WorldWideScience

Sample records for two-dimensional thomson scattering

  1. Thomson scattering from laser plasmas

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-01-12

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

  2. Quantum theory of Thomson scattering

    Science.gov (United States)

    Crowley, B. J. B.; Gregori, G.

    2014-12-01

    The general theory of the scattering of electromagnetic radiation in atomic plasmas and metals, in the non-relativistic regime, in which account is taken of the Kramers-Heisenberg polarization terms in the Hamiltonian, is described from a quantum mechanical viewpoint. As well as deriving the general formula for the double differential Thomson scattering cross section in an isotropic finite temperature multi-component system, this work also considers closely related phenomena such as absorption, refraction, Raman scattering, resonant (Rayleigh) scattering and Bragg scattering, and derives many essential relationships between these quantities. In particular, the work introduces the concept of scattering strength and the strength-density field which replaces the normal particle density field in the standard treatment of scattering by a collection of similar particles and it is the decomposition of the strength-density correlation function into more familiar-looking components that leads to the final result. Comparisons are made with previous work, in particular that of Chihara [1].

  3. Alpha particle collective Thomson scattering in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Machuzak, J.S.; Woskov, P.P.; Rhee, D.Y.; Gilmore, J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center; Bretz, N.L.; Park, H.K. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Aamodt, R.E.; Cheung, P.Y.; Russell, D.A. [Lodestar Research Corp., Boulder, CO (United States); Bindslev, H. [JET Joint Undertaking, Abingdon (United Kingdom)

    1993-11-01

    A collective Thomson scattering diagnostic is being implemented on TFTR to measure alpha particle, energetic and thermal ion densities and velocity distributions. A 60 GHz, 0.1-1 kW gyrotron will be used as the transmitter source, and the scattering geometry will be perpendicular to the magnetic field in the extraordinary mode polarization. An enhanced scattered signal is anticipated from fluctuations in the lower hybrid frequency range with this scattering geometry. Millimeter wave collective Thomson scattering diagnostics have the advantage of larger scattering angles to decrease the amount of stray light, and long, high power, modulated pulses to obtain improved signal to noise through synchronous detection techniques.

  4. Thomson-scattering systems on TMX

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, R.K.; Clauser, J.F.; Frank, A.M.; Goerz, D.A.; Lang, D.D.

    1982-01-30

    This report summarizes the criteria and designs that were used for the two TMX Thomson-scattering systems. It describes the optical, mechanical, electronic, and computer analysis features of these installations. A brief discussion of general Thomson-scattering principles and sensitivity limits is given. Also included are some plasma electron temperature and density measurements from TMX that were obtained through the use of these systems.

  5. Thomson Scattering in the Solar Corona

    CERN Document Server

    Inhester, Bernd

    2015-01-01

    The fundaments of the application of Thomson scattering to the analysis of coronagraph images has been laid decades ago. Even though the basic formulation is undebated, a discussion has grown in recent years about the spatial distribution of Thomson scatter sensitivity in space. These notes are an attempt to clarify the understanding about this topic. We reformulate the classical calculations in a more transparent way using modern SI-compatible quantities and extend the scattering calculations to the case of relativistic electrons. Many mathematical and some basic physical ingredients are made explicit in several chapters of the appendix.

  6. Double pulse Thomson scattering system at RTP

    NARCIS (Netherlands)

    Beurskens, M. N. A.; Barth, C. J.; Chu, C.C.; Donne, A. J. H.; Herranz, J. A.; Cardozo, N. J. L.; van der Meiden, H. J.; Pijper, F.J.

    1997-01-01

    In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10-800 mu s, max. 2x12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator fo

  7. Theory of Thomson scattering in inhomogeneous media

    CERN Document Server

    Kozlowski, P M; Gericke, D O; Regan, S P; Gregori, G

    2016-01-01

    Thomson scattering of laser light is one of the most fundamental diagnostics of plasma density, temperature and magnetic fields. It relies on the assumption that the properties in the probed volume are homogeneous and constant during the probing time. On the other hand, laboratory plasmas are seldom uniform and homogeneous on the temporal and spatial dimensions over which data is collected. This is partic- ularly true for laser-produced high-energy-density matter, which often exhibits steep gradients in temperature, density and pressure, on a scale determined by the laser focus. Here, we discuss the modification of the cross section for Thomson scattering in fully-ionized media exhibiting steep spatial inhomogeneities and/or fast temporal fluctuations. We show that the predicted Thomson scattering spectra are greatly altered compared to the uniform case, and may even lead to violations of detailed balance. Therefore, careful interpretation of the spectra is necessary for spatially or temporally inhomogeneous ...

  8. Theory of Thomson scattering in inhomogeneous media

    Science.gov (United States)

    Kozlowski, P. M.; Crowley, B. J. B.; Gericke, D. O.; Regan, S. P.; Gregori, G.

    2016-04-01

    Thomson scattering of laser light is one of the most fundamental diagnostics of plasma density, temperature and magnetic fields. It relies on the assumption that the properties in the probed volume are homogeneous and constant during the probing time. On the other hand, laboratory plasmas are seldom uniform and homogeneous on the temporal and spatial dimensions over which data is collected. This is particularly true for laser-produced high-energy-density matter, which often exhibits steep gradients in temperature, density and pressure, on a scale determined by the laser focus. Here, we discuss the modification of the cross section for Thomson scattering in fully-ionized media exhibiting steep spatial inhomogeneities and/or fast temporal fluctuations. We show that the predicted Thomson scattering spectra are greatly altered compared to the uniform case, and may lead to violations of detailed balance. Therefore, careful interpretation of the spectra is necessary for spatially or temporally inhomogeneous systems.

  9. The Thomson Scattering System at DANTE

    DEFF Research Database (Denmark)

    Gadeberg, M.

    This report describes the construction and operation of the 90 deg Thomson Scattering diagnostic at DANTE. The system is based on a double-pulse ruby laser and a three channel spectrometer. Two single point measurements can be made during each plasma discharge.......This report describes the construction and operation of the 90 deg Thomson Scattering diagnostic at DANTE. The system is based on a double-pulse ruby laser and a three channel spectrometer. Two single point measurements can be made during each plasma discharge....

  10. Pulsed Laser Nonlinear Thomson Scattering for General Scattering Geometries

    Energy Technology Data Exchange (ETDEWEB)

    Geoffrey Krafft; A. Doyuran; James Rosenzweig

    2005-05-01

    In a recent paper it has been shown that single electron Thomson backscatter calculations can be performed including the effects of pulsed high intensity lasers. In this paper we present a more detailed treatment of the problem and present results for more general scattering geometries. In particular, we present new results for 90 degree Thomson scattering. Such geometries have been increasingly studied as X-ray sources of short-pulse radiation. Also, we present a clearer physical basis for these different cases.

  11. Low-frequency scattering from two-dimensional perfect conductors

    DEFF Research Database (Denmark)

    Hansen, Thorkild; Yaghjian, A.D

    1991-01-01

    Exact expressions have been obtained for the leading terms in the low-frequency expansions of the far fields scattered from three different types of two-dimensional perfect conductors: a cylinder with finite cross section, a cylindrical bump on an infinite ground plane, and a cylindrical dent...

  12. Corotational Tomography of Heliospheric Features Using Global Thomson Scattering Data

    Science.gov (United States)

    Jackson, Bernard V.; Hick, P. Paul

    2002-12-01

    The Air Force/NASA Solar Mass Ejection Imager (SMEI) will provide two-dimensional images of the sky in visible light with high (0.1%) photometric precision, and unprecedented sky coverage and cadence. To optimize the information available from these images they must be interpreted in three dimensions. We have developed a Computer Assisted Tomography (CAT) technique that fits a three-dimensional kinematic heliospheric model to remotely-sensed Thomson scattering observations. This technique is designed specifically to determine the corotating background solar wind component from data provided by instruments like SMEI. Here, we present results from this technique applied to the Helios spacecraft photometer observations. The tomography program iterates to a least-squares solution of observed brightnesses using solar rotation, spacecraft motion and solar wind outflow to provide perspective views of each point in space covered by the observations. The corotational tomography described here is essentially the same as used by Jackson et al. (1998) for the analysis of interplanetary scintillation (IPS) observations. While IPS observations are related indirectly to the solar wind density through an assumed (and uncertain) relationship between small-scale density fluctuations and density, Thomson scattering physics is more straightforward, i.e., the observed brightness depends linearly on the solar wind density everywhere in the heliosphere. Consequently, Thomson scattering tomography can use a more direct density-convergence criterion to match observed Helios photometer brightness to brightness calculated from the model density. The general similarities between results based on IPS and Thomson scattering tomography validate both techniques and confirm that both observe the same type of solar wind structures. We show results for Carrington rotation 1653 near solar minimum. We find that longitudinally segmented dense structures corotate with the Sun and emanate from near the

  13. HT-7 Multipoint Nd Laser Thomson Scattering Apparatus

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A compact, low cost, multipoint Thomson scattering diagnostic system for HT-7 superconducting tokamak has been in operation since 1999. Its capability of measuring electron temperatures is in the range of 200 eV to 2 keV at a density of a few times 1012 cm-3, with a spatial resolution of 2.4 cm for 5 spatial points and a temporal resolution of 1 ms~1 s for 8 time points. The main components of the diagnostic system include a 20~25 J Nd:glass laser with 35 ns pulse width (8 pulses per burst), a KDP frequency-doubling unit, spherical mirrors of multipass input optical system, a wide-angle collection objective, a bandpass glass filter for reducing the stray light to zero, a f/2.5 polychromator, a fiberglass collimator, a photomultiplier's box with electronic preamplifier, high gain and high signal/noise ratio, CAMAC data acquisition and so on.The multipass optical system has been successful at increasing the quantity of scattered photons by passing the probing laser beam 10 times through the plasma under investigation. The HT7 Thomson scattering diagnostic has provided successfully the information on two-dimensional electron temperature in the plasma of HT-7 tokamak with LHCD and IBW.

  14. Thomson scattering off a pair (electron-positron) plasma

    Institute of Scientific and Technical Information of China (English)

    Zheng Jian

    2006-01-01

    Thomson scattering off a pair (electron-positron) plasma is theoretically investigated in the collisionless and collisional limits respectively. Our calculations show that the power spectrum of the Thomson scattering offa collisionless pair plasma is just proportional to the velocity distribution function of the particles in the plasma. Collective modes in the plasma do not have any effects on the Thomson scattering spectrum because of the correlation between the negatively- and positively-charged particles. In the collisional limit, the power spectrum of the Thomson scattering presents three spikes: two peaks correspond to two contra-propagating sound waves and one peak corresponds to an entropy wave.

  15. MFTF Thomson scattering: a system study

    Energy Technology Data Exchange (ETDEWEB)

    Frank, A.M.

    1980-09-11

    This report documents the design effort for a Thomson scattering diagnostic system for MFTF. The principal problem is obtaining enough photons, in the presence of a poorly known background, to make satisfactory measurements. No currently available laser will yield enough photons to do this. Design concepts for imaging and detection are discussed. The ability of components to survive in the high-radiation environment of MFTF is identified as an important problem. The transition to MFTF-B makes many of the problems identified here more serious.

  16. Operation of the NSTX Thomson Scattering System

    Energy Technology Data Exchange (ETDEWEB)

    LeBlanc, B.P.; Bell, R.E.; Johnson, D.W.; Hoffman, D.E.; Long, D.C.; and Palladino, R.W.

    2002-09-03

    The NSTX multi-point Thomson scattering system has been in operation for nearly two years and provides routine Te(R,t) and ne(R,t) measurements. The laser beams from two 30-Hz Nd:YAG lasers are imaged by a spherical mirror onto 36 fiber-optics bundles. In the present configuration, the output ends of 20 of these bundles are instrumented with filter polychromators and avalanche photodiode detectors. In this paper, we discuss the laser implementation and the installed collection optics. We follow with examples of raw and analyzed data. We close with some comments about calibration.

  17. Thomson Scattering Process in Laser-Produced Plasmas

    Institute of Scientific and Technical Information of China (English)

    YU Quan-Zhi; JIANG Xiao-Hua; LI Wen-Hong; LIU Shen-Ye; ZHENG Zhi-Jian; ZHANG Jie; LI Yu-Tong; ZHENG Jun; YAN Fei; LU Xin; WANG Zhe-Bin; ZHENG Jian; YU Chang-Xuan

    2005-01-01

    @@ We present the evolutions of the electron temperature and plasma expansion velocity with Thomson scattering experiment. The observed time-resolved ion-acoustic image is reproduced by a numerical code which couples the Thomson scattering theory with the output parameters of the one-dimensional hydrocode MEDUSA.

  18. Thomson scattering of polarized photons in an intense laser beam

    Energy Technology Data Exchange (ETDEWEB)

    Byung Yunn

    2006-02-21

    We present a theoretical analysis of the Thomson scattering of linearly and circularly polarized photons from a pulsed laser by electrons. The analytical expression for the photon distribution functions presented in this paper should be useful to designers of Thomson scattering experiments.

  19. A compact multichannel spectrometer for Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R. [Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2012-10-15

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T{sub e} < 100 eV are achieved by a 2971 l/mm VPH grating and measurements T{sub e} > 100 eV by a 2072 l/mm VPH grating. The spectrometer uses a fast-gated ({approx}2 ns) ICCD camera for detection. A Gen III image intensifier provides {approx}45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  20. A compact multichannel spectrometer for Thomson scattering.

    Science.gov (United States)

    Schoenbeck, N L; Schlossberg, D J; Dowd, A S; Fonck, R J; Winz, G R

    2012-10-01

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T(e) VPH grating and measurements T(e) > 100 eV by a 2072 l∕mm VPH grating. The spectrometer uses a fast-gated (~2 ns) ICCD camera for detection. A Gen III image intensifier provides ~45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  1. Thomson Scattering at FLASH - Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Toleikis, S; Bornath, T; Cao, L; Doppner, T; Dusterer, S; Faustlin, R; Forster, E; Fortmann, C; Glenzer, S H; Gode, S; Gregori, G; Holl, A; Irsig, R; Laarmann, T; Lee, H J; Meiwes-Broer, K H; Przystawik, A; Radcliffe, P; Redmer, R; Reinholz, H; Ropke, G; Thiele, R; Tiggesbaumker, J; Truong, N X; Tschentscher, T; Uschmann, I; Zastrau, U

    2007-11-28

    The basic idea is to implement Thomson scattering with free electron laser (FEL) radiation at near-solid density plasmas as a diagnostic method which allows the determination of plasma temperatures and densities in the warm dense matter (WDM) regime (free electron density of n{sub e} = 10{sup 21}-10{sup 26} cm{sup -3} with temperatures of several eV). The WDM regime [1] at near-solid density (n{sub e} = 10{sup 21}-10{sup 22} cm{sup -3}) is of special interest because, it is where the transition from an ideal plasma to a degenerate, strongly coupled plasma occurs. A systematic understanding of this largely unknown WDM domain is crucial for the modeling and understanding of contemporary plasma experiments, like laser shock-wave or Z-pinch experiments as well as for inertial confinement fusion (ICF) experiments as the plasma evolution follows its path through this domain.

  2. Experimental challenges of Traveling-wave Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Debus, Alexander; Steiniger, Klaus; Siebold, Mathias; Jochmann, Axel; Irman, Arie; Bussmann, Michael; Schramm, Ulrich; Cowan, Thomas; Sauerbrey, Roland [Forschungzentrum Dresden-Rossendorf, Institute for Radiation Physics, 01328 Dresden (Germany)

    2011-07-01

    Traveling-wave Thomson scattering is a novel interaction design that allows circumventing the Rayleigh limit in optical undulators, which is interesting for possible realizations of Thomson scattering sources with photon yields per pulse that are 2-3 orders of magnitudes beyond current designs. Here we present details on how a Traveling-wave setup has to be implemented in experiment. An emphasis is put on the use of varied-line spacing (VLS) gratings for spatio-temporal beam shaping at large interaction angles to achieve optimal overlap. At the FZD we are using the high-power laser system DRACO (250TW) to realize a Thomson source with electrons from the linear accelerator ELBE or laser-plasma accelerated electrons. We present the current status and further progress towards a head-on Thomson source and a Traveling-Wave Thomson scattering source aiming for high photon yields per pulse.

  3. Dense Matter Characterization by X-ray Thomson Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Landen, O L; Glenzer, S H; Edwards, M J; Lee, R W; Collins, G W; Cauble, R C; Hsing, W W; Hammel, B A

    2000-12-29

    We discuss the extension of the powerful technique of Thomson scattering to the x-ray regime for providing an independent measure of plasma parameters for dense plasmas. By spectrally-resolving the scattering, the coherent (Rayleigh) unshifted scattering component can be separated from the incoherent Thomson component, which is both Compton and Doppler shifted. The free electron density and temperature can then be inferred from the spectral shape of the high frequency Thomson scattering component. In addition, as the plasma temperature is decreased, the electron velocity distribution as measured by incoherent Thomson scattering will make a transition from the traditional Gaussian Boltzmann distribution to a density-dependent parabolic Fermi distribution to. We also present a discussion for a proof-of-principle experiment appropriate for a high energy laser facility.

  4. Thomson Scattering Measurements of Plasma Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Holl, A; Redmer, R; Tschentscher, T; Toleikis, S; Forster, E; Cao, L; Glenzer, S H; Neumayer, P

    2006-03-29

    The authors propose to investigate the dynamics of plasmas in the warm dense matter (WDM) regime on ultra-short time scales. Accessible plasma conditions are in the density range of n = 10{sup 20} - 10{sup 23} cm{sup -3} and at moderate temperatures of T = 1 - 20 eV. These plasmas are of importance for laboratory astrophysics, high energy density science and inertial confinement fusion. They are characterized by a coupling parameter of {Lambda} {approx}> 1, where electromagnetic interactions are of the same order as the kinetic energy. The high density of the plasma makes it opaque to radiation in the visible range and, as a consequence, UV up to x-ray radiation can be used to probe such systems. Therefore a wide range in the temperature-density plane of WDM is presently unexplored and only the VUV-FEL opens for the first time the opportunity for its detailed investigation. In equilibrium, the macroscopic state of the plasma is completely characterized by its density and temperature. In pump-probe experiments however, the plasma is initially in a nonequilibrium state and relaxes towards equilibrium within the relaxation time {tau}{sub R}. For t > {tau}{sub R}, the plasma is in an equilibrium state and expands hydrodynamically on a time scale {tau}{sub H}. The proposed experiment measures the time-resolved Thomson scattering signal with the VUV-FEL radiation characterizing the plasma in equilibrium and nonequilibrium states. Both regimes are extremely interesting and will provide new insight into the following phenomena: (1) details of nonequilibrium correlations, (2) relaxation phenomena, (3) hydrodynamic expansion, (4) recombination kinetics. The time-resolved Thomson scattering signal is obtained in a pump-probe experiment by varying the delay between pump and probe. The final stage of the relaxation process (t {approx} {tau}{sub R}) is of special interest since the plasma components (electrons and ion species) can be assumed to be in quasi-equilibrium. This

  5. Thomson scattering upgrade on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Leroux, F., E-mail: fabrice.leroux@cea.f [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Manenc, L.; Moreau, M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2010-07-15

    The Thomson scattering diagnostic supplies the electron temperature and density of Tore Supra plasmas from the spectrum analysis of scattered light of a very short laser pulse. A new spectrometer has been realized to improve the signal to noise ratio. In order to obtain an efficient noise reduction, a real time calculation is necessary. The current analogue integration of the signal is inadequate. A fast digitalization must be used with a sampling rate of 1 GSamples/s, a bandwidth of 150 MHz and a 12 bits dynamic range. In a first step, fast analogue data acquisition boards for 4 channels were added in 2009 to the VME acquisition system in place. A MATACQ (Matrix for acquisition) board was chosen for sampling analogue data up to 2 GSamples/s over 4 channels with a large bandwidth of 300 MHz and a 14 bits dynamic range. This solution offers a low cost acquisition system that is not available in any other commercial board with this dynamic range. The first results will be obtained on calibration period with a light emitted diode before the summer 2009. This article will present the new data acquisition system and the coming first results.

  6. Plasma Jet Interaction with Thomson Scattering Probe Laser

    Science.gov (United States)

    Byvank, Tom; Banasek, Jacob; Potter, William; Kusse, Bruce

    2016-10-01

    Thomson scattering systems can diagnose plasma temperatures and velocities. When probing a plasma jet with the Thomson scattering laser, we observe a laser-plasma interaction that inputs energy into the plasma jet. The absorbed energy causes a bubble of low density ( 5*1017 cm-2) in the jet (unperturbed 1018 cm-2). A pulsed power machine (1 MA peak current, 100 ns rise time) with a radial foil (15 μm thick Al) configuration generates the plasma jet. We compare the effects of using 10 J and 1 J laser energies, for which the 10 J laser is a larger perturbation. We discuss how the interaction affects the Thomson scattering temperature and velocity measurements. Work supported by National Nuclear Security Administration (NNSA) Stewardship Sciences Academic Programs under Department of Energy (DOE) Cooperative Agreement DE-NA0001836 and National Science Foundation (NSF) Grant PHY-1102471.

  7. Thomson scattering from laser induced plasma in air

    Energy Technology Data Exchange (ETDEWEB)

    Dzierzega, K; Mendys, A [Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland); Pellerin, S; Thouin, E [GREMI - site de Bourges, Universite d' Orleans, rue Gaston Berger BP 4043, 18028 Bourges (France); Travaille, G; Bousquet, B; Canioni, L [Centre de Physique Moleculaire Optique et Hertzienne, Universite Bordeaux I, 351 Cours de la Liberation, 33405 Talence CEDEX (France); Pokrzywka, B, E-mail: krzysztof.dzierzega@uj.edu.p [Mt. Suhora Observatory, Pedagogical University of Cracow, ul. Podchorazych 2, 30-084 Krakow (Poland)

    2010-05-01

    The laser induced plasma in air produced by 6 ns, 532 nm Nd:YAG pulses with 25 mJ energy was studied using the Thomson scattering method and plasma imaging techniques. Plasma images and Thomson scattered spectra were registered at delay times ranging from 150 ns to 1 {mu}s after the breakdown pulses. The electron density and temperature, as determined in the core of the plasma plume, were found to decrease from 7.4 x 10{sup 17} cm{sup -3} to about 1.03 x 10{sup 17} cm{sup -3} and from 100 900 K to 22 700 K. The highly elevated electron temperatures are the result of plasma heating by the second, probe pulse in the Thomson scattering experiments.

  8. The LIDAR Thomson Scattering Diagnostic on JET

    DEFF Research Database (Denmark)

    Salzmann, H.; Bundgaard, J.; Gadd, A.

    1988-01-01

    By combining the time‐of‐flight or LIDAR principle with a Thomson backscatter diagnostic, spatial profiles of the electron temperature and density are measured in a magnetically confined fusion plasma. This technique was realized for the first time on the JET tokamak. A ruby laser (3‐J pulse energy...

  9. LIDAR Thomson scattering for advanced tokamaks. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Molvik, A.W.; Lerche, R.A.; Nilson, D.G. [and others

    1996-03-18

    The LIDAR Thomson Scattering for Advanced Tokamaks project made a valuable contribution by combining LLNL expertise from the MFE Program: tokamak design and diagnostics, and the ICF Program and Physics Dept.: short-pulse lasers and fast streak cameras. This multidisciplinary group evaluated issues involved in achieving a factor of 20 higher high spatial resolution (to as small as 2-3 mm) from the present state of the art in LIDAR Thomson scattering, and developed conceptual designs to apply LIDAR Thomson scattering to three tokamaks: Upgraded divertor measurements in the existing DIII-D tokamak; Both core and divertor LIDAR Thomson scattering in the proposed (now cancelled) TPX; and core, edge, and divertor LIDAR Thomson scattering on the presently planned International Tokamak Experimental Reactor, ITER. Other issues were evaluated in addition to the time response required for a few millimeter spatial resolution. These include the optimum wavelength, 100 Hz operation of the laser and detectors, minimizing stray light - always the Achilles heel of Thomson scattering, and time dispersion in optics that could prevent good spatial resolution. Innovative features of our work included: custom short pulsed laser concepts to meet specific requirements, use of a prism spectrometer to maintain a constant optical path length for high temporal and spatial resolution, the concept of a laser focus outside the plasma to ionize gas and form an external fiducial to use in locating the plasma edge as well as to spread the laser energy over a large enough area of the inner wall to avoid laser ablation of wall material, an improved concept for cleaning windows between shots by means of laser ablation, and the identification of a new physics issue - nonlinear effects near a laser focus which could perturb the plasma density and temperature that are to be measured.

  10. A polarization-based Thomson scattering technique for burning plasmas

    CERN Document Server

    Parke, E; Hartog, D J Den

    2013-01-01

    The traditional Thomson scattering diagnostic is based on measurement of the wavelength spectrum of scattered light, where electron temperature measurements are inferred from thermal broadening of the scattered laser light. At sufficiently high temperatures, especially those predicted for ITER and other burning plasmas, relativistic effects cause a change in the polarization state of the scattered photons. The resulting depolarization of the scattered light is temperature dependent and has been proposed elsewhere as a potential alternative to the traditional spectral decomposition technique. Following similar work, we analytically calculate the degree of polarization for incoherent Thomson scattering. For the first time, we obtain exact results valid for the full range of incident laser polarization states and electron temperatures. While previous work focused only on linear polarization, we show that circularly polarized incident light optimizes the degree of depolarization for a wide range of temperatures r...

  11. Warm, Dense Plasma Characterization by X-ray Thomson Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Landen, O L; Glenzer, S H; Cauble, R C; Lee, R W; Edwards, J E; Degroot, J S

    2000-07-18

    We describe how the powerful technique of spectrally resolved Thomson scattering can be extended to the x-ray regime, for direct measurements of the ionization state, density, temperature, and the microscopic behavior of dense cool plasmas. Such a direct measurement of microscopic parameters of solid density plasmas could eventually be used to properly interpret laboratory measurements of material properties such as thermal and electrical conductivity, EUS and opacity. In addition, x-ray Thomson scattering will provide new information on the characteristics of rarely and hitherto difficult to diagnose Fermi degenerate and strongly coupled plasmas.

  12. Simulation of laser bistatic two-dimensional scattering imaging about lambertian cylinders

    Science.gov (United States)

    Gong, Yanjun; Li, Lang; Wang, Mingjun; Gong, Lei

    2016-10-01

    This paper deals with the simulation of laser bi-static scattering imaging about lambertian cylinders. Two-dimensional imaging of a target can reflect the shape of the target and material property on the surface of the target. Two-dimensional imaging has important significance for target recognition. Simulations results of laser bi-static two-dimensional scattering imaging of some cylinders are given. The laser bi-static scattering imaging of cylinder, whose surface material with diffuse lambertian reflectance, is given in this paper. The scattering direction of laser bi-static scattering imaging is arbitrary direction. The scattering direction of backward two-dimensional scattering imaging is at opposite direction of the incident direction of laser. The backward two-dimensional scattering imaging is special case of bi-static two dimensional scattering imaging. The scattering intensity of a micro-element on the target could be obtained based on the laser radar equation. The intensity is related to local angle of incidence, local angle of scattering and the infinitesimal area on the surface of cylinder. According to the incident direction of incident laser and normal of infinitesimal area, the local incidence angle can be calculated. According to the scattering direction and normal of infinitesimal area, the local angle of scattering can be calculated. Through surface integration and the introduction of the rectangular function, we can get the intensity of imaging unit on the imaging surface, and then get mathematical model of bi-static laser two dimensional scattering imaging about lambert cylinder. From the results given, one can see that the simulation results of laser bi-static scattering about lambert cylinder is correct.

  13. Two-dimensional temperature determination in sooting flames by filtered Rayleigh scattering

    Science.gov (United States)

    Hoffman, D.; Münch, K.-U.; Leipertz, A.

    1996-04-01

    We present what to our knowledge are the first filtered Rayleigh scattering temperature measurements and use them in sooting flame. This new technique for two-dimensional thermography in gas combustion overcomes some of the major disadvantages of the standard Rayleigh technique. It suppresses scattered background light from walls or windows and permits detection of two-dimensional Rayleigh intensity distributions of the gas phase in the presence of small particles by spectral filtering of the scattered light.

  14. Gated integrator PXI-DAQ system for Thomson scattering diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Kiran, E-mail: kkpatel@ipr.res.in; Pillai, Vishal; Singh, Neha; Thomas, Jinto; Kumar, Ajai

    2017-06-15

    Gated Integrator (GI) PXI based data acquisition (DAQ) system has been designed and developed for the ease of acquiring fast Thomson Scattered signals (∼50 ns pulse width). The DAQ system consists of in-house designed and developed GI modules and PXI-1405 chassis with several PXI-DAQ modules. The performance of the developed system has been validated during the SST-1 campaigns. The dynamic range of the GI module depends on the integrating capacitor (C{sub i}) and the modules have been calibrated using 12 pF and 27 pF integrating capacitors. The developed GI module based data acquisition system consists of sixty four channels for simultaneous sampling using eight PXI based digitization modules having eight channels per module. The error estimation and functional tests of this unit are carried out using standard source and also with the fast detectors used for Thomson scattering diagnostics. User friendly Graphical User Interface (GUI) has been developed using LabVIEW on Windows platform to control and acquire the Thomson scattering signal. A robust, easy to operate and maintain with low power consumption, having higher dynamic range with very good sensitivity and cost effective DAQ system is developed and tested for the SST-1 Thomson scattering diagnostics.

  15. Thomson scattering at Pilot-PSI and Magnum-PSI

    NARCIS (Netherlands)

    van Rooij, G. J.; van der Meiden, H. J.; Hoen, Mhjt; Koppers, W. R.; Shumack, A. E.; Vijvers, W. A. J.; Westerhout, J.; Wright, G. M.; Rapp, J.

    2009-01-01

    A robust and sensitive Thomson scattering (TS) system has been developed for the high density low temperature plasma in the linear plasma generator Pilot-PSI, which routinely and reproducibly measures electron density and temperature profiles along a detection chord of 25 mm with a spatial

  16. Collective Thomson Scattering from Laser-Produced Plasmas

    Institute of Scientific and Technical Information of China (English)

    白波; 郑坚; 俞昌旋; 刘万东; 蒋小华; 袁晓东; 郑志坚; 徐冰; 向勇; 赵春茁

    2001-01-01

    Time-resolved Thomson scattering was successfully performed to diagnose the parameters (ZTe, Ue and Ui) of laser-produced gold plasma. The results show that the collisionless dynamic form factor is accurate enough to be used for reducing the plasma parameters from the experimental data.

  17. Collective Thomson scattering measurements with high frequency resolution at TEXTOR

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Korsholm, Søren Bang

    2010-01-01

    We discuss the development and first results of a receiver system for the collective Thomson scattering (CTS) diagnostic at TEXTOR with frequency resolution in the megahertz range or better. The improved frequency resolution expands the diagnostic range and utility of CTS measurements in general...

  18. Collective Thomson scattering capabilities to diagnose fusion plasmas

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  19. Effect of anisotropic scattering on radiative heat transfer in two-dimensional rectangular media

    CERN Document Server

    Hao Jin Bo

    2003-01-01

    Effect of scattering on radiative heat transfer in two-dimensional rectangular media by the finite-volume method has been studied. Compared with the existing solutions, it shows that the result obtained by the finite-volume method is reliable. Furthermore, relative errors caused by the approximation that linear and nonlinear anisotropic scattering media is simplified to isotropic scattering media have been studied.

  20. Calculation of Thomson scattering spectral fits for interpenetrating flows

    Science.gov (United States)

    Swadling, G. F.; Lebedev, S. V.; Harvey-Thompson, A. J.; Rozmus, W.; Burdiak, G. C.; Suttle, L.; Patankar, S.; Smith, R. A.; Bennett, M.; Hall, G. N.; Suzuki-Vidal, F.; Yuan, J.

    2014-12-01

    Collective mode optical Thomson scattering has been used to investigate the interactions of radially convergent ablation flows in Tungsten wire arrays. These experiments were carried out at the Magpie pulsed power facility at Imperial College, London. Analysis of the scattered spectra has provided direct evidence of ablation stream interpenetration on the array axis, and has also revealed a previously unobserved axial deflection of the ablation streams towards the anode as they approach the axis. It is has been suggested that this deflection is caused by the presence of a static magnetic field, advected with the ablation streams, stagnated and accrued around the axis. Analysis of the Thomson scattering spectra involved the calculation and fitting of the multi-component, non-relativistic, Maxwellian spectral density function S (k, ω). The method used to calculate the fits of the data are discussed in detail.

