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Sample records for fast ion driven

  1. Assessment of Potential for Ion Driven Fast Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Logan, B. Grant; Bangerter, Roger O.; Callahan, Debra A.; Tabak,Max; Roth, Markus; Perkins, L. John; Caporaso, George

    2005-05-01

    Critical issues and ion beam requirements are explored for fast ignition using ion beams to provide fuel compression using indirect drive and to provide separate short pulse ignition heating using direct drive. Several ion species with different hohlraum geometries are considered for both accelerator-produced and laser-produced ion ignition beams. Ion-driven fast ignition targets are projected to have modestly higher gains than with conventional heavy-ion fusion, and may offer some other advantages for target fabrication and for use of advanced fuels. However, much more analysis and experiments are needed before conclusions can be drawn regarding the feasibility for meeting the ion beam transverse and longitudinal emittances, focal spots, pulse lengths, and target stand-off distances required for ion-driven fast ignition.

  2. Assessment of Potential for Ion Driven Fast Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Logan, B. Grant; Bangerter, Roger O.; Callahan, Debra A.; Tabak, Max; Roth, Markus; Perkins, L. John; Caporaso, George

    2004-12-01

    Critical issues and ion beam requirements are explored for fast ignition using ion beams to provide fuel compression using indirect drive and to provide separate short pulse ignition heating using direct drive. Several ion species with different hohlraum geometries are considered for both accelerator-produced and laser-produced ion ignition beams. Ion-driven fast ignition targets are projected to have modestly higher gains than with conventional heavy-ion fusion, and may offer some other advantages for target fabrication and for use of advanced fuels. However, much more analysis and experiments are needed before conclusions can be drawn regarding the feasibility for meeting the ion beam transverse and longitudinal emittances, focal spots, pulse lengths, and target standoff distances required for ion-driven fast ignition.

  3. Magnetic Configuration Effects on Fast Ion Losses Induced by Fast Ion Driven Toroidal Alfven Eigenmodes in the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K. [Nagoya University, Japan; Isobe, M. [National Institute for Fusion Science, Toki, Japan; Watanabe, F. [Kyoto University, Japan; Spong, Donald A [ORNL; Shimizu, A. [National Institute for Fusion Science, Toki, Japan; Osakabe, M. [National Institute for Fusion Science, Toki, Japan; Ohdachi, S. [National Institute for Fusion Science, Toki, Japan; Sakakibara, S. [National Institute for Fusion Science, Toki, Japan

    2012-01-01

    Beam-ion losses induced by fast-ion-driven toroidal Alfven eigenmodes (TAE) were measured with a scintillator-based lost fast-ion probe (SLIP) in the large helical device (LHD). The SLIP gave simultaneously the energy E and the pitch angle chi = arccos(v(parallel to)/v) distribution of the lost fast ions. The loss fluxes were investigated for three typical magnetic configurations of R{sub ax{_}vac} = 3.60 m, 3.75 m, and 3.90 m, where R{sub ax{_}vac} is the magnetic axis position of the vacuum field. Dominant losses induced by TAEs in these three configurations were observed in the E/chi regions of 50 similar to 190 keV/40 degrees, 40 similar to 170 keV/25 degrees, and 30 similar to 190 keV/30 degrees, respectively. Lost-ion fluxes induced by TAEs depend clearly on the amplitude of TAE magnetic fluctuations, R{sub ax{_}vac} and the toroidal field strength B{sub t}. The increment of the loss fluxes has the dependence of (b{sub TAE}/B{sub t}){sup s}. The power s increases from s = 1 to 3 with the increase of the magnetic axis position in finite beta plasmas.

  4. Magnetic Configuration Effects on Fast Ion Losses Induced by Fast Ion Driven Toroidal Alfv~n Eigenmodes in the Large Helical Device

    Institute of Scientific and Technical Information of China (English)

    K. OGAWA; M. ISOBE; K. TOI; F. WATANABE; D. A. SPONG; A. SHIMIZU; M. OSAKABE; D. S. DARROW; S. OHDACHI; S. SAKAKIBARA; LHD Experiment -Group

    2012-01-01

    Beam-ion losses induced by fast-ion-driven toroidal Alfven eigenmodes (TAE) were measured with a scintillator-based lost fast-ion probe (SLIP) in the large helical device (LHD). The SLIP gave simultaneously the energy E and the pitch angle X=arccos(v///v) distribution of the lost fast ions. The loss fluxes were investigated for three typical magnetic configurations of Rax-vac=3.60 m, 3.75 m. and 3.90 m, where Rax-vac is the magnetic axis position of the vacuum field. Dominant losses induced by TAEs in these three configurations were observed in the E/X regions of 50-190 keV/40°, 40-170 keV/25°, and 30-190 keV/30°, respectively. Lost-ion fluxes induced by TAEs depend clearly on the amplitude of TAE magnetic fluctuations, Rax-vac and the toroidal field strength Bt. The increment of the loss fluxes has the dependence of (bTAE/Bt)s. The power s increases from s = 1 to 3 with the increase of the magnetic axis position in finite beta plasmas.

  5. Simulation of fast-ion-driven Alfvén eigenmodes on the Experimental Advanced Superconducting Tokamak

    Science.gov (United States)

    Hu, Youjun; Todo, Y.; Pei, Youbin; Li, Guoqiang; Qian, Jinping; Xiang, Nong; Zhou, Deng; Ren, Qilong; Huang, Juan; Xu, Liqing

    2016-02-01

    Kinetic-MHD hybrid simulations are carried out to investigate possible fast-ion-driven modes on the Experimental Advanced Superconducting Tokamak. Three typical kinds of fast-ion-driven modes, namely, toroidicity-induced Alfvén eigenmodes, reversed shear Alfvén eigenmodes, and energetic-particle continuum modes, are observed simultaneously in the simulations. The simulation results are compared with the results of an ideal MHD eigenvalue code, which shows agreement with respect to the mode frequency, dominant poloidal mode numbers, and radial location. However, the modes in the hybrid simulations take a twisted structure on the poloidal plane, which is different from the results of the ideal MHD eigenvalue code. The twist is due to the radial phase variation of the eigenfunction, which may be attributed to the non-perturbative kinetic effects of the fast ions. By varying the stored energy of fast ions to change the fast ion drive in the simulations, it is demonstrated that the twist (i.e., the radial phase variation) is positively correlated with the fast ion drive.

  6. Energetic-particle-driven instabilities and induced fast-ion transport in a reversed field pinch

    Science.gov (United States)

    Lin, Liang

    2013-10-01

    Multiple bursty energetic-particle (EP) modes with fishbone-like structures are observed during 1 MW tangential neutral-beam injection into MST reversed field pinch (RFP) plasmas. The distinguishing features of the RFP, including large magnetic shear (tending to add stability) and weak toroidal magnetic field (leading to large fast ion beta and stronger drive), provide a complementary environment to tokamak and stellarator configurations for exploring basic understanding of these instabilities. Detailed measurements of the EP mode characteristics and temporal-spatial dynamics reveal their influence on fast ion transport and interaction with global tearing modes. Internal magnetic field fluctuations associated with the EP modes are directly observed for the first time by Faraday-effect polarimetry (frequency ~ 90 kHz and amplitude ~ 2 G). Simultaneously measured density fluctuations exhibit a dynamically evolving and asymmetric spatial structure that peaks near the core where fast ions reside and shifts outward as the instability evolves. Furthermore, the EP mode frequencies appear at ~k∥VA , consistent with continuum modes destabilized by strong drive. The fast-ion temporal dynamics, measured by a neutral particle analyzer, resemble a classical predator-prey relaxation oscillation. It contains a slow-growing phase arising from the beam fueling followed by a rapid drop (~ 15 %) when the EP modes peak, indicating the fluctuation-induced transport maintains a stiff fast-ion density profile. The inferred transport rate is strongly enhanced (× 2) with the onset of multiple nonlinearly-interacting EP modes. The fast ions also impact global tearing modes, reducing their amplitudes by up to 65%. This mode reduction is lessened following the EP-bursts, further evidence for fast ion redistribution that weakens the suppression mechanism. Possible tearing mode suppression mechanisms will be discussed. Work supported by US DoE.

  7. Ion acceleration in non-equilibrium plasmas driven by fast drifting electron

    Energy Technology Data Exchange (ETDEWEB)

    Castro, G. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Di Bartolo, F., E-mail: fdibartolo@unime.it [Università di Messina, V.le F. Stagno D’Alcontres 31, 98166, Messina (Italy); Gambino, N. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Metodologie Fisiche e Chimiche per L’ingegneria, Viale A.Doria 6, 95125 Catania (Italy); Mascali, D. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CSFNSM, Viale A. Doria 6, 95125 Catania (Italy); Romano, F.P. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CNR-IBAM Via Biblioteca 4, 95124 Catania (Italy); Anzalone, A.; Celona, L.; Gammino, S. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Di Giugno, R. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Lanaia, D. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Miracoli, R. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Serafino, T. [CSFNSM, Viale A. Doria 6, 95125 Catania (Italy); Tudisco, S. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CSFNSM, Viale A. Doria 6, 95125 Catania (Italy)

    2013-05-01

    We hereby present results on ion acceleration mechanisms in non equilibrium plasmas generated by microwaves or high intensity laser pulses. Experiments point out that in magnetized plasmas X–B conversion takes place for under resonance values of the magnetic field, i.e. an electromagnetic mode is converted into an electrostatic wave. The strong self-generated electric field, of the order of 10{sup 7} V/m, causes a E × B drift which accelerates both ions and electrons, as it is evident by localized sputtering in the plasma chamber. These fields are similar (in magnitude) to the ones obtainable in laser generated plasmas at intensity of 10{sup 12} W/cm{sup 2}. In this latter case, we observe that the acceleration mechanism is driven by electrons drifting much faster than plasma bulk, thus generating an extremely strong electric field ∼10{sup 7} V/m. The two experiments confirm that ions acceleration at low energy is possible with table-top devices and following complementary techniques: i.e. by using microwave-driven (producing CW beams) plasmas, or non-equilibrium laser-driven plasmas (producing pulsed beams). Possible applications involve ion implantation, materials surface modifications, ion beam assisted lithography, etc.

  8. New methods for high current fast ion beam production by laser-driven acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Margarone, D.; Krasa, J.; Prokupek, J.; Velyhan, A.; Laska, L.; Jungwirth, K.; Mocek, T.; Korn, G.; Rus, B. [Institute of Physics, ASCR, v.v.i., PALS Centre, Prague (Czech Republic); Torrisi, L.; Gammino, S.; Cirrone, P.; Cutroneo, M.; Romano, F. [INFN-Laboratori Nazionali del Sud, Catania, Messina University (Italy); Picciotto, A.; Serra, E. [Fondazione Bruno Kessler - IRST, Trento (Italy); Giuffrida, L. [CELIA, Centre Lasers Intenses et Applications (France); Mangione, A. [ITA - Istituto Tecnologie Avanzate, Trapani (Italy); Rosinski, M.; Parys, P. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); and others

    2012-02-15

    An overview of the last experimental campaigns on laser-driven ion acceleration performed at the PALS facility in Prague is given. Both the 2 TW, sub-nanosecond iodine laser system and the 20 TW, femtosecond Ti:sapphire laser, recently installed at PALS, are used along our experiments performed in the intensity range 10{sup 16}-10{sup 19} W/cm{sup 2}. The main goal of our studies was to generate high energy, high current ion streams at relatively low laser intensities. The discussed experimental investigations show promising results in terms of maximum ion energy and current density, which make the laser-accelerated ion beams a candidate for new-generation ion sources to be employed in medicine, nuclear physics, matter physics, and industry.

  9. New methods for high current fast ion beam production by laser-driven accelerationa)

    Science.gov (United States)

    Margarone, D.; Krasa, J.; Prokupek, J.; Velyhan, A.; Torrisi, L.; Picciotto, A.; Giuffrida, L.; Gammino, S.; Cirrone, P.; Cutroneo, M.; Romano, F.; Serra, E.; Mangione, A.; Rosinski, M.; Parys, P.; Ryc, L.; Limpouch, J.; Laska, L.; Jungwirth, K.; Ullschmied, J.; Mocek, T.; Korn, G.; Rus, B.

    2012-02-01

    An overview of the last experimental campaigns on laser-driven ion acceleration performed at the PALS facility in Prague is given. Both the 2 TW, sub-nanosecond iodine laser system and the 20 TW, femtosecond Ti:sapphire laser, recently installed at PALS, are used along our experiments performed in the intensity range 1016-1019 W/cm2. The main goal of our studies was to generate high energy, high current ion streams at relatively low laser intensities. The discussed experimental investigations show promising results in terms of maximum ion energy and current density, which make the laser-accelerated ion beams a candidate for new-generation ion sources to be employed in medicine, nuclear physics, matter physics, and industry.

  10. New methods for high current fast ion beam production by laser-driven acceleration.

    Science.gov (United States)

    Margarone, D; Krasa, J; Prokupek, J; Velyhan, A; Torrisi, L; Picciotto, A; Giuffrida, L; Gammino, S; Cirrone, P; Cutroneo, M; Romano, F; Serra, E; Mangione, A; Rosinski, M; Parys, P; Ryc, L; Limpouch, J; Laska, L; Jungwirth, K; Ullschmied, J; Mocek, T; Korn, G; Rus, B

    2012-02-01

    An overview of the last experimental campaigns on laser-driven ion acceleration performed at the PALS facility in Prague is given. Both the 2 TW, sub-nanosecond iodine laser system and the 20 TW, femtosecond Ti:sapphire laser, recently installed at PALS, are used along our experiments performed in the intensity range 10(16)-10(19) W∕cm(2). The main goal of our studies was to generate high energy, high current ion streams at relatively low laser intensities. The discussed experimental investigations show promising results in terms of maximum ion energy and current density, which make the laser-accelerated ion beams a candidate for new-generation ion sources to be employed in medicine, nuclear physics, matter physics, and industry.

  11. Fast particle-driven ion cyclotron emission (ICE) in tokamak plasmas and the case for an ICE diagnostic in ITER

    CERN Document Server

    McClements, K G; Dendy, R O; Carbajal, L; Chapman, S C; Cook, J W S; Harvey, R W; Heidbrink, W W; Pinches, S D

    2014-01-01

    Fast particle-driven waves in the ion cyclotron frequency range (ion cyclotron emission or ICE) have provided a valuable diagnostic of confined and escaping fast ions in many tokamaks. This is a passive, non-invasive diagnostic that would be compatible with the high radiation environment of deuterium-tritium plasmas in ITER, and could provide important information on fusion {\\alpha}-particles and beam ions in that device. In JET, ICE from confined fusion products scaled linearly with fusion reaction rate over six orders of magnitude and provided evidence that {\\alpha}-particle confinement was close to classical. In TFTR, ICE was observed from super-Alfv\\'enic {\\alpha}-particles in the plasma edge. The intensity of beam-driven ICE in DIII-D is more strongly correlated with drops in neutron rate during fishbone excitation than signals from more direct beam ion loss diagnostics. In ASDEX Upgrade ICE is produced by both super-Alfv\\'enic DD fusion products and sub-Alfv\\'enic deuterium beam ions.

  12. A Novel Data-Driven Fast Capacity Estimation of Spent Electric Vehicle Lithium-ion Batteries

    Directory of Open Access Journals (Sweden)

    Caiping Zhang

    2014-12-01

    Full Text Available Fast capacity estimation is a key enabling technique for second-life of lithium-ion batteries due to the hard work involved in determining the capacity of a large number of used electric vehicle (EV batteries. This paper tries to make three contributions to the existing literature through a robust and advanced algorithm: (1 a three layer back propagation artificial neural network (BP ANN model is developed to estimate the battery capacity. The model employs internal resistance expressing the battery’s kinetics as the model input, which can realize fast capacity estimation; (2 an estimation error model is established to investigate the relationship between the robustness coefficient and regression coefficient. It is revealed that commonly used ANN capacity estimation algorithm is flawed in providing robustness of parameter measurement uncertainties; (3 the law of large numbers is used as the basis for a proposed robust estimation approach, which optimally balances the relationship between estimation accuracy and disturbance rejection. An optimal range of the threshold for robustness coefficient is also discussed and proposed. Experimental results demonstrate the efficacy and the robustness of the BP ANN model together with the proposed identification approach, which can provide an important basis for large scale applications of second-life of batteries.

  13. Materials analysis fast ions

    CERN Document Server

    Denker, A; Rauschenberg, J; Röhrich, J; Strub, E

    2006-01-01

    Materials analysis with ion beams exploits the interaction of ions with the electrons and nuclei in the sample. Among the vast variety of possible analytical techniques available with ion beams we will restrain to ion beam analysis with ion beams in the energy range from one to several MeV per mass unit. It is possible to use either the back-scattered projectiles (RBS – Rutherford Back Scattering) or the recoiled atoms itself (ERDA – Elastic Recoil Detection Analysis) from the elastic scattering processes. These techniques allow the simultaneous and absolute determination of stoichiometry and depth profiles of the detected elements. The interaction of the ions with the electrons in the sample produces holes in the inner electronic shells of the sample atoms, which recombine and emit X-rays characteristic for the element in question. Particle Induced X-ray Emission (PIXE) has shown to be a fast technique for the analysis of elements with an atomic number above 11.

  14. Faraday-cup-type lost fast ion detector on Heliotron J

    Science.gov (United States)

    Yamamoto, S.; Ogawa, K.; Isobe, M.; Darrow, D. S.; Kobayashi, S.; Nagasaki, K.; Okada, H.; Minami, T.; Kado, S.; Ohshima, S.; Weir, G. M.; Nakamura, Y.; Konoshima, S.; Kemmochi, N.; Ohtani, Y.; Mizuuchi, T.

    2016-11-01

    A Faraday-cup type lost-fast ion probe (FLIP) has been designed and installed in Heliotron J for the purpose of the studies of interaction between fast ions and MHD instabilities. The FLIP can measure the co-going fast ions whose energy is in the range of 1.7-42.5 keV (proton) and pitch angle of 90∘-140∘, especially for fast ions having the injection energy of neutral beam injection (NBI). The FLIP successfully measured the re-entering passing ions and trapped lost-fast ions caused by fast-ion-driven energetic particle modes in NBI heated plasmas.

  15. Faraday-cup-type lost fast ion detector on Heliotron J.

    Science.gov (United States)

    Yamamoto, S; Ogawa, K; Isobe, M; Darrow, D S; Kobayashi, S; Nagasaki, K; Okada, H; Minami, T; Kado, S; Ohshima, S; Weir, G M; Nakamura, Y; Konoshima, S; Kemmochi, N; Ohtani, Y; Mizuuchi, T

    2016-11-01

    A Faraday-cup type lost-fast ion probe (FLIP) has been designed and installed in Heliotron J for the purpose of the studies of interaction between fast ions and MHD instabilities. The FLIP can measure the co-going fast ions whose energy is in the range of 1.7-42.5 keV (proton) and pitch angle of 90(∘)-140(∘), especially for fast ions having the injection energy of neutral beam injection (NBI). The FLIP successfully measured the re-entering passing ions and trapped lost-fast ions caused by fast-ion-driven energetic particle modes in NBI heated plasmas.

  16. Ion Beam Driven Warm Dense Matter Experiments

    Science.gov (United States)

    Bieniosek, F. M.; Henestroza, E.; Leitner, M. A.; Lidia, S. M.; Logan, B. G.; More, R. M.; Ni, P. A.; Seidl, P. A.; Waldron, W. L.; Barnard, J. J.

    2008-11-01

    We report plans and experimental results in ion beam-driven warm dense matter (WDM) experiments. Initial experiments use a 0.3 MeV K+ beam from the NDCX-I accelerator. The WDM conditions are to be achieved by longitudinal and transverse neutralized drift compression to provide a hot spot on the target with a 1-mm beam spot size, and 2-ns pulse length. As a technique for heating matter to high energy density, intense ion beams can deliver precise and uniform beam energy deposition, in a relatively large sample size, and can heat any solid-phase target material. The range of the beams in solid targets is less than 1 micron, which can be lengthened by using reduced density porous targets. We have developed a WDM target chamber and target diagnostics including a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial experiments will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  17. Ion sound instability driven by ion beam

    CERN Document Server

    Koshkarov, O; Kaganovich, I D; Ilgisonis, V I

    2014-01-01

    In many natural and laboratory conditions, plasmas are often in the non-equilibrium state due to presence of stationary flows, when one particle species (or a special group, such as group of high energy particles, i.e. beam) is mowing with respect to the other plasma components. Such situations are common for a number of different plasma application such as diagnostics with emissive plasma probes, plasma electronics devices and electric propulsion devices. The presence of plasma flows often lead to the instabilities in such systems and subsequent development of large amplitude perturbations. The goal of this work is to develop physical insights and numerical tools for studies of stability of the excitation of the ion sound waves by the ion beam in the configuration similar to the plasma Pierce diode. This systems, in some limiting cases, reduce to mathematically similar equations originally proposed for Pierce instability. The finite length effect are crucial for this instability which generally belong to the...

  18. Fast scheme for generating quantum-interference states and G HZ state of N trapped ions

    Institute of Scientific and Technical Information of China (English)

    Zheng Xiao-Juan; Fang Mao-Fa; Liao Xiang-Ping; Cai Jian-Wu; Cao Shuai

    2007-01-01

    We propose a fast scheme to generate the quantum-interference states of N trapped ions. In the scheme the ions are driven by a standing-wave laser beam whose carrier frequency is tuned such that the ion transition can take place.We also propose a simple and fast scheme to produce the GHZ state of N hot trapped ions and this scheme is insensitive to the heating of vibrational motion, which is important from the viewpoint of decoherence.

  19. The Frankfurt RF-driven ion source

    CERN Document Server

    Beller, Peter; Klein, H; Maaser, A; Volk, K; Weber, M

    2000-01-01

    An RF-driven volume ion source based on the high efficiency ion source (HIEFS) has been developed at the Institut fuer Angewandte Physik in Frankfurt. The RF-driven ion source operates at a frequency of 3.5 MHz with a maximum duty factor of 10%. Using an 11 kW RF-amplifier a He sup + -beam with a current of 82 mA as well as an oxygen beam with a current of 39 mA and an O sup + -fraction of 90% could be extracted. Experiments were done to study the operating conditions of the ion source. For the working gases helium and oxygen the emission current density in dependence on several ion source parameters was investigated. Furthermore, the energy distribution of the electrons and ions in the plasma as well as the beam composition for several working gases were studied. This article will give a detailed description of the ion source and the experimental setup. In addition, various dependencies between the plasma parameters and the emission current density, the energy distribution of electrons and ions and the beam ...

  20. Anomalous Flattening of the Fast-Ion Profile during Alfvén-Eigenmode Activity

    Science.gov (United States)

    Heidbrink, W. W.; Gorelenkov, N. N.; Luo, Y.; van Zeeland, M. A.; White, R. B.; Austin, M. E.; Burrell, K. H.; Kramer, G. J.; Makowski, M. A.; McKee, G. R.; Nazikian, R.

    2007-12-01

    Neutral-beam injection into plasmas with negative central shear produces a rich spectrum of toroidicity-induced and reversed-shear Alfvén eigenmodes in the DIII-D tokamak. The first application of fast-ion Dα (FIDA) spectroscopy to Alfvén-eigenmode physics shows that the central fast-ion profile is anomalously flat in the inner half of the discharge. Neutron and equilibrium measurements corroborate the FIDA data. The current density driven by fast ions is also strongly modified. Calculations based on the measured mode amplitudes do not explain the observed fast-ion transport.

  1. Accelerated Ions from a Laser Driven Z-pinch

    CERN Document Server

    Helle, Michael H; Kaganovich, Dmitri; Chen, Yu-hsin; Palastro, John P; Ting, Antonio

    2015-01-01

    Intense laser acceleration of ions is inherently difficult due to the velocity mismatch between laser pulses moving at the speed of light and slowly moving massive ions. Instead of directly accelerating the ions, current approaches rely on TV/m laser fields to ionize and drive out electrons. The ions are then accelerated by the resulting electrostatic fields from charge separation. Here we report experimental and numerical acceleration of ions by means of laser driven Z-pinch exiting a sharp plasma interface. This is achieved by first driving a plasma wakefield in the self-modulated bubble regime. Cold return currents are generated to maintain quasi-neutrality of the plasma. The opposite current repel and form an axial fast current and a cylindrical-shell cold return current with a large (100 MG) azithmuthal field in between. These conditions produce a Z-pinch that compresses the fast electrons and ions on axis. If this process is terminated at a sharp plasma interface, a beam of ions are then accelerated in ...

  2. Fast Quantum Rabi Model with Trapped Ions

    Science.gov (United States)

    Moya-Cessa, Héctor M.

    2016-12-01

    We show how to produce a fast quantum Rabi model with trapped ions. Its importance resides not only in the acceleration of the phenomena that may be achieved with these systems, from quantum gates to the generation of nonclassical states of the vibrational motion of the ion, but also in reducing unwanted effects such as the decay of coherences that may appear in such systems.

  3. Fast ion extraction in laser isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Hazak, G.; Gell, Y.; Boneh, Y.; Goshen, S.

    1980-10-01

    An analysis of the E x B scheme for fast ion extraction in laser isotope separation is presented. Using an analytically solvable model and a numerical simulation we have found that the scheme can meet the rather severe time and space restrictions imposed by the large cross section for charge exchange.

  4. Intense laser driven collision-less shock and ion acceleration in magnetized plasmas

    Science.gov (United States)

    Mima, K.; Jia, Q.; Cai, H. B.; Taguchi, T.; Nagatomo, H.; Sanz, J. R.; Honrubia, J.

    2016-05-01

    The generation of strong magnetic field with a laser driven coil has been demonstrated by many experiments. It is applicable to the magnetized fast ignition (MFI), the collision-less shock in the astrophysics and the ion shock acceleration. In this paper, the longitudinal magnetic field effect on the shock wave driven by the radiation pressure of an intense short pulse laser is investigated by theory and simulations. The transition of a laminar shock (electro static shock) to the turbulent shock (electromagnetic shock) occurs, when the external magnetic field is applied in near relativistic cut-off density plasmas. This transition leads to the enhancement of conversion of the laser energy into high energy ions. The enhancement of the conversion efficiency is important for the ion driven fast ignition and the laser driven neutron source. It is found that the total number of ions reflected by the shock increases by six time when the magnetic field is applied.

  5. Parametric Dependence Of Fast-ion Transport Events On The National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, Erik; Gorelenkov, N. N.; Podesta, M.; Gerhardt, S. P.; Bell, R. E.; Diallo, A.; LeBlanc, B. [Princeton Plasma Physics Lab., NJ (United States); Bortolon, A. [Univ. of Tennessee, Knoxville, TN (United States)

    2014-03-31

    Neutral-beam heated tokamak plasmas commonly have more than one third of the plasma kinetic energy in the non-thermal energetic beam ion population. This population of fast ions heats the plasma, provides some of the current drive, and can affect the stability (positively or negatively) of magnetohydrodynamic instabilities. This population of energetic ions is not in thermodynamic equilibrium, thus there is free-energy available to drive instabilities, which may lead to redistribution of the fast ion population. Understanding under what conditions beam-driven instabilities arise, and the extent of the resulting perturbation to the fast ion population, is important for predicting and eventually demonstrating non-inductive current ramp-up and sustainment in NSTX-U, as well as the performance of future fusion plasma experiments such as ITER. This paper presents an empirical approach towards characterizing the stability boundaries for some common energetic-ion-driven instabilities seen on NSTX.

  6. Controlling fast transport of cold trapped ions

    CERN Document Server

    Walther, Andreas; Ruster, Thomas; Dawkins, Sam T; Ott, Konstantin; Hettrich, Max; Singer, Kilian; Schmidt-Kaler, Ferdinand; Poschinger, Ulrich

    2012-01-01

    We realize fast transport of ions in a segmented micro-structured Paul trap. The ion is shuttled over a distance of more than 10^4 times its groundstate wavefunction size during only 5 motional cycles of the trap (280 micro meter in 3.6 micro seconds). Starting from a ground-state-cooled ion, we find an optimized transport such that the energy increase is as low as 0.10 $\\pm$ 0.01 motional quanta. In addition, we demonstrate that quantum information stored in a spin-motion entangled state is preserved throughout the transport. Shuttling operations are concatenated, as a proof-of-principle for the shuttling-based architecture to scalable ion trap quantum computing.

  7. Advanced approaches to high intensity laser-driven ion acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Henig, Andreas

    2010-04-26

    Since the pioneering work that was carried out 10 years ago, the generation of highly energetic ion beams from laser-plasma interactions has been investigated in much detail in the regime of target normal sheath acceleration (TNSA). Creation of ion beams with small longitudinal and transverse emittance and energies extending up to tens of MeV fueled visions of compact, laser-driven ion sources for applications such as ion beam therapy of tumors or fast ignition inertial con finement fusion. However, new pathways are of crucial importance to push the current limits of laser-generated ion beams further towards parameters necessary for those applications. The presented PhD work was intended to develop and explore advanced approaches to high intensity laser-driven ion acceleration that reach beyond TNSA. In this spirit, ion acceleration from two novel target systems was investigated, namely mass-limited microspheres and nm-thin, free-standing diamond-like carbon (DLC) foils. Using such ultrathin foils, a new regime of ion acceleration was found where the laser transfers energy to all electrons located within the focal volume. While for TNSA the accelerating electric field is stationary and ion acceleration is spatially separated from laser absorption into electrons, now a localized longitudinal field enhancement is present that co-propagates with the ions as the accompanying laser pulse pushes the electrons forward. Unprecedented maximum ion energies were obtained, reaching beyond 0.5 GeV for carbon C{sup 6+} and thus exceeding previous TNSA results by about one order of magnitude. When changing the laser polarization to circular, electron heating and expansion were shown to be efficiently suppressed, resulting for the first time in a phase-stable acceleration that is dominated by the laser radiation pressure which led to the observation of a peaked C{sup 6+} spectrum. Compared to quasi-monoenergetic ion beam generation within the TNSA regime, a more than 40 times

  8. Photochronographic registration of fast light ions

    Science.gov (United States)

    Litvin, Dmitri N.; Lazarchuk, Valeri P.; Murugov, Vasili M.; Petrov, Sergei I.; Senik, Alexei V.

    1999-06-01

    A possibility of registration of fast ions (protons, alpha- particles) with the help of an X-ray streak camera is demonstrated. The spatial resolution of the device is 50 micrometer, the physical time resolution with the use of a CsJ-cathode is 7 ps. From (alpha) -emission a secondary electrons yield is determined of (eta) equals 8 el../part. The device sensitivity makes it possible to register separate (alpha) -particles and protons. On the basis of the device there have been elaborated techniques of spatial-spectral registering of radiation of fast ions emitted by laser thermonuclear targets. The techniques are destined to study processes of interaction of high-intensive laser radiation with an appliance Iskra-5 target.

  9. A fast feedback controlled magnetic drive for the ASDEX Upgrade fast-ion loss detectors

    Science.gov (United States)

    Ayllon-Guerola, J.; Gonzalez-Martin, J.; Garcia-Munoz, M.; Rivero-Rodriguez, J.; Herrmann, A.; Vorbrugg, S.; Leitenstern, P.; Zoletnik, S.; Galdon, J.; Garcia Lopez, J.; Rodriguez-Ramos, M.; Sanchis-Sanchez, L.; Dominguez, A. D.; Kocan, M.; Gunn, J. P.; Garcia-Vallejo, D.; Dominguez, J.

    2016-11-01

    A magnetically driven fast-ion loss detector system for the ASDEX Upgrade tokamak has been designed and will be presented here. The device is feedback controlled to adapt the detector head position to the heat load and physics requirements. Dynamic simulations have been performed taking into account effects such as friction, coil self-induction, and eddy currents. A real time positioning control algorithm to maximize the detector operational window has been developed. This algorithm considers dynamical behavior and mechanical resistance as well as measured and predicted thermal loads. The mechanical design and real time predictive algorithm presented here may be used for other reciprocating systems.

  10. Laser-driven Ion Acceleration using Nanodiamonds

    Science.gov (United States)

    D'Hauthuille, Luc; Nguyen, Tam; Dollar, Franklin

    2016-10-01

    Interactions of high-intensity lasers with mass-limited nanoparticles enable the generation of extremely high electric fields. These fields accelerate ions, which has applications in nuclear medicine, high brightness radiography, as well as fast ignition for inertial confinement fusion. Previous studies have been performed with ensembles of nanoparticles, but this obscures the physics of the interaction due to the wide array of variables in the interaction. The work presented here looks instead at the interactions of a high intensity short pulse laser with an isolated nanodiamond. Specifically, we studied the effect of nanoparticle size and intensity of the laser on the interaction. A novel target scheme was developed to isolate the nanodiamond. Particle-in-cell simulations were performed using the EPOCH framework to show the sheath fields and resulting energetic ion beams.

  11. Fast Ion Collective Thomson Scattering Diagnostic for ITER

    DEFF Research Database (Denmark)

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

    2008-01-01

    In the era of high power and burning plasma fusion experiments with significant populations of fast particles, the diagnosis of fast ion dynamics becomes an important topic. In ITER, populations of fast ions due to ICRH and NBI, as well as fusion born alphas will carry a significant fraction of t...

  12. Fast ion beam-plasma interaction system.

    Science.gov (United States)

    Breun, R A; Ferron, J R

    1979-07-01

    A device has been constructed for the study of the interaction between a fast ion beam and a target plasma of separately controllable parameters. The beam of either hydrogen or helium ions has an energy of 1-4 keV and a total current of 0.5-2 A. The beam energy and beam current can be varied separately. The ion source plasma is created by a pulsed (0.2-10-ms pulse length) discharge in neutral gas at up to 3 x 10(-3) Torr. The neutrals are pulsed into the source chamber, allowing the neutral pressure in the target region to remain less than 5 x 10(-5) Torr at a 2-Hz repetition rate. The creation of the source plasma can be described by a simple set of equations which predict optimum source design parameters. The target plasma is also produced by a pulsed discharge. Between the target and source chambers the beam is neutralized by electrons drawn from a set of hot filaments. Currently under study is an unstable wave in a field-free plasma excited when the beam velocity is nearly equal to the target electron thermal velocity (v(beam) approximately 3.5 x 10(7) cm/s, Te = 0.5 eV).

  13. Fast ion confinement and stability in a neutral beam injected reversed field pinch

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J. K.; Almagri, A. F.; Den Hartog, D. J.; Eilerman, S.; Forest, C. B.; Koliner, J. J.; Mirnov, V. V.; Morton, L. A.; Nornberg, M. D.; Parke, E.; Reusch, J. A.; Sarff, J. S.; Waksman, J. [University of Wisconsin, Madison, Wisconsin 53706 (United States); Belykh, V.; Davydenko, V. I.; Ivanov, A. A.; Polosatkin, S. V.; Tsidulko, Y. A. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation); Lin, L. [University of California, Los Angeles, California 90095 (United States); Liu, D. [University of California, Irvine, California 92697 (United States); and others

    2013-05-15

    The behavior of energetic ions is fundamentally important in the study of fusion plasmas. While well-studied in tokamak, spherical torus, and stellarator plasmas, relatively little is known in reversed field pinch plasmas about the dynamics of fast ions and the effects they cause as a large population. These studies are now underway in the Madison Symmetric Torus with an intense 25 keV, 1 MW hydrogen neutral beam injector (NBI). Measurements of the time-resolved fast ion distribution via a high energy neutral particle analyzer, as well as beam-target neutron flux (when NBI fuel is doped with 3–5% D{sub 2}) both demonstrate that at low concentration the fast ion population is consistent with classical slowing of the fast ions, negligible cross-field transport, and charge exchange as the dominant ion loss mechanism. A significant population of fast ions develops; simulations predict a super-Alfvénic ion density of up to 25% of the electron density with both a significant velocity space gradient and a sharp radial density gradient. There are several effects on the background plasma including enhanced toroidal rotation, electron heating, and an altered current density profile. The abundant fast particles affect the plasma stability. Fast ions at the island of the core-most resonant tearing mode have a stabilizing effect, and up to 60% reduction in the magnetic fluctuation amplitude is observed during NBI. The sharp reduction in amplitude, however, has little effect on the underlying magnetic island structure. Simultaneously, beam driven instabilities are observed as repetitive ∼50 μs bursts which coincide with fast particle redistribution; data indicate a saturated core fast ion density well below purely classical predictions.

  14. Fast ions and momentum transport in JET tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Salmi, A.

    2012-07-01

    Fast ions are an inseparable part of fusion plasmas. They can be generated using electromagnetic waves or injected into plasmas as neutrals to heat the bulk plasma and to drive toroidal rotation and current. In future power plants fusion born fast ions deliver the main heating into the plasma. Understanding and controlling the fast ions is of crucial importance for the operation of a power plant. Furthermore, fast ions provide ways to probe the properties of the thermal plasma and get insight of its confinement properties. In this thesis, numerical code packages are used and developed to simulate JET experiments for a range of physics issues related to fast ions. Namely, the clamping fast ion distribution at high energies with RF heating, fast ion ripple torque generation and the toroidal momentum transport properties using NBI modulation technique are investigated. Through a comparison of numerical simulations and the JET experimental data it is shown that the finite Larmor radius effects in ion cyclotron resonance heating are important and that they can prevent fast ion tail formation beyond certain energy. The identified mechanism could be used for tailoring the fast ion distribution in future experiments. Secondly, ASCOT simulations of NBI ions in a ripple field showed that most of the reduction of the toroidal rotation that has been observed in the JET enhanced ripple experiments could be attributed to fast ion ripple torque. Finally, fast ion torque calculations together with momentum transport analysis have led to the conclusion that momentum transport in not purely diffusive but that a convective component, which increases monotonically in radius, exists in a wide range of JET plasmas. Using parameter scans, the convective transport has been shown to be insensitive to collisionality and q-profile but to increase strongly against density gradient. (orig.)

  15. Fast-ion transport induced by Alfvén eigenmodes in the ASDEX Upgrade tokamak

    DEFF Research Database (Denmark)

    Garcia-Munoz, M.; Classen, I.G.J.; Geiger, B.

    2011-01-01

    A comprehensive suite of diagnostics has allowed detailed measurements of the Alfvén eigenmode (AE) spatial structure and subsequent fast-ion transport in the ASDEX Upgrade (AUG) tokamak [1]. Reversed shear Alfvén eigenmodes (RSAEs) and toroidal induced Alfvén eigenmodes (TAEs) have been driven u...

  16. Fast formation cycling for lithium ion batteries

    Science.gov (United States)

    An, Seong Jin; Li, Jianlin; Du, Zhijia; Daniel, Claus; Wood, David L.

    2017-02-01

    The formation process for lithium ion batteries typically takes several days or more, and it is necessary for providing a stable solid electrolyte interphase on the anode (at low potentials vs. Li/Li+) for preventing irreversible consumption of electrolyte and lithium ions. An analogous layer known as the cathode electrolyte interphase layer forms at the cathode at high potentials vs. Li/Li+. However, several days, or even up to a week, of these processes result in either lower LIB production rates or a prohibitively large size of charging-discharging equipment and space (i.e. excessive capital cost). In this study, a fast and effective electrolyte interphase formation protocol is proposed and compared with an Oak Ridge National Laboratory baseline protocol. Graphite, NMC 532, and 1.2 M LiPF6 in ethylene carbonate: diethyl carbonate were used as anodes, cathodes, and electrolytes, respectively. Results from electrochemical impedance spectroscopy show the new protocol reduced surface film (electrolyte interphase) resistances, and 1300 aging cycles show an improvement in capacity retention.

  17. Fast ion generation and runaway through magnetic reconnection events in MST

    Science.gov (United States)

    Kim, Jungha; Anderson, Jay; Capecchi, William; Bonofiglo, Phillip; Sears, Stephanie

    2016-10-01

    Fokker-Planck and full orbit modeling are used to investigate how global reconnection events in MST plasmas generate an anisotropic fast ion distribution. A multi-step process is hypothesized. First, thermal ions are heated by a perpendicular heating mechanism, possibly a stochastic process that relies on turbulent diffusion and strong radial electric fields, or ion cyclotron damping in the tearing-driven turbulent cascade. Second, a small fraction of the heated ions have sufficient speed to develop substantial guiding center drifts that are relatively immune to stochastic magnetic transport. In the RFP, these fast ion drift orbits are favorable to confinement. Finally, these fast ions are accelerated by a parallel inductive electric field (up to 80 V/m) associated with the abruptly changing magnetic equilibrium. This strong impulsive field does not include any magnetic-fluctuation-based contribution as experienced by thermal particles or electrons, which do not run away like fast ions. CQL3D, a Fokker-Planck solver, and RIO, a full orbit tracing code, are used to model this multi-step process that is responsible for anisotropy in fast ion distribution in MST. Work supported by US DOE. Supported by US DOE.

  18. Transfer ionization in collisions with a fast highly charged ion.

    Science.gov (United States)

    Voitkiv, A B

    2013-07-26

    Transfer ionization in fast collisions between a bare ion and an atom, in which one of the atomic electrons is captured by the ion whereas another one is emitted, crucially depends on dynamic electron-electron correlations. We show that in collisions with a highly charged ion a strong field of the ion has a very profound effect on the correlated channels of transfer ionization. In particular, this field weakens (strongly suppresses) electron emission into the direction opposite (perpendicular) to the motion of the ion. Instead, electron emission is redirected into those parts of the momentum space which are very weakly populated in fast collisions with low charged ions.

  19. Fast Ion Redistribution and Implications for the Hybrid Regime

    Energy Technology Data Exchange (ETDEWEB)

    Nazikian, R; Austin, M E; Budny, R V; Chu, M S; Heidbrink, W W; Makowski, M A; Petty, C C; Politzer, P A; Solomon, W M; Van Zeeland, M A

    2007-06-26

    Time dependent TRANSP analysis indicates that radial redistribution of fast ions is unlikely to affect the central current density in hybrid plasmas sufficient to raise q(0) above unity. The results suggest that some other mechanism other than fast ion transport must be involved in raising q(0) and preventing sawteeth in hybrid plasmas.

  20. Measurement and control of the fast ion redistribution on MAST

    CERN Document Server

    Turnyanskiy, M; Akers, R J; Cecconello, M; Keeling, D L; Kirk, A; Lake, R; Pinches, S D; Sangaroon, S; Wodniak, I

    2013-01-01

    Previous experiments on MAST and other tokamaks have indicated that the level of fast ion redistribution can exceed that expected from classical diffusion and that this level increases with beam power. In this paper we present a quantification of this effect in MAST plasmas using a recently commissioned scanning neutron camera. The observed fast ion diffusivity correlates with the amplitude of n=1 energetic particle modes, indicating that they are the probable cause of the non-classical fast ion diffusion in MAST. Finally, it will be shown that broadening the fast ion pressure profile by the application of neutral beam injection at an off-axis location can mitigate the growth of these modes and result in the classical fast ion behaviour

  1. Benchmark of MEGA Code on Fast Ion Pressure Profile in the Large Helical Device

    Science.gov (United States)

    Seki, Ryosuke; Todo, Yasushi; Suzuki, Yasuhiro; Osakabe, Masaki

    2016-10-01

    As the first step for the analyses of energetic particle driven instabilities in the Large Helical Device (LHD) including the collisions of fast ions and the neutral beam injection, MEGA code is benchmarked on the classical fast ion pressure profile using the temperature and density profiles measured in the LHD experiments. In this benchmark, the MHD equilibrium is calculated with HINT code, and the beam deposition profile is calculated with HFREYA code. Since the equilibrium is not axisymmetric in LHD, the accuracy of orbit tracing is important for fast ion analyses. In the slowing down process of the MEGA code, the guiding center equation is numerically solved using the 4th order Runge-Kutta method and the linear interpolation. MEGA code is benchmarked against the results of MORH code, in which the 6th order Runge-Kutta and the 4th order spline interpolation are used. In LHD, the position of the loss boundary of fast ion is important because there are many ``re-entering fast ions'' which re-enter in plasma after they have once passed out of plasma. The effects of the position of the loss boundary on the fast ion pressure profile will be discussed, and a preliminary result of Alfven eigenmodes will be presented.

  2. 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.

  3. Ultra Fast Shutter Driven by Pulsed High Current

    Institute of Scientific and Technical Information of China (English)

    Zeng Jiangtao; Sun Fengju; Qiu Aici; Yin Jiahui; Guo Jianming; Chen Yulan

    2005-01-01

    Radiation simulation utilizing plasma radiation sources (PRS) generates a large number of undesirable debris, which may damage the expensive diagnosing detectors. An ultra fast shutter (UFS) driven by pulsed high current can erect a physical barrier to the slowly moving debris after allowing the passage of X-ray photons. The UFS consists of a pair of thin metal foils twisting the parallel axes in a Nylon cassette, compressed with an outer magnetic field, generated from a fast capacitor bank, discharging into a single turn loop. A typical capacitor bank is of 7.5μF charging voltages varying from 30 kV to 45 kV, with corresponding currents of approximately 90kA to140 kA and discharging current periods of approximately 13.1 μs. A shutter closing time as fast as 38 microseconds has been obtained with an aluminium foil thickness of 100 micrometers and a cross-sectional area of 15 mm by 20 mm. The design, construction and the expressions of the valve-closing time of the UFS are presented along with the measured results of valve-closing velocities.

  4. Scintillator-based fast ion loss measurements in the EAST

    Science.gov (United States)

    Chang, J. F.; Isobe, M.; Ogawa, K.; Huang, J.; Wu, C. R.; Xu, Z.; Jin, Z.; Lin, S. Y.; Hu, L. Q.

    2016-11-01

    A new scintillator-based fast ion loss detector (FILD) has been installed on Experimental Advanced Superconducting Tokamak (EAST) to investigate the fast ion loss behavior in high performance plasma with neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH). A two dimensional 40 mm × 40 mm scintillator-coated (ZnS:Ag) stainless plate is mounted in the front of the detector, capturing the escaping fast ions. Photons from the scintillator plate are imaged with a Phantom V2010 CCD camera. The lost fast ions can be measured with the pitch angle from 60° to 120° and the gyroradius from 10 mm to 180 mm. This paper will describe the details of FILD diagnostic on EAST and describe preliminary measurements during NBI and ICRH heating.

  5. Global anomalous transport of ICRH- and NBI-heated fast ions

    Science.gov (United States)

    Wilkie, G. J.; Pusztai, I.; Abel, I.; Dorland, W.; Fülöp, T.

    2017-04-01

    By taking advantage of the trace approximation, one can gain an enormous computational advantage when solving for the global turbulent transport of impurities. In particular, this makes feasible the study of non-Maxwellian transport coupled in radius and energy, allowing collisions and transport to be accounted for on similar time scales, as occurs for fast ions. In this work, we study the fully-nonlinear ITG-driven trace turbulent transport of locally heated and injected fast ions. Previous results indicated the existence of MeV-range minorities heated by cyclotron resonance, and an associated density pinch effect. Here, we build upon this result using the t3core code to solve for the distribution of these minorities, consistently including the effects of collisions, gyrokinetic turbulence, and heating. Using the same tool to study the transport of injected fast ions, we contrast the qualitative features of their transport with that of the heated minorities. Our results indicate that heated minorities are more strongly affected by microturbulence than injected fast ions. The physical interpretation of this difference provides a possible explanation for the observed synergy when neutral beam injection (NBI) heating is combined with ion cyclotron resonance heating (ICRH). Furthermore, we move beyond the trace approximation to develop a model which allows one to easily account for the reduction of anomalous transport due to the presence of fast ions in electrostatic turbulence.

  6. A fast beam-ion instability

    Energy Technology Data Exchange (ETDEWEB)

    Stupakov, G.V. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    The ionization of residual gas by an electron beam in an accelerator generates ions that can resonantly couple to the beam through a wave propagating in the beam-ion system. Results of the study of a beam-ion instability are presented for a multi-bunch train taking into account the decoherence of ion oscillations due to the ion frequency spread and spatial variation of the ion frequency. It is shown that the combination of both effects can substantially reduce the growth rate of the instability. (author)

  7. Sources and detectors of fast ions for basic devices

    OpenAIRE

    Furno, Ivo; Fasoli, Ambrogio; Plyushchev, Gennady

    2009-01-01

    The physics of supra thermal test ions in turbulent plasmas can be conveniently studied in basic plasma physics devices, which allow high-resolution measurements of plasma and fast ion parameters and wave fields throughout the whole plasma cross-section. We describe recent advances in the development of an experimental setup consisting of a non-perturbative Li 6+ miniaturized ion source and a detector for the investigation of the interaction between supra thermal ions and drift/interchange–dr...

  8. Global anomalous transport of ICRH- and NBI-heated fast ions

    CERN Document Server

    Wilkie, George J; Abel, Ian G; Dorland, William; Fülöp, Tünde

    2016-01-01

    By taking advantage of the trace approximation, one can gain an enormous computational advantage when solving for the global turbulent transport of impurities. In particular, this makes feasible the study of non-Maxwellian transport coupled in radius and energy, allowing collisions and transport to be accounted for on similar time scales, as occurs for fast ions. In this work, we study the fully-nonlinear ITG-driven trace turbulent transport of locally heated and injected fast ions. Previous results indicated the existence of MeV-range minorities heated by cyclotron resonance, and an associated density pinch effect. Here, we build upon this result using the t3core code to solve for the distribution of these minorities, consistently including the effects of collisions, gyrokinetic turbulence, and heating. Using the same tool to study the transport of injected fast ions, we contrast the qualitative features of their transport with that of the heated minorities. Furthermore, we move beyond the trace approximatio...

  9. Simulation analysis for ion assisted fast ignition using structured targets

    Science.gov (United States)

    Sakagami, H.; Johzaki, T.; Sunahara, A.; Nagatomo, H.

    2016-05-01

    As the heating efficiency by fast electrons in the fast ignition scheme is estimated to be very low due to their large divergence angle and high energy. To mitigate this problem, low-density plastic foam, which can generate not only proton (H+) but also carbon (C6+) beams, can be introduced to currently used cone-guided targets and additional core heating by ions is expected. According to 2D PIC simulations, it is found that the ion beams also diverge by the static electric field and concave surface deformation. Thus structured targets are suggested to optimize ion beam characteristics, and their improvement and core heating enhancement by ion beams are confirmed.

  10. Data-driven execution of fast multipole methods

    KAUST Repository

    Ltaief, Hatem

    2013-09-17

    Fast multipole methods (FMMs) have O (N) complexity, are compute bound, and require very little synchronization, which makes them a favorable algorithm on next-generation supercomputers. Their most common application is to accelerate N-body problems, but they can also be used to solve boundary integral equations. When the particle distribution is irregular and the tree structure is adaptive, load balancing becomes a non-trivial question. A common strategy for load balancing FMMs is to use the work load from the previous step as weights to statically repartition the next step. The authors discuss in the paper another approach based on data-driven execution to efficiently tackle this challenging load balancing problem. The core idea consists of breaking the most time-consuming stages of the FMMs into smaller tasks. The algorithm can then be represented as a directed acyclic graph where nodes represent tasks and edges represent dependencies among them. The execution of the algorithm is performed by asynchronously scheduling the tasks using the queueing and runtime for kernels runtime environment, in a way such that data dependencies are not violated for numerical correctness purposes. This asynchronous scheduling results in an out-of-order execution. The performance results of the data-driven FMM execution outperform the previous strategy and show linear speedup on a quad-socket quad-core Intel Xeon system.Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

  11. Electromagnetically driven, fast opening and closing gas jet valve

    Science.gov (United States)

    Krishnan, Mahadevan; Elliott, Kristi Wilson; Geddes, C. G. R.; van Mourik, R. A.; Leemans, W. P.; Murphy, H.; Clover, M.

    2011-03-01

    The design and performance are presented of an electromagnetically driven gas valve [M. Krishnan, J. Wright, and T. Ma, Proceedings of the 13th Advanced Accelerator Concepts Workshop, Santa Cruz, CA, AIP Conf. Proc. No. 1086 (AIP, New York, 2008)] that opens in <100μs, closes in <500μs, and can operate at pressures of ˜1000psia to drive supersonic nozzles. Such a valve has applications to laser-plasma accelerators, where the fast opening and closing would allow sharper edges to the flow and also allow higher rep-rate operation without loading the vacuum chamber. The valve action is effected by a flyer plate accelerated by the electromagnetic impulse of a low inductance, spiral wound, strip-line coil driven by a capacitor. Gas flows out of the valve when the seal between this flyer plate and the valve seat is broken. The electromagnetic force greatly exceeds the restoring forces provided by a spring and the gas pressure against the valve seat. Piezoresistive sensor and laser interferometer measurements of flow show that the valve opens in ˜100μs for all pressures up to 800 psia. The closing time is 500μs, set by the spring constant and mass. The prototype valve has been operated with helium at 0.5 Hz and at 500 psia for ˜1 hour at a time with no cooling.

  12. Fast ion collective Thomson scattering diagnostic for ITER: Design elements

    DEFF Research Database (Denmark)

    Tsakadze, Erekle; Bindslev, Henrik; Korsholm, Søren Bang

    2008-01-01

    The proposed fast ion collective Thomson scattering (CTS) diagnostic system for ITER provides the unique capability of measuring the temporally and spatially resolved velocity distribution of the confined fast ions and fusion alpha particles in a burning ITER plasma. The present paper describes t...... in the studies, and new HFS receiver mock-up measurements are presented as well as neutron flux calculations of the influence of the increased slot height....

  13. Fast Tunable Microwave Devices Using Self-driven Plasma Instabilities

    Science.gov (United States)

    Biggs, David; Cappelli, Mark

    2016-10-01

    Tunable electromagnetic devices using plasmas are of interest for various applications such as high frequency communications and analog signal processing. At microwave frequencies of tens of gigahertz, low-pressure plasmas must be employed in order to avoid high wave damping from collisions. The drawback of low-pressure plasmas is that their diffusion timescales are long, on the order of hundreds of microseconds. Other mechanisms than diffusion must be employed to achieve fast tuning capabilities of these devices. One candidate mechanism is to use a self-driven plasma instability, which may allow for fast tuning of microwave resonant cavities. In this work, a microwave resonant cavity is studied consisting of a rectangular waveguide with two conducting posts spaced along the propagation direction to form a rectangular cavity. The cavity acts as a band pass filter and transmits microwave signals around its resonant frequency. Plasma may be introduced into the cavity between the conducting posts in order to change the refractive index and thus the resonant and transmission frequency of the device. The location of the plasma and its plasma density are important parameters in determining the resonant frequency, and both parameters are capable of being tuned with plasma instabilities. This work is supported by the Air Force Office of Scientific Research.

  14. Existence domains of slow and fast ion-acoustic solitons in two-ion space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Maharaj, S. K., E-mail: smaharaj@sansa.org.za [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200 (South Africa); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Robert Sobukwe Road, Bellville, 7535 (South Africa); Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)

    2015-03-15

    A study of large amplitude ion-acoustic solitons is conducted for a model composed of cool and hot ions and cool and hot electrons. Using the Sagdeev pseudo-potential formalism, the scope of earlier studies is extended to consider why upper Mach number limitations arise for slow and fast ion-acoustic solitons. Treating all plasma constituents as adiabatic fluids, slow ion-acoustic solitons are limited in the order of increasing cool ion concentrations by the number densities of the cool, and then the hot ions becoming complex valued, followed by positive and then negative potential double layer regions. Only positive potentials are found for fast ion-acoustic solitons which are limited only by the hot ion number density having to remain real valued. The effect of neglecting as opposed to including inertial effects of the hot electrons is found to induce only minor quantitative changes in the existence regions of slow and fast ion-acoustic solitons.

  15. Charge exchange spectroscopy as a fast ion diagnostic on TEXTORa)

    Science.gov (United States)

    Delabie, E.; Jaspers, R. J. E.; von Hellermann, M. G.; Nielsen, S. K.; Marchuk, O.

    2008-10-01

    An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for active spectroscopy, injected counter the direction in which fast ions injected by the first beam are circulating, we can simultaneously measure a fast ion tail on the blue wing of the Dα spectrum while the beam emission spectrum is Doppler shifted to the red wing. An analysis combining the two parts of the spectrum offers possibilities to improve the accuracy of the absolute (fast) ion density profiles. Fast beam modulation or passive viewing lines cannot be used for background subtraction on this diagnostic setup and therefore the background has to be modeled and fitted to the data together with a spectral model for the slowing down feature. The analysis of the fast ion Dα spectrum obtained with the new diagnostic is discussed.

  16. A new type of MHD activity in JET ICRF-only discharges with high fast-ion energy contents

    Energy Technology Data Exchange (ETDEWEB)

    Mantsinen, M.J. [JET Joint Undertaking, Abingdon, Oxfordshire (United Kingdom); Helsinki University of Technology, Association Euratom-Tekes (Finland); Sharapov, S.; Alper, B.; Gondhalekar, A.; McDonald, D.C. [JET Joint Undertaking, Abingdon, Oxfordshire (United Kingdom)

    2000-12-01

    The question of sawtooth stabilization at very high fast-ion energy contents has been addressed in discharges carried out in the JET tokamak with ion cyclotron resonance frequency (ICRF) heating and varying plasma density, controlled by deuterium gas puffs. In these experiments dramatic differences in the sawtooth behaviour have been observed. When the plasma density n{sub e} decreases below a certain threshold, the sawtooth frequency and the crash duration time increase by a factor of five. Since the fast-ion energy content increases with decreasing n{sub e} due to the inverse proportionality of the fast-ion slowing-down time on n{sub e}, the threshold in n{sub e} corresponds to a threshold in the fast-ion energy content. In the present experiments, this threshold is reached when the fast-ion energy contribution to the total plasma diamagnetic energy content becomes larger than 45%. The sawtooth activity with short sawtooth free period is accompanied by MHD activity, with a toroidal mode number n = 1 at frequencies between 55 and 65 kHz. This activity is interpreted as an energetic particle fishbone mode that is resonant with the ICRF-driven fast ions. The experimental results appear to be consistent with the stability diagram for sawtooth and fishbone modes (White 1989 Theory of Tokamak Plasmas (Amsterdam: North-Holland)), exploring the part of the diagram with a very large fast-ion population. (author)

  17. A new type of MHD activity in JET ICRF-only discharges with high fast-ion energy contents

    Energy Technology Data Exchange (ETDEWEB)

    Mantsinen, M.; Sharapov, S.; Alper, B. [and others

    2000-12-01

    The question of sawtooth stabilisation at very high fast ion energy contents has been addressed in discharges carried out in the JET tokamak with ion cyclotron resonance frequency (ICRF) heating and varying plasma density, controlled by deuterium gas puffs. In these experiments dramatic differences in the sawtooth behaviour have been observed. When the plasma density n{sub e} decreases below a certain threshold, the sawtooth frequency and the crash duration time increase by a factor of five. Since the fast-ion energy content increases with decreasing n{sub e} due to the inverse proportionality of the fast-ion slowing-down time on n{sub e}, the threshold in n{sub e} corresponds to a threshold in the fast ion energy content. In the present experiments, this threshold is reached when the fast ion energy contribution to the total plasma diamagnetic energy content becomes larger than 45%. The sawtooth activity with short sawtooth free period is accompanied by MHD activity, with a toroidal mode number n = 1 at frequencies between 55-65 kHz. This activity is interpreted as an energetic particle fishbone mode that is resonant with the ICRF-driven fast ions. The experimental results appear to be consistent with the stability diagram for sawtooth and fishbone modes [White, Theory of Tokamak Plasmas (North-Holland, Amsterdam, 1989)], exploring the part of the diagram with a very large fast ion population. (author)

  18. A new type of MHD activity in JET ICRF-only discharges with high fast-ion energy contents

    Science.gov (United States)

    Mantsinen, M. J.; Sharapov, S.; Alper, B.; Gondhalekar, A.; McDonald, D. C.

    2000-12-01

    The question of sawtooth stabilization at very high fast-ion energy contents has been addressed in discharges carried out in the JET tokamak with ion cyclotron resonance frequency (ICRF) heating and varying plasma density, controlled by deuterium gas puffs. In these experiments dramatic differences in the sawtooth behaviour have been observed. When the plasma density ne decreases below a certain threshold, the sawtooth frequency and the crash duration time increase by a factor of five. Since the fast-ion energy content increases with decreasing ne due to the inverse proportionality of the fast-ion slowing-down time on ne, the threshold in ne corresponds to a threshold in the fast-ion energy content. In the present experiments, this threshold is reached when the fast-ion energy contribution to the total plasma diamagnetic energy content becomes larger than 45%. The sawtooth activity with short sawtooth free period is accompanied by MHD activity, with a toroidal mode number n = 1 at frequencies between 55 and 65 kHz. This activity is interpreted as an energetic particle fishbone mode that is resonant with the ICRF-driven fast ions. The experimental results appear to be consistent with the stability diagram for sawtooth and fishbone modes (White 1989 Theory of Tokamak Plasmas (Amsterdam: North-Holland)), exploring the part of the diagram with a very large fast-ion population.

  19. RF Driven Multicusp H- Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Leung, K.N.; DeVries, G.J.; DiVergilio, W.F.; Hamm, R.W.; Hauck, C.A.; Kunkel, W.B.; McDonald, D.S.; Williams, M.D.

    1990-06-01

    An rf driven multicusp source capable of generating 1-ms H{sup -} beam pulses with a repetition rate as high as 150 Hz has been developed. This source can be operated with a filament or other types of starter. There is almost no lifetime limitation and a clean plasma can be maintained for a long period of operation. It is demonstrated that rf power as high as 25 kW could be coupled inductively to the plasma via a glass-coated copper-coil antenna. The extracted H{sup -} current density achieved is about 200 mA/cm{sup 2}.

  20. Glancing-angle scattering of fast ions at crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mannami, Michihiko; Narumi, Kazumasa; Katoh, Humiya; Kimura, Kenji [Kyoto Univ. (Japan). Faculty of Engineering

    1997-03-01

    Glancing angle scattering of fast ions from a single crystal surface is a novel technique to study ion-surface interaction. Results of recent studies of ion-surface interaction are reviewed for ions with velocities faster than the Fermi velocity of solid. For the ions with velocities less than the Fermi velocity of target valence electrons the ion-surface interaction shows a new aspect where only the valence electrons of target solid participate in the stopping processes. It will show that the position-dependent stopping power of a surface for these ions governed by the elastic collisions of valence electrons and the ions. A method is proposed from this position-dependent stopping power to derived the electron density distribution averaged over the plane parallel to the surface. (author)

  1. Ion beam driven HEDP experiments on NDCX

    Science.gov (United States)

    Bieniosek, F. M.; Henestroza, E.; Lidia, S.; More, R. M.; Ni, P. A.; Roy, P. K.; Seidl, P. A.; Barnard, J. J.

    2010-11-01

    Intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition, with the capability to heat volumetric samples of any solid-phase target material to high energy density. The WDM conditions are achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm. Initial experiments use a 0.3 MeV, 30-mA K^+ beam from the NDCX-I accelerator to heat foil targets such as Au, Pt, W, Al and Si. The NDCX-1 beam contains a low-intensity uncompressed pulse up to >10 μs of intensity ˜0.4 MW/cm^2, and a high-intensity compressed pulse (FWHM 2-3 ns and fluence ˜4 mJ). WDM experiments heat targets by both the compressed and uncompressed parts of the NDCX-I beam, and explore measurement of temperature, droplet formation and other target parameters. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 2-3 MeV lithium ion beam.

  2. First fast-ion D-alpha (FIDA) measurements and simulations on C-2U

    Energy Technology Data Exchange (ETDEWEB)

    Bolte, N. G., E-mail: nbolte@TriAlphaEnergy.com; Gupta, D.; Onofri, M.; Dettrick, S.; Granstedt, E. M.; Petrov, P. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States); Stagner, L. [University of California, Irvine, Irvine, California 92697 (United States)

    2016-11-15

    The first measurements of fast-ion D-alpha (FIDA) radiation have been acquired on C-2U, Tri Alpha Energy’s advanced, beam-driven field-reversed configuration (FRC). These measurements are also forward modeled by FIDASIM. This is the first measurement and simulation of FIDA carried out on an FRC topology. FIDA measurements are made of Doppler-shifted Balmer-alpha light from neutralized fast ions using a bandpass filter and photomultiplier tube. One adjustable line-of-sight measured signals at eight locations and eight times during the FRC lifetime over 26 discharges. Filtered signals include only the highest energy ions (>6 keV) and share some salient features with the FIDASIM result. Highly Doppler-shifted beam radiation is also measured with a high-speed camera and is spatially well-correlated with FIDASIM.

  3. First fast-ion D-alpha (FIDA) measurements and simulations on C-2U

    Science.gov (United States)

    Bolte, N. G.; Gupta, D.; Stagner, L.; Onofri, M.; Dettrick, S.; Granstedt, E. M.; Petrov, P.

    2016-11-01

    The first measurements of fast-ion D-alpha (FIDA) radiation have been acquired on C-2U, Tri Alpha Energy's advanced, beam-driven field-reversed configuration (FRC). These measurements are also forward modeled by FIDASIM. This is the first measurement and simulation of FIDA carried out on an FRC topology. FIDA measurements are made of Doppler-shifted Balmer-alpha light from neutralized fast ions using a bandpass filter and photomultiplier tube. One adjustable line-of-sight measured signals at eight locations and eight times during the FRC lifetime over 26 discharges. Filtered signals include only the highest energy ions (>6 keV) and share some salient features with the FIDASIM result. Highly Doppler-shifted beam radiation is also measured with a high-speed camera and is spatially well-correlated with FIDASIM.

  4. Velocity-space tomography of the fast-ion distribution function

    DEFF Research Database (Denmark)

    Jacobsen, Asger Schou; Salewski, Mirko; Geiger, Benedikt;

    2013-01-01

    Fast ions play an important role in heating the plasma in a magnetic confinement fusion device. Fast-ion Dα(FIDA) spectroscopy diagnoses fast ions in small measurement volumes. Spectra measured by a FIDA diagnostic can be related to the 2D fast-ion velocity distribution function. A single FIDA vi...

  5. Fast-ion Dα spectrum diagnostic in the EAST

    Science.gov (United States)

    Hou, Y. M.; Wu, C. R.; Huang, J.; Heidbrink, W. W.; von Hellermann, M. G.; Xu, Z.; Jin, Z.; Chang, J. F.; Zhu, Y. B.; Gao, W.; Chen, Y. J.; Lyu, B.; Hu, R. J.; Zhang, P. F.; Zhang, L.; Gao, W.; Wu, Z. W.; Yu, Y.; Ye, M. Y.

