was observed at the laser wavelength and elsewhere in the spectrum providing information on population densities of initial levels as well as on collisional population transfer between excited levels. This paper summarises the results of the measurements, showing principal limits and possible improvements of this experimental validation method of the CR model of the diagnostic helium beam.

  3. LIF measurements for validation of collisional-radiative modelling of atomic helium in the edge of a fusion plasma

    Science.gov (United States)

    Krychowiak, M.; Mertens, Ph; König, R.; Schweer, B.; Brezinsek, S.; Schmitz, O.; Brix, M.; Samm, U.; Wolf, R.; Klinger, T.

    2010-05-01

    Local values of the electron density and temperature in the edge of a fusion plasma can be derived with high space and time resolution by the use of line radiation of atomic helium beams. The accuracy of this method is mainly limited by the uncertainties in the collisional-radiative (CR) model which is needed in order to obtain both plasma parameters from the measured relative intensities of atomic helium lines. Laser-induced fluorescence spectroscopy on a thermal helium beam in the edge plasma of the tokamak TEXTOR in Jülich was applied to validate the CR model of helium. By use of a high-power, pulsed laser system (a dye laser pumped by an excimer laser) several laser excitation schemes starting from the n=2 levels have been tried. The fluorescence light was observed at the laser wavelength and elsewhere in the spectrum providing information on population densities of initial levels as well as on collisional population transfer between excited levels. This paper summarises the results of the measurements, showing principal limits and possible improvements of this experimental validation method of the CR model of the diagnostic helium beam.

  4. Expansion of a plasma across a transverse magnetic field in a negative hydrogen ion source for fusion

    Science.gov (United States)

    Fantz, Ursel; Schiesko, Loic; Wünderlich, Dirk

    2012-10-01

    Negative ion sources are a key component of the neutral beam injection systems for the international fusion experiment ITER. To achieve the required ion current of 40 A at a tolerable amount of co-extracted electrons (electron to ion ratio below one) the source is separated into a plasma generation region and an expansion chamber equipped with a magnetic filter field (up to 10 mT). The field is needed for: (1) cooling the electrons down and thus minimize the H^- destruction by collisions, (2) to reduce the co-extracted electron current, and (3) to enhance the extraction probability for the surface produced negative ions. The area of the ITER source will be approximately 1m width and 2 m height, the IPP prototype source is a 1/8-size source. The recently installed flexible magnetic filter frame allows for systematic filter field studies (strength, position, polarity). Two Langmuir probes have been used to measure the plasma parameters simultaneously in axial direction. The profiles in the upper and lower part of the expansion chamber show beside the expected electron temperature and density decrease a drop in the plasma potential and a drift depending on the polarity, which vanishes when removing the filter field. The data interpretation is supported by modeling activities.

  5. Using VISAR to assess the M-band isotropy in hohlraums

    Science.gov (United States)

    Lanier, N. E.; Kline, J. L.; Morton, J.

    2016-11-01

    In laser based radiation flow experiments, drive variability can often overwhelm the physics sensitivity that one seeks to quantify. Hohlraums can help by providing a more symmetrized, Planckian-like source. However, at higher temperatures, the hohlraum's actual emission can deviate significantly from a truly blackbody, Lambertian source. At the National Ignition Facility (NIF), Dante provides the best quantification of hohlraum output. Unfortunately, limited diagnostic access coupled with NIF's natural symmetry does not allow for Dante measurements at more than two angles. As part of the CEPHEUS campaign on NIF, proof-of-principle experiments to better quantify the gold M-band isotropy were conducted. These experiments positioned beryllium/aluminum mirrors at differing angles, offset from the hohlraum. Filtering removes the thermal emission of the hohlraum and the remaining M-band radiation is preferentially absorbed in the aluminum layer. The subsequent hydrodynamic motion is measured via VISAR. Although indirect, this M-band measurement can be made at any angle.

  6. Frontiers in fusion research

    CERN Document Server

    Kikuchi, Mitsuru

    2011-01-01

    Frontiers in Fusion Research provides a systematic overview of the latest physical principles of fusion and plasma confinement. It is primarily devoted to the principle of magnetic plasma confinement, that has been systematized through 50 years of fusion research. Frontiers in Fusion Research begins with an introduction to the study of plasma, discussing the astronomical birth of hydrogen energy and the beginnings of human attempts to harness the Sun's energy for use on Earth. It moves on to chapters that cover a variety of topics such as: * charged particle motion, * plasma kinetic theory, *

  7. Vlasov-Fokker-Planck modeling of magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Alexander [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-08-01

    Understanding the magnetic fields that can develop in high-power-laser interactions with solid-density plasma is important because such fields significantly modify both the magnitude and direction of electron heat fluxes. The dynamics of such fields evidently have consequences for inertial fusion energy applications, as the coupling of the laser beams with the walls or pellet and the development of temperature inhomogeneities are critical to the uniformity of the implosion and potentially the success of, for example, the National Ignition Facility. To study these effects, we used the code Impacta, a two-dimensional, fully implicit, Vlasov-Fokker-Planck code with self-consistent magnetic fields and a hydrodynamic ion model, designed for nanosecond time-scale laser-plasma interactions. Heat-flux effects in Ohm’s law under non-local conditions was investigated; physics that is not well captured by standard numerical models but is nevertheless important in fusion-related scenarios. Under such conditions there are numerous interesting physical effects, such as collisional magnetic instabilities, amplification of magnetic fields, re-emergence of non-locality through magnetic convection, and reconnection of magnetic field lines and redistribution of thermal energy. In this project highlights included the first full scale kinetic simulations of a magnetized hohlraum [Joglekar 2016] and the discovery of a new magnetic reconnection mechanism [Joglekar 2014] as well as a completed PhD thesis and the production of a new code for Inertial Fusion research.

  8. BigFoot, a program to reduce risk for indirect drive laser fusion

    Science.gov (United States)

    Thomas, Cliff

    2016-10-01

    The conventional approach to inertial confinement fusion (ICF) is to maximize compressibility, or, total areal density. To achieve high convergence (40), the laser pulse is shaped to launch a weak first shock, which is followed in turn by 2-3 stronger shocks. Importantly, this has an outsized effect on integrated target physics, as the time it takes the shocks to transit the shell is related to hohlraum wall motion and filling, and can contribute to difficulties achieving an implosion that is fast, tunable, and/or predictable. At its outset, this approach attempts to predict the tradeoff in capsule and hohlraum physics in a case that is challenging, and assumes the hotspot can still reach the temperature and density necessary to self-heat (4-5 keV and 0.1-0.2 g/cm2, respectively). Here, we consider an alternate route to fusion ignition, for which the benefits of predictability, control, and coupling could exceed the benefits of convergence. In this approach we avoid uncertainty, and instead, seek a target that is predictable. To simplify hohlraum physics and limit wall motion we keep the implosion time short (6-7 ns), and design the target to avoid laser-plasma instabilities. Whereas the previous focus was on density, it is now on making a 1D hotspot at low convergence (20) that is robust with respect to alpha heating (5-6 keV, and 0.2-0.3 g/cm2) . At present, we estimate the tradeoff between convergence and control is relatively flat, and advantages in coupling enable high velocity (450-500 um/ns) and high yield (1E17). Were the