  1. Calculation of Thomson scattering spectral fits for interpenetrating flows

    Energy Technology Data Exchange (ETDEWEB)

    Swadling, G. F., E-mail: george.swadling@imperial.ac.uk; Lebedev, S. V., E-mail: george.swadling@imperial.ac.uk; Burdiak, G. C.; Suttle, L.; Patankar, S.; Smith, R. A.; Bennett, M.; Suzuki-Vidal, F. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Harvey-Thompson, A. J. [Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185-1193 (United States); Rozmus, W. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2JI (Canada); Hall, G. N. [Blackett Laboratory, Imperial College, London, United Kingdom SW7 2BW and Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Yuan, J. [Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAE, Mianyang 621900 (China)

    2014-12-15

    Collective mode optical Thomson scattering has been used to investigate the interactions of radially convergent ablation flows in Tungsten wire arrays. These experiments were carried out at the Magpie pulsed power facility at Imperial College, London. Analysis of the scattered spectra has provided direct evidence of ablation stream interpenetration on the array axis, and has also revealed a previously unobserved axial deflection of the ablation streams towards the anode as they approach the axis. It is has been suggested that this deflection is caused by the presence of a static magnetic field, advected with the ablation streams, stagnated and accrued around the axis. Analysis of the Thomson scattering spectra involved the calculation and fitting of the multi-component, non-relativistic, Maxwellian spectral density function S (k, ω). The method used to calculate the fits of the data are discussed in detail.

  2. Imaging X-ray Thomson Scattering Spectrometer Design and Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Gamboa, E.J. [University of Michigan; Huntington, C.M. [University of Michigan; Trantham, M.R. [University of Michigan; Keiter, P.A [University of Michigan; Drake, R.P. [University of Michigan; Montgomery, David [Los Alamos National Laboratory; Benage, John F. [Los Alamos National Laboratory; Letzring, Samuel A. [Los Alamos National Laboratory

    2012-05-04

    In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering is a powerful technique for measuring these plasma parameters. However, the scattered signal has previously been measured with little or no spatial resolution, which limits the ability to diagnose inhomogeneous plasmas. We report on the development of a new imaging x-ray Thomson spectrometer (IXTS) for the Omega laser facility. The diffraction of x-rays from a toroidally-curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile while spectrally dispersing the radiation. This focusing geometry allows for high brightness while localizing noise sources and improving the linearity of the dispersion. Preliminary results are presented from a scattering experiment that used the IXTS to measure the temperature profile of a shocked carbon foam.

  3. Upgraded divertor Thomson scattering system on DIII-D

    Science.gov (United States)

    Glass, F.; Carlstrom, T. N.; Du, D.; McLean, A. G.; Taussig, D. A.; Boivin, R. L.

    2016-11-01

    A design to extend the unique divertor Thomson scattering system on DIII-D to allow measurements of electron temperature and density in high triangularity plasmas is presented. Access to this region is selectable on a shot-by-shot basis by redirecting the laser beam of the existing divertor Thomson system inboard — beneath the lower floor using a moveable, high-damage threshold, in-vacuum mirror — and then redirecting again vertically. The currently measured divertor region remains available with this mirror retracted. Scattered light is collected from viewchords near the divertor floor using in-vacuum, high temperature optical elements and relayed through the port window, before being coupled into optical fiber bundles. At higher elevations from the floor, measurements are made by dynamically re-focusing the existing divertor system collection optics. Nd:YAG laser timing, analysis of the scattered light spectrum via polychromators, data acquisition, and calibration are all handled by existing systems or methods of the current multi-pulse Thomson scattering system. Existing filtered polychromators with 7 spectral channels are employed to provide maximum measurement breadth (Te in the range of 0.5 eV-2 keV, ne in the range of 5 × 1018-1 × 1021 m3) for both low Te in detachment and high Te measurement up beyond the separatrix.

  4. Upgraded divertor Thomson scattering system on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Glass, F., E-mail: glassf@fusion.gat.com; Carlstrom, T. N.; Du, D.; Taussig, D. A.; Boivin, R. L. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); McLean, A. G. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

    2016-11-15

    A design to extend the unique divertor Thomson scattering system on DIII-D to allow measurements of electron temperature and density in high triangularity plasmas is presented. Access to this region is selectable on a shot-by-shot basis by redirecting the laser beam of the existing divertor Thomson system inboard — beneath the lower floor using a moveable, high-damage threshold, in-vacuum mirror — and then redirecting again vertically. The currently measured divertor region remains available with this mirror retracted. Scattered light is collected from viewchords near the divertor floor using in-vacuum, high temperature optical elements and relayed through the port window, before being coupled into optical fiber bundles. At higher elevations from the floor, measurements are made by dynamically re-focusing the existing divertor system collection optics. Nd:YAG laser timing, analysis of the scattered light spectrum via polychromators, data acquisition, and calibration are all handled by existing systems or methods of the current multi-pulse Thomson scattering system. Existing filtered polychromators with 7 spectral channels are employed to provide maximum measurement breadth (T{sub e} in the range of 0.5 eV–2 keV, n{sub e} in the range of 5 × 10{sup 18}–1 × 10{sup 21} m{sup 3}) for both low T{sub e} in detachment and high T{sub e} measurement up beyond the separatrix.

  5. Laser bistatic two-dimensional scattering imaging simulation of lambert cone

    Science.gov (United States)

    Gong, Yanjun; Zhu, Chongyue; Wang, Mingjun; Gong, Lei

    2015-11-01

    This paper deals with the laser bistatic two-dimensional scattering imaging simulation of lambert cone. Two-dimensional imaging is called as planar imaging. It can reflect the shape of the target and material properties. Two-dimensional imaging has important significance for target recognition. The expression of bistatic laser scattering intensity of lambert cone is obtained based on laser radar eauqtion. The scattering intensity of a micro-element on the target could be obtained. The intensity is related to local angle of incidence, local angle of scattering and the infinitesimal area on the cone. According to the incident direction of laser, scattering direction and normal of infinitesimal area, the local incidence angle and scattering angle can be calculated. Through surface integration and the introduction of the rectangular function, we can get the intensity of imaging unit on the imaging surface, and then get Lambert cone bistatic laser two-dimensional scattering imaging simulation model. We analyze the effect of distinguishability, incident direction, observed direction and target size on the imaging. From the results, we can see that the scattering imaging simulation results of the lambert cone bistatic laser is correct.

  6. Thomson scattering diagnostic for the measurement of ion species fraction

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J S; Park, H S; Amendt, A; Divol, L; Kugland, N L; Rozmus, W; Glenzer, S H

    2012-05-01

    Simultaneous Thomson scattering measurements of collective electron-plasma and ion-acoustic fluctuations have been utilized to determine ion species fraction from laser produced CH plasmas. The CH{sub 2} foil is heated with 10 laser beams, 500 J per beam, at the Omega Laser facility. Thomson scattering measurements are made 4 mm from the foil surface using a 30 J 2{omega} probe laser with a 1 ns pulse length. Using a series of target shots the plasma evolution is measured from 2.5 ns to 9 ns after the rise of the heater beams. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the two-ion species theoretical form factor for the ion feature such that the ion temperature, plasma flow velocity and ion species fraction are determined. The ion species fraction is determined to an accuracy of {+-}0.06 in species fraction.

  7. Warm dense matter and Thomson scattering at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Faeustlin, Roland Rainer

    2010-05-15

    X-ray free electron lasers are powerful tools to investigate moderately to strongly correlated solid density low temperature plasmas, named warm dense matter. These plasmas are of most interest for astrophysics and laser plasma interaction, particularly inertial confinement fusion. This work utilizes the ultrashort soft x-ray pulse duration and high brilliance of the free electron laser in Hamburg, FLASH, to generate warm dense matter and to study its ultrafast processes. The techniques applied are absorption measurement, emission spectroscopy and Thomson scattering. Radiative hydrodynamics and Thomson scattering simulations are used to investigate the impact of temperature and density gradients in the sample and to fit the experimental data. The measurements result in a comprehensive picture of soft x-ray matter interaction related to warm dense matter and yield insight into ultrafast equilibration and relaxation mechanisms, in particular impact ionization and radiative recombination. (orig.)

  8. 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....

  9. Enhancing detection sensitivity of SST-1 Thomson scattering experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhari, Vishnu; Patel, Kiran; Thomas, Jinto; Kumar, Ajai, E-mail: ajai@ipr.res.in

    2016-10-15

    Thomson Scattering System (TSS) is the main diagnostic to extract electron temperature and density of steady state superconducting (SST-1) tokamak plasma. Silicon avalanche photo diode is used with low noise and fast signal conditioning electronics (SCE) to detect incoming Thomson scattered laser photons. A stringent requirement for the measurement is to detect high speed and low level light signal (detection of 100 numbers of Thomson scattered photons for 50 ns pulse width at input of active area of detector) in the presence of wide band electro-magnetic interference (EMI) noise. The electronics and instruments for different sub-systems kept in laboratory contribute to the radiated and conductive noise in a complex manner to the experiment, which can degrade the resultant signal to noise ratio (SNR <1). In general a repeated trial method with flexible grounding scheme are used to improve system signal to noise ratio, which is time consuming and less efficient. In the present work a simple, robust, cost-effective instrumentation system is used for the measurement and monitoring with improved ground scheme and shielding method to minimize noise, isolating the internal sub-system generated noise and external interference which leads to an improved SNR.

  10. ITER Fast Ion Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Larsen, Axel Wright; Meo, Fernando;

    2005-01-01

    velocities with good spatial and temporal resolution. The present report, which is a continuation of this work, presents a detailed CATIA design of the two antennae systems, modified and extended calculations on beam overlap and scattering, measurements and calculations of the beam transmission through...

  11. Laser Thomson scattering in a pulsed atmospheric arc discharge

    Science.gov (United States)

    Sommers, Bradley; Adams, Steven

    2015-09-01

    Laser scattering measurements, including Rayleigh, Raman, and Thomson scattering have been performed on an atmospheric pulsed arc discharge. Such laser scattering techniques offer a non-invasive diagnostic to measure gas temperature, electron temperature, and electron density in atmospheric plasma sources, particularly those with feature sizes approaching 1 mm. The pulsed discharge is ignited in a pin to pin electrode geometry using a 6 kV pulse with 10 ns duration. The electrodes are housed in a glass vacuum chamber filled with argon gas. The laser signal is produced by a Nd:Yag laser supply, repetitively pulsed at 10 Hz and frequency quadrupled to operate at 266 nm. The scattered laser signal is imaged onto a triple grating spectrometer, which is used to suppress the Rayleigh scatter signal in order to measure the low amplitude Thomson and Raman signals. Preliminary results include measurements of electron temperature and electron density in the plasma column taken during the evolution of the discharge. The laser system is also used to measure the Rayleigh scattering signal, which provides space and time resolved measurements of gas temperature in the arc discharge.

  12. APD detector electronics for the NSTX Thomson scattering system

    Energy Technology Data Exchange (ETDEWEB)

    D.W. Johnson; B.P. LeBlanc; D.L. Long; G. Renda

    2000-08-07

    An electronics system has been installed and tested for the readout of APD detectors for the NSTX Thomson scattering system. Similar to previous designs, it features preamps with a fast and a slow output. The fast output uses pulse shaping to optimize sensitivity for the 8 nsec scattered light pulse while rejecting noise in the intrinsic plasma background. A low readout noise of {approximately}25 photoelectrons is achieved at an APD gain of 75. The design incorporates a number of features to provide flexibility for various modes of calibration.

  13. Elastic Wave Scattering by Two-Dimensional Periodical Array of Cylinders

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We extend the multiple-scattering theory (MST) for elastic wave scattering and propagating in two-dimensional composite. The formalism for the band structure calculation is presented by taking into account the full vector character of the elastic wave. As a demonstration of application of the formalism, we calculate the band structure of elastic wave propagating in a two-dimensional periodic arrangement of cylinders. The results manifest that the MST shows great promise in complementing the plane-wave (PW) approach for the study of elastic wave.

  14. Development of prototype polychromator system for KSTAR Thomson scattering diagnostic

    Science.gov (United States)

    Lee, J. H.; Lee, S. H.; Son, S. H.; Ko, W. H.; Seo, D. C.; Yamada, I.; Her, K. H.; Jeon, J. S.; Bog, M. G.

    2015-12-01

    A polychromator is widely used by the Thomson scattering system for measuring the electron temperature and density. This type of spectrometer includes optic elements such as band-pass filters, focusing lens, collimating lens, and avalanche photodiodes (APDs). The characteristics of band-pass filters in the polychromator are determined by the measuring range of the Thomson system. KSTAR edge polychromators were developed by co-works at NIFS in Japan, and the KSTAR core polychromators were developed by NFRI in Korea. The power supply system of these polychromators is connected only to one power supply module and can manually control the APD's voltage at the front side of the power supply by using a potentiometer. In this paper, a prototype polychromator is introduced at the KSTAR. The prototype polychromator system has a built-in power supply unit that includes high voltage for the APD and ± 5 V for an op-amp IC. The high voltage for the APD is finely controlled and monitored using a PC with the LabView software. One out of the six band pass-filters has a center wavelength of 523.5 nm with 2-nm bandwidth, which can measure Zeff, and the other five band-pass filters can simultaneously measure the Thomson signal. In addition, we will show the test result of this prototype polychromator system during the KSTAR experiment campaign (2015).

  15. Thomson scattering diagnostic on the Compact Toroidal Hybrid Experiment

    Science.gov (United States)

    Traverso, Peter; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.

    2016-10-01

    A Thomson scattering system is being commissioned for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH), a five-field period current-carrying torsatron. The system takes a single point measurement at the magnetic axis to both calibrate the two- color soft x-ray Te system and serve as an additional diagnostic for the V3FIT 3D equilibrium reconstruction code. A single point measurement will reduce the uncertainty in the reconstructed peak pressure by an order of magnitude for both current-carrying plasmas and future gyrotron-heated stellarator plasmas. The beam, generated by a frequency doubled Continuum 2 J, Nd:YaG laser, is passed vertically through an entrance Brewster window and a two-aperture optical baffle system to minimize stray light. The beam line propagates 8 m to the CTH device mid-plane with the beam diameter < 3 mm inside the plasma volume. Thomson scattered light is collected by two adjacent f/2 plano-convex condenser lenses and focused onto a custom fiber bundle. The fiber is then re-bundled and routed to a Holospec f/1.8 spectrograph to collect the red-shifted scattered light from 535-565 nm. The system has been designed to measure plasmas with core Te of 100 to 200 eV and densities of 5 ×1018 to 5 ×1019 m-3. Work supported by USDOE Grant DE-FG02-00ER54610.

  16. On the calibration of polarimetric Thomson scattering by Raman polarimetry

    Science.gov (United States)

    Giudicotti, L.; Pasqualotto, R.

    2015-12-01

    Polarimetric Thomson scattering (TS) is an alternative method for the analysis of Thomson scattering spectra in which the plasma temperature T e is determined from the depolarization of the TS radiation. This is a relativistic effect and therefore the technique is suitable only for very hot plasmas (T e  >  10 keV) such as those of ITER. The practical implementation of polarimetric TS requires a method to calibrate the polarimetric response of the collection optics carrying the TS light to the detection system, and in particular to measure the additional depolarization of the TS radiation introduced by the plasma-exposed first mirror. Rotational Raman scattering of laser light from diatomic gases such as H2, D2, N2 and O2 can provide a radiation source of predictable intensity and polarization state from a well-defined volume inside the vacuum vessel and is therefore suitable for these calibrations. In this paper we discuss Raman polarimetry as a technique for the calibration of a hypothetical polarimetric TS system operating in the same conditions of the ITER core TS system and suggest two calibration methods for the measurement of the additional depolarization introduced by the plasma-exposed first mirror, and in general for calibrating the polarimetric response of the detection system.

  17. Imaging Thomson scattering measurements of radiatively heated Xe

    Energy Technology Data Exchange (ETDEWEB)

    Pollock, B; Meinecke, J; Kuschel, S; Ross, J S; Divol, L; Glenzer, S H; Tynan, G R

    2012-05-01

    Uniform density and temperature Xe plasmas have been produced over >4 mm scale-lengths using x-rays generated in a cylindrical Pb cavity. The cavity is 750 {micro}m in depth and diameter, and is heated by a 300 J, 2 ns square, 1054 nm laser pulse focused to a spot size of 200 {micro}m at the cavity entrance. The plasma is characterized by simultaneous imaging Thomson scattering measurements from both the electron and ion scattering features. The electron feature measurement determines the spatial electron density and temperature profile, and using these parameters as constraints in the ion feature analysis allows an accurate determination of the charge state of the Xe ions. The Thomson scattering probe beam is 40 J, 200 ps, and 527 nm, and is focused to a 100 {micro}m spot size at the entrance of the Pb cavity. Each system has a spatial resolution of 25 {micro}m, a temporal resolution of 200 ps (as determined by the probe duration), and a spectral resolution of 2 nm for the electron feature system and 0.025 nm for the ion feature system. The experiment is performed in a Xe filled target chamber at a neutral pressure of 3-10 Torr, and the x-rays produced in the Pb ionize and heat the Xe to a charge state of 20 {+-} 4 at up to 200 eV electron temperatures.

  18. Polychromator for the edge Thomson scattering system in ITER.

    Science.gov (United States)

    Yatsuka, E; Hatae, T; Fujie, D; Kurokawa, A; Kusama, Y

    2012-10-01

    A new type polychromator has been designed for the edge Thomson scattering system in ITER. Signal light is parallelly dispersed into two parts at the first interference filter. Spectral transmissivities for some spectral channels may enhance better than the conventional type polychromator. In the new type polychromator, the misalignment due to the machine accuracy is expected to be within the margin of APD area. In order to calibrate the spectral transmissivity using the dual-laser injection method during the plasma discharge, it is preferred that the spectral channels are separated at the geometric mean of the injected two wavelengths.

  19. Peak intensity measurement of relativistic lasers via nonlinear Thomson scattering

    CERN Document Server

    Har-Shemesh, Omri

    2011-01-01

    The measurement of peak laser intensities exceeding $10^{20}\\;\\text{W/cm$^2$}$ is in general a very challenging task. We suggest a simple method to accurately measure such high intensities up to about $10^{23}\\,\\text{W/cm$^2$}$, by colliding a beam of ultrarelativistic electrons with the laser pulse. The method exploits the specific features of the angular distribution of the radiation emitted by ultrarelativistic electrons via nonlinear Thomson scattering. Initial electron energies well within the reach of laser wake-field accelerators are required, allowing in principle for an all-optical setup. Accuracies of the order of 10% are envisaged.

  20. Collective Thomson scattering data analysis for Wendelstein 7-X

    DEFF Research Database (Denmark)

    Abramovic, I.; Pavone, A.; Svensson, J.

    2017-01-01

    Collective Thomson scattering (CTS) diagnostic is being installed on the Wendelstein 7-X stellarator to measure the bulk ion temperature in the upcoming experimental campaign. In order to prepare for the data analysis, a forward model of the diagnostic (eCTS) has been developed and integrated...... into the Bayesian data analysis framework Minerva. Synthetic spectra have been calculated with the forward model and inverted using Minerva in order to demonstrate the feasibility to measure the ion temperature in the presence of nuisance parameters that also influence CTS spectra. In this paper we report...... on the results of this anlysis and discuss the main sources of uncertainty in the CTS data analysis....

  1. Observation of Thomson Scattering off Entropy Waves in a Laser-Produced Plasma

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jian; BAI Bo; LIU Wan-Dong; YU Chang-Xuan; JIANG Xiao-Hua; YUAN Xiao-Dong; LI Wen-Hong; ZHENG Zhi-Jian

    2001-01-01

    A new feature in the Thomson scattering spectrum is observed from a laser-produced aluminium plasma, which may be the Thomson scattering off entropy waves in the plasma. Such a feature is only observable when the energy of the heater beam is low enough.

  2. Structures in T-e profiles: High resolution Thomson scattering in the Rijnhuizen tokamak project

    NARCIS (Netherlands)

    Beurskens, M. N. A.; Barth, C. J.; Cardozo, N. J. L.; van der Meiden, H. J.; R. T. P. Team,

    1999-01-01

    In the Rijnhuizen tokamak project, the double pulse multiposition Thomson scattering diagnostic is in full operation. Its high spatial resolution enables the measurement of small scale structures in T-e, n(e), and p(e). Thomson scattering profiles during an ordinary sawtooth crash show the displacem

  3. Multipoint Thomson scattering diagnostic for the ETE tokamak

    Science.gov (United States)

    Berni, L. A.; Alonso, M. P.; Oliveira, R. M.

    2004-10-01

    To measure the electron temperature and plasma density profiles on the Experimento Tokamak Esférico tokamak a multiplexed Thomson scattering diagnostic was implemented. The diagnostic is based on a 10 J ruby laser and a single five spectral channel filter polychromator. A collection lens with f/6.3 relay the scattered light from 23 spatial points to optical fibers. The fibers have a monotonous increasing length and are inserted into the polychromator. Between the collection lens and each fiber optic we have a microlens to match the numerical aperture and to enlarge the plasma observation volume. This work describes the project, the simulations, and the preliminary results obtained with the first four optical fibers.

  4. The Thomson scattering system at Wendelstein 7-X

    Science.gov (United States)

    Pasch, E.; Beurskens, M. N. A.; Bozhenkov, S. A.; Fuchert, G.; Knauer, J.; Wolf, R. C.

    2016-11-01

    This paper describes the design of the Thomson scattering system at the Wendelstein 7-X stellarator. For the first operation campaign we installed a 10 spatial channel system to cover a radial half profile of the plasma cross section. The start-up system is based on one Nd:YAG laser with 10 Hz repetition frequency, one observation optics, five fiber bundles with one delay line each, and five interference filter polychromators with five spectral channels and silicon avalanche diodes as detectors. High dynamic range analog to digital converters with 14 bit, 1 GS/s are used to digitize the signals. The spectral calibration of the system was done using a pulsed super continuum laser together with a monochromator. For density calibration we used Raman scattering in nitrogen gas. Peaked temperature profiles and flat density profiles are observed in helium and hydrogen discharges.

  5. Design of Thomson scattering diagnostic system on J-TEXT

    Science.gov (United States)

    Zhou, Yinan; Gao, Li; Huang, Jiefeng; Qiu, Qingshuang; Zhuang, Ge

    2016-11-01

    An infrared multi-channel Thomson scattering diagnostic system is designed from the viewpoint of development of the proposed system on the Joint Texas Experimental Tokamak (J-TEXT). A 3 J/50 Hz Nd:YAG laser, which is injected vertically into plasma in the direction from top to bottom, serves as the power source of the system. The scattering light is then collected horizontally and is transmitted to an interference-filter avalanche photodiode based polychromater for spectrum analysis. The system covers the half plasma cross section, providing 14 spatial points with 2 cm resolution. The proposed system can thus satisfy the requirements of the J-TEXT at present and in the near future. A detailed description of the system design is presented in this paper.

  6. Design of Thomson scattering diagnostic system on J-TEXT.

    Science.gov (United States)

    Zhou, Yinan; Gao, Li; Huang, Jiefeng; Qiu, Qingshuang; Zhuang, Ge

    2016-11-01

    An infrared multi-channel Thomson scattering diagnostic system is designed from the viewpoint of development of the proposed system on the Joint Texas Experimental Tokamak (J-TEXT). A 3 J/50 Hz Nd:YAG laser, which is injected vertically into plasma in the direction from top to bottom, serves as the power source of the system. The scattering light is then collected horizontally and is transmitted to an interference-filter avalanche photodiode based polychromater for spectrum analysis. The system covers the half plasma cross section, providing 14 spatial points with 2 cm resolution. The proposed system can thus satisfy the requirements of the J-TEXT at present and in the near future. A detailed description of the system design is presented in this paper.

  7. Thomson Scattering Diagnostic Data Acquisition Systems for Modern Fusion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ivanenko, S.V.; Khilchenko, A.D. [Budker Institute of Nuclear Physics and Novosibirsk State University, Novosibirsk (Russian Federation); Ovchar, V.K.; Zubarev, P.V.; Kvashnin, A.N.; Puryga, E.A.; Ivanova, A.A.; Kotelnikov, A.I. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    2015-07-01

    Uniquely designed complex data acquisition system for Thomson scattering diagnostic was developed. It allows recording short duration (3-5 ns) scattered pulses with 2 GHz sampling rate and 10-bit total resolution in oscilloscope mode. The system consists up to 48 photo detector modules with 0- 200 MHz bandwidth, 1-48 simultaneously sampling ADC modules and synchronization subsystem. The photo detector modules are based on avalanche photodiodes (APD) and ultra-low noise trans-impedance amplifiers. ADC modules include fast analog to digital converters and digital units based on the FPGA (Field- Programmable Gate Array) for data processing and storage. The synchronization subsystem is used to form triggering pulses and to organize the simultaneously mode of ADC modules operation. (authors)

  8. Short-pulsed laser transport in two-dimensional scattering media by natural element method.

    Science.gov (United States)

    Zhang, Yong; Yi, Hong-Liang; Xie, Ming; Tan, He-Ping

    2014-04-01

    The natural element method (NEM) is extended to solve transient radiative transfer (TRT) in two-dimensional semitransparent media subjected to a collimated short laser irradiation. The least-squares (LS) weighted residuals approach is employed to spatially discretize the transient radiative heat transfer equation. First, for the case of the refractive index matched boundary, LSNEM solutions to TRT are validated by comparison with results reported in the literature. Effects of the incident angle on time-resolved signals of transmittance and reflectance are investigated. Afterward, the accuracy of this algorithm for the case of the refractive index mismatched boundary is studied. Finally, the LSNEM is extended to study the TRT in a two-dimensional semitransparent medium with refractive index discontinuity irradiated by the short pulse laser. The effects of scattering albedo, optical thickness, scattering phase function, and refractive index on transmittance and reflectance signals are investigated. Several interesting trends on the time-resolved signals are observed and analyzed.

  9. Solution of two-dimensional scattering problem in piezoelectric/piezomagnetic media using a polarization method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Using a polarization method, the scattering problem for a two-dimensional inclusion embedded in infinite piezoelectric/piezomagnetic matrices is investigated. To achieve the purpose, the polarization method for a two-dimensional piezoelectric/piezo-magnetic "comparison body" is formulated. For simple harmonic motion, kernel of the polarization method reduces to a 2-D time-harmonic Green's function, which is ob-tained using the Radon transform. The expression is further simplified under condi-tions of low frequency of the incident wave and small diameter of the inclusion. Some analytical expressions are obtained. The analytical solutions for generalized piezoelec-tric/piezomagnetic anisotropic composites are given followed by simplified results for piezoelectric composites. Based on the latter results, two numerical results are provided for an elliptical cylindrical inclusion in a PZT-5H-matrix, showing the effect of different factors including size, shape, material properties, and piezoelectricity on the scattering cross-section.

  10. Scattering of Fexural Gravity Waves by a Two-Dimensional Thin Plate

    Directory of Open Access Journals (Sweden)

    Sudeshna Banerjee

    2017-01-01

    Full Text Available An approximate analysis based on standard perturbation technique together with an application of Green’s integral theorem is used in this paper to study the problem of scattering of water waves by a two dimensional thin plate submerged in deep ocean with ice cover. The reflection and transmission coefficients upto first order are obtained in terms of the shape function describing the plate and are studied graphically for different shapes of the plate.

  11. On t-local solvability of inverse scattering problems in two-dimensional layered media

    Science.gov (United States)

    Baev, A. V.

    2015-06-01

    The solvability of two-dimensional inverse scattering problems for the Klein-Gordon equation and the Dirac system in a time-local formulation is analyzed in the framework of the Galerkin method. A necessary and sufficient condition for the unique solvability of these problems is obtained in the form of an energy conservation law. It is shown that the inverse problems are solvable only in the class of potentials for which the stationary Navier-Stokes equation is solvable.

  12. TFTR 60 GHz alpha particle collective Thomson Scattering diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Machuzak, J.S.; Woskov, P.P.; Gilmore, J. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Bretz, N.L.; Park, H.K. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Aamodt, R.E.; Cheung, P.Y.; Russell, D.A. [Lodestar Research Corp., Boulder, CO (United States); Bindslev, H. [JET Joint Undertaking, Abingdon (United Kingdom)

    1995-03-01

    A 60 GHz gyrotron collective Thomson Scattering alpha particle diagnostic has been implemented for the D-T period on TFM. Gyrotron power of 0.1-1 kW in pulses of up to 1 second can be launched in X-mode. Efficient corrugated waveguides are used with antennaes and vacuum windows of the TFTR Microwave Scattering system. A multichannel synchronous detector receiver system and spectrum analyzer acquire the scattered signals. A 200 Megasample/sec digitizer is used to resolve fine structure in the frequency spectrum. By scattering nearly perpendicular to the magnetic field, this experiment will take advantage of an enhancement of the scattered signal which results from the interaction of the alpha particles with plasma resonances in the lower hybrid frequency range. Significant enhancements are expected, which will make these measurements possible with gyrotron power less than 1 kW, while maintaining an acceptable signal to noise ratio. We hope to extract alpha particle density and velocity distribution functions from the data. The D and T fuel densities and temperatures may also be obtainable by measurement of the respective ion cyclotron harmonic frequencies.

  13. A Convergent Method of Auxiliary Sources for Two-Dimensional Impedance Scatterers With Edges

    DEFF Research Database (Denmark)

    Karamehmedovic, Mirza; Breinbjerg, Olav

    2001-01-01

    A modification to the Method of Auxiliary Sources (MAS) is introduced which renders the method operational for two-dimensional impedance scatterers with edges. The modification consists in letting the auxiliary surface converge to the scatterer physical surface for increasing number of auxiliary...... sources, whereby MAS approaches a surface integral equation (IE) method. Hereby, a systematic procedure for selecting the number and locations of the auxiliary sources is provided, and convergence of numerical results is obtained. The new method resulting from this modification thus combines the desirable...

  14. Thomson scattering measurements from asymmetric interpenetrating plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J. S., E-mail: ross36@llnl.gov; Moody, J. D.; Fiuza, F.; Ryutov, D.; Divol, L.; Huntington, C. M.; Park, H.-S. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

    2014-11-15

    Imaging Thomson scattering measurements of collective ion-acoustic fluctuations have been utilized to determine ion temperature and density from laser produced counter-streaming asymmetric flows. Two foils are heated with 8 laser beams each, 500 J per beam, at the Omega Laser facility. Measurements are made 4 mm from the foil surface using a 60 J 2ω probe laser with a 200 ps pulse length. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the multi-ion species, asymmetric flows theoretical form factor for the ion feature such that the ion temperatures, ion densities, and flow velocities for each plasma flow are determined.

  15. Thomson scattering in high-intensity chirped laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Holkundkar, Amol R., E-mail: amol.holkundkar@pilani.bits-pilani.ac.in [Department of Physics, Birla Institute of Technology and Science, Pilani, Rajasthan 333031 (India); Harvey, Chris, E-mail: christopher.harvey@chalmers.se; Marklund, Mattias, E-mail: mattias.marklund@chalmers.se [Department of Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden)

    2015-10-15

    We consider the Thomson scattering of an electron in an ultra-intense laser pulse. It is well known that at high laser intensities, the frequency and brilliance of the emitted radiation will be greatly reduced due to the electron losing energy before it reaches the peak field. In this work, we investigate the use of a small frequency chirp in the laser pulse in order to mitigate this effect of radiation reaction. It is found that the introduction of a negative chirp means the electron enters a high frequency region of the field while it still has a large proportion of its original energy. This results in a significant enhancement of the frequency and intensity of the emitted radiation as compared to the case without chirping.

  16. Simultaneous two-color, two-dimensional angular optical scattering patterns from airborne particulates: Scattering results and exploratory analysis

    Science.gov (United States)

    Holler, Stephen; Fuerstenau, Stephen D.; Skelsey, Charles R.

    2016-07-01

    Light scattering from non-spherical particles and aggregates exhibits complex structure that is revealed only when observed in two angular dimensions (θ, ϕ). However, due to variations in shape, packing, and orientation of such aerosols, the structure of two-dimensional angular optical scattering (TAOS) patterns varies among particles. The spectral dependence of scattering contributes further to the observed complexity, but offers another facet to consider. By leveraging multispectral TAOS data from flowing aerosols, we have identified novel morphological descriptors that may be employed in multivariate statistical algorithms for "unknown" particle classification.

  17. A two-dimensionally focusing, quasi-optical antenna for millimeter-wave scattering in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Idehara, T.; Tatsukawa, T. (Faculty of Engineering, Fukui University, Fukui 910, Japan (JP)); Brand, G.F.; Fekete, P.W.; Moore, K.J. (School of Physics, University of Sydney, NSW 2006 (Australia))

    1990-06-01

    A two-dimensionally focusing, quasi-optical antenna having one elliptical reflector and one parabolic reflector has been built for use with a tunable gyrotron in order to carry out millimeter-wave scattering measurements on the TORTUS tokamak plasma at the University of Sydney. The advantages of this antenna are the following: (1) The elliptical reflector focuses the radiation beam in the toroidal direction, while the parabolic reflector focuses in the direction of major radius. This gives excellent two-dimensional focusing in the plasma region, and consequently excellent spatial resolution. (2) The focal point can be easily swept along the direction of major radius in the whole plasma region, simply by changing the angle of the parabolic reflector by a small amount. These features have been demonstrated experimentally using the tunable gyrotron source, GYROTRON III, and in computations of the radiated fields.