    2016-11-01

    In toroidal magnetic fusion devices, fast-ion D-alpha diagnostic (FIDA) is a powerful method to study the fast-ion feature. The fast-ion characteristics can be inferred from the Doppler shifted spectrum of Dα light according to charge exchange recombination process between fast ions and probe beam. Since conceptual design presented in the last HTPD conference, significant progress has been made to apply FIDA systems on the Experimental Advanced Superconducting Tokamak (EAST). Both co-current and counter-current neutral beam injectors are available, and each can deliver 2-4 MW beam power with 50-80 keV beam energy. Presently, two sets of high throughput spectrometer systems have been installed on EAST, allowing to capture passing and trapped fast-ion characteristics simultaneously, using Kaiser HoloSpec transmission grating spectrometer and Bunkoukeiki FLP-200 volume phase holographic spectrometer coupled with Princeton Instruments ProEM 1024B eXcelon and Andor DU-888 iXon3 1024 CCD camera, respectively. This paper will present the details of the hardware descriptions and experimental spectrum.

  6. Ion beam requirements for fast ignition of inertial fusion targets

    CERN Document Server

    Honrubia, J J

    2015-01-01

    Ion beam requirements for fast ignition are investigated by numerical simulation taking into account new effects such as ion beam divergence not included before. We assume that ions are generated by the TNSA scheme in a curved foil placed inside a re-entrant cone and focused on the cone apex or beyond. From the focusing point to the compressed core ions propagate with a given divergence angle. Ignition energies are obtained for two compressed fuel configurations heated by proton and carbon ion beams. The dependence of the ignition energies on the beam divergence angle and on the position of the ion beam focusing point have been analysed. Comparison between TNSA and quasi-monoenergetic ions is also shown.

  7. Fast ion behavior during neutral beam injection in ATF

    Energy Technology Data Exchange (ETDEWEB)

    Wade, M.R.; Thomas, C.E.; Colchin, R.J.; Rome, J.A.; England, A.C.; Fowler, R.H. [Oak Ridge National Lab., TN (United States); Aceto, S.C. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1993-09-01

    In stellarators, single-particle confinement properties can be more complex than in their tokamak counterparts. Fast-ion behavior in tokamaks has been well characterized through an abundance of measurements on various devices and in general has been shown to be consistent with classical slowing-down theory, although anomalous ion behavior has been observed during intense beam injection in ISX-B, during fishbone instabilities in PDX, and in experiments on TFR. In contrast, fast ion behavior in stellarators is not as wel established experimentally with the primary experiments to date focusing o near-perpendicular or perpendicular neutral beam injection (NBI) on the Wendelstein 7-A stellarator (91 and Heliotron-E. This paper addresses fast-ion confinement properties in a large-aspect-ratio, moderate-shear stellarator, the Advanced Toroidal Facility, during tangential NBI. The primary data used in this study are the experimentally measured energy spectra of charge-exchange neutrals escaping from the plasma, using a two-dimensional scanning neutral particle analyzer. This diagnostic method is well established, having been used on several devices since the early 1970`s. Various aspects of fast-ion behavior are investigated by comparing these data with computed theoretical spectra based on energeticion distributions derived from the fastion Fokker-Planck equation. Ion orbits are studied by computer orbit following, by the computation of J* surfaces, and by Monte Carlo calculations.

  8. Developmental Trajectories of Boys' Driven Exercise and Fasting During the Middle School Years.

    Science.gov (United States)

    Davis, Heather A; Guller, Leila; Smith, Gregory T

    2016-10-01

    Boys appear to engage in eating disorder behavior, particularly nonpurging compensatory behaviors such as driven exercise and fasting, at higher rates than previously thought. Little is known about the development of these behaviors in adolescent boys. In a sample of 631 non-binge eating and non-purging boys studied once in 5th grade and 6 times over the 3 years of middle school (grades 6 through 8), we found that (a) for some youth, driven exercise and fasting were present from grade 6; (b) different boys progressed along different trajectories of engagement in driven exercise and fasting, with some boys engaging in no driven exercise or fasting (65.8 % and 83.5 %, respectively), some boys engaging in driven exercise and fasting throughout middle school (25.2 % and 16.5 %, respectively), and other boys discontinuing engagement in driven exercise (9 %); (c) 5th grade depression, eating expectancies, and thinness expectancies predicted subsequent trajectory group membership; and (d) boys engaging in driven exercise and fasting in 8th grade remained distressed. Boys' engagement in driven exercise and fasting behavior merits the attention of researchers and clinicians.

  9. Performance characterization of rf-driven multicusp ion sources

    Science.gov (United States)

    Perkins, L. T.; De Vries, G. J.; Herz, P. R.; Kunkel, W. B.; Leung, K. N.; Pickard, D. S.; Wengrow, A.; Williams, M. D.

    1996-03-01

    Radio-frequency (rf)-driven multicusp ion sources have been developed extensively at Lawrence Berkeley National Laboratory (LBNL) for many applications, each requiring specific source designs. These uses have ranged from large ion sources for neutral-beam injectors—several tens of centimeters in size—to small sources for oil-well logging neutron tubes—a few centimeters in diameter. The advantages associated with internal antenna, rf-driven ion sources include reliability, long component life, ease of operation, and the ability to generate plasmas free of the impurities commonly found in hot-filament discharge sources. We have investigated and characterized the performance of rf-driven sources with respect to the rf operating frequency and ion source size for hydrogen ion species and current density. Furthermore, we have included in this study the aspects of proper coupling of the rf generator to the antenna through an impedance matching network. Finally, critical issues pertaining to general rf operation including beam extraction, rf shielding, and cooling of transformer cores are discussed.

  10. Performance characterization of rf-driven multicusp ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, L.T.; De Vries, G.J.; Herz, P.R.; Kunkel, W.B.; Leung, K.N.; Pickard, D.S.; Wengrow, A.; Williams, M.D. [Lawrence Berkeley National Laboratory, University of California at Berkeley, Berkeley, California 94720 (United States)

    1996-03-01

    Radio-frequency (rf)-driven multicusp ion sources have been developed extensively at Lawrence Berkeley National Laboratory (LBNL) for many applications, each requiring specific source designs. These uses have ranged from large ion sources for neutral-beam injectors{emdash}several tens of centimeters in size{emdash}to small sources for oil-well logging neutron tubes{emdash}a few centimeters in diameter. The advantages associated with internal antenna, rf-driven ion sources include reliability, long component life, ease of operation, and the ability to generate plasmas free of the impurities commonly found in hot-filament discharge sources. We have investigated and characterized the performance of rf-driven sources with respect to the rf operating frequency and ion source size for hydrogen ion species and current density. Furthermore, we have included in this study the aspects of proper coupling of the rf generator to the antenna through an impedance matching network. Finally, critical issues pertaining to general rf operation including beam extraction, rf shielding, and cooling of transformer cores are discussed.

  11. Drift and ion acoustic wave driven vortices with superthermal electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ali Shan, S. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); National Centre For Physics (NCP), Shahdra Valley Road, QAU Campus, 44000 Islamabad (Pakistan); Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad (Pakistan); Haque, Q. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); National Centre For Physics (NCP), Shahdra Valley Road, QAU Campus, 44000 Islamabad (Pakistan)

    2012-08-15

    Linear and nonlinear analysis of coupled drift and acoustic mode is presented in an inhomogeneous electron-ion plasma with {kappa}-distributed electrons. A linear dispersion relation is found which shows that the phase speed of both the drift wave and the ion acoustic wave decreases in the presence of superthermal electrons. Several limiting cases are also discussed. In the nonlinear regime, stationary solutions in the form of dipolar and monopolar vortices are obtained. It is shown that the condition for the boundedness of the solution implies that the speed of drift wave driven vortices reduces with increase in superthermality effect. Ignoring density inhomogeniety, it is investigated that the lower and upper limits on the speed of the ion acoustic driven vortices spread with the inclusion of high energy electrons. The importance of results with reference to space plasmas is also pointed out.

  12. Active and fast particle driven Alfvén eigenmodes in Alcator C-Moda)

    Science.gov (United States)

    Snipes, J. A.; Basse, N.; Boswell, C.; Edlund, E.; Fasoli, A.; Gorelenkov, N. N.; Granetz, R. S.; Lin, L.; Lin, Y.; Parker, R.; Porkolab, M.; Sears, J.; Sharapov, S.; Tang, V.; Wukitch, S.

    2005-05-01

    Alfvén eigenmodes (AEs) are studied to assess their stability in high density reactor relevant regimes where Ti≈Te and as a diagnostic tool. Stable AEs are excited with active magnetohydrodynamics antennas in the range of the expected AE frequency. Toroidal Alfvén eigenmode (TAE) damping rates between 0.5%<γ/ω<4.5% have been observed in diverted and limited Ohmic plasmas. Unstable AEs are excited with a fast ion tail driven by H minority ion cyclotron radio frequency (ICRF) heating with electron densities in the range of n¯e=0.5-2×1020m-3. Energetic particle modes or TAEs have been observed to decrease in frequency and mode number with time up to a large sawtooth collapse, indicating the role fast particles play in stabilizing sawteeth. In the current rise phase, unstable modes with frequencies that increase rapidly with time are observed with magnetic pick-up coils at the wall and phase contrast imaging density fluctuation measurements in the core. Modeling of these modes constrains the calculated safety factor profile to be very flat or with slightly reversed shear. AEs are found to be more stable for an inboard than for central or outboard ICRF resonances in qualitative agreement with modeling.

  13. Electrically Driven Ion Separations in Permeable Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Bruening, Merlin [Michigan State Univ., East Lansing, MI (United States)

    2017-04-21

    Membranes are attractive for a wide range of separations due to their low energy costs and continuous operation. To achieve practical fluxes, most membranes consist of a thin, selective skin on a highly permeable substrate that provides mechanical strength. Thus, this project focused on creating new methods for forming highly selective ultrathin skins as well as modeling transport through these coatings to better understand their unprecedented selectivities. The research explored both gas and ion separations, and the latter included transport due to concentration, pressure and electrical potential gradients. This report describes a series of highlights of the research and then provides a complete list of publications supported by the grant. These publications have been cited more than 4000 times. Perhaps the most stunning finding is the recent discovery of monovalent/divalent cation and anion selectivities around 1000 when modifying cation- and anion-exchange membranes with polyelectrolyte multilayers (PEMs). This discovery builds on many years of exciting research. (Citation numbers refer to the journal articles in the bibliography.)

  14. Three-dimensional fast magnetic reconnection driven by relativistic ultraintense femtosecond lasers.

    Science.gov (United States)

    Ping, Y L; Zhong, J Y; Sheng, Z M; Wang, X G; Liu, B; Li, Y T; Yan, X Q; He, X T; Zhang, J; Zhao, G

    2014-03-01

    Three-dimensional fast magnetic reconnection driven by two ultraintense femtosecond laser pulses is investigated by relativistic particle-in-cell simulation, where the two paralleled incident laser beams are shot into a near-critical plasma layer to form a magnetic reconnection configuration in self-generated magnetic fields. A reconnection X point and out-of-plane quadrupole field structures associated with magnetic reconnection are formed. The reconnection rate is found to be faster than that found in previous two-dimensional Hall magnetohydrodynamic simulations and electrostatic turbulence contribution to the reconnection electric field plays an essential role. Both in-plane and out-of-plane electron and ion accelerations up to a few MeV due to the magnetic reconnection process are also obtained.

  15. Polarization Bremsstrahlung in collissions of fast ions with multiatomic targets

    CERN Document Server

    Amusia, M Ya

    2013-01-01

    We consider the processes of polarization bremsstrahlung in collisions of fast ions with linear chains consisting of isolated atoms. We obtained intensities and angular distributions of radiation spectra for arbitrary number of atoms in the chain. It appeared that interference in the photon radiation amplitudes lead to prominent variation of spectral angular distributions of polarization bremsstrahlung as compared to these distribuitions in collisions with an isolated atom. The mean loss of energy due to radiation or the so-called rediative friction is estimated. The results obtained permit standard generalization to the case of polarization bremsstrahlung in fast ion chanelling above surfaces an and in solid body.

  16. Review of laser-driven ion sources and their applications.

    Science.gov (United States)

    Daido, Hiroyuki; Nishiuchi, Mamiko; Pirozhkov, Alexander S

    2012-05-01

    For many years, laser-driven ion acceleration, mainly proton acceleration, has been proposed and a number of proof-of-principle experiments have been carried out with lasers whose pulse duration was in the nanosecond range. In the 1990s, ion acceleration in a relativistic plasma was demonstrated with ultra-short pulse lasers based on the chirped pulse amplification technique which can provide not only picosecond or femtosecond laser pulse duration, but simultaneously ultra-high peak power of terawatt to petawatt levels. Starting from the year 2000, several groups demonstrated low transverse emittance, tens of MeV proton beams with a conversion efficiency of up to several percent. The laser-accelerated particle beams have a duration of the order of a few picoseconds at the source, an ultra-high peak current and a broad energy spectrum, which make them suitable for many, including several unique, applications. This paper reviews, firstly, the historical background including the early laser-matter interaction studies on energetic ion acceleration relevant to inertial confinement fusion. Secondly, we describe several implemented and proposed mechanisms of proton and/or ion acceleration driven by ultra-short high-intensity lasers. We pay special attention to relatively simple models of several acceleration regimes. The models connect the laser, plasma and proton/ion beam parameters, predicting important features, such as energy spectral shape, optimum conditions and scalings under these conditions for maximum ion energy, conversion efficiency, etc. The models also suggest possible ways to manipulate the proton/ion beams by tailoring the target and irradiation conditions. Thirdly, we review experimental results on proton/ion acceleration, starting with the description of driving lasers. We list experimental results and show general trends of parameter dependences and compare them with the theoretical predictions and simulations. The fourth topic includes a review of

  17. Fast and efficient transport of large ion clouds

    CERN Document Server

    Kamsap, Marius Romuald; Champenois, Caroline; Guyomarc'H, Didier; Houssin, Marie; Knoop, Martina

    2015-01-01

    The manipulation of trapped charged particles by electric fields is an accurate, robust and reliable technique for many applications or experiments in high-precision spectroscopy. The transfer of the ion sample between multiple traps allows the use of a tailored environment in quantum information, cold chemistry, or frequency metrology experiments. In this article, we experimentally study the transport of ion clouds of up to 50 000 ions. The design of the trap makes ions very sensitive to any mismatch between the assumed electric potential and the actual local one. Nevertheless, we show that being fast (100 $\\mu$s to transfer over more than 20 mm) increases the transport efficiency to values higher than 90 %, even with a large number of ions. For clouds of less than 2000 ions, a 100 % transfer efficiency is observed.

  18. Distortion of He emission lines after fast-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Arcuni, P.W.

    1985-01-01

    After excitation by fast ions (velocity = 2 to 5 au) the emission line profiles of doubly-excited helium atoms are observed to differ significantly from the normal shape of Beutler-Fano resonances. This difference is attributed to the Coulomb interaction between the emitted electron and the ion used to excite the atom. We explain the effect quantitatively with a simple classical model combined with a post-collision-interaction theory. 4 refs., 4 figs.

  19. Fast cooling of trapped ions using the dynamical Stark shift

    Energy Technology Data Exchange (ETDEWEB)

    Retzker, A [Institute for Mathematical Sciences, Imperial College London, SW7 2PE (United Kingdom); Plenio, M B [Institute for Mathematical Sciences, Imperial College London, SW7 2PE (United Kingdom)

    2007-08-15

    A laser cooling scheme for trapped ions is presented which is based on the fast dynamical Stark shift gate, described in (Jonathan et al 2000 Phys. Rev. A 62 042307). Since this cooling method does not contain an off resonant carrier transition, low final temperatures are achieved even in a traveling wave light field. The proposed method may operate in either pulsed or continuous mode and is also suitable for ion traps using microwave addressing in strong magnetic field gradients.

  20. Small radio frequency driven multicusp ion source for positive hydrogen ion beam production

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, L.T.; Herz, P.R.; Leung, K.N.; Pickard, D.S. (Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States))

    1994-04-01

    A compact, 2.5 cm diam rf-driven multicusp ion source has been developed and tested for H[sup +] ion production in pulse mode operation. The source is optimized for atomic hydrogen ion species and extractable current. It is found that hydrogen ion beam current densities in excess of 650 mA/cm[sup 2] can be achieved with H[sup +] species above 80%. The geometry and position of the porcelain-coated copper antenna were found to be of great significance in relation to the efficiency of the ion source.

  1. Fast ion-atom and ion-molecule collisions

    CERN Document Server

    2013-01-01

    The principal goal of this book is to provide state-of-the art coverage of the non-relativistic three- and four-body theories at intermediate and high energy ion-atom and ion-molecule collisions. The focus is on the most frequently studied processes: electron capture, ionization, transfer excitation and transfer ionization. The content is suitable both for graduate students and experienced researchers. For these collisions, the literature has seen enormous renewal of activity in the development and applications of quantum-mechanical theories. This subject is of relevance in several branches of science and technology, like accelerator-based physics, the search for new sources of energy and high temperature fusion of light ions. Other important applications are in life sciences via medicine, where high-energy ion beams are used in radiotherapy for which a number of storage ring accelerators are in full operation, under construction or planned to be built worldwide. Therefore, it is necessary to review this fiel...

  2. Potential of ion cyclotron resonance frequency current drive via fast waves in DEMO

    Science.gov (United States)

    Kazakov, Ye O.; Van Eester, D.; Wauters, T.; Lerche, E.; Ongena, J.

    2015-02-01

    For the continuous operation of future tokamak-reactors like DEMO, non-inductively driven toroidal plasma current is needed. Bootstrap current, due to the pressure gradient, and current driven by auxiliary heating systems are currently considered as the two main options. This paper addresses the current drive (CD) potential of the ion cyclotron resonance frequency (ICRF) heating system in DEMO-like plasmas. Fast wave CD scenarios are evaluated for both the standard midplane launch and an alternative case of exciting the waves from the top of the machine. Optimal ICRF frequencies and parallel wave numbers are identified to maximize the CD efficiency. Limitations of the high frequency ICRF CD operation are discussed. A simplified analytical method to estimate the fast wave CD efficiency is presented, complemented with the discussion of its dependencies on plasma parameters. The calculated CD efficiency for the ICRF system is shown to be similar to those for the negative neutral beam injection and electron cyclotron resonance heating.

  3. Stochastic Acceleration of Ions Driven by Pc1 Wave Packets

    Science.gov (United States)

    Khazanov, G. V.; Sibeck, D. G.; Tel'nikhin, A. A.; Kronberg, T. K.

    2015-01-01

    The stochastic motion of protons and He(sup +) ions driven by Pc1 wave packets is studied in the context of resonant particle heating. Resonant ion cyclotron heating typically occurs when wave powers exceed 10(exp -4) nT sq/Hz. Gyroresonance breaks the first adiabatic invariant and energizes keV ions. Cherenkov resonances with the electrostatic component of wave packets can also accelerate ions. The main effect of this interaction is to accelerate thermal protons to the local Alfven speed. The dependencies of observable quantities on the wave power and plasma parameters are determined, and estimates for the heating extent and rate of particle heating in these wave-particle interactions are shown to be in reasonable agreement with known empirical data.

  4. Polarization Studies in Fast-Ion Beam Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2001-12-20

    In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams.

  5. Fast Preparation of W States for Hot Trapped Ions

    Institute of Scientific and Technical Information of China (English)

    ZHENGShi-Biao

    2005-01-01

    A scheme is presented for generating W states for three or four trapped ions in thermal motion. The scheme works in the regime, where the Rabi frequency of the laser field is on the order of the trap frequency, resulting a fast entanglement speed, which is of importance in view of decoherence.

  6. Fast Preparation of W States for Hot Trapped Ions

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2005-01-01

    A scheme is presented for generating W states for three o()four trapped ions in thermal motion. The scheme works in the regime, where the Rabi frequency of the laser field is on the order of the trap frequency, resulting a fast entanglement speed, which is of importance in view of decoherence.

  7. Fast ion swapping for quantum-information processing

    Science.gov (United States)

    Kaufmann, H.; Ruster, T.; Schmiegelow, C. T.; Luda, M. A.; Kaushal, V.; Schulz, J.; von Lindenfels, D.; Schmidt-Kaler, F.; Poschinger, U. G.

    2017-05-01

    We demonstrate a swap gate between laser-cooled ions in a segmented microtrap via fast physical swapping of the ion positions. This operation is used in conjunction with qubit initialization, manipulation, and readout and with other types of shuttling operations such as linear transport and crystal separation and merging. Combining these operations, we perform quantum process tomography of the swap gate, obtaining a mean process fidelity of 99.5(5)%. The swap operation is demonstrated with motional excitations below 0.05(1) quantum for all six collective modes of a two-ion crystal for a process duration of 42 μ s . Extending these techniques to three ions, we reverse the order of a three-ion crystal and reconstruct the truth table for this operation, resulting in a mean process fidelity of 99.96(13)% in the logical basis.

  8. A compact filament-driven multicusp ion source

    Science.gov (United States)

    Lee, Y.; Gough, R. A.; Kunkel, W. B.; Leung, K. N.; Perkins, L. T.; Pickard, D. S.; Sun, L.; Vujic, J.; Williams, M. D.; Wutte, D.

    1996-12-01

    A compact filament-driven multicusp ion source has been studied using both hydrogen and helium. Three aspects of the source have been investigated: hydrogen ion species, axial energy spread and extractable current. An atomic ion fraction (H +) of approximately 30% could be obtained with a discharge power of 80 V and 3 A. A magnetic analyzer was used to determine the axial energy spread of the extracted (i.e. accelerated) ion beam species, and an electrostatic energy analyzer was used to determine the energy spread of the ions at the source exit. The energy spread of the extracted beam for the individual species of positive hydrogen ions (H +, H 2+, H 3+) and that for the negative hydrogen ions (H -) was measured as well. Energy spreads as low as 2.3 eV were obtained for H +, 2 eV for H 2+, 1.7 eV for H 3+, and 1 eV for H -. The axial energy spread in the source exit without extraction for hydrogen and helium was measured to be approximately 1 eV for both cases. The source can generate a hydrogen beam current density of approximately 12 mA/cm 2.

  9. Fast thermometry for trapped ions using dark resonances

    CERN Document Server

    Roßnagel, Johannes; Schmidt-Kaler, Ferdinand; Singer, Kilian

    2014-01-01

    We experimentally demonstrate a method to determine the temperature of trapped ions which is suitable for monitoring fast thermalization processes. We show that observing and analyzing the lineshape of dark resonances in the fluorescence spectrum provides a temperature measurement which accurate over a large dynamic range, applied to single ions and small ion crystals. Laser induced fluorescence is detected over a time of only $20\\,\\mu$s allowing for rapid determination of the ion temperature. In the measurement range of $10^{-1}-10^{+2}\\,$mK we reach better than $15\\,\\%$ accuracy. Tuning the cooling laser to selected resonance features allows for controlling the ion temperatures between $0.7\\,$mK and more than $10\\,$mK. Experimental work is supported by a solution of the 8-level optical Bloch equations when including the ions classical motion. This technique paves the way for many experiments comprising heat transport in ion strings, heat engines, non-equilibrium thermodynamics or thermometry of large ion cr...

  10. 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

  11. Coincidence ion imaging with a fast frame camera

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Suk Kyoung; Cudry, Fadia; Lin, Yun Fei; Lingenfelter, Steven; Winney, Alexander H.; Fan, Lin; Li, Wen, E-mail: wli@chem.wayne.edu [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States)

    2014-12-15

    A new time- and position-sensitive particle detection system based on a fast frame CMOS (complementary metal-oxide semiconductors) camera is developed for coincidence ion imaging. The system is composed of four major components: a conventional microchannel plate/phosphor screen ion imager, a fast frame CMOS camera, a single anode photomultiplier tube (PMT), and a high-speed digitizer. The system collects the positional information of ions from a fast frame camera through real-time centroiding while the arrival times are obtained from the timing signal of a PMT processed by a high-speed digitizer. Multi-hit capability is achieved by correlating the intensity of ion spots on each camera frame with the peak heights on the corresponding time-of-flight spectrum of a PMT. Efficient computer algorithms are developed to process camera frames and digitizer traces in real-time at 1 kHz laser repetition rate. We demonstrate the capability of this system by detecting a momentum-matched co-fragments pair (methyl and iodine cations) produced from strong field dissociative double ionization of methyl iodide.

  12. Diagnostics for ion beam driven high energy density physics experiments.

    Science.gov (United States)

    Bieniosek, F M; Henestroza, E; Lidia, S; Ni, P A

    2010-10-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K(+) beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  13. Diagnostics for ion beam driven high energy density physics experimentsa)

    Science.gov (United States)

    Bieniosek, F. M.; Henestroza, E.; Lidia, S.; Ni, P. A.

    2010-10-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K+ beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  14. Shutterless ion mobility spectrometer with fast pulsed electron source

    Science.gov (United States)

    Bunert, E.; Heptner, A.; Reinecke, T.; Kirk, A. T.; Zimmermann, S.

    2017-02-01

    Ion mobility spectrometers (IMS) are devices for fast and very sensitive trace gas analysis. The measuring principle is based on an initial ionization process of the target analyte. Most IMS employ radioactive electron sources, such as 63Ni or 3H. These radioactive materials have the disadvantage of legal restrictions and the electron emission has a predetermined intensity and cannot be controlled or disabled. In this work, we replaced the 3H source of our IMS with 100 mm drift tube length with our nonradioactive electron source, which generates comparable spectra to the 3H source. An advantage of our emission current controlled nonradioactive electron source is that it can operate in a fast pulsed mode with high electron intensities. By optimizing the geometric parameters and developing fast control electronics, we can achieve very short electron emission pulses for ionization with high intensities and an adjustable pulse width of down to a few nanoseconds. This results in small ion packets at simultaneously high ion densities, which are subsequently separated in the drift tube. Normally, the required small ion packet is generated by a complex ion shutter mechanism. By omitting the additional reaction chamber, the ion packet can be generated directly at the beginning of the drift tube by our pulsed nonradioactive electron source with only slight reduction in resolving power. Thus, the complex and costly shutter mechanism and its electronics can also be omitted, which leads to a simple low-cost IMS-system with a pulsed nonradioactive electron source and a resolving power of 90.

  15. Conceptual design of the ITER fast-ion loss detector

    Science.gov (United States)

    Garcia-Munoz, M.; Kocan, M.; Ayllon-Guerola, J.; Bertalot, L.; Bonnet, Y.; Casal, N.; Galdon, J.; Garcia Lopez, J.; Giacomin, T.; Gonzalez-Martin, J.; Gunn, J. P.; Jimenez-Ramos, M. C.; Kiptily, V.; Pinches, S. D.; Rodriguez-Ramos, M.; Reichle, R.; Rivero-Rodriguez, J. F.; Sanchis-Sanchez, L.; Snicker, A.; Vayakis, G.; Veshchev, E.; Vorpahl, Ch.; Walsh, M.; Walton, R.

    2016-11-01

    A conceptual design of a reciprocating fast-ion loss detector for ITER has been developed and is presented here. Fast-ion orbit simulations in a 3D magnetic equilibrium and up-to-date first wall have been carried out to revise the measurement requirements for the lost alpha monitor in ITER. In agreement with recent observations, the simulations presented here suggest that a pitch-angle resolution of ˜5° might be necessary to identify the loss mechanisms. Synthetic measurements including realistic lost alpha-particle as well as neutron and gamma fluxes predict scintillator signal-to-noise levels measurable with standard light acquisition systems with the detector aperture at ˜11 cm outside of the diagnostic first wall. At measurement position, heat load on detector head is comparable to that in present devices.

  16. Fast ion generation and bulk plasma heating with three-ion ICRF scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Kazakov, Ye. O., E-mail: yevgen.kazakov@rma.ac.be; Van Eester, D.; Ongena, J.; Lerche, E.; Messiaen, A. [Laboratory for Plasma Physics, LPP-ERM/KMS, EUROfusion Consortium Member, Brussels (Belgium); Dumont, R. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2015-12-10

    Launching electromagnetic waves in the ion cyclotron range of frequencies (ICRF) is an efficient method of plasma heating, actively employed in most of fusion machines. ICRF has a number of important supplementary applications, including the generation of high-energy ions. In this paper, we discuss a new set of three-ion ICRF scenarios and the prospect of their use as a dedicated tool for fast ion generation in tokamaks and stellarators. A distinct feature of these scenarios is a strong absorption efficiency possible at very low concentrations of resonant minority ions (∼ 1% or even below). Such concentration levels are typical for impurities contaminating fusion plasmas. An alternative ICRF scenario for maximizing the efficiency of bulk D-T ion heating is suggested for JET and ITER tokamaks, which is based on three-ion ICRF heating of intrinsic Beryllium impurities.

  17. Fast ion generation and bulk plasma heating with three-ion ICRF scenarios

    Science.gov (United States)

    Kazakov, Ye. O.; Van Eester, D.; Dumont, R.; Ongena, J.; Lerche, E.; Messiaen, A.

    2015-12-01

    Launching electromagnetic waves in the ion cyclotron range of frequencies (ICRF) is an efficient method of plasma heating, actively employed in most of fusion machines. ICRF has a number of important supplementary applications, including the generation of high-energy ions. In this paper, we discuss a new set of three-ion ICRF scenarios and the prospect of their use as a dedicated tool for fast ion generation in tokamaks and stellarators. A distinct feature of these scenarios is a strong absorption efficiency possible at very low concentrations of resonant minority ions (˜ 1% or even below). Such concentration levels are typical for impurities contaminating fusion plasmas. An alternative ICRF scenario for maximizing the efficiency of bulk D-T ion heating is suggested for JET and ITER tokamaks, which is based on three-ion ICRF heating of intrinsic Beryllium impurities.

  18. FIFPC, a fast ion Fokker--Planck code

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, R.H.; Callen, J.D.; Rome, J.A.; Smith, J.

    1976-07-01

    A computer code is described which solves the Fokker--Planck equation for the velocity space distribution of fast ions injected into a tokamak plasma. The numerical techniques are described and use of the code is outlined. The program is written in FORTRAN IV and is modularized in order to provide greater flexibility to the user. A program listing is provided and the results of sample cases are presented.

  19. Momentum imaging of photofragments and photoelectrons using fast ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Domesle, Christian

    2012-07-04

    Momentum imaging of photofragments and photoelectrons using fast ion beams - Within the framework of this thesis a method for break-up channel specific detection of the photoelectrons from photon-induced dissociation processes of fast moving molecular ion has been established. For this purpose, a novel saddlepoint electron spectrometer was commissioned while investigating the photodetachment dynamics on a fast moving beam of oxygen anions. For a complete detection of all outgoing reaction products emerging from the photolysis of small water clusters (H{sub 2}O){sub n}H{sup +}(n≤3) in the wavelength range of 13.5-40 nm a new fragment analyzing system has been developed and in combination with the novel saddle-point spectrometer applied, to investigate the dissociative photoionization of the hydronium (H{sub 3}O{sup +}) and the Zundel ion (H{sub 5}O{sub 2}{sup +}). In case of the hydronium ion, a binary H{sub 2}O{sup +}+H{sup +} and two three-body channels OH{sup +}+2H{sup +}, OH{sup +}+H{sup +}+H have been identified to be initiated by outer valence vacancies, where the binary channel is mainly triggered by the ionization of the 3a{sub 1} orbital and the three-body channels follow ionization from the 1e orbital. The photolysis of H{sub 5}O{sub 2}{sup +} is found to proceed via five prominent pathways, where for a large number of processes the hydronium ion is split off as a stable structural unit. Also here, the investigation of the photoelectron spectra revealed the prominent dissociation pathways to be initiated by outer valence vacancies.

  20. Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade

    DEFF Research Database (Denmark)

    Rasmussen, Jesper; Nielsen, Stefan Kragh; Pedersen, Morten Stejner;

    2016-01-01

    Sawtooth instabilities can modify heating and current-drive profiles and potentially increase fast-ion losses. Understanding how sawteeth redistribute fast ions as a function of sawtooth parameters and of fast-ion energy and pitch is hence a subject of particular interest for future fusion device...

  1. Dynamics of fast ions during sawtooth oscillations in the TEXTOR tokamak measured by collective Thomson scattering

    NARCIS (Netherlands)

    Nielsen, S.K.; Salewski, M.; Bindslev, H.; Burger, A.; Furtula, V.; Kantor, M.; Korsholm, S. B.; Koslowski, H. R.; Kramer-Flecken, A.; Leipold, F.; Meo, F.; Michelsen, P. K.; Moseev, D.; Oosterbeek, J. W.; Stejner, M.; Westerhof, E.

    2011-01-01

    Experimental investigations of sawteeth interaction with fast ions measured by collective Thomson scattering on TEXTOR are presented. Time-resolved measurements of localized 1D fast-ion distribution functions allow us to study fast-ion dynamics during several sawtooth cycles. Sawtooth oscillations

  2. Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade

    DEFF Research Database (Denmark)

    Rasmussen, Jesper; Nielsen, Stefan Kragh; Pedersen, Morten Stejner

    2016-01-01

    Sawtooth instabilities can modify heating and current-drive profiles and potentially increase fast-ion losses. Understanding how sawteeth redistribute fast ions as a function of sawtooth parameters and of fast-ion energy and pitch is hence a subject of particular interest for future fusion devices...

  3. Dynamics of fast ions during sawtooth oscillations in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Salewski, Mirko; Bindslev, Henrik

    2011-01-01

    Experimental investigations of sawteeth interaction with fast ions measured by collective Thomson scattering on TEXTOR are presented. Time-resolved measurements of localized 1D fast-ion distribution functions allow us to study fast-ion dynamics during several sawtooth cycles. Sawtooth oscillation...

  4. Longitudinal dynamics of laser-cooled fast ion beams

    DEFF Research Database (Denmark)

    Weidemüller, M.; Eike, B.; Eisenbarth, U.

    1999-01-01

    We present recent results of our experiments on laser cooling of fast stored ion beams at the Heidelberg Test Storage Ring. The longitudinal motion of the ions is directly cooled by the light pressure force, whereas efficient transverse cooling is obtained indirectly by longitudinal......-transverse coupling mechanisms. Laser cooling in novel bunch forms consisting of square-well buckets leads to longitudinally space-charge dominated beams. The observed longitudinal ion density distributions can be well described by a self-consistent mean-field model based on a thermodynamic Debye-Huckel approach....... When applying laser cooling in square-well buckets over long time intervals, hard Coulomb collisions suddenly disappear and the longitudinal temperature drops by about a factor of three. The observed longitudinal behaviour of the beam shows strong resemblance with the transition to an Coulomb...

  5. Ion energy spread and current measurements of the rf-driven multicusp ion source

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.; Gough, R.A.; Kunkel, W.B.; Leung, K.N.; Perkins, L.T.; Pickard, D.S.; Sun, L.; Vujic, J.; Williams, M.D.; Wutte, D. [Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)

    1997-03-01

    Axial energy spread and useful beam current of positive ion beams have been carried out using a radio frequency (rf)-driven multicusp ion source. Operating the source with a 13.56 MHz induction discharge, the axial energy spread is found to be approximately 3.2 eV. The extractable beam current of the rf-driven source is found to be comparable to that of filament-discharge sources. With a 0.6 mm diameter extraction aperture, a positive hydrogen ion beam current density of 80 mA/cm{sup 2} can be obtained at a rf input power of 2.5 kW. The expected source lifetime is much longer than that of filament discharges. {copyright} {ital 1997 American Institute of Physics.}

  6. Ion energy spread and current measurements of the rf-driven multicusp ion source

    Science.gov (United States)

    Lee, Y.; Gough, R. A.; Kunkel, W. B.; Leung, K. N.; Perkins, L. T.; Pickard, D. S.; Sun, L.; Vujic, J.; Williams, M. D.; Wutte, D.

    1997-03-01

    Axial energy spread and useful beam current of positive ion beams have been carried out using a radio frequency (rf)-driven multicusp ion source. Operating the source with a 13.56 MHz induction discharge, the axial energy spread is found to be approximately 3.2 eV. The extractable beam current of the rf-driven source is found to be comparable to that of filament-discharge sources. With a 0.6 mm diameter extraction aperture, a positive hydrogen ion beam current density of 80 mA/cm2 can be obtained at a rf input power of 2.5 kW. The expected source lifetime is much longer than that of filament discharges.

  7. Ion-beam-driven warm dense matter experiments

    Science.gov (United States)

    Bieniosek, F. M.; Barnard, J. J.; Friedman, A.; Henestroza, E.; Jung, J. Y.; Leitner, M. A.; Lidia, S.; Logan, B. G.; More, R. M.; Ni, P. A.; Roy, P. K.; Seidl, P. A.; Waldron, W. L.

    2010-08-01

    As a technique for heating matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition to a relatively large sample. The US heavy ion fusion science program has developed techniques for heating and diagnosing warm dense matter (WDM) targets. We have developed a WDM target chamber and a suite of target diagnostics including a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments heat targets by both the compressed and uncompressed parts of the NDCX-I beam, and explore measurement of temperature, droplet formation and other target parameters. Continued improvements in beam tuning, bunch compression, and other upgrades are expected to yield higher temperature and pressure in the WDM targets. Future experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  8. Strong ambipolar-driven ion upflow within the cleft ion fountain during low geomagnetic activity

    Science.gov (United States)

    Shen, Yangyang; Knudsen, David J.; Burchill, Johnathan K.; Howarth, Andrew; Yau, Andrew; Redmon, Robert J.; Miles, David M.; Varney, Roger H.; Nicolls, Michael J.

    2016-07-01

    We investigate low-energy (CIF) using conjunctions of the Enhanced Polar Outflow Probe (e-POP) satellite, the DMSP F16 satellite, the SuperDARN radar, and the Resolute Bay Incoherent Scatter Radar North (RISR-N). The SEI instrument on board e-POP enables us to derive ion upflow velocities from the 2-D images of ion distribution functions with a frame rate of 100 images per second, and with a velocity resolution of the order of 25 m/s. We identify three cleft ion fountain events with very intense (>1.6 km/s) ion upflow velocities near 1000 km altitude during quiet geomagnetic activity (Kp CIF does not rise by more than 0.3 eV relative to background values, which is consistent with RISR-N observations in the F region. The presence of soft electron precipitation seen by DMSP and lack of significant ion heating indicate that the ion upflows we observe near 1000 km altitude are primarily driven by ambipolar electric fields. DC field-aligned currents (FACs) and convection velocity gradients accompany these events. The strongest ion upflows are associated with downward current regions, which is consistent with some (although not all) previously published results. The moderate correlation coefficient (0.51) between upflow velocities and currents implies that FACs serve as indirect energy inputs to the ion upflow process.

  9. Fast Ion Effects on Fishbones and n=1 Kinks in JET Simulated by a Non-perturbative NOVA-KN Code

    Energy Technology Data Exchange (ETDEWEB)

    N.N. Gorelenkov; C.Z. Cheng; V.G. Kiptily; M.J. Mantsinen; S.E. Sharapov; the JET-EFDA Contributors

    2004-10-28

    New global non-perturbative hybrid code, NOVA-KN, and simulations of resonant type modes in JET [Joint European Torus] plasmas driven by energetic H-minority ions are presented. The NOVA-KN code employs the ideal-MHD description for the background plasma and treats non-perturbatively the fast particle kinetic response, which includes the fast ion finite orbit width (FOW) effect. In particular, the n = 1 fishbone mode, which is in precession drift resonance with fast ions, is studied. The NOVA-KN code is applied to model an n = 1 (f = 50-80kHz) MHD activity observed recently in JET low density plasma discharges with high fast ion (H-minority) energy content generated during the ion cyclotron resonance heating (ICRH). This n = 1 MHD activity is interpreted as the instability of the n = 1 precession drift frequency fishbone modes.

  10. 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.

  11. Measurement of a 2D fast-ion velocity distribution function by tomographic inversion of fast-ion D-alpha spectra

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Jacobsen, Asger Schou

    2014-01-01

    We present the first measurement of a local fast-ion 2D velocity distribution function f(v‖, v⊥). To this end, we heated a plasma in ASDEX Upgrade by neutral beam injection and measured spectra of fast-ion Dα (FIDA) light from the plasma centre in three views simultaneously. The measured spectra ...

  12. Progress on Bayesian Inference of the Fast Ion Distribution Function

    DEFF Research Database (Denmark)

    Stagner, L.; Heidbrink, W.W,; Chen, X.;

    2013-01-01

    The fast-ion distribution function (DF) has a complicated dependence on several phase-space variables. The standard analysis procedure in energetic particle research is to compute the DF theoretically, use that DF in forward modeling to predict diagnostic signals, then compare with measured data...... sensitivity of the measurements are incorporated into Bayesian likelihood probabilities. Prior probabilities describe physical constraints. This poster will show reconstructions of classically described, low-power, MHD-quiescent distribution functions from actual FIDA measurements. A description of the full...

  13. Warm Dense Matter Experiments Driven by Ion Beams

    Science.gov (United States)

    Bieniosek, F. M.; Henestroza, E.; Jung, J. Y.; Leitner, M. A.; Lidia, S.; Logan, B. G.; More, R. M.; Ni, P. A.; Roy, P. K.; Seidl, P. A.; Waldron, W. L.; Barnard, J. J.; Friedman, A.

    2009-11-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. We present results from warm dense matter (WDM) experiments at NDCX-I. The 0.3 MeV, 30-mA K^+ beam from the NDCX-I accelerator heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam to a spot size ˜ 1 mm, and compressed pulse length ˜ 2 ns. The uncompressed beam flux is >=500 kW/cm^2, and the compressed pulse flux is > 5 MW/cm^2. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. Future plans include construction of the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-4 MeV lithium ion beam. We have developed a target chamber and target diagnostics including a fast multi-channel optical pyrometer, optical streak camera, and high-speed gated cameras. We compare measurements of temperature, droplet formation and other target parameters with model predictions. Continued improvements in beam tuning, bunch compression, and other upgrades are expected to yield higher flux on target.

  14. Elastic wave from fast heavy ion irradiation on solids

    Science.gov (United States)

    Kambara, T.; Kageyama, K.; Kanai, Y.; Kojima, T. M.; Nanai, Y.; Yoneda, A.; Yamazaki, Y.

    2002-06-01

    To study the time-dependent mechanical effects of fast heavy ion irradiations, we have irradiated various solids by a short-bunch beam of 95 MeV/u Ar ions and observed elastic waves generated in the bulk. The irradiated targets were square-shaped plates of poly-crystals of metals (Al and Cu), invar alloy, ceramic (Al 2O 3), fused silica (SiO 2) and single crystals of KC1 and LiF with a thickness of 10 mm. The beam was incident perpendicular to the surface and all ions were stopped in the target. Two piezo-electric ultrasonic sensors were attached to the surface of the target and detected the elastic waves. The elastic waveforms as well as the time structure and intensity of the beam bunch were recorded for each shot of a beam bunch. The sensor placed opposite to the beam spot recorded a clear waveform of the longitudinal wave across the material, except for the invar and fused silica targets. From its propagation time along with the sound velocity and the thickness of the target, the depth of the wave source was estimated. The result was compared with ion ranges calculated for these materials by TRIM code.

  15. Development of an rf driven multicusp ion source for nuclear science experiments

    Science.gov (United States)

    Wutte, D.; Freedman, S.; Gough, R.; Lee, Y.; Leitner, M.; Leung, K. N.; Lyneis, C.; Pickard, D. S.; Williams, M. D.; Xie, Z. Q.

    1998-07-01

    A compact 13.56 MHz radio-frequency (rf) driven multicusp ion source is under development at Lawrence Berkeley National Laboratory (LBNL) for radioactive ion beam applications. In this paper we describe the ion source design and the general ion source performance using H 2, Ar, Xe gas and a 90% Ar/10% CO gas mixture for generating the discharge plasma. The following ion source characteristics have been analyzed: extractable ion current, ion species distributions, ionization efficiency for nobel gases, axial energy spread and ion beam emittance measurements. This ion source can generate ion current densities of approximately 60 mA/cm 2.

  16. The fast rate limit of driven diffusive systems

    Science.gov (United States)

    Krug, J.; Lebowitz, J. L.; Spohn, H.; Zhang, M. Q.

    1986-08-01

    We study the stationary nonequilibrium states of the van Beijeren/Schulman model of a driven lattice gas in two dimensions. In this model, jumps are much faster in the direction of the driving force than orthogonal to it. Van Kampen's Ω-expansion provides a suitable description of the model in the high-temperature region and specifies the critical temperature and the spinodal curve. We find the rate dependence of T c and show that independently of the jump rates the critical exponents of the transition are classical, except for anomalous energy fluctuations. We then study the stationary solution of the deterministic equations (zeroth-order Ω-expansion). They can be obtained as trajectories of a dissipative dynamical system with a three-dimensional phase space. Within a certain temperature range below T c, these equations have a kink solution whose asymptotic densities we identify with those of phase coexistence. They appear to coincide with the results of the "Maxwell construction." This provides a dynamical justification for the use of this construction in this nonequilibrium model. The relation of the Freidlin-Wentzell theory of small random perturbations of dynamical systems to the steady-state distribution below T c is discussed.

  17. submitter Data-driven RBE parameterization for helium ion beams

    CERN Document Server

    Mairani, A; Dokic, I; Valle, S M; Tessonnier, T; Galm, R; Ciocca, M; Parodi, K; Ferrari, A; Jäkel, O; Haberer, T; Pedroni, P; Böhlen, T T

    2016-01-01

    Helium ion beams are expected to be available again in the near future for clinical use. A suitable formalism to obtain relative biological effectiveness (RBE) values for treatment planning (TP) studies is needed. In this work we developed a data-driven RBE parameterization based on published in vitro experimental values. The RBE parameterization has been developed within the framework of the linear-quadratic (LQ) model as a function of the helium linear energy transfer (LET), dose and the tissue specific parameter ${{(\\alpha /\\beta )}_{\\text{ph}}}$ of the LQ model for the reference radiation. Analytic expressions are provided, derived from the collected database, describing the $\\text{RB}{{\\text{E}}_{\\alpha}}={{\\alpha}_{\\text{He}}}/{{\\alpha}_{\\text{ph}}}$ and ${{\\text{R}}_{\\beta}}={{\\beta}_{\\text{He}}}/{{\\beta}_{\\text{ph}}}$ ratios as a function of LET. Calculated RBE values at 2 Gy photon dose and at 10% survival ($\\text{RB}{{\\text{E}}_{10}}$ ) are compared with the experimental ones. Pearson's correlati...

  18. Methods to determine fast-ion distribution functions from multi-diagnostic measurements

    DEFF Research Database (Denmark)

    Jacobsen, Asger Schou; Salewski, Mirko

    Understanding the behaviour of fast ions in a fusion plasma is very important, since the fusion-born alpha particles are expected to be the main source of heating in a fusion power plant. Preferably, the entire fast-ion velocity-space distribution function would be measured. However, no fast...

  19. Li mobility in fast ion conductors followed by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, J.

    2010-07-01

    Structural features that enhance Li mobility in fast ion conductors with perovskite (Li{sub 3}xLa{sub 2}/3-xTiO{sub 3} series) and Nasicon structure (Li{sub 1}+xTi{sub 2}-xAl{sub x} (PO{sub 4}){sub 3} series) have been investigated. From the analysis of quadrupolar interactions, the local symmetry and exchange processes between structural sites occupied by lithium have been deduced to investigate local motions of lithium in conduction paths of analyzed compounds. The study of spin-lattice (T{sub 1}) and spin-spin (T{sub 2}) relaxation times made possible the analysis of the temperature dependence of Li residence times at structural sites. The comparison of these values with those deduced from conductivity (ac and dc-measurements) allowed the study of Li-motion mechanisms. The onset of long range motions requires the analysis of low frequency measurements (T{sub 2} relaxation and dc-conductivity). The non- Arrhenius behaviour, often observed in fast ion conductors, has been ascribed to order/disorder transitions. At increasing temperatures, Li motions become less correlated, producing the decrement of activation energy. In analyzed compounds, a direct measurement of diffusion coefficients has been obtained from NMR experiments performed with the pulse field gradient (PFG) technique. Finally, it is emphasized the importance of the vacancy percolation in conductivity processes. (Author)

  20. Modeling Fast Ion Transport in TAE Avalanches in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, E D; Bell, R E; Darrow, D; Gorelenkov, N N; Kramer, G; Kubota, S; Levinton, F M; Liu, D; Medley, S S; Podesta, M; Tritz, K

    2009-08-17

    Experiments on the National Spherical Torus Experiment [M. Ono, et al., Nucl. Fusion 40 (2000) 557 ] have found strong bursts of Toroidal Alfven Eigenmode (TAE) activity correlated with abrupt drops in the neutron rate. A fairly complete data set offers the opportunity to benchmark the NOVA [C. Z. Cheng, Phys. Reports 211, 1-51 (1992)] and ORBIT [R. B. White and M. S. Chance, Phys. Fluids 27, 2455 (1984)] codes in the low aspect ratio tokamak (ST) geometry. The internal structure of TAE were modeled with NOVA and good agreement is found with measurements made with an array of five fixed-frequency reflectometers. The fast-ion transport resulting from these bursts of multiple TAE were then modeled with the ORBIT code. The simulations are reasonably consistent with the observed drop in neutron rate. While these results represent our best attempts to find agreement, we believe that further refinements in both the simulation of the TAE structure and in the modeling of the fast ion transport are needed. Benchmarking stability codes against present experiments is an important step in developing the predictive capability needed to plan future experiments.

  1. Z-petawatt driven ion beam radiography development.

    Energy Technology Data Exchange (ETDEWEB)

    Schollmeier, Marius; Geissel, Matthias; Rambo, Patrick K.; Schwarz, Jens; Sefkow, Adam B.

    2013-09-01

    Laser-driven proton radiography provides electromagnetic field mapping with high spatiotemporal resolution, and has been applied to many laser-driven High Energy Density Physics (HEDP) experiments. Our report addresses key questions about the feasibility of ion radiography at the Z-Accelerator (%E2%80%9CZ%E2%80%9D), concerning laser configuration, hardware, and radiation background. Charged particle tracking revealed that radiography at Z requires GeV scale protons, which is out of reach for existing and near-future laser systems. However, it might be possible to perform proton deflectometry to detect magnetic flux compression in the fringe field region of a magnetized liner inertial fusion experiment. Experiments with the Z-Petawatt laser to enhance proton yield and energy showed an unexpected scaling with target thickness. Full-scale, 3D radiation-hydrodynamics simulations, coupled to fully explicit and kinetic 2D particle-in-cell simulations running for over 10 ps, explain the scaling by a complex interplay of laser prepulse, preplasma, and ps-scale temporal rising edge of the laser.

  2. Effects of Ions Charge-Mass Ratio on Energy and Energy Spread of Accelerated Ions in Laser Driven Plasma

    Institute of Scientific and Technical Information of China (English)

    SANG Hai-Bo; DENG Shi-Qiang; XIE Bai-Song

    2013-01-01

    Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong laser.The radiation pressure acceleration mechanism plays an important role on the studied problem.For the ions near the plasma mirror,i.e.electrons layer,the dependence of ions energy on their charge-mass ratio is derived theoretically.It is found that the larger the charge-mass ratio is,the higher the accelerated ions energy gets.For those ions far away from the layer,the dependence of energy and energy spread on ions charge-mass ratio are also obtained by numerical performance.It exhibits that,as ions charge-mass ratio increases,not only the accelerated ions energy but also the energy spread will become large.

  3. Elastic wave from fast heavy ion irradiation on solids

    CERN Document Server

    Kambara, T; Kanai, Y; Kojima, T M; Nanai, Y; Yoneda, A; Yamazaki, Y

    2002-01-01

    To study the time-dependent mechanical effects of fast heavy ion irradiations, we have irradiated various solids by a short-bunch beam of 95 MeV/u Ar ions and observed elastic waves generated in the bulk. The irradiated targets were square-shaped plates of poly-crystals of metals (Al and Cu), invar alloy, ceramic (Al sub 2 O sub 3), fused silica (SiO sub 2) and single crystals of KC1 and LiF with a thickness of 10 mm. The beam was incident perpendicular to the surface and all ions were stopped in the target. Two piezo-electric ultrasonic sensors were attached to the surface of the target and detected the elastic waves. The elastic waveforms as well as the time structure and intensity of the beam bunch were recorded for each shot of a beam bunch. The sensor placed opposite to the beam spot recorded a clear waveform of the longitudinal wave across the material, except for the invar and fused silica targets. From its propagation time along with the sound velocity and the thickness of the target, the depth of the...

  4. rf-driven ion sources for industrial applications (invited) (abstract)a)

    Science.gov (United States)

    Leung, Ka-Ngo

    2008-02-01

    The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory have been developing rf-driven ion sources for the last two decades. These sources are being used to generate both positive and negative ion beams. Some of these sources are operating in particle accelerators such as the Spallation Neutron Source (SNS) at Oak Ridge, while others are being employed in various industrial ion beam systems. There are four areas where the rf-driven ion sources are commonly used in industry. (1) In semiconductor manufacturing, rf-driven sources have found important applications in plasma etching, ion beam implantation, and ion beam lithography. (2) In material analysis and surface modification, miniature rf-ion sources can be found in focused ion beam systems. They can provide ion beams of essentially any element in the Periodic Table. The newly developed combined rf ion-electron beam unit improves greatly the performance of the secondary ion mass spectrometry tool. (3) For neutron production, rf ion source is a major component of compact, high flux D-D, D-T, or T-T neutron generators. These neutron sources are now being employed in boron neutron capture therapy (BNCT) as well as in neutron imaging and material interrogation. (4) Large area rf-driven ion source will be used in an industrial design neutral beam diagnostic system for probing fusion plasmas. Such sources can be easily scaled to provide large ion beam current for future fusion reactor applications.

  5. Understanding the growth rate patterns of ion Bernstein instabilities driven by ring-like proton velocity distributions

    Science.gov (United States)

    Min, Kyungguk; Liu, Kaijun

    2016-04-01

    Fast magnetosonic waves in Earth's inner magnetosphere, which have as their source ion Bernstein instabilities, are driven by hot proton velocity distributions (fp) with ∂fp(v⊥)/∂v⊥>0. Two typical types of distributions with such features are ring and shell velocity distributions. Both have been used in studies of ion Bernstein instabilities and fast magnetosonic waves, but the differences between instabilities driven by the two types of distributions have not been thoroughly addressed. The present study uses linear kinetic theory to examine and understand these differences. It is found that the growth rate pattern is primarily determined by the cyclotron resonance condition and the structure of the velocity distribution in gyroaveraged velocity space. For ring-driven Bernstein instabilities, as the parallel wave number (k∥) increases, the discrete unstable modes approximately follow the corresponding proton cyclotron harmonic frequencies while they become broader in frequency space. At sufficiently large k∥, the neighboring discrete modes merge into a continuum. In contrast, for shell-driven Bernstein instabilities, the curved geometry of the shell velocity distribution in gyroaveraged velocity space results in a complex alternating pattern of growth and damping rates in frequency and wave number space and confines the unstable Bernstein modes to relatively small k∥. In addition, when k∥ increases, the unstable modes are no longer limited to the proton cyclotron harmonic frequencies. The local growth rate peak near an exact harmonic at small k∥ bifurcates into two local peaks on both sides of the harmonic when k∥ becomes large.

  6. Magnetic compressibility and ion-temperature-gradient-driven microinstabilities in magnetically confined plasmas

    CERN Document Server

    Zocco, A; Connor, J W

    2015-01-01

    The electromagnetic theory of the strongly driven ion-temperature-gradient (ITG) instability in magnetically confined toroidal plasmas is developed. Stabilizing and destabilizing effects are identified, and a critical $\\beta_{e}$ (the ratio of the electron to magnetic pressure) for stabilization of the toroidal branch of the mode is calculated for magnetic equilibria independent of the coordinate along the magnetic field. Its scaling is $\\beta_{e}\\sim L_{Te}/R,$ where $L_{Te}$ is the characteristic electron temperature gradient length, and $R$ the major radius of the torus. We conjecture that a fast particle population can cause a similar stabilization due to its contribution to the equilibrium pressure gradient. For sheared equilibria, the boundary of marginal stability of the electromagnetic correction to the electrostatic mode is also given. For a general magnetic equilibrium, we find a critical length (for electromagnetic stabilization) of the extent of the unfavourable curvature along the magnetic field....

  7. Fast ion dynamics in ASDEX upgrade and TEXTOR measured by collective Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Moseev, D.

    2011-11-15

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is sensitive to the projection of fast ion velocity distribution function. This thesis is mainly devoted to investigations of fast ion physics in tokamak plasmas by means of CTS. (Author)

  8. Analysis of fast ion induced instabilities in tokamak plasmas

    CERN Document Server

    Horváth, László

    2015-01-01

    In magnetic confinement fusion devices like tokamaks, it is crucial to confine the high energy fusion-born helium nuclei ($\\alpha$-particles) to maintain the energy equilibrium of the plasma. However, energetic ions can excite various instabilities which can lead to their enhanced radial transport. Consequently, these instabilities may degrade the heating efficiency and they can also cause harmful power loads on the plasma-facing components of the device. Therefore, the understanding of these modes is a key issue regarding future burning plasma experiments. One of the main open questions concerning energetic particle (EP) driven instabilities is the non-linear evolution of the mode structure. In this thesis, I present my results on the investigation of $\\beta$-induced Alfv\\'{e}n eigenmodes (BAEs) and EP-driven geodesic acoustic modes (EGAMs) observed in the ramp-up phase of off-axis NBI heated plasmas in the ASDEX Upgrade tokamak. These modes were well visible on several line-of-sights (LOSs) of the soft X-ra...

  9. Gyrokinetic electron and fully kinetic ion simulations of fast magnetosonic waves in the magnetosphere

    Science.gov (United States)

    Gao, Xiaotian; Liu, Kaijun; Wang, Xueyi; Min, Kyungguk; Lin, Yu; Wang, Xiaogang

    2017-06-01

    Two-dimensional simulations using a gyrokinetic electron and fully kinetic ion (GeFi) scheme are preformed to study the excitation of fast magnetosonic waves in the terrestrial magnetosphere, which arise from the ion Bernstein instability driven by proton velocity distributions with a positive slope with respect to the perpendicular velocity. Since both ion and electron kinetics are relevant, particle-in-cell (PIC) simulations have often been employed to study the wave excitation. However, the full particle-in-cell scheme is computationally expensive for simulating waves in the ion scale because the electron scale must be fully resolved. Therefore, such simulations are limited to reduced proton-to-electron mass ratio ( m p / m e) and light-to-Alfvén speed ratio ( c / v A). The present study exploits the GeFi scheme that can break through these limitations to some extent, so larger m p / m e and c / v A can be used. In the simulations presented, the ion Bernstein instability is driven by a proton velocity distribution composed of 10% energetic protons with a shell distribution and 90% relatively cool, background protons with a Maxwellian distribution. The capability of the GeFi code in simulating the ion Bernstein instability is first demonstrated by comparing a GeFi simulation using reduced mass ratio ( m p / m e = 100) and speed ratio ( c / v A = 15) to a corresponding PIC simulation as well as linear dispersion analysis. A realistic speed ratio ( c / v A = 400) and a larger mass ratio ( m p / m e = 400) are then adopted in the GeFi code to explore how the results vary. It is shown that, as the increased m p / m e and c / v A lead to a larger lower hybrid frequency, ion Bernstein waves are excited at more ion cyclotron harmonics, consistent with the general prediction of linear dispersion theory. On the other hand, the GeFi simulations also revealed some interesting features after the instability saturation, which are likely related to nonlinear wave

  10. Developments of fast emittance monitors for ion sources at RCNP

    Science.gov (United States)

    Yorita, T.; Hatanaka, K.; Fukuda, M.; Shimada, K.; Yasuda, Y.; Saito, T.; Tamura, H.; Kamakura, K.

    2016-02-01

    Recently, several developments of low energy beam transport line and its beam diagnostic systems have been performed to improve the injection efficiency of ion beam to azimuthally varying field cyclotron at Research Center for Nuclear Physics, Osaka University. One of those is the fast emittance monitor which can measure within several seconds for the efficient beam development and a Pepper-Pot Emittance Monitor (PPEM) has been developed. The PPEM consists of pepper-pot mask, multichannel plate, fluorescent screen, mirror, and CCD camera. The CCD image is taken via IEEE1394b to a personal computer and analyzed immediately and frequently, and then real time measurement with about 2 Hz has been achieved.

  11. Developments of fast emittance monitors for ion sources at RCNP

    Energy Technology Data Exchange (ETDEWEB)

    Yorita, T., E-mail: yorita@rcnp.osaka-u.ac.jp; Hatanaka, K.; Fukuda, M.; Shimada, K.; Yasuda, Y.; Saito, T.; Tamura, H.; Kamakura, K. [Research Center for Nuclear Physics (RCNP), Osaka University, Osaka 567-0047 (Japan)

    2016-02-15

    Recently, several developments of low energy beam transport line and its beam diagnostic systems have been performed to improve the injection efficiency of ion beam to azimuthally varying field cyclotron at Research Center for Nuclear Physics, Osaka University. One of those is the fast emittance monitor which can measure within several seconds for the efficient beam development and a Pepper-Pot Emittance Monitor (PPEM) has been developed. The PPEM consists of pepper-pot mask, multichannel plate, fluorescent screen, mirror, and CCD camera. The CCD image is taken via IEEE1394b to a personal computer and analyzed immediately and frequently, and then real time measurement with about 2 Hz has been achieved.

  12. Modelling of advanced three-ion ICRF heating and fast ion generation scheme for tokamaks and stellarators

    Science.gov (United States)

    Faustin, J. M.; Graves, J. P.; Cooper, W. A.; Lanthaler, S.; Villard, L.; Pfefferlé, D.; Geiger, J.; Kazakov, Ye O.; Van Eester, D.

    2017-08-01

    Absorption of ion-cyclotron range of frequencies waves at the fundamental resonance is an efficient source of plasma heating and fast ion generation in tokamaks and stellarators. This heating method is planned to be exploited as a fast ion source in the Wendelstein 7-X stellarator. The work presented here assesses the possibility of using the newly developed three-ion species scheme (Kazakov et al (2015) Nucl. Fusion 55 032001) in tokamak and stellarator plasmas, which could offer the capability of generating more energetic ions than the traditional minority heating scheme with moderate input power. Using the SCENIC code, it is found that fast ions in the MeV range of energy can be produced in JET-like plasmas. The RF-induced particle pinch is seen to strongly impact the fast ion pressure profile in particular. Our results show that in typical high-density W7-X plasmas, the three-ion species scheme generates more energetic ions than the more traditional minority heating scheme, which makes three-ion scenario promising for fast-ion confinement studies in W7-X.

  13. Anomalous fast ion losses at high β on the tokamak fusion test reactor

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, E. D.; Bell, M. G.; Budny, R. V.; Darrow, D. S.; White, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2015-03-15

    This paper describes experiments carried out on the Tokamak Fusion Test Reactor (TFTR) [R. J. Hawryluk et al., Plasma Phys. Controlled Fusion 33, 1509 (1991)] to investigate the dependence of β-limiting disruption characteristics on toroidal field strength. The hard disruptions found at the β-limit in high field plasmas were not found at low field, even for β's 50% higher than the empirical β-limit of β{sub n} ≈ 2 at high field. Comparisons of experimentally measured β's to TRANSP simulations suggest anomalous loss of up to half of the beam fast ions in the highest β, low field shots. The anomalous transport responsible for the fast ion losses may at the same time broaden the pressure profile. Toroidal Alfvén eigenmodes, fishbone instabilities, and Geodesic Acoustic Modes are investigated as possible causes of the enhanced losses. Here, we present the first observations of high frequency fishbones [F. Zonca et al., Nucl. Fusion 49, 085009 (2009)] on TFTR. The interpretation of Axi-symmetric Beam-driven Modes as Geodesic Acoustic Modes and their possible correlation with transport barrier formation are also presented.

  14. Asymmetric Functional Conversion of Eubacterial Light-driven Ion Pumps.

    Science.gov (United States)

    Inoue, Keiichi; Nomura, Yurika; Kandori, Hideki

    2016-05-06

    In addition to the well-known light-driven outward proton pumps, novel ion-pumping rhodopsins functioning as outward Na(+) and inward Cl(-) pumps have been recently found in eubacteria. They convert light energy into transmembrane electrochemical potential difference, similar to the prototypical archaeal H(+) pump bacteriorhodopsin (BR) and Cl(-) pump halorhodopsin (HR). The H(+), Na(+), and Cl(-) pumps possess the conserved respective DTE, NDQ, and NTQ motifs in the helix C, which likely serve as their functional determinants. To verify this hypothesis, we attempted functional interconversion between selected pumps from each category by mutagenesis. Introduction of the proton-pumping motif resulted in successful Na(+) → H(+) functional conversion. Introduction of the respective characteristic motifs with several additional mutations leads to successful Na(+) → Cl(-) and Cl(-) → H(+) functional conversions, whereas remaining conversions (H(+) → Na(+), H(+) → Cl(-), Cl(-) → Na(+)) were unsuccessful when mutagenesis of 4-6 residues was used. Phylogenetic analysis suggests that a H(+) pump is the common ancestor of all of these rhodopsins, from which Cl(-) pumps emerged followed by Na(+) pumps. We propose that successful functional conversions of these ion pumps are achieved exclusively when mutagenesis reverses the evolutionary amino acid sequence changes. Dependence of the observed functional conversions on the direction of evolution strongly suggests that the essential structural mechanism of an ancestral function is retained even after the gain of a new function during natural evolution, which can be evoked by a few mutations. By contrast, the gain of a new function needs accumulation of multiple mutations, which may not be easily reproduced by limited mutagenesis in vitro.