  18. Plasma characterization using ultraviolet Thomson scattering from ion-acoustic and electron plasma waves (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Follett, R. K., E-mail: rfollett@lle.rochester.edu; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States)

    2016-11-15

    Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 10{sup 21} cm{sup −3}, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.

  19. Plasma characterization using ultraviolet Thomson scattering from ion-acoustic and electron plasma waves (invited)

    Science.gov (United States)

    Follett, R. K.; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H.

    2016-11-01

    Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 1021 cm-3, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.

  20. Fiber-optic interferometric two-dimensional scattering-measurement system.

    Science.gov (United States)

    Zhu, Yizheng; Giacomelli, Michael G; Wax, Adam

    2010-05-15

    We present a fiber-optic interferometric system for measuring depth-resolved scattering in two angular dimensions using Fourier-domain low-coherence interferometry. The system is a unique hybrid of the Michelson and Sagnac interferometer topologies. The collection arm of the interferometer is scanned in two dimensions to detect angular scattering from the sample, which can then be analyzed to determine the structure of the scatterers. A key feature of the system is the full control of polarization of both the illumination and the collection fields, allowing for polarization-sensitive detection, which is essential for two-dimensional angular measurements. System performance is demonstrated using a double-layer microsphere phantom. Experimental data from samples with different sizes and acquired with different polarizations show excellent agreement with Mie theory, producing structural measurements with subwavelength accuracy.

  1. Conceptual design of a polarimetric Thomson scattering diagnostic in ITER

    Science.gov (United States)

    Giudicotti, L.; Bassan, M.; Orsitto, F. P.; Pasqualotto, R.; Kempenaars, M.; Flanagan, J.

    2016-01-01

    Polarimetric Thomson scattering (TS) is a novel diagnostic technique proposed as an alternative to conventional (spectral) TS, for the measurement of the electron temperature Te and density ne in very hot fusion plasmas. Contrary to spectral TS, which is based on the reconstruction of the Doppler broadened frequency spectrum, in polarimetric TS Te is determined from the depolarization of the scattered radiation. The technique is suitable for ITER, where it is expected to be competitive with conventional spectral TS for measurements in the highest Te range, specially in backward-like conditions with the scattering angle 90° ll θ measured Te and ne that can be obtained with a simple, two-channel polarimeter, and taking into account that only a fraction of the TS wavelength spectrum is detected. In both cases the expected performances are compared with those of the conventional spectral core TS diagnostic to determine the plasma conditions in which the polarimetric technique is more advantageous. A measurement of the depolarization effect of the TS radiation using the JET High Resolution TS system of JET is also discussed.

  2. Image Reconstruction of Two-Dimensional Highly Scattering Inhomogeneous Medium Using MAP-Based Estimation

    Directory of Open Access Journals (Sweden)

    Hong Qi

    2015-01-01

    Full Text Available A maximum a posteriori (MAP estimation based on Bayesian framework is applied to image reconstruction of two-dimensional highly scattering inhomogeneous medium. The finite difference method (FDM and conjugate gradient (CG algorithm serve as the forward and inverse solving models, respectively. The generalized Gaussian Markov random field model (GGMRF is treated as the regularization, and finally the influence of the measurement errors and initial distributions is investigated. Through the test cases, the MAP estimate algorithm is demonstrated to greatly improve the reconstruction results of the optical coefficients.

  3. Nonlinear kinetic modeling and simulations of Raman scattering in a two-dimensional geometry

    Directory of Open Access Journals (Sweden)

    Bénisti Didier

    2013-11-01

    Full Text Available In this paper, we present our nonlinear kinetic modeling of stimulated Raman scattering (SRS by the means of envelope equations, whose coefficients have been derived using a mixture of perturbative and adiabatic calculations. First examples of the numerical resolution of these envelope equations in a two-dimensional homogeneous plasma are given, and the results are compared against those of particle-in-cell (PIC simulations. These preliminary comparisons are encouraging since our envelope code provides threshold intensities consistent with those of PIC simulations while requiring computational resources reduced by 4 to 5 orders of magnitude compared to full-kinetic codes.

  4. Design of C-2W Thomson Scattering System

    Science.gov (United States)

    Zhai, Kan; Schindler, Tania; Zhang, Helen; Walters, Kurt; Thompson, Matthew; TAE Team

    2016-10-01

    A suite of multi-point Thomson scattering systems is now being designed and built in parallel with the construction of the C-2W FRC experimental device, which is expected to have a wide range of electron temperature Te and density ne from edge to center region at different operational phases. The suite consists of two sub-systems that measure Te and ne profiles at the C-2W central plane and at the jet region. A high-repetition rate Nd:YAG laser is planned for the central plane subsystem for time-resolved profile measurement at 1 kHz. The central plane and jet region subsystems have their own specially-designed collection optics that image 16 and 5 radial points along the laser-beam path onto corresponding surfaces of fiber bundles, which will then relay the collected laser light into dispersing polychromators. The polychromators are designed with five spectral channels with four channels optimized and dedicated to Te measurement and one channel dedicated to Rayleigh scattering calibration for ne measurement. Detail system design and layout of lasers, beam transportation and stray light control, collection optics and fiber optics, dispersion and detection system and its spectral calibration setup will be presented.

  5. Retrieving the size of particles with rough and complex surfaces from two-dimensional scattering patterns

    Science.gov (United States)

    Ulanowski, Z.; Hirst, E.; Kaye, P. H.; Greenaway, R.

    2012-12-01

    Scattered intensity measurement is a commonly used method for determining the size of small particles. However, it requires calibration and is subject to errors due to changes in incident irradiance or detector sensitivity. Analysis of two-dimensional scattering patterns offers an alternative approach. We test morphological image processing operations on patterns from a diverse range of particles with rough surfaces and/or complex structure, including mineral dust, spores, pollen, ice analogs and sphere clusters from 4 to 88 μm in size. It is found that the median surface area of intensity peaks is the most robust measure, and it is inversely proportional to particle size. The trend holds well for most particle types, as long as substantial roughness or complexity is present. One important application of this technique is the sizing of atmospheric particles, such as ice crystals.

  6. The Two-dimensional ElectromagneticScattering from Periodic Chiral Structures and Its Finite Element Approximation

    Institute of Scientific and Technical Information of China (English)

    张德悦; 马富明

    2004-01-01

    In this paper, we consider the electromagnetic scattering from periodic chiral structures. The structure is periodic in one direction and invariant in another direction. The electromagnetic fields in the chiral medium are governed by the Maxwell equations together with the Drude-Born-Fedorov equations. We simplify the problem to a two-dimensional scattering problem and we show that for all but possibly a discrete set of wave numbers, there is a unique quasi-periodic weak solution to the diffraction problem. The diffraction problem can be solved by finite element method. We also establish uniform error estimates for the finite element method and the error estimates when the truncation of the nonlocal transparent boundary operators takes place.

  7. |m| Partial wave treatment for two-dimensional Coulomb-scattering and Regge pole

    Institute of Scientific and Technical Information of China (English)

    WANG; Jing; ZENG; Jinyan

    2004-01-01

    The symmetry and |m| partial-wave analysis for two-dimensional (2D) Coulomb-scattering is investigated. As a function of energy E, the |m| partial-wave scattering amplitude f|m|(θ) is analytically continuated to the negative E (complex k) plane, and it is found that the bound state energy eigenvalues (E<0) are just located at the poles of f|m|(θ) on the positive imaginary k axis as is expected. In addition, as a function of |m|, f|m|(θ) is analytically continuated to the complex |m| plane, the bound state energy eigenvalues are just located at the poles of f|m|(θ) on the positive real |m| axis.

  8. 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...

  9. Status of the JET LIDAR Thomson Scattering diagnostic

    CERN Document Server

    Maslov, M; Kempenaars, M; Flanagan, J; contributors, JET EFDA

    2013-01-01

    The LIDAR Thomson scattering concept was proposed in 1983 and then implemented for the first time on the JET tokamak in 1987. A number of modifications were performed and published in 1995, but since then no major changes were made for almost 15 years. In 2010 a refurbishment of the diagnostic was started, with as main goals to improve its performance and to test the potential of new detectors which are considered as candidates for ITER. During the subsequent years a wide range of activities was performed aimed at increasing the diagnostic's light throughput, improvement of signal to noise ratio and amendment of the calibration procedures. Previously used MA-2 detectors were replaced by fast GaAsP detectors with much higher average QE. After all the changes were implemented, a significant improvement of the measured data was achieved. Statistical errors of measured temperature and density were reduced by a factor of 2 or more, depending on plasma conditions, and comfortably surpassed the values requested for ...

  10. Focussing effects in laser-electron Thomson scattering

    CERN Document Server

    Harvey, C; Holkundkar, A R

    2016-01-01

    We study the effects of laser pulse focussing on the spectral properties of Thomson scattered radiation. Modelling the laser as a paraxial beam we find that, in all but the most extreme cases of focussing, the temporal envelope has a much bigger effect on the spectrum than the focussing itself. For the case of ultra-short pulses where the paraxial model is no longer valid, we adopt a sub-cycle vector beam description of the field. It is found that the emission harmonics are blue shifted and broaden out in frequency space as the pulse becomes shorter. Additionally the carrier envelope phase becomes important, resulting in an angular asymmetry in the spectrum. We then use the same model to study the effects of focussing beyond the limit where the paraxial expansion is valid. It is found that fields focussed to sub-wavelength spot sizes produce spectra that are qualitatively similar to those from sub-cycle pulses due to the shortening of the pulse with focussing. Finally, we study high-intensity fields and find ...

  11. Chevron beam dump for ITER edge Thomson scattering system.

    Science.gov (United States)

    Yatsuka, E; Hatae, T; Vayakis, G; Bassan, M; Itami, K

    2013-10-01

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

  12. Thomson scattering at Pilot-PSI and Magnum-PSI

    Science.gov (United States)

    van Rooij, G. J.; van der Meiden, H. J.; 't Hoen, M. H. J.; Koppers, W. R.; Shumack, A. E.; Vijvers, W. A. J.; Westerhout, J.; Wright, G. M.; Rapp, J.

    2009-12-01

    A robust and sensitive Thomson scattering (TS) system has been developed for the high density low temperature plasma in the linear plasma generator Pilot-PSI, which routinely and reproducibly measures electron density and temperature profiles along a detection chord of 25 mm with a spatial resolution of 0.6 mm. The capabilities of the system are illustrated in this paper by a selection of new results from the research program at Pilot-PSI. TS data are presented that demonstrate the present plasma density record in Pilot-PSI: 5 × 1021 m-3 at a temperature of 3 eV. TS measurements in front of the target are combined with ion saturation current data to determine plasma velocities of 4-5 km s-1, which shows that heat convection is dominating over conduction. Single shot operation of TS is also possible, which is demonstrated by measurements revealing a rotating filamentary return current channel to the source anode. Finally, the TS system upgrade that will provide real time feedback of electron density and temperature in the larger plasma generator Magnum-PSI is discussed.

  13. Two-wavelength LIDAR Thomson scattering for ITER core plasma

    Science.gov (United States)

    Nielsen, P.; Gowers, C.; Salzmann, H.

    2017-07-01

    Our proposal for a LIDAR Thomson scattering system to measure Te and ne profiles in the ITER core plasma, is based on experience with the LIDAR system on JET, which is still operational after 30 years. The design uses currently available technology and complies with the measurement requirements given by ITER. In addition, it offers the following advantages over the conventional imaging approach currently being adopted by ITER: 1) No gas fill of the vessel required for absolute calibration. 2) Easier alignment. 3) Measurements over almost the complete plasma diameter. 4) Two mirrors only as front optics. For a given laser wavelength the dynamic range of the Te measurements is mainly limited by the collection optics' transmission roll-off in the blue and the range of spectral sensitivity of the required fast photomultipliers. With the originally proposed Ti:Sapphire laser, measurements of the envisaged maximum temperature of 40 keV are marginally possible. Here we present encouraging simulation results on the use of other laser systems and on the use of two lasers with different wavelength. Alternating two wavelengths was proposed already in 1997 as a method for calibrating the transmission of the collection system. In the present analysis, the two laser pulses are injected simultaneously. We find that the use of Nd:YAG lasers operated at fundamental and second harmonic, respectively, yields excellent results and preserves the spectral recalibration feature.

  14. Chevron beam dump for ITER edge Thomson scattering system

    Science.gov (United States)

    Yatsuka, E.; Hatae, T.; Vayakis, G.; Bassan, M.; Itami, K.

    2013-10-01

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

  15. Resonant scattering and mode coupling in two-dimensional textured planar waveguides.

    Science.gov (United States)

    Cowan, A R; Paddon, P; Pacradouni, V; Young, J F

    2001-05-01

    A heuristic formalism is developed for efficiently determining the specular reflectivity spectrum of two-dimensionally textured planar waveguides. The formalism is based on a Green's function approach wherein the electric fields are assumed to vary little over the thickness of the textured part of the waveguide. Its accuracy, when the thickness of the textured region is much smaller than the wavelength of relevant radiation, is verified by comparison with a much less efficient, exact finite difference solution of Maxwell's equations. In addition to its numerical efficiency, the formalism provides an intuitive explanation of Fano-like features evident in the specular reflectivity spectrum when the incident radiation is phase matched to excite leaky electromagnetic modes attached to the waveguide. By associating various Fourier components of the scattered field with bare slab modes, the dispersion, unique polarization properties, and lifetimes of these Fano-like features are explained in terms of photonic eigenmodes that reveal the renormalization of the slab modes due to interaction with the two-dimensional grating. An application of the formalism, in the analysis of polarization-insensitive notch filters, is also discussed.

  16. The upgraded Collective Thomson Scattering diagnostics of FTU

    Energy Technology Data Exchange (ETDEWEB)

    Bin, W., E-mail: wbin@ifp.cnr.it [Istituto di Fisica del Plasma – CNR, Milano (Italy); Bruschi, A. [Istituto di Fisica del Plasma – CNR, Milano (Italy); D’Arcangelo, O. [ENEA Unità Tecnica Fusione, C.R. Frascati, Frascati, Roma (Italy); Grosso, G. [Istituto di Fisica del Plasma – CNR, Milano (Italy); Lubiako, L. [Institute of Applied Physics – RAS, Nizhny Novgorod (Russian Federation); Tartari, U.; Figini, L.; Garavaglia, S. [Istituto di Fisica del Plasma – CNR, Milano (Italy); Grossetti, G. [Institute for Applied Materials – KIT, Karlsruhe (Germany); Moro, A. [Istituto di Fisica del Plasma – CNR, Milano (Italy); Orsitto, F.; Centioli, C. [ENEA Unità Tecnica Fusione, C.R. Frascati, Frascati, Roma (Italy); Galperti, C.; Granucci, G.; Mellera, V.; Minelli, D.; Nardone, A.; Simonetto, A. [Istituto di Fisica del Plasma – CNR, Milano (Italy); Vellucci, M. [ENEA Unità Tecnica Fusione, C.R. Frascati, Frascati, Roma (Italy)

    2015-10-15

    Highlights: • The new 140 GHz CTS diagnostics recently installed on the FTU device is presented. • The CTS transmission line is described in detail. • The potential of the new CTS configuration is shown with the aid of simulations. • The radiometric and data acquisition systems are described. • The new code TCSC is described for the first time. - Abstract: The 140 GHz Collective Thomson Scattering (CTS) diagnostics installed on the Frascati Tokamak Upgrade (FTU) has been upgraded. The new system now is ready both to detect the thermal CTS radiation (for the first time with the probe frequency below the 1st harmonic electron cyclotron resonance) and to study the impact of possible parametric decay instability (PDI) processes on the received signals. The EC front-steering antenna and transmission system have been complemented with a receiving line that matches a quasi-optical line feeding the homodyne multi-channel radiometer. The scattering volume can be placed in a wide range of locations by means of fast poloidal and toroidal rotations of the two plasma-facing mirrors that have an up–down symmetry with respect to the equatorial plane of the torus. The data acquisition system has been improved adding a new digitizer, with a bandwidth of 5 GHz and a maximum sampling rate of 12.5 GS/s. The possibility of directly sampling and Fourier transforming the down-converted signals greatly improves the suitability of the new diagnostics to carry out thermal ion temperature measurements and to study the competing PDI processes whenever present.

  17. 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...

  18. Cooperative resonances in light scattering from two-dimensional atomic arrays

    CERN Document Server

    Shahmoon, Ephraim; Lukin, Mikhail D; Yelin, Susanne F

    2016-01-01

    We consider light scattering off a two-dimensional (2D) dipolar array and show how it can be tailored by properly choosing the lattice constant of the order of the incident wavelength. In particular, we demonstrate that such arrays can operate as nearly perfect mirrors for a wide range of incident angles and frequencies close to the individual atomic resonance. These results can be understood in terms of the cooperative resonances of the surface modes supported by the 2D array. Experimental realizations are discussed, using ultracold arrays of trapped atoms and excitons in 2D semiconductor materials, as well as potential applications ranging from atomically thin metasurfaces to single photon nonlinear optics and nanomechanics.

  19. 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...

  20. Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Jacobsen, Asger Schou

    2014-01-01

    Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations...

  1. 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...

  2. The spectrometer of the High-Resolution Multi position Thomson Scattering Diagnostic for TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Herranz, J.; Barth, C.J.; Castejon, F.; Lopez-Sanchez, A.; Mirones, E.; Pastor, I.; Perez, D.; Rodriguez, C.

    2001-07-01

    Since 1998, a high-resolution multiposition thompson scattering system is in operation at the stellarator TJ-II, combining high accuracy and excellent spatial resolution. A description of the diagnostic spectrometer is presented. The main characteristics of the spectrometer that allow YJ-II Thomson scattering diagnostic to have high spatial and spectral resolution are described in this paper. (Author)

  3. Non-Maxwellian Electron Velocity Distributions Observed with Thomson Scattering in the Tortur Tokamak

    NARCIS (Netherlands)

    van Lammeren, A. C. A. P.; Barth, C. J.; Vanest, Q. C.; Schüller, F. C.

    1992-01-01

    The Thomson scattering spectrum represents the projection of the three-dimensional electron velocity distribution on the scattering vector. From this the local electron temperature and density can be derived. To determine the three-dimensional electron velocity distribution it is necessary to have s

  4. Two-dimensional molybdenum tungsten diselenide alloys: photoluminescence, Raman scattering, and electrical transport.

    Science.gov (United States)

    Zhang, Mei; Wu, Juanxia; Zhu, Yiming; Dumcenco, Dumitru O; Hong, Jinhua; Mao, Nannan; Deng, Shibin; Chen, Yanfeng; Yang, Yanlian; Jin, Chuanhong; Chaki, Sunil H; Huang, Ying-Sheng; Zhang, Jin; Xie, Liming

    2014-07-22

    Two-dimensional transition-metal dichalcogenide alloys have attracted intense attention due to their tunable band gaps. In the present work, photoluminescence, Raman scattering, and electrical transport properties of monolayer and few-layer molybdenum tungsten diselenide alloys (Mo1-xWxSe2, 0 ≤ x ≤ 1) are systematically investigated. The strong photoluminescence emissions from Mo1-xWxSe2 monolayers indicate composition-tunable direct band gaps (from 1.56 to 1.65 eV), while weak and broad emissions from the bilayers indicate indirect band gaps. The first-order Raman modes are assigned by polarized Raman spectroscopy. Second-order Raman modes are assigned according to its frequencies. As composition changes in Mo1-xWxSe2 monolayers and few layers, the out-of-plane A1g mode showed one-mode behavior, while B2g(1) (only observed in few layers), in-plane E2g(1), and all observed second-order Raman modes showed two-mode behaviors. Electrical transport measurement revealed n-type semiconducting transport behavior with a high on/off ratio (>10(5)) for Mo1-xWxSe2 monolayers.

  5. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Farias, G., E-mail: gonzalo.farias@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Dormido-Canto, S., E-mail: sebas@dia.uned.es [Departamento de Informática y Automática, UNED, 28040 Madrid (Spain); Vega, J., E-mail: jesus.vega@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Santos, M., E-mail: msantos@ucm.es [Departamento de Arquitectura de Computadores y Automática, Universidad Complutense de Madrid, 28040 Madrid (Spain); Pastor, I., E-mail: ignacio.pastor@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Fingerhuth, S., E-mail: sebastian.fingerhuth@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Ascencio, J., E-mail: j_ascencio21@hotmail.com [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile)

    2014-05-15

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process.

  6. Advanced Thomson scattering system for high-flux linear plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Meiden, H. J. van der; Lof, A. R.; Berg, M. A. van den; Brons, S.; Eck, H. J. N. van; Koelman, P. M. J.; Koppers, W. R.; Kruijt, O. G.; Oyevaar, T.; Prins, P. R.; Rapp, J.; Scholten, J.; Smeets, P. H. M.; Star, G. van der; Zeijlmans van Emmichoven, P. A. [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Donne, A. J. H.; Schram, D. C. [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, Eindhoven (Netherlands); Naumenko, N. N. [IPh NASB, Minsk (Belarus); Tugarinov, S. N. [SRC TRINITI, Troitsk, Moscow Reg. (Russian Federation)

    2012-12-15

    An advanced Thomson scattering system has been built for a linear plasma generator for plasma surface interaction studies. The Thomson scattering system is based on a Nd:YAG laser operating at the second harmonic and a detection branch featuring a high etendue (f /3) transmission grating spectrometer equipped with an intensified charged coupled device camera. The system is able to measure electron density (n{sub e}) and temperature (T{sub e}) profiles close to the output of the plasma source and, at a distance of 1.25 m, just in front of a target. The detection system enables to measure 50 spatial channels of about 2 mm each, along a laser chord of 95 mm. By summing a total of 30 laser pulses (0.6 J, 10 Hz), an observational error of 3% in n{sub e} and 6% in T{sub e} (at n{sub e}= 9.4 Multiplication-Sign 10{sup 18} m{sup -3}) can be obtained. Single pulse Thomson scattering measurements can be performed with the same accuracy for n{sub e} > 2.8 Multiplication-Sign 10{sup 20} m{sup -3}. The minimum measurable density and temperature are n{sub e} < 1 Multiplication-Sign 10{sup 17} m{sup -3} and T{sub e} < 0.07 eV, respectively. In addition, using the Rayleigh peak, superimposed on the Thomson scattered spectrum, the neutral density (n{sub 0}) of the plasma can be measured with an accuracy of 25% (at n{sub 0}= 1 Multiplication-Sign 10{sup 20} m{sup -3}). In this report, the performance of the Thomson scattering system will be shown along with unprecedented accurate Thomson-Rayleigh scattering measurements on a low-temperature argon plasma expansion into a low-pressure background.

  7. Dosimetric Characteristics of a Two-Dimensional Diode Array Detector Irradiated with Passively Scattered Proton Beams

    Energy Technology Data Exchange (ETDEWEB)

    Liengsawangwong, Praimakorn; Sahoo, Nanayan; Ding, Xiaoning; Lii, MingFwu; Gillin, Michale T.; Zhu, Xiaorong Ronald, E-mail: xrzhu@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States)

    2015-07-30

    Purpose: To evaluate the dosimetric characteristics of a two-dimensional (2D) diode array detector irradiated with passively scattered proton beams. Materials and Methods: A diode array detector, MapCHECK (Model 1175, Sun Nuclear, Melbourne, FL, USA) was characterized in passive-scattered proton beams. The relative sensitivity of the diodes and absolute dose calibration were determined using a 250 MeV beam. The pristine Bragg curves (PBCs) measured by MapCHECK diodes were compared with those of an ion chamber using a range shift method. The water-equivalent thickness (WET) of the diode array detector’s intrinsic buildup also was determined. The inverse square dependence, linearity, and other proton dosimetric quantities measured by MapCHECK were also compared with those of the ion chambers. The change in the absolute dose response of the MapCHECK as a function of accumulated radiation dose was used as an indicator of radiation damage to the diodes. 2D dose distribution with and without the compensator were measured and compared with the treatment planning system (TPS) calculations. Results: The WET of the MapCHECK diode’s buildup was determined to be 1.7 cm. The MapCHECK-measured PBC were virtually identical to those measured by a parallel-plate ion chamber for 160, 180, and 250 MeV proton beams. The inverse square results of the MapCHECK were within ±0.4% of the ion chamber results. The linearity of MapCHECK results was within 1% of those from the ion chamber as measured in the range between 10 and 300 MU. All other dosimetric quantities were within 1.3% of the ion chamber results. The 2D dose distributions for non-clinical fields without compensator and the patient treatment fields with the compensator were consistent with the TPS results. The absolute dose response of the MapCHECK was changed by 7.4% after an accumulated dose increased by 170 Gy. Conclusions: The MapCHECK is a convenient and useful tool for 2D dose distribution measurements using passively

  8. Simulated performance of the optical Thomson scattering diagnostic designed for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J. S., E-mail: ross36@llnl.gov; Datte, P.; Divol, L.; Galbraith, J.; Hatch, B.; Landen, O.; Manuel, A. M.; Molander, W.; Moody, J. D.; Swadling, G. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Froula, D. H.; Katz, J. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Kilkenny, J. [General Atomics, San Diego, California 92186 (United States); Montgomery, D. S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Weaver, J. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2016-11-15

    An optical Thomson scattering diagnostic has been designed for the National Ignition Facility to characterize under-dense plasmas. We report on the design of the system and the expected performance for different target configurations. The diagnostic is designed to spatially and temporally resolve the Thomson scattered light from laser driven targets. The diagnostic will collect scattered light from a 50 × 50 × 200 μm volume. The optical design allows operation with different probe laser wavelengths. A deep-UV probe beam (λ{sub 0} = 210 nm) will be used to Thomson scatter from electron plasma densities of ∼5 × 10{sup 20} cm{sup −3} while a 3ω probe will be used for plasma densities of ∼1 × 10{sup 19} cm{sup −3}. The diagnostic package contains two spectrometers: the first to resolve Thomson scattering from ion acoustic wave fluctuations and the second to resolve scattering from electron plasma wave fluctuations. Expected signal levels relative to background will be presented for typical target configurations (hohlraums and a planar foil).

  9. A high spatial resolution double-pulse Thomson scattering diagnostic; description, assessment of accuracy and examples of applications

    NARCIS (Netherlands)

    Beurskens, M. N. A.; Barth, C. J.; Cardozo, N. J. L.; van der Meiden, H. J.

    1999-01-01

    A high spatial resolution (3 mm full width half maximum, i.e. 2% of the minor radius) double-pulse multiposition Thomson scattering system was in operation at the Rijnhuizen tokamak project RTP from March 1996 until September 1998. It upgrades the previously installed single-pulse Thomson scattering

  10. Comparison of finite difference and finite element methods for simulating two-dimensional scattering of elastic waves

    NARCIS (Netherlands)

    Frehner, Marcel; Schmalholz, Stefan M.; Saenger, Erik H.; Steeb, Holger

    2008-01-01

    Two-dimensional scattering of elastic waves in a medium containing a circular heterogeneity is investigated with an analytical solution and numerical wave propagation simulations. Different combinations of finite difference methods (FDM) and finite element methods (FEM) are used to numerically solve

  11. Comparison of finite difference and finite element methods for simulating two-dimensional scattering of elastic waves

    NARCIS (Netherlands)

    Frehner, Marcel; Schmalholz, Stefan M.; Saenger, Erik H.; Steeb, Holger Karl

    2008-01-01

    Two-dimensional scattering of elastic waves in a medium containing a circular heterogeneity is investigated with an analytical solution and numerical wave propagation simulations. Different combinations of finite difference methods (FDM) and finite element methods (FEM) are used to numerically solve

  12. First results from the Thomson scattering diagnostic on Proto-MPEX

    Energy Technology Data Exchange (ETDEWEB)

    Biewer, Theodore M [ORNL; Meitner, Steven J [ORNL; Rapp, Juergen [ORNL

    2016-01-01

    A Thomson scattering diagnostic has been successfully implemented on the prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory. The diagnostic collects the light scattered by plasma electrons and spectroscopically resolves the Doppler shift imparted to the light by the velocity of the electrons. The spread in velocities is proportional to the electron temperature, while the total number of photons is proportional to the electron density. Thomson scattering is a technique used on many devices to measure the electron temperature (Te) and electron density (ne) of the plasma. A challenging aspect of the technique is to discriminate the small number of Thomson scattered photons against the large peak of background photons from the high-power laser used to probe the plasma. A variety of methods are used to mitigate the background photons in Proto-MPEX, including Brewster angled windows, viewing dumps, and light baffles. With these methods, first results were measured from Argon plasmas in Proto-MPEX, indicating Te ~ 2 eV and ne ~ 1x1019 m-3. The configuration of the Proto-MPEX Thomson scattering diagnostic will be described and plans for improvement will be given.

  13. Improvement in data processing of Thomson scattering diagnostic on HL-2A tokamak

    Science.gov (United States)

    Liu, C. H.; Wang, Y. Q.; Feng, Z.; Huang, Y.

    2015-12-01

    There are two types of digitizers to acquire the values of Thomson scattering signals in HL-2A tokamak. One is charge-sensitive analogue-to-digital converters (Q-ADCs) which simply integrates the signal over a gate interval, and the other is transient recorders with 12 bits resolution and 1 GHz sampling rate at each channel. Because the Thomson scattering diagnostic is prone to electrical noisy environment, in which Q-switched Nd:YAG lasers and polychromators are located closely to the HL-2A device, the high speed transient digitizers are found helpful to reduce noise overlapped in Thomson scattering signals. After triggered by the front of TTL pulse generated by laser light, data acquisition is fulfilled from -250 ns to 250 ns, so that the temporal evolution of Thomson scattering signals is obtained. A Gaussian function is utilized to fit the pulse shape of the digitized scattering signal by nonlinear least square methods. By pulse fitting and data processing, the influence of background perturbations is substantially reduced.

  14. Double-confocal resonator for X-ray generation via intracavity Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Xie, M. [Lawrence Berkeley Lab., CA (United States)

    1995-12-31

    There has been a growing interest in developing compact X-ray sources through Thomson scattering of a laser beam by a relativistic electron beam. For higher X-ray flux it is desirable to have the scattering to occur inside an optical resonator where the laser power is higher. In this paper I propose a double-confocal resonator design optimized for head-on Thomson scattering inside an FEL oscillator and analyze its performance taking into account the diffraction and FEL gain. A double confocal resonator is equivalent to two confocal resonators in series. Such a resonator has several advantages: it couples electron beam through and X-ray out of the cavity with holes on cavity mirrors, thus allowing the system to be compact; it supports the FEL mode with minimal diffraction loss through the holes; it provides a laser focus in the forward direction for a better mode overlap with the electron beam; and it provides a focus at the same location in the backward direction for higher Thomson scattering efficiency; in addition, the mode size at the focal point and hence the Rayleigh range can be adjusted simply through intracavity apertures; furthermore, it gives a large mode size at the mirrors to reduce power loading. Simulations as well as analytical results will be presented. Also other configurations of intracavity Thomson scattering where the double-confocal resonator could be useful will be discussed.

  15. Two-dimensional resonant magnetic soft X-ray scattering set-up for extreme sample environment.

    Science.gov (United States)

    Stanescu, Stefan; Mocuta, Cristian; Merlet, Frederic; Barbier, Antoine

    2013-01-01

    The newly built MagSAXS (magnetic small-angle X-ray scattering) set-up dedicated to the direct two-dimensional measurement of magnetic scattering using polarized synchrotron radiation in extreme sample environments is presented. Pure optical transport of the image is used to record the magnetic scattering with a two-dimensional CCD visible-light camera. The set-up is able to probe magnetic correlation lengths from the micrometer down to the nanometer scale. A detailed layout is presented along with preliminary results obtained at several beamlines at Synchrotron SOLEIL. The presented examples underline the wide range of possible applications spanning from correlation lengths determination to Fourier transform holography.

  16. 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...

  17. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD

    DEFF Research Database (Denmark)

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

    2010-01-01

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power ECRH system in LHD. The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH...

  18. Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited)

    DEFF Research Database (Denmark)

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

    2008-01-01

    The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110...

  19. Temporally resolved plasma composition measurements by collective Thomson scattering in TEXTOR

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Korsholm, Søren Bang; Nielsen, Stefan Kragh

    2012-01-01

    Fusion plasma composition measurements by collective Thomson scattering (CTS) were demonstrated in recent proof-of-principle measurements in TEXTOR [S. B. Korsholm et al., Phys. Rev. Lett. 106, 165004 (2011)]. Such measurements rely on the ability to resolve and interpret ion cyclotron structure...

  20. Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Furtula, Vedran; Salewski, Mirko; Leipold, Frank

    2012-01-01

    Here we present the design of the fast-ion collective Thomson scattering receiver for millimeter wave radiation installed at ASDEX Upgrade, a tokamak for fusion plasma experiments. The receiver can detect spectral power densities of a few eV against the electron cyclotron emission background...

  1. The prospect for fuel ion ratio measurements in ITER by collective Thomson scattering

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Korsholm, Søren Bang; Nielsen, Stefan Kragh

    2012-01-01

    We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT/nD, in ITER. Fuel ion ratio measurements will be important for plasma control and machine protection in ITER. Measurements of ion cyclotron structures...

  2. Recent development of collective Thomson scattering for magnetically confined fusion plasmas

    Science.gov (United States)

    Nielsen, S. K.; Michelsen, P. K.; Hansen, S. K.; Korsholm, S. B.; Leipold, F.; Rasmussen, J.; Salewski, M.; Schubert, M.; Stejner, M.; Stober, J.; Wagner, D.; The ASDEX Upgrade Team

    2017-02-01

    Here we review recent experimental developments within the field of collective Thomson scattering with a focus on the progress made on the devices TEXTOR and ASDEX Upgrade. We discuss recently discovered possibilities and limitations of the diagnostic technique. Diagnostic applications with respect to ion measurements are demonstrated. Examples include measurements of the ion temperature, energetic ion distribution function, and the ion composition.

  3. Recent development of collective Thomson scattering for magnetically confined fusion plasmas

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Michelsen, Poul; Hansen, S.K.;

    2017-01-01

    Here we review recent experimental developments within the field of collective Thomson scattering with a focus on the progress made on the devices TEXTOR and ASDEX Upgrade. We discuss recently discovered possibilities and limitations of the diagnostic technique. Diagnostic applications with respect...

  4. Collective Thomson scattering system for determination of ion properties in a high flux plasma beam

    NARCIS (Netherlands)

    van der Meiden, H. J.; Vernimmen, J. W. M.; Bystrov, K.; Jesko, K.; Kantor, M. Y.; De Temmerman, G.; Morgan, T. W.

    2016-01-01

    A collective Thomson scattering system has been developed for measuring ion temperature, plasma velocity and impurity concentration in the high density magnetized Magnum-PSI plasma beam, allowing for measurements at low temperature (<5 eV) and high electron density >4 × 1020 m−3, while

  5. 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...

  6. 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

  7. Measurements of Intrinsic Ion Bernstein Waves in a Tokamak by Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Korsholm, Søren Bang; Stejner Pedersen, Morten; Bindslev, Henrik;

    2011-01-01

    In this Letter we report measurements of collective Thomson scattering (CTS) spectra with clear signatures of ion Bernstein waves and ion cyclotron motion in tokamak plasmas. The measured spectra are in accordance with theoretical predictions and show clear sensitivity to variation in the density...

  8. Investigations of laser-induced plasma in argon by Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Mendys, A., E-mail: agata.mendys@uj.edu.pl [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Dzierzega, K.; Grabiec, M. [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Pellerin, S. [GREMI - site de Bourges, Universite d' Orleans, CNRS, rue Gaston Berger BP 4043, 18028 Bourges (France); Pokrzywka, B. [Obserwatorium Astronomiczne na Suhorze, Uniwersytet Pedagogiczny, ulica Podchorazych 2, 30-084 Krakow (Poland); Travaille, G.; Bousquet, B. [Centre de Physique Moleculaire Optique et Hertzienne, Universite Bordeaux 1, 351 Cours de la Liberation, 33405 Talence CEDEX (France)

    2011-09-15

    The Thomson scattering method was applied to quantify the electron number density and temperature of a laser spark formed in argon. The laser spark was generated by focusing a 15 mJ beam from the second harmonic ({lambda}{sub L} = 532 nm) of a nanosecond Nd:YAG laser with an 80 mm focal length lens. Images of the spark emission were obtained for times between 1 ns and 20 {mu}s after the laser pulse in order to characterize its spatial evolution. The electron density and temperature for the core of the plasma plume at different instants of its evolution were determined from the Thomson scattered spectra of another nanosecond Nd:YAG laser (532 nm, 10 to 60 mJ/pulse). In the time interval between 400 ns and 10 {mu}s between the laser induced plasma and Thomson scattering probe pulses, we found n{sub e} and T{sub e} to decrease from 4.3 Multiplication-Sign 10{sup 23} m{sup -3} to 2.4 Multiplication-Sign 10{sup 22} m{sup -3} and from 50 700 K to 11 100 K, respectively. Special care was paid to the plasma disturbance by the probe laser pulse in Thomson scattering experiments due to absorption of laser photons by electrons through the inverse bremsstrahlung process.

  9. 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...

  10. Preliminary project of s Thomson scattering system for the ETE tokamak; Projeto preliminar de um sistema de espalhamento Thomson para o Tokamak ETE

    Energy Technology Data Exchange (ETDEWEB)

    Berni, Luiz Angelo

    1997-12-31

    This report presents the preliminary project of the injection and laser light block system for the Thomson (ET) scattering diagnostic to be implanted at the ETE spheric tokamak of the Instituto Nacional de Pesquisas Espaciais (INPE/LAP). Also, a scanning system for the optics of scattered light 4 refs., 26 figs.

  11. Soft X-Ray Thomson Scattering in Warm Dense Hydrogen at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Faustlin, R R; Toleikis, S; Bornath, T; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gode, S; Gregori, G; Irsig, R; Laarmann, T; Lee, H J; Li, B; Meiwes-Broer, K; Mithen, J; Przystawik, A; Redlin, H; Redmer, R; Reinholz, H; Ropke, G; Tavella, F; Thiele, R; Tiggesbaumker, J; Uschmann, I; Zastrau, U; Tschentscher, T

    2009-07-15

    We present collective Thomson scattering with soft x-ray free electron laser radiation as a method to track the evolution of warm dense matter plasmas with {approx}200 fs time resolution. In a pump-probe scheme an 800 nm laser heats a 20 {micro}m hydrogen droplet to the plasma state. After a variable time delay in the order of ps the plasma is probed by an x-ray ultra violet (XUV) pulse which scatters from the target and is recorded spectrally. Alternatively, in a self-Thomson scattering experiment, a single XUV pulse heats the target while a portion of its photons are being scattered probing the target. From such inelastic x-ray scattering spectra free electron temperature and density can be inferred giving insight on relaxation time scales in plasmas as well as the equation of state. We prove the feasibility of this method in the XUV range utilizing the free electron laser facility in Hamburg, FLASH. We recorded Thomson scattering spectra for hydrogen plasma, both in the self-scattering and in the pump-probe mode using optical laser heating.

  12. Stray light analysis for the Thomson scattering diagnostic of the ETE Tokamak

    Science.gov (United States)

    Berni, L. A.; Albuquerque, B. F. C.

    2010-12-01

    Thomson scattering is a well-established diagnostic for measuring local electron temperature and density in fusion plasma, but this technique is particularly difficult to implement due to stray light that can easily mask the scattered signal from plasma. To mitigate this problem in the multipoint Thomson scattering system implemented at the ETE (Experimento Tokamak Esférico) a detailed stray light analysis was performed. The diagnostic system was simulated in ZEMAX software and scattering profiles of the mechanical parts were measured in the laboratory in order to have near realistic results. From simulation, it was possible to identify the main points that contribute to the stray signals and changes in the dump were implemented reducing the stray light signals up to 60 times.

  13. Stray light analysis for the Thomson scattering diagnostic of the ETE Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Berni, L. A. [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), 12.227-010 Sao Jose dos Campos, SP (Brazil); Albuquerque, B. F. C. [Instituto Nacional de Pesquisas Espaciais (INPE), Engenharia e Tecnologia Espaciais, Divisao de Eletronica Aeroespacial, 12.227-010 Sao Jose dos Campos, SP (Brazil)

    2010-12-15

    Thomson scattering is a well-established diagnostic for measuring local electron temperature and density in fusion plasma, but this technique is particularly difficult to implement due to stray light that can easily mask the scattered signal from plasma. To mitigate this problem in the multipoint Thomson scattering system implemented at the ETE (Experimento Tokamak Esferico) a detailed stray light analysis was performed. The diagnostic system was simulated in ZEMAX software and scattering profiles of the mechanical parts were measured in the laboratory in order to have near realistic results. From simulation, it was possible to identify the main points that contribute to the stray signals and changes in the dump were implemented reducing the stray light signals up to 60 times.

  14. Control and automation of the Pegasus multi-point Thomson scattering system.

    Science.gov (United States)

    Bodner, G M; Bongard, M W; Fonck, R J; Reusch, J A; Rodriguez Sanchez, C; Schlossberg, D J

    2016-11-01

    A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. Additionally, the system has been upgraded with a set of fast (∼1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

  15. Tokamak Plasmas : Electron temperature $(T_{e})$ measurements by Thomson scattering system

    Indian Academy of Sciences (India)

    R Rajesh; B Ramesh Kumar; S K Varshney; Manoj Kumar; Chhaya Chavda; Aruna Thakkar; N C Patel; Ajai Kumar; Aditya Team

    2000-11-01

    Thomson scattering technique based on high power laser has already proved its superoirity in measuring the electron temperature (e) and density (e) in fusion plasma devices like tokamaks. The method is a direct and unambiguous one, widely used for the localised and simultaneous measurements of the above parameters. In Thomson scattering experiment, the light scattered by the plasma electrons is used for the measurements. The plasma electron temperature is measured from the Doppler shifted scattered spectrum and density from the total scattered intensity. A single point Thomson scattering system involving a -switched ruby laser and PMTs as the detector is deployed in ADITYA tokamak to give the plasma electron parameters. The system is capable of providing the parameters e from 30 eV to 1 keV and e from 5 × 1012 cm-3-5× 1013 cm-3. The system is also able to give the parameter profile from the plasma center ( = 0 cm) to a vertical position of = +22 cm to = -14 cm, with a spatial resolution of 1 cm on shot to shot basis. This paper discusses the initial measurements of the plasma temperature from ADITYA.

  16. Spectral characterization of Compact Toroidal Hybrid plasmas in preparation for Thomson scattering measurements

    Science.gov (United States)

    Goforth, M. M.; Loch, S. D.; Maurer, D. A.; Pearce, A. J.; Traverso, P. J.

    2014-10-01

    A Thomson scattering system is in development for the Compact Toroidal Hybrid (CTH) experiment to provide localized, internal electron temperature and density measurements. Thomson scattering yields accurate information on the internal plasma electron pressure profile, which will aid in the equilibrium reconstruction of CTH plasmas using the V3FIT code. The expected Thomson scattered signal is approximately 1015 times less than the incident laser light, and can be overwhelmed by stray laser light, background plasma emission, and intrinsic detector noise. Background plasma emission measurements in the visible spectral region near the planned laser wavelength of 532 nm are underway using a Holospec f/1.8 spectrometer and an And or iStar image intensified CCD camera to quantify line and continuum background levels. In addition, impurity line identification and plans for a separate line-of-sight averaged impurity temperature and density measurement capability employing the Thomson spectrometer are in progress. This work is supported by US DOE Grant DE-FG-02-00ER54610 and by the Auburn University Undergraduate Research Fellowship.

  17. Spin-Dependent Scattering Effects and Dimensional Crossover in a Quasi-Two-Dimensional Disordered Electron System

    Institute of Scientific and Technical Information of China (English)

    YANG YongHong; WANG YongGang; LIU Mei; WANG Jin

    2002-01-01

    Two kinds of spin-depcndcnt scattering effects (magnetic-iinpurity and spin-orbit scatterings) axe investi-gated theoretically in a quasi-two-dimensional (quasi-2D) disordered electron system. By making use of the diagrammatictechniques in perturbation theory, we have calculated the dc conductivity and magnetoresistance due to weak-localizationeffects, the analytical expressions of them are obtained as functions of the interlayer hopping energy and the charac-teristic times: elastic, inelastic, magnetic and spin-orbit scattering times. The relevant dimensional crossover behaviorfrom 3D to 2D with decreasing the interlayer coupling is discussed, and the condition for the crossover is shown to bedependent on the aforementioned scattering times. At low temperature there exists a spin-dcpendent-scattering-induccddimensional crossover in this system.

  18. A high-power spatial filter for Thomson scattering stray light reduction

    Science.gov (United States)

    Levesque, J. P.; Litzner, K. D.; Mauel, M. E.; Maurer, D. A.; Navratil, G. A.; Pedersen, T. S.

    2011-03-01

    The Thomson scattering diagnostic on the High Beta Tokamak-Extended Pulse (HBT-EP) is routinely used to measure electron temperature and density during plasma discharges. Avalanche photodiodes in a five-channel interference filter polychromator measure scattered light from a 6 ns, 800 mJ, 1064 nm Nd:YAG laser pulse. A low cost, high-power spatial filter was designed, tested, and added to the laser beamline in order to reduce stray laser light to levels which are acceptable for accurate Rayleigh calibration. A detailed analysis of the spatial filter design and performance is given. The spatial filter can be easily implemented in an existing Thomson scattering system without the need to disturb the vacuum chamber or significantly change the beamline. Although apertures in the spatial filter suffer substantial damage from the focused beam, with proper design they can last long enough to permit absolute calibration.

  19. Scattering of strong electromagnetic wave by relativistic electrons: Thomson and Compton regimes

    Science.gov (United States)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.

    2017-04-01

    The processes of the nonlinear Compton and the nonlinear Thomson scattering in a field of intense plane electromagnetic wave in terms of photon yield have been considered. The quantum consideration of the Compton scattering process allows us to calculate the probability of a few successive collisions k of an electron with laser photons accompanied by the absorption of n photons (nonlinear regime) when the number of collisions and the number of absorbed photons are of random quantities. The photon spectrum of the nonlinear Thomson scattering process was obtained from the classical formula for intensity using the Planck's law. The conditions for which the difference between the classical and the quantum regimes is manifested was obtained. Such a condition is determined by a discrete quantum radiation mechanism, namely, by the mean number of photons k bar emitted by an electron passing through the laser pulse.

  20. Coherent and incoherent Thomson scattering on an argon/hydrogen microwave plasma torch with transient behaviour

    Science.gov (United States)

    Obrusník, A.; Synek, P.; Hübner, S.; van der Mullen, J. J. A. M.; Zajíčková, L.; Nijdam, S.

    2016-10-01

    A new method of processing time-integrated coherent Thomson scattering spectra is presented, which provides not only the electron density and temperature but also information about the transient behaviour of the plasma. Therefore, it is an alternative to single-shot Thomson scattering measurements as long as the scattering is coherent. The method is applied to a microwave plasma torch operating in argon or a mixture of argon with hydrogen at atmospheric pressure. Electron densities up to 8\\cdot {{10}21} m-3 (ionization degree above 10-3) were observed, which is more than two times higher than presented in earlier works on comparable discharges. Additionally, a parametric study with respect to the argon/hydrogen ratio and the input power was carried out and the results are discussed together with earlier Stark broadening measurements on the same plasma.

  1. Implementation of a high throughput spectrograph for Thomson scattering measurements on the Compact Toriodal Hybrid

    Science.gov (United States)

    Goforth, Matthew; Traverso, Peter; Maurer, David

    2013-10-01

    To better understand the equilibrium and stability of Compact Toroidal Hybrid (CTH) plasmas, a multipoint Thomson scattering system is under development at Auburn University. Thomson scattering will be performed at 532 nm using a frequency doubled Continuum PL DLS Nd:YAG laser. The Thomson scattered light will be measured using a high throughput HoloSpec f/1.8i imaging spectrograph with in-line interference filter for spectral discrimination of stray laser light. An image intensified charge coupled device (ICCD) camera employing a Gen III photocathode with quantum efficiency of approximately 50% near the frequency doubled laser line is planned as the detection element for the scattered light. Bench and CTH impurity line emission measurements will be presented quantifying spectrometer and ICCD performance and suitability for scattering measurements over the visible spectral region near 532 nm. This work has been supported by US Department of Energy Grant No. DE-FG02-00ER54610 and the Auburn University Undergraduate Research Fellowship Program.

  2. A HSS Matrix-Inspired Butterfly-Based Direct Solver for Analyzing Scattering from Two-dimensional Objects

    CERN Document Server

    Liu, Yang; Michielssen, Eric

    2016-01-01

    A butterfly-based fast direct integral equation solver for analyzing high-frequency scattering from two-dimensional objects is presented. The solver leverages a randomized butterfly scheme to compress blocks corresponding to near- and far-field interactions in the discretized forward and inverse electric field integral operators. The observed memory requirements and computational cost of the proposed solver scale as O(Nlog^2N) and O(N^1.5 logN), respectively. The solver is applied to the analysis of scattering from electrically large objects spanning over ten thousand of wavelengths and modeled in terms of five million unknowns.

  3. Dielectric effects on Thomson scattering in a relativistic magnetized plasma

    DEFF Research Database (Denmark)

    Bindslev, H.

    1991-01-01

    the absorption is small. Symmetry between variables relating to incident and scattered fields is demonstrated and shown to be in agreement with the reciprocity relation. Earlier results are confirmed in the cold plasma limit. Significant relativistic effects, of practical importance to the scattering......The effects of the dielectric properties of a relativistic magnetized plasma on the scattering of electromagnetic radiation by fluctuations in electron density are investigated. The origin of the density fluctuations is not considered. Expressions for the scattering cross-section and the scattered...... power accepted by the receiving antenna are derived for a plasma with spatial dispersion. The resulting expressions allow thermal motion to be included in the description of the plasma and remain valid for frequencies of the probing radiation in the region of omega(p) and omega(ce), provided...

  4. Electron kinetic effects on interferometry, polarimetry and Thomson scattering measurements in burning plasmas (invited).

    Science.gov (United States)

    Mirnov, V V; Brower, D L; Den Hartog, D J; Ding, W X; Duff, J; Parke, E

    2014-11-01

    At anticipated high electron temperatures in ITER, the effects of electron thermal motion on Thomson scattering (TS), toroidal interferometer/polarimeter (TIP), and poloidal polarimeter (PoPola) diagnostics will be significant and must be accurately treated. The precision of the previous lowest order linear in τ = Te/mec(2) model may be insufficient; we present a more precise model with τ(2)-order corrections to satisfy the high accuracy required for ITER TIP and PoPola diagnostics. The linear model is extended from Maxwellian to a more general class of anisotropic electron distributions that allows us to take into account distortions caused by equilibrium current, ECRH, and RF current drive effects. The classical problem of the degree of polarization of incoherent Thomson scattered radiation is solved analytically exactly without any approximations for the full range of incident polarizations, scattering angles, and electron thermal motion from non-relativistic to ultra-relativistic. The results are discussed in the context of the possible use of the polarization properties of Thomson scattered light as a method of Te measurement relevant to ITER operational scenarios.

  5. Electron kinetic effects on interferometry, polarimetry and Thomson scattering measurements in burning plasmas (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Mirnov, V. V.; Hartog, D. J. Den; Duff, J.; Parke, E. [Physics Department, University of Wisconsin - Madison and the Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, Madison, Wisconsin 53706 (United States); Brower, D. L.; Ding, W. X. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2014-11-15

    At anticipated high electron temperatures in ITER, the effects of electron thermal motion on Thomson scattering (TS), toroidal interferometer/polarimeter (TIP), and poloidal polarimeter (PoPola) diagnostics will be significant and must be accurately treated. The precision of the previous lowest order linear in τ = T{sub e}/m{sub e}c{sup 2} model may be insufficient; we present a more precise model with τ{sup 2}-order corrections to satisfy the high accuracy required for ITER TIP and PoPola diagnostics. The linear model is extended from Maxwellian to a more general class of anisotropic electron distributions that allows us to take into account distortions caused by equilibrium current, ECRH, and RF current drive effects. The classical problem of the degree of polarization of incoherent Thomson scattered radiation is solved analytically exactly without any approximations for the full range of incident polarizations, scattering angles, and electron thermal motion from non-relativistic to ultra-relativistic. The results are discussed in the context of the possible use of the polarization properties of Thomson scattered light as a method of T{sub e} measurement relevant to ITER operational scenarios.

  6. Polarimetric Scattering from Two-Dimensional Dielectric Rough Sea Surface with a Ship-Induced Kelvin Wake

    Directory of Open Access Journals (Sweden)

    Pengju Yang

    2016-01-01

    Full Text Available Based on the polarimetric scattering model of second-order small-slope approximation (SSA-II with tapered wave incidence for reducing the edge effect caused by limited surface size, monostatic and bistatic polarimetric scattering signatures of two-dimensional dielectric rough sea surface with a ship-induced Kelvin wake is investigated in detail by comparison with those of sea surface without ship wake. The emphasis of this paper is on an investigation of depolarized scattering and enhanced backscattering of sea surface with a ship wake that changes the sea surface geometric structure especially for low wind conditions. Numerical simulations show that in the plane of incidence rough sea surface scattering is dominated by copolarized scattering rather than cross-polarized scattering and that under low wind conditions a larger ship speed gives rise to stronger enhanced backscattering and enhanced depolarized scattering. For both monostatic and bistatic configuration, simulation results indicate that electromagnetic scattering signatures in the presence of a ship wake dramatically differ from those without ship wake, which may serve as a basis for the detection of ships in marine environment.

  7. Electron beam final focus system for Thomson scattering at ELBE

    Science.gov (United States)

    Krämer, J. M.; Budde, M.; Bødker, F.; Irman, A.; Jochmann, A.; Kristensen, J. P.; Lehnert, U.; Michel, P.; Schramm, U.

    2016-09-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and divergences of about 10 mrad using the FFS.

  8. Electron beam final focus system for Thomson scattering at ELBE

    Energy Technology Data Exchange (ETDEWEB)

    Krämer, J.M., E-mail: jmkr@danfysik.dk [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany); Budde, M.; Bødker, F. [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Irman, A.; Jochmann, A. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Kristensen, J.P. [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Lehnert, U.; Michel, P. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Schramm, U. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany)

    2016-09-11

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and divergences of about 10 mrad using the FFS.

  9. Electron beam final focus system for Thomson scattering at ELBE

    CERN Document Server

    Krämer, J.M.; Bødker, F.; Irman, A.; .Jochmann A.; Kristensen, J.P.; Lehnert U., HZDR; Michel, P.; Schrammb, U.; 10.1016/j.nima.2015.10.067

    2016-01-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and diverg...

  10. Electron Beam Final Focus System For Thomson Scattering At Elbe

    CERN Document Server

    Krämer, J.M.; Bødkera, F.; Irman, A.; Jochmann, A.; Kristensena, J.P.; Lehnert, U.; Michel, P.; Schramm, U.; 10.1016/j.nima.2015.10.067

    2016-01-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and diverg...

  11. A new dump system design for stray light reduction of Thomson scattering diagnostic system on EAST

    Science.gov (United States)

    Xiao, Shumei; Zang, Qing; Han, Xiaofeng; Wang, Tengfei; Yu, Jin; Zhao, Junyu

    2016-07-01

    Thomson scattering (TS) diagnostic is an important diagnostic for measuring electron temperature and density during plasma discharge. However, the measurement of Thomson scattering signal is disturbed by the stray light easily. The stray light sources in the Experimental Advanced Superconducting Tokamak (EAST) TS diagnostic system were analyzed by a simulation model of the diagnostic system, and simulation results show that the dump system is the primary stray light source. Based on the optics theory and the simulation analysis, a novel dump system including an improved beam trap was proposed and installed. The measurement results indicate that the new dump system can reduce more than 60% of the stray light for the diagnostic system, and the influence of stray light on the error of measured density decreases.

  12. Modular Python-based Code for Thomson Scattering System on NSTX-U

    Science.gov (United States)

    Horowitz, Benjamin; Diallo, Ahmed; Feibush, Eliot; Leblanc, Benoit

    2013-10-01

    Fast accurate and reliable measurements of electron temperature and density profiles within magnetically confined plasmas are essential for full operation of fusion devices. We detail the design and implementation of a modular Pythonbased code for the Thomson Scattering diagnostic system of NSTX-U which offers improvements in speed by making full use of the Python's architecture, open-source module packages, and ability to be parallelized across many processors. SciPy's weave package allows the implementation of C/C++ code within our program to clear up bottlenecks in data fitting while not loosing the flexibility and clarity of Python, while Numpy and MatplotLib allow calculations and plotting of the processed data. Using the standard MDSplus input, we create a flexible and expandable algorithm structure which can be implemented on any fusion device utilizing polychromator-based Thomson scattering diagnostic system. Supported by DOE SULI Fellowship at Princeton Plasma Physics Lab.

  13. Material Assessment for ITER’s Collective Thomson Scattering first mirror

    DEFF Research Database (Denmark)

    Santos, R.; Policarpo, H.; Gonçalves, B.

    2015-01-01

    ITER’s Collective Thomson Scattering (CTS) system is a diagnostic instrument that will measure the plasma density and velocity through Thomson scattering of microwave radiation. Some of the key components of the CTS are quasioptical mirrors used to produce astigmatic beam patterns, which have....... In this work, three different materials (molybdenum (Mo), stainless steel 316L (SS-316L) and tungsten (W)) are considered for the first mirror of the CTS. The objective is to assess the suitability of these materials for this mirror and to provide a first ranking, considering the neutron radiation loads...... Element Analysis (FEA) of the mirror over a 400s discharge (reasonable number for computational tests, since an ITER discharge will be between 200 s and 1000 s) , with and without mirror cooling, is performed. The results obtained in this preliminary analysis show that of the tested materials Mo and W...

  14. A new dump system design for stray light reduction of Thomson scattering diagnostic system on EAST.

    Science.gov (United States)

    Xiao, Shumei; Zang, Qing; Han, Xiaofeng; Wang, Tengfei; Yu, Jin; Zhao, Junyu

    2016-07-01

    Thomson scattering (TS) diagnostic is an important diagnostic for measuring electron temperature and density during plasma discharge. However, the measurement of Thomson scattering signal is disturbed by the stray light easily. The stray light sources in the Experimental Advanced Superconducting Tokamak (EAST) TS diagnostic system were analyzed by a simulation model of the diagnostic system, and simulation results show that the dump system is the primary stray light source. Based on the optics theory and the simulation analysis, a novel dump system including an improved beam trap was proposed and installed. The measurement results indicate that the new dump system can reduce more than 60% of the stray light for the diagnostic system, and the influence of stray light on the error of measured density decreases.

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

    DEFF Research Database (Denmark)

    Salewski, Mirko; Jacobsen, A.S.; Jensen, Thomas;

    2016-01-01

    We propose a diagnostic capable of measuring 2D fast-ion velocity distribution functions 푓2퐷푣 in the MeV-range in magnetized fusion plasmas. Today velocity-space tomography based on fast-ion D훼 spectroscopy is regularly used to measure 푓2퐷푣 for ion energies below 100 keV. Unfortunately, the signal......-tonoise ratio becomes fairly low for MeV-range ions. Ions at any energy can be detected well by collective Thomson scattering of mm-wave radiation from a high-power gyrotron. We demonstrate how collective Thomson scattering can be used to measure 푓2퐷푣 in the MeV-range in reactor relevant plasmas...

  16. 4{omega} Thomson scattering probe for high-density plasma characterization at Titan

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J. S.; Pollock, B. B. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Department of Mechanical and Aerospace Engineering, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093-0411 (United States); Kline, J. L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Yang, S.; Henesian, M.; Weiland, T.; Price, D.; Glenzer, S. H. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

    2010-10-15

    In preparation for the upcoming experiments on the Titan laser at the Jupiter Laser Facility, a new Thomson scattering system has been designed and implemented. This system allows electron temperature and density measurements in a high-density regime (n{sub e}>10{sup 21} cm{sup -3}). A 263 nm probe has been demonstrated to produce a total energy of 15 J at 4{omega}(263 nm) in a 1 ns square pulse with a focal spot size of 100 {mu}m. This probe has been used for imaging Thomson scattering of the ion feature. The goal of this study is to investigate the heating of a preformed plasma by a short-pulse heater beam.

  17. Two-dimensional time-dependent quantum-mechanical scattering event

    Energy Technology Data Exchange (ETDEWEB)

    Galbraith, I.; Ching, Y.S.; Abraham, E.

    1984-01-01

    Nonrelativistic quantum-mechanical scattering in two dimensions is studied numerically by integrating the time-dependent Schroedinger equation. A partial-wave analysis is used to discuss the numerical results. A potential barrier, a square well and a single slit are considered as the scattering potentials.

  18. Development of a YAG laser system for the edge Thomson scattering system in ITER.

    Science.gov (United States)

    Hatae, T; Yatsuka, E; Hayashi, T; Yoshida, H; Ono, T; Kusama, Y

    2012-10-01

    A prototype YAG laser system for the edge Thomson scattering system in ITER has been newly developed. Performance of the laser amplifier was improved by using flow tubes made of samarium-doped glass; the small signal gain reached 20 at its maximum. As a result, an output energy of 7.66 J at 100 Hz was successfully achieved, and the performance exceeded the target performance (5 J, 100 Hz).

  19. 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)

  20. Thomson scattering in the EXTRAP-T2 reversed-field pinch

    Energy Technology Data Exchange (ETDEWEB)

    Welander, A.

    1996-11-01

    A Thomson scattering system has been installed on the EXTRAP-T2 RFP experiment. The system measures the electron density and temperature in three radial points using three spectral channels. A description of the system, the calibration techniques and examples of data obtained are given. The error bars for the electron temperature measurements are estimated to be < 10% for typical T2-plasmas. 4 refs.

  1. Edge and core Thomson scattering systems and their calibration on the ASDEX Upgrade tokamak.

    Science.gov (United States)

    Kurzan, B; Murmann, H D

    2011-10-01

    A new 10 channel Thomson scattering (TS) system was installed on the ASDEX Upgrade tokamak to measure radial profiles of electron density and temperature at the plasma edge with high radial resolution. Together with the already existing TS system, which is now used for the core plasma, electron density and temperature profiles extending from the edge to the core are now obtained in a single discharge. The TS systems are relatively calibrated by an optical parametric oscillator.

  2. Edge and core Thomson scattering systems and their calibration on the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Kurzan, B.; Murmann, H. D. [Max-Planck Institut fuer Plasmaphysik, EURATOM Association Boltzmannstr.2, 85748 Garching (Germany)

    2011-10-15

    A new 10 channel Thomson scattering (TS) system was installed on the ASDEX Upgrade tokamak to measure radial profiles of electron density and temperature at the plasma edge with high radial resolution. Together with the already existing TS system, which is now used for the core plasma, electron density and temperature profiles extending from the edge to the core are now obtained in a single discharge. The TS systems are relatively calibrated by an optical parametric oscillator.

  3. Cell growth characteristics from angle- and polarization-resolved light scattering: Prospects for two-dimensional correlation analysis

    Science.gov (United States)

    Herran Cuspinera, Roxana M.; Hore, Dennis K.

    2016-11-01

    We highlight the potential of generalized two-dimensional correlation analysis for the fingerprinting of cell growth in solution monitored by light scattering, where the synchronous and asynchronous responses serve as a sensitive marker for the effect of growth conditions on the distribution of cell morphologies. The polarization of the scattered light varies according to the cell size distribution, and so the changes in the polarization over time are an excellent indicator of the dynamic growth conditions. However, direct comparison of the polarization-, time-, and angle-resolved signals between different experiments is hindered by the subtle changes in the data, and the inability to easily adapt models to account for these differences. Using Mie scattering simulations of different growth conditions, and some preliminary experimental data for a single set of conditions, we illustrate that correlation analysis provides rapid and sensitive qualitative markers of growth characteristics.

  4. The use of ultraviolet Thomson scattering as a versatile diagnostic for detailed measurements of a collisional laser produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tracy, M.D.

    1993-01-08

    Collective Thomson scattering from ion-acoustic waves at 266nm is used to obtain spatially resolved, two-dimensional electron density, sound speed, and radial drift profiles of a collisional laser plasma. An ultraviolet diagnostic wavelength minimizes the complicating effects of inverse bremsstrahlung and refractive turning in the coronal region of interest, where the electron densities approach n{sub c}/10. Laser plasmas of this type are important because they model some of the aspects of the plasmas found in high-gain laser-fusion pellets irradiated by long pulse widths where the laser light is absorbed mostly in the corona. The experimental results and LASNEX simulations agree within a percent standard deviation of 40% for the electron density and 50% for the sound speed and radial drift velocity. Thus it is shown that the hydrodynamics equations with classical coefficients and the numerical approximations in LASNEX are valid models of laser-heated, highly collisional plasmas. The versatility of Thomson scattering is expanded upon by extending existing theory with a Fokker-Planck based model to include plasmas that are characterized by (0 {le} k{sub ia}{lambda}{sub ii} {le} {infinity}) and ZT{sub e}/T{sub i}, where k{sub ia} is the ion- acoustic wave number, {lambda}{sub ii} is the ion-ion mean free path, Z is the ionization state of the plasma, and T{sub e}, T{sub i} are the electron and ion temperatures in electron volts respectively. The model is valid for plasmas in which the electrons are approximately collisionless, (k{sub ia}{lambda}{sub ei}, k{sub ia}{lambda}{sub ee} {ge} 1), and quasineutrality holds, ({alpha} {much_gt}1), where {alpha} = 1/k{lambda}{sub DE} and {lambda}{sub DE} is the electron Debye length. This newly developed model predicts the lineshape of the ion-acoustic Thomson spectra and when fit to experimental data provides a direct measurement of the relative thermal flow velocity between the electrons and ions.