  15. Quantitative evaluation of wall heat loads by lost fast ions in the Large Helical Device

    Science.gov (United States)

    Morimoto, Junki; Suzuki, Yasuhiro; Seki, Ryosuke

    2016-10-01

    In fusion plasmas, fast ions are produced by neutral beam injections (NBI), ion cyclotron heating (ICH) and fusion reactions. Some of fast ions are lost from fusion plasmas because of some kinds of drift and instability. These lost fast ions may cause damages on plasma facing components such as divertors and diagnostic instruments in fusion reactors. Therefore, wall heat loads by lost fast ions in the Large Helical Device (LHD) is under investigation. For this purpose, we have been developing the Monte-Carlo code for the quantitative evaluation of wall heat loads based on following the guiding center orbits of fast ions. Using this code, we investigate wall heat loads and hitting points of lost fast ions produced by NBI in LHD. Magnetic field configurations, which depend on beta values, affect orbits of fast ions and wall heat loads. Therefore, the wall heat loads by fast ions in equilibrium magnetic fields including finite beta effect and magnetic islands are quantitatively evaluated. The differences of wall heat loads and particle deposition patterns for cases of the vacuum field and various beta equilibrium fields will be presented at the meeting.

  16. Ion acceleration by petawatt class laser pulses and pellet compression in a fast ignition scenario

    Energy Technology Data Exchange (ETDEWEB)

    Benedetti, C. [Dipartimento di Fisica, Universita di Bologna, INFN sezione di Bologna (Italy)], E-mail: benedetti@bo.infn.it; Londrillo, P. [Dipartimento di Astronomia, Universita di Bologna, INAF sezione di Bologna, INFN sezione di Bologna (Italy); Liseykina, T.V. [Institute for Computational Technologies, SD-RAS, Novosibirsk (Russian Federation); Max-Planck-Institute for Nuclear Physics, Heidelberg (Germany); Macchi, A. [polyLAB, CNR-INFM, Pisa (Italy); Sgattoni, A.; Turchetti, G. [Dipartimento di Fisica, Universita di Bologna, INFN sezione di Bologna (Italy)

    2009-07-11

    Ion drivers based on standard acceleration techniques have faced up to now several difficulties. We consider here a conceptual alternative to more standard schemes, such as HIDIF (Heavy Ion Driven Inertial Fusion), which are still beyond the present state of the art of particle accelerators, even though the requirements on the total beam energy are lowered by fast ignition scenarios. The new generation of petawatt class lasers open new possibilities: acceleration of electrons or protons for the fast ignition and eventually light or heavy ions acceleration for compression. The pulses of chirped pulse amplification (CPA) lasers allow ions acceleration with very high efficiency at reachable intensities (I{approx}10{sup 21}W/cm{sup 2}), if circularly polarized light is used since we enter in the radiation pressure acceleration (RPA) regime. We analyze the possibility of accelerating carbon ion bunches by interaction of a circularly polarized pulses with an ultra-thin target. The advantage would be compactness and modularity, due to identical accelerating units. The laser efficiency required to have an acceptable net gain in the inertial fusion process is still far from the presently achievable values both for CPA short pulses and for long pulses used for direct illumination. Conversely the energy conversion efficiency from the laser pulse to the ion bunch is high and grows with the intensity. As a consequence the energy loss is not the major concern. For a preliminary investigation of the ions bunch production we have used the PIC code ALaDyn developed to analyze the results of the INFN-CNR PLASMONX experiment at Frascati National Laboratories (Rome, Italy) where the 0.3 PW laser FLAME will accelerate electrons and protons. We present the results of some 1D simulations and parametric scan concerning the acceleration of carbon ions that we suppose to be fully ionized. Circularly polarized laser pulses of 50 J and 50-100 fs duration, illuminating a 100{mu}m{sup 2} area

  17. LEEM investigations of clean surfaces driven by energetic ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Abbamonte, Peter M. [University of Illinois

    2013-04-24

    The original purpose of this award was to use low‐energy electron microscopy (LEEM) to explore the dynamics of surfaces of clean single crystal surfaces when driven by a beam of energetic ions. The goal was to understand the nanoscience of hyperthermal growth, surface erosion by sublimation and irradiation, operation of surface sinks in irradiated materials, diffusion on driven surfaces, and the creation of structural patterns. This project was based on a novel LEEM system constructed by C. P. Flynn, which provided real‐time imaging of surface dynamics by scattering low energy electrons. With the passing of Prof. Flynn in late 2011, this project was completed under a slightly different scope by constructing a low‐energy, inelastic electron scattering (EELS) instrument. Consistent with Flynn's original objectives for his LEEM system, this device probes the dynamics of crystal surfaces. However the measurements are not carried out in real time, but instead are done in the frequency domain, through the energy lost from the probe electrons. The purpose of this device is to study the collective bosonic excitations in a variety of materials, including high temperature superconductors, topological insulators, carbon allotropes including (but not limited to) graphene, etc. The ultimate goal here is to identify the bosons that mediate interactions in these and other materials, with hopes of shedding light on the origin of many exotic phenomena including high temperature superconductivity. We completed the construction of a low‐energy EELS system that operates with an electron kinetic energy of 7 - 10 eV. With this instrument now running, we hope to identify, among other things, the bosons that mediate pairing in high temperature superconductors. Using this instrument, we have already made our first discovery. Studying freshly cleaved single crystals of Bi{sub 2}Se{sub 3}, which is a topological insulator, we have observed a surface excitation at an energy loss

  18. Antenna design for fast ion collective Thomson scattering diagnostic for the international thermonuclear experimental reactor

    DEFF Research Database (Denmark)

    Leipold, Frank; Furtula, Vedran; Salewski, Mirko

    2009-01-01

    Fast ion physics will play an important role for the international thermonuclear experimental reactor (ITER), where confined alpha particles will affect and be affected by plasma dynamics and thereby have impacts on the overall confinement. A fast ion collective Thomson scattering (CTS) diagnostic...

  19. Fast ion collective Thomson scattering - present results and plans for ITER

    DEFF Research Database (Denmark)

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

    scattering (CTS) provides the possibility of revealing the velocity distribution of the confined fast ions along a given direction – resolved both in time and space. Recently, the ITER baseline design has been expanded to include a fast ion CTS diagnostic. The design of this diagnostic was provided...... and results, and present the expectations for the ITER CTS diagnostic....

  20. High-definition velocity-space tomography of fast-ion dynamics

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Jacobsen, A.S.

    2016-01-01

    Velocity-space tomography of the fast-ion distribution function in a fusion plasma is usually a photon-starved tomography method due to limited optical access and signal-to-noise ratio of fast-ion Dα (FIDA) spectroscopy as well as the strive for high-resolution images. In high-definition tomograp...

  1. Fast-ion transport and neutral beam current drive in ASDEX upgrade

    DEFF Research Database (Denmark)

    Geiger, B.; Weiland, M.; Jacobsen, Asger Schou

    2015-01-01

    The neutral beam current drive efficiency has been investigated in the ASDEX Upgrade tokamak by replacing on-axis neutral beams with tangential off-axis beams. A clear modification of the radial fast-ion profiles is observed with a fast-ion D-alpha diagnostic that measures centrally peaked profil...

  2. Tomography of fast-ion velocity-space distributions from synthetic CTS and FIDA measurements

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Nielsen, Stefan Kragh;

    2012-01-01

    We compute tomographies of 2D fast-ion velocity distribution functions from synthetic collective Thomson scattering (CTS) and fast-ion D (FIDA) 1D measurements using a new reconstruction prescription. Contradicting conventional wisdom we demonstrate that one single 1D CTS or FIDA view suffices to...

  3. On velocity space interrogation regions of fast-ion collective Thomson scattering at ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Nielsen, Stefan Kragh; Bindslev, Henrik;

    2011-01-01

    The collective Thomson scattering (CTS) diagnostic proposed for ITER is designed to measure projected 1D fast-ion velocity distribution functions at several spatial locations simultaneously. The frequency shift of scattered radiation and the scattering geometry place fast ions that caused the col...

  4. Combination of fast-ion diagnostics in velocity-space tomographies

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Nielsen, Stefan Kragh

    2013-01-01

    Fast-ion Dα (FIDA) and collective Thomson scattering (CTS) diagnostics provide indirect measurements of fast-ion velocity distribution functions in magnetically confined plasmas. Here we present the first prescription for velocity-space tomographic inversion of CTS and FIDA measurements that can ...

  5. Investigation of fast ion pressure effects in ASDEX Upgrade by spectral MSE measurements

    Science.gov (United States)

    Reimer, René; Dinklage, Andreas; Wolf, Robert; Dunne, Mike; Geiger, Benedikt; Hobirk, Jörg; Reich, Matthias; ASDEX Upgrade Team; McCarthy, Patrick J.

    2017-04-01

    High precision measurements of fast ion effects on the magnetic equilibrium in the ASDEX Upgrade tokamak have been conducted in a high-power (10 MW) neutral-beam injection discharge. An improved analysis of the spectral motional Stark effect data based on forward-modeling, including the Zeeman effect, fine-structure and non-statistical sub-level distribution, revealed changes in the order of 1% in |B| . The results were found to be consistent with results from the equilibrium solver CLISTE. The measurements allowed us to derive the fast ion pressure fraction to be Δ {{p}\\text{FI}}/{{p}\\text{mhd}}≈ 10 % and variations of the fast ion pressure are consistent with calculations of the transport code TRANSP. The results advance the understanding of fast ion confinement and magneto-hydrodynamic stability in the presence of fast ions.

  6. Time-driven Activity-based Cost of Fast-Track Total Hip and Knee Arthroplasty

    DEFF Research Database (Denmark)

    Andreasen, Signe E; Holm, Henriette B; Jørgensen, Mira

    2017-01-01

    this between 2 departments with different logistical set-ups. METHODS: Prospective data collection was analyzed using the time-driven activity-based costing method (TDABC) on time consumed by different staff members involved in patient treatment in the perioperative period of fast-track THA and TKA in 2 Danish...... orthopedic departments with standardized fast-track settings, but different logistical set-ups. RESULTS: Length of stay was median 2 days in both departments. TDABC revealed minor differences in the perioperative settings between departments, but the total cost excluding the prosthesis was similar at USD......-track methodology, the result could be a more cost-effective pathway altogether. As THA and TKA are potentially costly procedures and the numbers are increasing in an economical limited environment, the aim of this study is to present baseline detailed economical calculations of fast-track THA and TKA and compare...

  7. Spot heating calculation for a heavy ion driven high temperature experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E.P.; Mark, J.W.K.

    1984-04-01

    An analytical model is used to predict the temperature reached in a spot heating experiment driven by a heavy ion beam. A discussion of physical processes and approximations is included. 10 references, 9 figures, 3 tables.

  8. Filamentation instability of current-driven dust ion-acoustic waves in a collisional dusty plasma

    Energy Technology Data Exchange (ETDEWEB)

    Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 19839-63113 (Iran, Islamic Republic of); Haghtalab, T.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand 97179-63384 (Iran, Islamic Republic of)

    2011-11-15

    A theoretical investigation has been made of the dust ion-acoustic filamentation instability in an unmagnetized current-driven dusty plasma by using the Lorentz transformation formulas. The effect of collision between the charged particles with neutrals and their thermal motion on this instability is considered. Developing the filamentation instability of the current-driven dust ion-acoustic wave allows us to determine the period and the establishment time of the filamentation structure and threshold for instability development.

  9. Radiation hydrodynamic simulations of line-driven disk winds for ultra-fast outflows

    Science.gov (United States)

    Nomura, Mariko; Ohsuga, Ken; Takahashi, Hiroyuki R.; Wada, Keiichi; Yoshida, Tessei

    2016-02-01

    Using two-dimensional radiation hydrodynamic simulations, we investigate the origin of the ultra-fast outflows (UFOs) that are often observed in luminous active galactic nuclei (AGNs). We found that the radiation force due to the spectral lines generates strong winds (line-driven disk winds) that are launched from the inner region of accretion disks (˜30 Schwarzschild radii). A wide range of black hole masses (MBH) and Eddington ratios (ε) was investigated to study the conditions causing the line-driven winds. For MBH = 106-109 M⊙ and ε = 0.1-0.7, funnel-shaped disk winds appear, in which dense matter is accelerated outward with an opening angle of 70°-80° and with 10% of the speed of light. If we observe the wind along its direction, the velocity, the column density, and the ionization state are consistent with those of the observed UFOs. As long as obscuration by the torus does not affect the observation of X-ray bands, the UFOs could be statistically observed in about 13%-28% of the luminous AGNs, which is not inconsistent with the observed ratio (˜40%). We also found that the results are insensitive to the X-ray luminosity and the density of the disk surface. Thus, we can conclude that UFOs could exist in any luminous AGNs, such as narrow-line Seyfert 1s and quasars with ε > 0.1, with which fast line-driven winds are associated.

  10. Time-driven Activity-based Cost of Fast-Track Total Hip and Knee Arthroplasty.

    Science.gov (United States)

    Andreasen, Signe E; Holm, Henriette B; Jørgensen, Mira; Gromov, Kirill; Kjærsgaard-Andersen, Per; Husted, Henrik

    2017-06-01

    Fast-track total hip and knee arthroplasty (THA and TKA) has been shown to reduce the perioperative convalescence resulting in less postoperative morbidity, earlier fulfillment of functional milestones, and shorter hospital stay. As organizational optimization is also part of the fast-track methodology, the result could be a more cost-effective pathway altogether. As THA and TKA are potentially costly procedures and the numbers are increasing in an economical limited environment, the aim of this study is to present baseline detailed economical calculations of fast-track THA and TKA and compare this between 2 departments with different logistical set-ups. Prospective data collection was analyzed using the time-driven activity-based costing method (TDABC) on time consumed by different staff members involved in patient treatment in the perioperative period of fast-track THA and TKA in 2 Danish orthopedic departments with standardized fast-track settings, but different logistical set-ups. Length of stay was median 2 days in both departments. TDABC revealed minor differences in the perioperative settings between departments, but the total cost excluding the prosthesis was similar at USD 2511 and USD 2551, respectively. Fast-track THA and TKA results in similar cost despite differences in the organizational set-up. Compared to cost associated with longer more conventional published pathways, fast-track is cheaper, which on top of the favorable published clinical outcome adds to cost efficiency and the potential for economic savings. Detailed baseline TDABC calculations are provided for comparison and further optimization of cost-benefit effectiveness. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Fast-ion Energy Loss During TAE Avalanches in the National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, E D; Darrow, D S; Gorelenkov, N N; Kramer, G J; Kubota, S; Podesta, M; White, R B; Bortolon, A; Gerhardt, S P; Bell, R E; Diallo, A; LeBlanc, B; Levinton, F M

    2012-07-11

    Strong TAE avalanches on NSTX, the National Spherical Torus Experiment [M. Ono, et al., Nucl. Fusion 40 (2000) 557] are typically correlated with drops in the neutron rate in the range of 5% - 15%. In previous studies of avalanches in L-mode plasmas, these neutron drops were found to be consistent with modeled losses of fast ions. Here we expand the study to TAE avalanches in NSTX H-mode plasmas with improved analysis techniques. At the measured TAE mode amplitudes, simulations with the ORBIT code predict that fast ion losses are negligible. However, the simulations predict that the TAE scatter the fast ions in energy, resulting in a small (≈ 6%) drop in fast ion β. The net decrease in energy of the fast ions is sufficient to account for the bulk of the drop in neutron rate, even in the absence of fast ion losses. This loss of energy from the fast ion population is comparable to the estimated energy lost by damping from the Alfven wave during the burst. The previously studied TAE avalanches in L-mode are re-evaluated using an improved calculation of the potential fluctuations in the ORBIT code.

  12. Improved Collective Thomson Scattering measurements of fast ions at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Rasmussen, Jesper; Nielsen, Stefan Kragh; Stejner Pedersen, Morten;

    2014-01-01

    Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation......Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson...... at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based...

  13. Consistency between real and synthetic fast-ion measurements at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Rasmussen, Jesper; Nielsen, Stefan Kragh; Pedersen, Morten Stejner

    2015-01-01

    by comparing fast-ion measurements from collective Thomson scattering, fast-ion spectroscopy, and neutron rate detectors with numerical predictions from the TRANSP/NUBEAM transport code. We also study the sensitivity of the theoretical predictions to uncertainties in the plasma kinetic profiles. We find...... that theory and measurements generally agree within these uncertainties for all three diagnostics during heating phases with either one or two neutral beam injection sources. This suggests that the measurements can be described by the same model assuming classical slowing down of fast ions. Since the three...

  14. Fast-ion transport in the presence of magnetic reconnection induced by sawtooth oscillations in ASDEX Upgrade

    NARCIS (Netherlands)

    Geiger, B.; Garcia-Munoz, M.; Dux, R.; Ryter, F.; Tardini, G.; Orte, L. B.; Classen, I.G.J.; Fable, E.; Fischer, R.; Igochine, V.; McDermott, R. M.

    2014-01-01

    The transport of beam-generated fast ions has been investigated experimentally at the ASDEX Upgrade tokamak in the presence of sawtooth crashes. After sawtooth crashes, phase space resolved fast-ion D-alpha measurements show a significant reduction of the central fast-ion density-more than 50%-toget

  15. A data-driven prediction method for fast-slow systems

    Science.gov (United States)

    Groth, Andreas; Chekroun, Mickael; Kondrashov, Dmitri; Ghil, Michael

    2016-04-01

    In this work, we present a prediction method for processes that exhibit a mixture of variability on low and fast scales. The method relies on combining empirical model reduction (EMR) with singular spectrum analysis (SSA). EMR is a data-driven methodology for constructing stochastic low-dimensional models that account for nonlinearity and serial correlation in the estimated noise, while SSA provides a decomposition of the complex dynamics into low-order components that capture spatio-temporal behavior on different time scales. Our study focuses on the data-driven modeling of partial observations from dynamical systems that exhibit power spectra with broad peaks. The main result in this talk is that the combination of SSA pre-filtering with EMR modeling improves, under certain circumstances, the modeling and prediction skill of such a system, as compared to a standard EMR prediction based on raw data. Specifically, it is the separation into "fast" and "slow" temporal scales by the SSA pre-filtering that achieves the improvement. We show, in particular that the resulting EMR-SSA emulators help predict intermittent behavior such as rapid transitions between specific regions of the system's phase space. This capability of the EMR-SSA prediction will be demonstrated on two low-dimensional models: the Rössler system and a Lotka-Volterra model for interspecies competition. In either case, the chaotic dynamics is produced through a Shilnikov-type mechanism and we argue that the latter seems to be an important ingredient for the good prediction skills of EMR-SSA emulators. Shilnikov-type behavior has been shown to arise in various complex geophysical fluid models, such as baroclinic quasi-geostrophic flows in the mid-latitude atmosphere and wind-driven double-gyre ocean circulation models. This pervasiveness of the Shilnikow mechanism of fast-slow transition opens interesting perspectives for the extension of the proposed EMR-SSA approach to more realistic situations.

  16. Laser-driven multicharged heavy ion beam acceleration

    Science.gov (United States)

    Nishiuchi, M.; Sakaki, H.; Esirkepov, T. Z.; Nishio, K.; Pikuz, T. A.; Faenov, A. Y.; Pirozhkov, A. S.; Sagisaka, A.; Ogura, K.; Kanasaki, M.; Kiriyama, H.; Fukuda, Y.; Kando, M.; Yamauchi, T.; Watanabe, Y.; Bulanov, S. V.; Kondo, K.; Imai, K.; Nagamiya, S.

    2015-05-01

    Experimental demonstration of multi-charged heavy ion acceleration from the interaction between the ultra-intense short pulse laser system and the metal target is presented. The laser pulse of ions accelerated up to 0.9 GeV are demonstrated. This is achieved by the high intensity laser field of ˜ 1021Wcm-2 interacting with the solid density target. The demonstrated iron ions with high charge to mass ratio (Q/M) is difficult to be achieved by the conventional heavy ion source technique in the accelerators.

  17. Influence of Alfven eigenmodes and ion cyclotron heating on the fast-ion distribution in the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Weiland, Markus; Geiger, Benedikt; Bilato, Roberto; Schneider, Philip; Tardini, Giovanni; Lauber, Philipp; Ryter, Francois; Schneller, Mirjam [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Collaboration: ASDEX Upgrade Team

    2015-05-01

    Fast, supra-thermal ions are created in the tokamak ASDEX Upgrade by neutral beam injection and ion cyclotron resonance heating (ICRH) and they are needed for plasma heating and current drive. A possibility to study them is the spectroscopic observation of line radiation (fast-ion D-alpha, FIDA), which emerges from charge exchange reactions. Here, the fast ions can be distinguished from the thermal particles through there strong Doppler-shift, and their radial density profile can be measured and compared to theoretical models. An analysis of the whole Doppler spectrum yields information about the 2D velocity distribution f(v {sub parallel}, v {sub perpendicular} {sub to}). Observation from different viewing angles allows consequently a tomographic reconstruction of f(v {sub parallel}, v {sub perpendicular} {sub to}). For this purpose, the FIDA diagnostic at ASDEX Upgrade has been extended from two to five views, and the spectrometer setup was improved to allow a simultaneous measurement of blue and red Doppler shifts. These recently developed diagnostic capabilities are used to study changes in the fast-ion distribution, which are caused by Alfven eigenmodes. Moreover, the further acceleration of fast ions through 2{sup nd} harmonic ICRH is investigated and compared to theoretical predictions.

  18. Ultrathin fibres from electrospinning experiments under driven fast-oscillating perturbations

    CERN Document Server

    Coluzza, Ivan; Gentili, Daniele; Pontrelli, Giuseppe; Succi, Sauro

    2014-01-01

    The effects of a driven fast-oscillating spinneret on the bending instability of electrified jets, leading to the formation of spiral structures in electrospinning experiments with charged polymers, are explored by means of extensive computer simulations. It is found that the morphology of the spirals can be placed in direct correspondence with the oscillation frequency and amplitude. In particular, by increasing the oscillation amplitude and frequency, thinner fibres can be extracted by the same polymer material, thereby opening design scenarios in electrospinning experiments.

  19. A Mechanism for Cytoplasmic Streaming: Kinesin-Driven Alignment of Microtubules and Fast Fluid Flows.

    Science.gov (United States)

    Monteith, Corey E; Brunner, Matthew E; Djagaeva, Inna; Bielecki, Anthony M; Deutsch, Joshua M; Saxton, William M

    2016-05-10

    The transport of cytoplasmic components can be profoundly affected by hydrodynamics. Cytoplasmic streaming in Drosophila oocytes offers a striking example. Forces on fluid from kinesin-1 are initially directed by a disordered meshwork of microtubules, generating minor slow cytoplasmic flows. Subsequently, to mix incoming nurse cell cytoplasm with ooplasm, a subcortical layer of microtubules forms parallel arrays that support long-range, fast flows. To analyze the streaming mechanism, we combined observations of microtubule and organelle motions with detailed mathematical modeling. In the fast state, microtubules tethered to the cortex form a thin subcortical layer and undergo correlated sinusoidal bending. Organelles moving in flows along the arrays show velocities that are slow near the cortex and fast on the inward side of the subcortical microtubule layer. Starting with fundamental physical principles suggested by qualitative hypotheses, and with published values for microtubule stiffness, kinesin velocity, and cytoplasmic viscosity, we developed a quantitative coupled hydrodynamic model for streaming. The fully detailed mathematical model and its simulations identify key variables that can shift the system between disordered (slow) and ordered (fast) states. Measurements of array curvature, wave period, and the effects of diminished kinesin velocity on flow rates, as well as prior observations on f-actin perturbation, support the model. This establishes a concrete mechanistic framework for the ooplasmic streaming process. The self-organizing fast phase is a result of viscous drag on kinesin-driven cargoes that mediates equal and opposite forces on cytoplasmic fluid and on microtubules whose minus ends are tethered to the cortex. Fluid moves toward plus ends and microtubules are forced backward toward their minus ends, resulting in buckling. Under certain conditions, the buckling microtubules self-organize into parallel bending arrays, guiding varying directions

  20. ECR-Driven Multicusp Volume H- Ion Source

    Science.gov (United States)

    Bacal, M.; Ivanov, A. A.; Rouillé, C.; Svarnas, P.; Béchu, S.; Pelletier, J.

    2005-04-01

    We studied the negative ion current extracted from the plasma created by seven elementary ECR sources, operating at 2.45 GHz, placed in the magnetic multipole chamber "Camembert III". We varied the pressure from 1 to 4 mTorr, with a maximum power of 1 kW and studied the plasma created in this system by measuring the various plasma parameters, including the density and temperature of the negative hydrogen ions. We found that the electron temperature is optimal for negative hydrogen ion production at 9.5 cm from the ECR sources. The tantalum-covered wall surface pollution reduces the extracted negative ion current and enhances the electron current. Tantalum evaporation has a positive effect. The use of a grid and of a collar in front of the plasma electrode did not lead to any enhancement of the extracted negative ion current.

  1. Collision induced fragmentation of fast molecular ions in solids and gases. [Review, wake effects, excited states

    Energy Technology Data Exchange (ETDEWEB)

    Gemmell, D S

    1979-01-01

    A brief review is given of recent high resolution measurements on fragments arising from the collision-induced dissociation of fast (MeV) molecular ions. For solid targets, strong wake effects are observed. For gaseous targets, excited electronic states of the projectile ions play an important role. Measurements of this type provide useful information on the charge states of fast ions traversing matter. The experimental techniques show promise as a unique method for determining the geometrical structures of the molecular-ion projectiles. 41 references.

  2. Fast Ion Dynamics in ASDEX Upgrade and TEXTOR Measured by Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Moseev, Dmitry

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic...

  3. Laser-driven shock acceleration of monoenergetic ion beams

    CERN Document Server

    Fiuza, F; Boella, E; Fonseca, R A; Silva, L O; Haberberger, D; Tochitsky, S; Gong, C; Mori, W B; Joshi, C

    2012-01-01

    We show that monoenergetic ion beams can be accelerated by moderate Mach number collisionless, electrostatic shocks propagating in a long scale-length exponentially decaying plasma profile. Strong plasma heating and density steepening produced by an intense laser pulse near the critical density can launch such shocks that propagate in the extended plasma at high velocities. The generation of a monoenergetic ion beam is possible due to the small and constant sheath electric field associated with the slowly decreasing density profile. The conditions for the acceleration of high-quality, energetic ion beams are identified through theory and multidimensional particle-in-cell simulations. The scaling of the ion energy with laser intensity shows that it is possible to generate $\\sim 200$ MeV proton beams with state-of-the-art 100 TW class laser systems.

  4. INERTIAL FUSION DRIVEN BY INTENSE HEAVY-ION BEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, W. M.; Friedman, A.; Grote, D. P.; Barnard, J. J.; Cohen, R. H.; Dorf, M. A.; Lund, S. M.; Perkins, L. J.; Terry, M. R.; Logan, B. G.; Bieniosek, F. M.; Faltens, A.; Henestroza, E.; Jung, J. Y.; Kwan, J. W.; Lee, E. P.; Lidia, S. M.; Ni, P. A.; Reginato, L. L.; Roy, P. K.; Seidl, P. A.; Takakuwa, J. H.; Vay, J.-L.; Waldron, W. L.; Davidson, R. C.; Gilson, E. P.; Kaganovich, I. D.; Qin, H.; Startsev, E.; Haber, I.; Kishek, R. A.; Koniges, A. E.

    2011-03-31

    Intense heavy-ion beams have long been considered a promising driver option for inertial-fusion energy production. This paper briefly compares inertial confinement fusion (ICF) to the more-familiar magnetic-confinement approach and presents some advantages of using beams of heavy ions to drive ICF instead of lasers. Key design choices in heavy-ion fusion (HIF) facilities are discussed, particularly the type of accelerator. We then review experiments carried out at Lawrence Berkeley National Laboratory (LBNL) over the past thirty years to understand various aspects of HIF driver physics. A brief review follows of present HIF research in the US and abroad, focusing on a new facility, NDCX-II, being built at LBNL to study the physics of warm dense matter heated by ions, as well as aspects of HIF target physics. Future research directions are briefly summarized.

  5. Alfv\\'en Wave Driven High Frequency Waves in the Solar Atmosphere: Implications for Ion Heating

    CERN Document Server

    Kaghashvili, Edisher Kh

    2014-01-01

    This work is an extension of Kaghashvili [1999] where ion-cyclotron wave dissipation channel for Alfv\\'en waves was discussed. While our earlier study dealt with the mode coupling in the commonly discussed sense, here we study changes in the initial waveform due to interaction of the initial driver Alfv\\'en wave and the plasma inhomogeneity, which are implicitly present in the equations, but were not elaborated in Kaghashvili [1999]. Using a cold plasma approximation, we show how high frequency waves (higher than the initial driver Alfv\\'en wave frequency) are generated in the inhomogeneous solar plasma flow. The generation of the high frequency forward and backward propagating modified fast magnetosonic/whistler waves as well as the generation of the driven Alfv\\'en waves is discussed in the solar atmosphere. The generated high frequency waves have a shorter dissipation timescale, and they can also resonant interact with particles using both the normal cyclotron and anomalous cyclotron interaction channels. ...

  6. Ion-driver fast ignition: Reducing heavy-ion fusion driver energy and cost, simplifying chamber design, target fab, tritium fueling and power conversion

    Energy Technology Data Exchange (ETDEWEB)

    Logan, G.; Callahan-Miller, D.; Perkins, J.; Caporaso, G.; Tabak, M.; Moir, R.; Meier, W.; Bangerter, Roger; Lee, Ed

    1998-04-01

    Ion fast ignition, like laser fast ignition, can potentially reduce driver energy for high target gain by an order of magnitude, while reducing fuel capsule implosion velocity, convergence ratio, and required precisions in target fabrication and illumination symmetry, all of which should further improve and simplify IFE power plants. From fast-ignition target requirements, we determine requirements for ion beam acceleration, pulse-compression, and final focus for advanced accelerators that must be developed for much shorter pulses and higher voltage gradients than today's accelerators, to deliver the petawatt peak powers and small focal spots ({approx}100 {micro}m) required. Although such peak powers and small focal spots are available today with lasers, development of such advanced accelerators is motivated by the greater likely efficiency of deep ion penetration and deposition into pre-compressed 1000x liquid density DT cores. Ion ignitor beam parameters for acceleration, pulse compression, and final focus are estimated for two examples based on a Dielectric Wall Accelerator; (1) a small target with {rho}r {approx} 2 g/cm{sup 2} for a small demo/pilot plant producing {approx}40 MJ of fusion yield per target, and (2) a large target with {rho}r {approx} 10 g/cm{sup 2} producing {approx}1 GJ yield for multi-unit electricity/hydrogen plants, allowing internal T-breeding with low T/D ratios, >75 % of the total fusion yield captured for plasma direct conversion, and simple liquid-protected chambers with gravity clearing. Key enabling development needs for ion fast ignition are found to be (1) ''Close-coupled'' target designs for single-ended illumination of both compressor and ignitor beams; (2) Development of high gradient (>25 MV/m) linacs with high charge-state (q {approx} 26) ion sources for short ({approx}5 ns) accelerator output pulses; (3) Small mm-scale laser-driven plasma lens of {approx}10 MG fields to provide steep focusing angles

  7. Fast-Particle-Driven Alfvenic Modes in a Reversed Field Pinch

    Energy Technology Data Exchange (ETDEWEB)

    Koliner, J. J. [University of Wisconsin, Madison; Forest, C. B. [University of Wisconsin, Madison; Sarff, J. S. [University of Wisconsin, Madison; Anderson, J. [University of Wisconsin, Madison; Liu, D [University of Wisconsin, Madison; Nomberg, M. D. [University of Wisconsin, Madison; Waksman, J. [University of Wisconsin, Madison; Lin, L. [University of California, Los Angeles; Brower, D. L. [University of California, Los Angeles; Ding, W. X. [University of California, Los Angeles; Spong, Donald A [ORNL

    2012-01-01

    Alfvenic modes are observed due to neutral beam injection for the first time in a reversed field pinch plasma. Modeling of the beam deposition and slowing down shows that the velocity and radial localization are high. This allows instability drive from inverse Landau damping of a bump-on-tail in the parallel distribution function or from free energy in the fast ion density gradient. Mode switching from a lower frequency toroidal mode number n = 5 mode that scales with beam injection velocity to a higher frequency n = 4 mode with Alfvenic scaling is observed.

  8. MCNPX simulations of fast neutron diagnostics for accelerator-driven systems

    Energy Technology Data Exchange (ETDEWEB)

    Habob, Moinul

    2005-12-15

    In accelerator-driven systems, the neutron spectrum will extend all the way up to the incident beam energy, i.e., several hundred MeV or even up to GeV energies. The high neutron energy allows novel diagnostics with a set of measurement techniques that can be used in a sub-critical reactor environment. Such measurements are primarily connected to system safety and validation. This report shows that in-core fast-neutron diagnostics can be employed to monitor changes in the position of incidence of the primary proton beam onto the neutron production target. It has also been shown that fast neutrons can be used to detect temperature-dependent density changes in a liquid lead-bismuth target. Fast neutrons can escape the system via the beam pipe for the incident proton beam. Out-of-core monitoring of these so called back-streaming neutrons could potentially be used to monitor beam changes if the target has a suitable shape. Moreover, diagnostics of back-streaming neutrons might be used for validation of the system design.

  9. Fast-ion dynamics in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Bindslev, H.; Nielsen, S.K.; Porte, L.;

    2006-01-01

    Here we present the first measurements by collective Thomson scattering of the evolution of fast-ion populations in a magnetically confined fusion plasma. 150 kW and 110 Ghz radiation from a gyrotron were scattered in the TEXTOR tokamak plasma with energetic ions generated by neutral beam injecti...

  10. Internal Transport Barrier Driven by Redistribution of Energetic Ions

    Energy Technology Data Exchange (ETDEWEB)

    K.L. Wong; W.W. Heidbrink; E. Ruskov; C.C. Petty; C.M. Greenfield; R. Nazikian; R. Budny

    2004-11-12

    Alfven instabilities excited by energetic ions are used as a means to reduce the central magnetic shear in a tokamak via redistribution of energetic ions. When the central magnetic shear is low enough, ballooning modes become stable for any plasma pressure gradient and an internal transport barrier (ITB) with a steep pressure gradient can exist. This mechanism can sustain a steady-state ITB as demonstrated by experimental data from the DIII-D tokamak. It can also produce a shear in toroidal and poloidal plasma rotation. Possible application of this technique to use the energetic alpha particles for improvement of burning plasma performance is discussed.

  11. Photoemission starting of induction rf-driven multicusp ion sources

    Science.gov (United States)

    Pickard, D. S.; Leung, K. N.; Perkins, L. T.; Ponce, D. M.; Young, A. T.

    1996-02-01

    It has been demonstrated that pulsed and continuous wave, rf-driven hydrogen discharges can be started with photoemission. The extracted H- current from a photoemission-started plasma has been investigated and does not differ significantly from that of a filament-started plasma. The minimum pressure for photoemissive starting was found to be higher than that of filament starting, 17 mTorr compared to 7 mTorr, respectively, in this particular configuration.

  12. Calculation of the ionization differential effective cross sections in fast ion-atom collisions

    CERN Document Server

    Kaminskij, A K

    2002-01-01

    The method of the calculations of the ionization effective cross sections d sigma/d OMEGA differential in the incident ion scattering angle is described in fast collisions of light ions and atoms. The calculated values of angular distributions of the ions Al, Mg (for the different values of charge and energy of ions) after their collisions with the Ne, Mg atoms being ionized are reported. The dependence of such angular distributions on the incident ion charge and energy and the initial state of ejected electron is investigated

  13. Dissociation of fast ions analyzed by time-of-flight

    Energy Technology Data Exchange (ETDEWEB)

    Ponciano, C.R.; Ladeia, R.C.C.; Collado, V.M.; Silveira, E.F. da [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Fisica]. E-mail: enio@vdg.fis.puc-rio.br

    2001-09-01

    The fragmentation of metastable ions, having keV of kinetic energy, is analyzed by time-of-flight technique. Assuming isotropic distribution of fragments in a free field region, it is deduced an analytical expression to describe the corresponding peak shapes in linear TOF spectrometers. Metastable ion mean-life and the kinetic energy release (Q-value) are the quantities extracted from data fitting. As an illustration, the dissociation of C{sub 8} H{sub 10} N{sup +} metastable ions, desorbed by {sup 252} Cf fission fragment impact on organic target, is studied. (author)

  14. Calibration techniques for fast-ion D{sub {alpha}} diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Heidbrink, W. W.; Bortolon, A.; Muscatello, C. M.; Ruskov, E. [University of California, Irvine, California 92697 (United States); Grierson, B. A.; Podesta, M. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2012-10-15

    Fast-ion D{sub {alpha}} measurements are an application of visible charge-exchange recombination (CER) spectroscopy that provide information about the energetic ion population. Like other CER diagnostics, the standard intensity calibration is obtained with an integrating sphere during a vacuum vessel opening. An alternative approach is to create plasmas where the fast-ion population is known, then calculate the expected signals with a synthetic diagnostic code. The two methods sometimes agree well but are discrepant in other cases. Different background subtraction techniques and simultaneous measurements of visible bremsstrahlung and of beam emission provide useful checks on the calibrations and calculations.

  15. Development towards a fast ion loss detector for the reversed field pinch

    Science.gov (United States)

    Bonofiglo, P. J.; Anderson, J. K.; Almagri, A. F.; Kim, J.; Clark, J.; Capecchi, W.; Sears, S. H.; Egedal, J.

    2016-11-01

    A fast ion loss detector has been constructed and implemented on the Madison Symmetric Torus (MST) to investigate energetic ion losses and transport due to energetic particle and MHD instabilities. The detector discriminates particle orbits solely on pitch and consists of two thin-foil, particle collecting plates that are symmetric with respect to the device aperture. One plate collects fast ion signal, while the second aids in the minimization of background and noise effects. Initial measurements are reported along with suggestions for the next design phase of the detector.

  16. Improved Collective Thomson Scattering measurements of fast ions at ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, J.; Nielsen, S. K.; Stejner, M.; Salewski, M.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K. [Association Euratom-DTU, Technical University of Denmark, Department of Physics, DTU Riso/ Campus, DK-4000 Roskilde (Denmark); Moseev, D. [Association Euratom-FOM Institute DIFFER, 3430 BE Nieuwegein (Netherlands); Schubert, M.; Stober, J.; Tardini, G.; Wagner, D.; Collaboration: ASDEX Upgrade Team

    2014-08-21

    Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based on the improved background characterization. These results have been obtained both with and without NBI heating, and with the measurement volume located close to the centre of the plasma. The measurements agree quantitatively with predictions of numerical simulations. Hence, CTS studies of fast-ion dynamics at ASDEX Upgrade are now feasible. The new background subtraction technique could be important for the design of CTS systems in other fusion experiments.

  17. Generation of fast highly charged ions in laser-plasma interaction

    Energy Technology Data Exchange (ETDEWEB)

    Wolowski, J [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Badziak, J [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Boody, F P [Ion Light Technologies GmbH, Bad Abbach (Germany); Czarnecka, A [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Gammino, S [INFN-Laboratori Nazionali del Sud, Catania (Italy); Jablonski, S [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Krasa, J [Institute of Physics, ASCR (Czech Republic); Laska, L [Institute of Physics, ASCR (Czech Republic); Parys, P [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Rohlena, K [Institute of Physics, ASCR (Czech Republic); Rosinski, M [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Ryc, L [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Torrisi, L [INFN-Laboratori Nazionali del Sud, Catania (Italy); Ullschmied, J [IPALS Research Centre ASCR, Prague (Czech Republic)

    2006-12-15

    The nonthermal and nonlinear coupling of strong laser light wave with plasma transfers a part of laser energy into hot electrons and fast ions. The efficiency of these effects depends on the characteristics of a laser pulse, target properties and irradiation geometry. The reported studies were performed with the use of a high-power and high-energy iodine PALS laser system (energy up to 1 kJ in a 0.4 ns pulse at wavelength of 1315 nm and energy up to 250 J at wavelength of 438 nm). The properties of the laser-produced ion streams were determined with the use of ion diagnostics based on the time-of-flight method. The characteristics of x-rays were measured using various semiconductor detectors. The main ion stream characteristics as well as the ion acceleration processes in plasmas of different Z numbers were studied in dependence on laser pulse parameters. The parameters of a fast ion group depend evidently on Z number of the ions. The influence of the electron density scale length on fast ion generation was investigated using a low intensity laser pre-pulses to generate preformed plasmas (pre-plasmas) with which the main laser pulse interacted. The obtained results suggest that ion acceleration processes were most effective at a specific electron density gradient scale length of pre-plasma determined by the pre-pulse parameters.

  18. Higher order Larmor radius corrections to guiding-centre equations and application to fast ion equilibrium distributions

    Science.gov (United States)

    Lanthaler, S.; Pfefferlé, D.; Graves, J. P.; Cooper, W. A.

    2017-04-01

    An improved set of guiding-centre equations, expanded to one order higher in Larmor radius than usually written for guiding-centre codes, are derived for curvilinear flux coordinates and implemented into the orbit following code VENUS-LEVIS. Aside from greatly improving the correspondence between guiding-centre and full particle trajectories, the most important effect of the additional Larmor radius corrections is to modify the definition of the guiding-centre’s parallel velocity via the so-called Baños drift. The correct treatment of the guiding-centre push-forward with the Baños term leads to an anisotropic shift in the phase-space distribution of guiding-centres, consistent with the well-known magnetization term. The consequence of these higher order terms are quantified in three cases where energetic ions are usually followed with standard guiding-centre equations: (1) neutral beam injection in a MAST-like low aspect-ratio spherical equilibrium where the fast ion driven current is significantly larger with respect to previous calculations, (2) fast ion losses due to resonant magnetic perturbations where a lower lost fraction and a better confinement is confirmed, (3) alpha particles in the ripple field of the European DEMO where the effect is found to be marginal.

  19. Creation and characterization of free-standing cryogenic targets for laser-driven ion acceleration

    Science.gov (United States)

    Tebartz, Alexandra; Bedacht, Stefan; Hesse, Markus; Astbury, Sam; Clarke, Rob; Ortner, Alex; Schaumann, Gabriel; Wagner, Florian; Neely, David; Roth, Markus

    2017-09-01

    A technique for the creation of free-standing cryogenic targets for laser-driven ion acceleration is presented, which allows us to create solid state targets consisting of initially gaseous materials. In particular, the use of deuterium and the methods for its preparation as a target material for laser-driven ion acceleration are discussed. Moving in the phase diagram through the liquid phase leads to the substance covering an aperture on a cooled copper frame where it is solidified through further cooling. An account of characterization techniques for target thickness is given, with a focus on deducing thickness values from distance values delivered by chromatic confocal sensors.

  20. Photoemission starting of induction rf-driven multicusp ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Pickard, D.S.; Leung, K.N.; Perkins, L.T.; Ponce, D.M.; Young, A.T. [Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)

    1996-02-01

    It has been demonstrated that pulsed and continuous wave, rf-driven hydrogen discharges can be started with photoemission. The extracted H{sup {minus}} current from a photoemission-started plasma has been investigated and does not differ significantly from that of a filament-started plasma. The minimum pressure for photoemissive starting was found to be higher than that of filament starting, 17 mTorr compared to 7 mTorr, respectively, in this particular configuration. {copyright} {ital 1996 American Institute of Physics.}

  1. rf driven multicusp H sup minus ion source

    Energy Technology Data Exchange (ETDEWEB)

    Leung, K.N.; DeVries, G.J.; DiVergilio, W.F.; Hamm, R.W.; Hauck, C.A.; Kunkel, W.B.; McDonald, D.S.; Williams, M.D. (Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (US))

    1991-01-01

    An rf driven multicusp source capable of generating 1-ms H{sup {minus}} beam pulses with a repetition rate as high as 150 Hz has been developed. This source can be operated with a filament or other types of starter. There is almost no lifetime limitation and a clean plasma can be maintained for a long period of operation. It is demonstrated that rf power as high as 25 kW could be coupled inductively to the plasma via a glass-coated copper-coil antenna. The extracted H{sup {minus}} current density achieved is about 200 mA/cm{sup 2}.

  2. Development of a Real-Time Ion Spectrometer with a Scintillator for Laser-Driven Ion Acceleration Experiments

    Institute of Scientific and Technical Information of China (English)

    XU Miao-Hua; David Neely; Paul McKenna; WANG Zhao-Hua; WEI Zhi-Yi; YAN Xue-Qing; LI Yu-Tong; LI Ying-Jun; ZHANG Jie; LI Hong-Wei; LIU Bi-Cheng; LIU Feng; SU Lu-Ning; DU Fei; ZHANG Lu; ZHENG Yi; MA Jing-Long

    2011-01-01

    A real-time ion spectrometer mainly based on a high-resolution Thomson parabola and a plastic scintillator is designed and developed. The spectrometer is calibrated by protons from an electrostatic accelerator. The feasibility and reliability of the diagnostics ore demonstrated in laser-driven ion acceleration experiments performed on the XL-H laser facility. The proton spectrum extrapolated from the scintillator data is in excellent agreement with the CR39 spectrum in terms of beam temperature and the cutoff energy. This real-time spectrometer allows an online measurement of the ion spectra in single shot, which enables efficient and statistical studies and applications in high-repetition-rate laser acceleration experiments.%@@ A real-time ion spectrometer mainly based on a high-resolution Thomson parabola and a plastic scintillator is designed and developed.The spectrometer is calibrated by protons from an electrostatic accelerator.The feasi-bility and reliability of the diagnostics are demonstrated in laser-driven ion acceleration experiments performed on the XL-Ⅱ laser facility.The proton spectrum extrapolated from the scintillator data is in excellent agreement with the CR39 spectrum in terms of beam temperature and the cutoff energy.This real-time spectrometer allows an online measurement of the ion spectra in single shot,which enables efficient and statistical studies and applications in high-repetition-rate laser acceleration experiments.

  3. Fast surrogate-assisted simulation-driven optimization of compact microwave hybrid couplers

    Science.gov (United States)

    Kurgan, Piotr; Koziel, Slawomir

    2016-07-01

    This work presents a robust methodology for expedited simulation-driven design optimization of compact microwave hybrid couplers. The technique relies on problem decomposition, and a bottom-up design strategy, starting from the level of basic building blocks of the coupler, and finishing with a tuning procedure that exploits a fast surrogate model of the entire structure. The latter is constructed by cascading local response surface approximations of coupler elementary elements. The cross-coupling effects within the structure are neglected in the first stage of the design process; however, they are accounted for in the tuning phase by means of space-mapping correction of the surrogate. The proposed approach is demonstrated through the design of a compact rat-race and two branch-line couplers. In all cases, the computational cost of the optimization process is very low and corresponds to just a few high-fidelity electromagnetic simulations of respective structures. Experimental validation is also provided.

  4. Research on ultra-fast vacuum mechanical switch driven by repulsive force actuator

    Science.gov (United States)

    Yuan, Zhao; He, Junjia; Pan, Yuan; Jing, Xin; Zhong, Canyi; Zhang, Ning; Wei, Xiaoguang; Tang, Guangfu

    2016-12-01

    In order to meet the fast operation demands of DC circuit breakers, a high-speed vacuum mechanical switch (VMS) driven by a repulsive force actuator is focused. To improve the drive speed and energy conversion efficiency (ECE) of the actuators, the dynamic characteristics of the double sided coil repulsive force actuators are investigated, and two generalized optimization design methods focusing on the aspect ratio of the driving coils (defined as ARF) and the electrical parameters (defined as EF) are developed. FEM simulation models' simulation and tests of VMS prototypes are conducted to verify the optimization methods. Results prove that the ARF method could improve the ECE of a VMS from 1.05% to 7.55%, and EF method could improve ECE of the same VMS from 1.05% to 6.61%, the combination of ARF and EF could improve the value of VMS's ECE to 10.50%, thus proving the validity and accuracy of the optimization methods.

  5. Guided post-acceleration of laser-driven ions by a miniature modular structure

    Science.gov (United States)

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L. S.; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P. L.; Schroer, Anna M.; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-04-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m-1, already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications.

  6. Laser-driven ion accelerators for tumor therapy revisited

    Science.gov (United States)

    Linz, Ute; Alonso, Jose

    2016-12-01

    Ten years ago, the authors of this report published a first paper on the technical challenges that laser accelerators need to overcome before they could be applied to tumor therapy. Among the major issues were the maximum energy of the accelerated ions and their intensity, control and reproducibility of the laser-pulse output, quality assurance and patient safety. These issues remain today. While theoretical progress has been made for designing transport systems, for tailoring the plumes of laser-generated protons, and for suitable dose delivery, today's best lasers are far from reaching performance levels, in both proton energy and intensity to seriously consider clinical ion beam therapy (IBT) application. This report details these points and substantiates that laser-based IBT is neither superior to IBT with conventional particle accelerators nor ready to replace it.

  7. A simple radionuclide-driven single-ion source

    CERN Document Server

    Díez, M Montero; Fairbank, W; Gratta, G; Barbeau, P S; Barry, K; DeVoe, R; Dolinski, M J; Green, M; LePort, F; Müller, A R; Neilson, R; O'Sullivan, K; Ackerman, N; Aharmin, B; Auger, M; Benitez-Medina, C; Breidenbach, M; Burenkov, A; Cook, S; Daniels, T; Donato, K; Farine, J; Giroux, G; Gornea, R; Graham, K; Hagemann, C; Hall, C; Hall, K; Hallman, D; Hargrove, C; Herrin, S; Karelin, A; Kaufman, L J; Kuchenkov, A; Kumar, K; Lacey, J; Leonard, D S; Mackay, D; MacLellan, R; Mong, B; Niner, E; Odian, A; Piepke, A; Pocar, A; Prescott, C Y; Pushkin, K; Rollin, E; Rowson, P C; Sinclair, D; Slutsky, S; Stekhanov, V; Vuilleumier, J -L; Wichoski, U; Wodin, J; Yang, L; Yen, Y -R

    2010-01-01

    We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating 148Gd onto a silicon {\\alpha}-particle detector and vapor depositing a layer of BaF2 over it. 144Sm recoils from the alpha decay of 148Gd are used to dislodge Ba+ ions from the BaF2 layer and emit them in the surrounding environment. The simultaneous detection of an {\\alpha} particle in the substrate detector allows for tagging of the nuclear decay and of the Ba+ emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.

  8. A simple radionuclide-driven single-ion source

    Energy Technology Data Exchange (ETDEWEB)

    Montero Diez, M.; Twelker, K.; Gratta, G.; Barbeau, P. S.; Barry, K.; DeVoe, R.; Dolinski, M. J.; Green, M.; LePort, F.; Mueller, A. R.; Neilson, R.; O' Sullivan, K. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Fairbank, W. Jr.; Benitez-Medina, C.; Cook, S.; Hall, K.; Mong, B. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States); Ackerman, N.; Breidenbach, M.; Herrin, S. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); and others

    2010-11-15

    We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating {sup 148}Gd onto a silicon {alpha}-particle detector and vapor depositing a layer of BaF{sub 2} over it. {sup 144}Sm recoils from the alpha decay of {sup 148}Gd are used to dislodge Ba{sup +} ions from the BaF{sub 2} layer and emit them in the surrounding environment. The simultaneous detection of an {alpha} particle in the substrate detector allows for tagging of the nuclear decay and of the Ba{sup +} emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.

  9. Efficient cesiation in RF driven surface plasma negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Belchenko, Yu.; Ivanov, A.; Konstantinov, S.; Sanin, A., E-mail: sanin@inp.nsk.su; Sotnikov, O. [Budker Institute of Nuclear Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2016-02-15

    Experiments on hydrogen negative ions production in the large radio-frequency negative ion source with cesium seed are described. The system of directed cesium deposition to the plasma grid periphery was used. The small cesium seed (∼0.5 G) provides an enhanced H{sup −} production during a 2 month long experimental cycle. The gradual increase of negative ion yield during the long-term source runs was observed after cesium addition to the source. The degraded H{sup −} production was recorded after air filling to the source or after the cesium washing away from the driver and plasma chamber walls. The following source conditioning by beam shots produces the gradual recovery of H{sup −} yield to the high value. The effect of H{sup −} yield recovery after cesium coverage passivation by air fill was studied. The concept of cesium coverage replenishment and of H{sup −} yield recovery due to sputtering of cesium from the deteriorated layers is discussed.

  10. Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.

    Science.gov (United States)

    Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M

    2015-03-27

    An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19}  W/  cm^{2}. Highly charged gold ions with kinetic energies up to >200  MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.

  11. Invited Review Article: "Hands-on" laser-driven ion acceleration: A primer for laser-driven source development and potential applications

    Science.gov (United States)

    Schreiber, J.; Bolton, P. R.; Parodi, K.

    2016-07-01

    An overview of progress and typical yields from intense laser-plasma acceleration of ions is presented. The evolution of laser-driven ion acceleration at relativistic intensities ushers prospects for improved functionality and diverse applications which can represent a varied assortment of ion beam requirements. This mandates the development of the integrated laser-driven ion accelerator system, the multiple components of which are described. Relevant high field laser-plasma science and design of controlled optimum pulsed laser irradiation on target are dominant single shot (pulse) considerations with aspects that are appropriate to the emerging petawatt era. The pulse energy scaling of maximum ion energies and typical differential spectra obtained over the past two decades provide guidance for continued advancement of laser-driven energetic ion sources and their meaningful applications.

  12. Invited Review Article: “Hands-on” laser-driven ion acceleration: A primer for laser-driven source development and potential applications

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, J. [Lehrstuhl für Medizinphysik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748 Garching bei München (Germany); Max-Planck-Institut für Quantenoptik Garching, Hans-Kopfermann-Str. 1, 85748 Garching bei München (Germany); Bolton, P. R.; Parodi, K. [Lehrstuhl für Medizinphysik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748 Garching bei München (Germany)

    2016-07-15

    An overview of progress and typical yields from intense laser-plasma acceleration of ions is presented. The evolution of laser-driven ion acceleration at relativistic intensities ushers prospects for improved functionality and diverse applications which can represent a varied assortment of ion beam requirements. This mandates the development of the integrated laser-driven ion accelerator system, the multiple components of which are described. Relevant high field laser-plasma science and design of controlled optimum pulsed laser irradiation on target are dominant single shot (pulse) considerations with aspects that are appropriate to the emerging petawatt era. The pulse energy scaling of maximum ion energies and typical differential spectra obtained over the past two decades provide guidance for continued advancement of laser-driven energetic ion sources and their meaningful applications.

  13. Radiation Hydrodynamic Simulations of Line-Driven Disk Winds for Ultra Fast Outflows

    CERN Document Server

    Nomura, Mariko; Takahashi, Hiroyuki R; Wada, Keiichi; Yoshida, Tessei

    2015-01-01

    Using two-dimensional radiation hydrodynamic simulations, we investigate origin of the ultra fast outflows (UFOs) that are often observed in luminous active galactic nuclei (AGNs). We found that the radiation force due to the spectral lines generates strong winds (line-driven disk winds) that are launched from the inner region of accretion disks (~30 Schwarzschild radii). A wide range of black hole masses ($M_{\\rm BH}$) and Eddington ratios ($\\varepsilon$) was investigated to study conditions for causing the line-driven winds. For $M_{\\rm BH} = 10^6-10^9 M_\\odot$ and $\\varepsilon = 0.1-0.7$, funnel-shaped disk winds appear, in which dense matter is accelerated outward with an opening angle of 70-80 deg and with 10% of the light speed. If we observe the wind along its direction, the velocity, the column density, and the ionization state are consistent with those of the observed UFOs. As long as the obscuration by the torus does not affect the observations of X-ray bands, the UFOs could be statistically observe...

  14. Nonlinear phenomenon in nanostructures creation by fast cluster ions

    Science.gov (United States)

    Moslem, W. M.; El-Said, A. S.; Sabry, R.; Shalouf, A.; El-Labany, S. K.; Bahlouli, H.

    2017-01-01

    The development of accelerators technology offers a new window for the creation of surface nanostructures in an efficient and accurate way. The use of 30 MeV C60 cluster ions enables the creation of nano-hillocks of size larger than the ones produced by GeV monoatomic ions. The physical mechanism underlying the realization of such nanostructures is elucidated using a plasma expansion approach. Numerical analysis showed that increasing the ionic temperature (number density) ratios would lead to decrease (increase) the nano-hillocks height.

  15. Nonlinear stabilization of tokamak microturbulence by fast ions

    CERN Document Server

    Citrin, J; Garcia, J; Haverkort, J W; Hogeweij, G M D; Jenko, F; Johnson, T; Mantica, P; Pueschel, M J; Told, D; contributors, JET-EFDA

    2013-01-01

    Nonlinear electromagnetic stabilization by suprathermal pressure gradients found in specific regimes is shown to be a key factor in reducing tokamak microturbulence, augmenting significantly the thermal pressure electromagnetic stabilization. Based on nonlinear gyrokinetic simulations investigating a set of ion heat transport experiments on the JET tokamak, described by Mantica et al. [Phys. Rev. Lett. 107 135004 (2011)], this result explains the experimentally observed ion heat flux and stiffness reduction. These findings are expected to improve the extrapolation of advanced tokamak scenarios to reactor relevant regimes.

  16. Fasting-Mimicking Diet Promotes Ngn3-Driven β-Cell Regeneration to Reverse Diabetes.

    Science.gov (United States)

    Cheng, Chia-Wei; Villani, Valentina; Buono, Roberta; Wei, Min; Kumar, Sanjeev; Yilmaz, Omer H; Cohen, Pinchas; Sneddon, Julie B; Perin, Laura; Longo, Valter D

    2017-02-23

    Stem-cell-based therapies can potentially reverse organ dysfunction and diseases, but the removal of impaired tissue and activation of a program leading to organ regeneration pose major challenges. In mice, a 4-day fasting mimicking diet (FMD) induces a stepwise expression of Sox17 and Pdx-1, followed by Ngn3-driven generation of insulin-producing β cells, resembling that observed during pancreatic development. FMD cycles restore insulin secretion and glucose homeostasis in both type 2 and type 1 diabetes mouse models. In human type 1 diabetes pancreatic islets, fasting conditions reduce PKA and mTOR activity and induce Sox2 and Ngn3 expression and insulin production. The effects of the FMD are reversed by IGF-1 treatment and recapitulated by PKA and mTOR inhibition. These results indicate that a FMD promotes the reprogramming of pancreatic cells to restore insulin generation in islets from T1D patients and reverse both T1D and T2D phenotypes in mouse models. PAPERCLIP.

  17. Multi-view fast-ion D-alpha spectroscopy diagnostic at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, B.; Dux, R.; McDermott, R. M.; Potzel, S.; Reich, M.; Ryter, F.; Weiland, M.; Wünderlich, D. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Garcia-Munoz, M. [Faculty of Physics, University of Seville, Seville (Spain); Collaboration: ASDEX Upgrade Team

    2013-11-15

    A novel fast-ion D-alpha (FIDA) diagnostic that is based on charge exchange spectroscopy has been installed at ASDEX Upgrade. The diagnostic uses a newly developed high-photon-throughput spectrometer together with a low-noise EM-CCD camera that allow measurements with 2 ms exposure time. Absolute intensities are obtained by calibrating the system with an integrating sphere and the wavelength dependence is determined to high accuracy using a neon lamp. Additional perturbative contributions to the spectra, such as D{sub 2}-molecular lines, the Stark broadened edge D-alpha emission, and passive FIDA radiation have been identified and can be subtracted or avoided experimentally. The FIDA radiation from fast deuterium ions after charge exchange reactions can therefore be analyzed continuously without superimposed line emissions at large Doppler shifts. Radial information on the fast ions is obtained from radially distributed lines of sight. The investigation of the fast-ion velocity distribution is possible due to three different viewing geometries. The independent viewing geometries access distinct parts of the fast-ion velocity space and make tomographic reconstructions possible.

  18. Action-angle formulation of generalized, orbit-based, fast-ion diagnostic weight functions

    Science.gov (United States)

    Stagner, L.; Heidbrink, W. W.

    2017-09-01

    Due to the usually complicated and anisotropic nature of the fast-ion distribution function, diagnostic velocity-space weight functions, which indicate the sensitivity of a diagnostic to different fast-ion velocities, are used to facilitate the analysis of experimental data. Additionally, when velocity-space weight functions are discretized, a linear equation relating the fast-ion density and the expected diagnostic signal is formed. In a technique known as velocity-space tomography, many measurements can be combined to create an ill-conditioned system of linear equations that can be solved using various computational methods. However, when velocity-space weight functions (which by definition ignore spatial dependencies) are used, velocity-space tomography is restricted, both by the accuracy of its forward model and also by the availability of spatially overlapping diagnostic measurements. In this work, we extend velocity-space weight functions to a full 6D generalized coordinate system and then show how to reduce them to a 3D orbit-space without loss of generality using an action-angle formulation. Furthermore, we show how diagnostic orbit-weight functions can be used to infer the full fast-ion distribution function, i.e., orbit tomography. In depth derivations of orbit weight functions for the neutron, neutral particle analyzer, and fast-ion D-α diagnostics are also shown.

  19. Fast ion mass spectrometry and charged particle spectrography investigations of transverse ion acceleration and beam-plasma interactions

    Science.gov (United States)

    Gibson, W. C.; Tomlinson, W. M.; Marshall, J. A.

    1987-01-01

    Ion acceleration transverse to the magnetic field in the topside ionosphere was investigated. Transverse acceleration is believed to be responsible for the upward-moving conical ion distributions commonly observed along auroral field lines at altitudes from several hundred to several thousand kilometers. Of primary concern in this investigation is the extent of these conic events in space and time. Theoretical predictions indicate very rapid initial heating rates, depending on the ion species. These same theories predict that the events will occur within a narrow vertical region of only a few hundred kilometers. Thus an instrument with very high spatial and temporal resolution was required; further, since different heating rates were predicted for different ions, it was necessary to obtain composition as well as velocity space distributions. The fast ion mass spectrometer (FIMS) was designed to meet these criteria. This instrument and its operation is discussed.

  20. The description of charge transfer in fast negative ions scattering on water covered Si(100) surfaces

    Science.gov (United States)

    Chen, Lin; Qiu, Shunli; Liu, Pinyang; Xiong, Feifei; Lu, Jianjie; Liu, Yuefeng; Li, Guopeng; Liu, Yiran; Ren, Fei; Xiao, Yunqing; Gao, Lei; Zhao, Qiushuang; Ding, Bin; Li, Yuan; Guo, Yanling; Chen, Ximeng

    2016-11-01

    Doping has significantly affected the characteristics and performance of semiconductor electronic devices. In this work, we study the charge transfer processes for 8.5-22.5 keV C- and F- ions scattering on H2O-terminated p-type Si(100) surfaces with two different doping concentrations. We find that doping has no influence on negative-ion formation for fast collisions in this relatively high energy range. Moreover, we build a model to calculate negative ion fractions including the contribution from positive ions. The calculations support the nonadiabatic feature of charge transfer.

  1. Shot-to-shot reproducibility in the emission of fast highly charged metal ions from a laser ion source.

    Science.gov (United States)

    Krása, J; Velyhan, A; Margarone, D; Krouský, E; Krouský, L; Jungwirth, K; Rohlena, K; Ullschmied, J; Parys, P; Ryć, L; Wołowski, J

    2012-02-01

    The generation of fast highly charged metal ions with the use of the sub-nanosecond Prague Asterix Laser System, operated at a fundamental wavelength of 1315 nm, is reported. Particular attention is paid to shot-to-shot reproducibility in the ion emission. Au and Pd targets were exposed to intensities up to 5 × 10(16) W∕cm(2). Above the laser intensity threshold of ∼3 × 10(14) W∕cm(2) the plasma is generated in a form of irregular bursts. The maximum energy of protons constituting the leading edge of the fastest burst reaches a value up to 1 MeV. The fast ions in the following bursts have energy gradually decreasing with the increasing burst number, namely, from a value of about 0.5 MeV∕charge regardless of the atomic number and mass of the ionized species.

  2. Ion temperature gradient driven mode in presence of transverse velocity shear in magnetized plasmas

    DEFF Research Database (Denmark)

    Chakrabarti, N.; Juul Rasmussen, J.; Michelsen, Poul

    2005-01-01

    The effect of sheared poloidal flow on the toroidal branch of the ion temperature gradient driven mode of magnetized nonuniform plasma is studied. A novel "nonmodal" calculation is used to analyze the problem. It is shown that the transverse shear flow considerably reduced the growth...

  3. Optimization of negative ion current in a compact microwave driven upper hybrid resonance multicusp plasma source.

    Science.gov (United States)

    Sahu, D; Bhattacharjee, S; Singh, M J; Bandyopadhyay, M; Chakraborty, A

    2012-02-01

    Performance of a microwave driven upper hybrid resonance multicusp plasma source as a volume negative ion source is reported. Microwaves are directly launched into the plasma chamber predominantly in the TE(11) mode. The source is operated at different discharge conditions to obtain the optimized negative H(-) ion current which is ∼33 μA (0.26 mA∕cm(2)). Particle balance equations are solved to estimate the negative ion density, which is compared with the experimental results. Future prospects of the source are discussed.

  4. Optimization of negative ion current in a compact microwave driven upper hybrid resonance multicusp plasma sourcea)

    Science.gov (United States)

    Sahu, D.; Bhattacharjee, S.; Singh, M. J.; Bandyopadhyay, M.; Chakraborty, A.

    2012-02-01

    Performance of a microwave driven upper hybrid resonance multicusp plasma source as a volume negative ion source is reported. Microwaves are directly launched into the plasma chamber predominantly in the TE11 mode. The source is operated at different discharge conditions to obtain the optimized negative H- ion current which is ˜33 μA (0.26 mA/cm2). Particle balance equations are solved to estimate the negative ion density, which is compared with the experimental results. Future prospects of the source are discussed.

  5. Resistance-driven bunching mode of an accelerated ion pulse

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E.P.

    1981-10-16

    Amplification of a longitudinal perturbation of an ion pulse in a linear induction accelerator is calculated. The simplified accelerator model consists only of an applied field (E/sub a/), distributed gap impedance per meter (R) and beam-pipe capacity per meter (C). The beam is treated as a cold, one-dimensional fluid. It is found that normal mode frequencies are nearly real, with only a very small damping rate proportional to R. This result is valid for a general current profile and is not restricted to small R. However, the mode structure exhibits spatial amplification from pulse head to tail by the factor exp(RCLv/sub o//2), where L is pulse length and v/sub 0/ is drift velocity. This factor is very large for typical HIF parameters. An initially small disturbance, when expanded in terms of the normal modes, is found to oscillate with maximum amplitude proportional to the amplification factor.

  6. Effect of Energetic-Ion-Driven MHD Instabilities on Energetic-Ion-Transport in Compact Helical System and Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Isobe, M. [National Institute for Fusion Science, Toki, Japan; Ogawa, K. [Nagoya University, Japan; Toi, K. [National Institute for Fusion Science, Toki, Japan; Osakabe, M. [National Institute for Fusion Science, Toki, Japan; Nagaoka, K. [National Institute for Fusion Science, Toki, Japan; Shimizu, A. [National Institute for Fusion Science, Toki, Japan; Spong, Donald A [ORNL; Okumura, S. [National Institute for Fusion Science, Toki, Japan

    2010-01-01

    This paper describes 1) representative results on excitation of energetic-particle mode (EPM) and toroidicity-induced Alfven eigenmode (TAE) and consequent beam-ion losses in CHS, and 2) recent results on beam-ion transport and/or losses while EPMs are destabilized in LHD. Bursting EPMs and TAEs are often excited by co-injected beam ions in the high-beam ion pressure environment and give a significant effect on co-going beam ions in both experiments. It seems that in CHS, resonant beam ions are lost within a relatively short-time scale once they are anomalously transported due to energetic-ion driven MHD modes, whereas unlike CHS, redistribution of beam ions due to energetic-ion driven MHD modes is seen in LHD, suggesting that not all anomalously transported beam ions escape from the plasma.

  7. Effect of energetic-ion-driven MHD instabilities on energetic-ion-transport in compact helical system and large helical device

    Energy Technology Data Exchange (ETDEWEB)

    Isobe, M.; Toi, K.; Osakabe, M.; Nagaoka, K.; Shimizu, A.; Okamura, S. [National Institute for Fusion Science, Toki (Japan); Ogawa, K. [Department of Energy Science and Engineering, Nagoya University, Nagoya (Japan); Spong, D.A. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2010-08-15

    This paper describes (1) representative results on excitation of energetic-particle mode (EPM) and toroidicity-induced Alfven eigenmode (TAE) and consequent beam-ion losses in CHS, and (2) recent results on beam-ion transport and/or losses while EPMs are destabilized in LHD. Bursting EPMs and TAEs are often excited by co-injected beam ions in the high-beam ion pressure environment and give a significant effect on co-going beam ions in both experiments. It seems that in CHS, resonant beam ions are lost within a relatively short-time scale once they are anomalously transported due to energetic-ion driven MHD modes, whereas unlike CHS, redistribution of beam ions due to energetic-ion driven MHD modes is seen in LHD, suggesting that not all anomalously transported beam ions escape from the plasma. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Haseroth, Helmut [European Organization for Nuclear Research, Geneva (Switzerland); Hora, Heinrich [New South Wales Univ., Kensington, NSW (Australia)]|[Regensburg Inst. of Tech. (Germany). Anwenderzentrum

    1996-12-31

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10{sup 11} C{sup 4+} ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ``hot`` electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author).

  9. High-definition velocity-space tomography of fast-ion dynamics

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Jacobsen, A.S.

    2016-01-01

    Velocity-space tomography of the fast-ion distribution function in a fusion plasma is usually a photon-starved tomography method due to limited optical access and signal-to-noise ratio of fast-ion Dα (FIDA) spectroscopy as well as the strive for high-resolution images. In high-definition tomography......, prior information makes up for this lack of data. We restrict the target velocity space through the measured absence of FIDA light, impose phase-space densities to be non-negative, and encode the known geometry of neutral beam injection (NBI) sources. We further use a numerical simulation as prior...... information to reconstruct where in velocity space the measurements and the simulation disagree. This alternative approach is demonstrated for four-view as well as for two-view FIDA measurements. The high-definition tomography tools allow us to study fast ions in sawtoothing plasmas and the formation of NBI...

  10. Reduced Fast Ion Transport Model For The Tokamak Transport Code TRANSP

    Energy Technology Data Exchange (ETDEWEB)

    Podesta,, Mario; Gorelenkova, Marina; White, Roscoe

    2014-02-28

    Fast ion transport models presently implemented in the tokamak transport code TRANSP [R. J. Hawryluk, in Physics of Plasmas Close to Thermonuclear Conditions, CEC Brussels, 1 , 19 (1980)] are not capturing important aspects of the physics associated with resonant transport caused by instabilities such as Toroidal Alfv en Eigenmodes (TAEs). This work describes the implementation of a fast ion transport model consistent with the basic mechanisms of resonant mode-particle interaction. The model is formulated in terms of a probability distribution function for the particle's steps in phase space, which is consistent with the MonteCarlo approach used in TRANSP. The proposed model is based on the analysis of fast ion response to TAE modes through the ORBIT code [R. B. White et al., Phys. Fluids 27 , 2455 (1984)], but it can be generalized to higher frequency modes (e.g. Compressional and Global Alfv en Eigenmodes) and to other numerical codes or theories.

  11. Stability properties and fast ion confinement of hybrid tokamak plasma configurations

    Science.gov (United States)

    Graves, J. P.; Brunetti, D.; Pfefferle, D.; Faustin, J. M. P.; Cooper, W. A.; Kleiner, A.; Lanthaler, S.; Patten, H. W.; Raghunathan, M.

    2015-11-01

    In hybrid scenarios with flat q just above unity, extremely fast growing tearing modes are born from toroidal sidebands of the near resonant ideal internal kink mode. New scalings of the growth rate with the magnetic Reynolds number arise from two fluid effects and sheared toroidal flow. Non-linear saturated 1/1 dominant modes obtained from initial value stability calculation agree with the amplitude of the 1/1 component of a 3D VMEC equilibrium calculation. Viable and realistic equilibrium representation of such internal kink modes allow fast ion studies to be accurately established. Calculations of MAST neutral beam ion distributions using the VENUS-LEVIS code show very good agreement of observed impaired core fast ion confinement when long lived modes occur. The 3D ICRH code SCENIC also enables the establishment of minority RF distributions in hybrid plasmas susceptible to saturated near resonant internal kink modes.

  12. Modelling and simulation of surface morphology driven by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Yewande, E.O.

    2006-05-02

    Non-equilibrium surfaces, at nanometer length scales, externally driven via bombardment with energetic particles are known to exhibit well ordered patterns with a variety of applications in nano-technology. These patterns emerge at time scales on the order of minutes. Continuum theory has been quite successful in giving a general picture of the processes that interplay to give the observed patterns, as well as how such competition might determine the properties of the nanostructures. However, continuum theoretical descriptions are ideal only in the asymptotic limit. The only other theoretical alternative, which happens to be more suitable for the characteristic length-and time-scales of pattern formation, is Monte Carlo simulation. In this thesis, surface morphology is studied using discrete solid-on-solid Monte Carlo models of sputtering and surface diffusion. The simulations are performed in the context of the continuum theories and experiments. In agreement with the experiments, the ripples coarsen with time and the ripple velocity exhibits a power-law behaviour with the ripple wavelength, in addition, the exponent was found to depend on the simulation temperature, which suggests future experimental studies of flux dependence. Moreover, a detailed exploration of possible topographies, for different sputtering conditions, corresponding to different materials, was performed. And different surface topographies e.g. holes, ripples, and dots, were found at oblique incidence, without sample rotation. With sample rotation no new topography was found, its only role being to destroy any inherent anisotropy in the system. (orig.)

  13. Ion spectrometer composed of time-of-flight and Thomson parabola spectrometers for simultaneous characterization of laser-driven ions.

    Science.gov (United States)

    Choi, I W; Kim, C M; Sung, J H; Yu, T J; Lee, S K; Kim, I J; Jin, Y-Y; Jeong, T M; Hafz, N; Pae, K H; Noh, Y-C; Ko, D-K; Yogo, A; Pirozhkov, A S; Ogura, K; Orimo, S; Sagisaka, A; Nishiuchi, M; Daito, I; Oishi, Y; Iwashita, Y; Nakamura, S; Nemoto, K; Noda, A; Daido, H; Lee, J

    2009-05-01

    An ion spectrometer, composed of a time-of-flight spectrometer (TOFS) and a Thomson parabola spectrometer (TPS), has been developed to measure energy spectra and to analyze species of laser-driven ions. Two spectrometers can be operated simultaneously, thereby facilitate to compare the independently measured data and to combine advantages of each spectrometer. Real-time and shot-to-shot characterizations have been possible with the TOFS, and species of ions can be analyzed with the TPS. The two spectrometers show very good agreement of maximum proton energy even for a single laser shot. The composite ion spectrometer can provide two complementary spectra measured by TOFS with a large solid angle and TPS with a small one for the same ion source, which are useful to estimate precise total ion number and to investigate fine structure of energy spectrum at high energy depending on the detection position and solid angle. Advantage and comparison to other online measurement system, such as the TPS equipped with microchannel plate, are discussed in terms of overlay of ion species, high-repetition rate operation, detection solid angle, and detector characteristics of imaging plate.

  14. Geodesic mode instability driven by electron and ion fluxes in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Elfimov, A. G., E-mail: elfimov@if.usp.br; Camilo de Souza, F.; Galvão, R. M. O. [Institute of Physics, University of São Paulo, São Paulo 05508-090 (Brazil)

    2015-11-15

    The effect of the parallel electron current and plasma flux on Geodesic Acoustic Modes (GAM) in a tokamak is analyzed by kinetic theory taking into the account the ion Landau damping and diamagnetic drifts. It is shown that the electron current and plasma flow, modeled by shifted Maxwell distributions of electrons and ions, may overcome the ion Landau damping generating the GAM instability when the parallel electron current velocity is larger than the effective parallel GAM phase velocity of sidebands, Rqω. The instability is driven by the electron current and the parallel ion flux cross term. Possible applications to tokamak experiments are discussed. The existence of the geodesic ion sound mode due to plasma flow is shown.

  15. Influence of radiation reaction force on ultraintense laser-driven ion acceleration.

    Science.gov (United States)

    Capdessus, R; McKenna, P

    2015-05-01

    The role of the radiation reaction force in ultraintense laser-driven ion acceleration is investigated. For laser intensities ∼10(23)W/cm(2), the action of this force on electrons is demonstrated in relativistic particle-in-cell simulations to significantly enhance the energy transfer to ions in relativistically transparent targets, but strongly reduce the ion energy in dense plasma targets. An expression is derived for the revised piston velocity, and hence ion energy, taking account of energy loses to synchrotron radiation generated by electrons accelerated in the laser field. Ion mass is demonstrated to be important by comparing results obtained with proton and deuteron plasma. The results can be verified in experiments with cryogenic hydrogen and deuterium targets.

  16. Comparison of fast ion confinement during on-axis and off-axis neutral beam experiments on NSTX-U

    Science.gov (United States)

    Liu, D.; Heidbrink, W. W.; Hao, G. Z.; Podesta, M.; Darrow, D. S.; Fredrickson, E. D.; Medley, S. S.

    2015-11-01

    A second and more tangential neutral beam line is a major upgrade component of the National Spherical Torus Experiment - Upgrade (NSTX-U) with the purpose of improving neutral beam current drive efficiency and providing more flexibility in current/pressure profile control. Good fast ion confinement is essential to achieve the anticipated improvements in performance. In a planed ``sanity check'' experiment, various short and long (relative to fast ion slowing-down time) neutral beam (NB) pulses with different source mixes will be injected into quiescent L-mode plasmas to characterize the fast ion confinement and distribution function produced by the new and the existing NBI lines. The neutron rate decay after the turn-off of short NB pulses will be used to estimate the fast ion confinement time and to investigate its dependence on NB source/geometry, injection energy, and plasma current. The newly installed Solid State Neutral Particle Analyzer (SSNPA) and Fast-Ion D-Alapha (FIDA) diagnostics will be described and will be used to measure fast ion slowing-down distribution function and spatial profile during the injection of relatively long NB pulses. Fast ion prompt losses will be monitored with a scintillator Fast Lost Ion Probe (sFLIP) diagnostic. The experimental techniques, measurements of fast ion confinement time and distribution function, and comparisons with classical predictions from NUBEAM modeling will be presented in detail. Work supported by US DOE.

  17. Electroless Formation of Hybrid Lithium Anodes for Fast Interfacial Ion Transport.

    Science.gov (United States)

    Choudhury, Snehashis; Tu, Zhengyuan; Stalin, Sanjuna; Vu, Dylan; Fawole, Kristen; Gunceler, Deniz; Sundararaman, Ravishankar; Archer, Lynden

    2017-08-17

    Rechargeable batteries based on metallic anodes are of interest for fundamental and applications-focused studies of chemical and physical kinetics of liquids at solid interfaces. Approaches that allow facile creation of uniform coatings on these metals to prevent physical contact with liquid electrolytes, while enabling fast ion-transport, are essential to address chemical instability of the anodes. Here, we report a simple electroless ion-exchange chemistry for creating coatings of the metal Indium on lithium. By means of Joint-Density Functional theory and interfacial characterization experiments, we show that In coatings stabilize Li by multiple processes, including enabling exceptionally fast surface diffusion of lithium ions and high chemical resistance to liquid electrolytes. Indium coatings also undergo reversible alloying reactions with lithium ions, facilitating design of high-capacity hybrid In-Li anodes that utilize both alloying and plating chemistries for charge storage. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Improved Collective Thomson Scattering measurements of fast ions at ASDEX Upgrade

    CERN Document Server

    Rasmussen, J; Stejner, M; Salewski, M; Jacobsen, A S; Korsholm, S B; Leipold, F; Meo, F; Michelsen, P K; Moseev, D; Schubert, M; Stober, J; Tardini, G; Wagner, D

    2013-01-01

    Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based on the improved background characterization. These results have been obtained both with and without NBI heating, and with the measurem...

  19. Theory of ion transport with fast acid-base equilibrations in bioelectrochemical systems

    Science.gov (United States)

    Dykstra, J. E.; Biesheuvel, P. M.; Bruning, H.; Ter Heijne, A.

    2014-07-01

    Bioelectrochemical systems recover valuable components and energy in the form of hydrogen or electricity from aqueous organic streams. We derive a one-dimensional steady-state model for ion transport in a bioelectrochemical system, with the ions subject to diffusional and electrical forces. Since most of the ionic species can undergo acid-base reactions, ion transport is combined in our model with infinitely fast ion acid-base equilibrations. The model describes the current-induced ammonia evaporation and recovery at the cathode side of a bioelectrochemical system that runs on an organic stream containing ammonium ions. We identify that the rate of ammonia evaporation depends not only on the current but also on the flow rate of gas in the cathode chamber, the diffusion of ammonia from the cathode back into the anode chamber, through the ion exchange membrane placed in between, and the membrane charge density.

  20. Dynamics of a reconnection-driven runaway ion tail in a reversed field pinch plasma

    Science.gov (United States)

    Anderson, J. K.; Kim, J.; Bonofiglo, P. J.; Capecchi, W.; Eilerman, S.; Nornberg, M. D.; Sarff, J. S.; Sears, S. H.

    2016-05-01

    While reconnection-driven ion heating is common in laboratory and astrophysical plasmas, the underlying mechanisms for converting magnetic to kinetic energy remain not fully understood. Reversed field pinch discharges are often characterized by rapid ion heating during impulsive reconnection, generating an ion distribution with an enhanced bulk temperature, mainly perpendicular to magnetic field. In the Madison Symmetric Torus, a subset of discharges with the strongest reconnection events develop a very anisotropic, high energy tail parallel to magnetic field in addition to bulk perpendicular heating, which produces a fusion neutron flux orders of magnitude higher than that expected from a Maxwellian distribution. Here, we demonstrate that two factors in addition to a perpendicular bulk heating mechanism must be considered to explain this distribution. First, ion runaway can occur in the strong parallel-to-B electric field induced by a rapid equilibrium change triggered by reconnection-based relaxation; this effect is particularly strong on perpendicularly heated ions which experience a reduced frictional drag relative to bulk ions. Second, the confinement of ions varies dramatically as a function of velocity. Whereas thermal ions are governed by stochastic diffusion along tearing-altered field lines (and radial diffusion increases with parallel speed), sufficiently energetic ions are well confined, only weakly affected by a stochastic magnetic field. High energy ions traveling mainly in the direction of toroidal plasma current are nearly classically confined, while counter-propagating ions experience an intermediate confinement, greater than that of thermal ions but significantly less than classical expectations. The details of ion confinement tend to reinforce the asymmetric drive of the parallel electric field, resulting in a very asymmetric, anisotropic distribution.

  1. Fast cooling of trapped ions using the dynamical Stark shift gate

    OpenAIRE

    Retzker, A.; Plenio, M. B.

    2006-01-01

    A laser cooling scheme for trapped ions is presented which is based on the fast dynamical Stark shift gate, described in [Jonathan etal, PRA 62, 042307]. Since this cooling method does not contain an off resonant carrier transition, low final temperatures are achieved even in traveling wave light field. The proposed method may operate in either pulsed or continuous mode and is also suitable for ion traps using microwave addressing in strong magnetic field gradients.

  2. Gyro-Kinetic Electron and Fully-Kinetic Ion Simulations of Fast Magnetosonic Waves in the Magnetosphere

    Science.gov (United States)

    Gao, X.; Liu, K.; Wang, X.; Min, K.; Lin, Y.

    2016-12-01

    Two-dimensional simulations using a gyro-kinetic electron and fully-kinetic ion (GeFi) scheme are preformed to study the excitation of fast magnetosonic waves in the magnetosphere, which arise from the ion Bernstein instability driven by ring-like proton velocity distributions (with a positive slope with respect to the perpendicular velocity). Since both ion and electron kinetics are relevant, particle-in-cell (PIC) simulations have often been employed to study the wave excitation. However, such simulations are limited to reduced ion-to-electron mass ratio (mi/me) and light-to-Alfvén speed ratio (c/VA) due to the computationally expensive nature of PIC codes. The present study exploits a GeFi scheme that can break through these limitations and use larger/more realistic mi/me and c/VA. The capability of the GeFi code in simulating the ion Bernstein instability is first demonstrated by comparing a GeFi simulation using reduced mass ratio (mi/me=100) and speed ratio (c/VA=15) to a corresponding PIC simulation. A realistic speed ratio (c/VA=400) and a larger mass ratio (mi/me=400) are then adopted in the GeFi code to explore how the results vary. It is shown that the increased mi/me and c/VA lead to a larger lower hybrid frequency and allow waves to arise at more ion cyclotron harmonics, consistent with the general prediction of linear dispersion theory.

  3. Investigation of fast-ion generation in a laser plasma according to X-ray line radiation

    Science.gov (United States)

    Basov, N. G.; Maksimchuk, A. M.; Mikhailov, Iu. A.; Rode, A. V.; Getz, K.

    1987-04-01

    The profile of the 1s2-1s2p resonance line of the P XIV phosphorous ion is studied in order to derive the energy spectrum and indicatrix of fast ions in a laser plasma. The energetic and angular characteristics of fast ions are examined. The spectrum and indicatrix are analyzed using a model in which it is assumed that the ions are accelerated as a result of the self-focusing of laser radiation in the plasma corona.

  4. Dense blocks of energetic ions driven by multi-petawatt lasers

    CERN Document Server

    Weng, S M; Sheng, Z M; Murakami, M; Chen, M; Yu, L L; Zhang, J

    2016-01-01

    Laser-driven ion accelerators have the advantages of compact size, high density, and short bunch duration over conventional accelerators. Nevertheless, it is still challenging to simultaneously enhance the yield and quality of laser-driven ion beams for practical applications. Here we propose a scheme to address this challenge via the use of emerging multi-petawatt lasers and a density-modulated target. The density-modulated target permits its ions to be uniformly accelerated as a dense block by laser radiation pressure. In addition, the beam quality of the accelerated ions is remarkably improved by embedding the target in a thick enough substrate, which suppresses hot electron refluxing and thus alleviates plasma heating. Particle-in-cell simulations demonstrate that almost all ions in a solid-density plasma of a few microns can be uniformly accelerated to about 25% of the speed of light by a laser pulse at an intensity around 1022 W/cm2. The resulting dense block of energetic ions may drive fusion ignition ...

  5. On Properties of Compressional Alfven Eigenmode Instability Driven by Superalfvinic Ions

    Energy Technology Data Exchange (ETDEWEB)

    N.N. Gorelenkov; C.Z. Cheng

    2002-02-06

    Properties of the instability of Compressional Alfven Eigenmodes (CAE) in tokamak plasmas are studied in the cold plasma approximation with an emphasis on the instability driven by the energetic minority Ion Cyclotron Resonance Heating (ICRH) ions. We apply earlier developed theory [N.N. Gorelenkov and C.Z. Cheng, Nuclear Fusion 35 (1995) 1743] to compare two cases: Ion Cyclotron Emission (ICE) driven by charged fusion products and ICRH Minority driven ICE (MICE) [J. Cottrell, Phys. Rev. Lett. (2000)] recently observed on JET [Joint European Torus]. Particularly in MICE spectrum, only instabilities with even harmonics of deuterium-cyclotron frequency at the low-field-side plasma edge were reported. Odd deuterium-cyclotron frequency harmonics of ICE spectrum between the cyclotron harmonics of protons can be driven only via the Doppler-shifted cyclotron wave-particle resonance of CAEs with fusion products, but are shown to be damped due to the electron Landau damping in experiments on MI CE. Excitation of odd harmonics of MICE with high-field-side heating is predicted. Dependencies of the instability on the electron temperature is studied and is shown to be strong. Low electron temperature is required to excite odd harmonics in MICE.

  6. First measurements of Dα spectrum produced by anisotropic fast ions in the gas dynamic trap

    Science.gov (United States)

    Lizunov, A.; Anikeev, A.

    2014-11-01

    Angled injection of eight deuterium beams in gas dynamic trap (GDT) plasmas builds up the population of fast ions with the distribution function, which conserves a high degree of initial anisotropy in space, energy, and pitch angle. Unlike the Maxwellian distribution case, the fast ion plasma component in GDT cannot be exhaustively characterized by the temperature and density. The instrumentation complex to study of fast ions is comprised of motional Stark effect diagnostic, analyzers of charge exchange atoms, and others. The set of numerical codes using for equilibrium modeling is also an important tool of analysis. In the recent campaign of summer 2014, we recorded first signals from the new fast ion D-alpha diagnostic on GDT. This paper presents the diagnostic description and results of pilot measurements. The diagnostic has four lines of sight, distributed across the radius of an axially symmetric plasma column in GDT. In the present setup, a line-integrated optical signal is measured in each channel. In the transverse direction, the spatial resolution is 18 mm. Collected light comes to the grating spectrometer with the low-noise detector based on a charge-coupled device matrix. In the regime of four spectra stacked vertically on the sensor, the effective spectral resolution of measurements is approximately 0.015 nm. Exposure timing is provided by the fast optical ferroelectric crystal shutter, allowing frames of duration down to 70 μs. This number represents the time resolution of measurements. A large dynamic range of the camera permits for a measurement of relatively small light signals produced by fast ions on top of the bright background emission from the bulk plasma. The fast ion emission has a non-Gaussian spectrum featuring the characteristic width of approximately 4 nm, which can be separated from relatively narrow Gaussian lines of D-alpha and H-alpha coming from the plasma periphery, and diagnostic beam emission. The signal to noise ratio varies

  7. Properties of the Fast Forward Shock Driven by the July 23 2012 Extreme Coronal Mass Ejection

    CERN Document Server

    Riley, Pete; Giacalone, Joe; Lario, David; Liu, Ying

    2015-01-01

    Late on July 23, 2012, the STEREO-A spacecraft encountered a fast forward shock driven by a coronal mass ejection launched from the Sun earlier that same day. The estimated travel time of the disturbance ($\\sim 20$ hrs), together with the massive magnetic field strengths measured within the ejecta ($> 100$nT), made it one of the most extreme events observed during the space era. In this study, we examine the properties of the shock wave. Because of an instrument malfunction, plasma measurements during the interval surrounding the CME were limited, and our approach has been modified to capitalize on the available measurements and suitable proxies, where possible. We were able to infer the following properties. First, the shock normal was pointing predominantly in the radial direction (${\\bf n} = 0.97 {\\bf e}_r -0.09 {\\bf e}_t -0.23 {\\bf e}_n$). Second, the angle between ${\\bf n}$ and the upstream magnetic field, $\\theta_{Bn}$, was estimated to be $\\approx 34^{\\circ}$, making the shock "quasi-parallel," and sup...

  8. Fundamental Studies on the Use of Laser-Driven Proton Beams for Fast Ignition

    Science.gov (United States)

    McGuffey, C.; Kim, J.; Beg, F. N.; Wei, M. S.; Chen, S. N.; Fuchs, J.; Nilson, P. M.; Theobald, W.; Habara, H.; Tanaka, K.; Yabuuchi, T.; Foord, M. E.; Patel, P. K.; McLean, H. S.; Roth, M.; McKenna, P.

    2015-11-01

    A short-pulse-laser-driven intense proton beam remains a candidate for Fast Ignition heater due to its focusability and high current. However, the proton current density necessary for FI in practice has never been produced in the laboratory and there are many physics issues that should be addressed using current and near-term facilities. For example, the extraction of sufficient proton charge from the short-pulse laser target could be evaluated with the multi-kilojoule NIF ARC laser. Transport of the beam through matter, such as a cone tip, and deposition in the fuel must be considered carefully as it will isochorically heat any material it enters and produce a rapidly-evolving, warm dense matter state with uncertain transport and stopping properties. Here we share experimental measurements of the proton spectra after passing through metal cones and foils taken with the kilojoule-class, multi-picosecond OMEGA EP and LFEX lasers. We also present complementary PIC simulations of beam generation and transport to and in the foils. Upcoming experiments to further evaluate proton beam performance in proton FI will also be outlined. This work was supported by the DOE/NNSA NLUF program, Contract DE-NA0002034 and by the AFOSR under Contract FA9550-14-1-0346.

  9. A close-coupling multi-antenna type radio frequency driven ion source.

    Science.gov (United States)

    Oka, Y; Shoji, T

    2012-02-01

    A newly close coupling multi-antenna type radio frequency driven ion source is tested for the purpose of essentially improving plasma coupling on the basis of our old type ion source, which reuses a NNBI (negative ion source for neutral beam injection) ion source used in 1∕5th scale of the Large Helical Device NNBI. The ion source and the antenna structure are described, and the efficient plasma production in terms of the positive ion saturation current (the current density) is studied. The source is made of a metal-walled plasma chamber which is desirable from the point of view of the structural toughness for fusion and industrial application, etc. At around 160 kW of rf input power, the ion saturation current density successfully reaches the 5 A∕cm(2) level with a gas pressure of 0.6-2 Pa in hydrogen for 10 ms pulse duration. The rf power efficiency of the plasma production with a close coupling configuration of the antenna is improved substantially compared to that with the previous antenna unit in the old type ion source. The power efficiency is assessed as competing with that of other types of sources.

  10. Single electron capture in fast ion-atom collisions

    Science.gov (United States)

    Milojević, Nenad

    2014-12-01

    Single-electron capture cross sections in collisions between fast bare projectiles and heliumlike atomic systems are investigated by means of the four-body boundary-corrected first Born (CB1-4B) approximation. The prior and post transition amplitudes for single charge exchange encompassing symmetric and asymmetric collisions are derived in terms of twodimensional real integrals in the case of the prior form and five-dimensional quadratures for the post form. The dielectronic interaction V12 = 1/r12 = 1/|r1 - r2| explicitly appears in the complete perturbation potential Vf of the post transition probability amplitude T+if. An illustrative computation is performed involving state-selective and total single capture cross sections for the p - He (prior and post form) and He2+, Li3+Be4+B5+C6+ - He (prior form) collisions at intermediate and high impact energies. We have also studied differential cross sections in prior and post form for single electron transfer from helium by protons. The role of dynamic correlations is examined as a function of increased projectile energy. Detailed comparisons with the measurements are carried out and the obtained theoretical cross sections are in reasonable agreement with the available experimental data.

  11. Filamentation instability of nonextensive current-driven plasma in the ion acoustic frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Khorashadizadeh, S. M., E-mail: smkhorashadi@birjand.ac.ir; Rastbood, E. [Physics Department of Birjand University, Birjand (Iran, Islamic Republic of); Niknam, A. R., E-mail: a-niknam@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)

    2014-12-15

    The filamentation and ion acoustic instabilities of nonextensive current-driven plasma in the ion acoustic frequency range have been studied using the Lorentz transformation formulas. Based on the kinetic theory, the possibility of filamentation instability and its growth rate as well as the ion acoustic instability have been investigated. The results of the research show that the possibility and growth rate of these instabilities are significantly dependent on the electron nonextensive parameter and drift velocity. Besides, the increase of electrons nonextensive parameter and drift velocity lead to the increase of the growth rates of both instabilities. In addition, the wavelength region in which the filamentation instability occurs is more stretched in the presence of higher values of drift velocity and nonextensive parameter. Finally, the results of filamentation and ion acoustic instabilities have been compared and the conditions for filamentation instability to be dominant mode of instability have been presented.

  12. Preface: Photon and fast Ion induced Processes in Atoms, MOlecules and Nanostructures (PIPAMON)

    Science.gov (United States)

    Kövér, László

    2016-02-01

    This Special Issue contains selected papers of contributions presented in the International Workshop on Photon and fast Ion induced Processes in Atoms, MOlecules and Nanostructures (PIPAMON), held between March 24 and 26, 2015 in Debrecen, Hungary. The venue, the Aquaticum Thermal and Wellness Hotel provided a pleasant "all-under-one-roof" environment for the event.

  13. Fast ion millimeter wave collective Thomson scattering diagnostics on TEXTOR and ASDEX upgrades

    DEFF Research Database (Denmark)

    Michelsen, S.; Korsholm, Søren Bang; Bindslev, H.

    2004-01-01

    Collective Thomson scattering (CTS) diagnostic systems for measuring fast ions in TEXTOR and ASDEX Upgrade are described in this article. Both systems use millimeter waves generated by gyrotrons as probing radiation and the scattered radiation is detected with heterodyne receivers having 40...

  14. On velocity-space sensitivity of fast-ion D-alpha spectroscopy

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Moseev, Dmitry

    2014-01-01

    The velocity-space observation regions and sensitivities in fast-ion Dα (FIDA) spectroscopy measurements are often described by so-called weight functions. Here we derive expressions for FIDA weight functions accounting for the Doppler shift, Stark splitting, and the charge-exchange reaction and ...

  15. Inversion methods for fast-ion velocity-space tomography in fusion plasmas

    DEFF Research Database (Denmark)

    Jacobsen, Asger Schou; Stagner, L.; Salewski, Mirko

    2016-01-01

    Velocity-space tomography has been used to infer 2D fast-ion velocity distribution functions. Here we compare the performance of five different tomographic inversion methods: truncated singular value decomposition, maximum entropy, minimum Fisher information and zeroth and first-order Tikhonov re...

  16. High-performance rechargeable batteries with fast solid-state ion conductors

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, Joseph C.

    2017-06-27

    A high-performance rechargeable battery using ultra-fast ion conductors. In one embodiment the rechargeable battery apparatus includes an enclosure, a first electrode operatively connected to the enclosure, a second electrode operatively connected to the enclosure, a nanomaterial in the enclosure, and a heat transfer unit.

  17. Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Bindslev, Henrik; Porte, L.

    2008-01-01

    of scattering locations and different resolved velocity components can be measured. The temporal resolution is 4 ms while the spatial resolution is similar to 10 cm depending on the scattering geometry. Fast-ion velocity distributions in a variety of scenarios are measured, including the evolution...

  18. Comparison of fast ion collective Thomson scattering measurements at ASDEX Upgrade with numerical simulations

    DEFF Research Database (Denmark)

    Salewski, Mirko; Meo, Fernando; Stejner Pedersen, Morten

    2010-01-01

    Collective Thomson scattering (CTS) experiments were carried out at ASDEX Upgrade to measure the one-dimensional velocity distribution functions of fast ion populations. These measurements are compared with simulations using the codes TRANSP/NUBEAM and ASCOT for two different neutral beam injection...

  19. Numerical studies of fast ion slowing down rates in cool magnetized plasma using LSP

    Science.gov (United States)

    Evans, Eugene S.; Kolmes, Elijah; Cohen, Samuel A.; Rognlien, Tom; Cohen, Bruce; Meier, Eric; Welch, Dale R.

    2016-10-01

    In MFE devices, rapid transport of fusion products from the core into the scrape-off layer (SOL) could perform the dual roles of energy and ash removal. The first-orbit trajectories of most fusion products from small field-reversed configuration (FRC) devices will traverse the SOL, allowing those particles to deposit their energy in the SOL and be exhausted along the open field lines. Thus, the fast ion slowing-down time should affect the energy balance of an FRC reactor and its neutron emissions. However, the dynamics of fast ion energy loss processes under the conditions expected in the FRC SOL (with ρe fast ions in a cool plasma. As we use explicit algorithms, these simulations must spatially resolve both ρe and λDe, as well as temporally resolve both Ωe and ωpe, increasing computation time. Scaling studies of the fast ion charge (Z) and background plasma density are in good agreement with unmagnetized slowing down theory. Notably, Z-scaling represents a viable way to dramatically reduce the required CPU time for each simulation. This work was supported, in part, by DOE Contract Number DE-AC02-09CH11466.

  20. Simple and Fast Scheme for Realizing Quantum Logic Gates in an Ion Trap

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2004-01-01

    We propose a simple and fast scheme to realize a controlled-NOT gate between two trapped ions using a resonant laser pulse. Our scheme allows the Rabi frequency of the laser field to be of the order of the vibrational frequency and thus the time required to complete the operation is greatly shortened, which is of importance in view of decoherence.

  1. Measurement and simulation of passive fast-ion D-alpha emission from the DIII-D tokamak

    Science.gov (United States)

    Bolte, Nathan G.; Heidbrink, William W.; Pace, David; Van Zeeland, Michael; Chen, Xi

    2016-11-01

    Spectra of passive fast-ion D-alpha (FIDA) light from beam ions that charge exchange with background neutrals are measured and simulated. The fast ions come from three sources: ions that pass through the diagnostic sightlines on their first full orbit, an axisymmetric confined population, and ions that are expelled into the edge region by instabilities. A passive FIDA simulation (P-FIDASIM) is developed as a forward model for the spectra of the first-orbit fast ions and consists of an experimentally-validated beam deposition model, an ion orbit-following code, a collisional-radiative model, and a synthetic spectrometer. Model validation consists of the simulation of 86 experimental spectra that are obtained using 6 different neutral beam fast-ion sources and 13 different lines of sight. Calibrated spectra are used to estimate the neutral density throughout the cross-section of the tokamak. The resulting 2D neutral density shows the expected increase toward each X-point with average neutral densities of 8× {{10}9}~\\text{c}{{\\text{m}}-3} at the plasma boundary and 1× {{10}11}~\\text{c}{{\\text{m}}-3} near the wall. Fast ions that are on passing orbits are expelled by the sawtooth instability more readily than trapped ions. In a sample discharge, approximately 1% of the fast-ion population is ejected into the high neutral density region per sawtooth crash.

  2. Quantification of the impact of large and small-scale instabilities on the fast-ion confinement in ASDEX Upgrade

    DEFF Research Database (Denmark)

    Geiger, B.; Weiland, M.; Mlynek, A.

    2015-01-01

    The confinement fast ions, generated by neutral beam injection (NBI), has been investigated at the ASDEX Upgrade tokamak. In plasmas that exhibit strong sawtooth crashes, a significant sawtooth-induced internal redistribution of mainly passing fast ions is observed, which is in very good agreemen...

  3. Experimental and simulated fast ion velocity distributions on collective Thomson scattering diagnostic in the Large Helical Device

    DEFF Research Database (Denmark)

    Nishiura, M.; Kubo, S.; Tanaka, K.

    2012-01-01

    We have developed a collective Thomson scattering diagnostic system in the LHD. The CTS spectrum spread is observed in the frequency region corresponding to the bulk and fast ions during NB injection. The NB originated fast ions are evaluated by the MORH code for understanding the measured CTS sp...

  4. Fast-ion redistribution due to sawtooth crash in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Bindslev, Henrik; Salewski, Mirko;

    2010-01-01

    Here we present collective Thomson scattering measurements of 1D fast-ion velocity distribution functions in neutral beam heated TEXTOR plasmas with sawtooth oscillations. Up to 50% of the fast ions in the centre are redistributed as a consequence of a sawtooth crash. We resolve various directions...

  5. Ultrafast opacity in borosilicate glass induced by picosecond bursts of laser-driven ions

    CERN Document Server

    Dromey, B; Adams, D; Prasad, R; Kakolee, K F; Stefanuik, R; Nersisyan, G; Sarri, G; Yeung, M; Ahmed, H; Doria, D; Dzelzainis, T; Jung, D; Kar, S; Marlow, D; Romagnani, L; Correa, A A; Dunne, P; Kohanoff, J; Schleife, A; Borghesi, M; Currell, F; Riley, D; Zepf, M; Lewis, C L S

    2014-01-01

    Direct investigation of ion-induced dynamics in matter on picosecond (ps, 10-12 s) timescales has been precluded to date by the relatively long nanosecond (ns, 10-9 s) scale ion pulses typically provided by radiofrequency accelerators1. By contrast, laser-driven ion accelerators provide bursts of ps duration2, but have yet to be applied to the study of ultrafast ion-induced transients in matter. We report on the evolution of an electron-hole plasma excited in borosilicate glass by such bursts. This is observed as an onset of opacity to synchronised optical probe radiation and is characterised by the 3.0 +/- 0.8 ps ion pump rise-time . The observed decay-time of 35 +/- 3 ps i.e. is in excellent agreement with modelling and reveals the rapidly evolving electron temperature (>10 3 K) and carrier number density (>10 17cm-3). This result demonstrates that ps laser accelerated ion bursts are directly applicable to investigating the ultrafast response of matter to ion interactions and, in particular, to ultrafast pu...

  6. Validation of fast-ion D-alpha spectrum measurements during EAST neutral-beam heated plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J., E-mail: juan.huang@ipp.ac.cn; Wu, C. R.; Hou, Y. M.; Chang, J. F.; Ding, S. Y.; Chen, Y. J.; Jin, Z.; Xu, Z.; Gao, W.; Wang, J. F.; Lyu, B.; Zang, Q.; Zhong, G. Q.; Hu, L.; Wan, B. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, 230031 Hefei, Anhui (China); Heidbrink, W. W.; Stagner, L.; Zhu, Y. B. [University of California, Irvine, California 92697 (United States); Hellermann, M. G. von [Diagnostic Team, ITER Organization, Route de Vinon-sur-Verdon 13067 St. Paul Lez Durance (France)

    2016-11-15

    To investigate the fast ion behavior, a fast ion D-alpha (FIDA) diagnostic system has been installed on EAST. Fast ion features can be inferred from the Doppler shifted spectrum of Balmer-alpha light from energetic hydrogenic atoms. This paper will focus on the validation of FIDA measurements performed using MHD-quiescent discharges in 2015 campaign. Two codes have been applied to calculate the D{sub α} spectrum: one is a Monte Carlo code, Fortran 90 version FIDASIM, and the other is an analytical code, Simulation of Spectra (SOS). The predicted SOS fast-ion spectrum agrees well with the measurement; however, the level of fast-ion part from FIDASIM is lower. The discrepancy is possibly due to the difference between FIDASIM and SOS velocity distribution function. The details will be presented in the paper to primarily address comparisons of predicted and observed spectrum shapes/amplitudes.

  7. Validation of fast-ion D-alpha spectrum measurements during EAST neutral-beam heated plasmas

    Science.gov (United States)

    Huang, J.; Heidbrink, W. W.; von Hellermann, M. G.; Stagner, L.; Wu, C. R.; Hou, Y. M.; Chang, J. F.; Ding, S. Y.; Chen, Y. J.; Zhu, Y. B.; Jin, Z.; Xu, Z.; Gao, W.; Wang, J. F.; Lyu, B.; Zang, Q.; Zhong, G. Q.; Hu, L.; Wan, B.

    2016-11-01

    To investigate the fast ion behavior, a fast ion D-alpha (FIDA) diagnostic system has been installed on EAST. Fast ion features can be inferred from the Doppler shifted spectrum of Balmer-alpha light from energetic hydrogenic atoms. This paper will focus on the validation of FIDA measurements performed using MHD-quiescent discharges in 2015 campaign. Two codes have been applied to calculate the Dα spectrum: one is a Monte Carlo code, Fortran 90 version FIDASIM, and the other is an analytical code, Simulation of Spectra (SOS). The predicted SOS fast-ion spectrum agrees well with the measurement; however, the level of fast-ion part from FIDASIM is lower. The discrepancy is possibly due to the difference between FIDASIM and SOS velocity distribution function. The details will be presented in the paper to primarily address comparisons of predicted and observed spectrum shapes/amplitudes.

  8. Ion beam driven resonant ion-cyclotron instability in a magnetized dusty plasma

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Ved; Vijayshri [School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi 110 068 (India); Sharma, Suresh C. [Department of Applied Physics, Delhi Technological University, Shahbad Daulatpur, Bawana Road, Delhi 110 042 (India); Gupta, Ruby [Department of Physics, Swami Shraddhanand College, University of Delhi, Alipur, Delhi 110 036 (India)

    2014-03-15

    Electrostatic ion cyclotron waves are excited by axial ion beam in a dusty plasma via Cerenkov and slow cyclotron interaction. The dispersion relation of the instability is derived in the presence of positively/negatively charged dust grains. The minimum beam velocity needed for the excitation is estimated for different values of relative density of negatively charged dust grains. It is shown that the minimum beam velocity needed for excitation increases as the charge density carried by dust increases. Temperature of electrons and ions, charge and mass of dust grains, external static magnetic field and finite boundary of dusty plasma significantly modify the dispersion properties of these waves and play a crucial role in the growth of resonant ion cyclotron instability. The ion cyclotron modes with phase velocity comparable to the beam velocity possess a large growth rate. The maximum value of growth rate increases with the beam density and scales as the one-third power of the beam density in Cerenkov interaction and is proportional to the square root of beam density in slow cyclotron interaction.

  9. Magnetically Driven Accretion Disk Winds and Ultra-fast Outflows in PG 1211+143

    Science.gov (United States)

    Fukumura, Keigo; Tombesi, Francesco; Kazanas, Demosthenes; Shrader, Chris; Behar, Ehud; Contopoulos, Ioannis

    2015-05-01

    We present a study of X-ray ionization of MHD accretion-disk winds in an effort to constrain the physics underlying the highly ionized ultra-fast outflows (UFOs) inferred by X-ray absorbers often detected in various sub classes of Seyfert active galactic nuclei (AGNs). Our primary focus is to show that magnetically driven outflows are indeed physically plausible candidates for the observed outflows accounting for the AGN absorption properties of the present X-ray spectroscopic observations. Employing a stratified MHD wind launched across the entire AGN accretion disk, we calculate its X-ray ionization and the ensuing X-ray absorption-line spectra. Assuming an appropriate ionizing AGN spectrum, we apply our MHD winds to model the absorption features in an XMM-Newton/EPIC spectrum of the narrow-line Seyfert, PG 1211+143. We find, through identifying the detected features with Fe Kα transitions, that the absorber has a characteristic ionization parameter of log (ξc[erg cm s-1]) ≃ 5-6 and a column density on the order of NH ≃ 1023 cm-2 outflowing at a characteristic velocity of vc/c ≃ 0.1-0.2 (where c is the speed of light). The best-fit model favors its radial location at rc ≃ 200 Ro (Ro is the black hole’s innermost stable circular orbit), with an inner wind truncation radius at Rt ≃ 30 Ro. The overall K-shell feature in the data is suggested to be dominated by Fe xxv with very little contribution from Fe xxvi and weakly ionized iron, which is in good agreement with a series of earlier analyses of the UFOs in various AGNs, including PG 1211+143.

  10. MAGNETICALLY DRIVEN ACCRETION DISK WINDS AND ULTRA-FAST OUTFLOWS IN PG 1211+143

    Energy Technology Data Exchange (ETDEWEB)

    Fukumura, Keigo [James Madison University, Harrisonburg, VA 22807 (United States); Tombesi, Francesco; Kazanas, Demosthenes; Shrader, Chris [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Behar, Ehud [Department of Physics, Technion, Haifa 32000 (Israel); Contopoulos, Ioannis, E-mail: fukumukx@jmu.edu [Research Center for Astronomy, Academy of Athens, Athens 11527 (Greece)

    2015-05-20

    We present a study of X-ray ionization of MHD accretion-disk winds in an effort to constrain the physics underlying the highly ionized ultra-fast outflows (UFOs) inferred by X-ray absorbers often detected in various sub classes of Seyfert active galactic nuclei (AGNs). Our primary focus is to show that magnetically driven outflows are indeed physically plausible candidates for the observed outflows accounting for the AGN absorption properties of the present X-ray spectroscopic observations. Employing a stratified MHD wind launched across the entire AGN accretion disk, we calculate its X-ray ionization and the ensuing X-ray absorption-line spectra. Assuming an appropriate ionizing AGN spectrum, we apply our MHD winds to model the absorption features in an XMM-Newton/EPIC spectrum of the narrow-line Seyfert, PG 1211+143. We find, through identifying the detected features with Fe Kα transitions, that the absorber has a characteristic ionization parameter of log (ξ{sub c}[erg cm s{sup −1}]) ≃ 5–6 and a column density on the order of N{sub H} ≃ 10{sup 23} cm{sup −2} outflowing at a characteristic velocity of v{sub c}/c ≃ 0.1–0.2 (where c is the speed of light). The best-fit model favors its radial location at r{sub c} ≃ 200 R{sub o} (R{sub o} is the black hole’s innermost stable circular orbit), with an inner wind truncation radius at R{sub t} ≃ 30 R{sub o}. The overall K-shell feature in the data is suggested to be dominated by Fe xxv with very little contribution from Fe xxvi and weakly ionized iron, which is in good agreement with a series of earlier analyses of the UFOs in various AGNs, including PG 1211+143.

  11. Advanced ion beam analysis of materials using ion-induced fast electron

    Energy Technology Data Exchange (ETDEWEB)

    Kudo, Hiroshi; Tanabe, Atsushi; Ishihara, Toyoyuki [Tsukuba Univ., Ibaraki (Japan)] [and others

    1997-03-01

    Recent progress in the study of high-energy shadowing effect using ion-induced electron spectroscopy is reported with emphasis on a possibility of determination of local electronic structure in solids, which has been a difficult problem to approach with other experimental techniques. We demonstrate real-space determination of covalent-bond electron distribution in Si crystal. The analysis technique may provide a new field of ion beam analysis of solids. (author)

  12. “Uphill” cation transport: A bioinspired photo-driven ion pump

    Science.gov (United States)

    Zhang, Zhen; Kong, Xiang-Yu; Xie, Ganhua; Li, Pei; Xiao, Kai; Wen, Liping; Jiang, Lei

    2016-01-01

    Biological ion pumps with active ionic transport properties lay the foundation for many life processes. However, few analogs have been produced because extra energy is needed to couple to this “uphill” process. We demonstrate a bioinspired artificial photo-driven ion pump based on a single polyethylene terephthalate conical nanochannel. The pumping process behaving as an inversion of zero-volt current can be realized by applying ultraviolet irradiation from the large opening. The light energy can accelerate the dissociation of the benzoic acid derivative dimers existing on the inner surface of nanochannel, which consequently produces more mobile carboxyl groups. Enhanced electrostatic interaction between the ions traversing the nanochannel and the charged groups on the inner wall is the key reason for the uphill cation transport behavior. This system creates an ideal experimental and theoretical platform for further development and design of various stimuli-driven and specific ion–selective bioinspired ion pumps, which anticipates wide potential applications in biosensing, energy conversion, and desalination. PMID:27774511

  13. ITER Plasma at Ion Cyclotron Frequency Domain: The Fusion Alpha Particles Diagnostics Based on the Stimulated Raman Scattering of Fast Magnetosonic Wave off High Harmonic Ion Bernstein Modes

    Science.gov (United States)

    Stefan, V. Alexander

    2014-10-01

    A novel method for alpha particle diagnostics is proposed. The theory of stimulated Raman scattering, SRS, of the fast wave and ion Bernstein mode, IBM, turbulence in multi-ion species plasmas, (Stefan University Press, La Jolla, CA, 2008). is utilized for the diagnostics of fast ions, (4)He (+2), in ITER plasmas. Nonlinear Landau damping of the IBM on fast ions near the plasma edge leads to the space-time changes in the turbulence level, (inverse alpha particle channeling). The space-time monitoring of the IBM turbulence via the SRS techniques may prove efficient for the real time study of the fast ion velocity distribution function, spatial distribution, and transport. Supported by Nikola Tesla Labs., La Jolla, CA 92037.

  14. The characteristics of rf-driven, multicusp, negative-ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Debiak, T.W.; Melnychuk, S.; Gammel, G.; Cole, M.; Solensten, L.; Sredniawski, J. (Grumman Accelerator Technology Development Laboratory, Bethpage, NY 11714 (United States)); Leung, K.N. (Lawrence Berkeley Laboratory, University of California, Berkeley, CA 94720 (United States))

    1992-10-05

    In this paper, we will present the initial results of our experiments designed to characterize an RF-driven, multicusp, negative-ion source. We will describe our experiences with suppression of RF pickup in the control system signal lines. Next, the characteristics of the extracted negative-ion beam will be described and compared with that from filament-based sources. The beam current, electron-to-ion ratio, and emittance as a function of RF power will be shown. Trends will also be shown with various electron suppression collar geometries and filter-rod field strengths. Finally, we will describe the change in beam current obtained when Cs is introduced into the plasma chamber using heated SAES dispensers.

  15. Operation of RF driven negative ion source in a pure-hydrogen mode

    Science.gov (United States)

    Abdrashitov, G.; Belchenko, Yu.; Ivanov, A. A.; Gusev, I.; Senkov, D.; Sanin, A.; Shikhovtsev, I.; Sotnikov, O.; Kondakov, A.

    2015-04-01

    The production of negative hydrogen ions in the radio-frequency driven long-pulsed source with external antenna is studied. RF drivers with various geometry of external antenna, Faraday shield and magnets at the rear flange were examined. H- beam extraction through the single emission aperture was performed in the source pure-hydrogen mode with no external seed of alkali additives. H- beam with ion emission current density up to 5 mA/cm2 and energy up to 75 keV was regularly obtained in the 1 s pulses of the pure-hydrogen mode. The regular temporal increase of H- ion production due to deposition of impurities on the plasma grid surface was recorded. The H- emission current density increased up to 9 mA/cm2 in this case.

  16. Instabilities Driven by a Pickup Ion Velocity Ring in the Heliosphere: Linear Theory and PIC Simulations

    Science.gov (United States)

    Liu, K.; Min, K.; Gary, S. P.; Wang, X.

    2016-12-01

    Linear dispersion analyses and two-dimensional electromagnetic particle-in-cell simulations are performed to study the kinetic plasma instabilities driven by a proton velocity ring with parameters (e.g., ring speed 10vA where vA is the Alfvén speed) relevant to the pickup ions in the distant solar wind. The results show that, besides the commonly expected Alfvén cyclotron instability with maximum growth at parallel propagation, mirror mode and ion Bernstein modes at oblique propagations are also unstable. While the enhanced waves from the Alfvén cyclotron instability mainly lead to pitch angle scattering of the ring protons, the other modes scatter the protons differently. The results also have implications for the pickup ions in the outer heliosheath.

  17. A compact broadband ion beam focusing device based on laser-driven megagauss thermoelectric magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Albertazzi, B., E-mail: bruno.albertazzi@polytechnique.edu [LULI, École Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); INRS-EMT, Varennes, Québec J3X 1S2 (Canada); Graduate School of Engineering, Osaka University, Suita, Osaka 565-087 (Japan); D' Humières, E. [CELIA, Universite de Bordeaux, Talence 33405 (France); Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Lancia, L.; Antici, P. [Dipartimento SBAI, Universita di Roma “La Sapienza,” Via A. Scarpa 16, 00161 Roma (Italy); Dervieux, V.; Nakatsutsumi, M.; Romagnani, L.; Fuchs, J., E-mail: Julien.fuchs@polytechnique.fr [LULI, École Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); Böcker, J.; Swantusch, M.; Willi, O. [Institut für Laser- und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf D-40225 (Germany); Bonlie, J.; Cauble, B.; Shepherd, R. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Breil, J.; Feugeas, J. L.; Nicolaï, P.; Tikhonchuk, V. T. [CELIA, Universite de Bordeaux, Talence 33405 (France); Chen, S. N. [LULI, École Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Sentoku, Y. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); and others

    2015-04-15

    Ultra-intense lasers can nowadays routinely accelerate kiloampere ion beams. These unique sources of particle beams could impact many societal (e.g., proton-therapy or fuel recycling) and fundamental (e.g., neutron probing) domains. However, this requires overcoming the beam angular divergence at the source. This has been attempted, either with large-scale conventional setups or with compact plasma techniques that however have the restriction of short (<1 mm) focusing distances or a chromatic behavior. Here, we show that exploiting laser-triggered, long-lasting (>50 ps), thermoelectric multi-megagauss surface magnetic (B)-fields, compact capturing, and focusing of a diverging laser-driven multi-MeV ion beam can be achieved over a wide range of ion energies in the limit of a 5° acceptance angle.

  18. Measurement of a 2D fast-ion velocity distribution function by tomographic inversion of fast-ion D-alpha spectra

    CERN Document Server

    Salewski, Mirko; Jacobsen, Asger Schou; Garcıa-Munoz, Manuel; Heidbrink, Bill; Korsholm, Soren Bang; Leipold, Frank; Madsen, Jens; Moseev, Dmitry; Nielsen, Stefan Kragh; Rasmussen, Jesper; Stejner, Morten; Tardini, Giovanni; Weiland, Markus

    2015-01-01

    We present the first measurement of a local fast-ion 2D velocity distribution function $f(v_\\parallel, v_\\perp)$. To this end, we heated a plasma in ASDEX Upgrade by neutral beam injection and measured spectra of fast-ion D-alpha (FIDA) light from the plasma center in three views simultaneously. The measured spectra agree very well with synthetic spectra calculated from a TRANSP/NUBEAM simulation. Based on the measured FIDA spectra alone, we infer $f(v_\\parallel, v_\\perp)$ by tomographic inversion. Salient features of our measurement of $f(v_\\parallel, v_\\perp)$ agree reasonably well with the simulation: the measured as well as the simulated $f(v_\\parallel, v_\\perp)$ are lopsided towards negative velocities parallel to the magnetic field, and they have similar shapes. Further, the peaks in the simulation of $f(v_\\parallel, v_\\perp)$ at full and half injection energies of the neutral beam also appear in the measurement at similar velocity-space locations. We expect that we can measure spectra in up to seven vi...

  19. Propagation of whistler waves driven by fine structured ion beams in the magnetotail

    Science.gov (United States)

    Burinskaya, T.; Schriver, D.; Ashour-Abdalla, M.

    1994-01-01

    In a previous paper, which examined the propagation of low-frequency whistler waves generated by ion beams in the Earth's plasma sheet boundary layer (PSBL), it was found that whistler waves driven in the PSBL are focused toward the central plasma sheet due to the global magnetotail inhomogeneities; this finding may help explain the observations of magnetic noise bursts in the tail (Burinskaya et al., 1993). In this paper the same phenomenon is examined, but this time a much more realistic model is used for the ion beam in the PSBL. While the PSBL has been modeled as a solid, homogeneous ion beams with a width of one Earth radius, observations and theoretical considerations have shown that PSBL ion beams actually have a decreasing velocity profile toward the plasma sheet and that the density of the beams within the PSBL can vary locally. We consider again the propagation and generation of electromagnetic waves but in the presence of fine structured ion beams in the PSBL. Our results show that whistler waves, generated quasi-parallel to the background magnetic field, can be trapped locally within small spatial regions where the ion beam density is enhanced compared to the density of the adjacent PSBL region. Wave spectra and nonlinear saturation mechanisms are discussed.

  20. Enabling High Fidelity Measurements of Energy and Pitch Angle for Escaping Energetic Ions with a Fast Ion Loss Detector

    Science.gov (United States)

    Chaban, R.; Pace, D. C.; Marcy, G. R.; Taussig, D.

    2016-10-01

    Energetic ion losses must be minimized in burning plasmas to maintain fusion power, and existing tokamaks provide access to energetic ion parameter regimes that are relevant to burning machines. A new Fast Ion Loss Detector (FILD) probe on the DIII-D tokamak has been optimized to resolve beam ion losses across a range of 30 - 90 keV in energy and 40° to 80° in pitch angle, thereby providing valuable measurements during many different experiments. The FILD is a magnetic spectrometer; once inserted into the tokamak, the magnetic field allows energetic ions to pass through a collimating aperture and strike a scintillator plate that is imaged by a wide view camera and narrow view photomultiplier tubes (PMTs). The design involves calculating scintillator strike patterns while varying probe geometry. Calculated scintillator patterns are then used to design an optical system that allows adjustment of the focus regions for the 1 MS/s resolved PMTs. A synthetic diagnostic will be used to determine the energy and pitch angle resolution that can be attained in DIII-D experiments. Work supported in part by US DOE under the Science Undergraduate Laboratory Internship (SULI) program and under DE-FC02-04ER54698.

  1. Active and Fast Particle Driven Alfvén Eigenmodes in Alcator C-Mod

    Science.gov (United States)

    Snipes, Joseph

    2004-11-01

    Alfvén eigenmodes (AEs) are studied in Alcator C-Mod to assess their stability in high density reactor relevant regimes where Te ≈ Ti and as a diagnostic tool. Stable AEs are excited in Ohmic plasmas by driving a plasma resonance with (3 - 7 kW) active MHD antennas in the range of the expected AE frequency. The antennas excite a wide toroidal mode spectrum with observed modes between 4 MW) with electron densities in the range of bar ne = 0.5 - 2 × 10^20 m-3. In the current rise phase, low midnmid = 1 - 3 unstable modes are observed with magnetic pick-up coils to rotate in the ion diamagnetic drift direction with frequencies that increase rapidly with time. Phase Contrast Imaging (PCI) density fluctuation measurements, instead, show similar modes at the same time but with frequencies changing more rapidly in time. Similar modes on JET, known as Alfvén Cascades (ACs), have the slope of the frequency change in time proportional to midnmid. This indicates that the PCI on C-Mod is more sensitive to higher order modes in the plasma core. Modeling of the ACs constrains the calculated q profile to be very flat with perhaps slightly reversed shear at q_min = 3. By varying the toroidal field, ACs were found to be more stable for an inboard ICRF resonance than for an outboard resonance. In the flattop, energetic particle modes (EPMs) and TAEs have also been observed to decrease in frequency and mode number with time up to a monster sawtooth collapse, indicating the role fast particles play in stabilizing sawteeth. Modeling of these sawtooth-related TAEs indicates a broad radial structure peaked well outside the q=1 surface with midnmid = 5 - 11 and multiple poloidal modes numbers.

  2. Trapping ions from a fast beam in a radio-frequency ion trap: The relaxation of the ion cloud and its resulting column density

    Science.gov (United States)

    Svendsen, Annette; Nielsen, Kristian M. E.; Pedersen, Henrik B.

    2014-06-01

    The relaxation of trapped Cl2- ions and their resulting column density in a multipole radio-frequency (RF) ion trap have been investigated after loading the trap from an initial fast-moving beam exploiting a mechanism described recently [A. Svendsen et al., Phys. Rev. A 87, 043410 (2013), 10.1103/PhysRevA.87.043410] where the injection is mediated through the exchange of energy between ions and the oscillating RF field. The temporal relaxation of the energy distribution of the trapped ion cloud was probed by observing the evolution of the resulting time-of-flight distribution of ions after extraction and fragment mass analysis in a quadrupole mass filter. The ion energy distribution was found to be essentially stationary after ˜20 ms. The resulting column density of trapped ions after relaxation was probed by two-dimensional position-resolved photodissociation of the trapped Cl2- ions. A detailed statistical analysis of the ion column density in the ring-electrode trap is given, and by comparison to the experimental data, a value of the maximum adiabaticity parameter of ηmax≃0.28 is inferred. It is further demonstrated how the present experimental system allows for time-resolved mass spectrometry by probing explicitly the populations of both parent (Cl2-) and daughter (Cl-) ions as a function of time after closing the trap and after laser irradiation. Finally, it is discussed how the setup can be used to obtain absolute photodissociation cross sections via a tomographic method without assumptions on the decay law for the trapped ions.

  3. Uniform heating of materials into the warm dense matter regime with laser-driven quasi-monoenergetic ion beams

    CERN Document Server

    Bang, W; Bradley, P A; Vold, E L; Boettger, J C; Fernández, J C

    2015-01-01

    In a recent experiment on the Trident laser facility, a laser-driven beam of quasi-monoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 eV and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable on Trident, with a finite energy spread of (delta E)/E ~ 20%, are expected to heat the targets more uniformly than a beam of 140 MeV aluminum ions with zero energy spread. The robustness of the expected heating uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.

  4. Studies of the fast ion energy spectra in TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Bustos, A. [Laboratorio Nacional de Fusion, EURATOM-CIEMAT, 28040 Madrid (Spain); Max-Planck-Institut fur Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Fontdecaba, J. M.; Arevalo, J. [Laboratorio Nacional de Fusion, EURATOM-CIEMAT, 28040 Madrid (Spain); Castejon, F.; Velasco, J. L. [Laboratorio Nacional de Fusion, EURATOM-CIEMAT, 28040 Madrid (Spain); Instituto de Biocomputacion y Fisica de los Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018 Zaragoza (Spain); Tereshchenko, M. [Instituto de Biocomputacion y Fisica de los Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018 Zaragoza (Spain)

    2013-02-15

    The dynamics of the neutral beam injection fast ions in the TJ-II stellarator is studied in this paper from both the theoretical and experimental points of view. The code Integrator of Stochastic Differential Equations for Plasmas (ISDEP) is used to estimate the fast ion distribution function in 3D:1D in real space and 2D in velocity space, considering the 3D structure of TJ-II, the electrostatic potential, non turbulent collisional transport, and charge exchange losses. The results of ISDEP are compared with the experimental data from the compact neutral particle analyzer, which measures the outgoing neutral flux spectra in the energy range E Element-Of (1-45) keV.

  5. Reduction of the U(VI) ion. A fast conductimetry study

    Energy Technology Data Exchange (ETDEWEB)

    Broszkiewicz, R.K. (Institute of Nuclear Chemistry and Technology, Warsaw (Poland)); Vojnovic, B.; Michael, B.D. (Mount Vernon Hospital, Northwood (UK). Gray Lab.)

    1991-01-01

    The reduction of U(VI) by e{sub aq}{sup -} was followed by means of fast conductimetry in acid and conductimetry and spectrophotometry in alkaline solutions. In alkaline solutions, the biomolecular rate constant of reaction between UO{sub 4}{sup 2-} and e{sub aq}{sup -} was determined. Analytical methods applied in this work were too fast to follow the slow disproportionation of produced U(V)-ion, but it has been observed that in alkaline solutions it probably goes via a dimeric ion (U(V)){sub 2}, which protonates with a rate {kappa}{sub 7} = 1.30 x 10{sup 5}s{sup -1}. (author).

  6. Comparison of collective Thomson scattering signals due to fast ions in ITER scenarios with fusion and auxiliary heating

    DEFF Research Database (Denmark)

    Salewski, Mirko; Asunta, O.; Eriksson, L.-G.

    2009-01-01

    to the alpha population in these frequency ranges. The exceptions are limited regions in space with some non-negligible signal due to beam ions or fast He-3 which give rise to about 30% and 10-20% of the CTS signal, respectively. In turn, the dominance of the alpha contribution implies that the effects...... scattering (CTS) signal for the proposed CTS diagnostic in ITER. It is of interest to determine the contributions of these fast ion populations to the CTS signal for large Doppler shifts of the scattered radiation since conclusions can mostly be drawn for the dominant contributor. In this study, distribution...... functions for fast deuterons, fast tritons, fast He-3 and the fusion born alphas are presented, revealing that fusion alphas dominate the measurable signal by an order of magnitude or more in the Doppler shift frequency ranges typical for fast ions. Hence the observable CTS signal can mostly be attributed...

  7. Design of fast ion conducting cathode materials for grid-scale sodium-ion batteries.

    Science.gov (United States)

    Wong, Lee Loong; Chen, Haomin; Adams, Stefan

    2017-03-15

    The obvious cost advantage as well as attractive electrochemical properties, including excellent cycling stability and the potential of high rate performance, make sodium-ion batteries prime candidates in the race to technically and commercially enable large-scale electrochemical energy storage. In this work, we apply our bond valence site energy modelling method to further the understanding of rate capabilities of a wide range of potential insertion-type sodium-ion battery cathode materials. We demonstrate how a stretched exponential function permits us to systematically quantify the rate performance, which in turn reveals guidelines for the design of novel sodium-ion battery chemistries suitable for high power, grid-scale applications. Starting from a diffusion relaxation model, we establish a semi-quantitative prediction of the rate-performance of half-cells from the structure of the cathode material that factors in dimensionality of Na(+) ion migration pathways, the height of the migration barriers and the crystallite size of the active material. With the help of selected examples, we also illustrate the respective roles of unoccupied low energy sites within the pathway and temperature towards the overall rate capability of insertion-type cathode materials.

  8. The effects of nonthermal electron distributions on ion-temperature-gradient driven drift-wave instabilities in electron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Batool, Nazia [Theoretical Plasma Physics Group, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); National Center of Physics (NCP), Quaid-i-Azam University campus, Islamabad (Pakistan); Masood, W. [National Center of Physics (NCP), Quaid-i-Azam University campus, Islamabad (Pakistan); Theoretical Plasma Physics Division, PINSTECH P. O. Nilore, Islamabad (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2012-08-15

    The effects of nonthermal electron distributions on electrostatic ion-temperature-gradient (ITG) driven drift-wave instabilities in the presence of equilibrium density, temperature, and magnetic field gradients are investigated here. By using Braginskii's transport equations for ions and Cairns as well as Kappa distribution for electrons, the coupled mode equations are derived. The modified ITG driven modes are derived, and it is found both analytically as well as numerically that the nonthermal distribution of electrons significantly modify the real frequencies as well as the growth rate of the ITG driven drift wave instability. The growth rate of ion-temperature-gradient driven instability is found to be maximum for Cairns, intermediate for Kappa, and minimum for the Maxwellian distributed electron case. The results of present investigation might be helpful to understand several wave phenomena in space and laboratory plasmas in the presence of nonthermal electrons.