  5. The preliminary design of the optical Thomson scattering diagnostic for the National Ignition Facility

    Science.gov (United States)

    Datte, P.; Ross, J. S.; Froula, D.; Galbraith, J.; Glenzer, S.; Hatch, B.; Kilkenny, J.; Landen, O.; Manuel, A. M.; Molander, W.; Montgomery, D.; Moody, J.; Swadling, G.; Weaver, J.; Vergel de Dios, G.; Vitalich, M.

    2016-05-01

    The National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion programs. We report on the preliminary design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community's understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beamsplitter and gratings before the shot. A deep-UV probe beam (λ0 between 185-215 nm) will optimally collect Thomson scattered light from plasma densities of 5 x 1020 electrons/cm3 while a 3ω probe will optimally collect Thomson scattered light from plasma densities of 1 x 1019 electrons/cm3. We report the phase I design of a two phase design strategy. Phase I includes the OTS recording system to measure background levels at NIF and phase II will include the integration of a probe laser.

  6. Bloch waves in an arbitrary two-dimensional lattice of subwavelength Dirichlet scatterers

    CERN Document Server

    Schnitzer, Ory

    2016-01-01

    We study waves governed by the planar Helmholtz equation, propagating in an infinite lattice of subwavelength Dirichlet scatterers, the periodicity being comparable to the wavelength. Applying the method of matched asymptotic expansions, the scatterers are effectively replaced by asymptotic point constraints. The resulting coarse-grained Bloch-wave dispersion problem is solved by a generalised Fourier series, whose singular asymptotics in the vicinities of scatterers yield the dispersion relation governing modes that are strongly perturbed from plane-wave solutions existing in the absence of the scatterers; there are also empty-lattice waves that are only weakly perturbed. Characterising the latter is useful in interpreting and potentially designing the dispersion diagrams of such lattices. The method presented, that simplifies and expands on Krynkin & McIver [Waves Random Complex, 19 347 2009], could be applied in the future to study more sophisticated designs entailing resonant subwavelength elements di...

  7. Bi-directional two-dimensional/three-dimensional convertible integral imaging using scattering polarizer

    Science.gov (United States)

    Yeom, Jiwoon; Hong, Jisoo; Park, Soon-gi; Min, Sung-Wook; Lee, Byoungho

    2012-10-01

    A bi-directional 2D/3D convertible integral imaging system is proposed. Two optical modules composed of a scattering polarizer and a linear polarizer are adopted, and 2D or 3D mode operation is easily changed by converting polarization states of the projected images. In the 2D mode, the incident light is scattered at the scattering polarizer and the scattered light facing the lens-array is blocked, a 2D image is observable only at the same side as the projector. In the 3D mode, the incident light with the transmission polarization is directly projected onto a lens-array, and the 3D images are integrated. Our proposed system is able to display the 3D images as well as the 2D images for the observers who are placed in front and rear side of the system.

  8. Riemann–Hilbert problem approach for two-dimensional flow inverse scattering

    Energy Technology Data Exchange (ETDEWEB)

    Agaltsov, A. D., E-mail: agalets@gmail.com [Faculty of Computational Mathematics and Cybernetics, Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Novikov, R. G., E-mail: novikov@cmap.polytechnique.fr [CNRS (UMR 7641), Centre de Mathématiques Appliquées, Ecole Polytechnique, 91128 Palaiseau (France); IEPT RAS, 117997 Moscow (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny (Russian Federation)

    2014-10-15

    We consider inverse scattering for the time-harmonic wave equation with first-order perturbation in two dimensions. This problem arises in particular in the acoustic tomography of moving fluid. We consider linearized and nonlinearized reconstruction algorithms for this problem of inverse scattering. Our nonlinearized reconstruction algorithm is based on the non-local Riemann–Hilbert problem approach. Comparisons with preceding results are given.

  9. Investigation of first mirror heating for the collective Thomson scattering diagnostic in ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Meo, Fernando; Bindslev, Henrik

    2008-01-01

    Collective Thomson scattering (CTS) has the capabilities to measure phase space densities of fast ion populations in ITER resolved in configuration space, in velocity space, and in time. In the CTS system proposed for ITER, probing radiation at 60 GHz generated by two 1 MW gyrotrons is scattered...... in the plasma and collected by arrays of receivers. The transmission lines from the gyrotrons to the plasma and from the plasma to the receivers contain several quasioptical mirrors among other components. These are designed to produce astigmatic beam patterns in the plasma where the beam shapes will have...

  10. 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...

  11. Investigation of first mirror heating for the collective Thomson scattering diagnostic in ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Meo, Fernando; Bindslev, Henrik;

    2008-01-01

    Collective Thomson scattering (CTS) has the capabilities to measure phase space densities of fast ion populations in ITER resolved in configuration space, in velocity space, and in time. In the CTS system proposed for ITER, probing radiation at 60 GHz generated by two 1 MW gyrotrons is scattered...... modeling of a first mirror on the high field side indicates that the mirror curvature may warp due to heating. This may alter the beam quality, and therefore, thermal effects have to be accounted for during the design of the mirror. The modeling further demonstrates that thin mirrors are superior to thick...

  12. LIGHT SOURCE: TW Laser system for Thomson scattering X-ray light source at Tsinghua University

    Science.gov (United States)

    Yan, Li-Xm; Du, Ying-Chao; Du, Qiang; Li, Ren-Kai; Hua, Jian-Fei; Huang, Wen-Hui; Tang, Chuan-Xiang

    2009-06-01

    A TW (Tera Watt) laser system based on Ti:sapphire mainly for the Tsinghua Thomson scattering X-ray light source (TTX) is being built. Both UV (ultraviolet) laser pulse for driving the photocathode radio-frequency (RF) gun and the IR (infrared) laser pulse as the electron-beam-scattered-light are provided by the system. Efforts have also been made in laser pulse shaping and laser beam transport to optimize the high-brightness electron beam production by the photocathode RF gun.

  13. CO2 laser collective Thomson scattering diagnostics on the HT-7 tokamak

    Institute of Scientific and Technical Information of China (English)

    李亚东; 李建刚; 毛剑珊

    2004-01-01

    A CW CO2 laser collective Thomson scattering diagnostics was developed to measure plasma density fluctuations on the HT-7 tokamak. The design and construction of CO2 laser scattering apparatus is described. The laser source is a continuous-wave CO2 laser with a cavity length of 1.9 m and a power output of about 10 W at 10.6 μm. The k-resolution of the system is △k ≈ 3.2 cm-1. The preliminary data from the diagnostic is presented.

  14. TW Laser system for Thomson scattering X-ray light source at Tsinghua University

    Institute of Scientific and Technical Information of China (English)

    YAN Li-Xin; DU Ying-Chao; DU Qiang; LI Ren-Kai; HUA Jian-Fei; HUANG Wen-Hui; TANG Chuan-Xiang

    2009-01-01

    A TW(Tera Watt)laser system based on Ti:sapphire mainly for the Tsinghua Thomson scattering X-ray light source(TTX)is being built.Both UV(ultraviolet)laser pulse for driving the photocathode radiofrequency(RF)gun and the IR(infrared)laser pulse as the electron-beam-scattered-light are provided by the system.Efforts have also been made in laser pulse shaping and laser beam transport to optimize the high-brightness electron beam production by the photocathode RF gun.

  15. When is high-dimensional scattering chaos essentially two dimensional? Measuring the product structure of singularities.

    Science.gov (United States)

    Drótos, G; Jung, C; Tél, T

    2012-11-01

    We demonstrate how the area of the enveloping surface of the scattering singularities in a three-degrees-of-freedom (3-dof) system depends on a perturbation parameter controlling the distance from a reducible case. This dependence is monotonic and approximately linear. Therefore it serves as a measure for this distance, which can be extracted from an investigation of the fractal structure. These features are a consequence of the dynamics being governed by normally hyperbolic invariant manifolds. We conclude that typical n-dof chaotic scattering exhibits either structures developing out of a stack of chaotic structures of 2-dof type or hardly any chaotic effects.

  16. Electron-electron scattering in linear transport in two-dimensional systems

    DEFF Research Database (Denmark)

    Hu, Ben Yu-Kuang; Flensberg, Karsten

    1996-01-01

    We describe a method for numerically incorporating electron-electron scattering in quantum wells for small deviations of the distribution function from equilibrium, within the framework of the Boltzmann equation. For a given temperature T and density n, a symmetric matrix needs to be evaluated only...... once, and henceforth it can be used to describe electron-electron scattering in any Boltzmann equation linear-response calculation for that particular T and n. Using this method, we calculate the distribution function and mobility for electrons in a quantum well, including full finite...

  17. Numerical studies of the scattering of light from a two-dimensional randomly rough interface between two dielectric media

    CERN Document Server

    Hetland, Øyvind S; Nordam, Tor; Simonsen, Ingve

    2016-01-01

    The scattering of polarized light incident from one dielectric medium on its two-dimensional randomly rough interface with a second dielectric medium is studied. A reduced Rayleigh equation for the scattering amplitudes is derived for the case where p- or s-polarized light is incident on this interface, with no assumptions being made regarding the dielectric functions of the media. Rigorous, purely numerical, nonperturbative solutions of this equation are obtained. They are used to calculate the reflectivity and reflectance of the interface, the mean differential reflection coefficient, and the full angular distribution of the intensity of the scattered light. These results are obtained for both the case where the medium of incidence is the optically less dense medium, and in the case where it is the optically more dense medium. Optical analogues of the Yoneda peaks observed in the scattering of x-rays from metal surfaces are present in the results obtained in the latter case. Brewster scattering angles for d...

  18. Implementation of the matrix sparse decomposition technique to the scattering of two-dimensional homogeneous dielectric cylinders

    Science.gov (United States)

    Liu, Y. W.; Song, Y. M.; Mei, K. K.

    2001-03-01

    In this paper, a novel matrix-thinning technique, matrix sparse decomposition (MSD) [Liu et al., 1998, 1999], has been implemented to solve the scattering of waves by two-dimensional (2-D) homogeneous dielectric cylinders for the first time. The MSD technique is a further development of the integral equation formulation of the measured equation of invariance (MEI) (IE-MEI) [Rius et al., 1996a; Hirose et al., 1999a]. The MSD describes the local relationship between total currents and scattered fields rather than that between the scattered electric fields and the scattered magnetic fields in the IE-MEI. The MSD directly thins a dense matrix from singular integral equations, such as method of moments (MOM), into two sparse matrices. The IE-MEI method has difficulty in solving thin wire or thin plate structure problems. However, the MSD can do it without a hitch. Numerical examples for the scattering of 2-D homogeneous dielectric circular and rectangular cylinders under both transverse magnetic and transverse electric plane wave incidences show that the MSD is a simple and effective technique to thin the MOM dense matrix.

  19. Three disks in a row a two-dimensional scattering analog of the double-well problem

    CERN Document Server

    Wirzba, A; Wirzba, Andreas; Rosenqvist, Per E

    1996-01-01

    We investigate the scattering off three non-overlapping disks equidistantly spaced along a line in the two-dimensional plane with the radii of the outer disks equal and the radius of the inner disk varied. This system is a two-dimensional scattering analog to the double-well-potential (bound state) problem in one dimension. In both systems the symmetry-splittings between symmetric and anti-symmetric states or resonances, respectively, have to be traced back to tunneling effects, as semiclassically the geometrical periodic orbits have no contact with the vertical symmetry axis. We construct the leading semiclassical ``creeping'' orbits which are responsible for the symmetry-splitting of the resonances in this system. The collinear three-disk-system is not only one of the simplest but also one of the most effective systems for detecting creeping phenomena. While in symmetrically placed n-disk systems creeping corrections affect the sub-leading resonances, they here alone determine the symmetry splitting of the ...

  20. Data Processing and Acquisition System for the HT-7 Multipulse Thomson Scattering Diagnostic

    Institute of Scientific and Technical Information of China (English)

    陈卓天; 赵君煜; 方自深; 李亚东; 杨利

    2003-01-01

    This article describes the data processing and acquisition system for the HT-7 mul-tipulse Thomson scattering diagnostic. An eight-pulse laser is used in the Thomson scatteringsystem to obtain electron temperature profiles at eight different times throughout an entire plasmadischarge. The major components of the diagnostic system consist of a multipulse Nd-glass laser,system. The data processing software along with LeCroy 2250L will perform the data acquisition.In order to simplify the operation and extend the capability of its compatibility with other mathsoftwares, the processing software has been improved by the authors. The new software based onthe VC++ easily utilizes some math softwares to calculate the electron temperature. The newsoftware is simpler and more operational than the old one.

  1. Two-dimensional position-sensitive detectors for small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    McElhaney, S.A.; Vandermolen, R.I.

    1990-05-01

    In this paper, various detectors available for small angle neutron scattering (SANS) are discussed, along with some current developments being actively pursued. A section has been included to outline the various methodologies of position encoding/decoding with discussions on trends and limitations. Computer software/hardware vary greatly from institute and experiment and only a general discussion is given to this area. 85 refs., 33 figs.

  2. Two Dimensional Acoustic Propagation Through Oceanic Internal Solitary Waves: Weak Scattering Theory and Numerical Simulation

    Science.gov (United States)

    2006-06-01

    sech2 wave form is used because the amplitude and horizontal displacement are solutions of the Korteweg de Vries ( KdV ) non linear wave equation which...a solution to the KDV wave equation . After making the frozen field approximation, the soliton can be represented by the following mathematical...scattering. 3. The Gaussian Soliton As discussed, the sech2 form of a soliton is chosen because it is an exact solution to the KDV wave equation . For

  3. Demonstration of X-ray Thomson Scattering on Shenguang-Ⅱ Laser Facility

    Institute of Scientific and Technical Information of China (English)

    胡广月; 张小丁; 郑坚; 雷安乐; 沈百飞; 徐至展; 张继彦; 杨家敏; 杨国洪; 韦敏习; 李军; 丁永坤

    2012-01-01

    X-ray Thomson scattering technique for diagnosing dense plasma was demonstrated on Shenguang-Ⅱ laser facility. Laser plasma x-ray source of titanium He-a lines (-4.75 keV), generated by laser beam (1.5 kJ/527 nm/2 ns) heated titanium thin foil, was used as x-ray probe beam. The x-ray probe was then scattered by cold CH foam column of 1 g/cm^3 density. The scattered radiation at 90° was diffracted by polyethylene terephthalate (PET) crystal and recorded on x-ray charge-coupled device. Well-defined scattering spectra were obtained with good signal to noise ratio.

  4. Thomson scattering from near-solid density plasmas using soft x-ray free electron lasers

    CERN Document Server

    Höll, A

    2006-01-01

    We propose a collective Thomson scattering experiment at the VUV free electron laser facility at DESY (FLASH) which aims to diagnose warm dense matter at near-solid density. The plasma region of interest marks the transition from an ideal plasma to a correlated and degenerate many-particle system and is of current interest, e.g. in ICF experiments or laboratory astrophysics. Plasma diagnostic of such plasmas is a longstanding issue. The collective electron plasma mode (plasmon) is revealed in a pump-probe scattering experiment using the high-brilliant radiation to probe the plasma. The distinctive scattering features allow to infer basic plasma properties. For plasmas in thermal equilibrium the electron density and temperature is determined from scattering off the plasmon mode.

  5. Thomson scattering from near-solid density plasmas using soft x-ray free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Holl, A; Bornath, T; Cao, L; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gregori, G; Laarmann, T; Meiwes-Broer, K H; Przystawik, A; Radcliffe, P; Redmer, R; Reinholz, H; Ropke, G; Thiele, R; Tiggesbaumker, J; Toleikis, S; Truong, N X; Tschentscher, T; Uschmann, I; Zastrau, U

    2006-11-21

    We propose a collective Thomson scattering experiment at the VUV free electron laser facility at DESY (FLASH) which aims to diagnose warm dense matter at near-solid density. The plasma region of interest marks the transition from an ideal plasma to a correlated and degenerate many-particle system and is of current interest, e.g. in ICF experiments or laboratory astrophysics. Plasma diagnostic of such plasmas is a longstanding issue. The collective electron plasma mode (plasmon) is revealed in a pump-probe scattering experiment using the high-brilliant radiation to probe the plasma. The distinctive scattering features allow to infer basic plasma properties. For plasmas in thermal equilibrium the electron density and temperature is determined from scattering off the plasmon mode.

  6. JT-60U Thomson scattering system with multiple ruby laser and high spatial resolution for high electron temperature plasma measurement

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Hidetoshi; Naito, Osamu; Yamashita, Osamu; Kitamura, Shigeru; Hatae, Takaki; Nagashima, Akira [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1996-11-01

    This article describes the design and operation of a 60 spatial channel Thomson scattering system as of 1996 with multiple ruby lasers to measure the electron temperature T{sub e} and density n{sub e} profiles of the JT-60U plasmas. The wide spectral range (403-683 nm) of the spectrometer and newly developed two-dimensional detector (high repetition photodiode array) has enabled this system to measure the high electron temperature plasma (5 keV or more) formed at the plasma core during negative magnetic shear discharge with high precision and reliability. The high spatial resolution (8 mm) have provided the precise measurement of steep electron temperature and density gradients formed at the plasma edge and in the scrape-off layer during H-mode discharge. The multilaser operation with the minimum time interval of 2 ms has provided an essential tool for the transient phenomenon measurement like the formation process of edge transport barrier during L- to H-mode transition and internal transport barrier during discharge with negative magnetic shear, the relaxation process of pellet injected plasma and so on. Measurement examples of recent JT-60U T{sub e} and n{sub e} profiles are also presented. (author)

  7. A Two-Dimensional Helmholtz Equation Solution for the Multiple Cavity Scattering Problem

    Science.gov (United States)

    2013-02-01

    present an efficient block Gauss– Seidel method , which may be written as follows: given ðuð0Þ1 ; ;u ð0Þ n Þ>, define ðuðkÞ1 ; . . . ;u ðkÞ n Þ>; k P...well-posed single cavity scattering problems (5.5)–(5.7) for the block Gauss– Seidel method at each iteration. 5.2. Transparent boundary condition... Seidel method for two consecutive approx- imations again the number of iterations for all three types of cavities. It can be seen from Fig. 10 that

  8. Thomson scattering analysis of large scale fluctuations in the ASDEX Upgrade edge

    Energy Technology Data Exchange (ETDEWEB)

    Kurzan, B; Horton, L D; Murmann, H; Neuhauser, J; Suttrop, W [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2007-06-15

    Large scale fluctuations in between edge localized modes (ELMs) are the main source for the scatter in plasma edge H mode profiles of electron density and temperature, as measured by high precision, high resolution Thomson scattering. These large scale fluctuations are also observed with electron cyclotron emission. They are quantitatively analysed by 2D poloidal snapshots of electron density and temperature, based on a 5 x 10 matrix of scattering volumes provided by the Thomson scattering system. Fluctuations with a quasi-periodic structure are found in a 2D snapshot with a frequency of about 61%. When interpreted as field-aligned helical structures toroidal quasi-mode numbers of 6-48 are found. The amplitudes of the fluctuations decrease with increasing quasi-mode number and edge profile gradient lengths. The amplitudes of the large scale structures in the steep gradient region are anti-correlated with the divertor D{sub {alpha}}-intensity. The particle loss during an ELM is at least to a significant fraction due to the electron density 'blobs' observed in the scrape-off layer. The large scale fluctuations also perturb the measurement of 1D radial profiles. In the middle of the steep gradient region the perturbations are symmetric, but asymmetric both further inside (more minima) and further outside (more maxima)

  9. Generation of Attosecond X-Ray Pulse through Coherent Relativistic Nonlinear Thomson Scattering

    CERN Document Server

    Lee, K; Jeong, Y U; Lee, B C; Park, S H

    2005-01-01

    In contrast to some recent experimental results, which state that the Nonlinear Thomson Scattered (NTS) radiation is incoherent, a coherent condition under which the scattered radiation of an incident laser pulse by a bunch of electrons can be coherently superposed has been investigated. The Coherent Relativistic Nonlinear Thomson Scattered (C-RNTS) radiation makes it possible utilizing the ultra-short pulse nature of NTS radiation with a bunch of electrons, such as plasma or electron beams. A numerical simulation shows that a 25 attosecond X-ray pulse can be generated by irradiating an ultra-intense laser pulse of 4x10(19) W/cm2 on an ultra-thin solid target of 50 nm thickness, which is commercially available. The coherent condition can be easily extended to an electron beam from accelerators. Different from the solid target, much narrower electron beam is required for the generation of an attosecond pulse. Instead, this condition could be applied for the generation of intense Compton scattered X-rays with a...

  10. Design and implementation of a Thomson scattering diagnostic for the Compact Toroidal Hybrid

    Science.gov (United States)

    Traverso, P. J.; Maurer, D. A.; Hartwell, G. J.; Knowlton, S. F.; Archmiller, M. C.; Goforth, M. M.

    2013-10-01

    The Compact Toroidal Hybrid (CTH) experiment is investigating the avoidance of disruptions in ohmically driven torsaton plasmas as the ratio of vacuum transform to the total transform is changed. To better characterize these plasmas under this wide range of magnetic configurations, a new Thomson scattering diagnostic is being implemented to measure electron temperature and density profiles. These important internal profile measurements will be incorporated into the V3FIT code to enable better 3D equilibrium reconstruction. The Thomson scattering system uses a frequency doubled Continuum PL DLS 2 J Nd:YaG laser. The incident beam is passed vertically through an entrance Brewster window and a baffle system to minimize stray laser light. The beam exits through another Brewster window to an external beam dump. Polarization optics are planned to maximize the scattered light directed to the collection system for the specific scattering geometry of CTH. This work is supported by the USDoE under grant DE-FG02-00ER54610.

  11. Effect of polarization roughness scattering (PRS) on two-dimensional electron transport of MgZnO/ZnO heterostructures

    Science.gov (United States)

    Wang, Ping; Guo, Lixin; Song, Zhenjie; Yang, Yintang; Shang, Tao; Li, Jing; Huang, Feng; Zheng, Qinghong

    2013-12-01

    Quantum transport properties of two-dimensional electron gas (2DEG) in undoped MgZnO/ZnO heterostructures with polarization charge effect have been investigated theoretically. Polarization roughness scattering (PRS) combining polarization charge and interface roughness scattering was proposed as a new scattering mechanism. It was found that the carriers confined in the heterostructures (HSs) would be scattered from polarization charges when they were moving along the in-plane and PRS played a very important role for the low-temperature electron mobility when the electron density Ns exceeded 1.0e11 cm-2, especially in a higher electron density region. With PRS, the experimental data on the density dependence of 2DEG mobility in the MgZnO/ZnO HSs under study can be well reproduced. The study indicates that the improved processing techniques providing a smooth interface and a good separation between the 2DEG electrons and the polarization charges should be significant for the quantum device’s performance.

  12. Polarization of x-gamma radiation produced by a Thomson and Compton inverse scattering

    Science.gov (United States)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Drebot, I.; Giribono, A.; Maroli, C.; Rossi, A. R.; Serafini, L.; Tomassini, P.; Vaccarezza, C.; Variola, A.

    2015-11-01

    A systematic study of the polarization of x-gamma rays produced in Thomson and Compton scattering is presented, in both classical and quantum schemes. Numerical results and analytical considerations let us to establish the polarization level as a function of acceptance, bandwidth and energy. Few sources have been considered: the SPARC_LAB Thomson device, as an example of a x-ray Thomson source, ELI-NP, operating in the gamma range. Then, the typical parameters of a beam produced by a plasma accelerator has been analyzed. In the first case, with bandwidths up to 10%, a contained reduction (<10 % ) in the average polarization occurs. In the last case, for the nominal ELI-NP relative bandwidth of 5 ×1 0-3 , the polarization is always close to 1. For applications requiring larger bandwidth, however, a degradation of the polarization up to 30% must be taken into account. In addition, an all optical gamma source based on a plasma accelerated electron beam cannot guarantee narrow bandwidth and high polarization operational conditions required in nuclear photonics experiments.

  13. Measurements of ion temperature and plasma hydrogenic composition by collective Thomson scattering in neutral beam heated discharges at TEXTOR

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Salewski, Mirko; Korsholm, Søren Bang

    2013-01-01

    A method is developed to perform plasma composition and ion temperature measurements across the plasma minor radius in TEXTOR based on ion cyclotron structures in collective Thomson scattering spectra. By gradually moving the scattering volume, we obtain measurements across the outer midplane...

  14. A parallelized Python based Multi-Point Thomson Scattering analysis in NSTX-U

    Science.gov (United States)

    Miller, Jared; Diallo, Ahmed; Leblanc, Benoit

    2014-10-01

    Multi-Point Thomson Scattering (MPTS) is a reliable and accurate method of finding the temperature, density, and pressure of a magnetically confined plasma. Nd:YAG (1064 nm) lasers are fired into the plasma with a frequency of 60 Hz, and the light is Doppler shifted by Thomson scattering. Polychromators on the midplane of the tokamak pick up the light at various radii/scattering angles, and the avalanche photodiode's voltages are added to an MDSplus tree for later analysis. This project ports and optimizes the prior serial IDL MPTS code into a well-documented Python package that runs in parallel. Since there are 30 polychromators in the current NSTX setup (12 more will be added when NSTX-U is completed), using parallelism offers vast savings in performance. NumPy and SciPy further accelerate numerical calculations and matrix operations, Matplotlib and PyQt make an intuitive GUI with plots of the output, and Multiprocessing parallelizes the computationally intensive calculations. The Python package was designed with portability and flexibility in mind so it can be adapted for use in any polychromator-based MPTS system.

  15. Classical Heat-Flux Measurements in Coronal Plasmas from Collective Thomson-Scattering Spectra

    Science.gov (United States)

    Henchen, R. J.; Hu, S. X.; Katz, J.; Froula, D. H.; Rozmus, W.

    2016-10-01

    Collective Thomson scattering was used to measure heat flux in coronal plasmas. The relative amplitude of the Thomson-scattered power into the up- and downshifted electron plasma wave features was used to determine the flux of electrons moving along the temperature gradient at three to four times the electron thermal velocity. Simultaneously, the ion-acoustic wave features were measured. Their relative amplitude was used to measure the flux of the return-current electrons. The frequencies of these ion-acoustic and electron plasma wave features provide local measurements of the electron temperature and density. These spectra were obtained at five locations along the temperature gradient in a laser-produced blowoff plasma. These measurements of plasma parameters are used to infer the Spitzer-Härm flux (qSH = - κ∇Te ) and are in good agreement with the values of the heat flux measured from the scattering-feature asymmetries. Additional experiments probed plasma waves perpendicular to the temperature gradient. The data show small effects resulting from heat flux compared to probing waves along the temperature gradient. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  16. Design and implementation of a Thomson scattering diagnostic for the Compact Toroidal Hybrid Experiment

    Science.gov (United States)

    Traverso, P. J.; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.; Goforth, M. M.; Loch, S. D.; Pearce, A. J.; Cianciosa, M. R.

    2014-10-01

    A Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The initial system takes a single point measurement and will be used to assess options for an upgrade to a multi-point system providing electron temperature and density profiles. This single point measurement will reduce the uncertainty in the reconstructed peak pressure by an order of magnitude for both ohmically driven, current-carrying plasmas and future gyrotron-heated stellarator plasmas. A principle design goal is to minimize stray laser light, geometrically on the machine side and spectrally on the collection side, to allow measurements of both full and half Thomson scattered spectral profiles. The beam, generated by a frequency doubled Continuum 2 J Nd:YaG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize stray light. Light collection, spectral processing, and signal detection are accomplished with an f / # ~ 1 aspheric lens, a Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. The estimated number of scattered photons per channel will be of the order of 5 ×103 with a signal to noise ratio of S / N = 19 This work is supported by U.S. Department of Energy Grant No. DE-FG02-00ER54610.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  18. Collective Thomson scattering for ion temperature and velocity measurements on Magnum-PSI: a feasibility study

    Science.gov (United States)

    van der Meiden, H. J.

    2010-04-01

    In this paper, collective Thomson scattering (CTS) is proposed for measuring the ion temperature and axial/rotational velocity of a plasma jet in the linear plasma generator Magnum-PSI, where ITER-relevant plasma conditions will be simulated. CTS is feasible at Magnum-PSI, because high electron densities (ne) can be obtained at low electron temperatures, which means that small Debye lengths are achievable. Calculations show that CTS is possible at the fundamental wavelength (1064 nm) of a Nd : YAG laser. At this wavelength, a scattering angle of 17-35° is sufficiently small to achieve a scattering parameter 1 1.5 × 1021 m-3. The design considerations of the CTS diagnostic are described in this paper.

  19. X-ray Thomson scattering measurements from hohlraum-driven spheres on the OMEGA laser

    Science.gov (United States)

    Saunders, A. M.; Jenei, A.; Döppner, T.; Falcone, R. W.; Kraus, D.; Kritcher, A.; Landen, O. L.; Nilsen, J.; Swift, D.

    2016-11-01

    X-ray Thomson scattering (XRTS) is a powerful diagnostic for probing warm and hot dense matter. We present the design and results of the first XRTS experiments with hohlraum-driven CH2 targets on the OMEGA laser facility at the Laboratory for Laser Energetics in Rochester, NY. X-rays seen directly from the XRTS x-ray source overshadow the elastic scattering signal from the target capsule but can be controlled in future experiments. From the inelastic scattering signal, an average plasma temperature is inferred that is in reasonable agreement with the temperatures predicted by simulations. Knowledge gained in this experiment shows a promising future for further XRTS measurements on indirectly driven OMEGA targets.

  20. Elevation angle alignment of quasi optical receiver mirrors of collective Thomson scattering diagnostic by sawtooth measurements

    DEFF Research Database (Denmark)

    Moseev, D.; Meo, Fernando; Korsholm, Søren Bang;

    2012-01-01

    Localized measurements of the fast ion velocity distribution function and the plasma composition measurements are of significant interest for the fusion community. Collective Thomson scattering (CTS) diagnostics allow such measurements with spatial and temporal resolution. Localized measurements...... require a good alignment of the optical path in the transmission line. Monitoring the alignment during the experiment greatly benefits the confidence in the CTS measurements. An in situ technique for the assessment of the elevation angle alignment of the receiver is developed. Using the CTS diagnostic...

  1. Time evolution analysis of the electron distribution in Thomson/Compton back-scattering

    Energy Technology Data Exchange (ETDEWEB)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Maroli, C.; Serafini, L.; Rossi, A. R. [INFN-Universitá degli Studi Milano, Via Celoria, 16 20133 Milano (Italy)

    2013-07-28

    We present the time evolution of the energy distribution of a relativistic electron beam after the Compton back-scattering with a counter-propagating laser field, performed in the framework of the Quantum Electrodynamics, by means of the code CAIN. As the correct angular distribution of the spontaneous emission is accounted, the main effect is the formation of few stripes, followed by the diffusion of the more energetic particles toward lower values in the longitudinal phase space. The Chapman-Kolmogorov master equation gives results in striking agreement with the numerical ones. An experiment on the Thomson source at SPARC-LAB is proposed.

  2. Time evolution analysis of the electron distribution in Thomson/Compton back-scattering

    Science.gov (United States)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Maroli, C.; Serafini, L.; Rossi, A. R.

    2013-07-01

    We present the time evolution of the energy distribution of a relativistic electron beam after the Compton back-scattering with a counter-propagating laser field, performed in the framework of the Quantum Electrodynamics, by means of the code CAIN. As the correct angular distribution of the spontaneous emission is accounted, the main effect is the formation of few stripes, followed by the diffusion of the more energetic particles toward lower values in the longitudinal phase space. The Chapman-Kolmogorov master equation gives results in striking agreement with the numerical ones. An experiment on the Thomson source at SPARC-LAB is proposed.

  3. Thomson scattering measurement of a shock in laser-produced counter-streaming plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Morita, T.; Kuramitsu, Y.; Moritaka, T. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Sakawa, Y.; Takabe, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Graduate School of Science, Osaka University, 1-1 Machikane-yama, Toyonaka, Osaka 560-0043 (Japan); Tomita, K.; Nakayama, K.; Inoue, K.; Uchino, K. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Ide, T.; Tsubouchi, K. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nishio, K.; Ide, H.; Kuwada, M. [Graduate School of Science, Osaka University, 1-1 Machikane-yama, Toyonaka, Osaka 560-0043 (Japan)

    2013-09-15

    We report the first direct measurement of temporally and spatially resolved plasma temperatures at a shock as well as its spatial structure and propagation in laser-produced counter-streaming plasmas. Two shocks are formed in counter-streaming collisionless plasmas early in time, and they propagate opposite directions. This indicates the existence of counter-streaming collisionless flows to keep exciting the shocks, even though the collisional effects increase later in time. The shock images are observed with optical diagnostics, and the upstream and downstream plasma parameters of one of the shocks are measured using Thomson scattering technique.