  9. Influence of phase separation for surfactant driven pattern formation during ion beam erosion

    Energy Technology Data Exchange (ETDEWEB)

    Hofsaess, Hans; Zhang, Kun; Vetter, Ulrich; Bobes, Omar; Pape, Andre; Gehrke, Hans-Gregor; Broetzmann, Marc [II. Physikalisches Institut, Goettingen Univ. (Germany)

    2012-07-01

    We will present results on metal surfactant driven self-organized pattern formation on surfaces by ion beam erosion, with a focus on the role of phase separation for the initial steps of pattern formation. Si substrates were irradiated with 5 keV Xe ions at normal incidence and ion fluences up to 5.10{sup 17} Xe/cm{sup 2} under continuous deposition of surfactant atoms. In the absence of such surfactants uniform flat surfaces are obtained, while in the presence of Fe and Mo surfactants pronounced patterns like dots, combinations of dots and ripples with wavelengths around 100 nm are generated. The surfactant coverage and deposition direction determine the pattern type and the pattern orientation, respectively. A critical steady-state coverage for onset of dot formation and onset of ripple formation is in the range of 10{sup 15} and 5.10{sup 15} Xe/cm{sup 2}. The steady-state surface region consists of a thin amorphous metal silicide layer with high metal concentration in the ripple and dot regions. Pattern formation is explained by ion induced diffusion and phase separation of the initially flat amorphous silicide layer and subsequent ion beam erosion with composition dependent sputter yield. To investigate the role of initial phase separation we additionally compare the pattern formation for different other metal surfactants.

  10. Ion acceleration at CME-driven shocks near the Earth and the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Desai, Mihir; Dayeh, Maher; Ebert, Robert; Smith, Charles; Mason, Glenn; Li, G. [Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas, 78238 (United States); University of New Hampshire, Durham, New Hampshire, 03824 (United States); Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland, 20724 (United States); Center for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, Al 35899 (United States)

    2012-11-20

    We compare the behavior of heavy ion spectra during an Energetic Storm Particle (ESP) event that exhibited clear evidence of wave excitation with that observed during an intense, large gradual Solar Energetic Particle (SEP) event in which the associated <0.2 MeV/nucleon ions are delayed >12 hr. We interpret that the ESP event is an example of the first-order Fermi acceleration process where enhancements in the magnetic field power spectral densities around local ion cyclotron frequency {nu}{sub pc} indicate the presence of Alfven waves excited by accelerated protons streaming away from the in-situ interplanetary shock. The softening or unfolding of the CNO energy spectrum below {approx}200 keV/nucleon and the systematic organization of the Fe and O spectral roll-overs with the E/q ratio during the ESP event are likely due to M/Q-dependent trapping and scattering of the heavy ions by the proton-excited waves. Based on striking similarities in the spectral behavior observed upstream of both, the ESP and the SEP event, we suggest that coupling between proton-generated Alfven waves and energetic ions is also operating at the distant CME shock during the large, gradual SEP event, thereby providing us with a new, powerful tool to remotely probe the roles of shock geometries and wave-particle interactions at near-Sun CME-driven shocks.

  11. Energetic-ion-driven global instabilities in stellarator/helical plasmas and comparison with tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Toi, K. [National Institute for Fusion Science, Toki, Japan; Ogawa, K. [Nagoya University, Japan; Isobe, M. [National Institute for Fusion Science, Toki, Japan; Osakabe, M. [National Institute for Fusion Science, Toki, Japan; Spong, Donald A [ORNL; Todo, Yasushi [National Institute for Fusion Science, Toki, Japan

    2011-01-01

    Comprehensive understanding of energetic-ion-driven global instabilities such as Alfven eigenmodes (AEs) and their impact on energetic ions and bulk plasma is crucially important for tokamak and stellarator/helical plasmas and in the future for deuterium-tritium (DT) burning plasma experiments. Various types of global modes and their associated enhanced energetic ion transport are commonly observed in toroidal plasmas. Toroidicity-induced AEs and ellipticity-induced AEs, whose gaps are generated through poloidal mode coupling, are observed in both tokamak and stellarator/helical plasmas. Global AEs and reversed shear AEs, where toroidal couplings are not as dominant were also observed in those plasmas. Helicity induced AEs that exist only in 3D plasmas are observed in the large helical device (LHD) and Wendelstein 7 Advanced Stellarator plasmas. In addition, the geodesic acoustic mode that comes from plasma compressibility is destabilized by energetic ions in both tokamak and LHD plasmas. Nonlinear interaction of these modes and their influence on the confinement of the bulk plasma as well as energetic ions are observed in both plasmas. In this paper, the similarities and differences in these instabilities and their consequences for tokamak and stellarator/helical plasmas are summarized through comparison with the data sets obtained in LHD. In particular, this paper focuses on the differences caused by the rotational transform profile and the 2D or 3D geometrical structure of the plasma equilibrium. Important issues left for future study are listed.

  12. High-definition velocity-space tomography of fast-ion dynamics

    Science.gov (United States)

    Salewski, M.; Geiger, B.; Jacobsen, A. S.; Hansen, P. C.; Heidbrink, W. W.; Korsholm, S. B.; Leipold, F.; Madsen, J.; Moseev, D.; Nielsen, S. K.; Nocente, M.; Odstrčil, T.; Rasmussen, J.; Stagner, L.; Stejner, M.; Weiland, M.; the ASDEX Upgrade Team

    2016-10-01

    Velocity-space tomography of the fast-ion distribution function in a fusion plasma is usually a photon-starved tomography method due to limited optical access and signal-to-noise ratio of fast-ion D α (FIDA) spectroscopy as well as the strive for high-resolution images. In high-definition tomography, prior information makes up for this lack of data. We restrict the target velocity space through the measured absence of FIDA light, impose phase-space densities to be non-negative, and encode the known geometry of neutral beam injection (NBI) sources. We further use a numerical simulation as prior information to reconstruct where in velocity space the measurements and the simulation disagree. This alternative approach is demonstrated for four-view as well as for two-view FIDA measurements. The high-definition tomography tools allow us to study fast ions in sawtoothing plasmas and the formation of NBI peaks at full, half and one-third energy by time-resolved tomographic movies.

  13. Flux-driven gyrokinetic simulations of ion turbulent transport at low magnetic shear

    Energy Technology Data Exchange (ETDEWEB)

    Sarazin, Y; Strugarek, A; Dif-Pradalier, G; Abiteboul, J; Allfrey, S; Garbet, X; Ghendrih, Ph; Grandgirard, V; Latu, G, E-mail: yanick.sarazin@cea.fr

    2010-11-01

    Ion Temperature Gradient driven turbulence is investigated with the global full-f gyrokinetic code GYSELA for different magnetic equilibria. Reversed shear and monotonous q profile cases do not exhibit dramatic changes nor in the dynamics nor in the level of turbulence, leading to similar mean profiles. Especially, no transport barrier is observed in the vicinity of s = 0 in the general case, although the radial extent of the gap without resonant modes is larger than the typical turbulence correlation length. Conversely, a transport barrier is found to develop in the gap region if non resonant modes are artificially suppressed from the simulation. Such simulations tend to reconcile previously published contradictory results, while extending the analysis to more realistic flux-driven gyrokinetic regimes.

  14. Photoelectron momentum distributions of the hydrogen molecular ion driven by multicycle near-infrared laser pulses

    Science.gov (United States)

    Murakami, Mitsuko; Chu, Shih-I.

    2016-10-01

    The photoelectron momentum distributions (PMDs) of the hydrogen molecular ion H2+ driven by strong near-infrared laser pulses are studied based on the ab initio numerical solution of the time-dependent Schrödinger equation and the Volkov wave propagation. Both linear and circular polarization are considered, in accordance with the recent experiment by M. Odenweller et al. [Phys. Rev. A 89, 013424 (2014), 10.1103/PhysRevA.89.013424]. We will discuss the difference between the molecular (diatomic) and the atomic PMDs and the effect of molecular potential to the photoelectron energy. In particular, we demonstrate that the above-threshold ionization spectra of H2+ could upshift their energy when driven by a linearly polarized laser field parallel to the molecular axis.

  15. Dual Ion Spectrometers and Their Calibration for the Fast Plasma Investigation on NASA's Magnetospheric Multiscale Mission

    Science.gov (United States)

    Coffey, V. N.; Chandler, M. O.

    2017-01-01

    The scientific target of NASA's Magnetospheric Multiscale (MMS) mission is to study the fundamentally important phenomenon of magnetic reconnection. Theoretical models of this process predict a small size, on the order of hundred kilometers, for the ion diffusion region where ions are demagnetized at the dayside magnetopause. This region may typically sweep over the spacecraft at relatively high speeds of 50 km/s, requiring the fast plasma investigation (FPI) instrument suite to have an extremely high time resolution for measurements of the 3D particle distribution functions. As part of the FPI on MMS, the 16 dual ion spectrometers (DIS) will provide fast (150 ms) 3D ion velocity distributions, from 10 to 30,000 eV/q, by combining the measurements from four dual spectrometers on each of four MMS spacecraft. For any multispacecraft mission, the response uniformity among the spectrometer set assumes an enhanced importance. Due to these demanding instrument requirements and the effort of calibrating more than 32 sensors (16 × 2) within a tight schedule, a highly systematic and precise calibration was required for measurement repeatability. To illustrate how this challenge was met, a brief overview of the FPI DIS was presented with a detailed discussion of the calibration method of approach and implementation. Finally, a discussion of DIS performance results, their unit-to-unit variation, and the lessons learned from this calibration effort are presented.

  16. Fast heavy-ion radiation damage of glycine in aqueous solution

    Science.gov (United States)

    Nomura, Shinji; Tsuchida, Hidetsugu; Furuya, Ryosuke; Majima, Takuya; Itoh, Akio

    2016-12-01

    Fast heavy-ion radiolysis of biomolecules in aqueous solution is investigated for an atomistic understanding of radiation damage to normal cells during heavy-particle beam therapy. The smallest amino acid glycine was used as a model biomaterial. Microjets of aqueous glycine solutions under vacuum were irradiated with 4.0-MeV carbon ions corresponding to energies in the Bragg peak region. To understand the effects of the water environment on molecular damage, the yield of glycine dissociation was measured by secondary ion mass spectroscopy. The yield was significantly reduced relative to gas-phase glycine targets. This implies that the numerous water molecules surrounding a single glycine molecule act as a buffer that suppresses dissociation. This is an environmental effect similar to that observed for other biomolecular cluster targets.

  17. Review of the Remaining Useful Life Prognostics of Vehicle Lithium-Ion Batteries Using Data-Driven Methodologies

    Directory of Open Access Journals (Sweden)

    Lifeng Wu

    2016-05-01

    Full Text Available Lithium-ion batteries are the primary power source in electric vehicles, and the prognosis of their remaining useful life is vital for ensuring the safety, stability, and long lifetime of electric vehicles. Accurately establishing a mechanism model of a vehicle lithium-ion battery involves a complex electrochemical process. Remaining useful life (RUL prognostics based on data-driven methods has become a focus of research. Current research on data-driven methodologies is summarized in this paper. By analyzing the problems of vehicle lithium-ion batteries in practical applications, the problems that need to be solved in the future are identified.

  18. Toward integrated laser-driven ion accelerator systems at the photo-medical research center in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, P.R., E-mail: bolton.paul@jaea.go.j [Photo-Medical Research Center, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa-shi, Kyoto 619-0215 (Japan); Hori, T.; Kiriyama, H.; Mori, M.; Sakaki, H. [Photo-Medical Research Center, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa-shi, Kyoto 619-0215 (Japan); Sutherland, K. [Hokkaido University, School of Medicine, Sapporo-shi, Kita-ku, Kita 12 Jo, Nishi 5 Chome 060-0812 (Japan); Suzuki, M. [Photo-Medical Research Center, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa-shi, Kyoto 619-0215 (Japan); Wu, J. [SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA (United States); Yogo, A. [Photo-Medical Research Center, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa-shi, Kyoto 619-0215 (Japan)

    2010-08-01

    Goals and early progress at the Photo-Medical Research Center are summarized. Laser-driven ion beam radiotherapy can require compact repetition-rated laser systems with peak powers approaching the PW level. Laser development at PMRC is outlined. Our parallel experimental and simulation efforts aimed at the development of a prototype ion beamline as an integrated laser-driven ion accelerator system are presented. In addition some of our first medical and radiobiological experimental investigations, proton-induced double strand breaking in human cancer cells and simulations of optimum dose distributions for ocular melanoma are discussed. Recommended components of a balanced and comprehensive PMRC agenda are given.

  19. Water rotational jump driven large amplitude molecular motions of nitrate ions in aqueous potassium nitrate solution

    CERN Document Server

    Banerjee, Puja; Bagchi, Biman

    2016-01-01

    Molecular dynamics simulations of aqueous potassium nitrate solution reveal a highly complex rotational dynamics of nitrate ions where, superimposed on the expected continuous Brownian motion, are large amplitude angular jumps that are coupled to and at least partly driven by similar large amplitude jump motions in water molecules which are associated with change in the hydrogen bonded water molecule. These jumps contribute significantly to rotational and translational motions of these ions. We explore the detailed mechanism of these correlated (or, coupled) jumps and introduce a new time correlation function to decompose the coupled orientational- jump dynamics of solvent and solute in the aqueous electrolytic solution. Time correlation function provides for the unequivocal determination of the time constant involved in orientational dynamics originating from making and breaking of hydrogen bonds. We discover two distinct mechanisms-both are coupled to density fluctuation but are of different types.

  20. Density bunching effects in a laser-driven, near-critical density plasma for ion acceleration

    Science.gov (United States)

    Ettlinger, Oliver; Sahai, Aakash; Hicks, George; Ditter, Emma-Jane; Dover, Nicholas; Chen, Yu-Hsin; Helle, Michael; Gordon, Daniel; Ting, Antonio; Polyanskiy, Mikhail; Pogorelsky, Igor; Babzien, Marcus; Najmudin, Zulfikar

    2016-10-01

    We present work investigating the interaction of relativistic laser pulses with near-critical density gas targets exhibiting pre-plasma scale lengths of several laser wavelengths. Analytical and computational modelling suggest that the interaction dynamics in a low-Z plasma is a direct result of induced density bunching up to the critical surface. In fact, these bunches can themselves become overcritical and experience significant radiation pressure, accelerating ions to higher energies compared to an ``idealised'' plasma slab target. This work will be used to help explain the observation of ion energies exceeding those predicted by radiation pressure driven hole-boring in recent experiments using the TW CO2 laser at the Accelerator Test Facility at Brookhaven National Laboratory.

  1. Versatile microwave-driven trapped ion spin system for quantum information processing.

    Science.gov (United States)

    Piltz, Christian; Sriarunothai, Theeraphot; Ivanov, Svetoslav S; Wölk, Sabine; Wunderlich, Christof

    2016-07-01

    Using trapped atomic ions, we demonstrate a tailored and versatile effective spin system suitable for quantum simulations and universal quantum computation. By simply applying microwave pulses, selected spins can be decoupled from the remaining system and, thus, can serve as a quantum memory, while simultaneously, other coupled spins perform conditional quantum dynamics. Also, microwave pulses can change the sign of spin-spin couplings, as well as their effective strength, even during the course of a quantum algorithm. Taking advantage of the simultaneous long-range coupling between three spins, a coherent quantum Fourier transform-an essential building block for many quantum algorithms-is efficiently realized. This approach, which is based on microwave-driven trapped ions and is complementary to laser-based methods, opens a new route to overcoming technical and physical challenges in the quest for a quantum simulator and a quantum computer.

  2. Toward high-energy laser-driven ion beams: Nanostructured double-layer targets

    Science.gov (United States)

    Passoni, M.; Sgattoni, A.; Prencipe, I.; Fedeli, L.; Dellasega, D.; Cialfi, L.; Choi, Il Woo; Kim, I. Jong; Janulewicz, K. A.; Lee, Hwang Woon; Sung, Jae Hee; Lee, Seong Ku; Nam, Chang Hee

    2016-06-01

    The development of novel target concepts is crucial to make laser-driven acceleration of ion beams suitable for applications. We tested double-layer targets formed of an ultralow density nanostructured carbon layer (˜7 mg/cm 3 , 8 - 12 μ m -thick) deposited on a μ m -thick solid Al foil. A systematic increase in the total number of the accelerated ions (protons and C6 + ) as well as enhancement of both their maximum and average energies was observed with respect to bare solid foil targets. Maximum proton energies up to 30 MeV were recorded. Dedicated three-dimensional particle-in-cell simulations were in remarkable agreement with the experimental results, giving clear indication of the role played by the target nanostructures in the interaction process.

  3. Isotopic dependence of impurity transport driven by ion temperature gradient turbulence

    CERN Document Server

    Guo, Weixin; Zhuang, Ge

    2016-01-01

    Hydrogenic ion mass effects, namely the isotopic effects on impurity transport driven by ion temperature gradient (ITG) turbulence are investigated using gyrokinetic theory. For non-trace impurities, changing from hydrogen (H) to deuterium (D), and to tritium (T) plasmas, the outward flux for lower (higher) ionized impurities or for lighter (heavier) impurities is found to decrease (increase), although isotopic dependence of ITG linear growth rate is weak. This is mainly due to the decrease of outward (inward) convection, while the isotopic dependence of diffusion is relatively weak. In addition, the isotopic effects reduce (enhance) the impurity flux of fully ionized carbon (C6+) for weaker (stronger) magnetic shear. In trace impurity limit, the isotopic effects are found to reduce the accumulation of high-Z tungsten (W). Moreover, the isotopic effects on the peaking factor (PF) of trace high-Z W get stronger with stronger magnetic shear.

  4. Influence of ion outflow in coupled geospace simulations: 2. Sawtooth oscillations driven by physics-based ion outflow

    Science.gov (United States)

    Varney, R. H.; Wiltberger, M.; Zhang, B.; Lotko, W.; Lyon, J.

    2016-10-01

    We present the first simulations of magnetospheric sawtooth oscillations under steady solar wind conditions that are driven internally by heavy ion outflow from a physics-based model. The simulations presented use the multifluid Lyon-Fedder-Mobarry magnetohydrodynamics model two-way coupled to the ionosphere/polar wind model (IPWM). Depending on the type of wave-particle interactions utilized within IPWM, the coupled simulations exhibit either sawtooth oscillations or steady magnetospheric convection. Contrasting the simulations that do and do not develop sawtooth oscillations yields insights into the relationship between outflow and sawtooth oscillations. The total outflow rate is not an adequate predictor of the convection mode that will emerge. The simulations that develop sawtooth oscillations are characterized by intense outflow concentrated in the midnight auroral region. This outflow distribution mass loads the tail reconnection region without excessively mass loading the dayside reconnection region and leads to an imbalance between the dayside and nightside reconnection rates.

  5. ITER fast ion collective Thomson scattering, conceptual design of 60 GHz system

    Energy Technology Data Exchange (ETDEWEB)

    Meo, F.; Bindslev, H.; Korsholm, S.B.

    2007-08-15

    The collective Thomson scattering diagnostic for ITER at the 60 GHz range is capable of measuring the fast ion distribution parallel and perpendicular to the magnetic field at different radial locations simultaneously. The design is robust technologically with no moveable components near the plasma. The fast ion CTS diagnostic consists of two separate systems. Each system has its own RF launcher and separate set of detectors. The first system measures the perpendicular component of the fast ion velocity distribution. It consists of radially directed RF launcher and receiver, both located in the equatorial port on the low field side (LFS). This system will be referred to by the acronym LFS-BS system referring to the location of the receiver and the fact that it measures backscattered radiation. The second part of the CTS diagnostic measures the parallel component of the fast ion distribution. It consists of an RF launcher located in the mid-plane port on the LFS and a receiver mounted on the inner vacuum vessel wall that views the plasma from between two blanket modules. This system will be referred to as HFS-FS referring to the location of the receivers and that they measure forward scattered radiation. The design of both LFS-BS and HFS-FS receivers is aimed at measuring at different spatial locations simultaneously with no moveable components near the plasma. This report is a preliminary study of the hardware design and engineering constraints for this frequency range. Section 2 conceptually describes the two systems and their main components. Section 3 clarifies the impact of design parameters such as beam widths and scattering angle on the CTS measurements. With this in hand, the ITER measurement requirements are translated into constraints on the CTS system designs. An important result in this section is that systems can be designed inside these constraints. Section 4 outlines the technical feasibility and describes in more detail the design and the engineering

  6. LSP simulations of fast ions slowing down in cool magnetized plasma

    Science.gov (United States)

    Evans, Eugene S.; Cohen, Samuel A.

    2015-11-01

    In MFE devices, rapid transport of fusion products, e.g., tritons and alpha particles, from the plasma core into the scrape-off layer (SOL) could perform the dual roles of energy and ash removal. Through these two processes in the SOL, the fast particle slowing-down time will have a major effect on the energy balance of a fusion reactor and its neutron emissions, topics of great importance. In small field-reversed configuration (FRC) devices, the first-orbit trajectories of most fusion products will traverse the SOL, potentially allowing those particles to deposit their energy in the SOL and eventually be exhausted along the open field lines. However, the dynamics of the fast-ion energy loss processes under conditions expected in the FRC SOL, where the Debye length is greater than the electron gyroradius, are not fully understood. What modifications to the classical slowing down rate are necessary? Will instabilities accelerate the energy loss? We use LSP, a 3D PIC code, to examine the effects of SOL plasma parameters (density, temperature and background magnetic field strength) on the slowing down time of fast ions in a cool plasma with parameters similar to those expected in the SOL of small FRC reactors. This work supported by DOE contract DE-AC02-09CH11466.

  7. Antenna design for fast ion collective Thomson scattering diagnostic for the international thermonuclear experimental reactor.

    Science.gov (United States)

    Leipold, F; Furtula, V; Salewski, M; Bindslev, H; Korsholm, S B; Meo, F; Michelsen, P K; Moseev, D; Nielsen, S K; Stejner, M

    2009-09-01

    Fast ion physics will play an important role for the international thermonuclear experimental reactor (ITER), where confined alpha particles will affect and be affected by plasma dynamics and thereby have impacts on the overall confinement. A fast ion collective Thomson scattering (CTS) diagnostic using gyrotrons operated at 60 GHz will meet the requirements for spatially and temporally resolved measurements of the velocity distributions of confined fast alphas in ITER by evaluating the scattered radiation (CTS signal). While a receiver antenna on the low field side of the tokamak, resolving near perpendicular (to the magnetic field) velocity components, has been enabled, an additional antenna on the high field side (HFS) would enable measurements of near parallel (to the magnetic field) velocity components. A compact design solution for the proposed mirror system on the HFS is presented. The HFS CTS antenna is located behind the blankets and views the plasma through the gap between two blanket modules. The viewing gap has been modified to dimensions 30x500 mm(2) to optimize the CTS signal. A 1:1 mock-up of the HFS mirror system was built. Measurements of the beam characteristics for millimeter-waves at 60 GHz used in the mock-up agree well with the modeling.

  8. Fast Ion Effects During Test Blanket Module Simulation Experiments in DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, G J; Ellis, R; Gorelenkova, M; Heidbrink, W W; Kurki-Suonio, T; Nazikian, R; Salmi, A; Schaffer, M J; Shinohara, K; Snipes, J A; Spong, D A; Koskela, T

    2011-06-03

    Fast beam-ion losses were studied in DIII-D in the presence of a scaled mockup of two Test Blanket Modules (TBM) for ITER. Heating of the protective tiles on the front of the TBM surface was found when neutral beams were injected and the TBM fields were engaged. The fast-ion core confinement was not significantly affected. Different orbit-following codes predict the formation of a hot spot on the TBM surface arising from beam-ions deposited near the edge of the plasma. The codes are in good agreement with each other on the total power deposited at the hot spot predicting an increase in power with decreasing separation between the plasma edge and the TBM surface. A thermal analysis of the heat flow through the tiles shows that the simulated power can account for the measured tile temperature rise. The thermal analysis, however, is very sensitive to the details of the localization of the hot spot which is predicted to be different among the various codes.

  9. Fast-ion effects during test blanket module simulation experiments in DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, G. [Princeton Plasma Physics Laboratory (PPPL); Budny, R. V. [Princeton Plasma Physics Laboratory (PPPL); Ellis, R. [Princeton Plasma Physics Laboratory (PPPL); Gorelenkova, M. [Princeton Plasma Physics Laboratory (PPPL); Heidbrink, W. [University of California, Irvine; Kurki-Suonio, T. [Aalto University, Finland; Nazikian, Raffi [Princeton Plasma Physics Laboratory (PPPL); Saimi, A. [Aalto University, Finland; Schaffer, M. J. [General Atomics, San Diego; Shinohara, K. [Japan Atomic Energy Agency (JAEA), Naka; Snipes, J. A. [ITER Organization, Cadarache, France; Spong, Donald A [ORNL; Koskela, T. [Aalto University, Finland; Van Zeeland, Michael [General Atomics

    2011-01-01

    Fast beam-ion losses were studied in DIII-D in the presence of a scaled mock-up of two test blanket modules (TBM) for ITER. Heating of the protective tiles on the front of the TBM surface was found when neutral beams were injected and the TBM fields were engaged. The fast-ion core confinement was not significantly affected. Different orbit-following codes predict the formation of a hot spot on the TBM surface arising from beam ions deposited near the edge of the plasma. The codes are in good agreement with each other on the total power deposited at the hot spot, predicting an increase in power with decreasing separation between the plasma edge and the TBM surface. A thermal analysis of the heat flow through the tiles shows that the simulated power can account for the measured tile temperature rise. The thermal analysis, however, is very sensitive to the details of the localization of the hot spot, which is predicted to be different among the various codes.

  10. Structural and fast ion transport properties of glassy and amorphous materials

    Energy Technology Data Exchange (ETDEWEB)

    Whitmore, D.H.; Georgopoulos, P.

    1989-11-01

    This research has dealt with ionic conductivity in two classes of electrolytes. Solid inorganic, as well as polymer. In the former case, a structural characterization study of the fast Ag{sup +} ion conducting glassy electrolyte Ag{sub 0.25}Ge{sub 0.19}Se{sub 0.56} was undertaken by means of differential anomalous x-ray scattering techniques. The Ag{sup +} ion transport behavior was probed with the aid of complex impedance spectroscopy and pulsed field gradient NMR measurements of the Ag{sup +} ion diffusivity. We found evidence suggesting that short (3.1--3.5 A) Ag-Ag distances are present. The observed prefactor for conductivity suggests that the number of mobile Ag{sup +} ions in this glass is significantly less than expected from its stoichiometry. The transport property results were examined in the light of our structural findings and analyses were attempted in terms of some reasonable microscopic models. The other major aspect of this research, dealing with amorphous poly(ethylene glycol)-LiCF{sub 3}SO{sub 3} electrolytes, involved measurements, via the pulsed field gradient NMR method, of the diffusivity of the polymer host, the cation (Li{sup +}) and the anion (CF{sub 3}SO{sub 3}{sup -}) in these complexes and the ionic conductivity, via complex impedance spectroscopy. Based on the conductivity prefactors, it appears that these amorphous polymer electrolytes exhibit classical Meyer-Nelder behavior; moreover, our ion transport results could be rationalized in terms of an ion association model (involving ion pairs and higher order aggregates).

  11. A Comment on Interaction of Lower Hybrid Waves with the Current-Driven Ion-Acoustic Instability

    DEFF Research Database (Denmark)

    Schrittwieser, R.; Juul Rasmussen, Jens

    1985-01-01

    Majeski et al. (1984) have investigated the interaction between the current-driven 'ion-acoustic' instability and high frequency lower hybrid waves. The 'ion-acoustic' instability was excited by drawing an electron current through the plasma column of a single-ended Q-machine by means of a positi......Majeski et al. (1984) have investigated the interaction between the current-driven 'ion-acoustic' instability and high frequency lower hybrid waves. The 'ion-acoustic' instability was excited by drawing an electron current through the plasma column of a single-ended Q-machine by means...... of a positively biased cold plate. Schmittwieser et al. do not believe that the observed instability is of the ion-acoustic type but that it is rather the so-called potential relaxation instability....

  12. Effect of dipolar ions on the entropy-driven polymerization of tobacco mosaic virus protein.

    Science.gov (United States)

    Lauffer, M A; Shalaby, R A

    1985-11-01

    The effect of the dipolar ions, glycine, glycylglycine, and glycylglycylglycine on the polymerization of tobacco mosaic virus (TMV) protein has been studied by the methods of light scattering and ultracentrifugation. All three dipolar ions promote polymerization. The major reaction in the early stage is transition from the 4 S to the 20 S state. As in the absence of dipolar ions, the polymerization is enhanced by an increase in temperature; it is endothermic and therefore entropy-driven. The effect of the dipolar ions can be understood in terms of their action as salting-out agents; they increase the activity coefficient of TMV A protein, the 4 S material, and thus shift the equilibrium toward the 20 S state. The salting-out constants, K, for the reaction in 0.10 ionic strength phosphate buffer at pH 6.7 was found by the light scattering method to be 1.6 for glycine, 2.5 for glycylglycine, and 2.5 for glycylglycylglycine. A value of 2.7 was obtained by the ultracentrifugation method for glycylglycine in phosphate buffer at 0.1 ionic strength and pH 6.8 at 10 degrees C. For both glycine and glycylglycine, K increases when the ionic strength of the phosphate buffer is decreased. This result suggests that electrolytes decrease the activity coefficient of the dipolar ions, a salting-in phenomenon. However, the salting-in constants evaluated from these results are substantially higher than those previously determined by solubility measurements. The effect of glycine and glycylglycine on polymerization was studied at pH values between 6.2 and 6.8. The effectiveness of both dipolar ions is approximately 50% greater at pH 6.8 than at pH 6.2. The variation of the extent of polymerization with pH in the presence of the dipolar ions is consistent with the interpretation that approximately one hydrogen ion is bound for half of the polypeptide units in the polymerized A protein.

  13. Towards large and powerful radio frequency driven negative ion sources for fusion

    Science.gov (United States)

    Heinemann, B.; Fantz, U.; Kraus, W.; Schiesko, L.; Wimmer, C.; Wünderlich, D.; Bonomo, F.; Fröschle, M.; Nocentini, R.; Riedl, R.

    2017-01-01

    The ITER neutral beam system will be equipped with radio-frequency (RF) negative ion sources, based on the IPP Garching prototype source design. Up to 100 kW at 1 MHz is coupled to the RF driver, out of which the plasma expands into the main source chamber. Compared to arc driven sources, RF sources are maintenance free and without evaporation of tungsten. The modularity of the driver concept permits to supply large source volumes. The prototype source (one driver) demonstrated operation in hydrogen and deuterium up to one hour with ITER relevant parameters. The ELISE test facility is operating with a source of half the ITER size (four drivers) in order to validate the modular source concept and to gain early operational experience at ITER relevant dimensions. A large variety of diagnostics allows improving the understanding of the relevant physics and its link to the source performance. Most of the negative ions are produced on a caesiated surface by conversion of hydrogen atoms. Cs conditioning and distribution have been optimized in order to achieve high ion currents which are stable in time. A magnetic filter field is needed to reduce the electron temperature and co-extracted electron current. The influence of different field topologies and strengths on the source performance, plasma and beam properties is being investigated. The results achieved in short pulse operation are close to or even exceed the ITER requirements with respect to the extracted ion currents. However, the extracted negative ion current for long pulse operation (up to 1 h) is limited by the increase of the co-extracted electron current, especially in deuterium operation.

  14. Influence of resonant magnetic perturbations on transient heat load deposition and fast ion losses

    Energy Technology Data Exchange (ETDEWEB)

    Rack, Michael Thomas

    2014-07-11

    Thermonuclear fusion is the energy conversion process which keeps the sun shining. For the last six decades, researchers have been investigating the physics involved in order to enable the usage of this energy supply on Earth. The most promising candidates for fusion power plants are based on magnetic confinement of plasma to provide the ideal conditions for efficient thermonuclear fusion in well controlled surroundings. One important aspect is the control of instabilities that occur in the edge region of the plasma and lead to an ejection of huge amounts of energy. Magnetic perturbation fields which are resonant in the plasma edge are found to modify the plasma favourably and reduce the impact of these instabilities. This dissertation focuses on the effects of resonant magnetic perturbation fields on the ejected energy as well as on the drawbacks of these perturbation fields. The transient energy ejection which is triggered by the instabilities causes extreme heat loads on the wall components in fusion devices. Therefore, it is crucial to understand how resonant magnetic perturbation fields affect the heat load deposition. Furthermore, the impact of resonant magnetic perturbation fields on the confinement of fast ions is an important aspect as fast ions are still required to be well confined in order to avoid additional wall loads and increase the fusion efficiency. Recent upgrades on the Joint European Torus allow for a detailed study of the heat load deposition profiles caused by transient events. Throughout this work, the new features are used for the study of the modifications of the transient heat load depositions that occur if resonant magnetic perturbation fields are applied. This leads to a further understanding of the processes involved during the plasma edge instabilities. Additionally, an alternative method using lower hybrid waves for applying resonant magnetic perturbations is investigated. Furthermore, a new diagnostic, capable of detecting fast ion

  15. Fast dose analysis of movement effects during treatments with scanned proton and carbon-ion beams

    Science.gov (United States)

    Vignati, A.; Varasteh Anvar, M.; Giordanengo, S.; Monaco, V.; Attili, A.; Donetti, M.; Marchetto, F.; Mas Milian, F.; Ciocca, M.; Russo, G.; Sacchi, R.; Cirio, R.

    2017-01-01

    Charged particle therapy delivered using scanned pencil beams shows the potential to produce better dose conformity than conventional radiotherapy, although the dose distributions are more sensitive to anatomical changes and patient motion. Therefore, the introduction of engines to monitor the dose as it is being delivered is highly desirable, in order to enhance the development of adaptive treatment techniques in hadrontherapy. A tool for fast dose distributions analysis is presented, which integrates on GPU a Fast Forward Planning, a Fast Image Deformation algorithm, a fast computation of Gamma-Index and Dose-Volume Histogram. The tool is being interfaced with the Dose Delivery System and the Optical Tracking System of a synchrotron-based facility to investigate the feasibility to quantify, spill by spill, the effects of organ movements on dose distributions during treatment deliveries with protons and carbon-ions. The dose calculation and comparison times for a patient treated with protons on a 61.3 cm3 planning target volume, a CT matrix of 512x512x125 voxels, and a computation matrix of 170x170x125 voxels are within 1 s per spill. In terms of accuracy, the absolute dose differences compared with benchmarked Treatment Planning System results are negligible (<10-4 Gy).

  16. Phase-space dependent critical gradient behavior of fast-ion transport due to Alfvén eigenmodes

    Science.gov (United States)

    Collins, C. S.; Heidbrink, W. W.; Podestà, M.; White, R. B.; Kramer, G. J.; Pace, D. C.; Petty, C. C.; Stagner, L.; Van Zeeland, M. A.; Zhu, Y. B.; The DIII-D Team

    2017-08-01

    Experiments in the DIII-D tokamak show that many overlapping small-amplitude Alfvén eigenmodes (AEs) cause fast-ion transport to sharply increase above a critical threshold in beam power, leading to fast-ion density profile resilience and reduced fusion performance. The threshold is above the AE linear stability limit and varies between diagnostics that are sensitive to different parts of fast-ion phase-space. Comparison with theoretical analysis using the nova and orbit codes shows that, for the neutral particle diagnostic, the threshold corresponds to the onset of stochastic particle orbits due to wave-particle resonances with AEs in the measured region of phase space. The bulk fast-ion distribution and instability behavior was manipulated through variations in beam deposition geometry, and no significant differences in the onset threshold outside of measurement uncertainties were found, in agreement with the theoretical stochastic threshold analysis. Simulations using the ‘kick model’ produce beam ion density gradients consistent with the empirically measured radial critical gradient and highlight the importance of including the energy and pitch dependence of the fast-ion distribution function in critical gradient models. The addition of electron cyclotron heating changes the types of AEs present in the experiment, comparatively increasing the measured fast-ion density and radial gradient. These studies provide the basis for understanding how to avoid AE transport that can undesirably redistribute current and cause fast-ion losses, and the measurements are being used to validate AE-induced transport models that use the critical gradient paradigm, giving greater confidence when applied to ITER.

  17. ITER fast ion collective Thomson scattering. Conceptual design of 60 GHz system

    DEFF Research Database (Denmark)

    Meo, Fernando; Bindslev, Henrik; Korsholm, Søren Bang

    The collective Thomson scattering diagnostic for ITER at the 60 GHz range is capable of measuring the fast ion distribution parallel and perpendicular to the magnetic field at different radial locations simultaneously. The design is robust technologically with no moveable components near the plasma...... describes the two systems and their main components. Section 3 clarifies the impact of design parameters such as beam widths and scattering angle on the CTS measurements. With this in hand, the ITER measurement requirements are translated into constraints on the CTS system designs. An important result...

  18. Recent Experiment Results on Fast Ion Instability at 2.5 GeV PLS

    CERN Document Server

    Kim Eun San; Hukuma, Hitoshi; Ikeda, Hitomi; Park, Chong-Do; Park, Sung-Ju; Soo Ko In; Yun Huang Jung

    2005-01-01

    We present recent experiment results on the fast ion instability that were performed at the PLS storage ring. With higher vacuum pressures of three orders of magnitude than nominal one by He gas injection into the ring, increases of a factor of around three in the vertical beam size were observed by interferometer system. From the various measurement results, we estimated growth times for the instability as a funcion of vacuum pressure and beam current. We also compared the results with those of the computer simulations and analytical calculations.

  19. Wave packet evolution approach to ionization of hydrogen molecular ion by fast electrons

    CERN Document Server

    Serov, V V; Joulakian, B B; Vinitsky, S I; Serov, Vladislav V.; Derbov, Vladimir L.; Joulakian, Boghos B.; Vinitsky, Sergue I.

    2000-01-01

    The multiply differential cross section of the ionization of hydrogen molecular ion by fast electron impact is calculated by a direct approach, which involves the reduction of the initial 6D Schr\\"{o}dinger equation to a 3D evolution problem followed by the modeling of the wave packet dynamics. This approach avoids the use of stationary Coulomb two-centre functions of the continuous spectrum of the ejected electron which demands cumbersome calculations. The results obtained, after verification of the procedure in the case atomic hydrogen, reveal interesting mechanisms in the case of small scattering angles.

  20. Fast Ion Induced Shearing of 2D Alfven Eigenmodes Measured by Electron Cyclotron Emission Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, Ben [University of California, Davis; Classen, I.G.J. [FOM Institute for Plasma Physics Rijnhuizen, Nieuwegein, The Netherlands; Domier, C. W. [University of California, Davis; Heidbrink, W. [University of California, Irvine; Luhmann, N.C. [University of California, Davis; Nazikian, Raffi [Princeton Plasma Physics Laboratory (PPPL); Park, H.K. [Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea; Spong, Donald A [ORNL; Van Zeeland, Michael [General Atomics

    2011-01-01

    Two-dimensional images of electron temperature perturbations are obtained with electron cyclotron emission imaging (ECEI) on the DIII-D tokamak and compared to Alfven eigenmode structures obtained by numerical modeling using both ideal MHD and hybrid MHD-gyrofluid codes. While many features of the observations are found to be in excellent agreement with simulations using an ideal MHD code (NOVA), other characteristics distinctly reveal the influence of fast ions on the mode structures. These features are found to be well described by the nonperturbative hybrid MHD-gyrofluid model TAEFL.

  1. Degradation of Methylammonium Lead Iodide Perovskite Structures through Light and Electron Beam Driven Ion Migration.

    Science.gov (United States)

    Yuan, Haifeng; Debroye, Elke; Janssen, Kris; Naiki, Hiroyuki; Steuwe, Christian; Lu, Gang; Moris, Michèle; Orgiu, Emanuele; Uji-I, Hiroshi; De Schryver, Frans; Samorì, Paolo; Hofkens, Johan; Roeffaers, Maarten

    2016-02-04

    Organometal halide perovskites show promising features for cost-effective application in photovoltaics. The material instability remains a major obstacle to broad application because of the poorly understood degradation pathways. Here, we apply simultaneous luminescence and electron microscopy on perovskites for the first time, allowing us to monitor in situ morphology evolution and optical properties upon perovskite degradation. Interestingly, morphology, photoluminescence (PL), and cathodoluminescence of perovskite samples evolve differently upon degradation driven by electron beam (e-beam) or by light. A transversal electric current generated by a scanning electron beam leads to dramatic changes in PL and tunes the energy band gaps continuously alongside film thinning. In contrast, light-induced degradation results in material decomposition to scattered particles and shows little PL spectral shifts. The differences in degradation can be ascribed to different electric currents that drive ion migration. Moreover, solution-processed perovskite cuboids show heterogeneity in stability which is likely related to crystallinity and morphology. Our results reveal the essential role of ion migration in perovskite degradation and provide potential avenues to rationally enhance the stability of perovskite materials by reducing ion migration while improving morphology and crystallinity. It is worth noting that even moderate e-beam currents (86 pA) and acceleration voltages (10 kV) readily induce significant perovskite degradation and alter their optical properties. Therefore, attention has to be paid while characterizing such materials using scanning electron microscopy or transmission electron microscopy techniques.

  2. Model for collisional fast ion diffusion into Tokamak Fusion Test Reactor loss cone

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.S. [New York Univ., NY (United States). Courant Inst. of Mathematical Sciences]|[Korea Advanced Inst. of Science and Technology, Seoul (Korea, Republic of); Zweben, S.J.; Schivell, J.; Budny, R.; Scott, S. [Princeton Univ., NJ (United States). Plasma Physics Lab.

    1994-08-01

    An analytic model is developed to estimate the classical pitch angle scattering loss of energetic fusion product ions into prompt loss orbits in a tokamak geometry. The result is applied to alpha particles produced by deutrium-tritium fusion reactions in a plasma condition relevant to Tokamak Fusion Test Reactor (TFTR). A poloidal angular distribution of collisional fast ion loss at the first wall is obtained and the numerical result from the TRANSP code is discussed. The present model includes the effect that the prompt loss boundary moves away from the slowing-down path due to reduction in banana thickness, which enables us to understand, for the first time. the dependence of the collisional loss rate on Z{sub eff}.

  3. Hole boring in a DT Pellet and Fast-Ion Ignition with Ultraintense Laser Pulses.

    Science.gov (United States)

    Naumova, N; Schlegel, T; Tikhonchuk, V T; Labaune, C; Sokolov, I V; Mourou, G

    2009-01-16

    Recently achieved high intensities of short laser pulses open new prospects in their application to hole boring in inhomogeneous overdense plasmas and for ignition in precompressed DT fusion targets. A simple analytical model and numerical simulations demonstrate that pulses with intensities exceeding 10;{22} W/cm;{2} may penetrate deeply into the plasma as a result of efficient ponderomotive acceleration of ions in the forward direction. The penetration depth as big as hundreds of microns depends on the laser fluence, which has to exceed a few tens of GJ/cm;{2}. The fast ions, accelerated at the bottom of the channel with an efficiency of more than 20%, show a high directionality and may heat the precompressed target core to fusion conditions.

  4. Fast electron generation by Coulomb scattering on spatially correlated ions in a strong laser field

    CERN Document Server

    Bauch, S

    2009-01-01

    Electrons colliding with spatially fixed ions in strong laser fields are investigated by solving the time-dependent Schr\\"odinger equation. Considering first simple one-dimensional model systems, the mechanisms and energy spectra of fast electrons are analyzed, starting from collisions on a single ion. By using these electrons as projectiles for a second and third collision, the maximum possible energy obtained can be significantly increased. We then generalize the analysis to 2D systems where additional angular degrees of freedom lead to a drastic loss of efficiency. This problem can be overcome by introducing external confinements, which allow to focus the electrons and increase the intensity of high-energy electrons.

  5. Fast removal of heavy metal ions and phytic acids from water using new modified chelating fiber

    Institute of Scientific and Technical Information of China (English)

    Li Xu; Jin Nan Wang; Ying Meng; Ai Min Li

    2012-01-01

    The graft copolymerization of acrylic acid (AA) onto polyethylene glycol terephthalate (PET) fiber initiated by benzoy peroxide (BPO) was carried out in heterogeneous media.Moreover,modification of the grafted PET fiber (PET-AA) was done by changing the carboxyl group into acylamino group through the reaction with dimethylamine.The modified chelating fiber (NDWJN 1) was characterized using elementary analysis,SEM and FT-IR spectroscopy.Adsorption kinetic curves indicated that NDWJN1 could fast remove heavy metal ions and phytic acids from water effectively.Furthermore,batch kinetic studies indicated that heavy metal ions adsorbed to NDWJN1 could be fitted well by both pseudo-first-order and pseudo-second-order adsorption equations,but the intra-particle diffusion plaved a dominant role in the adsorption of phvtic acids.

  6. Ion temperature anisotropy effects on threshold conditions of a shear-modified current driven electrostatic ion-acoustic instability in the topside auroral ionosphere

    OpenAIRE

    Perron, P. J. G.; J.-M. A. Noël; Kabin, K.; St-Maurice, J.-P.

    2013-01-01

    Temperature anisotropies may be encountered in space plasmas when there is a preferred direction, for instance, a strong magnetic or electric field. In this paper, we study how ion temperature anisotropy can affect the threshold conditions of a shear-modified current driven electrostatic ion-acoustic (CDEIA) instability. In particular, this communication focuses on instabilities in the context of topside auroral F-region situations and in the limit where finite Larmor radius...

  7. 2D profile of poloidal magnetic field diagnosed by a laser-driven ion-beam trace probe (LITP)

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaoyi; Xiao, Chijie, E-mail: cjxiao@pku.edu.cn; Chen, Yihang; Xu, Tianchao; Lin, Chen [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wang, Long [Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190 (China); Xu, Min [Center for Fusion Science of Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Yu, Yi [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China)

    2016-11-15

    Based on large energy spread of laser-driven ion beam (LIB), a new method, the Laser-driven Ion-beam Trace Probe (LITP), was suggested recently to diagnose the poloidal magnetic field (B{sub p}) and radial electric field (E{sub r}) in toroidal devices. Based on another property of LIB, a wide angular distribution, here we suggested that LITP could be extended to get 2D B{sub p} profile or 1D profile of both poloidal and radial magnetic fields at the same time. In this paper, we show the basic principle, some preliminary simulation results, and experimental preparation to test the basic principle of LITP.

  8. 2D profile of poloidal magnetic field diagnosed by a laser-driven ion-beam trace probe (LITP)

    Science.gov (United States)

    Yang, Xiaoyi; Xiao, Chijie; Chen, Yihang; Xu, Tianchao; Lin, Chen; Wang, Long; Xu, Min; Yu, Yi

    2016-11-01

    Based on large energy spread of laser-driven ion beam (LIB), a new method, the Laser-driven Ion-beam Trace Probe (LITP), was suggested recently to diagnose the poloidal magnetic field (Bp) and radial electric field (Er) in toroidal devices. Based on another property of LIB, a wide angular distribution, here we suggested that LITP could be extended to get 2D Bp profile or 1D profile of both poloidal and radial magnetic fields at the same time. In this paper, we show the basic principle, some preliminary simulation results, and experimental preparation to test the basic principle of LITP.

  9. Ionization and bound-state relativistic quantum dynamics in laser-driven multiply charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Hetzheim, Henrik

    2009-01-14

    The interaction of ultra-strong laser fields with multiply charged hydrogen-like ions can be distinguished in an ionization and a bound dynamics regime. Both are investigated by means of numerically solving the Dirac equation in two dimensions and by a classical relativistic Monte-Carlo simulation. For a better understanding of highly nonlinear physical processes the development of a well characterized ultra-intense relativistic laser field strength has been driven forward, capable of studying e.g. the magnetic field effects of the laser resulting in an additional electron motion in the laser propagation direction. A novel method to sensitively measure these ultra-strong laser intensities is developed and employed from the optical via the UV towards the XUV frequency regime. In the bound dynamics field, the determination of multiphoton transition matrixelements has been investigated between different bound states via Rabi oscillations. (orig.)

  10. Bifurcation Theory of the Transition to Collisionless Ion-temperature-gradient-driven Plasma Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Kolesnikov, R.A.; Krommes, J.A.

    2005-09-22

    The collisionless limit of the transition to ion-temperature-gradient-driven plasma turbulence is considered with a dynamical-systems approach. The importance of systematic analysis for understanding the differences in the bifurcations and dynamics of linearly damped and undamped systems is emphasized. A model with ten degrees of freedom is studied as a concrete example. A four-dimensional center manifold (CM) is analyzed, and fixed points of its dynamics are identified and used to predict a ''Dimits shift'' of the threshold for turbulence due to the excitation of zonal flows. The exact value of that shift in terms of physical parameters is established for the model; the effects of higher-order truncations on the dynamics are noted. Multiple-scale analysis of the CM equations is used to discuss possible effects of modulational instability on scenarios for the transition to turbulence in both collisional and collisionless cases.

  11. A simple model for cavity-enhanced laser-driven ion acceleration from thin foil targets

    CERN Document Server

    Rączka, Piotr

    2012-01-01

    A scenario for the laser-driven ion acceleration off a solid target is considered, where the reflected laser pulse is redirected towards the target by reflection at the inner cavity wall, thus recycling to some extent the incident laser energy. This scenario is discussed in the context of sub-wavelength foil acceleration in the radiation pressure regime, when plasma dynamics is known to be reasonably well described by the laser-sail model. A semi-analytic extension of the 1D laser-sail model is constructed, which takes into account the effect of reflections at the inner cavity wall. The effect of cavity reflections on sub-wavelength foil acceleration is then illustrated with two concrete examples of intense laser pulses of picosecond and femtosecond duration.

  12. Neutron Signatures of Non-Thermal Ion Distributions in Z-Pinch Driven ICF Plasmas

    Science.gov (United States)

    Knapp, Patrick; Jennings, Christopher; Sinars, Daniel

    2012-10-01

    In preparation for upcoming ICF experiments on the 26 MA Z machine (e.g., D2 gas puff, MagLIF [1]), we are studying the neutron energy spectra produced by magnetically-driven loads beyond the archetypal single temperature, uniform plasma. Z-pinch sources frequently exhibit evidence of unusual neutron spectra [2], which can be attributed to three-dimensional turbulent motion, high-energy beams, and other phenomena leading to non-Maxwellian ion distributions. Understanding the nature of our plasma neutron sources is critical for understanding how they scale with increasing current. We will show Monte Carlo and analytic calculations for plausible scenarios and discuss the corresponding signatures for the existing set of time-of-flight diagnostics on Z.[4pt] [1] S. A. Slutz et al. Phys. Plasmas 17, 056303 (2010)[0pt] [2] V.V. Vikhrev and V.D. Korolev, Plasma Dynamics, Vol. 33, No. 5 (2007)

  13. Ways to improve the efficiency and reliability of radio frequency driven negative ion sources for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, W., E-mail: kraus@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik (IPP), Boltzmannstr. 2, 85748 Garching (Germany); Briefi, S.; Fantz, U. [Max-Planck-Institut für Plasmaphysik (IPP), Boltzmannstr. 2, 85748 Garching (Germany); AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany); Gutmann, P.; Doerfler, J. [AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany)

    2014-02-15

    Large RF driven negative hydrogen ion sources are being developed at IPP Garching for the future neutral beam injection system of ITER. The overall power efficiency of these sources is low, because for the RF power supply self-excited generators are utilized and the plasma is generated in small cylindrical sources (“drivers”) and expands into the source main volume. At IPP experiments to reduce the primary power and the RF power required for the plasma production are performed in two ways: The oscillator generator of the prototype source has been replaced by a transistorized RF transmitter and two alternative driver concepts, a spiral coil, in which the field is concentrated by ferrites, which omits the losses by plasma expansion and a helicon source are being tested.

  14. Fast rotating group of stars observed in Gaia TGAS: a signature driven by the Perseus arm?

    CERN Document Server

    Hunt, Jason A S; Monari, Giacomo; Grand, Robert J J; Famaey, Benoit; Siebert, Arnaud

    2016-01-01

    We report on the detection of a small overdensity of stars in velocity space with systematically higher Galactocentric rotation velocity than the Sun by about 20 km s$^{-1}$ in the $Gaia$ Data Release 1 Tycho-Gaia astrometric solution (TGAS) data. We find the fast rotating group of stars more clearly outside of the Solar radius, compared to inside of the Solar radius. In addition, the velocity of the fast rotating group is independent of the Galactocentric distance up to $R-R_{\\odot}\\sim 0.6$ kpc. Comparing with numerical models, we discuss that a possible cause of this feature is the co-rotation resonance of the Perseus spiral arm, where the stars in peri-centre phase in the trailing side of the Perseus spiral arm experience an extended period of acceleration owing to the torque from the Perseus arm.

  15. Fast Optically Driven Spin Qubit Gates in an InAs Quantum Dot

    Science.gov (United States)

    2010-01-01

    epitaxy. The sample is placed in a magneto cryostat to enable operating temperatures of approximately 5 K. Optical excitation through 1μm diameter...Reinecke and D. Gammon, “ Optical Spin Initialization and Nondestructive Measurement in a Quantum Dot Molecule ”, Phys. Rev. Lett., 101, 236804 (2008) 12...Theory of Fast Optical Spin Rotation in a Quantum Dot Based on Geometric Phases and Trapped States”, Phys. Rev. Lett., 99, 217401 (2007) 16. Y

  16. The ELIMED transport and dosimetry beamline for laser-driven ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Romano, F., E-mail: francesco.romano@lns.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Schillaci, F.; Cirrone, G.A.P.; Cuttone, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Scuderi, V. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); ELI-Beamlines Project, Institute of Physics ASCR, v.v.i. (FZU), 182 21 Prague (Czech Republic); Allegra, L.; Amato, A.; Amico, A.; Candiano, G.; De Luca, G.; Gallo, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Giordanengo, S.; Guarachi, L. Fanola [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Via P. Giuria 1, Torino (Italy); Universita' di Torino, Dipartimento di Fisica, Via P. Giuria 1, Torino (Italy); Korn, G. [ELI-Beamlines Project, Institute of Physics ASCR, v.v.i. (FZU), 182 21 Prague (Czech Republic); Larosa, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Leanza, R. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Universita' di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Manna, R.; Marchese, V. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Marchetto, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Via P. Giuria 1, Torino (Italy); Margarone, D. [ELI-Beamlines Project, Institute of Physics ASCR, v.v.i. (FZU), 182 21 Prague (Czech Republic); and others

    2016-09-01

    A growing interest of the scientific community towards multidisciplinary applications of laser-driven beams has led to the development of several projects aiming to demonstrate the possible use of these beams for therapeutic purposes. Nevertheless, laser-accelerated particles differ from the conventional beams typically used for multiscipilinary and medical applications, due to the wide energy spread, the angular divergence and the extremely intense pulses. The peculiarities of optically accelerated beams led to develop new strategies and advanced techniques for transport, diagnostics and dosimetry of the accelerated particles. In this framework, the realization of the ELIMED (ELI-Beamlines MEDical and multidisciplinary applications) beamline, developed by INFN-LNS (Catania, Italy) and that will be installed in 2017 as a part of the ELIMAIA beamline at the ELI-Beamlines (Extreme Light Infrastructure Beamlines) facility in Prague, has the aim to investigate the feasibility of using laser-driven ion beams for multidisciplinary applications. In this contribution, an overview of the beamline along with a detailed description of the main transport elements as well as the detectors composing the final section of the beamline will be presented.

  17. Geometric stabilization of the electrostatic ion-temperature-gradient driven instability. I. Nearly axisymmetric systems

    Science.gov (United States)

    Zocco, A.; Plunk, G. G.; Xanthopoulos, P.; Helander, P.

    2016-08-01

    The effects of a non-axisymmetric (3D) equilibrium magnetic field on the linear ion-temperature-gradient (ITG) driven mode are investigated. We consider the strongly driven, toroidal branch of the instability in a global (on the magnetic surface) setting. Previous studies have focused on particular features of non-axisymmetric systems, such as strong local shear or magnetic ripple, that introduce inhomogeneity in the coordinate along the magnetic field. In contrast, here we include non-axisymmetry explicitly via the dependence of the magnetic drift on the field line label α, i.e., across the magnetic field, but within the magnetic flux surface. We consider the limit where this variation occurs on a scale much larger than that of the ITG mode, and also the case where these scales are similar. Close to axisymmetry, we find that an averaging effect of the magnetic drift on the flux surface causes global (on the surface) stabilization, as compared to the most unstable local mode. In the absence of scale separation, we find destabilization is also possible, but only if a particular resonance occurs between the magnetic drift and the mode, and finite Larmor radius effects are neglected. We discuss the relative importance of surface global effects and known radially global effects.

  18. Energetic Particle Diagnostics for Transport Analysis 3.Escaping Fast Ion Diagnostics for the Fast Particle Transport Analysis

    Science.gov (United States)

    Isobe, Mitsutaka; Shinohara, Kouji

    Escaping energetic ion diagnostics in magnetically confined plasma experiments are described in this lecture note. Experimental results from escaping energetic ion diagnostics in TFTR, JFT-2M, CHS and W7-AS are shown. In addition to mechanism of energetic ion loss from a viewpoint of particle orbit, effect of MHD activity on energetic particle transport is reviewed.

  19. Characterization of scintillator materials for fast-ion loss detectors in nuclear fusion reactors

    Science.gov (United States)

    Jiménez-Ramos, M. C.; García López, J.; García-Muñoz, M.; Rodríguez-Ramos, M.; Carmona Gázquez, M.; Zurro, B.

    2014-08-01

    In fusion plasma reactors, fast ion generated by heating systems and fusion born particles must be well confined. The presence of magnetohydrodynamic (MHD) instabilities can lead to a significant loss of these ions, which may reduce drastically the heating efficiency and may cause damage to plasma facing components in the vacuum vessel. In order to understand the physics underlying the fast ion loss mechanism, scintillator based detectors have been installed in several fusion devices. In this work we present the absolute photon yield and its degradation with ion fluence in terms of the number of photons emitted per incident ion of several scintillators thin coatings: SrGa2S4:Eu2+ (TG-Green), Y3Al5O12:Ce3+ (P46) and Y2O3:Eu3+ (P56) when irradiated with light ions of different masses (deuterium ions, protons and α-particles) at energies between approximately 575 keV and 3 MeV. The photon yield will be discussed in terms of the energy deposited by the particles into the scintillator. For that, the actual composition and thickness of the thin layers were determined by Rutherford Backscattering Spectrometry (RBS). A collimator with 1 mm of diameter, which defines the beam size for the experiments, placed at the entrance of the chamber. An electrically isolated sample holder biased to +300 V to collect the secondary electrons, connected to a digital current integrator (model 439 by Ortec) to measure the incident beam current. A home made device has been used to store the real-time evolution of the beam current in a computer file allowing the correction of the IL yields due to the current fluctuations. The target holder is a rectangle of 150 × 112 mm2 and can be tilted. The X and Y movements are controlled through stepping motors, which permits a fine control of the beam spot positioning as well as the study of several samples without venting the chamber. A silica optical fiber of 1 mm diameter fixed to the vacuum chamber, which collects the light from the scintillators

  20. Characteristics of a 13.56 MHz radiofrequency-driven multicusp ion source

    Energy Technology Data Exchange (ETDEWEB)

    Boonyawan, D; Chiraphatpimol, N; Vilaithong, T [Fast Neutron Research Facility, Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2002-11-01

    The characteristics of a radiofrequency (rf)-driven multicusp ion source are investigated. The ion source is an Nd-Fe-B magnetic multicusp type operated at 13.56 MHz with an internal quartz covered antenna. The source has been diagnosed by an rf-compensated Langmuir probe for uniformity, density and electron temperature. A retarding field energy analyser, and a multi-wire beam profile monitor and quadrupole magnet system have been used for beam energy spread and emittance measurements. Experiments were performed with argon gas and rf power up to 500 W. A plasma density of up to 1.5x10{sup 18} m{sup -3} was obtained. The rms beam emittance is found to be about 32{+-}4 mm mrad, and the energy spread of the argon beam is around 3.1{+-}0.5 eV at 3 kV extraction. The rf coupling to the extracting voltage could be suppressed by a 1.2 mH rf choke, which results in the reduction of the axial energy spread in the extracted beam.

  1. Characteristics of a 13.56 MHz radiofrequency-driven multicusp ion source

    Science.gov (United States)

    Boonyawan, D.; Chiraphatpimol, N.; Vilaithong, T.

    2002-11-01

    The characteristics of a radiofrequency (rf)-driven multicusp ion source are investigated. The ion source is an Nd-Fe-B magnetic multicusp type operated at 13.56 MHz with an internal quartz covered antenna. The source has been diagnosed by an rf-compensated Langmuir probe for uniformity, density and electron temperature. A retarding field energy analyser, and a multi-wire beam profile monitor and quadrupole magnet system have been used for beam energy spread and emittance measurements. Experiments were performed with argon gas and rf power up to 500 W. A plasma density of up to 1.5×1018 m-3 was obtained. The rms beam emittance is found to be about 32+/-4 mm mrad, and the energy spread of the argon beam is around 3.1+/-0.5 eV at 3 kV extraction. The rf coupling to the extracting voltage could be suppressed by a 1.2 mH rf choke, which results in the reduction of the axial energy spread in the extracted beam.

  2. Ion-neutral friction and accretion-driven turbulence in self-gravitating filaments

    CERN Document Server

    Hennebelle, Patrick

    2013-01-01

    Recent Herschel observations have confirmed that filaments are ubiquitous in molecular clouds and suggest that irrespectively of the column density, there is a characteristic width of about 0.1 pc whose physical origin remains unclear. We develop an analytical model that can be applied to self-gravitating accreting filaments. It is based on one hand on the virial equilibrium of the central part of the filament and on the other hand on energy balance between the turbulence driven by accretion onto the filament and dissipation. We consider two dissipation mechanisms the turbulent cascade and the ion-neutral friction. Our model predicts that the width of the filament inner part is almost independent of the column density and leads to values comparable to what is inferred observationally if dissipation is due to ion-neutral friction. On the contrary turbulent dissipation leads to a structure that is bigger and depends significantly on the column density. Our model provides a reasonable physical explanation which ...

  3. Target design for the cylindrical compression of matter driven by heavy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Piriz, A.R. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)]. E-mail: roberto.piriz@uclm.es; Temporal, M. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Lopez Cela, J.J. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Grandjouan, N. [LULI, UMR 7605, Ecole Polytechnique-CNRS-CEA-Universite Paris VI, Palaiseau (France); Tahir, N.A. [GSI Darmstadt, Plankstrasse 1, 64291 Darmstadt (Germany); Serna Moreno, M.C. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Portugues, R.F. [E. T. S. I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Hoffmann, D.H.H. [GSI Darmstadt, Plankstrasse 1, 64291 Darmstadt (Germany)

    2005-05-21

    The compression of a cylindrical sample of hydrogen contained in a hollow shell of Pb or Au has been analyzed in the framework of the experiments to be performed in the heavy ion synchrotron SIS100 to be constructed at the Gesellschaft fuer Schwerionenforschung (GSI) Darmstadt. The target implosion is driven by an intense beam of heavy ions with a ring-shaped focal spot. We report the results of a parametric study of the final state of the compressed hydrogen in terms of the target and beam parameters. We consider the generation of the annular heated region by means of a radio-frequency wobbler that rotates the beam at extremely high frequencies in order to accommodate symmetry constraints. We have also studied the hydrogen conditions that can be achieved with a non-rotating beam with Gaussian focal spot and the possibility to use a beam stopper as an alternative way to avoid the direct heating of the sample. Finally, we report the analysis of the hydrodynamic instabilities that affect the implosion and the mitigating effects of the elastoplastic properties of the shell.

  4. Fast selective detection of polar brominated disinfection byproducts in drinking water using precursor ion scans.

    Science.gov (United States)

    Zhang, Xiangru; Talley, Jeffrey W; Boggess, Bill; Ding, Guoyu; Birdsell, Dennis

    2008-09-01

    Brominated disinfection byproducts (DBPs), formed from the reaction of disinfectant(s) with natural organic matter and bromide in raw water, are generally more cytotoxic and genotoxic than their chlorinated analogues. Brominated DBPs have been intensively studied over the past 35 years, yet only a fraction of the total organic bromine formed during disinfection has been identified. A significant portion of the unaccounted total organic bromine may be attributed to polar/highly polar brominated DBPs. In this work, a method for fast selective detection of polar/ highly polar brominated DBPs in drinking water was developed using negative ion electrospray ionization-triple quadrupole mass spectrometry (ESI-tqMS) by setting precursor ion scans of m/z 79 and 81. This method was conducted without liquid chromatography separation. The results demonstrate that the ESI-tqMS precursor ion scan is an effective tool for the selective detection of electrospray ionizable bromine-containing compounds in a complex mixture. Many polar/ highly polar bromine-containing DBPs were tentatively found in two drinking water samples, and some of them may be new brominated DBPs that have not been previously reported. This method was also extended for the selective detection of polar bromine-containing compounds/contaminants in groundwater, surface water and wastewater.

  5. Fast Beam-ion Instabilities in CLIC Main Linac Vacuum Specifications

    CERN Document Server

    Oeftiger, Adrian

    2011-01-01

    Specifications for the vacuum pressure in the CLIC electron Main Linac are determined by the onset of the fast beam-ion instability (FBII). When the electron beam is accelerated in the Main Linac, it ionizes the residual gas in the chamber through scattering ionization. If the density of ions around the beam exceeds a certain threshold, a resonant motion between the electron beam and the ions can be excited. A two-stream instability appears and as a result the beam acquires a coherent motion, which can quickly lead to beam quality degradation or even complete loss. Thus, the vacuum pressure must be kept below this threshold to prevent the excitation of FBII. The CLIC Main Linac poses an additional challenge with respect to previous FBII situations, because the gas ionization does not solely occur via scattering. The submicrometric beam sizes lead to extremely high electric fields around the beam and therefore result in field ionization beyond a certain threshold. The residual gas in the corresponding volume a...

  6. On The Anomalous Fast Ion Energy Diffusion in Toroidal Plasmas Due to Cavity Modes

    Energy Technology Data Exchange (ETDEWEB)

    N.N. Gorelenkov, N.J. Fisch and E. Fredrickson

    2010-03-09

    An enormous wave-particle diffusion coefficient along paths suitable for alpha channeling had been deduced in mode converted ion Bernstein wave experiments on Tokamak Fusion Test Reactor (TFTR) the only plausible explanation advanced for such a large diffusion coefficient was the excitation of internal cavity modes which induce particle diffusion along identical diffusion paths, but at much higher rates. Although such a mode was conjectured, it was never observed. However, recent detailed observations of high frequency compressional Alfven eigenmodes (CAEs) on the National Spherical torus Experiment (NSTX) indirectly support the existence of the related conjectured modes on TFTR. The eigenmodes responsible for the high frequency magnetic activity can be identified as CAEs through the polarization of the observed magnetic field oscillations in NSTX and through a comparison with the theoretically derived freuency dispersion relation. Here, we show how these recent observations of high frequency CAEs lend support to this explanation of the long-standing puzzle of anomalous fast ion energy diffusion on TFTR. The support of the conjecure that these internal modes could have caused the remarkable ion energy diffusion on TFTR carries significant and favorable implications for the possibilities in achieving the alpha channeling effect with small injected power in a tokamak reactor.

  7. Neutron yield when fast deuterium ions collide with strongly charged tritium-saturated dust particles

    Energy Technology Data Exchange (ETDEWEB)

    Akishev, Yu. S., E-mail: akishev@triniti.ru; Karal’nik, V. B.; Petryakov, A. V.; Starostin, A. N.; Trushkin, N. I.; Filippov, A. V. [State Research Center of Russian Federation, Troitsk Institute for Innovation and Thermonuclear Research (Russian Federation)

    2017-02-15

    The ultrahigh charging of dust particles in a plasma under exposure to an electron beam with an energy up to 25 keV and the formation of a flux of fast ions coming from the plasma and accelerating in the strong field of negatively charged particles are considered. Particles containing tritium or deuterium atoms are considered as targets. The calculated rates of thermonuclear fusion reactions in strongly charged particles under exposure to accelerated plasma ions are presented. The neutron generation rate in reactions with accelerated deuterium and tritium ions has been calculated for these targets. The neutron yield has been calculated when varying the plasma-forming gas pressure, the plasma density, the target diameter, and the beam electron current density. Deuterium and tritium-containing particles are shown to be the most promising plasmaforming gas–target material pair for the creation of a compact gas-discharge neutron source based on the ultrahigh charging of dust particles by beam electrons with an energy up to 25 keV.

  8. FAST

    DEFF Research Database (Denmark)

    Zuidmeer-Jongejan, Laurian; Fernandez-Rivas, Montserrat; Poulsen, Lars K.

    2012-01-01

    ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections with aqu......ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections...... with aqueous food extracts may be effective but has proven to be accompanied by too many anaphylactic side-effects. FAST aims to develop a safe alternative by replacing food extracts with hypoallergenic recombinant major allergens as the active ingredients of SIT. Both severe fish and peach allergy are caused...... in depth serological and cellular immune analyses will be performed, allowing identification of novel biomarkers for monitoring treatment efficacy. FAST aims at improving the quality of life of food allergic patients by providing a safe and effective treatment that will significantly lower their threshold...

  9. Alfven eigenmode stability and fast ion loss in DIII-D and ITER reversed magnetic shear plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Van Zeeland, Michael [General Atomics; Gorelenkov, Nikolai [Princeton Plasma Physics Laboratory (PPPL); Heidbrink, W. [University of California, Irvine; Kramer, G. [Princeton Plasma Physics Laboratory (PPPL); Spong, Donald A [ORNL; Austin, M. E. [University of Texas, Austin; Fisher, R K [General Atomics, San Diego; Munoz, M G [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, Garching, Germany; Gorelenkova, M. [Princeton Plasma Physics Laboratory (PPPL); Luhmann, N.C. [University of California, Davis; Murakami, Masanori [ORNL; Nazikian, Raffi [Princeton Plasma Physics Laboratory (PPPL); Park, J. M. [Oak Ridge National Laboratory (ORNL); Tobias, Ben [University of California, Davis; White, R. [Princeton Plasma Physics Laboratory (PPPL)

    2012-01-01

    Neutral beam injection into reversed-magnetic shear DIII-D plasmas produces a variety of Alfvenic activity including toroidicity-induced Alfven eigenmodes (TAEs) and reversed shear Alfven eigenmodes (RSAEs). With measured equilibrium profiles as inputs, the ideal MHD code NOVA is used to calculate eigenmodes of these plasmas. The postprocessor code NOVA-K is then used to perturbatively calculate the actual stability of the modes, including finite orbit width and finite Larmor radius effects, and reasonable agreement with the spectrum of observed modes is found. Using experimentally measured mode amplitudes, fast ion orbit following simulations have been carried out in the presence of the NOVA calculated eigenmodes and are found to reproduce the dominant energy, pitch and temporal evolution of the losses measured using a large bandwidth scintillator diagnostic. The same analysis techniques applied to a DT 8 MA ITER steady-state plasma scenario with reversed-magnetic shear and both beam ion and alpha populations show Alfven eigenmode instability. Both RSAEs and TAEs are found to be unstable with maximum growth rates occurring for toroidal mode number n = 6 and the majority of the drive coming from fast ions injected by the 1MeV negative ion beams. AE instability due to beam ion drive is confirmed by the non-perturbative code TAEFL. Initial fast ion orbit following simulations using the unstable modes with a range of amplitudes (delta B/B = 10(-5)-10(-3)) have been carried out and show negligible fast ion loss. The lack of fast ion loss is a result of loss boundaries being limited to large radii and significantly removed from the actual modes themselves.

  10. Antibodies covalently immobilized on actin filaments for fast myosin driven analyte transport.

    Directory of Open Access Journals (Sweden)

    Saroj Kumar

    Full Text Available Biosensors would benefit from further miniaturization, increased detection rate and independence from external pumps and other bulky equipment. Whereas transportation systems built around molecular motors and cytoskeletal filaments hold significant promise in the latter regard, recent proof-of-principle devices based on the microtubule-kinesin motor system have not matched the speed of existing methods. An attractive solution to overcome this limitation would be the use of myosin driven propulsion of actin filaments which offers motility one order of magnitude faster than the kinesin-microtubule system. Here, we realized a necessary requirement for the use of the actomyosin system in biosensing devices, namely covalent attachment of antibodies to actin filaments using heterobifunctional cross-linkers. We also demonstrated consistent and rapid myosin II driven transport where velocity and the fraction of motile actin filaments was negligibly affected by the presence of antibody-antigen complexes at rather high density (>20 µm(-1. The results, however, also demonstrated that it was challenging to consistently achieve high density of functional antibodies along the actin filament, and optimization of the covalent coupling procedure to increase labeling density should be a major focus for future work. Despite the remaining challenges, the reported advances are important steps towards considerably faster nanoseparation than shown for previous molecular motor based devices, and enhanced miniaturization because of high bending flexibility of actin filaments.

  11. Design of a Piezoelectric-Driven Tilt Mirror for a Fast Laser Scanner

    Science.gov (United States)

    Park, Jung-Ho; Lee, Hu-Seung; Lee, Jae-Hoon; Yun, So-Nam; Ham, Young-Bog; Yun, Dong-Won

    2012-09-01

    Recently, laser scanners have been used for laser processing such as cutting, welding, and grooving, especially in the automotive industry. The laser scanners need a high-speed driving to minimize cracks caused by thermal shock of brittle materials. Therefore, a novel laser processing system that is composed of a laser source and a piezoelectric-driven tilt mirror to control the reflection angle of the laser beam, and a stage equipped with the tilt mirror has been investigated. In this study, a piezoelectric-driven tilt mirror is designed and analyzed for scanning performance to achieve a beam spot of 30 µm, a pattern width of 1 mm, an overlap ratio of 70% of the circle area, and a scanning speed of 1 m/s. Then, structural analysis of the tilt mirror with three piezoelectric actuators is performed to determine the maximum reflection angle and resonance frequency. Finally, a prototype tilt mirror is fabricated and its basic characteristics are experimentally investigated and discussed.

  12. VORFFIP-Driven Dock: V-D2OCK, a Fast and Accurate Protein Docking Strategy

    Science.gov (United States)

    Segura, Joan; Marín-López, Manuel Alejandro; Jones, Pamela F.; Oliva, Baldo; Fernandez-Fuentes, Narcis

    2015-01-01

    The experimental determination of the structure of protein complexes cannot keep pace with the generation of interactomic data, hence resulting in an ever-expanding gap. As the structural details of protein complexes are central to a full understanding of the function and dynamics of the cell machinery, alternative strategies are needed to circumvent the bottleneck in structure determination. Computational protein docking is a valid and valuable approach to model the structure of protein complexes. In this work, we describe a novel computational strategy to predict the structure of protein complexes based on data-driven docking: VORFFIP-driven dock (V-D2OCK). This new approach makes use of our newly described method to predict functional sites in protein structures, VORFFIP, to define the region to be sampled during docking and structural clustering to reduce the number of models to be examined by users. V-D2OCK has been benchmarked using a validated and diverse set of protein complexes and compared to a state-of-art docking method. The speed and accuracy compared to contemporary tools justifies the potential use of VD2OCK for high-throughput, genome-wide, protein docking. Finally, we have developed a web interface that allows users to browser and visualize V-D2OCK predictions from the convenience of their web-browsers. PMID:25763838

  13. VORFFIP-driven dock: V-D2OCK, a fast and accurate protein docking strategy.

    Directory of Open Access Journals (Sweden)

    Joan Segura

    Full Text Available The experimental determination of the structure of protein complexes cannot keep pace with the generation of interactomic data, hence resulting in an ever-expanding gap. As the structural details of protein complexes are central to a full understanding of the function and dynamics of the cell machinery, alternative strategies are needed to circumvent the bottleneck in structure determination. Computational protein docking is a valid and valuable approach to model the structure of protein complexes. In this work, we describe a novel computational strategy to predict the structure of protein complexes based on data-driven docking: VORFFIP-driven dock (V-D2OCK. This new approach makes use of our newly described method to predict functional sites in protein structures, VORFFIP, to define the region to be sampled during docking and structural clustering to reduce the number of models to be examined by users. V-D2OCK has been benchmarked using a validated and diverse set of protein complexes and compared to a state-of-art docking method. The speed and accuracy compared to contemporary tools justifies the potential use of VD2OCK for high-throughput, genome-wide, protein docking. Finally, we have developed a web interface that allows users to browser and visualize V-D2OCK predictions from the convenience of their web-browsers.

  14. VORFFIP-driven dock: V-D2OCK, a fast and accurate protein docking strategy.

    Science.gov (United States)

    Segura, Joan; Marín-López, Manuel Alejandro; Jones, Pamela F; Oliva, Baldo; Fernandez-Fuentes, Narcis

    2015-01-01

    The experimental determination of the structure of protein complexes cannot keep pace with the generation of interactomic data, hence resulting in an ever-expanding gap. As the structural details of protein complexes are central to a full understanding of the function and dynamics of the cell machinery, alternative strategies are needed to circumvent the bottleneck in structure determination. Computational protein docking is a valid and valuable approach to model the structure of protein complexes. In this work, we describe a novel computational strategy to predict the structure of protein complexes based on data-driven docking: VORFFIP-driven dock (V-D2OCK). This new approach makes use of our newly described method to predict functional sites in protein structures, VORFFIP, to define the region to be sampled during docking and structural clustering to reduce the number of models to be examined by users. V-D2OCK has been benchmarked using a validated and diverse set of protein complexes and compared to a state-of-art docking method. The speed and accuracy compared to contemporary tools justifies the potential use of VD2OCK for high-throughput, genome-wide, protein docking. Finally, we have developed a web interface that allows users to browser and visualize V-D2OCK predictions from the convenience of their web-browsers.

  15. Fast magnetic field annihilation driven by two laser pulses in underdense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Y. J.; Kumar, D.; Weber, S.; Korn, G. [Institute of Physics of the ASCR, ELI-Beamlines, 18221 Prague (Czech Republic); Klimo, O. [Institute of Physics of the ASCR, ELI-Beamlines, 18221 Prague (Czech Republic); FNSPE, Czech Technical University in Prague, 11519 Prague (Czech Republic); Bulanov, S. V.; Esirkepov, T. Zh. [Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa-shi, Kyoto 619-0215 (Japan)

    2015-10-15

    Fast magnetic annihilation is investigated by using 2.5-dimensional particle-in-cell simulations of two parallel ultra-short petawatt laser pulses co-propagating in underdense plasma. The magnetic field generated by the laser pulses annihilates in a current sheet formed between the pulses. Magnetic field energy is converted to an inductive longitudinal electric field, which efficiently accelerates the electrons of the current sheet. This new regime of collisionless relativistic magnetic field annihilation with a timescale of tens of femtoseconds can be extended to near-critical and overdense plasma with the ultra-high intensity femtosecond laser pulses.

  16. Design and performance test of a two-axis fast steering mirror driven by piezoelectric actuators

    Science.gov (United States)

    Fang, Chu; Guo, Jin; Yang, Guo-qing; Jiang, Zhen-hua; Xu, Xin-hang; Wang, Ting-feng

    2016-09-01

    A novel design of a two-axis fast steering mirror (FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.

  17. H- ion production in electron cyclotron resonance driven multicusp volume source

    Science.gov (United States)

    Ivanov, A. A.; Rouillé, C.; Bacal, M.; Arnal, Y.; Béchu, S.; Pelletier, J.

    2004-05-01

    We have used the existing magnetic multicusp configuration of the large volume H- source Camembert III to confine the plasma created by seven elementary multidipolar electron cyclotron resonance (ECR) sources, operating at 2.45 GHz. We varied the pressure from 1 to 4 mTorr, while the total power of the microwave generator was varied between 500 W and 1 kW. We studied the plasma created by this system and measured the various plasma parameters, including the density and temperature of the negative hydrogen ions which are compared to the data obtained in a chamber with elementary ECR sources without multicusp magnetic confinement. The electron temperature is lower than that obtained with similar elementary sources in the absence of the magnetic multicusp field. We found that at pressures in the range from 2 to 4 mTorr and microwave power of up to 1 kW, the electron temperature is optimal for H- ion production (0.6-0.8 eV). This could indicate that the multicusp configuration effectively traps the fast electrons produced by the ECR discharge.

  18. Fast Acting Eddy Current Driven Valve for Massive Gas Injection on ITER

    Energy Technology Data Exchange (ETDEWEB)

    Lyttle, Mark S [ORNL; Baylor, Larry R [ORNL; Carmichael, Justin R [ORNL; Combs, Stephen Kirk [ORNL; Ericson, Milton Nance [ORNL; Ezell, N Dianne Bull [ORNL; Meitner, S. J. [Oak Ridge National Laboratory (ORNL); Rasmussen, David A [ORNL; Warmack, Robert J Bruce [ORNL; Maruyama, So [ITER Organization, Cadarache, France; Kiss, Gabor [ITER Organization, Cadarache, France

    2015-01-01

    Tokamak plasma disruptions present a significant challenge to ITER as they can result in intense heat flux, large forces from halo and eddy currents, and potential first-wall damage from the generation of multi-MeV runaway electrons. Massive gas injection (MGI) of high Z material using fast acting valves is being explored on existing tokamaks and is planned for ITER as a method to evenly distribute the thermal load of the plasma to prevent melting, control the rate of the current decay to minimize mechanical loads, and to suppress the generation of runaway electrons. A fast acting valve and accompanying power supply have been designed and first test articles produced to meet the requirements for a disruption mitigation system on ITER. The test valve incorporates a flyer plate actuator similar to designs deployed on TEXTOR, ASDEX upgrade, and JET [1 3] of a size useful for ITER with special considerations to mitigate the high mechanical forces developed during actuation due to high background magnetic fields. The valve includes a tip design and all-metal valve stem sealing for compatibility with tritium and high neutron and gamma fluxes.

  19. Fast modeling of flux trapping cascaded explosively driven magnetic flux compression generators.

    Science.gov (United States)

    Wang, Yuwei; Zhang, Jiande; Chen, Dongqun; Cao, Shengguang; Li, Da; Liu, Chebo

    2013-01-01

    To predict the performance of flux trapping cascaded flux compression generators, a calculation model based on an equivalent circuit is investigated. The system circuit is analyzed according to its operation characteristics in different steps. Flux conservation coefficients are added to the driving terms of circuit differential equations to account for intrinsic flux losses. To calculate the currents in the circuit by solving the circuit equations, a simple zero-dimensional model is used to calculate the time-varying inductance and dc resistance of the generator. Then a fast computer code is programmed based on this calculation model. As an example, a two-staged flux trapping generator is simulated by using this computer code. Good agreements are achieved by comparing the simulation results with the measurements. Furthermore, it is obvious that this fast calculation model can be easily applied to predict performances of other flux trapping cascaded flux compression generators with complex structures such as conical stator or conical armature sections and so on for design purpose.

  20. Fast ion measurements by collective Thomson scattering in TEXTOR and ASDEX Upgrade and proposal for the ITER CTS system

    DEFF Research Database (Denmark)

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

    Moving towards the era of burning fusion plasmas, a better knowledge of the physics of highly energetic particles, such as fusion born alpha particles, becomes essential. Diagnosing the fast ions in a fusion plasma is a challenging task, but the technique of collective Thomson scattering (CTS......) provides the possibility of revealing the velocity distribution of the confined fast ions along a given direction – resolved both in time and space. Recently, the ITER baseline design has been expanded to include the enabling of the front end of a fast ion CTS diagnostic system resolving dynamics...... perpendicular to the magnetic field. The feasibility study and conceptual design of this diagnostic was provided by the CTS group at Risø DTU. The development of the ITER CTS diagnostic builds on the experiences and expertise gained from the construction and current operation of the CTS diagnostic systems...

  1. Intense laser-driven ion beams in the relativistic-transparency regime: acceleration, control and applications

    Science.gov (United States)

    Fernandez, Juan C.

    2016-10-01

    Laser-plasma interactions in the novel regime of relativistically-induced transparency have been harnessed to generate efficiently intense ion beams with average energies exceeding 10 MeV/nucleon (>100 MeV for protons) at ``table-top'' scales. We have discovered and utilized a self-organizing scheme that exploits persisting self-generated plasma electric ( 0.1 TV/m) and magnetic ( 104 Tesla) fields to reduce the ion-energy (Ei) spread after the laser exits the plasma, thus separating acceleration from spread reduction. In this way we routinely generate aluminum and carbon beams with narrow spectral peaks at Ei up to 310 MeV and 220 MeV, respectively, with high efficiency ( 5%). The experimental demonstration has been done at the LANL Trident laser with 0.12 PW, high-contrast, 0.65 ps Gaussian laser pulses irradiating planar foils up to 250 nm thick. In this regime, Ei scales empirically with laser intensity (I) as I 1 / 2. Our progress is enabled by high-fidelity, massive computer simulations of the experiments. This work advances next-generation compact accelerators suitable for new applications. E . g ., a carbon beam with Ei 400 MeV and 10% energy spread is suitable for fast ignition (FI) of compressed DT. The observed scaling suggests that is feasible with existing target fabrication and PW-laser technologies, using a sub-ps laser pulse with I 2.5 ×1021 W/cm2. These beams have been used on Trident to generate warm-dense matter at solid-densities, enabling us to investigate its equation of state and mixing of heterogeneous interfaces purely by plasma effects distinct from hydrodynamics. They also drive an intense neutron-beam source with great promise for important applications such as active interrogation of shielded nuclear materials. Considerations on controlling ion-beam divergence for their increased utility are discussed. Funded by the LANL LDRD program.

  2. Analytical solutions for radiation-driven winds in massive stars. I. The fast regime

    Energy Technology Data Exchange (ETDEWEB)

    Araya, I.; Curé, M. [Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso Av. Gran Bretaña 1111, Casilla 5030, Valparaíso (Chile); Cidale, L. S., E-mail: ignacio.araya@uv.cl [Departamento de Espectroscopía, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata (UNLP), and Instituto de Astrofísica La Plata, CCT La Plata, CONICET-UNLP Paseo del Bosque S/N, 1900 La Plata (Argentina)

    2014-11-01

    Accurate mass-loss rate estimates are crucial keys in the study of wind properties of massive stars and for testing different evolutionary scenarios. From a theoretical point of view, this implies solving a complex set of differential equations in which the radiation field and the hydrodynamics are strongly coupled. The use of an analytical expression to represent the radiation force and the solution of the equation of motion has many advantages over numerical integrations. Therefore, in this work, we present an analytical expression as a solution of the equation of motion for radiation-driven winds in terms of the force multiplier parameters. This analytical expression is obtained by employing the line acceleration expression given by Villata and the methodology proposed by Müller and Vink. On the other hand, we find useful relationships to determine the parameters for the line acceleration given by Müller and Vink in terms of the force multiplier parameters.

  3. Ion temperature anisotropy effects on threshold conditions of a shear-modified current driven electrostatic ion-acoustic instability in the topside auroral ionosphere

    Directory of Open Access Journals (Sweden)

    P. J. G. Perron

    2013-03-01

    Full Text Available Temperature anisotropies may be encountered in space plasmas when there is a preferred direction, for instance, a strong magnetic or electric field. In this paper, we study how ion temperature anisotropy can affect the threshold conditions of a shear-modified current driven electrostatic ion-acoustic (CDEIA instability. In particular, this communication focuses on instabilities in the context of topside auroral F-region situations and in the limit where finite Larmor radius corrections are small. We derived a new fluid-like expression for the critical drift which depends explicitly on ion anisotropy. More importantly, for ion to electron temperature ratios typical of F-region, solutions of the kinetic dispersion relation show that ion temperature anisotropy may significantly lower the drift threshold required for instability. In some cases, a perpendicular to parallel ion temperature ratio of 2 and may reduce the relative drift required for the onset of instability by a factor of approximately 30, assuming the ion-acoustic speed of the medium remains constant. Therefore, the ion temperature anisotropy should be considered in future studies of ion-acoustic waves and instabilities in the high-latitude ionospheric F-region.

  4. Line-driven disk wind model for ultra-fast outflows in active galactic nuclei -- Scaling with luminosity

    CERN Document Server

    Nomura, Mariko

    2016-01-01

    In order to reveal the origin of the ultra-fast outflows (UFOs) that are frequently observed in active galactic nuclei (AGNs), we perform two-dimensional radiation hydrodynamics simulations of the line-driven disk winds, which are accelerated by the radiation force due to the spectral lines. The line-driven winds are successfully launched for the range of $M_{\\rm BH}=10^{6-9}M_\\odot$ and $\\varepsilon$=0.1-0.5, and the resulting mass outflow rate ($\\dot{M_{\\rm w}}$), momentum flux ($\\dot{p_{\\rm w}}$), and kinetic luminosity ($\\dot{E_{\\rm w}}$) are in the region containing 90% of the posterior probability distribution in the $\\dot M_{\\rm w}$-$L_{\\rm bol}$ plane, $\\dot p_{\\rm w}$-$L_{\\rm bol}$ plane, and $\\dot E_{\\rm w}$-$L_{\\rm bol}$ plane shown in Gofford et al., where $M_{\\rm BH}$ is the black hole mass, $\\varepsilon$ is the Eddington ratio, and $L_{\\rm bol}$ is the bolometric luminosity. The best-fitting relations in Gofford et al., $d\\log\\dot{M_{\\rm w}}/d\\log{L_{\\rm bol}}\\sim 0.9$, $d\\log\\dot{p_{\\rm w}}/d\\l...

  5. Measurements accounting for the impediment of ion spin-up in rotating magnetic field driven field reversed configurations

    Energy Technology Data Exchange (ETDEWEB)

    Deards, C. L. [Lockheed Martin, 1011 Lockheed Way, Palmdale, California 93599 (United States); Hoffman, A. L.; Steinhauer, L. C. [Redmond Plasma Physics Laboratory, University of Washington, 14700 NE 95th Street, Suite 100, Redmond, Washington 98052 (United States)

    2011-11-15

    Improved vacuum hygiene, wall conditioning, and reduced recycling in the rotating magnetic field (RMF) driven translation, confinement, and sustainment-upgrade (TCSU) field reversed configuration experiment have made possible a more accurate assessment of the forces affecting ion spin-up. This issue is critical in plasmas sustained by RMFs, such as TCSU since ion spin-up can substantially reduce or cancel the RMF current drive effect. Several diagnostics are brought to bear, including a 3-axis translatable magnetic probe allowing the first experimental measurement of the end shorting effect. These results show that the ion rotation is determined by a balance between electron-ion friction, the end shorting effect, and ion drag against neutrals.

  6. Measurements accounting for the impediment of ion spin-up in rotating magnetic field driven field reversed configurations

    Science.gov (United States)

    Deards, C. L.; Hoffman, A. L.; Steinhauer, L. C.

    2011-11-01

    Improved vacuum hygiene, wall conditioning, and reduced recycling in the rotating magnetic field (RMF) driven translation, confinement, and sustainment-upgrade (TCSU) field reversed configuration experiment have made possible a more accurate assessment of the forces affecting ion spin-up. This issue is critical in plasmas sustained by RMFs, such as TCSU since ion spin-up can substantially reduce or cancel the RMF current drive effect. Several diagnostics are brought to bear, including a 3-axis translatable magnetic probe allowing the first experimental measurement of the end shorting effect. These results show that the ion rotation is determined by a balance between electron-ion friction, the end shorting effect, and ion drag against neutrals.

  7. Ultra-fast nano-scale phase transitions in systems driven far from equilibrium

    Science.gov (United States)

    Caro, A.; Lopasso, E. M.; Caro, M.; Turchi, P. E. A.

    2004-03-01

    We study the thermodynamic forces acting on the evolution of the nanoscale regions excited by laser shots into solid targets. We analyze the role of diffusion, thermo-migration, and the liquidus-solidus two-phase field crossing, as the system cools down from the induced melt under different conditions of energy deposition. To determine the relevance of these thermodynamic forces, solute redistribution is evaluated using molecular dynamics simulations of equilibrium Au-Ni solid solutions. Our results show the combined effects of thermo-migration and solute redistribution that, depending on the material, can reinforce or cancel each other. These effects show that the combination of ultra-fast but nano-scale characteristics of these processes can be used to produce nanoscale modifications of composition in alloys

  8. Experimental Evaluation of Energy Transfer between Fast Ions and Alfven Eigenmodes

    Science.gov (United States)

    Nagaoka, Kenichi; Osakabe, Masaki; Isobe, Mitsutaka; Ogawa, Kunihiro; Suzuki, Yasuhiro; Kobayashi, Shinji; Yamamoto, Satoshi; Miyoshi, Yoshizumi; Katoh, Yuto; Fontdecaba, Josep Maria; Ascasibar, Enrique; LHD Team

    2016-10-01

    Recently, a new wave-particle analyzer was proposed to identify interaction between fast ions and Alfven eigenmodes [K. Nagaoka, 67th annual meeting of APS-DPP, savanna, 2015]. A data acquisition system for the wave-particle interaction analysis was developed for particle counting mode operation of neutral particle detectors. We recently applied the system to the Si-FNA detector signals in LHD and Heliotron J, and NPA signals in TJ-II. The first experimental results obtained in three devices are presented and the importance of the optimization of line of sight will be discussed. This research was supported by NIFS/NINS under the project of 'Promotion of International Network for Scientific Collaboration', NIFS Collaboration Research program (NIFS16KUHL068) and JSPS KAKENHI Grani-in-Aid for Young Scientists (A) 26709071.

  9. Spatial distribution of {gamma} emissivity and fast ions during ({sup 3}He)D ICRF heating experiments on JET

    Energy Technology Data Exchange (ETDEWEB)

    Start, D.F.H. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Righi, E. [Imperial Coll. of Science and Technology, London (United Kingdom); Warrick, C. [UKAEA Culham Lab., Abingdon (United Kingdom)

    1994-07-01

    A model is presented that can simulate the {gamma} emissivity in the poloidal cross-section during ({sup 3}He)D ICRF heated discharges in JET plasmas, by merging information obtained from the fast ion distribution and from nuclear reactions producing the observed {gamma} emissivity (production of {gamma} photons during {sup 3}He-{sup 9}Be reactions). This technique can play an important role in the identification of plasma instabilities that affect the redistribution of the fast ions in the plasma, like the TAE modes and the ripple in the tokamak magnetic field. 9 refs., 4 figs., 1 tab.

  10. Design and testing of a dc ion injector suitable for accelerator-driven transmutation

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, J.D.; Meyer, E.; Stevens, R.R. Jr.; Hansborough, L.; Sherman, J.

    1994-08-01

    For a number of years, Los Alamos have collaborated with a team of experimentalists at Chalk River Labs who were pursuing the development of the front end of a high power cw proton accelerator. With the help of internal laboratory funding and modest defense conversion funds, we have set up and operated the accelerator at Los Alamos Operational equipment includes a slightly modified Chalk River Injector Test Stand (CRITS) including a 50 keV proton injector and a 1.25 MeV radio-frequency quadrupole (RFQ) with a klystrode rf power system. Many of the challenges involved in operating an rf linear accelerator to provide neutrons for an accelerator-driven reactor are encountered at the front (low energy) end of this system. The formation of the ion beam, the control of the beam parameters, and the focusing and matching of a highly space-charge-dominated beam are major problems. To address the operating problems in this critical front end, the Accelerator Operations and Technology Division at the Los Alamos National Laboratory has designed the APDF (Accelerator Prototype Demonstration Facility). The front end of this facility is a 75 keV, high-current, ion injector which has been assembled and is now being tested. This paper discusses the design modifications required in going from the 50 keV CRITS injector to the higher current, 75 keV injector. Major innovative changes were made in the design of this injector. This design eliminates all the control electronics and most of the ion source equipment at high potential. Also, a new, high-quality, ion-extractor system has been built. A dual-solenoid lens will be used in the low energy beam transport (LEBT) line to provide the capability of matching the extracted beam to a high-current ADTT linac. This new injector is the first piece of hardware in the APDF program and will be used to develop the long-term, reliable cw beam operation required for ADIT applications.

  11. Interaction of powerful hot plasma and fast ion streams with materials in dense plasma focus devices

    Energy Technology Data Exchange (ETDEWEB)

    Chernyshova, M., E-mail: maryna.chernyshova@ipplm.pl [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Gribkov, V.A. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Institution of Russian Academy of Sciences A.A. Baikov Institute of Metallurgy and Material Science RAS, Moscow (Russian Federation); Kowalska-Strzeciwilk, E.; Kubkowska, M.; Miklaszewski, R.; Paduch, M.; Pisarczyk, T.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Demina, E.V.; Pimenov, V.N.; Maslyaev, S.A. [Institution of Russian Academy of Sciences A.A. Baikov Institute of Metallurgy and Material Science RAS, Moscow (Russian Federation); Bondarenko, G.G. [National Research University Higher School of Economics (HSE), Moscow (Russian Federation); Vilemova, M.; Matejicek, J. [Institute of Plasma Physics of the CAS, Prague (Czech Republic)

    2016-12-15

    Highlights: • Materials perspective for use in mainstream nuclear fusion facilities were studied. • Powerful streams of hot plasma and fast ions were used to induce irradiation. • High temporal, spatial, angular and spectral resolution available in experiments. • Results of irradiation were investigated by number of analysis techniques. - Abstract: A process of irradiating and ablating solid-state targets with hot plasma and fast ion streams in two Dense Plasma Focus (DPF) devices – PF-6 and PF-1000 was examined by applying a number of diagnostics of nanosecond time resolution. Materials perspective for use in chambers of the mainstream nuclear fusion facilities (mainly with inertial plasma confinement like NIF and Z-machine), intended both for the first wall and for constructions, have been irradiated in these simulators. Optical microscopy, SEM, Atomic Emission Spectroscopy, images in secondary electrons and in characteristic X-ray luminescence of different elements, and X-ray elemental analysis, gave results on damageability for a number of materials including low-activated ferritic and austenitic stainless steels, β-alloy of Ti, as well as two types of W and a composite on its base. With an increase of the number of shots irradiating the surface, its morphology changes from weakly pronounced wave-like structures or ridges to strongly developed ones. At later stages, due to the action of the secondary plasma produced near the target materials they melted, yielding both blisters and a fracturing pattern: first along the grain and then “in-between” the grains creating an intergranular net of microcracks. At the highest values of power flux densities multiple bubbles appeared. Furthermore, in this last case the cracks were developed because of microstresses at the solidification of melt. Presence of deuterium within the irradiated ferritic steel surface nanolayers is explained by capture of deuterons in lattice defects of the types of impurity atoms

  12. Thermal Analysis of a Fast Charging Technique for a High Power Lithium-Ion Cell

    Directory of Open Access Journals (Sweden)

    Victor Manuel García Fernández

    2016-11-01

    Full Text Available The cell case temperature versus time profiles of a multistage fast charging technique (4C-1C-constant voltage (CV/fast discharge (4C in a 2.3 Ah cylindrical lithium-ion cell are analyzed using a thermal model. Heat generation is dominated by the irreversible component associated with cell overpotential, although evidence of the reversible component is also observed, associated with the heat related to entropy from the electrode reactions. The final charging stages (i.e., 1C-CV significantly reduce heat generation and cell temperature during charge, resulting in a thermally safe charging protocol. Cell heat capacity was determined from cell-specific heats and the cell materials’ thickness. The model adjustment of the experimental data during the 2 min resting period between discharge and charge allowed us to calculate both the time constant of the relaxation process and the cell thermal resistance. The obtained values of these thermal parameters used in the proposed model are almost equal to those found in the literature for the same cell model, which suggests that the proposed model is suitable for its implementation in thermal management systems.

  13. Proton-driven amide bond-cleavage pathways of gas-phase peptide ions lacking mobile protons.

    Science.gov (United States)

    Bythell, Benjamin J; Suhai, Sándor; Somogyi, Arpád; Paizs, Béla

    2009-10-07

    The mobile proton model (Dongre, A. R., Jones, J. L., Somogyi, A. and Wysocki, V. H. J. Am. Chem. Soc. 1996, 118 , 8365-8374) of peptide fragmentation states that the ionizing protons play a critical role in the gas-phase fragmentation of protonated peptides upon collision-induced dissociation (CID). The model distinguishes two classes of peptide ions, those with or without easily mobilizable protons. For the former class mild excitation leads to proton transfer reactions which populate amide nitrogen protonation sites. This enables facile amide bond cleavage and thus the formation of b and y sequence ions. In contrast, the latter class of peptide ions contains strongly basic functionalities which sequester the ionizing protons, thereby often hindering formation of sequence ions. Here we describe the proton-driven amide bond cleavages necessary to produce b and y ions from peptide ions lacking easily mobilizable protons. We show that this important class of peptide ions fragments by different means from those with easily mobilizable protons. We present three new amide bond cleavage mechanisms which involve salt-bridge, anhydride, and imine enol intermediates, respectively. All three new mechanisms are less energetically demanding than the classical oxazolone b(n)-y(m) pathway. These mechanisms offer an explanation for the formation of b and y ions from peptide ions with sequestered ionizing protons which are routinely fragmented in large-scale proteomics experiments.

  14. Radioactive Ion Beam Production by Fast-Neutron-Induced Fission in Actinide Targets at EURISOL

    CERN Document Server

    Herrera-Martínez, Adonai

    The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, the production of high-intensity RIBs of specific neutron-rich isotopes is obtained by inducing fission in large-mass actinide targets. In our contribution, the use of uranium targets is shown to be advantageous to other materials, such as thorium. Therefore, in order to produce fissions in U-238 and reduce the plutonium inventory, a fast neutron energy spectrum is necessary. The large beam power required to achieve these RIB levels requires the use of a liquid proton-to-neutron converter. This article details the design parameters of the converter, with special attention to the coupled neutronics of the liquid converter and fission target. Calculations performed with the ...

  15. Isomeric signatures in the fragmentation of pyridazine and pyrimidine induced by fast ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Montenegro, Eduardo C. [Instituto de Física, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro, RJ (Brazil)

    2015-07-28

    We present fast proton impact induced fragmentations of pyrimidine and pyridazine as an experimental resource to investigate isomeric signatures. Major isomeric imprints are identified for few fragment ions and differences of more than an order of magnitude for the cross sections of fragments of the same mass were measured. The observation of the molecular structure of these isomers gives no apparent indication for the reasons for such substantial differences. It is verified that the simple displacement of the position of one nitrogen atom strongly inhibits or favors the production of some ionic fragment species. The dependency of the fragmentation cross sections on the proton impact energy, investigated by means of time of flight mass spectroscopy and of a model calculation based in first order perturbation theory, allows us to disentangle the complex collision dynamics of the ionic fragments. The proton-induced fragmentation discriminates rather directly the association between a molecular orbital ionization and the fragment-ions creation and abundance, as well as how the redistribution of the energy imparted to the molecules takes place, triggering not only single but also double vacancy and leads to specific fragmentation pathways.

  16. Fast Hydrogen-Air Flames for Turbulence Driven Deflagration to Detonation Transition

    Science.gov (United States)

    Chambers, Jessica; Ahmed, Kareem

    2016-11-01

    Flame acceleration to Detonation produces several combustion modes as the Deflagration-to-Detonation Transition (DDT) is initiated, including fast deflagration, auto-ignition, and quasi-detonation. Shock flame interactions and turbulence levels in the reactant mixture drive rapid flame expansion, formation of a leading shockwave and post-shock conditions. An experimental study to characterize the developing shock and flame front behavior of propagating premixed hydrogen-air flames in a square channel is presented. To produce each flame regime, turbulence levels and flame propagation velocity are controlled using perforated plates in several configurations within the experimental facility. High speed optical diagnostics including Schlieren and Particle Image Velocimetry are used to capture the flow field. In-flow pressure measurements acquired post-shock, detail the dynamic changes that occur in the compressed gas directly ahead of the propagating flame. Emphasis on characterizing the turbulent post-shock environment of the various flame regimes helps identify the optimum conditions to initiate the DDT process. The study aims to further the understanding of complex physical mechanisms that drive transient flame conditions for detonation initiation. American Chemical Society.

  17. First measurements of D(α) spectrum produced by anisotropic fast ions in the gas dynamic trap.

    Science.gov (United States)

    Lizunov, A; Anikeev, A

    2014-11-01

    Angled injection of eight deuterium beams in gas dynamic trap (GDT) plasmas builds up the population of fast ions with the distribution function, which conserves a high degree of initial anisotropy in space, energy, and pitch angle. Unlike the Maxwellian distribution case, the fast ion plasma component in GDT cannot be exhaustively characterized by the temperature and density. The instrumentation complex to study of fast ions is comprised of motional Stark effect diagnostic, analyzers of charge exchange atoms, and others. The set of numerical codes using for equilibrium modeling is also an important tool of analysis. In the recent campaign of summer 2014, we recorded first signals from the new fast ion D-alpha diagnostic on GDT. This paper presents the diagnostic description and results of pilot measurements. The diagnostic has four lines of sight, distributed across the radius of an axially symmetric plasma column in GDT. In the present setup, a line-integrated optical signal is measured in each channel. In the transverse direction, the spatial resolution is 18 mm. Collected light comes to the grating spectrometer with the low-noise detector based on a charge-coupled device matrix. In the regime of four spectra stacked vertically on the sensor, the effective spectral resolution of measurements is approximately 0.015 nm. Exposure timing is provided by the fast optical ferroelectric crystal shutter, allowing frames of duration down to 70 μs. This number represents the time resolution of measurements. A large dynamic range of the camera permits for a measurement of relatively small light signals produced by fast ions on top of the bright background emission from the bulk plasma. The fast ion emission has a non-Gaussian spectrum featuring the characteristic width of approximately 4 nm, which can be separated from relatively narrow Gaussian lines of D-alpha and H-alpha coming from the plasma periphery, and diagnostic beam emission. The signal to noise ratio varies

  18. First measurements of D{sub α} spectrum produced by anisotropic fast ions in the gas dynamic trap

    Energy Technology Data Exchange (ETDEWEB)

    Lizunov, A.; Anikeev, A. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2014-11-15

    Angled injection of eight deuterium beams in gas dynamic trap (GDT) plasmas builds up the population of fast ions with the distribution function, which conserves a high degree of initial anisotropy in space, energy, and pitch angle. Unlike the Maxwellian distribution case, the fast ion plasma component in GDT cannot be exhaustively characterized by the temperature and density. The instrumentation complex to study of fast ions is comprised of motional Stark effect diagnostic, analyzers of charge exchange atoms, and others. The set of numerical codes using for equilibrium modeling is also an important tool of analysis. In the recent campaign of summer 2014, we recorded first signals from the new fast ion D-alpha diagnostic on GDT. This paper presents the diagnostic description and results of pilot measurements. The diagnostic has four lines of sight, distributed across the radius of an axially symmetric plasma column in GDT. In the present setup, a line-integrated optical signal is measured in each channel. In the transverse direction, the spatial resolution is 18 mm. Collected light comes to the grating spectrometer with the low-noise detector based on a charge-coupled device matrix. In the regime of four spectra stacked vertically on the sensor, the effective spectral resolution of measurements is approximately 0.015 nm. Exposure timing is provided by the fast optical ferroelectric crystal shutter, allowing frames of duration down to 70 μs. This number represents the time resolution of measurements. A large dynamic range of the camera permits for a measurement of relatively small light signals produced by fast ions on top of the bright background emission from the bulk plasma. The fast ion emission has a non-Gaussian spectrum featuring the characteristic width of approximately 4 nm, which can be separated from relatively narrow Gaussian lines of D-alpha and H-alpha coming from the plasma periphery, and diagnostic beam emission. The signal to noise ratio varies

  19. Cyclotron resonances of ions with obliquely propagating waves in coronal holes and the fast solar wind

    Science.gov (United States)

    Hollweg, Joseph V.; Markovskii, S. A.

    2002-06-01

    There is a growing consensus that cyclotron resonances play important roles in heating protons and ions in coronal holes where the fast solar wind originates and throughout interplanetary space as well. Most work on cyclotron resonant interactions has concentrated on the special, but unrealistic, case of propagation along the ambient magnetic field, B0, because of the great simplification it gives. This paper offers a physical discussion of how the cyclotron resonances behave when the waves propagate obliquely to B0. We show how resonances at harmonics of the cyclotron frequency come about, and how the physics can be different depending on whether E⊥ is in or perpendicular to the plane containing k and B0 (k is wave vector, and E⊥ is the component of the wave electric field perpendicular to B0). If E⊥ is in the k-B0 plane, the resonances are analogous to the Landau resonance and arise because the particle tends to stay in phase with the wave during the part of its orbit when it is interacting most strongly with E⊥. If E⊥ is perpendicular to the k-B0 plane, then the resonances depend on the fact that the particle is at different positions during the parts of its orbit when it is interacting most strongly with E⊥. Our main results are our refid="df10" type="formula">equations (10), refid="df11" type="formula">(11), and refid="df13" type="formula">(13) for the secular rate of energy gain (or loss) by a resonant particle and the unfamiliar result that ions can resonate with a purely right-hand circularly polarized wave if the propagation is oblique. We conclude with some speculations about the origin of highly obliquely propagating ion resonant waves in the corona and solar wind. We point out that there are a number of instabilities that may generate such waves locally in the corona and solar wind.

  20. Reduction of angular divergence of laser-driven ion beams during their acceleration and transport

    Science.gov (United States)

    Zakova, M.; Pšikal, Jan; Margarone, Daniele; Maggiore, Mario; Korn, G.

    2015-05-01

    Laser plasma physics is a field of big interest because of its implications in basic science, fast ignition, medicine (i.e. hadrontherapy), astrophysics, material science, particle acceleration etc. 100-MeV class protons accelerated from the interaction of a short laser pulse with a thin target have been demonstrated. With continuing development of laser technology, greater and greater energies are expected, therefore projects focusing on various applications are being formed, e.g. ELIMAIA (ELI Multidisciplinary Applications of laser-Ion Acceleration). One of the main characteristic and crucial disadvantage of ion beams accelerated by ultra-short intense laser pulses is their large divergence, not suitable for the most of applications. In this paper two ways how to decrease beam divergence are proposed. Firstly, impact of different design of targets on beam divergence is studied by using 2D Particlein-cell simulations (PIC). Namely, various types of targets include at foils, curved foil and foils with diverse microstructures. Obtained results show that well-designed microstructures, i.e. a hole in the center of the target, can produce proton beam with the lowest divergence. Moreover, the particle beam accelerated from a curved foil has lower divergence compared to the beam from a flat foil. Secondly, another proposed method for the divergence reduction is using of a magnetic solenoid. The trajectories of the laser accelerated particles passing through the solenoid are modeled in a simple Matlab program. Results from PIC simulations are used as input in the program. The divergence is controlled by optimizing the magnetic field inside the solenoid and installing an aperture in front of the device.

  1. Harmonic analysis of irradiation asymmetry for cylindrical implosions driven by high-frequency rotating ion beams

    CERN Document Server

    Bret, Antoine; Tahir, Naeem

    2012-01-01

    Cylindrical implosions driven by intense heavy ions beams should be instrumental in a near future to study High Energy Density Matter. By rotating the beam by means of a high frequency wobbler, it should be possible to deposit energy in the outer layers of a cylinder, compressing the material deposited in its core. The beam temporal profile should however generate an inevitable irradiation asymmetry likely to feed the Rayleigh-Taylor instability (RTI) during the implosion phase. In this paper, we compute the Fourier components of the target irradiation in order to make the junction with previous works on RTI performed in this setting. Implementing a 1D and 2D beam models, we find these components can be expressed exactly in terms of the Fourier transform of the temporal beam profile. If $T$ is the beam duration and $\\Omega$ its rotation frequency, "magic products" $\\Omega T$ can be identified which cancel the first harmonic of the deposited density, resulting in an improved irradiation symmetry.

  2. Carbon nanoparticle stabilised liquid|liquid micro-interfaces for electrochemically driven ion-transfer processes

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, Stuart M. [Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom); Fletcher, Paul D.I.; Cui Zhenggang [Department of Physical Sciences, Chemistry and Physics, University of Hull, Hull HU6 7RX (United Kingdom); Opallo, Marcin [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland); Chen Jingyuan [Department of Applied Physics, University of Fukui, 3-9-1, Bunkyo, Fukui-shi 910-8507 (Japan); Marken, Frank [Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom)], E-mail: F.Marken@bath.ac.uk

    2007-12-20

    Stabilised liquid|liquid interfaces between an organic 4-(3-phenylpropyl)-pyridine (PPP) phase and an aqueous electrolyte phase are obtained in the presence of suitable nanoparticles. The use of nanoparticulate stabilisers (ca. 30 nm diameter laponite or 9-18 nm diameter carbon) in 'Pickering' emulsion systems allows stable organic microdroplets to be formed and these are readily deposited onto conventional tin-doped indium oxide (ITO) electrodes. In contrast to the electrically insulating laponite nanoparticles, conducting carbon nanoparticles are shown to effectively catalyse the simultaneous electron transfer and ion transfer process at triple phase boundary junctions. Anion transfer processes between the aqueous and organic phase are driven electrochemically at the extensive triple phase junction carbon nanoparticle|4-(3-phenylpropyl)-pyridine|aqueous electrolyte. The organic phase consists of a redox active reagent 5,10,15,20-tetraphenyl-21H,23H-porphinato manganese(III) (MnTPP{sup +}), 5,10,15,20-tetraphenyl-21H,23H-porphinato iron(III) (FeTPP{sup +}), or proto-porphyrinato-IX iron(III) (hemin) dissolved in 4-(3-phenylpropyl)-pyridine (PPP). The composition of the aqueous electrolyte phase determines the reversible potential for the Nernstian anion transfer process. The methodology is shown to be versatile and, in future, could be applied more generally in liquid|liquid electroanalysis.

  3. The effect of diamagnetic flows on turbulent driven ion toroidal rotation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. P. [Courant Institute of Mathematical Sciences, New York University, New York, New York 10003 (United States); Barnes, M. [Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States); Parra, F. I. [Rudolf Peierls Centre for Theoretical Physics, Oxford University, Oxford OX1 3NP (United Kingdom); Belli, E. A.; Candy, J. [General Atomics, San Diego, California 92121 (United States)

    2014-05-15

    Turbulent momentum redistribution determines the radial profile of rotation in a tokamak. The momentum transport driven by diamagnetic flow effects is an important piece of the radial momentum transport for sub-sonic rotation, which is often observed in experiments. In a non-rotating state, the diamagnetic flow and the E × B flow must cancel. The diamagnetic flow and the E × B flow have different effects on the turbulent momentum flux, and this difference in behavior induces intrinsic rotation. The momentum flux is evaluated using gyrokinetic equations that are corrected to higher order in the ratio of the poloidal Larmor radius to the minor radius, which requires evaluation of the diamagnetic corrections to Maxwellian equilibria. To study the momentum transport due to diamagnetic flow effects, three experimental observations of ion rotation are examined. First, a strong pressure gradient at the plasma edge is shown to result in a significant inward momentum transport due to the diamagnetic effect, which may explain the observed peaking of rotation in a high confinement mode. Second, the direction of momentum transport is shown to change as collisionality increases, which is qualitatively consistent with the observed reversal of intrinsic rotation by varying plasma density and current. Last, the dependence of the intrinsic momentum flux on the magnetic shear is found, and it may explain the observed rotation changes in the presence of lower hybrid current drive.

  4. Benchmark and combined velocity-space tomography of fast-ion D-alpha spectroscopy and collective Thomson scattering measurements

    DEFF Research Database (Denmark)

    Jacobsen, Asger Schou; Salewski, Mirko; Geiger, B.

    2016-01-01

    We demonstrate the combination of fast-ion D-alpha spectroscopy (FIDA) and collective Thomson scattering (CTS) measurements to determine a common best estimate of the fastion velocity distribution function by velocity-space tomography. We further demonstrate a benchmark of FIDA tomography and CTS...

  5. Feasibility of inferring the full fast-ion distribution function via Orbit Tomography at the DIII-D Tokamak

    Science.gov (United States)

    Stagner, L.; Heidbrink, W. W.

    2016-10-01

    The sensitivity of fast-ion diagnostics to different regions of the fast-ion distribution (FID) phase space can be calculated. These phase space sensitivities when convolved with a local FID gives the expected experimental measurement. This process can be reversed to reconstruct the local FID from many experimental measurements in a method known as Velocity-space Tomography (VST). However, VST requires many radially overlapping measurement volumes which limits its applicability since most existing diagnostics are setup as radially separated arrays. Orbit Tomography (OT), an extension of VST that allows for the inference of the full FID, has been proposed as a solution to this problem. Unlike VST which reconstructs the fast-ion density on a 2D energy-pitch grid, OT infers the number of fast-ions on a particular orbit. This naturally correlates different radial locations allowing for any viewing chord to be used in the analysis. In the present work we will give an overview of OT and demonstrate its feasibility with the current diagnostic capability of the DIII-D tokamak. Work supported by the US DOE under Award DE-FC02-04ER54698.

  6. High-performance rechargeable batteries with nanoparticle active materials, photochemically regenerable active materials, and fast solid-state ion conductors

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, Joseph C.

    2017-04-04

    A high-performance rechargeable battery using ultra-fast ion conductors. In one embodiment the rechargeable battery apparatus includes an enclosure, a first electrode operatively connected to the enclosure, a second electrode operatively connected to the enclosure, a nanomaterial in the enclosure, and a heat transfer unit.

  7. Spectrum response and analysis of 77 GHz band collective Thomson scattering diagnostic for bulk and fast ions in LHD plasmas

    DEFF Research Database (Denmark)

    Nishiura, M.; Kubo, S.; Tanaka, K.

    2014-01-01

    A collective Thomson scattering (CTS) diagnostic was developed and used to measure the bulk and fast ions originating from 180 keV neutral beams in the Large Helical Device (LHD). Electromagnetic waves from a gyrotron at 77 GHz with 1 MW power output function as both the probe and electron cyclot...

  8. Detection of nitro-based and peroxide-based explosives by fast polarity-switchable ion mobility spectrometer with ion focusing in vicinity of Faraday detector.

    Science.gov (United States)

    Zhou, Qinghua; Peng, Liying; Jiang, Dandan; Wang, Xin; Wang, Haiyan; Li, Haiyang

    2015-05-29

    Ion mobility spectrometer (IMS) has been widely deployed for on-site detection of explosives. The common nitro-based explosives are usually detected by negative IMS while the emerging peroxide-based explosives are better detected by positive IMS. In this study, a fast polarity-switchable IMS was constructed to detect these two explosive species in a single measurement. As the large traditional Faraday detector would cause a trailing reactant ion peak (RIP), a Faraday detector with ion focusing in vicinity was developed by reducing the detector radius to 3.3 mm and increasing the voltage difference between aperture grid and its front guard ring to 591 V, which could remove trailing peaks from RIP without loss of signal intensity. This fast polarity-switchable IMS with ion focusing in vicinity of Faraday detector was employed to detect a mixture of 10 ng 2,4,6-trinitrotoluene (TNT) and 50 ng hexamethylene triperoxide diamine (HMTD) by polarity-switching, and the result suggested that [TNT-H](-) and [HMTD+H](+) could be detected in a single measurement. Furthermore, the removal of trailing peaks from RIP by the Faraday detector with ion focusing in vicinity also promised the accurate identification of KClO4, KNO3 and S in common inorganic explosives, whose product ion peaks were fairly adjacent to RIP.

  9. One-volt-driven superfast polymer actuators based on single-ion conductors

    Science.gov (United States)

    Kim, Onnuri; Kim, Hoon; Choi, U. Hyeok; Park, Moon Jeong

    2016-11-01

    The key challenges in the advancement of actuator technologies related to artificial muscles include fast-response time, low operation voltages and durability. Although several researchers have tackled these challenges over the last few decades, no breakthrough has been made. Here we describe a platform for the development of soft actuators that moves a few millimetres under 1 V in air, with a superfast response time of tens of milliseconds. An essential component of this actuator is the single-ion-conducting polymers that contain well-defined ionic domains through the introduction of zwitterions; this achieved an exceptionally high dielectric constant of 76 and a 300-fold enhancement in ionic conductivity. Moreover, the actuator demonstrated long-term durability, with negligible changes in the actuator stroke over 20,000 cycles in air. Owing to its low-power consumption (only 4 mW), we believe that this actuator could pave the way for cutting-edge biomimetic technologies in the future.

  10. Defects in metal crystals. Progress report, May 1, 1976--April 30, 1977. [Heavy ions and fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Seidman, D N

    1977-02-01

    Work performed during 1976 to investigate point defects, aggregates of point defects and their interactions with one another is described. Strong emphasis is placed on the use of different irradiating species (300 to 700 eV Xe/sup +/ ions, 300 eV and 30 keV He/sup +/ ions, 20- to 40-keV W/sup +/ ions, 20- to 40-keV Mo/sup +/ ions, 20- to 40-keV Cr/sup +/ ions and fast neutrons) to introduce both vacancies and interstitials in a number of pure metals (Mo, W, Au, Ta) and alloys (Pt-Au, W-Re, Mo-Ti, Mo-Ti-Zr, Ni/sub 4/Mo, Ni/sub 3/Fe, Ni/sub 3/Mn, low swelling 316 stainless steel and commercial 316 stainless steel). (GHT)

  11. A 5D gyrokinetic full- f global semi-Lagrangian code for flux-driven ion turbulence simulations

    Science.gov (United States)

    Grandgirard, V.; Abiteboul, J.; Bigot, J.; Cartier-Michaud, T.; Crouseilles, N.; Dif-Pradalier, G.; Ehrlacher, Ch.; Esteve, D.; Garbet, X.; Ghendrih, Ph.; Latu, G.; Mehrenberger, M.; Norscini, C.; Passeron, Ch.; Rozar, F.; Sarazin, Y.; Sonnendrücker, E.; Strugarek, A.; Zarzoso, D.

    2016-10-01

    This paper addresses non-linear gyrokinetic simulations of ion temperature gradient (ITG) turbulence in tokamak plasmas. The electrostatic GYSELA code is one of the few international 5D gyrokinetic codes able to perform global, full- f and flux-driven simulations. Its has also the numerical originality of being based on a semi-Lagrangian (SL) method. This reference paper for the GYSELA code presents a complete description of its multi-ion species version including: (i) numerical scheme, (ii) high level of parallelism up to 500k cores and (iii) conservation law properties.

  12. Kinetic effects on the transition to relativistic self-induced transparency in laser-driven ion acceleration

    CERN Document Server

    Siminos, E; Grech, M; Fülöp, T

    2016-01-01

    We study kinetic effects responsible for the transition to relativistic self-induced transparency in the interaction of a circularly-polarized laser-pulse with an overdense plasma and their relation to hole-boring and ion acceleration. It is shown, using particle-in-cell simulations and an analysis of separatrices in single-particle phase-space, that this transition is mediated by the complex interplay of fast electron dynamics and ion motion at the initial stage of the interaction. It thus depends on the ion charge-to-mass ratio and can be controlled by varying the laser temporal profile. Moreover, we find a new regime in which a transition from relativistic transparency to hole-boring occurs dynamically during the course of the interaction. It is shown that, for a fixed laser intensity, this dynamic transition regime allows optimal ion acceleration in terms of both energy and energy spread.

  13. Ion channel density regulates switches between regular and fast spiking in soma but not in axons.

    Directory of Open Access Journals (Sweden)

    Hugo Zeberg

    2010-04-01

    Full Text Available The threshold firing frequency of a neuron is a characterizing feature of its dynamical behaviour, in turn determining its role in the oscillatory activity of the brain. Two main types of dynamics have been identified in brain neurons. Type 1 dynamics (regular spiking shows a continuous relationship between frequency and stimulation current (f-I(stim and, thus, an arbitrarily low frequency at threshold current; Type 2 (fast spiking shows a discontinuous f-I(stim relationship and a minimum threshold frequency. In a previous study of a hippocampal neuron model, we demonstrated that its dynamics could be of both Type 1 and Type 2, depending on ion channel density. In the present study we analyse the effect of varying channel density on threshold firing frequency on two well-studied axon membranes, namely the frog myelinated axon and the squid giant axon. Moreover, we analyse the hippocampal neuron model in more detail. The models are all based on voltage-clamp studies, thus comprising experimentally measurable parameters. The choice of analysing effects of channel density modifications is due to their physiological and pharmacological relevance. We show, using bifurcation analysis, that both axon models display exclusively Type 2 dynamics, independently of ion channel density. Nevertheless, both models have a region in the channel-density plane characterized by an N-shaped steady-state current-voltage relationship (a prerequisite for Type 1 dynamics and associated with this type of dynamics in the hippocampal model. In summary, our results suggest that the hippocampal soma and the two axon membranes represent two distinct kinds of membranes; membranes with a channel-density dependent switching between Type 1 and 2 dynamics, and membranes with a channel-density independent dynamics. The difference between the two membrane types suggests functional differences, compatible with a more flexible role of the soma membrane than that of the axon membrane.

  14. Non-modal theory of the kinetic ion temperature gradient driven instability of plasma shear flows across the magnetic field

    Science.gov (United States)

    Mikhailenko, V. V.; Mikhailenko, V. S.; Lee, Hae June

    2016-06-01

    The temporal evolution of the kinetic ion temperature gradient driven instability and of the related anomalous transport of the ion thermal energy of plasma shear flow across the magnetic field is investigated analytically. This instability develops in a steady plasma due to the inverse ion Landau damping and has the growth rate of the order of the frequency when the ion temperature is equal to or above the electron temperature. The investigation is performed employing the non-modal methodology of the shearing modes which are the waves that have a static spatial structure in the frame of the background flow. The solution of the governing linear integral equation for the perturbed potential displays that the instability experiences the non-modal temporal evolution in the shearing flow during which the unstable perturbation becomes very different from a canonical modal form. It transforms into the non-modal structure with vanishing frequency and growth rate with time. The obtained solution of the nonlinear integral equation, which accounts for the random scattering of the angle of the ion gyro-motion due to the interaction of ions with ensemble of shearing waves, reveals similar but accelerated process of the transformations of the perturbations into the zero frequency structures. It was obtained that in the shear flow the anomalous ion thermal conductivity decays with time. It is a strictly non-modal effect, which originates from the temporal evolution of the shearing modes turbulence.

  15. ELIMED: a new hadron therapy concept based on laser driven ion beams

    Science.gov (United States)

    Cirrone, Giuseppe A. P.; Margarone, Daniele; Maggiore, Mario; Anzalone, Antonello; Borghesi, Marco; Jia, S. Bijan; Bulanov, Stepan S.; Bulanov, Sergei; Carpinelli, Massimo; Cavallaro, Salvatore; Cutroneo, Mariapompea; Cuttone, Giacomo; Favetta, Marco; Gammino, Santo; Klimo, Ondrej; Manti, Lorenzo; Korn, Georg; La Malfa, Giuseppe; Limpouch, Jiri; Musumarra, Agatino; Petrovic, Ivan; Prokupek, Jan; Psikal, Jan; Ristic-Fira, Aleksandra; Renis, Marcella; Romano, Francesco P.; Romano, Francesco; Schettino, Giuseppe; Schillaci, Francesco; Scuderi, Valentina; Stancampiano, Concetta; Tramontana, Antonella; Ter-Avetisyan, Sargis; Tomasello, Barbara; Torrisi, Lorenzo; Tudisco, Salvo; Velyhan, Andriy

    2013-05-01

    Laser accelerated proton beams have been proposed to be used in different research fields. A great interest has risen for the potential replacement of conventional accelerating machines with laser-based accelerators, and in particular for the development of new concepts of more compact and cheaper hadrontherapy centers. In this context the ELIMED (ELI MEDical applications) research project has been launched by INFN-LNS and ASCR-FZU researchers within the pan-European ELI-Beamlines facility framework. The ELIMED project aims to demonstrate the potential clinical applicability of optically accelerated proton beams and to realize a laser-accelerated ion transport beamline for multi-disciplinary user applications. In this framework the eye melanoma, as for instance the uveal melanoma normally treated with 62 MeV proton beams produced by standard accelerators, will be considered as a model system to demonstrate the potential clinical use of laser-driven protons in hadrontherapy, especially because of the limited constraints in terms of proton energy and irradiation geometry for this particular tumour treatment. Several challenges, starting from laser-target interaction and beam transport development up to dosimetry and radiobiology, need to be overcome in order to reach the ELIMED final goals. A crucial role will be played by the final design and realization of a transport beamline capable to provide ion beams with proper characteristics in terms of energy spectrum and angular distribution which will allow performing dosimetric tests and biological cell irradiation. A first prototype of the transport beamline has been already designed and other transport elements are under construction in order to perform a first experimental test with the TARANIS laser system by the end of 2013. A wide international collaboration among specialists of different disciplines like Physics, Biology, Chemistry, Medicine and medical doctors coming from Europe, Japan, and the US is growing up

  16. Magnetically-Driven Accretion-Disk Winds and Ultra-Fast Outflows in PG1211+143

    CERN Document Server

    Fukumura, Keigo; Kazanas, Demosthenes; Shrader, Chris; Behar, Ehud; Contopoulos, Ioannis

    2015-01-01

    We present a study of X-ray ionization of magnetohydrodynamic (MHD) accretion-disk winds in an effort to constrain the physics underlying the highly-ionized ultra-fast outflows (UFOs) inferred by X-ray absorbers often detected in various sub-classes of Seyfert active galactic nuclei (AGNs). Our primary focus is to show that magnetically-driven outflows are indeed physically plausible candidates for the observed outflows accounting for the AGN absorption properties of the present X-ray spectroscopic observations. Employing a stratified MHD wind launched across the entire AGN accretion disk, we calculate its X-ray ionization and the ensuing X-ray absorption line spectra. Assuming an appropriate ionizing AGN spectrum, we apply our MHD winds to model the absorption features in an {\\it XMM-Newton}/EPIC spectrum of the narrow-line Seyfert, \\pg. We find, through identifying the detected features with Fe K$\\alpha$ transitions, that the absorber has a characteristic ionization parameter of $\\log (\\xi_c [erg~cm~s$^{-1}...

  17. Dynamics of Dusty Radiation Pressure Driven Shells: Fast Outflows from Galaxies, Star Clusters, Massive Stars, and AGN

    CERN Document Server

    Thompson, Todd A; Quataert, Eliot; Murray, Norman

    2014-01-01

    It is typically assumed that radiation pressure driven winds are accelerated to an asymptotic velocity of v_inf ~ v_esc, where v_esc is the escape velocity from the central source. We note that this is not the case for dusty shells. Instead, if the shell is initially optically-thick to the UV emission from the source of luminosity L, then there is a significant boost in v_inf that reflects the integral of the momentum absorbed by the shell as it is accelerated. For shells reaching a generalized Eddington limit, we show that v_inf ~ (4 R_UV L / M_sh c)^{1/2}, in both point-mass and isothermal-sphere potentials, where R_UV is the radius where the shell becomes optically-thin to UV photons, and M_sh is the mass of the shell. The asymptotic velocity significantly exceeds v_esc for typical parameters, and can explain the ~1000-2000 km/s outflows observed from rapidly star-forming galaxies and active galactic nuclei if their geometry is shell-like and if the surrounding halo has low gas density. Similarly fast shel...

  18. A 3 A sink/source current fast transient response low-dropout Gm driven linear regulator*

    Institute of Scientific and Technical Information of China (English)

    Chu Xiuqin; Li Qingwei; Lai Xinquan; Yuan Bing; LiYanming; Zhao Yongrui

    2011-01-01

    A 3 A sink/source Gm-driven CMOS low-dropout regulator (LDO), specially designed for low input voltage and low cost, is presented by utilizing the structure of a current mirror Gm (transconductance) driving technique, which provides high stability as well as a fast load transient response. The proposed LDO was fabricated by a 0.5μm standard CMOS process, and the die size is as small as 1.0 mm2. The proposed LDO dissipates 220 μA of quiescent current in no-load conditions and is able to deliver up to 3 A of load current. The measured results show that the output voltage can be resumed within 2 μs with a less than l mV overshoot and undershoot in the output current step from -1.8 to 1.8 A with a 0.1μs rising and falling time at three 10μF ceramic capacitors.