  4. Ultrashort hard x-ray pulses generated by 90 degrees Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Chin, A.H. [Univ. of California, Berkeley, CA (United States); Schoenlein, R.W.; Glover, T.E. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Ultrashort x-ray pulses permit observation of fast structural dynamics in a variety of condensed matter systems. The authors have generated 300 femtosecond, 30 keV x-ray pulses by 90 degrees Thomson scattering between femtosecond laser pulses and relativistic electrons. The x-ray and laser pulses are synchronized on a femtosecond time scale, an important prerequisite for ultrafast pump-probe spectroscopy. Analysis of the x-ray beam properties also allows for electron bunch characterization on a femtosecond time scale.

  5. A simulation study of Tsinghua Thomson scattering X-ray source

    Institute of Scientific and Technical Information of China (English)

    TANG Chuan-Xiang; LI Ren-Kai; HUANG Wen-Hui; CHEN Huai-Bi; DU Ying-Chao; DU Qiang; DU Tai-Bin; HE Xiao-Zhong; HUA Jian-Fei; LIN Yu-Zhen; QIAN Hou-Jun; SHI Jia-Ru; XIANG Dao; YAN Li-Xin; Yu Pei-Cheng

    2009-01-01

    Thomson scattering X-ray sources are compact and afrordable facifities that produce short duration,high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies,and also medical and industrial applications.Such a facility has been built at the Accelerator Laboratory of Tsinghua University,and upgrade is in progress.In this paper,we present a proposed layout of the upgrade with design parameters by simulation,aiming at high X-ray pulses flux and brightness,and also enabling advanced dynamics studies and applications of the electron beam.Design and construction status of main subsystems are also presented.

  6. Fast integrator based data acquisition system for the SST-1 Thomson scattering system

    Science.gov (United States)

    Patel, Kiran; Kumar, Ajai

    2010-04-01

    An operational transconductance amplifier based fast charge-integrating module (FCIM) is designed and developed for an easy acquisition of fast Thomson scattered and background signal. FCIM based data acquisition technique can be used for the measurement of charge pulses of <20 ns duration. The response of the module is tested using a standard pulsed charge-generating module. The measuring charge range of the module depends on the integrating capacitor. Comparison of the performance of FCIM to commercially available module shows that it has better dynamic range with higher sensitivity and less measurement error. The module is quite cost effective and has many new features.

  7. Fast integrator based data acquisition system for the SST-1 Thomson scattering system

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Kiran; Kumar, Ajai [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

    2010-04-15

    An operational transconductance amplifier based fast charge-integrating module (FCIM) is designed and developed for an easy acquisition of fast Thomson scattered and background signal. FCIM based data acquisition technique can be used for the measurement of charge pulses of <20 ns duration. The response of the module is tested using a standard pulsed charge-generating module. The measuring charge range of the module depends on the integrating capacitor. Comparison of the performance of FCIM to commercially available module shows that it has better dynamic range with higher sensitivity and less measurement error. The module is quite cost effective and has many new features.

  8. Design of collection optics and polychromators for a JT-60SA Thomson scattering system.

    Science.gov (United States)

    Tojo, H; Hatae, T; Sakuma, T; Hamano, T; Itami, K; Aida, Y; Suitoh, S; Fujie, D

    2010-10-01

    This paper presents designs of collection optics for a JT-60SA Thomson scattering system. By using tangential (to the toroidal direction) YAG laser injection, three collection optics without strong chromatic aberration generated by the wide viewing angle and small design volume were found to measure almost all the radial space. For edge plasma measurements, the authors optimized the channel number and wavelength ranges of band-pass filters in a polychromator to reduce the relative error in T(e) by considering all spatial channels and a double-pass laser system with different geometric parameters.

  9. LIGHT SOURCE: A simulation study of Tsinghua Thomson scattering X-ray source

    Science.gov (United States)

    Tang, Chuan-Xiang; Li, Ren-Kai; Huang, Wen-Hui; Chen, Huai-Bi; Du, Ying-Chao; Du, Qiang; Du, Tai-Bin; He, Xiao-Zhong; Hua, Jian-Fei; Lin, Yu-Zhen; Qian, Hou-Jun; Shi, Jia-Ru; Xiang, Dao; Yan, Li-Xin; Yu, Pei-Cheng

    2009-06-01

    Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.

  10. Fitting of the Thomson scattering density and temperature profiles on the COMPASS tokamak

    Science.gov (United States)

    Stefanikova, E.; Peterka, M.; Bohm, P.; Bilkova, P.; Aftanas, M.; Sos, M.; Urban, J.; Hron, M.; Panek, R.

    2016-11-01

    A new technique for fitting the full radial profiles of electron density and temperature obtained by the Thomson scattering diagnostic in H-mode discharges on the COMPASS tokamak is described. The technique combines the conventionally used modified hyperbolic tangent function for the edge transport barrier (pedestal) fitting and a modification of a Gaussian function for fitting the core plasma. Low number of parameters of this combined function and their straightforward interpretability and controllability provide a robust method for obtaining physically reasonable profile fits. Deconvolution with the diagnostic instrument function is applied on the profile fit, taking into account the dependence on the actual magnetic configuration.

  11. The Design of the Polychromator for Thomson Scattering Measurements on HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    杨利; 赵君煜; 方自深

    2004-01-01

    A five-channel polychromator, utilizing high performance interference filters, has been completed for Thomson scattering measurements on HT-7 tokamak. For our instrument, the range of electron temperature varies from 50 eV to 1.5 keV. According to this, the bandpass of the different interference filters are chosen. Unique features of the polychromator are high throughput,easy alignment, flexibility and compact size when compared with other alternatives. In this article,both the method of designing and the measured transmission curves for the polychromator are given.

  12. The effect of bound states on X-ray Thomson scattering for partially ionized plasmas

    OpenAIRE

    Nilsen, J.; Johnson, W.R.; Cheng, K. T.

    2012-01-01

    X-ray Thomson scattering is being developed as a method to measure the temperature, electron density, and ionization state of high energy density plasmas such as those used in inertial confinement fusion. X-ray laser sources have always been of interest because of the need to have a bright monochromatic x-ray source to overcome plasma emission and eliminate other lines in the background that complicate the analysis. With the advent of the xray free electron laser (X-FEL) at the SLAC Linac Coh...

  13. Impact of beam ions on α-particle measurements by collective Thomson scattering in ITER

    DEFF Research Database (Denmark)

    Egedal, J.; Bindslev, H.; Budny, R.V.

    2005-01-01

    Collective Thomson scattering (CTS) has been proposed as a viable diagnostic for characterizing fusion born a-distributions in ITER. However, the velocities of the planned 1 MeV deuterium heating beam ions in 1TER are similar to that of fusion born a-particles and may therefore mask...... the measurements of the fusion products. We apply a new technique for calculating the orbit averaged source, (S), of beam ions for various ITER scenarios. With the known (S) Fokker-Planck modelling is applied to characterize the beam ions during the slowing down process. Theoretical CTS signals for both beam ions...

  14. Signal processing of Thomson scattering data in a noisy environment in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Kurzan, B; Jakobi, M; Murmann, H [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2004-01-01

    For the Thomson scattering diagnostic in the ASDEX Upgrade tokamak, new transient recorders for acquiring the time evolution of the scattering pulses are used. Instead of integrating over the scattering pulse, as performed by the usually applied charge-sensitive analogue-to-digital converters (ADCs), a non-Gaussian pulse shape is fitted to the measured scattering signal. Both in this fitting procedure and in determination of the electron density and temperature from the scattering signals, correlated noise is taken into account. The number of outliers due to perturbations of the scattering signal is substantially reduced and the resulting electron density and temperature values are of higher accuracy than those that were obtained with the evaluation method based on charge-sensitive ADCs. The minimum electron density, detectable with a signal-to-noise ratio of 1, is now at n{sub e} = 0.75 x 10{sup 18} m{sup -3}, which is a factor of 3 lower than that obtained with the evaluation based on the integration over the scattering pulse.

  15. Development of laser beam injection system for the Edge Thomson Scattering (ETS) in ITER

    Science.gov (United States)

    Yatsuka, E.; Hatae, T.; Suitoh, S.; Ohara, M.; Hagita, K.; Inoue, K.; Bassan, M.; Walsh, M.; Itami, K.

    2016-01-01

    This paper focuses on the design and development of the laser injection system for the ITER Edge Thomson Scattering system (ETS). The ITER ETS achieves a temporal resolution of 100 Hz by firing two 50 Hz laser beams alternatively. The use of dual lasers enables us to perform the Thomson scattering measurements at a temporal resolution of 50 Hz in case that one of the laser systems stops functioning. A new type of beam combiner was developed to obtain a single beam that is collinear and fixed linearly polarized from two laser beams using a motor-driven rotating half-wave plate. The rotating half-wave plate method does not induce misalignment even if the rotating mechanism malfunctions. The combined beam is relayed from the diagnostic hall to the plasma using mirror optics and is absorbed at the beam dump integrated on the inner blanket. The beam alignment system was designed to direct the laser beam onto the center of the beam dump head. The beam position at the beam dump is monitored by four alignment laser beams which propagate parallel to the diagnostic Nd:YAG laser beam and imaging systems installed outside the diagnostic port.

  16. Detecting non-maxwellian electron velocity distributions at JET by high resolution Thomson scattering.

    Science.gov (United States)

    Beausang, K V; Prunty, S L; Scannell, R; Beurskens, M N; Walsh, M J; de la Luna, E

    2011-03-01

    The present work is motivated by a long standing discrepancy between the electron temperature measurements of Thomson scattering (TS) and electron cyclotron emission (ECE) diagnostics for plasmas with strong auxiliary heating observed at both JET and TFTR above 6–7 keV, where in some cases the ECE electron temperature measurements can be 15%–20% higher than the TS measurements. Recent analysis based on ECE results at JET has shown evidence of distortions to the Maxwellian electron velocity distribution and a correlation with the TS and ECE discrepancies has been suggested. In this paper, a technique to determine the presence of non-Maxwellian behavior using TS diagnostics is outlined. The difficulties and limitations of modern TS system designs to determine the electron velocity distribution are also discussed. It is demonstrated that small deviations such as those suggested by previous ECE analysis could be potentially detected, depending on the spectral layout of the TS polychromators. The spectral layout of the JET high resolution Thomson scattering system is such that it could be used to determine these deviations between 1 and 6 keV, and the results presented here indicate that no evidence of non-Maxwellian behavior is observed in this range. In this paper, a modification to the current polychromator design is proposed, allowing non-Maxwellian distortions to be detected up to at least 10 keV.

  17. Detecting non-Maxwellian electron velocity distributions at JET by high resolution Thomson scattering

    Science.gov (United States)

    Beausang, K. V.; Prunty, S. L.; Scannell, R.; Beurskens, M. N.; Walsh, M. J.; de La Luna, E.; Jet Efda Contributors

    2011-03-01

    The present work is motivated by a long standing discrepancy between the electron temperature measurements of Thomson scattering (TS) and electron cyclotron emission (ECE) diagnostics for plasmas with strong auxiliary heating observed at both JET and TFTR above 6-7 keV, where in some cases the ECE electron temperature measurements can be 15%-20% higher than the TS measurements. Recent analysis based on ECE results at JET has shown evidence of distortions to the Maxwellian electron velocity distribution and a correlation with the TS and ECE discrepancies has been suggested. In this paper, a technique to determine the presence of non-Maxwellian behavior using TS diagnostics is outlined. The difficulties and limitations of modern TS system designs to determine the electron velocity distribution are also discussed. It is demonstrated that small deviations such as those suggested by previous ECE analysis could be potentially detected, depending on the spectral layout of the TS polychromators. The spectral layout of the JET high resolution Thomson scattering system is such that it could be used to determine these deviations between 1 and 6 keV, and the results presented here indicate that no evidence of non-Maxwellian behavior is observed in this range. In this paper, a modification to the current polychromator design is proposed, allowing non-Maxwellian distortions to be detected up to at least 10 keV

  18. Conceptual Design Studies of the KSTAR Bay-Nm Cassette and Thomson Scattering Optics

    Energy Technology Data Exchange (ETDEWEB)

    Feder, R.; Ellis, R.; Johnson, D.; Park, H.; Lee, H. G.

    2005-09-26

    A Multi-Channel Thomson Scattering System viewing the edge and core of the KSTAR plasma will be installed at the mid-plane port Bay-N. An engineering design study was undertaken at PPPL in collaboration with the Korea Basic Science Institute (KBSI) to determine the optimal optics and cassette design. Design criteria included environmental, mechanical and optical factors. All of the optical design options have common design features; the Thomson Scattering laser, an in-vacuum shutter, a quartz heat shield and primary vacuum window, a set of optical elements and a fiber optic bundle. Neutron radiation damage was a major factor in the choice of competing lens-based and mirror-based optical designs. Both the mirror based design and the lens design are constrained by physical limits of the Bay-N cassette and interference with the Bay-N micro-wave launcher. The cassette will contain the optics and a rail system for maintenance of the optics.

  19. Computer data-acquisition and control system for Thomson-scattering measurements

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, K.A.; Foskett, R.D.; Kindsfather, R.R.; Lazarus, E.A.; Thomas, C.E.

    1983-03-01

    The Thomson-Scattering Diagnostic System (SCATPAK II) used to measure the electron temperature and density in the Impurity Study Experiment is interfaced to a Perkin-Elmer 8/32 computer that operates under the OS/32 operating system. The calibration, alignment, and operation of this diagnostic are all under computer control. Data acquired from 106 photomultiplier tubes installed on 15 spectrometers are transmitted to the computer by eighteen 12-channel, analog-to-digital integrators along a CAMAC serial highway. With each laser pulse, 212 channels of data are acquired: 106 channels of signal plus background and 106 channels of background only. Extensive use of CAMAC instrumentation enables large amounts of data to be acquired and control processes to be performed in a time-dependent environment. The Thomson-scattering computer system currently operates in three modes: user interaction and control, data acquisition and transmission, and data analysis. This paper discusses the development and implementation of this system as well as data storage and retrieval.

  20. Material Assessment for ITER's Collective Thomson Scattering first mirror

    Energy Technology Data Exchange (ETDEWEB)

    Santos, R.; Policarpo, H.; Goncalves, B.; Varela, P. [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Nonboel, E.; Klinkby, E.; Lauritzen, B. [Center for Nuclear Technologies, Technical University of Denmark (Denmark); Romanets, Y.; Luis, R.; Vaz, P. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, Universidade de Lisboa (Portugal)

    2015-07-01

    The International Thermonuclear Energy Reactor (ITER) Collective Thomson Scattering (CTS) system is a diagnostic instrument that measures plasma density and velocity through Thomson scattering of microwave radiation. Some of the key components of the CTS are quasi-optical mirrors that are used to produce astigmatic beam patterns, which have impact on the strength and spatial resolution of the diagnostic signal. The mirrors are exposed to neutron radiation, which may alter the quality of the signal received. In this work, three different materials (molybdenum (Mo), stainless steel 316 (SS-316) and tungsten (W)) are considered for the first mirror of the CTS. The objective is to access which of the material studied are best suited for this mirror, considering different neutron radiation loads simulated scenarios defined by ITER, based on the resultant stresses and temperature distributions. For it, the neutron irradiation, and subsequent heat-load on the mirrors are simulated using the Monte Carlo N-Particle (MCNP) code. Based on the MCNP heat-load results, transient thermal-structural Finite Element Analysis (FEA) of the mirror over a 400 s discharge, with and without cooling on the rear side, are conducted using in commercial FEA software ANSYS. Results show that of the tested materials Mo and W are the most suitable material for this application. Even though, this study does not yet consider the variation of the material properties with temperature, it presents a quick initial satisfactory assessment that may be considered in subsequent and more complex analysis. (authors)

  1. Conceptual design of the collection optics for the edge Thomson scattering system in ITER.

    Science.gov (United States)

    Yatsuka, E; Hatae, T; Suitoh, S; Aida, Y; Kusama, Y

    2010-10-01

    Neutron and gamma-ray irradiation complicates the design of the edge Thomson scattering (TS) system in ITER. The TS light is relayed through the relaying optics with labyrinth and fiber coupling optics. Electron density of 2×10(19) m(-3) is sufficient to measure T(e) and n(e) within a 10% and 5% margin of error, respectively, with a spatial resolution of 5 mm. This system can cover from 0.85 to 1 of the normalized minor radius. The time resolution is 10 ms, which is determined by the repetition rate of the laser device. A super-Gaussian is the ideal laser profile for the laser injection optics to avoid a breakdown of the filling gas used in density calibration through Raman scattering.

  2. Measurements of plasma composition in the TEXTOR tokamak by collective Thomson scattering

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Korsholm, Søren Bang; Nielsen, Stefan Kragh;

    2012-01-01

    with wave vector components nearly perpendicular to the magnetic field. Under such conditions the sensitivity of the CTS spectrum to plasma composition is enhanced by the spectral signatures of the ion cyclotron motion and of weakly damped ion Bernstein waves. Recent experiments on TEXTOR demonstrated......We demonstrate the use of collective Thomson scattering (CTS) for spatially localized measurements of the isotopic composition of magnetically confined fusion plasmas. The experiments were conducted in the TEXTOR tokamak by scattering millimeter-wave probe radiation off plasma fluctuations...... the ability to resolve these signatures in the CTS spectrum as well as their sensitivity to the ion species mix in the plasma. This paper shows that the plasma composition can be inferred from the measurements through forward modeling of the CTS spectrum. We demonstrate that spectra measured in plasmas...

  3. Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Stejner, M., E-mail: mspe@fysik.dtu.dk; Nielsen, S.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K.; Rasmussen, J.; Salewski, M. [Department of Physics, Association EURATOM-DTU, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Moseev, D. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, Boltzmannstr. 2, 85748 Garching (Germany); Association Euratom-FOM Institute DIFFER, 3430 BE Nieuwegein (Netherlands); Schubert, M.; Stober, J.; Wagner, D. H. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2014-09-15

    Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity, and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration, and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity, and plasma composition.

  4. Impact of ICRH on the measurement of fusion alphas by collective Thomson scattering in ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Eriksson, L.-G.; Bindslev, Henrik

    2009-01-01

    Collective Thomson scattering (CTS) has been proposed for measuring the phase space distributions of confined fast ion populations in ITER plasmas. This study determines the impact of fast ions accelerated by ion cyclotron resonance heating (ICRH) on the ability of CTS to diagnose fusion alphas......, corresponding to an off-axis resonance. The sensitivities of the results to the He-3 concentration (0.1-4%) and the heating power (20-40 MW) are considered. Fusion born alphas dominate the total CTS signal for large Doppler shifts of the scattered radiation. The tritons generate a negligible fraction...... perpendicular velocities, it may be difficult to draw conclusions about the physics of alpha particles alone by CTS. With this exception, the CTS diagnostic can reveal the physics of the fusion alphas in ITER even under the presence of fast ions due to ICRH....

  5. Semi-phenomenological analysis of neutron scattering results for quasi-two dimensional quantum anti-ferromagnet

    Science.gov (United States)

    Sarkar, Subhajit; Chaudhury, Ranjan; Paul, Samir K.

    2017-01-01

    The available results from the inelastic neutron scattering experiment performed on the quasi-two dimensional spin 1/2 anti-ferromagnetic material La2CuO4 have been analysed theoretically. The formalism of ours is based on a semi-classical like treatment involving a model of an ideal gas of mobile vortices and anti-vortices built on the background of the Néel state, using the bipartite classical spin configuration corresponding to an XY-anisotropic Heisenberg anti-ferromagnet on a square lattice. The results for the integrated intensities for our spin 1/2 model corresponding to different temperatures, show occurrence of vigorous unphysical oscillations, when convoluted with a realistic spectral window function. These results indicate failure of the conventional semi-classical theoretical model of ideal vortex/anti-vortex gas arising in the Berezinskii-Kosterlitz-Thouless theory for the low spin magnetic systems. A full fledged quantum mechanical formalism and calculations seem crucial for the understanding of topological excitations in such low spin systems. Furthermore, a severe disagreement is found to occur at finite values of energy transfer between the integrated intensities obtained theoretically from the conventional formalism and those obtained experimentally. This further suggests strongly that the full quantum treatment should also incorporate the interaction between the fragile-magnons and the topological excitations. This is quite plausible in view of the recent work establishing such a process in XXZ quantum ferromagnet on 2D lattice. The high spin XXZ quasi-two dimensional antiferromagnet like MnPS3 however follows the conventional theory quite well.

  6. Development of the so-called third stage laser Thomson scattering diagnostics of plasmas

    Science.gov (United States)

    Muraoka, Katsunori; Yamagata, Yukihiko; Hisano, Taishi; Uchino, Kiichirou; Miyazaki, Koichi

    2003-10-01

    In the recent review article,^1) we indicated that the incoherent laser Thomson scattering (LTS) diagnostics of plasmas for measurements of electron densities and temperatures (or more generally EEDFs) be classified as having evolved from the first stage where a whole Thomson spectrum be obtained during a single laser pulse from plasmas having electron density of above 10^18 m-3, through the second stage where data accumulation be prerequisite for ne below 10^18 m-3, and to the third stage where a strong suppression of stray light in addition to the data accumulation be necessary to measure at an extremely small size of less than 100 μm near to material surfaces. The third stage LTS was first demonstrated for a PDP (plasma display panel)-like discharge three years ago employing a triple grating polychromator. In order to further expand its applicable ranges, we are pursuing a more general approach by taking into account such factors as laser divergence, stray light suppression and other aspects. The present status is presented. 1) K. Muraoka, K. Uchino, Y. Yamagata, Y. Noguchi, M. Mansour, P. Suanpoot, S. Narishige, and M. Noguchi, Plasma Sources Sci. Technol. 11 (2002) A143.

  7. Progress on the multipulse Thomson Scattering diagnostic on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Stockdale, R.E.; Carlstrom, T.N.; Hsieh, C.L.; Makariou, C.C.

    1994-05-01

    The DIII-D Thomson scattering diagnostic, operational since 1990, uses 8 Nd: YAG 20 Hz lasers to measure electron temperature and density profiles (40 spatial points) throughout the plasma discharge. Recent progress has enabled a new set of operating modes to better fullfill varying plasma physics requirements. Custom circuitry for laser control (programmable with los precision) has successfully replaced a previous scheme which used real-time 68030 software. Two new modes of operation have been demonstrated. Burst Mode is useful to study a transient plasma event: a series of laser pulses axe fired at a rate {le}10 kHz after an external asynchronous event trigger. Burst Mode is also useful to synchronize the Thomson lasers with other systems, such as an asynchronous Michelson ECE diagnostic scanning near 40 Hz. Group Mode allows a programmed set of lasers to fire simultaneously into the same (65 nanosecond) data acquisition gate. Improved signal/noise then yields smaller statistical errors in the profile results. This provides profile data for lower density plasmas, such as those anticipated during fast wave current drive experiments. Plans for a new CCD-based laser alignment system for position monitoring and feedback control will also be presented.

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. Dynamic Thomson Scattering from Nonlinear Electron Plasma Waves in a Raman Plasma Amplifier

    Science.gov (United States)

    Davies, A.; Katz, J.; Bucht, S.; Haberberger, D.; Bromage, J.; Zuegel, J. D.; Froula, D. H.; Trines, R.; Bingham, R.; Sadler, J.; Norreys, P. A.

    2016-10-01

    Electron plasma waves (EPW's) can be used to transfer significant energy from a long-pulse laser to a short-pulse seed laser through the Raman scattering instability. Successful implementation of Raman amplification could open an avenue to producing high-intensity pulses beyond the capabilities of current laser technology ( 1022 W / cm 2). This three-wave interaction takes advantage of the plasma's ability to sustain large-amplitude plasma waves. Having complete knowledge of the EPW amplitude is essential to establishing optimal parameters for high-efficiency Raman amplification. A dynamic Thomson-scattering diagnostic is being developed to spatially and temporally resolve the amplitude of the driven and thermal EPW's. By imaging the scattered probe light onto a novel pulse-front tilt compensated streaked optical spectrometer, the diffraction efficiency of this plasma wave can be measured as a function of space and time. These data will be used in conjunction with particle-in-cell simulations to determine the EPW's spatial and temporal profile. This will allow the effect of the EPW profile on Raman scattering to be experimentally determined. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  13. The progress in development of edge tangential Thomson scattering system on HL-2A tokamak

    Science.gov (United States)

    Liu, C. H.; Huang, Y.; Wang, Y. Q.; Feng, Z.; Hou, Z. P.; Fu, B. Z.

    2016-11-01

    The edge tangential Thomson scattering system (ETTSS) was developed for the first time on a HL-2A tokamak. A Nd:YAG laser with a 1064 nm wavelength, 4 J energy, and 30 Hz repetition rate is employed on the ETTSS. The laser beam injects the plasma in the tangential direction on the mid-plane of the machine, and the angles between the laser injection direction and the scattered light collection direction are in the range from 157.5° to 162.8°. The scattered light collection optics with 0.21-0.47 magnification is utilized to collect the scattered light of measurement range from R = 1900 mm to 2100 mm (the normalized radius is from r/a = 0.625 to 1.125). Spatial resolution of the preliminary design could be up to Δr/a = 0.016. The measurement requirements could be achieved: 10 eV < Te < 1.5 keV, and 0.5 × 1019 m-3 < ne < 3 × 1019 m-3 with errors less than 15% and 10%, respectively.

  14. Conditions for the Observation of Two Ion-Acoustic Waves via Thomson Scattering

    Institute of Scientific and Technical Information of China (English)

    郑坚; 胡广月; 王哲斌; 俞昌旋; 刘万东

    2003-01-01

    Observation of two ion-acoustic waves via Thomson scattering can provide precise measurements of plasma parameters. The conditions for the observation of two ion-acoustic modes in a two-ion plasmaare discussed.The ratio of electron temperature Te to ion temperature Ti is the critical parameter for the presence of two ion-acoustic modes, which should be in the range of 4/ZL(<~)Te/Ti(<~)2AH/ZHAL, where ZL,H are the charge states of light and heavy ions, and AL,H are the atomic numbers of light and heavy ions, respectively. As the temperature ratio varies in this range, the concentration of heavy ions must increase with the ratio Te/Ti so that the two ion-acoustic modes can have the same fluctuation levels.

  15. Question of Acceleration of Universe Examined Within the Framework of Thomson Scattering.

    Science.gov (United States)

    Choudhury, D. C.; Kraft, David W.

    2003-04-01

    Recent observations of Type Ia supernovae appear to suggest that the universe is accelerating. These results are not only surprising but beyond the realm of any standard model of modern cosmology. Most of the new ideas proposed for understanding the acceleration include a new type of matter (dark energy or axions) or Einstein's cosmological constant. Although such attempts are reasonably successful in fitting the observed data, there is as yet no direct evidence to support the existence of such matter or energy. The present work examines whether the question of acceleration can be resolved within the limits of the established laws of physics. For this purpose we have calculated the contributions of Thomson scattering to the dimming of supernovae within the framework of Friedmann-Robertson-Walker cosmology for the special case of flat universe, also consistent with the prediction of the inflationary model. The results and conclusion of our investigation will be presented.

  16. Development of Thomson scattering system on Shenguang-III prototype laser facility

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Tao [CAS Key Laboratory of Geospace Environment and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Li, Zhichao; Jiang, Xiaohua; Ding, Yongkun, E-mail: ding-yk@vip.sina.com; Yang, Dong; Wang, Zhebin; Wang, Fang; Li, Ping; Liu, Shenye; Jiang, Shaoen [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Hu, Guangyue; Zhao, Bin [CAS Key Laboratory of Geospace Environment and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zheng, Jian, E-mail: jzheng@ustc.edu.cn [CAS Key Laboratory of Geospace Environment and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-02-15

    A Thomson scattering diagnostic system, using a 263 nm laser as the probe beam, is designed and implemented on Shenguang-III prototype laser facility. The probe beam is provided by an additional beam line completed recently. The diagnostic system allows simultaneous measurements of both ion feature and red-shifted electron feature from plasmas in a high-temperature (≥2 keV) and high-density (≥10{sup 21} cm{sup −3}) regime. Delicate design is made to satisfy the requirements for successful detection of the electron feature. High-quality ion feature spectra have already been diagnosed via this system in recent experiments with gas-filled hohlraums.

  17. Laser Thomson scattering diagnostics of non-equilibrium high pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Muraoka, K.; Uchino, K.; Bowden, M.D.; Noguchi, Y. [Kyushu Univ., Fukuoka (Japan). Interdisciplinary Graduate School of Engineering Sciences

    2001-07-01

    For various applications of non-equilibrium high pressure plasmas, knowledge of electron properties, such as electron density, electron temperature and/or electron energy distribution function (eedf), is prerequisite for any rational approach to understanding physical and chemical processes occurring in the plasmas. For this purpose, laser Thomson scattering has been successfully applied for the first time to measure the electron properties in plasmas for excimer laser pumping and in microdischarges. Although this diagnostic technique is well established for measurements in high temperature plasmas, its applications to these glow discharge plasmas have had various inherent difficulties, such as a presence of high density neutral particles (>10{sup 21} m{sup -3}) in the excimer laser pumping discharges and an extremely small plasma size (<0.1 mm) and the presence of nearby walls for microdischarges. These difficulties have been overcome and clear signals have been obtained. The measured results are presented and their implications in the respective discharge phenomena are discussed.

  18. Recent results of collective Thomson scattering on TEXTOR and plans for CTS on ITER

    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...

  19. 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...

  20. Data-driven sensitivity inference for Thomson scattering electron density measurement systems

    Science.gov (United States)

    Fujii, Keisuke; Yamada, Ichihiro; Hasuo, Masahiro

    2017-01-01

    We developed a method to infer the calibration parameters of multichannel measurement systems, such as channel variations of sensitivity and noise amplitude, from experimental data. We regard such uncertainties of the calibration parameters as dependent noise. The statistical properties of the dependent noise and that of the latent functions were modeled and implemented in the Gaussian process kernel. Based on their statistical difference, both parameters were inferred from the data. We applied this method to the electron density measurement system by Thomson scattering for the Large Helical Device plasma, which is equipped with 141 spatial channels. Based on the 210 sets of experimental data, we evaluated the correction factor of the sensitivity and noise amplitude for each channel. The correction factor varies by ≈10%, and the random noise amplitude is ≈2%, i.e., the measurement accuracy increases by a factor of 5 after this sensitivity correction. The certainty improvement in the spatial derivative inference was demonstrated.

  1. Investigation of the local thermodynamic equilibrium of laser-induced aluminum plasma by Thomson scattering technique

    Energy Technology Data Exchange (ETDEWEB)

    Mendys, A., E-mail: agata.mendys@uj.edu.pl [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagielloński, ul. Reymonta 4, 30-059 Kraków (Poland); Kański, M. [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagielloński, ul. Reymonta 4, 30-059 Kraków (Poland); Farah-Sougueh, A. [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagielloński, ul. Reymonta 4, 30-059 Kraków (Poland); GREMI — site de Bourges, Université d' Orléans, CNRS, rue Gaston Berger BP 4043, 18028 Bourges (France); Pellerin, S. [GREMI — site de Bourges, Université d' Orléans, CNRS, rue Gaston Berger BP 4043, 18028 Bourges (France); Pokrzywka, B. [Obserwatorium Astronomiczne na Suhorze, Uniwersytet Pedagogiczny, ul. Podchorażych 2, 30-084 Kraków (Poland); Dzierżęga, K. [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagielloński, ul. Reymonta 4, 30-059 Kraków (Poland)

    2014-06-01

    A laser Thomson scattering method was applied to investigate the local Saha–Boltzmann equilibrium in aluminum laser-induced plasma. Plasma was created in ambient air using 4.5 ns pulses from a Nd:YAG laser at 532 nm, focused on an Al target. Spatially resolved measurements, performed for the time interval between 600 ns and 3 μs, show electron density and temperature to decrease from 3.4 × 10{sup 23} m{sup −3} to 0.5 × 10{sup 23} m{sup −3} and from 61,000 K to 13,000 K in the plasma core. The existence of local thermodynamic equilibria in the plasma was verified by comparing the rates of the collisional to radiative processes (the McWhirter criterion), as well as relaxation times and diffusion lengths of different plasma species, with the appropriate rate of electron density evolution and its gradients at given, experimentally determined, electron temperatures. We found these criteria to be much easier to satisfy for metallic plasma species than for nitrogen. The criteria are also easier to satisfy in the plasma core of higher electron density. - Highlights: • Laser Thomson scattering method was applied to investigate aluminum laser-induced plasma. • Spatio-temporal evolution of electron temperature and density was determined. • Three criteria for existence of local thermodynamic equilibrium were verified. • Criteria are much easier to satisfy for metallic plasma species than for nitrogen. • Criteria are easier to satisfy at earlier times and in the plasma core.

  2. Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter.

    Science.gov (United States)

    Johnson, W R; Nilsen, J

    2016-03-01

    The influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity and also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.