  19. Assessment of ion kinetic effects in shock-driven inertial confinement fusion implosions using fusion burn imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, M. J., E-mail: mros@lle.rochester.edu; Séguin, F. H.; Rinderknecht, H. G.; Zylstra, A. B.; Li, C. K.; Sio, H.; Johnson, M. Gatu; Frenje, J. A.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Amendt, P. A.; Wilks, S. C.; Pino, J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Atzeni, S. [Dipartimento SBAI, Università di Roma “La Sapienza” and CNISM, Via A. Scarpa 14-16, I-00161 Roma (Italy); Hoffman, N. M.; Kagan, G.; Molvig, K. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Glebov, V. Yu.; Stoeckl, C.; Seka, W.; Marshall, F. J. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); and others

    2015-06-15

    The significance and nature of ion kinetic effects in D{sup 3}He-filled, shock-driven inertial confinement fusion implosions are assessed through measurements of fusion burn profiles. Over this series of experiments, the ratio of ion-ion mean free path to minimum shell radius (the Knudsen number, N{sub K}) was varied from 0.3 to 9 in order to probe hydrodynamic-like to strongly kinetic plasma conditions; as the Knudsen number increased, hydrodynamic models increasingly failed to match measured yields, while an empirically-tuned, first-step model of ion kinetic effects better captured the observed yield trends [Rosenberg et al., Phys. Rev. Lett. 112, 185001 (2014)]. Here, spatially resolved measurements of the fusion burn are used to examine kinetic ion transport effects in greater detail, adding an additional dimension of understanding that goes beyond zero-dimensional integrated quantities to one-dimensional profiles. In agreement with the previous findings, a comparison of measured and simulated burn profiles shows that models including ion transport effects are able to better match the experimental results. In implosions characterized by large Knudsen numbers (N{sub K} ∼ 3), the fusion burn profiles predicted by hydrodynamics simulations that exclude ion mean free path effects are peaked far from the origin, in stark disagreement with the experimentally observed profiles, which are centrally peaked. In contrast, a hydrodynamics simulation that includes a model of ion diffusion is able to qualitatively match the measured profile shapes. Therefore, ion diffusion or diffusion-like processes are identified as a plausible explanation of the observed trends, though further refinement of the models is needed for a more complete and quantitative understanding of ion kinetic effects.

  20. 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

  1. Roles of Fast-Cyclotron and Alfven-Cyclotron Waves for the Multi-Ion Solar Wind

    CERN Document Server

    Xiong, Ming

    2012-01-01

    Using linear Vlasov theory of plasma waves and quasi-linear theory of resonant wave-particle interaction, the dispersion relations and the electromagnetic field fluctuations of fast and Alfven waves are studied for a low-beta multi-ion plasma in the inner corona. Their probable roles in heating and accelerating the solar wind via Landau and cyclotron resonances are quantified. We assume that (1) low-frequency Alfven and fast waves have the same spectral shape and the same amplitude of power spectral density; (2) these waves eventually reach ion cyclotron frequencies due to a turbulence cascade; (3) kinetic wave-particle interaction powers the solar wind. The existence of alpha particles in a dominant proton/electron plasma can trigger linear mode conversion between oblique fast-whistler and hybrid alpha-proton cyclotron waves. The fast-cyclotron waves undergo both alpha and proton cyclotron resonances. The alpha cyclotron resonance in fast-cyclotron waves is much stronger than that in Alfven-cyclotron waves. ...

  2. Status of the RF-driven H{sup −} ion source for J-PARC linac

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, H., E-mail: oguri.hidetomo@jaea.go.jp; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Asano, H.; Ueno, A.; Shibata, T. [J-PARC Center, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)

    2016-02-15

    For the upgrade of the Japan Proton Accelerator Research Complex linac beam current, a cesiated RF-driven negative hydrogen ion source was installed during the 2014 summer shutdown period, with subsequent operations commencing on September 29, 2014. The ion source has been successfully operating with a beam current and duty factor of 33 mA and 1.25% (500 μs and 25 Hz), respectively. The result of recent beam operation has demonstrated that the ion source is capable of continuous operation for approximately 1100 h. The spark rate at the beam extractor was observed to be at a frequency of less than once a day, which is an acceptable level for user operation. Although an antenna failure occurred during operation on October 26, 2014, no subsequent serious issues have occurred since then.

  3. Scaling of triple differential cross-sections for asymmetric (, 2) process on helium isoelectronic ions by fast electrons

    Indian Academy of Sciences (India)

    M K Srivastava

    2005-01-01

    A simple scaling law is obtained for asymmetric (, 2) process on helium isoelectronic ions by fast electrons. It is based on treating the targets as having one active electron moving in the effective Coulomb field of the atomic core with an effective charge ' = − 5/8. This effective charge is also used in the description of the scattered and ejected electrons. The model has been tested against other available (, 2) results on helium in asymmetric geometry. The scaling law is found to work reasonably well for fast incident electrons and becomes increasingly accurate as target increases.

  4. Recent developments in the Thomson Parabola Spectrometer diagnostic for laser-driven multi-species ion sources

    Science.gov (United States)

    Alejo, A.; Gwynne, D.; Doria, D.; Ahmed, H.; Carroll, D. C.; Clarke, R. J.; Neely, D.; Scott, G. G.; Borghesi, M.; Kar, S.

    2016-10-01

    Ongoing developments in laser-driven ion acceleration warrant appropriate modifications to the standard Thomson Parabola Spectrometer (TPS) arrangement in order to match the diagnostic requirements associated to the particular and distinctive properties of laser-accelerated beams. Here we present an overview of recent developments by our group of the TPS diagnostic aimed to enhance the capability of diagnosing multi-species high-energy ion beams. In order to facilitate discrimination between ions with same Z/A, a recursive differential filtering technique was implemented at the TPS detector in order to allow only one of the overlapping ion species to reach the detector, across the entire energy range detectable by the TPS. In order to mitigate the issue of overlapping ion traces towards the higher energy part of the spectrum, an extended, trapezoidal electric plates design was envisaged, followed by its experimental demonstration. The design allows achieving high energy-resolution at high energies without sacrificing the lower energy part of the spectrum. Finally, a novel multi-pinhole TPS design is discussed, that would allow angularly resolved, complete spectral characterization of the high-energy, multi-species ion beams.

  5. Cyclotron Resonances of Ions with Obliquely-Propagating Waves in Coronal Holes and the Fast Solar Wind

    Science.gov (United States)

    Hollweg, J. V.; Markovskii, S. A.

    2001-05-01

    UVCS/SOHO has provided observations of protons and ions in coronal holes which suggest the operation of ion-cyclotron heating and acceleration. Many models have concentrated on the interactions of particles with parallel-propagating ion-cyclotron waves. There is of course no reason to expect parallel propagation in the corona, so we consider here some consequences of oblique propagation. Following Stix (1992), we analytically calculate the energy absorbed by an ion moving in an obliquely-propagating electromagnetic wave. Resonances occur at harmonics of the gyro frequency, though we will show that the physical interpretations are quite different for electric field polarizations in, or perpendicular to, the plane containing k and Bo (k is wavenumber and Bo is the ambient magnetic field). Surprisingly, a resonance at the fundamental frequency can occur even if the wave is right-hand circularly polarized (i.e. opposite to the sense of the gyromotion). We suggest, therefore, that resonances with the fast/whistler branch, which are often overlooked, may play a role in the heating of ions and protons in coronal holes as long as the waves are oblique. We will discuss possible sources of such waves. We will also summarize other consequences of oblique propagation for the resonant heating of coronal holes and the origin of the fast solar wind. Stix, T.H., Waves in Plasmas, AIP, New York, 1992.

  6. Two Dual Ion Spectrometer Flight Units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS)

    Science.gov (United States)

    Adams, Mitzi

    2014-01-01

    Two Dual Ion Spectrometer flight units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS) have returned to MSFC for flight testing. Anticipated to begin on June 30, tests will ensue in the Low Energy Electron and Ion Facility of the Heliophysics and Planetary Science Office (ZP13), managed by Dr. Victoria Coffey of the Natural Environments Branch of the Engineering Directorate (EV44). The MMS mission consists of four identical spacecraft, whose purpose is to study magnetic reconnection in the boundary regions of Earth's magnetosphere.

  7. Measurement of inelasticities for charge correlated multiple ionization of Ne by fast C/sup 6 +/ ions

    Energy Technology Data Exchange (ETDEWEB)

    Schuch, R.; Datz, S.; Dittner, P.F.; Krause, H.F.; Miller, P.D.

    1987-01-01

    A description of measurements of inelasticities for multiple ionization in fast-single collisions is given for the example of 10 MeV C/sup 6 +/ ions with Ne atoms. The degree of multiple ionization was determined by time-of-flight of the recoil ions, extracted by an electric field in coincidence with the projectiles. Their energy loss for a given degree of multiple ionization was measured with a position-sensitive silicon detector in the focal plane of an Elbek magnetic spectrograph with an energy resolution of about 10/sup -4/.

  8. Design study of a fast spectrum zero-power reactor dedicated to source driven sub-critical experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mercatali, L.; Serikov, A. [Forschungszentrum Karlsruhe, Institute for Neutron Physics and Reactor Technology, P.O. Box 3640, 76021 Karlsruhe (Germany); Baeten, P.; Uyttenhove, W. [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Lafuente, A. [Univerisdad Politecnica de Madrid, 28006 Madrid (Spain); Teles, P. [Instituto Tecnologico e Nuclear, EN 10, 2680-953 Sacavem (Portugal)

    2010-09-15

    In the framework of the European P and T program (IFP6-EUROTRANS), the Generation of Uninterrupted Intense NEutrons pulses at the lead VEnus REactor (GUINEVERE) project consists of an Accelerator Driven System (ADS) that is composed by a fast lead simulated-cooled reactor operated in sub-critical conditions, coupled with an updated version of the GENEPI neutron generator previously used for the MUSE experiments. The GUINEVERE facility aims at developing and improving different techniques for the reactivity monitoring of sub-critical ADS's. As such, the GUINEVERE project will comprise a series of major experiments that will be performed in the near future. The GUINEVERE facility will be located at the VENUS light water moderated research reactor at the SCK-CEN site of Mol (Belgium), which needs to be modified in order to accommodate a completely different and new type of core. A series of constraints were taken into account in the technical design of the GUINEVERE core, in order to properly conjugate the technical feasibility of this facility and the necessity to comply with the envisioned experimental program and its associated scientific outcome. The complete design study of the GUINEVERE core is the subject of this paper. The final design of the fuel assemblies, safety and control rods is provided. Also, the critical core configuration, to be used as reference for absolute reactivity measurements, is presented along with its associated reactor physics parameters, calculated by means of Monte Carlo methodologies. Finally, for licensing purposes, the GUINEVERE facility must satisfy the required nuclear safety criteria of the Belgian safety authorities, and in this paper, an overview of the safety analysis that has been performed with regard to the core physics, thermal assessment and shielding issues is also provided. (author)

  9. Proton and He2+ Temperature Anisotropies in the Solar Wind Driven by Ion Cyclotron Waves

    Institute of Scientific and Technical Information of China (English)

    Quan-Ming Lu; Shui Wang

    2005-01-01

    We carried out one-dimensional hybrid simulations of resonant scattering of protons and He2+ ions by ion cyclotron waves in an initially homogeneous,collisionless and magnetized plasma. The initial ion cyclotron waves have a power spectrum and propagate both outward and inward. Due to the resonant interaction with the protons and He2+ ions, the wave power will be depleted in the resonance region. Both the protons and He2+ ions can be resonantly heated in the direction perpendicular to the ambient magnetic field and leading to anisotropic velocity distributions, with the anisotropy higher for the He2+ ions than for the protons.At the same time, the anisotropies of the protons and He2+ ions are inversely correlated with the plasma β||p = 87πnpkBT||p/B20, consistent with the prediction of the quasilinear theory (QLT).

  10. Energy exchange via multi-species streaming in laser-driven ion acceleration

    Science.gov (United States)

    King, M.; Gray, R. J.; Powell, H. W.; Capdessus, R.; McKenna, P.

    2017-01-01

    Due to the complex electron dynamics and multiple ion acceleration mechanisms that can take place in the interaction of an ultra-intense laser pulse with a thin foil, it is possible for multiple charged particle populations to overlap in space with varying momentum distributions. In certain scenarios this can drive streaming instabilities such as the relativistic Buneman instability and the ion-ion acoustic instability. The potential for such instabilities to occur are demonstrated using particle-in-cell simulations. It is shown that if a population of ions can be accelerated such that it can propagate through other slowly expanding ion populations, energy exchange can occur via the ion-ion acoustic instability.

  11. The response of a fast scintillator screen (YAP:Ce) to low energy ions (0-40 keV) and its use to detect fast-ion-loss in stellarator TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Martínez, M., E-mail: marcos.martinez@externos.ciemat.es [Universidad Carlos III de Madrid, Leganés (Spain); Zurro, B.; Baciero, A.; Jiménez-Rey, D.; Malo, M. [Laboratorio Nacional de Fusión, CIEMAT, Madrid (Spain); Tribaldos, V. [Departamento de Física, Universidad Carlos III de Madrid, Leganés (Spain); Crespo, M. T.; Muñoz, D. [Laboratorio de Metrología de Radiaciones Ionizantes, CIEMAT, Madrid (Spain)

    2016-11-15

    A systematic study of scintillation materials was undertaken to improve the time resolution of the fast ion diagnostic currently installed at TJ-II stellarator. It was found that YAP:Ce (formula YAlO{sub 3}:Ce, Yttrium Aluminum Perovskite doped with Cerium) ionoluminescence offers better sensitivity and time response compared to the standard detector material, SrGa{sub 2}S{sub 4}:Eu (TG-Green), currently used in TJ-II. A comparison between both materials was carried out by irradiating them with H{sup +} ions of up to 40 keV using a dedicated laboratory setup. It is found that for the low energy ions of interest at TJ-II, YAP:Ce offers 20 times higher sensitivity than TG-Green and much faster decay time, 27 ns versus 540 ns. It is expected that the use of YAP:Ce in combination with a faster data acquisition and an ion counting software as part of the TJ-II ion luminescent probe will provide 20 times faster data on ion loss.

  12. The response of a fast scintillator screen (YAP:Ce) to low energy ions (0-40 keV) and its use to detect fast-ion-loss in stellarator TJ-II

    Science.gov (United States)

    Martínez, M.; Zurro, B.; Baciero, A.; Jiménez-Rey, D.; Tribaldos, V.; Malo, M.; Crespo, M. T.; Muñoz, D.

    2016-11-01

    A systematic study of scintillation materials was undertaken to improve the time resolution of the fast ion diagnostic currently installed at TJ-II stellarator. It was found that YAP:Ce (formula YAlO3:Ce, Yttrium Aluminum Perovskite doped with Cerium) ionoluminescence offers better sensitivity and time response compared to the standard detector material, SrGa2S4:Eu (TG-Green), currently used in TJ-II. A comparison between both materials was carried out by irradiating them with H+ ions of up to 40 keV using a dedicated laboratory setup. It is found that for the low energy ions of interest at TJ-II, YAP:Ce offers 20 times higher sensitivity than TG-Green and much faster decay time, 27 ns versus 540 ns. It is expected that the use of YAP:Ce in combination with a faster data acquisition and an ion counting software as part of the TJ-II ion luminescent probe will provide 20 times faster data on ion loss.

  13. EFDA Task TW6-TPDS-DIADEV deliverable 2: ITER fast ion collective scattering development of diagnostic components and techniques

    Energy Technology Data Exchange (ETDEWEB)

    Michelsen, S.; Bindslev, H.; Korsholm, S.B.; Leipold, F.; Meo, F.; Michelsen, P.K.; Nielsen, A.H.; Tsakadze, E.

    2009-12-15

    In 2003 the Risoe CTS group finished a feasibility study and a conceptual design of an ITER fast ion collective Thomson scattering system. The purpose of the CTS diagnostic is to measure the distribution function of fast ions in the plasma with particular interest in fusion alphas. The feasibility study demonstrated that the only system, which can fully meet the ITER measurement requirements for confined fusion alphas, is a 60 GHz system. The study showed that by using two powerful microwave sources (gyrotrons) of this frequency both on the low field side, and two antenna systems, one on the low field side and one on the high field side, it is possible to resolve the distribution function of fast ions both for perpendicular andvparallel velocities with good spatial and temporal resolution. The present workvconcerned a continuation of this work, and the following tasks were performed. 1) Optimisation of the design, considering the scattering geometries, variations in plasma profiles, magnetic equilibria etc. 2) Development of numerical codes for determination of the geometry of the antenna system on the high field side, including shapes and positions of mirrors and receiver horns. 3) A model experiment was set up in order to test and support the theoretical and numerical results. From the design studies various R and D issues critical to the viability of the CTS diagnostic on ITER were identified; the most urgent ones are addressed in the presented R and D tasks. (author)

  14. Physics with fast molecular-ion beams. Proceedings of workshop held at Argonne National Laboratory, August 20-21, 1979. [Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Gemmell, D.S. (ed.)

    1979-01-01

    The Workshop on Physics with Fast Molecular-Ion Beams was held in the Physics Division, Argonne National Laboratory on August 20 and 21, 1979. The meeting brought together representatives from several groups studying the interactions of fast (MeV) molecular-ion beams with matter. By keeping the Workshop program sharply focussed on current work related to the interactions of fast molecular ions, it was made possible for the participants to engage in vigorous and detailed discussions concerning such specialized topics as molecular-ion dissociation and transmission, wake effects, ionic charge states, cluster stopping powers, beam-foil spectroscopy, electron-emissions studies with molecular-ion beams, and molecular-ion structure determinations.

  15. Temperature dynamics and velocity scaling laws for interchange driven, warm ion plasma filaments

    Science.gov (United States)

    Olsen, Jeppe; Madsen, Jens; Nielsen, Anders Henry; Rasmussen, Jens Juul; Naulin, Volker

    2016-04-01

    The influence of electron and ion temperature dynamics on the radial convection of isolated structures in magnetically confined plasmas is investigated by means of numerical simulations. It is demonstrated that the maximum radial velocity of these plasma blobs roughly follows the inertial velocity scaling, which is proportional to the ion acoustic speed times the square root of the filament particle density times the sum of the electron and ion temperature perturbations. Only for small blobs the cross field convection does not follow this scaling. The influence of finite Larmor radius effects on the cross-field blob convection is shown not to depend strongly on the dynamical ion temperature field. The blob dynamics of constant finite and dynamical ion temperature blobs is similar. When the blob size is on the order of 10 times the ion Larmor radius the blobs stay coherent and decelerate slowly compared to larger blobs which dissipate faster due to fragmentation and turbulent mixing.

  16. Diagnostics of Fast Axial Ions Produced in Deuterium Gas-Puff Z-Pinch

    Science.gov (United States)

    Rezac, K.; Klir, D.; Cikhardt, J.; Kubes, P.; Sila, O.; Kravarik, J.; Shishlov, A. V.; Labetsky, A. Yu.; Cherdizov, R. K.; Ratakhin, N. A.; Orcikova, H.; Turek, K.; Dudkin, N.; Padalko, V. N.; GIT-12 Team

    2016-10-01

    An unexpected advantage of some Z-pinch configurations is a possibility of an acceleration of ions to high energies. One of these configurations is a deuterium gas-puff with outer plasma shell, where hydrogen ions with energies up to 40 MeV has been observed during Z-pinch experiments on the GIT-12 generator since 2013. During the recent campaign in 2016, the source of high energetic ions and also parameters of ion pulses have been studied by various in-chamber diagnostics in 24 experimental shots on the current level below 3 MA. Principal aims were (i) to find a spatial distribution of ion sources, (ii) localization of ion sources on the z-axis and (iii) determine the ion energy spectra by an unfold technique. All of these has been done with the help of a new diagnostic setup consists of an ion pinhole camera, an ion 3-pinhole camera, a multi-pinhole camera and a detector of spatial ion beam profile. The ion diagnostics contained stacks with various absorbers, CR-39 track detectors, HD-V2 and EBT-3 radio-chromic films. One more aim, (iv) the study of a difference in production time of axial ion pulses with off-axis pulses, were accomplished by LiF samples and nTOF signals. This work was supported by the projects GACR 16-07036S, MSMT LD14089, CTU. SGS16/223/OHK3/3T/13, IAEA RC17088.

  17. Stability of current-driven electrostatic waves in a magnetized and collisional negative ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Venugopal, Chandu; Varghese, Anu; S, Jyothi [School of Pure and Applied Physics, Mahatma Gandhi University, Priyadarshini Hills, Kottayam 686 560, Kerala (India); Issac, Molly [Department of Physics, All Saints' College, Thiruvananthapuram 695 007, Kerala (India); Renuka, G [Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram 695 581, Kerala (India)], E-mail: cvgmgphys@yahoo.co.in

    2008-10-15

    The stability of electrostatic waves, propagating nearly parallel to a uniform external magnetic field, is studied in a fully ionized, collisional plasma of positive and negative ions and a field-aligned current of drifting electrons. Expressions have been derived for the dispersion relation and growth rate using fluid theory and retaining the collisional and conductivity terms for the electrons. The plasma can, in general, support two modes, which have frequencies that are a composite of the ion acoustic and ion gyro frequencies. The growth rate of the modes increases with increasing drift velocities of the electrons and decreases with increasing negative ion densities.

  18. Construction of Insulin 18-mer Nanoassemblies Driven by Coordination to Iron(II) and Zinc(II) Ions at Distinct Sites

    DEFF Research Database (Denmark)

    Munch, Henrik K.; Nygaard, Jesper; Christensen, Niels Johan;

    2016-01-01

    coordination with two different metal ions. Selective attachment of an abiotic 2,2′-bipyridine (bipy) ligand to HI, yielding HI–bipy, enabled ZnII-binding hexamers to SA into trimers of hexamers, [[HI–bipy]6]3, driven by octahedral coordination to a FeII ion. The structures were studied in solution by small...

  19. Development of the scintillator-based probe for fast-ion losses in the HL-2A tokamak

    Science.gov (United States)

    Zhang, Y. P.; Liu, Yi; Luo, X. B.; Isobe, M.; Yuan, G. L.; Liu, Y. Q.; Hua, Y.; Song, X. Y.; Yang, J. W.; Li, X.; Chen, W.; Li, Y.; Yan, L. W.; Song, X. M.; Yang, Q. W.; Duan, X. R.

    2014-05-01

    A new scintillator-based lost fast-ion probe (SLIP) has been developed and operated in the HL-2A tokamak [L. W. Yan, X. R. Duan, X. T. Ding, J. Q. Dong, Q. W. Yang, Yi Liu, X. L. Zou, D. Q. Liu, W. M. Xuan, L. Y. Chen, J. Rao, X. M. Song, Y. Huang, W. C. Mao, Q. M. Wang, Q. Li, Z. Cao, B. Li, J. Y. Cao, G. J. Lei, J. H. Zhang, X. D. Li, W. Chen, J. Chen, C. H. Cui, Z. Y. Cui, Z. C. Deng, Y. B. Dong, B. B. Feng, Q. D. Gao, X. Y. Han, W. Y. Hong, M. Huang, X. Q. Ji, Z. H. Kang, D. F. Kong, T. Lan, G. S. Li, H. J. Li, Qing Li, W. Li, Y. G. Li, A. D. Liu, Z. T. Liu, C. W. Luo, X. H. Mao, Y. D. Pan, J. F. Peng, Z. B. Shi, S. D. Song, X. Y. Song, H. J. Sun, A. K. Wang, M. X. Wang, Y. Q. Wang, W. W. Xiao, Y. F. Xie, L. H. Yao, D. L. Yu, B. S. Yuan, K. J. Zhao, G. W. Zhong, J. Zhou, J. C. Yan, C. X. Yu, C. H. Pan, Y. Liu, and the HL-2A Team, Nucl. Fusion 51, 094016 (2011)] to measure the losses of neutral beam ions. The design of the probe is based on the concept of the α-particle detectors on Tokamak Fusion Test Reactor (TFTR) using scintillator plates. The probe is capable of traveling across an equatorial plane port and sweeping the aperture angle rotationally with respect to the axis of the probe shaft by two step motors, in order to optimize the radial position and the collimator angle. The energy and the pitch angle of the lost fast ions can be simultaneously measured if the two-dimensional image of scintillation light intensity due to the impact of the lost fast ions is detected. Measurements of the fast-ion losses using the probe have been performed during HL-2A neutral beam injection discharges. The clear experimental evidence of enhanced losses of beam ions during disruptions has been obtained by means of the SLIP system. A detailed description of the probe system and the first experimental results are reported.

  20. CW/Pulsed H- ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

    Science.gov (United States)

    Peng, S. X.; Ren, H. T.; Xu, Y.; Zhang, T.; Zhang, A. L.; Zhang, J. F.; Zhao, J.; Guo, Z. Y.; Chen, J. E.

    2015-04-01

    Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H- beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H- source able to produce very intense H- beams with important variation of the duty factor[1]. Recently, a new version of 2.45 GHz microwave H- ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H- ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H- beam with rms emittance about 0.16 π.mm.mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H- ion beam at 35 keV with rms emittance about 0.2 π.mm.mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H- source body is ϕ116 mm × 124 mm, and the entire H- source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper.

  1. Fast ion conductivity in strained defect-fluorite structure created by ion tracks in Gd2Ti2O7

    Science.gov (United States)

    Aidhy, Dilpuneet S.; Sachan, Ritesh; Zarkadoula, Eva; Pakarinen, Olli; Chisholm, Matthew F.; Zhang, Yanwen; Weber, William J.

    2015-11-01

    The structure and ion-conducting properties of the defect-fluorite ring structure formed around amorphous ion-tracks by swift heavy ion irradiation of Gd2Ti2O7 pyrochlore are investigated. High angle annular dark field imaging complemented with ion-track molecular dynamics simulations show that the atoms in the ring structure are disordered, and have relatively larger cation-cation interspacing than in the bulk pyrochlore, illustrating the presence of tensile strain in the ring region. Density functional theory calculations show that the non-equilibrium defect-fluorite structure can be stabilized by tensile strain. The pyrochlore to defect-fluorite structure transformation in the ring region is predicted to be induced by recrystallization during a melt-quench process and stabilized by tensile strain. Static pair-potential calculations show that planar tensile strain lowers oxygen vacancy migration barriers in pyrochlores, in agreement with recent studies on fluorite and perovskite materials. In view of these results, it is suggested that strain engineering could be simultaneously used to stabilize the defect-fluorite structure and gain control over its high ion-conducting properties.

  2. Bioelectrochemical systems-driven directional ion transport enables low-energy water desalination, pollutant removal, and resource recovery.

    Science.gov (United States)

    Chen, Xi; Liang, Peng; Zhang, Xiaoyuan; Huang, Xia

    2016-09-01

    Bioelectrochemical systems (BESs) are integrated water treatment technologies that generate electricity using organic matter in wastewater. In situ use of bioelectricity can direct the migration of ionic substances in a BES, thereby enabling water desalination, resource recovery, and valuable substance production. Recently, much attention has been placed on the microbial desalination cells in BESs to drive water desalination, and various configurations have optimized electricity generation and desalination performance and also coupled hydrogen production, heavy metal reduction, and other reactions. In addition, directional transport of other types of charged ions can remediate polluted groundwater, recover nutrient, and produce valuable substances. To better promote the practical application, the use of BESs as directional drivers of ionic substances requires further optimization to improve energy use efficiency and treatment efficacy. This article reviews existing researches on BES-driven directional ion transport to treat wastewater and identifies a few key factors involved in efficiency optimization.

  3. Diagnostics of a negative hydrogen ion source based on a planar-coil inductively-driven discharge

    Energy Technology Data Exchange (ETDEWEB)

    Lishev, Stiliyan St.; Shivarova, Antonia P.; Iordanov, Dimitar I.; Todorov, Dimitar T.; Demerdzhiev, Angel P. [Faculty of Physics, Sofia University, 5 J. Bourchier Blvd., BG-1164 Sofia (Bulgaria)

    2013-02-08

    Recent activity on a volume-production negative-hydrogen-ion source with the design of a matrix of small-radius discharges inductively driven by a planar coil is reported. A single discharge of the matrix has been studied by employing probe-and laser-photodetachment diagnostics. The measurements have been carried out in the first - small-size - chamber of a two-chamber discharge vessel, with rf power introduced by a planar coil positioned on its front wall. The measured profiles of the negative ion density show strong axial dependence, with two maxima located at the positions corresponding to the maxima of the dc potential, where the maxima of the electron density are also located. The first maximum is in the vicinity of the rf power input and the second one is close to the interface between the two chambers of the discharge vessel.

  4. High-velocity, multistage, nozzled, ion driven wind generator and method of operation of the same adaptable to mesoscale realization

    Science.gov (United States)

    Dunn-Rankin, Derek (Inventor); Rickard, Matthew J. A. (Inventor)

    2011-01-01

    Gas flows of modest velocities are generated when an organized ion flux in an electric field initiates an ion-driven wind of neutral molecules. When a needle in ambient air is electrically charged to a potential sufficient to produce a corona discharge near its tip, such a gas flow can be utilized downstream of a ring-shaped or other permeable earthed electrode. In view of the potential practical applications of such devices, as they represent blowers with no moving parts, a methodology for increasing their flow velocities includes exploitation of the divergence of electric field lines, avoidance of regions of high curvature on the second electrode, control of atmospheric humidity, and the use of linear arrays of stages, terminating in a converging nozzle. The design becomes particularly advantageous when implemented in mesoscale domains.

  5. Coulomb driven energy boost of heavy ions for laser plasma acceleration

    CERN Document Server

    Braenzel, J; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M

    2014-01-01

    An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultra thin gold foils have been irradiated by an ultra short laser pulse at an intensity of $6\\times 10^{19}$ W/cm$^{2}$. Highly charged gold ions with kinetic energies up to $> 200$ MeV and a bandwidth limited energy distribution have been reached by using $1.3$ Joule laser energy on target. $1$D and $2$D Particle in Cell simulations show how a spatial dependence on the ions ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a varying charge density along the target normal and is capable of explaining the energy boost of highly charged ions, leading to a higher efficiency in laser acceleration of heavy ions.

  6. Toroidal mode driven by ion temperature gradients and magnetic-field curvature

    Energy Technology Data Exchange (ETDEWEB)

    Olla, P.

    1986-11-01

    The effect of magnetic-field curvature on the ion-mixing mode is studied in a collisionless-plasma regime. A simple plane model with an external gravity-simulating magnetic curvature is adopted. A dispersion relation which connects the ion-mixing mode to the ubiquitous mode is obtained. It is found that, within the limitations of the present local model, an inhomogeneous plasma can support fluctuations with frequencies larger than those expected in an analysis which disregards the effect of magnetic curvature. The instability threshold of this mode, which depends on the ion temperature gradient, is lowered. The effect of gravity on the ion response influences the quasi-linear ion heat transport.

  7. Calculation Of Change-Changing Cross Sections Of IONS Or Atoms Colliding With Fast IONS Using The Classical Trajectory Method

    Energy Technology Data Exchange (ETDEWEB)

    Kaganovich, I. D., Shnidman, Ariel, Mebane, Harrison, Davidson, R.C.

    2008-10-10

    Evaluation of ion-atom charge-changing cross sections is needed for many accelerator applications. A classical trajectory Monte Carlo (CTMC) simulation has been used to calculate ionization and charge exchange cross sections. For benchmarking purposes, an extensive study has been performed for the simple case of hydrogen and helium targets in collisions with various ions. Despite the fact that the simulation only accounts for classical mechanics, the calculations are comparable to experimental results for projectile velocities in the region corresponding to the vicinity of the maximum cross section. Shortcomings of the CTMC method for multielectron target atoms are discussed.

  8. First results with a surface conversion H ion source based on helicon wave mode-driven plasma discharge

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, Ollie A [Los Alamos National Laboratory; Geros, Ernest [Los Alamos National Laboratory; Rouleau, Gary [Los Alamos National Laboratory; Zaugg, Thomas J [Los Alamos National Laboratory

    2008-01-01

    The currently employed converter-type negative ion source at Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H{sup -} ion beams in a filament-driven discharge. The extracted H{sup -} beam current is limited by the achievable plasma density, which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which degrades the performance of the H{sup -} conversion surface. In order to overcome these limitations we have designed and tested a prototype of a surface conversion H{sup -} ion source, based on excitation of helicon plasma wave mode with an external antenna. The source has been operated with and without cesium injection. An H{sup -} beam current of over 12 mA has been transported through the low energy beam transport of the LANSCE ion source test stand. The results of these experiments and the effects of different source parameters on the extracted beam current are presented. The limitations of the source prototype are discussed and future improvements are proposed based on the experimental observations.

  9. RF-driven ion source with a back-streaming electron dump

    Science.gov (United States)

    Kwan, Joe; Ji, Qing

    2014-05-20

    A novel ion source is described having an improved lifetime. The ion source, in one embodiment, is a proton source, including an external RF antenna mounted to an RF window. To prevent backstreaming electrons formed in the beam column from striking the RF window, a back streaming electron dump is provided, which in one embodiment is formed of a cylindrical tube, open at one end to the ion source chamber and capped at its other end by a metal plug. The plug, maintained at the same electrical potential as the source, captures these backstreaming electrons, and thus prevents localized heating of the window, which due to said heating, might otherwise cause window damage.

  10. Nonlinear fast magnetoacoustic wave interaction with 2D magnetic X-points in the ion cyclotron range of frequencies

    CERN Document Server

    Threlfall, J W; De Moortel, I; McClements, K G; Arber, T D

    2012-01-01

    Context. This paper investigates the role of the Hall term in the propagation and dissipation of waves which interact with 2D magnetic X-points and considers the effect of the Hall term on the nature of the resulting reconnection. Aims. The goal is to determine how the evolution of a nonlinear fast magnetoacoustic wave pulse, and the behaviour of the oscillatory reconnection which results from the interaction of the pulse with a line-tied 2D magnetic X-point, is affected by the Hall term in the generalised Ohm's law. Methods. A Lagrangian remap shock-capturing code (Lare2d) is used to study the evolution of an initial fast magnetoacoustic wave annulus for a range of values of the ion skin depth (di) in resistive Hall MHD. A magnetic null-point finding algorithm is also used to locate and track the evolution of the multiple null-points that are formed in the system. Results. In general, the fast wave is coupled to a shear wave and, for finite di, to whistler and ion cyclotron waves. Dispersive whistler effects...

  11. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses

    KAUST Repository

    Zhang, Weipeng

    2013-11-11

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses.

  12. Kinetic effects on the transition to relativistic self-induced transparency in laser-driven ion acceleration

    Science.gov (United States)

    Siminos, Evangelos; Svedung Wettervik, Benjamin; Grech, Mickael; Fülöp, Tünde

    2016-10-01

    We study kinetic effects responsible for the transition to relativistic self-induced transparency in the interaction of a circularly-polarized laser-pulse with an overdense plasma and their relation to hole-boring and ion acceleration. It is shown, using particle-in-cell simulations and an analysis of separatrices in single-particle phase-space, that this transition is mediated by the complex interplay of fast electron dynamics and ion motion at the initial stage of the interaction. It thus depends on the ion charge-to-mass ratio and can be controlled by varying the laser temporal profile. Moreover, we find a new regime in which a transition from relativistic transparency to hole-boring occurs dynamically during the course of the interaction. It is shown that, for a fixed laser intensity, this dynamic transition regime allows optimal ion acceleration in terms of both energy and energy spread. This work was supported by the Knut and Alice Wallenberg Foundation (pliona project) and the European Research Council (ERC-2014-CoG Grant 647121).

  13. Volume-Averaged Model of Inductively-Driven Multicusp Ion Source

    Science.gov (United States)

    Patel, Kedar K.; Lieberman, M. A.; Graf, M. A.

    1998-10-01

    A self-consistent spatially averaged model of high-density oxygen and boron trifluoride discharges has been developed for a 13.56 MHz, inductively coupled multicusp ion source. We determine positive ion, negative ion, and electron densities, the ground state and metastable densities, and the electron temperature as functions of the control parameters: gas pressure, gas flow rate, input power and reactor geometry. Neutralization and fragmentation into atomic species are assumed for all ions hitting the wall. For neutrals, a wall recombination coefficient for oxygen atoms and a wall sticking coefficient for boron trifluoride (BF_3) and its dissociation products are the single adjustable parameters used to model the surface chemistry. For the aluminum walls of the ion source used in the Eaton ULE2 ion implanter, complete wall recombination of O atoms is found to give the best match to the experimental data for oxygen, whereas a sticking coefficient of 0.62 for all neutral species in a BF3 discharge was found to best match experimental data.

  14. New Insight into Metal Ion-Driven Catalysis of Nucleic Acids by Influenza PA-Nter.

    Directory of Open Access Journals (Sweden)

    Daria Kotlarek

    Full Text Available PA subunit of influenza RNA-dependent RNA polymerase deserves constantly increasing attention due to its essential role in influenza life cycle. N-terminal domain of PA (PA-Nter harbors endonuclease activity, which is indispensable in viral transcription and replication. Interestingly, existing literature reports on in vitro ion preferences of the enzyme are contradictory. Some show PA-Nter activity exclusively with Mn2+, whereas others report Mg2+ as a natural cofactor. To clarify it, we performed a series of experiments with varied ion concentrations and substrate type. We observed cleavage in the presence of both ions, with a slight preference for manganese, however PA-Nter activity highly depended on the amount of residual, co-purified ions. Furthermore, to quantify cleavage reaction rate, we applied fluorescence cross-correlation spectroscopy (FCCS, providing highly sensitive and real-time monitoring of single molecules. Using nanomolar ssDNA in the regime of enzyme excess, we estimated the maximum reaction rate at 0.81± 0.38 and 1.38± 0.34 nM/min for Mg2+ and Mn2+, respectively. However, our calculations of PA-Nter ion occupancy, based on thermodynamic data, suggest Mg2+ to be a canonical metal in PA-Nter processing of RNA in vivo. Presented studies constitute a step toward better understanding of PA-Nter ion-dependent activity, which will possibly contribute to new successful inhibitor design in the future.

  15. New Insight into Metal Ion-Driven Catalysis of Nucleic Acids by Influenza PA-Nter.

    Science.gov (United States)

    Kotlarek, Daria; Worch, Remigiusz

    2016-01-01

    PA subunit of influenza RNA-dependent RNA polymerase deserves constantly increasing attention due to its essential role in influenza life cycle. N-terminal domain of PA (PA-Nter) harbors endonuclease activity, which is indispensable in viral transcription and replication. Interestingly, existing literature reports on in vitro ion preferences of the enzyme are contradictory. Some show PA-Nter activity exclusively with Mn2+, whereas others report Mg2+ as a natural cofactor. To clarify it, we performed a series of experiments with varied ion concentrations and substrate type. We observed cleavage in the presence of both ions, with a slight preference for manganese, however PA-Nter activity highly depended on the amount of residual, co-purified ions. Furthermore, to quantify cleavage reaction rate, we applied fluorescence cross-correlation spectroscopy (FCCS), providing highly sensitive and real-time monitoring of single molecules. Using nanomolar ssDNA in the regime of enzyme excess, we estimated the maximum reaction rate at 0.81± 0.38 and 1.38± 0.34 nM/min for Mg2+ and Mn2+, respectively. However, our calculations of PA-Nter ion occupancy, based on thermodynamic data, suggest Mg2+ to be a canonical metal in PA-Nter processing of RNA in vivo. Presented studies constitute a step toward better understanding of PA-Nter ion-dependent activity, which will possibly contribute to new successful inhibitor design in the future.

  16. Synthesis and characterization of novel ion-imprinted polymeric nanoparticles for very fast and highly selective recognition of copper(II) ions.

    Science.gov (United States)

    Shamsipur, Mojtaba; Besharati-Seidani, Abbas; Fasihi, Javad; Sharghi, Hashem

    2010-12-15

    This work reports the preparation of new Cu(2+) ion-imprinted polymeric nanoparticles using 1-hydroxy-4-(prop-2'-enyloxy)-9,10-anthraquinone (AQ) as a vinylated chelating agent. The Cu(2+) ion found to form a stable 1:1 complex with AQ in methanol solution. The resulting Cu(2+)-AQ complex was copolymerized with ethyleneglycol dimethacrylate, as a cross-linking monomer, via precipitation polymerization method. The imprint copper ion was removed from the polymeric matrix using a 0.1 mol L(-1) HNO(3) solution. The Cu(2+)-imprinted polymeric nanoparticles were characterized by IR spectroscopy, scanning electron microscopy (SEM) and N(2) adsorption-desorption isotherms. The SEM micrographs showed colloidal nanoparticles of 60-100 nm in diameter and slightly irregular in shape. Optimum pH for maximum sorption was 7.0. Sorption and desorption of Cu(2+) ion on the IIP nanoparticles were quite fast and achieved completely over entire investigated time periods of 2-30 min. Maximum sorbent capacity and enrichment factor of the prepared IIP for Cu(2+) were 73.8 μmol g(-1) and 56.5, respectively. The relative standard deviation and limit of detection (C(LOD)=3S(b)/m) of the method were evaluated as 2.6% and 0.1 ng mL(-1), using inductively coupled plasma-atomic emission spectrometry, respectively. It was found that the imprinting technology results in increased affinity of the prepared material toward Cu(2+) ion over other metal ions with the same charge and close ionic radius. The relative standard deviations for six and twenty replicates with the same nanoparticles were found to be 1.7% and 2.1%, respectively. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. A rotating directional probe for the measurements of fast ion losses and plasma rotation at Tokamak Experiment for Technology Oriented Research.

    Science.gov (United States)

    Rack, M; Liang, Y; Jaegers, H; Assmann, J; Satheeswaran, G; Xu, Y; Pearson, J; Yang, Y; Denner, P; Zeng, L

    2013-08-01

    This work discusses a new directional probe designed for measurements of fast ion losses and the plasma rotation with a high angular resolution in magnetically confined plasmas. Directional and especially Mach probes are commonly used diagnostics for plasma flow measurements, and their applicability for the fast ion losses detection has been demonstrated. A limitation of static Mach probes is their low angular resolution. At the Tokamak Experiment for Technology Oriented Research, the angular resolution is strongly restricted by the finite number of available measurement channels. In a dynamic plasma, where instabilities can lead to local changes of the field line pitch-angle, plasma flow, or fast ion losses, a low angular resolution makes a precise data analysis difficult and reduces the quality of the measured data. The new probe design, the rotating directional probe, combines the features of early directional probes and Mach probes. It consists of two radially aligned arrays of nine Langmuir probe pins with each array facing opposite directions. During the measurement the probe head rotates along its axis to measure the ion saturation current from all directions. As a result, the rotating directional probe simultaneously provides an angular dependent plasma flow and fast ion losses measurement at different radial positions. Based on the angular dependent data, a precise determination of the current density is made. In addition, the simultaneous measurement of the ion saturation current at different radial positions allows for resolving radially varying field line pitch-angles and identifying the radial dynamic of processes like fast ion losses.

  18. Ion Fast Ignition-Establishing a Scientific Basis for Inertial Fusion Energy --- Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Richard Burnite [General Atomics; Foord, Mark N. [Lawrence Livermore National Laboratory; Wei, Mingsheng [General Atomics; Beg, Farhat N. [University of California, San Diego; Schumacher, Douglass W. [The Ohio State University

    2013-10-31

    The Fast Ignition (FI) Concept for Inertial Confinement Fusion (ICF) has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy reactors. FI differs from conventional ?central hot spot? (CHS) target ignition by decoupling compression from heating: using a laser (or heavy ion beam or Z pinch) drive pulse (10?s of nanoseconds) to create a dense fuel and a second, much shorter (~10 picoseconds) high intensity pulse to ignite a small volume within the dense fuel. The compressed fuel is opaque to laser light. The ignition laser energy must be converted to a jet of energetic charged particles to deposit energy in the dense fuel. The original concept called for a spray of laser-generated hot electrons to deliver the energy; lack of ability to focus the electrons put great weight on minimizing the electron path. An alternative concept, proton-ignited FI, used those electrons as intermediaries to create a jet of protons that could be focused to the ignition spot from a more convenient distance. Our program focused on the generation and directing of the proton jet, and its transport toward the fuel, none of which were well understood at the onset of our program. We have developed new experimental platforms, diagnostic packages, computer modeling analyses, and taken advantage of the increasing energy available at laser facilities to create a self-consistent understanding of the fundamental physics underlying these issues. Our strategy was to examine the new physics emerging as we added the complexity necessary to use proton beams in an inertial fusion energy (IFE) application. From the starting point of a proton beam accelerated from a flat, isolated foil, we 1) curved it to focus the beam, 2) attached the foil to a superstructure, 3) added a side sheath to protect it from the surrounding plasma, and finally 4) studied the proton beam behavior as it passed through a protective end cap into plasma. We built up, as we proceeded

  19. Ion Fast Ignition-Establishing a Scientific Basis for Inertial Fusion Energy --- Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Richard Burnite [General Atomics; Foord, Mark N. [Lawrence Livermore National Laboratory; Wei, Mingsheng [General Atomics; Beg, Farhat N. [University of California, San Diego; Schumacher, Douglass W. [The Ohio State University

    2013-10-31

    The Fast Ignition (FI) Concept for Inertial Confinement Fusion (ICF) has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy reactors. FI differs from conventional ?central hot spot? (CHS) target ignition by decoupling compression from heating: using a laser (or heavy ion beam or Z pinch) drive pulse (10?s of nanoseconds) to create a dense fuel and a second, much shorter (~10 picoseconds) high intensity pulse to ignite a small volume within the dense fuel. The compressed fuel is opaque to laser light. The ignition laser energy must be converted to a jet of energetic charged particles to deposit energy in the dense fuel. The original concept called for a spray of laser-generated hot electrons to deliver the energy; lack of ability to focus the electrons put great weight on minimizing the electron path. An alternative concept, proton-ignited FI, used those electrons as intermediaries to create a jet of protons that could be focused to the ignition spot from a more convenient distance. Our program focused on the generation and directing of the proton jet, and its transport toward the fuel, none of which were well understood at the onset of our program. We have developed new experimental platforms, diagnostic packages, computer modeling analyses, and taken advantage of the increasing energy available at laser facilities to create a self-consistent understanding of the fundamental physics underlying these issues. Our strategy was to examine the new physics emerging as we added the complexity necessary to use proton beams in an inertial fusion energy (IFE) application. From the starting point of a proton beam accelerated from a flat, isolated foil, we 1) curved it to focus the beam, 2) attached the foil to a superstructure, 3) added a side sheath to protect it from the surrounding plasma, and finally 4) studied the proton beam behavior as it passed through a protective end cap into plasma. We built up, as we proceeded

  20. Analysis of slow- and fast-α band asymmetry during performance of a saccadic eye movement task: dissociation between memory- and attention-driven systems.

    Science.gov (United States)

    Sanfim, Antonio; Velasques, Bruna; Machado, Sergio; Arias-Carrión, Oscar; Paes, Flávia; Teixeira, Silmar; Santos, Joana Luz; Bittencourt, Juliana; Basile, Luis F; Cagy, Mauricio; Piedade, Roberto; Sack, Alexander T; Nardi, Antonio Egídio; Ribeiro, Pedro

    2012-01-15

    This study aimed at analyzing the relationship between slow- and fast-alpha asymmetry within frontal cortex and the planning, execution and voluntary control of saccadic eye movements (SEM), and quantitative electroencephalography (qEEG) was recorded using a 20-channel EEG system in 12 healthy participants performing a fixed (i.e., memory-driven) and a random SEM (i.e., stimulus-driven) condition. We find main effects for SEM condition in slow- and fast-alpha asymmetry at electrodes F3-F4, which are located over premotor cortex, specifically a negative asymmetry between conditions. When analyzing electrodes F7-F8, which are located over prefrontal cortex, we found a main effect for condition in slow-alpha asymmetry, particularly a positive asymmetry between conditions. In conclusion, the present approach supports the association of slow- and fast-alpha bands with the planning and preparation of SEM, and the specific role of these sub-bands for both, the attention network and the coordination and integration of sensory information with a (oculo)-motor response.

  1. Theory of ion transport with fast acid-base equilibrations in bioelectrochemical systems

    NARCIS (Netherlands)

    Dykstra, J.E.; Biesheuvel, P.M.; Bruning, H.; Heijne, ter A.

    2014-01-01

    Bioelectrochemical systems recover valuable components and energy in the form of hydrogen or electricity from aqueous organic streams. We derive a one-dimensional steady-state model for ion transport in a bioelectrochemical system, with the ions subject to diffusional and electrical forces. Since mo

  2. Pulse combustion reactor as a fast and scalable synthetic method for preparation of Li-ion cathode materials

    Science.gov (United States)

    Križan, Gregor; Križan, Janez; Dominko, Robert; Gaberšček, Miran

    2017-09-01

    In this work a novel pulse combustion reactor method for preparation of Li-ion cathode materials is introduced. Its advantages and potential challenges are demonstrated on two widely studied cathode materials, LiFePO4/C and Li-rich NMC. By exploiting the nature of efficiency of pulse combustion we have successfully established a slightly reductive or oxidative environment necessary for synthesis. As a whole, the proposed method is fast, environmentally friendly and easy to scale. An important advantage of the proposed method is that it preferentially yields small-sized powders (in the nanometric range) at a fast production rate of 2 s. A potential disadvantage is the relatively high degree of disorder of synthesized active material which however can be removed using a post-annealing step. This additional step allows a further tuning of materials morphology as shown and commented in some detail.

  3. Characteristics and dynamics of the boundary layer in RF-driven sources for negative hydrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Wimmer, Christian

    2014-10-16

    The design of the neutral beam injection system of the upcoming ITER fusion device is based on the IPP (Max-Planck-Institut fuer Plasmaphysik, Garching) prototype source for negative hydrogen ions. The latter consists of a driver, in which hydrogen (or deuterium) molecules are dissociated in a large degree in a hydrogen plasma; the plasma expands then towards the plasma grid, on which negative hydrogen ions are formed by conversion of atoms or positive ions by the surface process and are extracted in the following accompanied by the co-extraction of electrons via a three grid system. Electrons are removed out of the extracted beam prior full acceleration using deflection magnets, bending them onto the second grid. The thermal load limits the tolerable amount of co-extracted electrons. A magnetic filter field in the expansion chamber reduces the electron temperature and density, on the one hand in order to minimize the destruction process of negative hydrogen ions by electron collisions and on the other hand in order to reduce the co-extracted electron current density. Caesium is evaporated into the source for an effective production of negative hydrogen ions, lowering the work function of the plasma grid. Due to the high chemical reactivity of caesium, the high vacuum condition in the source and the plasma-wall interaction, complex redistribution processes of Cs take place in the ion source. The boundary layer is the plasma volume between the magnetic filter field and the plasma grid, in which the most important physics of the negative ion source takes place: the production of negative hydrogen ions at the plasma grid, their transport through the plasma and the following extraction. A deeper understanding of the plasma and Cs dynamics in the boundary layer is desirable in order to achieve a stable long-pulse operation as well as to identify possible future improvements. For this reason, the boundary layer of the prototype source has been characterized in this work

  4. Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions

    Science.gov (United States)

    Alejo, A.; Green, A.; Ahmed, H.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; McKenna, P.; Mirfayzi, S. R.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.; Kar, S.

    2016-09-01

    The most established route to create a laser-based neutron source is by employing laser accelerated, low atomic-number ions in fusion reactions. In addition to the high reaction cross-sections at moderate energies of the projectile ions, the anisotropy in neutron emission is another important feature of beam-fusion reactions. Using a simple numerical model based on neutron generation in a pitcher-catcher scenario, anisotropy in neutron emission was studied for the deuterium-deuterium fusion reaction. Simulation results are consistent with the narrow-divergence (∼ 70 ° full width at half maximum) neutron beam recently served in an experiment employing multi-MeV deuteron beams of narrow divergence (up to 30° FWHM, depending on the ion energy) accelerated by a sub-petawatt laser pulse from thin deuterated plastic foils via the Target Normal Sheath Acceleration mechanism. By varying the input ion beam parameters, simulations show that a further improvement in the neutron beam directionality (i.e. reduction in the beam divergence) can be obtained by increasing the projectile ion beam temperature and cut-off energy, as expected from interactions employing higher power lasers at upcoming facilities.

  5. Isochoric heating of solid gold targets with the PW-laser-driven ion beams

    Science.gov (United States)

    Steinke, Sven; Ji, Qing; Bulanov, Stepan; Barnard, John; Schenkel, Thomas; Esarey, Eric; Leemans, Wim

    2016-10-01

    We present an end-to-end simulation for isochoric heating of solid gold targets using ion beams produced with the BELLA PW laser at LBNL: (i) 2D Particle-In-Cell (PIC) simulations are applied to study the ion source characteristics of the PW laser-target interaction at the long focal length (f/#65) beamline at laser intensities of 5x1019W/cm2 at spot size of ω0 = 52 μm on a CH target. (ii) In order to transport the ion beams to an EMP-free environment, an active plasma lens will be used. This was modeled by calculating the Twiss parameters of the ion beam from the appropriate transport matrixes using the source parameters obtained from the PIC simulation. Space charge effects were considered as well. (iii) Hydrodynamic simulations indicate that these ion beams can isochorically heat a 1 mm3 gold target to the Warm Dense Matter state. This work was supported by Fusion Energy Science, and LDRD funding from Lawrence Berkeley National Laboratory, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

  6. EFDA Task TW6-TPDS-DIADEV deliverable 2: ITER Fast Ion Collective Scattering Development of diagnostic components and techniques

    DEFF Research Database (Denmark)

    Michelsen, S.; Bindslev, Henrik; Korsholm, Søren Bang;

    field side and one on the high field side, it is possible to resolve the distribution function of fast ions both for perpendicular and parallel velocities with good spatial and temporal resolution. The present work concerned a continuation of this work, and the following tasks were performed. 1...... experiment was set up in order to test and support the theoretical and numerical results. From the design studies various R&D issues critical to the viability of the CTS diagnostic on ITER were identified; the most urgent ones are addressed in the presented R&D tasks....

  7. Fast ion induced shearing of 2D Alfvén eigenmodes measured by electron cyclotron emission imaging.

    Science.gov (United States)

    Tobias, B J; Classen, I G J; Domier, C W; Heidbrink, W W; Luhmann, N C; Nazikian, R; Park, H K; Spong, D A; Van Zeeland, M A

    2011-02-18

    Two-dimensional images of electron temperature perturbations are obtained with electron cyclotron emission imaging (ECEI) on the DIII-D tokamak and compared to Alfvén eigenmode structures obtained by numerical modeling using both ideal MHD and hybrid MHD-gyrofluid codes. While many features of the observations are found to be in excellent agreement with simulations using an ideal MHD code (NOVA), other characteristics distinctly reveal the influence of fast ions on the mode structures. These features are found to be well described by the nonperturbative hybrid MHD-gyrofluid model TAEFL.

  8. High-resolution X-ray study of the multiple ionization of Pd atoms by fast oxygen ions

    OpenAIRE

    Czarnota, M.; Banaś, D; Berset, Michel; Chmielewska, D; Dousse, Jean-Claude; Hoszowska, Joanna; Maillard, Yves-Patrick; Mauron, Olivier; Pajek, M.; Polasik, M.; Raboud, Pierre-Alexandre; Rzadkiewicz, J.; Słabkowska, K.; Sujkowski, Z.

    2010-01-01

    The multiple ionization of the L- and M-shells of Pd by fast oxygen ions has been studied by measuring with high-resolution the satellite structures of the Lα1,2 X-ray transitions. Relativistic multi-configuration Dirac-Fock (MCDF) calculations were used to interpret the complex X-ray spectrum, allowing to derive the number of L- and M-shell spectator vacancies at the moment of the X-ray emission. After correcting these numbers for the atomic vacancy rearrangement processes that take place pr...

  9. Scaling of cross-sections for asymmetric (, 3) process on helium-like ions by fast electrons

    Indian Academy of Sciences (India)

    M K Srivastava

    2004-11-01

    An approximate simple scaling law is obtained for asymmetric (, 3) process on helium-like ions for double ionization by fast electrons. It is based on the equation $(Z'^{3} /)$ exp$[−Z' (r_{1} + r_{2})]$, $Z' = Z − (5/16)$ for ground state wave function of helium- like ions and $Z'^{2}$ scaling of energies. The scaling law is found to work very well if the lower energy electron is ejected along the momentum transfer direction and the other one is ejected in the opposite direction. It also works quite well if this electron is ejected within about 90° of the momentum transfer direction with the other electron going in the opposite direction. The scaling law becomes increasingly accurate as the target nuclear charge and the energy increase.

  10. Application of a pulsed, RF-driven, multicusp source for low energy plasma immersion ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Wengrow, A.B.; Leung, K.N.; Perkins, L.T.; Pickard, D.S.; Rickard, M.; Williams, M.D. [Lawrence Berkeley Lab., CA (United States); Tucker, M. [Spectrum Sciences, Inc., Santa Clara, CA (United States)

    1996-06-01

    The multicusp ion source can produce large volumes of uniform, quiescent, high density plasmas. A plasma chamber suited for plasma immersion ion implantation (PIII) was readily made. Conventional PIII pulses the bias voltage applied to the substrate which is immersed in a CW mode plasma. Here, a method by which the plasma itself is pulsed was developed. Typically pulse lengths of 500 {mu}s are used and are much shorter than that of the substrate voltage pulse (5-15 ms). This approach, together with low gas pressures and low bias voltages, permits the constant energy implantation of an entire wafer simultaneously without glow discharge. Results show that this process can yield implant currents of up to 2.5 mA/cm{sup 2}; thus very short implant times can be achieved. Uniformity of the ion flux is also discussed. As this method can be scaled to any dimension, it can be made to handle any size wafer.

  11. Effect of temperature in cerium-ion-catalyzed bromate-driven oscillators

    Science.gov (United States)

    Nagy, Gabriella; Körös, Endre; Oftedal, Norunn; Tjelflaat, Kjetil; Ruoff, Peter

    1996-03-01

    The influence of substrate composition and initial reagent concentrations on activation energies in closed Ce-ion catalyzed Belousov-Zhabotinsky (BZ) reactions is reported. While changes in the initial concentration of organic substrate, bromate ion or sulfuric acid showed different changes in activation energies for the various organic substrate BZ systems, for all systems it was found that lowering the Ce-ion concentration leads to a significant decrease in the overall activation energy of the oscillator. When comparing the performance of a malonic acid oscillator run in a batch or in a continuous stirred flow reactor (CSTR), it was found that under CSTR conditions Q10 values may become as low as 1.3, while for the batch system the corresponding Q10 values are about 2.3.

  12. Ion waves driven by shear flow in a relativistic degenerate astrophysical plasma

    Indian Academy of Sciences (India)

    KHAN SHABBIR A; BAKHTIAR-UD-DIN; ILYAS MUHAMMAD; WAZIR ZAFAR

    2016-05-01

    We investigate the existence and propagation of low-frequency (in comparison to ion cyclotron frequency) electrostatic ion waves in highly dense inhomogeneous astrophysical magnetoplasma comprising relativistic degenerate electrons and non-degenerate ions. The dispersion equation is obtained by Fourier analysis under mean-field quantum hydrodynamics approximationfor various limits of the ratio of rest mass energy to Fermi energy of electrons, relevant to ultrarelativistic, weakly-relativistic and non-relativistic regimes. It is found that the system admits an oscillatory instability under certain condition in the presence of velocity shear parallel to ambient magnetic field. The dispersive role of plasma density and magnetic field is also discussed parametrically in the scenario of dense and degenerate astrophysical plasmas.

  13. Inductively driven surface-plasma negative ion source for N-NBI use (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Belchenko, Yu., E-mail: belchenko@inp.nsk.su; Abdrashitov, G.; Deichuli, P.; Ivanov, A.; Gorbovsky, A.; Kondakov, A.; Sanin, A.; Sotnikov, O.; Shikhovtsev, I. [Budker Institute of Nuclear Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2016-02-15

    The long-pulse surface-plasma source prototype is developed at Budker Institute of Nuclear Physics for negative-ion based neutral beam injector use. The essential source features are (1) an active temperature control of the ion-optical system electrodes by circulation of hot thermal fluid through the channels, drilled in the electrode bodies, (2) the concaved transverse magnetic field in the extraction and acceleration gaps, preventing the electrons trapping and avalanching, and (3) the directed cesium deposition via distribution tubes adjacent to the plasma grid periphery. The long term effect of cesium was obtained just with the single cesium deposition. The high voltage strength of ion-optical system electrodes was improved with actively heated electrodes. A stable H{sup −} beam with a current ∼1 A and energy 90 keV was routinely extracted and accelerated.

  14. An outlook of heavy ion driven plasma research at IMP-Lanzhou

    Science.gov (United States)

    Zhao, Yongtao; Xiao, Guoqing; Xu, Hushan; Zhao, Hongwei; Xia, Jiawen; Jin, Genming; Ma, Xinwen; Liu, Yong; Yang, Zhihu; Zhang, Pengming; Wang, Yuyu; Li, Deihui; Zhao, Huanyu; Zhan, Wenlong; Xu, Zhongfeng; Zhao, Di; Li, Fuli; Chen, Ximeng

    2009-01-01

    Since the successful completion of the cooling storage ring (CSR) project in China at the end of 2007, high qualitative heavy ion beams with energy ranging from keV to GeV/u have been available at the Heavy Ion Research Facility at Lanzhou (HIRFL). More than 10 9 1 GeV/u C 6+ particles or 10 8 235 MeV/u Xe particles can be stored in the CSR main-ring and extracted within hundred nano-seconds during the test running, the beam parameters will be improved in the coming years so that high energy density (HED) conditions could be achieved and investigated there. Recent scientific results from the experiments relevant to plasma research on HIRFL are summarized. Dense plasma research with intense heavy ion beams of CSR is proposed here.

  15. Nanoconfined LiBH4 as a Fast Lithium Ion Conductor

    DEFF Research Database (Denmark)

    Blanchard, Didier; Nale, Angeloclaudio; Sveinbjörnsson, Dadi Þorsteinn

    2015-01-01

    is associated with a fraction of the confined borohydride that shows no phase transition, and most likely located close to the interface with the SiO2 pore walls. These results point to a new strategy to design low-temperature ion conducting solids for application in all solid-state lithium ion batteries, which......Designing new functional materials is crucial for the development of efficient energy storage and conversion devices such as all solid-state batteries. LiBH 4 is a promising solid electrolyte for Li-ion batteries. It displays high lithium mobility, although only above 110 °C at which a transition...

  16. Visualization and Interpretation of Attosecond Electron Dynamics in Laser-Driven Hydrogen Molecular Ion using Bohmian Trajectories

    CERN Document Server

    Takemoto, Norio

    2010-01-01

    We analyze the attosecond electron dynamics in hydrogen molecular ion driven by an external intense laser field using ab-initio numerical simulations of the corresponding time-dependent Schr{\\"{o}}dinger equation and Bohmian trajectories. To this end, we employ a one-dimensional model of the molecular ion in which the motion of the protons is frozen. The results of the Bohmian trajectory calculations do agree well with those of the ab-initio simulations and clearly visualize the electron transfer between the two protons in the field. In particular, the Bohmian trajectory calculations confirm the recently predicted attosecond transient localization of the electron at one of the protons and the related multiple bunches of the ionization current within a half cycle of the laser field. Further analysis based on the quantum trajectories shows that the electron dynamics in the molecular ion can be understood via the phase difference accumulated between the Coulomb wells at the two protons. Modeling of the dynamics ...

  17. Evaluation of observable phase space by fast ion loss detector by calculating particle orbits in consideration of plasma facing components and three dimensional magnetic field

    Science.gov (United States)

    Shinohara, Kouji; Kim, Junghee; Kim, Jun Young; Rhee, Tongnyeol

    2016-11-01

    The orbits of lost ions can be calculated from the information obtained by a fast ion loss detector (FILD). The orbits suggest a source of the lost fast ions in a phase space. However, it is not obvious whether an observable set of orbits, or phase space, of a FILD appropriately covers the region of interest to be investigated since the observable phase space can be affected by plasma facing components (PFCs) and a magnetic configuration. A tool has been developed to evaluate the observable phase space of FILD diagnostic by calculating particle orbits by taking the PFCs and 3D magnetic field into account.

  18. Fast- and slow-wave heating of ion cyclotron range of frequencies in the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Mutoh, T.; Kumazawa, R.; Seki, T. [and others

    2000-11-01

    Wave-heating at the fundamental ion-cyclotron frequency was applied to a hydrogen plasma in the Large Helical Device (LHD) over a range of plasma densities from 0.2-8x10{sup 19} m{sup -3}. Substantial heating was observed for all densities. In the low-density plasma (less than 0.4x10{sup 19} m{sup -3}) ion-cyclotron-wave (shear Alfven wave) heating was effective. For high-density plasmas, a fast-wave should be excited, and in this case also, effective heating was observed with the presence of the NBI beam component. The wave damping mechanism may be attributed to the finite gyro-radius effect on beam ions by the right-handed polarized wave. The experimental results were compared with an analysis using the full-wave code. The heating performance was a little worse than that of the usual two-ion hybrid-heating mode. (author)

  19. Actin filaments as the fast pathways for calcium ions involved in auditory processes

    Indian Academy of Sciences (India)

    Miljko V Sataric; Dalibor L Sekulic; Bogdan M Sataric

    2015-09-01

    We investigated the polyelectrolyte properties of actin filaments which are in interaction with myosin motors, basic participants in mechano-electrical transduction in the stereocilia of the inner ear. Here, we elaborated a model in which actin filaments play the role of guides or pathways for localized flow of calcium ions. It is well recognized that calcium ions are implicated in tuning of actin-myosin cross-bridge interaction, which controls the mechanical property of hair bundle. Actin filaments enable much more efficient delivery of calcium ions and faster mechanism for their distribution within the stereocilia. With this model we were able to semiquantitatively explain experimental evidences regarding the way of how calcium ions tune the mechanosensitivity of hair cells.

  20. Dynamics and control of fast ion crystal splitting in segmented Paul traps

    CERN Document Server

    Kaufmann, H; Schmiegelow, C T; Schmidt-Kaler, F; Poschinger, U G

    2014-01-01

    We theoretically investigate the process of splitting two-ion crystals in segmented Paul traps, i.e. the structural transition from two ions confined in a common well to ions confined in separate wells. The precise control of this process by application of suitable voltage ramps to the trap segments is non-trivial, as the harmonic confinement transiently vanishes during the process. This makes the ions strongly susceptible to background electric field noise, and to static offset fields in the direction of the trap axis. We analyze the reasons why large energy transfers can occur, which are impulsive acceleration, the presence of residual background fields and enhanced anomalous heating. For the impulsive acceleration, we identify the diabatic and adiabatic regimes, which are characterized by different scaling behavior of the energy transfer with respect to time. We propose a suitable control scheme based on experimentally accessible parameters. Simulations are used to verify both the high sensitivity of the s...

  1. High-resolution fast ion microscopy of single whole biological cells

    Science.gov (United States)

    Bettiol, Andrew A.; Mi, Zhaohong; Watt, Frank

    2016-12-01

    High-resolution microscopy techniques have become an essential tool in both biological and biomedical sciences, enabling the visualization of biological processes at cellular and subcellular levels. For many years, these imaging techniques utilized conventional optical microscopes including those with confocal facilities. However, the spatial resolutions achieved were largely limited to around 200 nm, as determined by the diffraction of light. To overcome this diffraction barrier, considerable scientific and technological effort has resulted in the development of super-resolution optical-based techniques, scanning probe microscopies, and also techniques utilizing charged particles (e.g., energetic electrons and ions) or high-energy photons (e.g., X-ray), which exhibit much shorter de Broglie wavelengths. Among the charged particle techniques, those utilizing mega-electron-volt (MeV) ion beams appear to have unique advantages primarily because MeV ions can penetrate through several microns of biological tissue (e.g., whole cells) with little deflection in their trajectories, and hence spatial resolutions are maintained while traversing the sample. Recently, we have witnessed the significant development of MeV ion beam focusing systems in reducing beam dimensions well below 100 nm, such that single whole cell imaging at 20 nm spatial resolutions is now possible. In this review, two super resolution imaging modalities that utilize MeV highly focused ion beams are discussed: Scanning Transmission Ion Microscopy (STIM), which images the areal density of cells and gives an insight into the cellular structure, and Proton/Helium-ion Induced Fluorescence Microcopy (P/HeIFM), which images the fluorescence emission of fluorescent markers and probes used as labels within the cells. This review hopes to demonstrate the potential of MeV ion microscopy, which is still in its infancy, and describe the simultaneous use of STIM and P/HeIFM as a new and powerful multifaceted

  2. Beam extraction from a laser-driven multicharged ion source (abstract)

    Science.gov (United States)

    Anderson, O. A.; Logan, B. Grant

    1998-02-01

    A newly proposed type of multicharged ion source has several potential advantages over existing types and a number of useful applications. The basic principle is that multiphoton absorption in an intense uniform laser focus can give multiple charge states of high purity (Ref. Reference 1). Thus, charge state separation downstream is simplified or made unnecessary. Another advantage is that large currents (hundreds of amperes) can be extracted. This type of source could be used for heavy-ion fusion drivers (see Ref. Reference 1) or storage rings. There are also industrial application such as materials processing. We describe conceptual design studies for several specific cases. For example, we discuss extraction and focusing of a 4.1 MV, 144 A beam of Xe16+ ions from an expanding plasma created by an intense laser. The maximum duration of the beam pulse is determined by the total charge in the plasma, while the practical pulse length is determined by the range of plasma radii over which good beam optics can be achieved. The initially diverging beam can be refocused to a small radius or made parallel by a combination of electrostatic and solenoid focusing. Our design studies are carried out first with an envelope code to determine the proper focusing parameters and then with a self-consistent particle code to optimize the beam quality. We present results from both codes and discuss several applications of this type of ion source.

  3. Temperature dynamics and velocity scaling laws for interchange driven, warm ion plasma filaments

    DEFF Research Database (Denmark)

    Olsen, Jeppe Miki Busk; Madsen, Jens; Nielsen, Anders Henry

    2016-01-01

    The influence of electron and ion temperature dynamics on the radial convection of isolated structures in magnetically confined plasmas is investigated by means of numerical simulations. It is demonstrated that the maximum radial velocity of these plasma blobs roughly follows the inertial velocit...

  4. Electrically driven ion separations and nanofiltration through membranes coated with polyelectrolyte multilayers

    Science.gov (United States)

    White, Nicholas

    Polyelectrolyte multilayer (PEM) films deposited using the layer-by-layer (LBL) method are attractive for their simple deposition, tailorable nature, scalability, and charge or size-based selectivity for solutes. This dissertation explores ion separations in electrodialysis (ED) and solute removal through nanofiltration with PEMs deposited on polymer membranes. ED membranes typically exhibit modest selectivities between monovalent and divalent ions. In contrast, this work shows that K+/Mg 2+ ED selectivities reach values >1000 when using Nafion 115 cation-exchange membranes coated with multilayer poly(4-styrenesulfonate) (PSS)/protonated poly(allylamine) (PAH) films. For comparison, the corresponding K+ /Mg2+ selectivity of bare Nafion 115 is 20,000, presumably because the applied current is below the limiting value for K+ and H+ transport is negligible at this high K+ concentration. The high selectivities of these membranes may enable electrodialysis applications such as purification of salts that contain divalent or trivalent ions. The high ED selectivities of (PAH/PSS)5PAH-coated Nafion membranes translate to separations with Li+/Co2+ and K +/La3+. Even with adsorption of only 3 polyelectrolyte layers, Nafion membranes exhibit a Li+/Co2+ selectivity >23. However, the resistance to monovalent-ion passage does not decrease significantly with fewer polyelectrolyte layers. At overlimiting currents, hydroxides from water splitting form insoluble metal hydroxides to foul the membrane. With 0.1 M source-phase salt concentrations, transference numbers for monovalent cations approach unity and selectivities are >5000 because the diffusion-limited K+ or Li+ currents exceed the applied current. However, ED selectivities gradually decline with time. Thus, future research should aim to increase membrane stability and limiting currents to fully exploit the remarkable selectivity of these membranes. PEMs deposited on commercial ultrafiltration (UF) membranes also show high

  5. Generation of quasi-monoenergetic heavy ion beams via staged shock wave acceleration driven by intense laser pulses in near-critical plasmas

    Science.gov (United States)

    Zhang, W. L.; Qiao, B.; Shen, X. F.; You, W. Y.; Huang, T. W.; Yan, X. Q.; Wu, S. Z.; Zhou, C. T.; He, X. T.

    2016-09-01

    Laser-driven ion acceleration potentially offers a compact, cost-effective alternative to conventional accelerators for scientific, technological, and health-care applications. A novel scheme for heavy ion acceleration in near-critical plasmas via staged shock waves driven by intense laser pulses is proposed, where, in front of the heavy ion target, a light ion layer is used for launching a high-speed electrostatic shock wave. This shock is enhanced at the interface before it is transmitted into the heavy ion plasmas. Monoenergetic heavy ion beam with much higher energy can be generated by the transmitted shock, comparing to the shock wave acceleration in pure heavy ion target. Two-dimensional particle-in-cell simulations show that quasi-monoenergetic {{{C}}}6+ ion beams with peak energy 168 MeV and considerable particle number 2.1 × {10}11 are obtained by laser pulses at intensity of 1.66 × {10}20 {{W}} {{cm}}-2 in such staged shock wave acceleration scheme. Similarly a high-quality {{Al}}10+ ion beam with a well-defined peak with energy 250 MeV and spread δ E/{E}0=30 % can also be obtained in this scheme.

  6. Fast-ignition heavy-ion fusion target by jet impact

    Energy Technology Data Exchange (ETDEWEB)

    Velarde, P. [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, C/ Jose Gutierrez Abascal, 2. 28006 Madrid (Spain)]. E-mail: pedro@din.upm.es; Ogando, F. [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, C/ Jose Gutierrez Abascal, 2. 28006 Madrid (Spain); Universidad Nacional de Educacion a Distancia (Spain); Eliezer, S. [Soreq Nuclear Research Center (Israel); Martinez-Val, J.M. [Soreq Nuclear Research Center (Israel)

    2005-05-21

    A new target design for HIF, based on the fast-ignition principles, is proposed. Unlike the previous designs proposed so far, in this case just one energy source is needed to drive the whole process to ignition. The ultra-fast deposition of energy onto the compressed core is produced in this case by hypervelocity jets generated during the process. The collision of jets converts their kinetic energy into thermal energy of the nuclear fuel, which is expected to produce ignition under proper design. The process is studied in this paper, describing its most relevant features like jet production and later collision.

  7. Characterization of synthetic dyes by comprehensive two-dimensional liquid chromatography combining ion-exchange chromatography and fast ion-pair reversed-phase chromatography.

    Science.gov (United States)

    Pirok, Bob W J; Knip, Jitske; van Bommel, Maarten R; Schoenmakers, Peter J

    2016-03-04

    In the late 19th century, newly invented synthetic dyes rapidly replaced the natural dyes on the market. The characterization of mixtures of these so-called early synthetic dyes is complicated through the occurrence of many impurities and degradation products. Conventional one-dimensional liquid chromatography does not suffice to obtain fingerprints with sufficient resolution and baseline integrity. Comprehensive two-dimensional liquid chromatography (LC×LC) is employed in this study, with ion-exchange chromatography in the first dimension and fast ion-pair liquid chromatography in the second. Retention in the first dimension is largely determined by the number of charges, while the selection of a small ion-pair reagent (tetramethylammonium hydroxide) in the second dimension causes retention to be largely determined by the molecular structure of the dye. As a result, there is a high degree of orthogonality of the two dimensions, similar to the values typically encountered in GC×GC. The proposed LC×LC method shows a theroretical peak capacity of about 2000 in an analysis time of about three hours. Clear, informative fingerprints are obtained that open a way to a more efficient characterization of dyes used in objects of cultural heritage.

  8. An aircraft-borne chemical ionization – ion trap mass spectrometer (CI-ITMS for fast PAN and PPN measurements

    Directory of Open Access Journals (Sweden)

    H. Schlager

    2011-02-01

    Full Text Available An airborne chemical ionization ion trap mass spectrometer instrument (CI-ITMS has been developed for tropospheric and stratospheric fast in-situ measurements of PAN (peroxyacetyl nitrate and PPN (peroxypropionyl nitrate. The first scientific deployment of the FASTPEX instrument (FASTPEX = Fast Measurement of Peroxyacyl nitrates took place in the Arctic during 18 missions aboard the DLR research aircraft Falcon, within the framework of the POLARCAT-GRACE campaign in the summer of 2008. The FASTPEX instrument is described and characteristic properties of the employed ion trap mass spectrometer are discussed. Atmospheric data obtained at altitudes of up to ~12 km are presented, from the boundary layer to the lowermost stratosphere. Data were sampled with a time resolution of 2 s and a 2σ detection limit of 25 pmol mol−1. An isotopically labelled standard was used for a permanent on-line calibration. For this reason the accuracy of the PAN measurements is better than ±10% for mixing ratios greater than 200 pmol mol−1. PAN mixing ratios in the summer Arctic troposphere were in the order of a few hundred pmol mol−1 and generally correlated well with CO. In the Arctic boundary layer and lowermost stratosphere smaller PAN mixing ratios were observed due to a combination of missing local sources of PAN precursor gases and efficient removal processes (thermolysis/photolysis. PPN, the second most abundant PAN homologue, was measured simultaneously. Observed PPN/PAN ratios range between ~0.03 and 0.3.

  9. Nuclear Structure and Nuclear Astrophysics Studies with Fast Heavy-Ion Beams

    Science.gov (United States)

    Motobayashi, Tohru

    Collaboration between France and Japan on studies with fast RI (radioactive isotope) beams and related technical developments started in 1980s, when the GANIL accelerators and RIKEN cyclotron complex started operation and RI beam production technique was developed. Several examples of collaboration on nuclear physics and nuclear astrophysics experiments including related technical development are discussed.

  10. Fine-tuning to minimize emittances of J-PARC RF-driven H{sup −} ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, A., E-mail: akira.ueno@j-parc.jp; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Asano, H.; Oguri, H. [J-PARC Center, Tokai-Mura, Naka-Gun, Ibaraki-Ken 319-1195 (Japan)

    2016-02-15

    The Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven H{sup −} ion source has been successfully operated for about one year. By the world’s brightest level beam, the J-PARC design beam power of 1 MW was successfully demonstrated. In order to minimize the transverse emittances, the rod-filter-field (RFF) was optimized by changing the triple-gap-lengths of each of pairing five piece rod-filter-magnets. The larger emittance degradation seems to be caused by impurity-gases than the RFF. The smaller beam-hole-diameter of the extraction electrode caused the more than expected improvements on not only the emittances but also the peak beam intensity.

  11. Growth of microscopic cones on titanium cathodes of sputter-ion pumps driven by sorption of large argon quantities

    Energy Technology Data Exchange (ETDEWEB)

    Porcelli, Tommaso, E-mail: tommaso-porcelli@saes-group.com [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria, 16, 20133 Milano, Italy and SAES Getters S.p.A., viale Italia, 77, 20020 Lainate, Milan (Italy); Siviero, Fabrizio; Bongiorno, Gero A. [SAES Getters S.p.A., viale Italia, 77, 20020 Lainate, Milan (Italy); Michelato, Paolo [INFN-LASA, via fratelli Cervi, 201, 20090 Segrate, Milan (Italy); Pagani, Carlo [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria, 16, 20133 Milano, Italy and INFN-LASA, via fratelli Cervi, 201, 20090 Segrate, Milan (Italy)

    2015-09-15

    Microscopic cones have been observed on titanium cathodes of sputter-ion pumps (SIPs) after pump operation. The cones were studied by means of scanning electron microscopy and energy dispersive x-ray analysis. Size and morphology of these cones are clearly correlated with the nature and the relative amount of each gas species pumped by each SIP during its working life. In particular, their growth was found to be fed by sputtering mechanisms, mostly during Ar pumping, and to be driven by the electromagnetic field applied to the Penning cells of each SIP. Experimental findings suggest that the formation and extent of such conic structures on cathode surfaces might play a leading role in the onset of phenomena typically related to the functioning of SIPs, e.g., the so-called argon instability.

  12. Relativistic electron's butterfly pitch angle distribution modulated by localized background magnetic field perturbation driven by hot ring current ions

    Science.gov (United States)

    Xiong, Ying; Chen, Lunjin; Xie, Lun; Fu, Suiyan; Xia, Zhiyang; Pu, Zuyin

    2017-05-01

    Dayside modulated relativistic electron's butterfly pitch angle distributions (PADs) from ˜200 keV to 2.6 MeV were observed by Van Allen Probe B at L = 5.3 on 15 November 2013. They were associated with localized magnetic dip driven by hot ring current ion (60-100 keV proton and 60-200 keV helium and oxygen) injections. We reproduce the electron's butterfly PADs at satellite's location using test particle simulation. The simulation results illustrate that a negative radial flux gradient contributes primarily to the formation of the modulated electron's butterfly PADs through inward transport due to the inductive electric field, while deceleration due to the inductive electric field and pitch angle change also makes in part contribution. We suggest that localized magnetic field perturbation, which is a frequent phenomenon in the magnetosphere during magnetic disturbances, is of great importance for creating electron's butterfly PADs in the Earth's radiation belts.

  13. Investigation of heavy ions diffusion under the influence of current-driven mechanism and compositional waves in plasma

    CERN Document Server

    Urpin, Vadim

    2016-01-01

    We consider diffusion caused by a combined influence of the Hall effect and electric currents, and argue that such diffusion forms chemical inhomogeneities in plasma. The considered mechanism can be responsible for the formation of element spots in laboratory and astrophysical plasmas. Such current-driven diffusion can be accompanied by the propagation of a particular type of waves which have not been considered earlier. In these waves, the impurity number density oscillare alone and their frequency is determined by the electric currents and sort of impurity ions. These compositional waves exist if the magnetic pressure in plasma is much greater than the gas pressure. Such waves lead to local variations of chemical composition and, hence, can manifest themselves by variations of the emission in spectral lines.

  14. Progress toward a practical laser driven ion source using variable thickness liquid crystal targets

    Science.gov (United States)

    Poole, Patrick; Cochran, Ginevra; Zeil, Karl; Metzkes, Josephine; Obst, Lieselotte; Kluge, Thomas; Schlenvoigt, Hans-Peter; Prencipe, Irene; Cowan, Tom; Schramm, Uli; Schumacher, Douglass

    2016-10-01

    Ion acceleration from ultra-intense laser interaction has been long investigated in pursuit of requisite energies and spectral distributions for applications like proton cancer therapy. However, the details of ion acceleration mechanisms and their laser intensity scaling are not fully understood, especially the complete role of pulse contrast and target thickness. Additionally, target delivery and alignment at appropriate rates for study and subsequent treatment pose significant challenges. We present results from a campaign on the Draco laser using liquid crystal targets that have on-demand, in-situ thickness tunability over more than three orders of magnitude, enabling rapid data collection due to Education and Research (BMBF, 03Z1O511).

  15. Collisionless shocks driven by 800 nm laser pulses generate high-energy carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.; Shen, B. F., E-mail: bfshen@mail.shcnc.ac.cn; Wang, W. P.; Xu, Y.; Liu, Y. Q.; Liang, X. Y.; Leng, Y. X.; Li, R. X., E-mail: ruxinli@mail.shcnc.ac.cn; Xu, Z. Z. [State Key Laboratory of High Filed Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Yan, X. Q.; Chen, J. E. [State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China)

    2015-01-15

    We present experimental studies on ion acceleration from diamond-like carbon (DLC) foils irradiated by 800 nm, linearly polarized laser pulses with peak intensity of 1.7 × 10{sup 19 }W/cm{sup 2} to 3.5 × 10{sup 19 }W/cm{sup 2} at oblique incidence. Diamond-like carbon foils are heated by the prepulse of a high-contrast laser pulse and expand to form plasmas of near-critical density caused by thermal effect before the arrival of the main pulse. It is demonstrated that carbon ions are accelerated by a collisionless shock wave in slightly overdense plasma excited by forward-moving hot electrons generated by the main pulse.

  16. Modeling and Simulation of Piezoelectrically Driven Self-Charging Lithium Ion Batteries.

    Science.gov (United States)

    Wang, Zhiguo

    2017-05-10

    Self-charging lithium ion batteries (SCLIBs) that hybridize mechanical energy harvesting and storage processes into one process can be fabricated using a piezoelectric polyvinylidene fluoride (PVDF) film as a separator in lithium ion batteries. In this paper, the deintercalation reaction at LiCoO2 and intercalation reaction at graphite were studied under an internal piezoelectric field using density functional theory. It was found that the internal piezoelectric field applied on the anode can increase intercalation energies and diffusion behavior, at the same time, and the internal piezoelectric field facilitates the deintercalation reaction at the cathode. The simulation results revealed the self-charging mechanism of SCLIBs, in which the piezoelectric potential can assist the deintercalation and intercalation proccesses at the cathode and anode upon self-charging, which may be responsible for the experimentally observed efficiency of SCLIBs.

  17. Classification of Jet Fuels by Fuzzy Rule-Building Expert Systems Applied to Three-Way Data by Fast Gas Chromatography-Fast Scanning Quadrupole Ion Trap Mass Spectrometry

    Science.gov (United States)

    2011-01-01

    car - rier gas speed, and a higher head pressure, etc., fast GC separation can be realized. Compared with conventional GC, fast GC offers the...themost common, sensitive, and informativedetectors for GC, MS has promise for the composition-property correlation studyof jet fuels. Time-of-flight ( ToF ... ToF -MS [42]. However, they have the disadvantage of relatively higher costs to purchase and maintain compared to ion trap mass spectrometers. Most

  18. Laser-Driven Ion Acceleration from Plasma Micro-Channel Targets

    Science.gov (United States)

    Zou, D. B.; Pukhov, A.; Yi, L. Q.; Zhou, H. B.; Yu, T. P.; Yin, Y.; Shao, F. Q.

    2017-02-01

    Efficient energy boost of the laser-accelerated ions is critical for their applications in biomedical and hadron research. Achiev-able energies continue to rise, with currently highest energies, allowing access to medical therapy energy windows. Here, a new regime of simultaneous acceleration of ~100 MeV protons and multi-100 MeV carbon-ions from plasma micro-channel targets is proposed by using a ~1020 W/cm2 modest intensity laser pulse. It is found that two trains of overdense electron bunches are dragged out from the micro-channel and effectively accelerated by the longitudinal electric-field excited in the plasma channel. With the optimized channel size, these “superponderomotive” energetic electrons can be focused on the front surface of the attached plastic substrate. The much intense sheath electric-field is formed on the rear side, leading to up to ~10-fold ionic energy increase compared to the simple planar geometry. The analytical prediction of the optimal channel size and ion maximum energies is derived, which shows good agreement with the particle-in-cell simulations.

  19. Numerical simulations of generation of high-energy ion beams driven by a petawatt femtosecond laser

    Directory of Open Access Journals (Sweden)

    Domański Jarosław

    2015-06-01

    Full Text Available This contribution presents results of a Particle-in-Cell simulation of ion beam acceleration via the interaction of a petawatt 25 fs laser pulse of high intensity (up to ~1021 W/cm2 with thin hydrocarbon (CH and erbium hydride (ErH3 targets of equal areal mass density (of 0.6 g/m2. A special attention is paid to the effect that the laser pulse polarization and the material composition of the target have on the maximum ion energies and the number of high energy (>10 MeV protons. It is shown that both the mean and the maximum ion energies are higher for the linear polarization than for the circular one. A comparison of the maximum proton energies and the total number of protons generated from the CH and ErH3 targets using a linearly polarized beam is presented. For the ErH3 targets the maximum proton energies are higher and they reach 50 MeV for the laser pulse intensity of 1021 W/cm2. The number of protons with energies higher than 10 MeV is an order of magnitude higher for the ErH3 targets than that for the CH targets.

  20. Fast carbohydrate analysis via liquid chromatography coupled with ultra violet and electrospray ionization ion trap detection in 96-well format.

    Science.gov (United States)

    Rühmann, Broder; Schmid, Jochen; Sieber, Volker

    2014-07-11

    A fast carbohydrate screening platform processible in 96-well format is described. The method is suitable for the determination of various carbohydrates out of complex mixtures as obtained by acidic hydrolysis of carbohydrates polymers. The chromatographic conditions for an efficient separation (12min) and the derivatization process with 1-phenyl-3-methyl-5-pyrazolone (PMP) were optimized for high resolution separation and simultaneous determination of deoxy-, amino-, anhydro-sugars as well as hexoses, pentoses, dimers, uronic acids and degradation products like furfural and hydroxymethylfurfural (HMF). The potential to quantify with UV- and MS-detector in the same range has been demonstrated for 20 different compounds. Finally, the matrix effects of the hydrolysis were positively evaluated. The micro scale hydrolysis and PMP-derivatization without any extraction or drying steps, both in 96-well format, result in a fast and intuitive sample preparation. In combination with a fast liquid chromatography coupled to UV and electrospray ionization ion trap detection (LC-UV-ESI-MS/MS) for the qualification and quantification of various sugars, dimers and degradation products, this method shows great performance in carbohydrate analysis.

  1. Simulations of fast ion wall loads in ASDEX Upgrade in the presence of magnetic perturbations due to ELM mitigation coils

    CERN Document Server

    Asunta, Otto; Kurki-Suonio, Taina; Koskela, Tuomas; Sipilä, Seppo; Snicker, Antti; Garcia-Muñoz, Manuel

    2015-01-01

    The effect of ASDEX Upgrade (AUG) ELM mitigation coils on fast ion wall loads was studied with the fast particle following Monte Carlo code ASCOT. Neutral beam injected (NBI) particles were simulated in two AUG discharges both in the presence and in the absence of the magnetic field perturbation induced by the eight newly installed in-vessel coils. In one of the discharges (#26476) beams were applied individually, making it a useful basis for investigating the effect of the coils on different beams. However, no ELM mitigation was observed in #26476, probably due to the low plasma density. Therefore, another discharge (#26895) demonstrating clear ELM mitigation was also studied. The magnetic perturbation due to the in-vessel coils has a significant effect on the fast particle confinement, but only when total magnetic field, $B_{tot}$, is low. When $B_{tot}$ was high, the perturbation did not increase the losses, but merely resulted in redistribution of the wall power loads. Hence, it seems to be possible to ac...

  2. The response of a fast phosphor screen scintillator (ZnO:Ga) to low energy ions (0-60 keV)

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Rey, D. [Centro de Micro-Analisis de Materiales, Universidad Autonoma de Madrid, C/ Faraday 3, Campus de Cantoblanco, E-28049 Madrid (Spain); Zurro, B.; Baciero, A.; Navarro, M. [Laboratorio Nacional de Fusion, Asociacion Euratom-CIEMAT, Av. Complutense 22, E-28040 Madrid (Spain); Rodriguez-Barquero, L. [Laboratorio de Metrologia de Radiaciones lonizantes, CIEMAT, Av. Complutense 22, E-28040 Madrid (Spain)

    2010-10-15

    ZnO:Ga is a promising, high time resolution candidate for use as a fast-ion-loss detector in TJ-II. We compare its ionoluminescence with that of the standard fast-ion-loss detector material, SrGa{sub 2}S{sub 4}:Eu (also known as TG-Green), when irradiated by H{sup +} ions with a range of energies E{<=}60 keV using a dedicated laboratory setup. It is found that ZnO:Ga is a reasonably good candidate for detecting low energy (E<60 keV) ions as it has excellent time resolution; however, its sensitivity is about 100 times lower than TG-Green, potentially limiting it to applications with high energy ion loss signals.

  3. Deuterium retention after deuterium plasma implantation in tungsten pre-damaged by fast C+ ions

    Science.gov (United States)

    Efimov, V. S.; Gasparyan, Yu M.; Pisarev, A. A.; Khripunov, B. I.; Koidan, V. S.; Ryazanov, A. I.; Semenov, E. V.

    2016-09-01

    Thermal desorption of deuterium from W was investigated. Virgin samples and samples damaged by 10 MeV C 3+ ions were implanted from plasma in the LENTA facility at 370 K and 773 K. In comparison with the undamaged sample, deuterium retention in the damaged sample slightly increased in the case of deuterium implantation at RT, but decreased in the case of deuterium implantation at 773 K. At 773 K, deuterium was concluded to diffuse far behind the D ion range in the virgin sample, while C implantation region was concluded to be a barrier for D diffusion in the damaged sample.

  4. Characterization of a compact filament-driven multicusp ion source for low energy time-of-flight Rutherford backscattering spectrometry application

    Science.gov (United States)

    Dangtip, S.; Junphong, P.; Ano, V.; Lekprasert, B.; Suwannakachorn, D.; Thongnopparat, N.; Vilaithong, T.

    2004-05-01

    Because of the limited pulse height energy resolution of a detector, conventional Rutherford backscattering spectrometry (RBS) requires an energy of the incident α particle to be in the MeV region. At Chiang Mai University we have researched the possibility of utilizing a 280 keV nanosecond pulse of helium ions for RBS applications. We have chosen a compact filament-driven multicusp ion source of 2.6 cm in diameter and 8 cm in length being investigated for the time-of-flight RBS applications. In this article, we present the general ion source performance using helium, nitrogen, and argon for generating the discharge plasma. The general ion source characteristics have been measured and analyzed. The measurements also include the extractable ion current and the ion beam emittance. We have performed beam extraction calculations with a computer simulation code KOBRA. Results of the measurements and calculations will be presented and discussed.

  5. Germanium as a Sodium Ion Battery Material: In Situ TEM Reveals Fast Sodiation Kinetics with High Capacity

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaotang; Adkins, Emily R.; He, Yang; Zhong, Li; Luo, Langli; Mao, Scott X.; Wang, Chong M.; Korgel, Brian A.

    2016-01-29

    Amorphous germanium (a-Ge) nanowires have great potential for application as anodes in Na-ion batteries. However, the Na-Ge reaction is much less studied and understood compared with other metal alloy anodes. Here, in situ transmission electron microscopy (TEM) is used to study the sodiation/desodiation behavior of a-Ge nanowires. Unexpectedly, our experiments revealed that a-Ge nanowires can be charged at a very fast rate and the final sodiation product, with over 300% volume expansion, is close to Na3Ge instead of NaGe which was considered as the ultimate sodiation state that Ge could achieve. Porous structure was observed in desodiation and, in contrast to delithiation, Na extraction is more likely to create pores in the nanowires due to the much larger radius of the Na ion. This porous structure has demonstrated excellent robustness upon cycling: it could recover flawlessly from the giant pores that were created during experimentation. These results show that the potential of a-Ge for Na-ion battery applications may have been previously underestimated.

  6. Nanoconfined LiBH4 as a Fast Lithium Ion Conductor

    NARCIS (Netherlands)

    Blanchard, Didier; Nale, Angeloclaudio|info:eu-repo/dai/nl/339461845; Sveinbjoernsson, Dadi; Eggenhuisen, Tamara M.|info:eu-repo/dai/nl/313959498; Verkuijlen, Margriet H. W.; Suwarno, Suwarno; Vegge, Tejs; Kentgens, Arno P. M.; de Jongh, Petra E.|info:eu-repo/dai/nl/186125372

    2015-01-01

    Designing new functional materials is crucial for the development of efficient energy storage and conversion devices such as all solid-state batteries. LiBH4 is a promising solid electrolyte for Li-ion batteries. It displays high lithium mobility, although only above 110 degrees C at which a transit

  7. Nanoconfined LiBH4 as a Fast Lithium Ion Conductor

    NARCIS (Netherlands)

    Blanchard, Didier; Nale, Angeloclaudio; Sveinbjoernsson, Dadi; Eggenhuisen, Tamara M.; Verkuijlen, Margriet H. W.; Suwarno, Suwarno; Vegge, Tejs; Kentgens, Arno P. M.; de Jongh, Petra E.

    2015-01-01

    Designing new functional materials is crucial for the development of efficient energy storage and conversion devices such as all solid-state batteries. LiBH4 is a promising solid electrolyte for Li-ion batteries. It displays high lithium mobility, although only above 110 degrees C at which a transit

  8. A New Family of Ce6MoO15 as Fast Oxide Ion Conductor

    Institute of Scientific and Technical Information of China (English)

    Feng Jing; Meng Jian; Bo Qibing; Che Ping; Wang Jingping; Liu Jianfen; Lu Minfeng; Zhang Deping; Fang Daqing; Cao Xueqiang

    2004-01-01

    A novel solid solution Ce6MoO15 was achieved. Their structure and oxide ionic conductivity were studied.Based on Ce6MoO15, rare earth element substitution on cerium site shows that all resulting oxides enhance the conductivity further, and have high oxide-ion conductivity, which may be a kind of promising material for SOFCs.

  9. Vacancies driven magnetic ordering in ZnO nanoparticles due to low concentrated Co ions

    Science.gov (United States)

    Verma, Kuldeep Chand; Bhatia, Ravi; Kumar, Sanjeev; Kotnala, R. K.

    2016-07-01

    The lattice defects due to oxygen vacancies in ZnO nanoparticles with low doping of Co ions are investigated. The low concentrated Co ions in ZnO are responsible to the free charge carriers and oxygen vacancies to induce long-range ferromagnetic ordering. We have synthesized Zn1-x Co x O [x = 0.002, 0.004, 0.006 and 0.008] nanoparticles by a sol-gel process. X-ray fluorescence analysis detects the chemical composition of Zn, Co and O atoms. Rietveld refinement of x-ray diffraction pattern could confirm the wurtzite ZnO structure and the lattice constants with Co doping. The nanoparticles dimensions as well lattice spacing of ZnO are enhanced with Co substitution. Fourier transform infrared vibrational modes involve some organic groups to induce lattice defects and the ionic coordination among Zn, Co and O atoms. The room temperature Raman active mode E2 indicates frequency shifting with Co to induce stress in the wurtzite lattice. Photoluminescence spectra have a strong near-band-edge emission due to band gap energy and defects related to oxygen vacancies. X-ray photoelectron spectra confirm that the low dopant Co ions in ZnO lattice occupied Zn atoms by introducing oxygen vacancies and the valance states Zn2+, Co2,3+. The zero-field and field cooling magnetic measurement at 500 Oe in Co:ZnO samples indicate long-range ferromagnetism that is enhanced at 10 K due to antiferromagnetic-ferromagnetic ordering. The lattice defects/vacancies due to oxygen act as the medium of magnetic interactions which is explained by the bound magnetic polaron model.

  10. Recent development on RF-driven multicusp H{sup {minus}} ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Leung, K.N.; De Vries, G.J.; Kunkel, W.B.; Perkins, L.T.; Pickard, D.S.; Saadatmand, K.; Wengrow, A.B.; Williams, M.D.

    1996-06-01

    The radio-frequency (rf) driven multicusp source was originally developed for use in the Superconducting Super Collider injector. The source routinely provided 35 keV, 30 mA of beam at 0.1% duty factor. By using a new cesium dispensing system, beam current in excess of 100 mA and e/H{sup -} {approx}1 have been observed. For pulse mode operation, the rf discharge can be started by means of a xenon flash lamp. Extracted electrons in the beam can be efficiently removed by employing a permanent magnet insert structure. Chopping of the H{sup - } beam can be accomplished by applying a pulsed positive voltage on the plasma electrode.

  11. Structure and dynamics of the fast lithium ion conductor "Li7La3Zr2O12".

    Science.gov (United States)

    Buschmann, Henrik; Dölle, Janis; Berendts, Stefan; Kuhn, Alexander; Bottke, Patrick; Wilkening, Martin; Heitjans, Paul; Senyshyn, Anatoliy; Ehrenberg, Helmut; Lotnyk, Andriy; Duppel, Viola; Kienle, Lorenz; Janek, Jürgen

    2011-11-21

    The solid lithium-ion electrolyte "Li(7)La(3)Zr(2)O(12)" (LLZO) with a garnet-type structure has been prepared in the cubic and tetragonal modification following conventional ceramic syntheses routes. Without aluminium doping tetragonal LLZO was obtained, which shows a two orders of magnitude lower room temperature conductivity than the cubic modification. Small concentrations of Al in the order of 1 wt% were sufficient to stabilize the cubic phase, which is known as a fast lithium-ion conductor. The structure and ion dynamics of Al-doped cubic LLZO were studied by impedance spectroscopy, dc conductivity measurements, (6)Li and (7)Li NMR, XRD, neutron powder diffraction, and TEM precession electron diffraction. From the results we conclude that aluminium is incorporated in the garnet lattice on the tetrahedral 24d Li site, thus stabilizing the cubic LLZO modification. Simulations based on diffraction data show that even at the low temperature of 4 K the Li ions are blurred over various crystallographic sites. This strong Li ion disorder in cubic Al-stabilized LLZO contributes to the high conductivity observed. The Li jump rates and the activation energy probed by NMR are in very good agreement with the transport parameters obtained from electrical conductivity measurements. The activation energy E(a) characterizing long-range ion transport in the Al-stabilized cubic LLZO amounts to 0.34 eV. Total electric conductivities determined by ac impedance and a four point dc technique also agree very well and range from 1 × 10(-4) Scm(-1) to 4 × 10(-4) Scm(-1) depending on the Al content of the samples. The room temperature conductivity of Al-free tetragonal LLZO is about two orders of magnitude lower (2 × 10(-6) Scm(-1), E(a) = 0.49 eV activation energy). The electronic partial conductivity of cubic LLZO was measured using the Hebb-Wagner polarization technique. The electronic transference number t(e-) is of the order of 10(-7). Thus, cubic LLZO is an almost exclusive

  12. Isolation of Ion-Driven Conformations in Diphenylacetylene Molecular Switches Using Cryogenic Infrared Spectroscopy

    Science.gov (United States)

    Wolk, Arron B.; Garand, Etienne; Jones, Ian M.; Kamrath, Michael Z.; Hamilton, Rew; Johnson, Mark A.

    2012-06-01

    We report the infrared predissociation spectra of a family of ionic diphenylacetylene molecular switch complexes. The electrosprayed complexes were trapped and cooled in a cryogenic (10K) quadrupole ion trap and tagged with molecular deuterium. The infrared spectra of the vibrationally cold species reveal sharp transitions over a wide energy range (800 - 3800 cm-1), facilitating comparison to harmonic spectra. The evolution of the band pattern upon derivatization of the complexes exposes the signatures of the amide, urea, and carbonyl functionalities, enabling unambiguous identification of the non-covalent interactions that control the secondary structure of the molecule. Complexation with the tetramethylammonium cation reveals a conformation analogous to that of the neutral molecule, while halide ion attachment induces a conformational change similar to that observed earlier in solution. In several cases, both the donor and acceptor groups involved in the multidentate H-bonds are observed, providing a microscopic mechanical picture of the interactions at play. I. Jones, and A. Hamilton, Angew. Chem. Intl. Edit. 50, 4597 (2011).

  13. Ion-Mediated Polymerase Chain Reactions Performed with an Electronically Driven Microfluidic Device.

    Science.gov (United States)

    Zhang, Yi; Li, Qian; Guo, Linjie; Huang, Qing; Shi, Jiye; Yang, Yang; Liu, Dongsheng; Fan, Chunhai

    2016-09-26

    The polymerase chain reaction (PCR) is a powerful method for exponentially amplifying very low amounts of target DNA from genetic, clinical, and forensic samples. However, the heating and cooling steps in PCR largely hamper the miniaturization of thermocyclers for on-site detection of pathogens and point-of-care tests. Herein, we devise an ion-mediated PCR (IM-PCR) strategy by exploiting ion-induced DNA denaturation/renaturation cycles. DNA duplexes are effectively denatured in alkaline solutions; whereas, the denatured single-stranded DNA strands readily reform duplexes at neutral pH. By using an integrated microchip that can programmably control the solution pH simply switching the potential in a range of several hundred millivolts, we can trigger IM-PCR at a constant temperature. Analogously to thermal cycling, 30 cycles of pH-induced denaturation/renaturation were used to amplify protein DNA fragments as confirmed by DNA sequencing. We anticipate that this portable, low-cost, and scalable IM-PCR holds great promise for widespread biological, clinical, and environmental applications.

  14. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    Science.gov (United States)

    Skalyga, V.; Izotov, I.; Golubev, S.; Razin, S.; Sidorov, A.; Maslennikova, A.; Volovecky, A.; Kalvas, T.; Koivisto, H.; Tarvainen, O.

    2014-12-01

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D-D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm2 is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·1010 cm-2/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  15. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V., E-mail: skalyga.vadim@gmail.com [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Izotov, I.; Golubev, S.; Razin, S. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Sidorov, A. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Maslennikova, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State Medical Academy, 10/1 Minina Sq., 603005 Nizhny Novgorod (Russian Federation); Volovecky, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Kalvas, T.; Koivisto, H.; Tarvainen, O. [University of Jyvaskyla, Department of Physics, PO Box 35 (YFL), 40500 Jyväskylä (Finland)

    2014-12-21

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D–D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm{sup 2} is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·10{sup 10} cm{sup −2}/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  16. Conceptual study of a compact accelerator-driven neutron source for radioisotope production, boron neutron capture therapy and fast neutron therapy

    CERN Document Server

    Angelone, M; Rollet, S

    2002-01-01

    The feasibility of a compact accelerator-driven device for the generation of neutron spectra suitable for isotope production by neutron capture, boron neutron capture therapy and fast neutron therapy, is analyzed by Monte Carlo simulations. The device is essentially an extension of the activator proposed by Rubbia left bracket CERN/LHC/97-04(EET) right bracket , in which fast neutrons are diffused and moderated within a properly sized lead block. It is shown that by suitable design of the lead block, as well as of additional elements of moderating and shielding materials, one can generate and exploit neutron fluxes with the spectral features required for the above applications. The linear dimensions of the diffusing-moderating device can be limited to about 1 m. A full-scale device for all the above applications would require a fast neutron source of about 10**1**4 s**-**1, which could be produced by a 1 mA, 30 MeV proton beam impinging on a Be target. The concept could be tested at the Frascati Neutron Gener...

  17. Self-organized Ce(1-x)Gd(x)O(2-y) nanowire networks with very fast coarsening driven by attractive elastic interactions.

    Science.gov (United States)

    Gibert, Marta; Abellán, Patricia; Benedetti, Alessandro; Puig, Teresa; Sandiumenge, Felip; García, Alberto; Obradors, Xavier

    2010-12-06

    Assembling arrays of ordered nanowires is a key objective for many of their potential applications. However, a lack of understanding and control of the nanowires' growth mechanisms limits their thorough development. In this work, an appealing new path towards self-organized epitaxial nanowire networks produced by high-throughput solution methods is reported. Two requisites are identified to generate the nanowires: a thermodynamic driving force for an unrestricted elongated equilibrium island shape, and a very fast effective coarsening rate. These requirements are met in anisotropically strained Ce(1-x)Gd(x)O(2-y) nanowires with the (011) orientation grown on the (001) surface of LaAlO(3) substrates. Nanowires with aspect ratios above ≈100 oriented along two mutually orthogonal axes are obtained leading to labyrinthine networks. A very fast effective nanowire growth rate (≈60 nm min(-1)) for ex-situ thermally annealed nanostructures derives from simultaneous kinetic processes occurring in a branched network. Ostwald ripening and anisotropic dynamic coalescence, both promoted by strain-driven attractive nanowire interaction, and rapid recrystallization, enabled by fast atomic diffusion associated with a high concentration of oxygen vacancies, contribute to such an effective growth rate. This bottom-up approach to self-organized nanowire growth has a wide potential for many materials and functionalities.

  18. A fast GPU-based approach to branchless distance-driven projection and back-projection in cone beam CT

    Science.gov (United States)

    Schlifske, Daniel; Medeiros, Henry

    2016-03-01

    Modern CT image reconstruction algorithms rely on projection and back-projection operations to refine an image estimate in iterative image reconstruction. A widely-used state-of-the-art technique is distance-driven projection and back-projection. While the distance-driven technique yields superior image quality in iterative algorithms, it is a computationally demanding process. This has a detrimental effect on the relevance of the algorithms in clinical settings. A few methods have been proposed for enhancing the distance-driven technique in order to take advantage of modern computer hardware. This paper explores a two-dimensional extension of the branchless method proposed by Samit Basu and Bruno De Man. The extension of the branchless method is named "pre-integration" because it achieves a significant performance boost by integrating the data before the projection and back-projection operations. It was written with Nvidia's CUDA platform and carefully designed for massively parallel GPUs. The performance and the image quality of the pre-integration method were analyzed. Both projection and back-projection are significantly faster with preintegration. The image quality was analyzed using cone beam image reconstruction algorithms within Jeffrey Fessler's Image Reconstruction Toolbox. Images produced from regularized, iterative image reconstruction algorithms using the pre-integration method show no significant impact to image quality.

  19. Full solar spectrum light driven thermocatalysis with extremely high efficiency on nanostructured Ce ion substituted OMS-2 catalyst for VOCs purification

    Science.gov (United States)

    Hou, Jingtao; Li, Yuanzhi; Mao, Mingyang; Yue, Yuanzheng; Greaves, G. Neville; Zhao, Xiujian

    2015-01-01

    The nanostructured Ce ion substituted cryptomelane-type octahedral molecular sieve (OMS-2) catalyst exhibits strong absorption in the entire solar spectrum region. The Ce ion substituted OMS-2 catalyst can efficiently transform the absorbed solar energy to thermal energy, resulting in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants such as benzene, toluene, and acetone. Based on the experimental evidence, we propose a novel mechanism of solar light driven thermocatalysis for the Ce ion substituted OMS-2 catalyst. The reason why the Ce ion substituted OMS-2 catalyst exhibits much higher catalytic activity than pure OMS-2 and CeO2/OMS-2 nano composite under the full solar spectrum irradiation is discussed.The nanostructured Ce ion substituted cryptomelane-type octahedral molecular sieve (OMS-2) catalyst exhibits strong absorption in the entire solar spectrum region. The Ce ion substituted OMS-2 catalyst can efficiently transform the absorbed solar energy to thermal energy, resulting in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants

  20. Greater hydrogen ion-induced depression of tension and velocity in skinned single fibres of rat fast than slow muscles.

    Science.gov (United States)

    Metzger, J M; Moss, R L

    1987-12-01

    .v.l., suggesting that apparent positive co-operativity of tension development had increased in soleus and decreased in d.v.l. and s.v.l. fibres. 6. These results (1) demonstrate an increased resistance to H+ ion-mediated contractile dysfunction in slow- compared to fast-twitch single fibres, and (2) support the hypothesis that muscular fatigue resulting from short-term, intense muscular contraction may in part be related to elevated H+ ion concentration.

  1. Protecting ITER walls: fast ion power loads in 3D magnetic field

    Science.gov (United States)

    Kurki-Suonio, T.; Särkimäki, K.; Äkäslompolo, S.; Varje, J.; Liu, Y.; Sipilä, S.; Asunta, O.; Hirvijoki, E.; Snicker, A.; Terävä, J.; Cavinato, M.; Gagliardi, M.; Parail, V.; Saibene, G.

    2017-01-01

    The fusion alpha and beam ion with steady-state power loads in all four main operating scenarios of ITER have been evaluated by the ASCOT code. For this purpose, high-fidelity magnetic backgrounds were reconstructed, taking into account even the internal structure of the ferritic inserts and tritium breeding modules (TBM). The beam ions were found to be almost perfectly confined in all scenarios, and only the so-called hybrid scenario featured alpha loads reaching 0.5 MW due to its more triangular plasma. The TBMs were not found to jeopardize the alpha confinement, nor cause any hot spots. Including plasma response did not bring dramatic changes to the load. The ELM control coils (ECC) were simulated in the baseline scenario and found to seriously deteriorate even the beam confinement. However, the edge perturbation in this case is so large that the sources have to be re-evaluated with plasma profiles that take into account the ECC perturbation.

  2. Fast ion transport in silver halide solid solutions and multiphase systems

    Science.gov (United States)

    Shahi, K.; Wagner, J. B., Jr.

    1980-01-01

    The incorporation of homovalent ions, e.g., I(-) in AgBr, leads to a substantial increase in ionic conductivity sigma. The charge compensation concept does not explain the enhancement. AgBr + 30 mol. % AgI exhibits sigma approximately 7/omega/cm at 380 C, which is approximately 170% larger than that of alpha-AgI, the best known superionic conductor, at its melting point. The purely elastic displacement caused by the foreign ion is suggested to be the origin of such a unique behavior. Furthermore, AgI-AgBr two-phase systems display sigma approximately 10 to the 3rd times higher than predicted by the classical theories.

  3. Design and Construction of a Fast Ion Loss Faraday Cup Array Diagnostic for JET

    Energy Technology Data Exchange (ETDEWEB)

    D.S. Darrow; S. Bauumel; F.E. Cecil; V. Kiptily; R. Ellis; L. Pedrick; A. Werner

    2004-04-26

    A thin foil Faraday cup array is being built to measure the loss of 3.5 MeV alpha particles and MeV ion cyclotron heating (ICH) tail ions on JET. It will consist of nine detectors spread over five different poloidal locations and three radial positions. They will measure the poloidal distribution and radial scrape off of the losses. The detectors will be comprised of four layers of thin (2.5 micron) Ni foil, giving some resolution of the lost particle energy distribution as different ranges of energies will stop in different layers of the detector. One detector will utilize eight thinner (1.0 micron) foils to obtain a better resolved energy distribution. These detectors will accept particles incident up to 45{sup o} from the normal to the foils.

  4. Measurement of time dilation by laser spectroscopy on fast stored Lithium ions

    OpenAIRE

    Reinhardt, S.

    2005-01-01

    In der hier vorgelegten Arbeit werden Frequenzmessungen an schnellen Lithium Ionen als Test der Zeitdilatation vorgestellt. Die Messungen sind am Speicherring TSR am Max-Planck-Institut für Kernphysik durchgeführt worden. Die Übergangsfrequenz eines Zwei-Niveau-Systems im Lithium Ion wird bestimmt, indem eine dopplerfreie Fluoreszens-Sättigungsspektroskopie verwendet wird. Die Spektroskopie wird durch zwei gegenläufige Laser verwirklicht, die kollinear zum Ionenstrahl sind. Zwei Messungen bei...

  5. Synthesis of magnetic graphene nanocomposites decorated with ionic liquids for fast lead ion removal.

    Science.gov (United States)

    Sun, Weiyan; Li, Leilei; Luo, Chuannan; Fan, Lulu

    2016-04-01

    Seeking highly-efficient, low-cost and robust methods to remove metal ions from aqueous solutions is very much in demand. Here, we developed a novel magnetic composite bio-adsorbent, graphene oxide and magnetic chitosan-ionic liquids (GOMCS-ILs), for removing Pb(II) from water. This was the first time to combine ionic liquids and graphene oxide and magnetic chitosan, and apply to the adsorption of metal ions. The addition of ionic liquids can not only improve the dispersivity of the adsorbent, but also increase the adsorption sites. The characteristic result of FTIR, SEM, and XRD showed that GOMCS-ILs were prepared with large surface area and good magnetic responsiveness. The influence of various analytical parameters on the adsorption of Pb(II) such as pH, contact time, and initial ion concentration were studied in detail. The adsorption followed a pseudo second order kinetics. The equilibrium adsorption was well-described by the Langmuir isotherm model and the maximum adsorption capacity was to be 85mgg(-1). Moreover, the GOMCS-ILs could be repeatedly used by simple treatment without obvious structure and performance degradation. These results demonstrated the potential applications of GOMCS-ILs microspheres in efficient removal of Pb(II) from wastewater and deep-purification of polluted water.

  6. Enhanced laser-driven ion acceleration in the relativistic transparency regime

    Energy Technology Data Exchange (ETDEWEB)

    Henig, Andreas; Kiefer, Daniel; Jung, Daniel; Habs, Dietrich [Max-Planck Institut fuer Quantenoptik, Garching (Germany); LMU Muenchen, Department fuer Physik, Garching (Germany); Flippo, Kirk; Gautier, Cord; Letzring, Sam; Johnson, Randy; Shimada, Tom; Yin, Lin; Albright, Brian; Fernandez, Juan [Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Rykovanov, Sergey [Max-Planck Institut fuer Quantenoptik, Garching (Germany); Moscow Physics Engineering Institute, Moscow (Russian Federation); Wu, Hui-Chun [Max-Planck Institut fuer Quantenoptik, Garching (Germany); Markey, Keith; Zepf, Matt [Department of Physics and Astronomy, Queen' s University, Belfast (United Kingdom); Liechtenstein, Vitaly [LMU Muenchen, Department fuer Physik, Garching (Germany); RRC, Kurchatov Institute, Moscow (Russian Federation); Schreiber, Joerg [Max-Planck Institut fuer Quantenoptik, Garching (Germany); LMU Muenchen, Department fuer Physik, Garching (Germany); Plasma Physics Group, Blackett Laboratory, Imperial College, London (United Kingdom); Hegelich, Manuel [LMU Muenchen, Department fuer Physik, Garching (Germany); Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

    2009-07-01

    We report on the acceleration of ion beams from ultra-thin diamond-like carbon (DLC) foils of thickness 50, 30 and 10 nm irradiated by ultra-high contrast laser pulses at intensities of {proportional_to}7 x 10{sup 19} W/cm{sup 2}. An unprecedented maximum energy of 185 MeV (>15 MeV/u) for fully ionized carbon atoms is observed at the optimum thickness of 30 nm. The enhanced acceleration is attributed to self-induced transparency, leading to strong volumetric heating of the classically over-dense electron population in the bulk of the target. Our experimental results are supported by one- and two-dimensional particle-in-cell (PIC) simulations.

  7. On the small divergence of laser-driven ion beams from nanometer thick foils

    Energy Technology Data Exchange (ETDEWEB)

    Bin, J. H.; Ma, W. J.; Allinger, K.; Kiefer, D.; Khrennikov, K.; Karsch, S.; Krausz, F.; Habs, D.; Schreiber, J. [Fakultät für Physik, Ludwig-Maximilians-Universität München, D-85748 Garching (Germany); Max-Planck-Institut für Quantenoptik, D-85748 Garching (Germany); Wang, H. Y. [Max-Planck-Institut für Quantenoptik, D-85748 Garching (Germany); State Key Laboratory of Nuclear Physics and Technology, and Key Lab of High Energy Density Physics Simulation, CAPT, Peking University, Beijing 100871 (China); Reinhardt, S.; Hilz, P.; Tajima, T. [Fakultät für Physik, Ludwig-Maximilians-Universität München, D-85748 Garching (Germany); Yan, X. Q. [State Key Laboratory of Nuclear Physics and Technology, and Key Lab of High Energy Density Physics Simulation, CAPT, Peking University, Beijing 100871 (China)

    2013-07-15

    We report on experimental studies of divergence of proton beams from nanometer thick diamond-like carbon foils irradiated by a linearly polarized intense laser with high contrast. Proton beams with extremely small divergence (half angle) of 2° are observed in addition with a remarkably well-collimated feature over the whole energy range, showing one order of magnitude reduction of the divergence angle in comparison to the results from μm thick targets. Similar features are reproduced in two-dimensional particle-in-cell simulations with parameters representing our experiments, indicating a strong influence from the electron density distribution on the divergence of protons. Our comprehensive experimental study reveals grand opportunities for using nm foils in experiments that require high ion flux and small divergence.

  8. Numerical analysis of atomic density distribution in arc driven negative ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, T., E-mail: t.yamamoto@ppl.appi.keio.ac.jp; Shibata, T.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522 (Japan); Kashiwagi, M.; Hanada, M. [Japan Atomic Energy Agency (JAEA), 801-1 Mukouyama, Naka 311-0193 (Japan); Sawada, K. [Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan)

    2014-02-15

    The purpose of this study is to calculate atomic (H{sup 0}) density distribution in JAEA 10 ampere negative ion source. A collisional radiative model is developed for the calculation of the H{sup 0} density distribution. The non-equilibrium feature of the electron energy distribution function (EEDF), which mainly determines the H{sup 0} production rate, is included by substituting the EEDF calculated from 3D electron transport analysis. In this paper, the H{sup 0} production rate, the ionization rate, and the density distribution in the source chamber are calculated. In the region where high energy electrons exist, the H{sup 0} production and the ionization are enhanced. The calculated H{sup 0} density distribution without the effect of the H{sup 0} transport is relatively small in the upper region. In the next step, the effect should be taken into account to obtain more realistic H{sup 0} distribution.

  9. Focus ion beam-induced mechanical stress switching in an ultra-fast resistive switching device

    Science.gov (United States)

    Yang, Xiang

    2016-06-01

    The Mo/Si3N4:Pt/Pt nanometallic resistive switching devices with ultra-fast write/erase speed (meta-stable state, while LRS (detrapping state) is a stable state. Strong mechanical stress facilitates local bond distortion in dielectric films and thus lowers the energy barrier between HRS and LRS, eventually leading to a barrier-less state transition. A quantitative model based on stress-mediated parallel conduction paths were established to provide a more accurate description of the resistive switching devices.

  10. Fast luminescence in vacuum ultraviolet region in heavy-ion-irradiated α-Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Koshimizu, Masanori, E-mail: koshi@qpc.che.tohoku.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Kimura, Kazuie [RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Fujimoto, Yutaka; Asai, Keisuke [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2015-12-15

    We analyzed the time-resolved luminescence properties of α-Al{sub 2}O{sub 3} under heavy ion irradiations in the vacuum ultraviolet (VUV) wavelength region. A luminescence band at approximately 170 nm, at which a luminescence band was observed under VUV irradiation and was ascribed to self-shrunk excitons. The decay rate increased with the linear energy transfer (LET). The luminescence efficiency of the band increased sharply with the LET for the case of Xe irradiation, whose LET was estimated to be higher than the threshold LET for track formation. The fast decay rate and high luminescence intensity for Xe irradiation was explained according to the enhanced radiative rate caused by close interactions among excited states.

  11. Modeling the response of a fast ion loss detector using orbit tracing techniques in a neutral beam prompt-loss study on the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Pace, D. C.; Heidbrink, W. W.; Muscatello, C. M.; Zhu, Y. B. [University of California-Irvine, Irvine, California 92697 (United States); Fisher, R. K.; Van Zeeland, M. A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Garcia-Munoz, M. [Max-Planck-Institut fuer Plasmaphysik, Garching D-85748 (Germany); Darrow, D. S.; Nazikian, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)

    2010-10-15

    A numerical model describing the expected measurements of neutral beam prompt-losses by a newly commissioned fast ion loss detector (FILD) in DIII-D is presented. This model incorporates the well understood neutral beam deposition profiles from all eight DIII-D beamlines to construct a prompt-loss source distribution. The full range of detectable ion orbit phase space available to the FILD is used to calculate ion trajectories that overlap with neutral beam injection footprints. Weight functions are applied to account for the level of overlap between these detectable orbits and the spatial and velocity (pitch) properties of ionized beam neutrals. An experimental comparison is performed by firing each neutral beam individually in the presence of a ramping plasma current. Fast ion losses determined from the model are in agreement with measured losses.

  12. Benchmarking of computational approaches for fast screening of lithium ion battery electrolyte solvents

    Science.gov (United States)

    Kim, Daejin; Guk, Hyein; Choi, Seung-Hoon; Chung, Dong Hyen

    2017-08-01

    Electrolyte solvents play an important role in lithium-ion batteries. Hence, investigation of the solvent is key to improving battery functionality. We performed benchmark calculations to suggest the best conditions for rapid screening of electrolyte candidates using semi-empirical (SEM) calculations and density functional theory (DFT). A wide selection of Hamiltonians, DFT levels, and basis sets were used for this benchmarking with typical electrolyte solvents. The most efficient condition for reducing computational costs and time is VWN/DNP+ for DFT levels and PM3 for SEM Hamiltonians.

  13. Fast timing with plastic scintillators for in-beam heavy-ion spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hoischen, R., E-mail: robert.hoischen@nuclear.lu.se [Department of Physics, Lund University, SE-22100 Lund (Sweden); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Pietri, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Rudolph, D. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Prokopowicz, W.; Schaffner, H. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Emde, S. [Lehrstuhl fuer Operations Management, Friedrich-Schiller-Universitaet Jena, D-07743 Jena (Germany); Golubev, P. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Wendt, A. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany); Kurz, N.; Wollersheim, H.J.; Gerl, J. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany)

    2011-10-21

    The design, R and D, and testing of a new plastic-scintillator detector for Time-of-Flight measurements with relativistic heavy-ion beams are presented. A design approach using 32 independent precise timing measurements of the same physical event is followed. This is different from the conventional scheme, which aims at two or four high-precision measurements. A circular, 27 cm in diameter, BC-420 plastic-scintillator sheet is read-out by 32 photomultiplier tubes in order to achieve an intrinsic detector resolution on the order of 10 ps root mean square.

  14. Impact of flows on ion temperatures inferred from neutron spectra in asymmetrically driven OMEGA DT implosions

    Science.gov (United States)

    Gatu Johnson, M.; Frenje, J. A.; Seguin, F. H.; Petrasso, R. D.; Aappelbe, B.; Chittenden, J.; Walsh, C.; Knauer, J. P.; Glebov, V. Yu.; Forrest, C.; Marshall, F.; Michel, T.; Stoeckl, C.; Sangster, T. C.; Zylstra, A.

    2016-10-01

    Ion temperatures (Tion) in Inertial Confinement Fusion (ICF) experiments have traditionally been inferred from the broadening of primary neutron spectra. Directional motion (flow) of the fuel at burn, expected to arise due to asymmetries imposed by engineering features (such as stalks, fill tubes, tents, or capsule imperfections) or drive non-uniformity, also impacts broadening and may lead to artificially inflated ``Tion'' values. Flow due to low-mode asymmetries is expected to give rise to line-of-sight variations in measured Tion, as observed in OMEGA cryogenic DT implosions but not in similar experiments at the NIF. In this presentation we report on an OMEGA experiment with intentionally asymmetric drive, designed to test the ability to accurately predict and measure line-of-sight differences in apparent Tion due to low-mode asymmetry-seeded flows. The results provide insight into the complexity of hot-spot dynamics, which is a problem that must be mastered to achieve ICF ignition. This work was supported in part by LLE, the U.S. DoE (NNSA, NLUF) and LLNL.

  15. Alfvenic behavior of alpha particle driven ion cyclotron emission in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Cauffman, S.; Majeski, R. [Princeton Plasma Physics Lab., NJ (United States); McClements, K.G. [UKAEA Government Division, Oxfordshire (United Kingdom). Euratom/UKAEA Fusion Association] [and others

    1995-07-01

    Ion cyclotron emission (ICE) has been observed during D-T discharges in the Tokamak Fusion Test Reactor (TFTR), using rf probes located near the top and bottom of the vacuum vessel. Harmonics of the alpha cyclotron frequency ({Omega}{sub {alpha}}) evaluated at the outer midplane plasma edge are observed at the onset of the beam injection phase of TFTR supershots, and persist for approximately 100-250 ms. These results are in contrast with observations of ICE in JET, in which harmonics of {Omega}{sub {alpha}} evolve with the alpha population in the plasma edge. Such differences are believed to be due to the fact that newly-born fusion alpha particles are super-Alfvenic near the edge of JET plasmas, while they are sub-Alfvenic near the edge of TFTR supershot plasmas. In TFTR discharges with edge densities such that newly-born alpha particles are super-Alfvenic, alpha cyclotron harmonics are observed to persist. These results are in qualitative agreement with numerical calculations of growth rates due to the magnetoacoustic cyclotron instability.

  16. Recovering Paleo-Records from Antarctic Ice-Cores by Coupling a Continuous Melting Device and Fast Ion Chromatography.

    Science.gov (United States)

    Severi, Mirko; Becagli, Silvia; Traversi, Rita; Udisti, Roberto

    2015-11-17

    Recently, the increasing interest in the understanding of global climatic changes and on natural processes related to climate yielded the development and improvement of new analytical methods for the analysis of environmental samples. The determination of trace chemical species is a useful tool in paleoclimatology, and the techniques for the analysis of ice cores have evolved during the past few years from laborious measurements on discrete samples to continuous techniques allowing higher temporal resolution, higher sensitivity and, above all, higher throughput. Two fast ion chromatographic (FIC) methods are presented. The first method was able to measure Cl(-), NO3(-) and SO4(2-) in a melter-based continuous flow system separating the three analytes in just 1 min. The second method (called Ultra-FIC) was able to perform a single chromatographic analysis in just 30 s and the resulting sampling resolution was 1.0 cm with a typical melting rate of 4.0 cm min(-1). Both methods combine the accuracy, precision, and low detection limits of ion chromatography with the enhanced speed and high depth resolution of continuous melting systems. Both methods have been tested and validated with the analysis of several hundred meters of different ice cores. In particular, the Ultra-FIC method was used to reconstruct the high-resolution SO4(2-) profile of the last 10,000 years for the EDML ice core, allowing the counting of the annual layers, which represents a key point in dating these kind of natural archives.

  17. Double differential distribution of electron emission in the ionization of water molecules by fast bare oxygen ions

    Science.gov (United States)

    Bhattacharjee, Shamik; Biswas, Shubhadeep; Bagdia, Chandan; Roychowdhury, Madhusree; Nandi, Saikat; Misra, Deepankar; Monti, J. M.; Tachino, C. A.; Rivarola, R. D.; Champion, C.; Tribedi, Lokesh C.

    2016-03-01

    The doubly differential distributions of low-energy electron emission in the ionization of water molecules under the impact of fast bare oxygen ions with energy of 48 MeV are measured. The measured data are compared with two quantum-mechanical models, i.e. the post and prior versions of the continuum distorted wave-eikonal initial state (CDW-EIS) approximation, and the first-order Born approximation with initial and final wavefunctions verifying correct boundary conditions (CB1). An overall excellent qualitative agreement is found between the data and the CDW-EIS models whereas the CB1 model showed substantial deviation. However, the detailed angular distributions display some discrepancies with both CDW-EIS models. The single differential and total cross-sections exhibit good agreement with the CDW-EIS models. The present detailed data set could also be used as an input for modeling highly charged ion induced radiation damage in living tissues, whose most abundant component is water. Similar measurements are also carried out for a projectile energy of 60 MeV. However, since the double differential cross-section data show similar results the details are not provided here, except for the total ionization cross-sections results.

  18. Properties of the First-order Fermi acceleration in fast magnetic reconnection driven by turbulence in collisional MHD flows

    CERN Document Server

    del Valle, M V; Kowal, G

    2016-01-01

    Fast magnetic reconnection may occur in different astrophysical sources, producing flare-like emission and particle acceleration. Currently, this process is being studied as an efficient mechanism to accelerate particles via a first-order Fermi process. In this work we analyse the acceleration rate and the energy distribution of test particles injected in three-dimensional magnetohydrodynamical (MHD) domains with large-scale current sheets where reconnection is made fast by the presence of turbulence. We study the dependence of the particle acceleration time with the relevant parameters of the embedded turbulence, i.e., the Alfv\\'en speed $V_{\\rm A}$, the injection power $P_{\\rm inj}$ and scale $k_{\\rm inj}$ ($k_{\\rm inj} = 1/l_{\\rm inj}$). We find that the acceleration time follows a power-law dependence with the particle kinetic energy: $t_{acc} \\propto E^{\\alpha}$, with $0.2 < \\alpha < 0.6$ for a vast range of values of $c / V_{\\rm A} \\sim 20 - 1000$. The acceleration time decreases with the Alfv\\'en...

  19. Fast and Large-Scale Anodizing Synthesis of Pine-Cone TiO2 for Solar-Driven Photocatalysis

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2017-08-01

    Full Text Available Anodization has been widely used to synthesize nanostructured TiO2 films with promising photocatalytic performance for solar hydrogen production and pollution removal. However, it usually takes a few hours to obtain the right nanostructures even on a small scale (e.g., 10 mm × 20 mm. In order to attract interest for industrial applications, fast and large-scale fabrication is highly desirable. Herein, we demonstrate a fast and large-scale (e.g., 300 mm × 360 mm synthesis of pine-cone TiO2 nanostructures within two min. The formation mechanism of pine-cone TiO2 is proposed. The pine-cone TiO2 possesses a strong solar absorption, and exhibits high photocatalytic activities in photo-oxidizing organic pollutants in wastewater and producing hydrogen from water under natural sunlight. Thus, this study demonstrates a promising method for fabricating TiO2 films towards practical photocatalytic applications.

  20. Safe and fast-charging Li-ion battery with long shelf life for power applications

    Science.gov (United States)

    Zaghib, K.; Dontigny, M.; Guerfi, A.; Charest, P.; Rodrigues, I.; Mauger, A.; Julien, C. M.

    We report a Li-ion battery that can be charged within few minutes, passes the safety tests, and has a very long shelf life. The active materials are nanoparticles of LiFePO 4 (LFP) and Li 4Ti 5O 12 (LTO) for the positive and negative electrodes, respectively. The LiFePO 4 particles are covered with 2 wt.% carbon to optimize the electrical conductivity, but not the Li 4Ti 5O 12 particles. The electrolyte is the usual carbonate solvent. The binder is a water-soluble elastomer. The "18650" battery prepared under such conditions delivers a capacity of 800 mAh. It retains full capacity after 20,000 cycles performed at charge rate 10C (6 min), discharge rate 5C (12 min), and retains 95% capacity after 30,000 cycles at charge rate 15C (4 mn) and discharge rate 5C both at 100% DOD and 100% SOC.