  3. Diagnosing Pulsed Power Produced Plasmas with X-ray Thomson Scattering at the Nevada Terawatt Facility

    Science.gov (United States)

    Valenzuela, J. C.; Krauland, C.; Mariscal, D.; Krasheninnikov, I.; Beg, F. N.; Wiewior, P.; Covington, A.; Presura, R.; Ma, T.; Niemann, C.; Mabey, P.; Gregori, G.

    2015-11-01

    We present experimental results on X-ray Thomson scattering (XRTS) at the Nevada Terawatt Facility (NTF) to study current driven plasmas. Using the Leopard laser, ~ 30 J and pulse width of 0.8 ns, we generated He- α emission (4.75 keV) from a thin Ti foil. Initial parameter scans showed that the optimum intensity is ~ 1015W/cm2 with a foil thickness of 2 μm for forward X-ray production. Bandwidth measurements of the source, using a HAPG crystal in the Von Hamos configuration, were found to be ΔE/E ~ 0.01. Giving the scattering angle of our experimental setup of 129 degrees and X-ray probing energy, the non-collective regime was accessed. The ZEBRA load was a 3 mm wide, 500 μm thick, and 10 mm long graphite foil, placed at one of the six current return posts. Estimates of the plasma temperature, density and ionization state were made by fitting the scattering spectra with dynamic structure factor calculations based on the random phase approximation for the treatment of charged particle coupling. The work was partially funded by the Department of Energy grant number DE-NA0001995.

  4. Demonstration of imaging X-ray Thomson scattering on OMEGA EP

    Science.gov (United States)

    Belancourt, Patrick X.; Theobald, Wolfgang; Keiter, Paul A.; Collins, Tim J. B.; Bonino, Mark J.; Kozlowski, Pawel M.; Regan, Sean P.; Drake, R. Paul

    2016-11-01

    Foams are a common material for high-energy-density physics experiments because of low, tunable densities, and being machinable. Simulating these experiments can be difficult because the equation of state is largely unknown for shocked foams. The focus of this experiment was to develop an x-ray scattering platform for measuring the equation of state of shocked foams on OMEGA EP. The foam used in this experiment is resorcinol formaldehyde with an initial density of 0.34 g/cm3. One long-pulse (10 ns) beam drives a shock into the foam, while the remaining three UV beams with a 2 ns square pulse irradiate a nickel foil to create the x-ray backlighter. The primary diagnostic for this platform, the imaging x-ray Thomson spectrometer, spectrally resolves the scattered x-ray beam while imaging in one spatial dimension. Ray tracing analysis of the density profile gives a compression of 3 ± 1 with a shock speed of 39 ± 6 km/s. Analysis of the scattered x-ray spectra gives an upper bound temperature of 20 eV.

  5. Development of a Thomson scattering diagnostic for the Caltech jet-target experiment

    Science.gov (United States)

    Seo, Byong Hoon; Greig, Amelia; Bellan, Paul

    2016-10-01

    A Thomson scattering diagnostic is being developed for studying the Caltech jet-target impact experiment. This experiment has a high-speed MHD-driven jet impact a dense, high-mass target cloud. The compression of the jet upon impact simulates the compression of an imploding liner. A preliminary bench top system consisting of a low power laser, lenses, a beam rotator, a monochromator, and a PMT is being used for measuring the Rayleigh and eventually Raman scattering signals from atmospheric pressure N2 and O2. The laser is modulated at 500 Hz to 1 kHz and lock-in techniques are used to recover the low-amplitude signal. For the actual pulsed plasma experiment, the low-power laser will be replaced by a high power Nd:YAG laser. The detector will consist of a double monochromator consisting of two single monochromators separated by a mask in the focal plane to block Rayleigh scattered light; detection will be by an intensified, gated camera. The diagnostic will be used to study the compression and heating that occurs when the jet plasma collides with a dense, high mass target cloud. Supported by USDOE Grant DE-AR0000565.

  6. First results of electron temperature measurements by the use of multi-pass Thomson scattering system in GAMMA 10

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, M., E-mail: yosikawa@prc.tsukuba.ac.jp; Nagasu, K.; Shimamura, Y.; Shima, Y.; Kohagura, J.; Sakamoto, M.; Nakashima, Y.; Imai, T.; Ichimura, M. [Plasma Research Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Yasuhara, R.; Yamada, I.; Funaba, H.; Kawahata, K. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Minami, T. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2014-11-15

    A multi-pass Thomson scattering (TS) has the advantage of enhancing scattered signals. We constructed a multi-pass TS system for a polarisation-based system and an image relaying system modelled on the GAMMA 10 TS system. We undertook Raman scattering experiments both for the multi-pass setting and for checking the optical components. Moreover, we applied the system to the electron temperature measurements in the GAMMA 10 plasma for the first time. The integrated scattering signal was magnified by approximately three times by using the multi-pass TS system with four passes. The electron temperature measurement accuracy is improved by using this multi-pass system.

  7. The upgrade of the Thomson scattering system for measurement on the C-2/C-2U devices

    Science.gov (United States)

    Zhai, K.; Schindler, T.; Kinley, J.; Deng, B.; Thompson, M. C.

    2016-11-01

    The C-2/C-2U Thomson scattering system has been substantially upgraded during the latter phase of C-2/C-2U program. A Rayleigh channel has been added to each of the three polychromators of the C-2/C-2U Thomson scattering system. Onsite spectral calibration has been applied to avoid the issue of different channel responses at different spots on the photomultiplier tube surface. With the added Rayleigh channel, the absolute intensity response of the system is calibrated with Rayleigh scattering in argon gas from 0.1 to 4 Torr, where the Rayleigh scattering signal is comparable to the Thomson scattering signal at electron densities from 1 × 1013 to 4 × 1014 cm-3. A new signal processing algorithm, using a maximum likelihood method and including detailed analysis of different noise contributions within the system, has been developed to obtain electron temperature and density profiles. The system setup, spectral and intensity calibration procedure and its outcome, data analysis, and the results of electron temperature/density profile measurements will be presented.

  8. Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures less than 1 keV

    Energy Technology Data Exchange (ETDEWEB)

    Ross, James Steven [Univ. of California, San Diego, CA (United States)

    2010-01-01

    Simultaneous scattering from electron-plasma waves and ion-acoustic waves is used to measure local laser-produced plasma parameters with high spatiotemporal resolution including electron temperature and density, average charge state, plasma flow velocity, and ion temperature. In addition, the first measurements of relativistic modifications in the collective Thomson scattering spectrum from thermal electron-plasma fluctuations are presented [1]. Due to the high phase velocity of electron-plasma fluctuations, relativistic effects are important even at low electron temperatures (Te < 1 keV). These effects have been observed experimentally and agree well with a relativistic treatment of the Thomson scattering form factor [2]. The results are important for the interpretation of scattering measurements from laser produced plasmas. Thomson scattering measurements are used to characterize the hydrodynamics of a gas jet plasma which is the foundation for a broad series of laser-plasma interaction studies [3, 4, 5, 6]. The temporal evolution of the electron temperature, density and ion temperature are measured. The measured electron density evolution shows excellent agreement with a simple adiabatic expansion model. The effects of high temperatures on coupling to hohlraum targets is discussed [7]. A peak electron temperature of 12 keV at a density of 4.7 × 1020cm-3 are measured 200 μm outside the laser entrance hole using a two-color Thomson scattering method we developed in gas jet plasmas [8]. These measurements are used to assess laser-plasma interactions that reduce laser hohlraum coupling and can significantly reduce the hohlraum radiation temperature.

  9. Upgrades to improve the usability, reliability, and spectral range of the MST Thomson scattering diagnostic

    Science.gov (United States)

    Kubala, S. Z.; Borchardt, M. T.; Den Hartog, D. J.; Holly, D. J.; Jacobson, C. M.; Morton, L. A.; Young, W. C.

    2016-11-01

    The Thomson scattering diagnostic on MST records both equilibrium and fluctuating electron temperature with a range capability of 10 eV-5 keV. Standard operation with two modified commercial Nd:YAG lasers allows measurements at rates of 1 kHz-25 kHz. Several subsystems of the diagnostic are being improved. The power supplies for the avalanche photodiode detectors (APDs) that record the scattered light are being replaced to improve usability, reliability, and maintainability. Each of the 144 APDs will have an individual rack mounted switching supply, with bias voltage adjustable to match the APD. Long-wavelength filters (1140 nm center, 80 nm bandwidth) have been added to the polychromators to improve capability to resolve non-Maxwellian distributions and to enable directed electron flow measurements. A supercontinuum (SC) pulsed white light source has replaced the tungsten halogen lamp previously used for spectral calibration of the polychromators. The SC source combines substantial brightness produced in nanosecond pulses with a spectrum that covers the entire range of the polychromators.

  10. Design of the Collective Thomson scattering (CTS) system by using 170-GHz gyrotron in the KSTAR

    Science.gov (United States)

    Park, Min; Kim, Sun-Ho; Kim, Sung-Kyu; Lee, Kyu-Dong; Wang, Son-Jong

    2014-10-01

    The physics of energetic ions is one of the primary subjects to be understood toward the realization of a nuclear fusion power plant. Collective Thomson scattering (CTS) offers the possibility to diagnose the fast ions and the alpha particles in burning plasmas. Spatially- and temporally-resolved one-dimensional velocity distributions of the fast ions can be obtained from the scattered radiation with fewer geometric constraints by utilizing millimeter waves from a high-power gyrotron as a probe beam. We studied the feasibility of CTS fast-ion measurements in the KSTAR by calculating the spectral density functions. Based on that, we suggest a design for the CTS system that uses the currently-operating 170-GHz gyrotron for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) in the KSTAR. The CTS system is presented as two subsystems: the antenna system and the heterodyne receiver system. The design procedure for an off-axis ellipsoidal mirror is described, and the CTS system requirements are discussed.

  11. The design of the optical Thomson scattering diagnostic for the National Ignition Facility

    Science.gov (United States)

    Datte, P. S.; Ross, J. S.; Froula, D. H.; Daub, K. D.; Galbraith, J.; Glenzer, S.; Hatch, B.; Katz, J.; Kilkenny, J.; Landen, O.; Manha, D.; Manuel, A. M.; Molander, W.; Montgomery, D.; Moody, J.; Swadling, G. F.; Weaver, J.

    2016-11-01

    The National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion (ICF) programs. We report on the design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community's understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beam splitter and gratings before the shot. A deep-UV probe beam (λ0-210 nm) will be used to optimize the scattered signal for plasma densities of 5 × 1020 electrons/cm3 while a 3ω probe will be used for experiments investigating lower density plasmas of 1 × 1019 electrons/cm3. We report the phase I design of a two phase design strategy. Phase I includes the OTS telescope, spectrometer, and streak camera; these will be used to assess the background levels at NIF. Phase II will include the design and installation of a probe laser.

  12. 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.

  13. Asphericalizing the Light Collection Mirror for the 200-Point Thomson Scattering Diagnostic Installed on the Large Helical Device%Asphericalizing the Light Collection Mirror for the 200-Point Thomson Scattering Diagnostic Installed on the Large Helical Device

    Institute of Scientific and Technical Information of China (English)

    Kazumichi NARIHARA; Hiroshi HAYASHI

    2011-01-01

    Shown is a possibility to make the image of a laser beam over a distance of 2.5 m, formed by the spherical multi-segment mirror installed in LHD, twice sharper by suitably adjusting the inclination of each segment mirror, which is equivalent to making the mirror surface aspherical. This will further enhance the attractiveness of a mirror-based Thomson scattering system.

  14. Thomson scattering laser-electron X-ray source for reduction of patient radiation dose in interventional coronary angiography

    Science.gov (United States)

    Artyukov, I. A.; Dyachkov, N. V.; Feshchenko, R. M.; Polunina, A. V.; Popov, N. L.; Shvedunov, V. I.; Vinogradov, A. V.

    2017-05-01

    It was medical applications that stimulated F. Carrol in the early 1990s to start the research of on relativistic Thomson scattering X-ray sources, as a part of the infrastructure of the future society. The possibility to use such a source in interventional cardiology is discussed in this paper. The replacement of X-ray tube by relativistic Thomson scattering Xray source is predicted to lower the patient radiation dose by a factor of 3 while image quality remains the same. The required general characteristics of accelerator and laser units are found. They can be reached by existing technology. A semiempirical method for simulation of medical and technical parameters of interventional coronary angiography systems is suggested.

  15. Relativistic correction of (v/c)2 to the collective Thomson scattering for high-temperature high-density plasma

    Institute of Scientific and Technical Information of China (English)

    Jiang Chen-Fan-Fu; Zheng Jian; Zhao Bin

    2011-01-01

    Collective Thomson scattering is theoretically investigated with the inclusion of the relativistic correction of (v/c)2.The correction is rather small for the plasma parameters inferred from the spectra of the thermal electron plasma waves in the plasma. Since the full formula of the corrected result is rather complicated,a simplified one is derived for practical use,which is shown to be in good agreement with the un-simplified one.

  16. Reentrant resistance and giant Andreev back scattering in a two-dimensional electron gas coupled to superconductors

    NARCIS (Netherlands)

    den Hartog, Sander; Wees, B.J. van; Nazarov, Yu.V.; Klapwijk, T.M.; Borghs, G.

    1998-01-01

    We first present the bias-voltage dependence of the superconducting phase-dependent reduction in the differential resistance of a disordered T-shaped two-dimensional electron gas (2DEG) coupled to two superconductors. This reduction exhibits a reentrant behavior, since it first increases upon loweri

  17. Thomson scattering system on the TEXTOR tokamak using a multi-pass laser beam configuration

    Energy Technology Data Exchange (ETDEWEB)

    Kantor, M Yu; Donne, A J H; Jaspers, R; Van der Meiden, H J [FOM-Institute for Plasma Physics Rijnhuizen , Association EURATOM-FOM, PO Box 1207, 3430 BE Nieuwegein (Netherlands)], E-mail: m.kantor@fz-juelich.de

    2009-05-15

    The main challenge for the Thomson scattering (TS) diagnostic on the TEXTOR tokamak is the detailed study of fast plasma events at a high spatial resolution and a high repetition rate of the measurements. The diagnostic uses intra-cavity probing of the plasma with a repetitively pulsed ruby laser and a fast CMOS camera as detectors. Since 2004, the TS system on TEXTOR has been gradually and systematically enhanced for the measurements of fast plasma events. For that it has recently been upgraded to obtain a multi-pass configuration. Two spherical mirrors have been installed that force the laser beam to probe the plasma a specified number of times before it is directed back into the laser medium. The diagnostics with the upgraded probing system have achieved the measurement accuracy of 3% for the electron temperature and 1.5% for the electron density at <1 cm spatial resolution and 3 x 10{sup 19} m{sup -3} plasma density and can measure at 5 kHz during an interval up to 8 ms. This makes it possible to detect, amongst others, fine structures of magnetic islands and variations of the edge pedestal in the ELMy limiter H-mode.

  18. Measurements with the fast repetitive multi-pulse Edge Thomson Scattering system on TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Uzgel, Evren; Pospieszczyk, Albrecht; Unterberg, Bernhard [IEF-Plasmaphysik, Forschungszentrum Juelich, 52425 Juelich (Germany); Kantor, Mikhail [Ioffe Institute, RAS, Saint Petersburg (Russian Federation); Meiden, Hennie van der; Jaspers, Roger [FOM-Institute for Plasma Physics Rijnhuizen, Nieuwegein (Netherlands)

    2008-07-01

    A fast repetitive multi-pulse Edge Thomson Scattering system is in operation since March 2006 and provides a sophisticated tool for the study of transport processes in the edge region of the tokamak TEXTOR. The specially designed viewing optics enables the study of the dynamics of fast plasma phenomena with high spatial resolution at the plasma edge. Various measurements under different plasma conditions were performed where the influence of resonant magnetic perturbations generated by the Dynamic Ergodic Divertor on fast electron transport in the edge region was a point of emphasis. The electron density and temperature profiles obtained are compared with other edge diagnostics based on different measuring principles. The system utilizes a ruby laser delivering bursts of 15 pulses each with a pulse energy of about 15 J. The TEXTOR plasma itself is inside the laser cavity where the double-pass system allows high laser energies of each laser pulse through the plasma. The edge system (170 mm) has 98 spatial channels of 1.7 mm each. The lower detection limit of the edge system for T{sub e} is observed to be 30 eV.

  19. Thomson scattering system on the TEXTOR tokamak using a multi-pass laser beam configuration

    Science.gov (United States)

    Kantor, M Yu; Donné, A J H; Jaspers, R; van der Meiden, H J; TEXTOR Team

    2009-05-01

    The main challenge for the Thomson scattering (TS) diagnostic on the TEXTOR tokamak is the detailed study of fast plasma events at a high spatial resolution and a high repetition rate of the measurements. The diagnostic uses intra-cavity probing of the plasma with a repetitively pulsed ruby laser and a fast CMOS camera as detectors. Since 2004, the TS system on TEXTOR has been gradually and systematically enhanced for the measurements of fast plasma events. For that it has recently been upgraded to obtain a multi-pass configuration. Two spherical mirrors have been installed that force the laser beam to probe the plasma a specified number of times before it is directed back into the laser medium. The diagnostics with the upgraded probing system have achieved the measurement accuracy of 3% for the electron temperature and 1.5% for the electron density at <1 cm spatial resolution and 3 × 1019 m-3 plasma density and can measure at 5 kHz during an interval up to 8 ms. This makes it possible to detect, amongst others, fine structures of magnetic islands and variations of the edge pedestal in the ELMy limiter H-mode.

  20. Measurements with the fast repetitive multi-pulse Edge Thomson scattering system on TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Uzgel, Evren; Pospieszczyk, Albrecht; Unterberg, Bernhard [Institut fuer Plasmaphysik, Forschungszentrum Juelich, 52425 Juelich (Germany); Kantor, Mikhail; Kouprienko, Denis [Ioffe Institute, RAS, Saint Petersburg (Russian Federation); Meiden, Hennie van der; Oyevaar, Theo; Jaspers, Roger [FOM-Institute for Plasma Physics Rijnhuizen, Nieuwegein (Netherlands)

    2007-07-01

    A fast repetitive multi-pulse Edge Thomson Scattering system is in operation since March 2006 and provides a sophisticated tool for the study of transport processes in the edge region of the tokamak TEXTOR. The specially designed viewing optics enables the study of the dynamics of fast plasma phenomena with high spatial resolution at the plasma edge. Various measurements under different plasma conditions were performed where the influence of resonant magnetic perturbations generated by the Dynamic Ergodic Divertor on fast electron transport in the edge region was a point of emphasis. The electron density and temperature profiles obtained will be compared with other edge diagnostics based on different measuring principles. The system utilizes a ruby laser delivering bursts of 15 pulses each with a pulse energy of about 15 J. The TEXTOR plasma itself is inside the laser cavity where the double-pass system allows high laser energies of each laser pulse through the plasma. The new edge system (170 mm) has 98 spatial channels of 1.7 mm each. The lower detection limit of the edge system for T{sub e} is observed to be 30 eV.

  1. Development of density measurement method of negative ion in plasmas using laser Thomson scattering

    Science.gov (United States)

    Yamagata, Yukihiko; Saiho, Hiroatsu; Uchino, Kiichiro; Muraoka, Katsunori

    2004-09-01

    Measurements of negative ion density in plasmas have been an important subject for many years. We have proposed a new method to measure the negative ion density in plasmas using laser Thomson scattering (LTS), and successfully measured O^- ion density in an radio frequency inductively coupled plasma [1]. In order to ensure the reliability of this technique and to estimate the accuracy, we have measured O^- ion density in the same experimental conditions using the second (SHG) and third harmonics (THG) of a Nd:YAG laser as different laser sources. The LTS spectra measured at pure argon plasma (500 W, 20 mTorr) fitted in a straight line well in both SHG and THG cases. As for the plasma at 500 W in 20 mTorr with Ar/O_2=95%/5%, a clear bump in LTS spectra, which is caused by photo-detached electrons, was observed below 0.9 eV for the SHG case and 2 eV for the case, as predicted by a difference between the electron affinity of O^- ion and the laser photon energy. The electron temperatures, the electron densities and the O^- ion densities, which were obtained from the spectral shape and intensity of both LTS spectra, were in agreement each other within an experimental error. [1] M. Noguchi, K. Ariga, T. Hirao, P. Suanpoot, Y. Yamagata, K. Uchino, K. Muraoka, Plasma Sources Sci. Technol., 11 (2002) 57.

  2. Spectrometer Development in Support of Thomson Scattering Investigations for the Helicon Plasma Experiment (HPX)

    Science.gov (United States)

    Sandri, Eva; Davies, Richard; Azzari, Phil; Frank, John; Frank, Jackson; James, Royce; Hopson, Jordon; Duke-Tinson, Omar; Paolino, Richard; Sherman, Justin; Wright, Erin; Turk, Jeremy

    2016-10-01

    Now that reproducible plasmas have been created on the Helicon Plasma Experiment (HPX) at the Coast Guard Academy Plasma Laboratory (CGAPL), a high-performance spectrometer utilizing volume-phase-holographic (VPH) grating and a charge coupled device (CCD) camera with a range of 380-1090 nm and resolution of 1024x1024 is being assembled. This spectrometer will collect doppler shifted photons created by exciting the plasma with the first harmonic of a 2.5 J Nd:YAG laser at a wavelength of 1064 nm. Direct measurements of the plasma's temperature and density will be determined using HPX's Thomson Scattering (TS) system as a single spatial point diagnostic. TS has the capability of determining plasma properties on short time scales and will be used to create a robust picture of the internal plasma parameters. A prototype spectrometer has been constructed to explore the Andor CCD camera's resolution and sensitivity. Concurrently, through intensive study of the high energy TS system, safety protocols and standard operation procedures (SOP) for the Coast Guard's largest and most powerful Laser have been developed. The current status of the TS SOP, diagnostic development, and the collection optic's spectrometer will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY15-16.

  3. 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.

  4. A compact, low cost, 7 channel polychromator for Thomson scattering measurements

    Energy Technology Data Exchange (ETDEWEB)

    Carlstrom, T.N.; DeBoo, J.C.; Evanko, R.; Greenfield, C.M.; Hsieh, C.-L.; Snider, R.T.; Trost, P.

    1990-10-01

    A seven channel polychromator, utilizing high performance interference filters, has been tested for use in the multi-Nd:YAG laser Thomson scattering system for the DIII-D tokamak. Unique features of this polychromator are the combination of high throughput, easy alignment, flexibility, compact size, and low cost when compared with other alternatives. Light is introduced to the polychromator (f/1.75) via a fiber optic bundle which permits the use of small (3.0 cm dia) optics and leads to a compact design, an important design consideration for multiple polychromator systems. The light is cascaded through a series of different bandpass interference filters and relay lenses which are mounted on two precision parallel rails in such a way that alignment is trivial. The relay lenses are positioned directly in front of the filters so that light reflected from the filter passes through the lens twice. This leads to an efficient, compact design and reduces the angle of incidence (4{degree}) and the cone angle of light (4.5{degree}) seen by the filter, an important factor for narrowband (3.0 nm) filters. The transmission was optimized for 700--1100 nm by using broadband coatings throughout. The output images of each channel (2.3 mm dia) can be directly coupled to large format (3 nm dia) RCA silicon avalanche photodiode detectors, avoiding the losses caused by fiber optic coupling.

  5. 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...

  6. Study of Fast, Near-Infrared Photodetectors for the ITER Core LIDAR Thomson Scattering

    Science.gov (United States)

    Giudicotti, L.; Pasqualotto, R.; Alfier, A.; Beurskens, M.; Kempenaars, M.; Walsh, M. J.

    2008-03-01

    A key component for the ITER core LIDAR Thomson Scattering (TS) diagnostic would be a detector with good sensitivity in the 850-1060 nm near infrared (NIR) spectral region. Covering this spectral region becomes necessary if a Nd:YAG laser system operating at λ = 1.06 μm is used as the laser source, which is a very attractive choice in terms of available energy, repetition rate, reliability and cost. In this paper we review the state of the art of two types of detectors available for the above spectral range: the transferred electron (TE) InGaAs/InP hybrid photodiode and the InxGa1-xAs microchannel plate (MCP) image intensifier and we describe the advancements necessary for a possible application in the ITER LIDAR TS. In addition we describe the preliminary characterization of new GaAsP fast MCP photomultipliers (PMTs) suitable for the detection of the visible part of the LIDAR TS spectrum in JET and ITER.

  7. The Thomson Scattering System on the Lithium Tokamak eXperiment (LTX)

    Energy Technology Data Exchange (ETDEWEB)

    T. Strickler, R. Majeski, R. Kaita, B. LeBlanc

    2008-07-31

    The Lithium Tokamak eXperiment (LTX) is a spherical tokamak with R0 = 0.4m, a = 0.26m, BTF ~ 3.4kG, IP ~ 400kA, and pulse length ~ 0.25s. The goal of LTX is to investigate tokamak plasmas that are almost entirely surrounded by a lithium-coated plasma-facing shell conformal to the last closed magnetic flux surface. Based on previous experimental results and simulation, it is expected that the low-recycling liquid lithium surfaces will result in higher temperatures at the plasma edge, flatter overall temperature profiles, centrally-peaked density profiles, and an increased confinement time. To test these predictions, the electron temperature and density profiles in LTX will be measured by a multi-point Thomson scattering system (TVTS). Initially, TS measurements will be made at up to 12 simultaneous points between the plasma center and plasma edge. Later, high resolution edge measurements will be deployed to study the lithium edge physics in greater detail. Technical challenges to implementing the TS system included limited "line of sight" access to the plasma due to the plasma-facing shell and problems associated with the presence of liquid lithium.

  8. Thomson scattering diagnostic system design for the Compact Toroidal Hybrid experiment

    Energy Technology Data Exchange (ETDEWEB)

    Traverso, P. J., E-mail: pjt0002@auburn.edu; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.; Goforth, M. M.; Loch, S. D.; Pearce, A. J.; Cianciosa, M. R. [Physics Department, Auburn University, Auburn, Alabama 36849 (United States)

    2014-11-15

    A new Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The beam, generated by a frequency doubled Continuum PL DLS 2 J Nd:YAG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize the stray laser light that could enter the collection optics. The beam line has been designed with an 8 m propagation distance to the mid-plane of the CTH device with the beam diameter kept less than 3 mm inside the plasma volume. The beam exits the vacuum system through another Brewster window and enters a beam dump, again to minimize the stray light in the vacuum chamber. Light collection, spectral processing, and signal detection are accomplished with an f/#∼ 1 aspheric lens, a commercially available Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. Spectral rejection of stray laser light, if needed, can be performed with the use of an optional interference filter at the spectrometer input. The system has been developed for initial single point measurements of plasmas with core electron temperatures of approximately 20–300 eV and densities of 5 × 10{sup 18} to 5 × 10{sup 19} m{sup −3} dependent upon operational scenario.

  9. Installation of a Thomson scattering diagnostic on the Compact Toroidal Hybrid Experiment

    Science.gov (United States)

    Traverso, P. J.; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.; Cianciosa, M. R.

    2015-11-01

    A Thomson scattering system is being commissioned for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH), a five-field period current-carrying torsatron. The initial system takes a single point measurement on the magnetic axis and will be used to assess options for an expansion to a multi-point system to enable better 3D equilibrium reconstructions using the V3FIT code. A single point measurement will reduce the uncertainty in the reconstructed peak pressure by an order of magnitude for both current-carrying plasmas and future gyrotron-heated stellarator plasmas. The beam, generated by a frequency doubled Continuum 2 J, Nd:YaG laser, is passed vertically through an entrance Brewster window and a two-aperture optical baffle system to minimize stray light. The beam line is designed to propagate ~ 8 m to the mid-plane of the CTH device with the beam diameter < 3 mm inside the plasma volume. An Andor iStar DH740-18U-C3 image intensified CCD camera is used in conjunction with a Holospec f/1.8 spectrograph to collect the red-shifted scattered light from 532-580 nm. A single point system will initially measure plasmas with core electron temperatures of 100 to 200 eV and densities of 5 ×1018 to 5 ×1019 m-3. This work is supported by U.S. Department of Energy Grant No. DE-FG02-00ER54610.

  10. Light Focusing and Two-Dimensional Imaging Through Scattering Media using the Photoacoustic Transmission-Matrix with an Ultrasound Array

    CERN Document Server

    Chaigne, Thomas; Katz, Ori; Bossy, Emmanuel; Gigan, Sylvain

    2014-01-01

    We implement the photoacoustic transmission-matrix approach on a two-dimensional photoacoustic imaging system, using a 15 MHz linear ultrasound array. Using a black leaf skeleton as a complex absorbing structure, we demonstrate that the photoacoustic transmission-matrix approach allows to reveal structural features that are invisible in conventional photoacoustic images, as well as to selectively control light focusing on absorbing targets, leading to a local enhancement of the photoacoustic signal.

  11. Comprehensive two-dimensional liquid chromatography with ultraviolet, evaporative light scattering and mass spectrometric detection of triacylglycerols in corn oil

    NARCIS (Netherlands)

    Klift, van der E.J.C.; Vivó-Truyols, G.; Claassen, F.W.; Holthoon, van F.L.; Beek, van T.A.

    2008-01-01

    An improved comprehensive two-dimensional (LC × LC) HPLC system for the analysis of triacylglycerols was developed. In the first-dimension, a Ag(I)-coated cation exchanger (250 mm × 2.1 mm, 5 ¿m) was employed with a gradient from 100% MeOH to 6% MeCN in MeOH at 20 ¿L/min. Using a 10-way valve with t

  12. 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

  13. Calculation of the nonlinear relativistic Thomson scattering fields and Its application to electron distribution function diagnostic

    Science.gov (United States)

    Guasp, J.; Pastor, I.; Álvarez-Estrada, R. F.; Castejón, F.

    2015-02-01

    Analytical results obtained recently of the ab-initio classical incoherent Thomson Scattering (TS) spectrum from a single-electron (Alvarez-Estrada et al 2012 Phys. Plasmas 19 062302) have been numerically implemented in a paralelized code to efficiently compute the TS emission from a given electron distribution function, irrespective of its characteristics and/or the intensity of the incoming radiation. These analytical results display certain differences, when compared with other authors, in the general case of incoming linearly and circularly polarized radiation and electrons with arbitrary initial directions. We regard such discrepancies and the ubiquitous interest in TS as motivations for this work. Here, we implement some analytical advances (like generalized Bessel functions for incoming linearly polarized radiation) in TS. The bulk of this work reports on the efficient computation of TS spectra (based upon our analytical approach), for an electron population having an essentially arbitrary distribution function and for both incoming linearly and circularly polarized radiation. A detailed comparison between the present approach and a previous Monte Carlo one (Pastor et al 2011 Nuclear Fusion 51 043011), dealing with the ab-initio computation of TS spectra, is reported. Both approaches are shown to fully agree with each other. As key computational improvements, the analytical technique yields a × 30 to × 100 gain in computation time and is a very flexible tool to compute the scattered spectrum and eventually the scattered electromagnetic fields in the time domain. The latter are computed explicitly here for the first time, as far as we know. Scaling laws for the power integrated over frequency versus initial kinetic energy are studied for the case of isotropic and monoenergetic electron distribution functions and their potential application as diagnostic tools for high-energy populations is briefly discussed. Finally, we discuss the application of these

  14. Initial Thomson Scattering Survey of Local Helicity Injection and Ohmic Plasmas at the Pegasus Toroidal Experiment

    Science.gov (United States)

    Schlossberg, D. J.; Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Winz, G. R.

    2014-10-01

    A multipoint Thomson scattering diagnostic has recently been installed on the Pegasus ST. The system utilizes a frequency-doubled Nd:YAG laser (λ0 ~ 532 nm), spectrometers with volume phase holographic gratings, and a gated, intensified CCD camera. It provides measurements of Te and ne at 8 spatial locations for each spectrometer once per discharge. A new multiple aperture and beam dump system has been implemented to mitigate interference from stray light. This system has provided initial measurements in the core region of plasmas initiated by local helicity injection (LHI), as well as conventional Ohmic L- and H-mode discharges. Multi-shot averages of low-density (ne ~ 3 ×1018 m-3) , Ip ~ 0 . 1 MA LHI discharges show central Te ~ 75 eV at the end of the helicity injection phase. Ip ~ 0 . 13 MA Ohmic plasmas at moderate densities (ne ~ 2 ×1019 m-3) have core Te ~ 150 eV in L-mode. Generally, these plasmas do not reach transport equilibrium in the short 25 ms pulse length available. After an L-H transition, strong spectral broadening indicates increasing Te, to values above the range of the present spectrometer system with a high-dispersion VPH grating. Near-term system upgrades will focus on deploying a second spectrometer, with a lower-dispersion grating capable of measuring the 0.1-1.0 keV range. The second spectrometer system will also increase the available number of spatial channels, enabling study of H-mode pedestal structure. Work supported by US DOE Grant DE-FG02-96ER54375.

  15. Bistatic scattering from a three-dimensional object above a two-dimensional randomly rough surface modeled with the parallel FDTD approach.

    Science.gov (United States)

    Guo, L-X; Li, J; Zeng, H

    2009-11-01

    We present an investigation of the electromagnetic scattering from a three-dimensional (3-D) object above a two-dimensional (2-D) randomly rough surface. A Message Passing Interface-based parallel finite-difference time-domain (FDTD) approach is used, and the uniaxial perfectly matched layer (UPML) medium is adopted for truncation of the FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. This makes the parallel FDTD algorithm easier to implement. The parallel performance with different number of processors is illustrated for one rough surface realization and shows that the computation time of our parallel FDTD algorithm is dramatically reduced relative to a single-processor implementation. Finally, the composite scattering coefficients versus scattered and azimuthal angle are presented and analyzed for different conditions, including the surface roughness, the dielectric constants, the polarization, and the size of the 3-D object.

  16. Spatially resolved Thomson scattering measurements of the transition from the collective to the non-collective regime in a laser-produced plasma

    Science.gov (United States)

    Schaeffer, D. B.; Constantin, C. G.; Bondarenko, A. S.; Everson, E. T.; Niemann, C.

    2016-11-01

    We present optical Thomson scattering results that image for the first time in a single measurement the spatial transition from collective to non-collective scattering. Data were taken in the Phoenix laser laboratory at the University of California, Los Angeles. The Raptor laser was used to ablate a carbon plasma, which was diagnosed with the frequency-doubled Phoenix laser serving as a Thomson scattering probe. Scattered light was collected from the laser plasma up to 10 cm from the target surface and up to 10 us after ablation, and imaged with high spatial and spectral resolutions. The results show a strong Thomson collective feature close to the target surface that smoothly transitions to a non-collective feature over several mm.

  17. Acoustic phonon-limited resistivity of spin-orbit coupled two-dimensional electron gas: the deformation potential and piezoelectric scattering.

    Science.gov (United States)

    Biswas, Tutul; Ghosh, Tarun Kanti

    2013-01-23

    We study the interaction between electron and acoustic phonons in a Rashba spin-orbit coupled two-dimensional electron gas using Boltzmann transport theory. Both the deformation potential and piezoelectric scattering mechanisms are considered in the Bloch-Grüneisen (BG) regime as well as in the equipartition (EP) regime. The effect of the Rashba spin-orbit interaction on the temperature dependence of the resistivity in the BG and EP regimes is discussed. We find that the effective exponent of the temperature dependence of the resistivity in the BG regime decreases due to spin-orbit coupling.

  18. Evidence for out-of-equilibrium states in warm dense matter probed by X-ray Thomson scattering

    CERN Document Server

    Clerouin, J; Robert, G; Ticknor, C; Kress, J; Collins, L

    2014-01-01

    A recent and unexpected discrepancy between \\textit{ab initio} simulations and the interpretation of a laser shock experiment on aluminum, probed by X-ray Thomson scattering (XRTS), is addressed. The ion-ion structure factor deduced from the XRTS elastic peak (ion feature) is only compatible with a strongly coupled out-of-equilibrium state. Orbital free molecular dynamics simulations with ions colder than the electrons are employed to interpret the experiment. The relevance of decoupled temperatures for ions and electrons is discussed. The possibility that it mimics a transient, or metastable, out-of-equilibrium state after melting is also suggested.

  19. Determination of the normalized surface height autocorrelation function of a two-dimensional randomly rough dielectric surface by the inversion of light scattering data

    CERN Document Server

    Simonsen, Ingve; Kryvi, Jacob B; Maradudin, Alexei A

    2015-01-01

    An expression is obtained on the basis of phase perturbation theory for the contribution to the mean differential reflection coefficient from the in-plane co-polarized component of the light scattered diffusely from a two-dimensional randomly rough dielectric surface when the latter is illuminated by s-polarized light. This result forms the basis for an approach to inverting experimental light scattering data to obtain the normalized surface height autocorrelation function of the surface. Several parametrized forms of this correlation function, and the minimization of a cost function with respect to the parameters defining these representations, are used in the inversion scheme. This approach also yields the rms height of the surface roughness, and the dielectric constant of the dielectric substrate if it is not known in advance. The input data used in validating this inversion consists of computer simulation results for surfaces defined by exponential and Gaussian surface height correlation functions, withou...

  20. Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S G; Barty, C P J; Betts, S M; Brown, W J; Crane, J K; Cross, R R; Fittinghoff, D N; Gibson, D J; Hartemann, F V; Kuba, J; LaSage, G P; Rosenzweig, J B; Slaughter, D R; Springer, P T; Tremaine, A M

    2003-07-01

    We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10{sup 20} photons/s/0.1% bandwidth/mm{sup 2}/mrad{sup 2}. Initial results are reported and compared to theoretical calculations.

  1. Generation of bright attosecond x-ray pulse trains via Thomson scattering from laser-plasma accelerators.

    Science.gov (United States)

    Luo, W; Yu, T P; Chen, M; Song, Y M; Zhu, Z C; Ma, Y Y; Zhuo, H B

    2014-12-29

    Generation of attosecond x-ray pulse attracts more and more attention within the advanced light source user community due to its potentially wide applications. Here we propose an all-optical scheme to generate bright, attosecond hard x-ray pulse trains by Thomson backscattering of similarly structured electron beams produced in a vacuum channel by a tightly focused laser pulse. Design parameters for a proof-of-concept experiment are presented and demonstrated by using a particle-in-cell code and a four-dimensional laser-Compton scattering simulation code to model both the laser-based electron acceleration and Thomson scattering processes. Trains of 200 attosecond duration hard x-ray pulses holding stable longitudinal spacing with photon energies approaching 50 keV and maximum achievable peak brightness up to 1020 photons/s/mm2/mrad2/0.1%BW for each micro-bunch are observed. The suggested physical scheme for attosecond x-ray pulse trains generation may directly access the fastest time scales relevant to electron dynamics in atoms, molecules and materials.

  2. Development of a Thomson scattering system and its use in a rotating magnetic field driven field-reversed configurations plasma

    Science.gov (United States)

    Lee, Kiyong

    The Thomson scattering system has been utilized on the Translation Confinement & Sustainment Upgrade (TCSU) experiment to measure the electron temperature and density. The system uses five polychromators from General Atomics attached with three pre-amplifier modules from Princeton Plasma Physics Laboratory to measure five spatial points during a single plasma discharge. The diagnostic consisting of various mechanical and optical components is introduced, followed by the calibration procedure of the system. For validating measurements, the electron temperature and the relative density obtained from Thomson scattering are compared with measurements from the Langmuir probe. Both measurements are in good agreement. A power scan was conducted by applying different voltages to the rotating magnetic field (RMF) current drive to observe the scaling properties of temperature and density for even-parity and odd-parity RMF operations. Also, a discrepancy is observed when comparing the density based on pressure-balance with localized measurements. Further analysis indicates a possibility of an ion-temperature-gradient, presumably due to ion cyclotron heating, present during steady-state operation.

  3. Determination of the normalized surface height autocorrelation function of a two-dimensional randomly rough dielectric surface by the inversion of light scattering data in p-polarization

    Science.gov (United States)

    Kryvi, J. B.; Simonsen, I.; Maradudin, A. A.

    2016-09-01

    The contribution to the mean differential reflection coefficient from the in-plane, co-polarized scattering of p- polarized light from a two-dimensional randomly rough dielectric surface is used to invert scattering data to obtain the normalized surface height autocorrelation function of the surface. Within phase perturbation theory this contribution to the mean differential reflection coefficient possesses singularities (poles) when the polar scattering angle θs equals +/-θB= +/- tan-1√E, where E is the dielectric constant of the dielectric medium and θB is the Brewster angle. Nevertheless, we show in this paper that if the mean differential reflection coefficient is measured only in the angular range |θs| inversion scheme. This approach also yields the rms height of the surface roughness, and the dielectric constant of the scattering medium if it is not known in advance. The input data used in this minimization procedure consist of computer simulation results for surfaces defined by exponential and Gaussian surface height correlation functions, without and with the addition of multiplicative noise. The proposed inversion scheme is computationally efficient.

  4. Simulating x-ray Thomson scattering signals from high-density, millimetre-scale plasmas at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, D. A., E-mail: david.chapman@awe.co.uk [Plasma Physics Group, Radiation Physics Department, AWE plc, Reading RG7 4PR (United Kingdom); Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom); Kraus, D.; Falcone, R. W. [Department of Physics, University of California, Berkeley, California 94720 (United States); Kritcher, A. L.; Bachmann, B.; Collins, G. W.; Gaffney, J. A.; Hawreliak, J. A.; Landen, O. L.; Le Pape, S.; Ma, T.; Nilsen, J.; Pak, A.; Swift, D. C.; Döppner, T. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Gericke, D. O. [Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom); Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94309 (United States); Guymer, T. M. [Plasma Physics Group, Radiation Physics Department, AWE plc, Reading RG7 4PR (United Kingdom); Neumayer, P. [Gesellschaft für Schwerionenforschung, 64291 Darmstadt (Germany); Redmer, R. [Institut für Physik, Universität Rostock, 18051 Rostock (Germany); and others

    2014-08-15

    We have developed a model for analysing x-ray Thomson scattering data from high-density, millimetre-scale inhomogeneous plasmas created during ultra-high pressure implosions at the National Ignition Facility in a spherically convergent geometry. The density weighting of the scattered signal and attenuation of the incident and scattered x-rays throughout the target are included using radial profiles of the density, opacity, ionization state, and temperature provided by radiation-hydrodynamics simulations. These simulations show that the scattered signal is strongly weighted toward the bulk of the shocked plasma and the Fermi degenerate material near the ablation front. We show that the scattered signal provides a good representation of the temperature of this highly nonuniform bulk plasma and can be determined to an accuracy of ca. 15% using typical data analysis techniques with simple 0D calculations. On the other hand, the mean ionization of the carbon in the bulk is underestimated. We suggest that this discrepancy is due to the convolution of scattering profiles from different regions of the target. Subsequently, we discuss modifications to the current platform to minimise the impact of inhomogeneities, as well as opacity, and also to enable probing of conditions more strongly weighted toward the compressed core.

  5. Tip-Enhanced Raman Scattering Imaging of Two-Dimensional Tungsten Disulfide with Optimized Tip Fabrication Process

    Science.gov (United States)

    Lee, Chanwoo; Kim, Sung Tae; Jeong, Byeong Geun; Yun, Seok Joon; Song, Young Jae; Lee, Young Hee; Park, Doo Jae; Jeong, Mun Seok

    2017-01-01

    We successfully achieve the tip-enhanced nano Raman scattering images of a tungsten disulfide monolayer with optimizing a fabrication method of gold nanotip by controlling the concentration of etchant in an electrochemical etching process. By applying a square-wave voltage supplied from an arbitrary waveform generator to a gold wire, which is immersed in a hydrochloric acid solution diluted with ethanol at various ratios, we find that both the conical angle and radius of curvature of the tip apex can be varied by changing the ratio of hydrochloric acid and ethanol. We also suggest a model to explain the origin of these variations in the tip shape. From the systematic study, we find an optimal condition for achieving the yield of ~60% with the radius of ~34 nm and the cone angle of ~35°. Using representative tips fabricated under the optimal etching condition, we demonstrate the tip-enhanced Raman scattering experiment of tungsten disulfide monolayer grown by a chemical vapor deposition method with a spatial resolution of ~40 nm and a Raman enhancement factor of ~4,760.

  6. Qualification of a high-efficiency, gated spectrometer for x-ray Thomson scattering on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Döppner, T.; Kritcher, A. L.; Bachmann, B.; Burns, S.; Hawreliak, J.; House, A.; Landen, O. L.; LePape, S.; Ma, T.; Pak, A.; Swift, D. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Neumayer, P. [Gesellschaft für Schwerionenphysik, 64291 Darmstadt (Germany); Kraus, D. [University of California, Berkeley, California 94720 (United States); Falcone, R. W. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94309 (United States)

    2014-11-15

    We have designed, built, and successfully fielded a highly efficient and gated Bragg crystal spectrometer for x-ray Thomson scattering measurements on the National Ignition Facility (NIF). It utilizes a cylindrically curved Highly Oriented Pyrolytic Graphite crystal. Its spectral range of 7.4–10 keV is optimized for scattering experiments using a Zn He-α x-ray probe at 9.0 keV or Mo K-shell line emission around 18 keV in second diffraction order. The spectrometer has been designed as a diagnostic instrument manipulator-based instrument for the NIF target chamber at the Lawrence Livermore National Laboratory, USA. Here, we report on details of the spectrometer snout, its novel debris shield configuration and an in situ spectral calibration experiment with a Brass foil target, which demonstrated a spectral resolution of E/ΔE = 220 at 9.8 keV.

  7. Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST)

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, C. M., E-mail: cjacobson@wisc.edu; Borchardt, M. T.; Den Hartog, D. J.; Falkowski, A. F.; Morton, L. A.; Thomas, M. A. [Department of Physics, University of Wisconsin–Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

    2016-11-15

    The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  9. Quantifying noise sources in the KSTAR 2014 Thomson Scattering system from the measured variation on electron temperature

    CERN Document Server

    Oh, Tae-suk; Lee, J H; Lee, S H; Scannell, R; Field, A R; Cho, K; Bawa'aneh, M S; Ghim, Y -c

    2015-01-01

    With the Thomson scattering (TS) system in KSTAR, temporal evolution of electron temperature ($T_e$) is estimated using a weighted look-up table method with fast sampling ($1.25$ or $2.5$ GS/s) digitizers during the 2014 KSTAR campaign. Background noise level is used as a weighting parameter without considering the photon noise due to the absence of information on absolute photon counts detected by the TS system. Estimated electron temperature during a relatively quiescent discharge are scattered, i.e., $15$\\% variation on $T_e$ with respect to its mean value. We find that this $15$\\% variation on $T_e$ cannot be explained solely by the background noise level which leads us to include photon noise effects in our analysis. Using synthetic data, we have estimated the required photon noise level consistent with the observation and determined the dominant noise source in KSTAR TS system.

  10. Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST)

    Science.gov (United States)

    Jacobson, C. M.; Borchardt, M. T.; Den Hartog, D. J.; Falkowski, A. F.; Morton, L. A.; Thomas, M. A.

    2016-11-01

    The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.

  11. Neutron scattering studies of two-dimensional antiferromagnetic spin fluctuations in insulating and superconducting S = ½ systems

    DEFF Research Database (Denmark)

    Christensen, Niels Bech

    polarized multimagnon excitations is discovered at energies above the single-magnon branch. At low energies, the findings are well described bylinear spin wave theory. At high energies, linear spin wave theory fails and instead the data are very well accounted for by state-of-the-art Quantum Monte Carlo......Time-of-flight and polarized triple axis neutron scattering is used to probe the spin excitations of Cu(DCOO)_2_·_4D_2O and La_2_-_xSr_xCuO_4. The first part of the thesis contains an investigation of the excitation spectrum of the square lattice S = 1/2Heisenberg antiferromagnet Cu(DCOO)_2_·_4D_2O...

  12. In situ analysis of size distribution of nano-particles in reactive plasmas using two dimensional laser light scattering method

    Science.gov (United States)

    Kamataki, K.; Morita, Y.; Shiratani, M.; Koga, K.; Uchida, G.; Itagaki, N.

    2012-04-01

    We have developed a simple in-situ method for measuring the size distribution (the mean size (mean diameter) and size dispersion) of nano-particles generated in reactive plasmas using the 2 dimensional laser light scattering (2DLLS) method. The principle of the method is based on thermal coagulation of the nano-particles, which occurs after the discharge is turned off, and the size and density of the nano-particles can then be deduced. We first determined the 2D spatial distribution of the density and size of the nano-particles in smaller particle size (a few nm) range than ones deduced from the conventional 2DLLS method. From this 2D dataset, we have for the first time been able to determine the size distribution of nano-particles generated in a reactive plasma without ex-situ measurements.

  13. Multiple-scattering theory for out-of-plane propagation of elastic waves in two-dimensional phononic crystals.

    Science.gov (United States)

    Mei, Jun; Liu, Zhengyou; Qiu, Chunyin

    2005-06-29

    We extend the multiple-scattering theory (MST) to out-of-plane propagating elastic waves in 2D periodical composites by taking into account the full vector character. The formalism for both the band structure calculation and the reflection and transmission coefficient calculation for finite slabs is presented. The latter is based on a double-layer scheme, which obtains the reflection and transmission matrix elements for the multilayer slab from those of a single layer. Being more rapid in both the band structure and the transmission coefficient calculations for out-of-plane propagating elastic waves, our approach especially shows great advantages in handling the systems with mixed solid and fluid components, for which the conventional plane wave approach fails. As the applications of the formalism, we calculate the band structure as well as the transmission coefficients through finite slabs for systems with lead rods in an epoxy host, steel rods in a water host and water rods in a PMMA host.

  14. Neutron scattering studies of two-dimensional antiferromagnetic spin fluctuations in insulating and superconducting S = 1/2 systems

    Energy Technology Data Exchange (ETDEWEB)

    Bech Christensen, N

    2005-01-01

    Time-of-flight and polarized triple axis neutron scattering is used to probe the spin excitations of Cu(DCOO){sub 2}x4D{sub 2}O and La{sub 2-x}Sr{sub x}CuO{sub 4}. The first part of the thesis contains an investigation of the excitation spectrum of the square lattice S = 1/2 Heisenberg antiferromagnet Cu(DCOO){sub 2}4D{sub 2}O. Along the antiferromagnetic zone boundary a pronounced intensity variation is found for the dominant single-magnon excitations. This variation tracks an already known zone boundary dispersion. Using polarization analysis to separate the components of the excitation spectrum, a continuum of longitudinally polarized multimagnon excitations is discovered at energies above the single-magnon branch. At low energies, the findings are well described by linear spin wave theory. At high energies, linear spin wave theory fails and instead the data are very well accounted for by state-of-the-art Quantum Monte Carlo computations. In the second part of the thesis, the spin excitation spectra of the high temperature superconductors La{sub 1.90}Sr{sub 0.10}CuO{sub 4} and La{sub 1.84}Sr{sub 0.16}Cu characterized. The main discovery is that the excitations are dispersive at both doping levels. The dispersion strongly resembles that seen in other high-T{sub c} superconductors. The presence of dispersive excitations does not require superconductivity to exist. For La{sub 1.84}Sr{sub 0.16}CuO{sub 4}, but not for La{sub 1.90}Sr{sub 0.10}CuO{sub 4}, the onset superconductivity gives rise to a spectral weight shift which displays qualitative and quantitative similarities to the resonance mode observed in other high-T{sub c} superconductors. (au)

  15. Generalized two-dimensional (2D) linear system analysis metrics (GMTF, GDQE) for digital radiography systems including the effect of focal spot, magnification, scatter, and detector characteristics

    Science.gov (United States)

    Kuhls-Gilcrist, Andrew T.; Gupta, Sandesh K.; Bednarek, Daniel R.; Rudin, Stephen

    2010-01-01

    The MTF, NNPS, and DQE are standard linear system metrics used to characterize intrinsic detector performance. To evaluate total system performance for actual clinical conditions, generalized linear system metrics (GMTF, GNNPS and GDQE) that include the effect of the focal spot distribution, scattered radiation, and geometric unsharpness are more meaningful and appropriate. In this study, a two-dimensional (2D) generalized linear system analysis was carried out for a standard flat panel detector (FPD) (194-micron pixel pitch and 600-micron thick CsI) and a newly-developed, high-resolution, micro-angiographic fluoroscope (MAF) (35-micron pixel pitch and 300-micron thick CsI). Realistic clinical parameters and x-ray spectra were used. The 2D detector MTFs were calculated using the new Noise Response method and slanted edge method and 2D focal spot distribution measurements were done using a pin-hole assembly. The scatter fraction, generated for a uniform head equivalent phantom, was measured and the scatter MTF was simulated with a theoretical model. Different magnifications and scatter fractions were used to estimate the 2D GMTF, GNNPS and GDQE for both detectors. Results show spatial non-isotropy for the 2D generalized metrics which provide a quantitative description of the performance of the complete imaging system for both detectors. This generalized analysis demonstrated that the MAF and FPD have similar capabilities at lower spatial frequencies, but that the MAF has superior performance over the FPD at higher frequencies even when considering focal spot blurring and scatter. This 2D generalized performance analysis is a valuable tool to evaluate total system capabilities and to enable optimized design for specific imaging tasks. PMID:21243038

  16. Sensitivity kernels for coda-wave interferometry and scattering tomography: theory and numerical evaluation in two-dimensional anisotropically scattering media

    Science.gov (United States)

    Margerin, Ludovic; Planès, Thomas; Mayor, Jessie; Calvet, Marie

    2016-01-01

    Coda-wave interferometry is a technique which exploits tiny waveform changes in the coda to detect temporal variations of seismic properties in evolving media. Observed waveform changes are of two kinds: traveltime perturbations and distortion of seismograms. In the last 10 yr, various theories have been published to relate either background velocity changes to traveltime perturbations, or changes in the scattering properties of the medium to waveform decorrelation. These theories have been limited by assumptions pertaining to the scattering process itself-in particular isotropic scattering, or to the propagation regime-single-scattering and/or diffusion. In this manuscript, we unify and extend previous results from the literature using a radiative transfer approach. This theory allows us to incorporate the effect of anisotropic scattering and to cover a broad range of propagation regimes, including the contribution of coherent, singly scattered and multiply scattered waves. Using basic physical reasoning, we show that two different sensitivity kernels are required to describe traveltime perturbations and waveform decorrelation, respectively, a distinction which has not been well appreciated so far. Previous results from the literature are recovered as limiting cases of our general approach. To evaluate numerically the sensitivity functions, we introduce an improved version of a spectral technique known as the method of `rotated coordinate frames', which allows global evaluation of the Green's function of the radiative transfer equation in a finite domain. The method is validated through direct pointwise comparison with Green's functions obtained by the Monte Carlo method. To illustrate the theory, we consider a series of scattering media displaying increasing levels of scattering anisotropy and discuss the impact on the traveltime and decorrelation kernels. We also consider the related problem of imaging variations of scattering properties based on intensity

  17. Upgrade of the automatic analysis system in the TJ-II Thomson Scattering diagnostic: New image recognition classifier and fault condition detection

    NARCIS (Netherlands)

    Makili, L.; Vega, J.; Dormido-Canto, S.; Pastor, I.; Pereira, A.; Farias, G.; Portas, A.; Perez-Risco, D.; Rodriguez-Fernandez, M. C.; Busch, P.

    2010-01-01

    An automatic image classification system based on support vector machines (SVM) has been in operation for years in the TJ-II Thomson Scattering diagnostic. It recognizes five different types of images: CCD camera background, measurement of stray light without plasma or in a collapsed discharge, imag

  18. High-transmission 20-channel polychromator for observing non-Maxwellian electron velocity distributions in plasmas by Thomson scattering.

    Science.gov (United States)

    Barth, C J

    1988-07-15

    A high-transmission (~45%) twenty-channel polychromator equipped with near-infrared sensitive photomultipliers has been constructed to record Thomson scattering spectra at the TORTUR tokamak. The high transmission was achieved by the use of mirrors instead of fiber optics to guide the spectrally resolved light to a set of photomultipliers. Spectral analysis is performed with a holographically ruled concave grating. Acceptable dimensions of the wavelength selection mirrors were obtained by magnifying the spectral image by a factor of 5 with a Mangin mirror. Electron temperatures up to 1000 eV at a density of 5 x 10(19) m(-3) can be measured with an accuracy of approximately l%. Both high sensitivity and high resolution enable the detection of irregularities in the velocity distribution. For example, satellites corresponding to partial densities of (5 +/- 1) x 10(17) m(-3) were found at 23 nm from the laser wavelength.

  19. 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...

  20. Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Döppner, T., E-mail: doeppner1@llnl.gov; Bachmann, B.; Emig, J.; Hardy, M.; Kalantar, D. H.; Kritcher, A. L.; Landen, O. L.; Ma, T.; Wood, R. D. [Lawrence Livermore National Laboratory, Livermore, California 94720 (United States); Kraus, D.; Saunders, A. M. [University of California, Berkeley, California 94720 (United States); Neumayer, P. [Gesellschaft für Schwerionenphysik, Darmstadt (Germany); Falcone, R. W. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Fletcher, L. B. [SLAC National Accelerator Laboratory, Menlo Park, California 94720 (United States)

    2016-11-15

    We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5–10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)]. Here we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction. Such high photon energy line emission will be required to penetrate and probe ultra-high-density plasmas or plasmas of mid-Z elements.

  1. Operation and beam profiling of an up to 200 kHz pulse-burst laser for Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Young, W. C., E-mail: wcyoung2@wisc.edu; Den Hartog, D. J. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2014-11-15

    A new, high-repetition rate laser is in development for use on the Thomson scattering diagnostic on the Madison Symmetric Torus. The laser has been tested at a rate of 200 kHz in a pulse-burst operation, producing bursts of 5 pulses above 1.5 J each, while capable of bursts of 17 pulses at 100 kHz. A master oscillator-power amplifier architecture is used with a Nd:YVO{sub 4} oscillator, four Nd:YAG amplifiers, and a Nd:glass amplifier. A radial profile over the pulse sequence is measured by using a set of graphite apertures and an energy meter, showing a change in beam quality over a pulsing sequence.

  2. Interaction of relativistic electrons with an intense laser pulse: High-order harmonic generation based on Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hack, Szabolcs [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Department of Theoretical Physics, University of Szeged, Tisza L. krt. 84-86, H-6720 Szeged (Hungary); Varró, Sándor [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Wigner Research Center for Physics, SZFI, PO Box 49, H-1525 Budapest (Hungary); Czirják, Attila [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Department of Theoretical Physics, University of Szeged, Tisza L. krt. 84-86, H-6720 Szeged (Hungary)

    2016-02-15

    We investigate nonlinear Thomson scattering as a source of high-order harmonic radiation with the potential to enable attosecond light pulse generation. We present a new analytic solution of the electron’s relativistic equations of motion in the case of a short laser pulse with a sine-squared envelope. Based on the single electron emission, we compute and analyze the radiated amplitude and phase spectrum for a realistic electron bunch, with special attention to the correct initial values. These results show that the radiation spectrum of an electron bunch in head-on collision with a sufficiently strong laser pulse of sine-squared envelope has a smooth frequency dependence to allow for the synthesis of attosecond light pulses.

  3. LIGHT SOURCE: RF deflecting cavity for bunch length measurement in Tsinghua Thomson scattering X-ray source

    Science.gov (United States)

    Shi, Jia-Ru; Chen, Huai-Bi; Tang, Chuan-Xiang; Huang, Wen-Hui; Du, Ying-Chao; Zheng, Shu-Xin; Ren, Li

    2009-06-01

    An RF deflecting cavity used for bunch length measurement has been designed and fabricated at Tsinghua University for the Thomson Scattering X-Ray Source. The cavity is a 2856 MHz, π-mode, 3-cell standing-wave cavity, to diagnose the 3.5 MeV beam produced by photocathode electron gun. With a larger power source, the same cavity will again be used to measure the accelerated beam with energy of 50 MeV before colliding with the laser pulse. The RF design using MAFIA for both the cavity shape and the power coupler is reviewed, followed by presenting the fabrication procedure and bench measurement results of two cavities.

  4. Simultaneous measurement of electron and heavy particle temperatures in He laser-induced plasma by Thomson and Rayleigh scattering

    Energy Technology Data Exchange (ETDEWEB)

    Dzierzega, K.; Mendys, A.; Zawadzki, W. [Marian Smoluchowski Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland); Pokrzywka, B. [Mt. Suhora Observatory, Pedagogical University of Cracow, ul. Podchorazych 2, 30-084 Krakow (Poland); Pellerin, S. [GREMI, site de Bourges, Universite d' Orleans, CNRS, rue Gaston Berger BP 4043, 18028 Bourges (France)

    2013-04-01

    Thomson and Rayleigh scattering methods were applied to quantify the electron and heavy particle temperatures, as well as electron number density, in a laser spark in helium at atmospheric pressure. Plasma was created using 4.5 ns, 25 mJ pulses from Nd:YAG laser at 532 nm. Measurements, performed for the time interval between 20 ns and 800 ns after breakdown, show electron density and temperature to decrease from 7.8 Multiplication-Sign 10{sup 23} m{sup -3} to 2.6 Multiplication-Sign 10{sup 22} m{sup -3} and from 95 900 K to 10 350 K, respectively. At the same time, the heavy particle temperature drops from only 47 000 K down to 4100 K which indicates a two temperature plasma out of local isothermal equilibrium.

  5. Solution of two-dimensional electromagnetic scattering problem by FDTD with optimal step size, based on a semi-norm analysis

    Energy Technology Data Exchange (ETDEWEB)

    Monsefi, Farid [Division of Applied Mathematics, The School of Education, Culture and Communication, Mälardalen University, MDH, Västerås, Sweden and School of Innovation, Design and Engineering, IDT, Mälardalen University, MDH Väs (Sweden); Carlsson, Linus; Silvestrov, Sergei [Division of Applied Mathematics, The School of Education, Culture and Communication, Mälardalen University, MDH, Västerås (Sweden); Rančić, Milica [Division of Applied Mathematics, The School of Education, Culture and Communication, Mälardalen University, MDH, Västerås, Sweden and Department of Theoretical Electrical Engineering, Faculty of Electronic Engineering, University (Serbia); Otterskog, Magnus [School of Innovation, Design and Engineering, IDT, Mälardalen University, MDH Västerås (Sweden)

    2014-12-10

    To solve the electromagnetic scattering problem in two dimensions, the Finite Difference Time Domain (FDTD) method is used. The order of convergence of the FDTD algorithm, solving the two-dimensional Maxwell’s curl equations, is estimated in two different computer implementations: with and without an obstacle in the numerical domain of the FDTD scheme. This constitutes an electromagnetic scattering problem where a lumped sinusoidal current source, as a source of electromagnetic radiation, is included inside the boundary. Confined within the boundary, a specific kind of Absorbing Boundary Condition (ABC) is chosen and the outside of the boundary is in form of a Perfect Electric Conducting (PEC) surface. Inserted in the computer implementation, a semi-norm has been applied to compare different step sizes in the FDTD scheme. First, the domain of the problem is chosen to be the free-space without any obstacles. In the second part of the computer implementations, a PEC surface is included as the obstacle. The numerical instability of the algorithms can be rather easily avoided with respect to the Courant stability condition, which is frequently used in applying the general FDTD algorithm.

  6. Demonstration of space-resolved x-ray Thomson scattering capability for warm dense matter experiments on the Z accelerator

    Science.gov (United States)

    Ao, T.; Harding, E. C.; Bailey, J. E.; Lemke, R. W.; Desjarlais, M. P.; Hansen, S. B.; Smith, I. C.; Geissel, M.; Maurer, A.; Reneker, J.; Romero, D.; Sinars, D. B.; Rochau, G. A.; Benage, J. F.

    2016-03-01

    Experiments on the Sandia Z pulsed-power accelerator have demonstrated the ability to produce warm dense matter (WDM) states with unprecedented uniformity, duration, and size, which are ideal for investigations of fundamental WDM properties. For the first time, space-resolved x-ray Thomson scattering (XRTS) spectra from shocked carbon foams were recorded on Z. The large (>20 MA) electrical current produced by Z was used to launch Al flyer plates up to 25 km/s. The impact of the flyer plate on a CH2 foam target produced a shocked state with an estimated pressure of 0.75 Mbar, density of 0.52 g/cm3, and temperature of 4.3 eV. Both unshocked and shocked portions of the foam target were probed with 6.2 keV x-rays produced by focusing the Z-Beamlet laser onto a nearby Mn foil. The data are composed of three spatially distinct spectra that were simultaneously captured with a single spectrometer with high spectral (4.8 eV) and spatial (190 μm) resolutions. Detailed spectral information from three target locations is provided simultaneously: the incident x-ray source, the scattered signal from unshocked foam, and the scattered signal from shocked foam.

  7. Design and Operation of a Frequency Doubled Nd:YAG Thomson Scattering System with Transmission Grating ICCD Spectrometer

    Science.gov (United States)

    Schoenbeck, N. L.; Dowd, A. S.; Fonck, R. J.; Schlossberg, D. J.; Winz, G. R.

    2012-10-01

    A novel Thomson scattering system has been deployed on the Pegasus Toroidal Experiment. It provides a relatively low-cost, simplified design. Scattering is achieved using a 7 ns, 2 J frequency doubled Nd:YAG laser operating at 532 nm. The laser focuses to ˜3 mm diameter within the plasma via a 7 m beam-line. The beam-line contains cameras as beam finders and remotely adjustable mirrors for shot-to-shot alignment. A custom multi-element lens collects scattered photons from 15 cm 40%) image intensified CCD (ICCD) camera. Three spectrometers provide a total of 24 channels. Two interchangeable gratings exist to cover low (Te = 10--100 eV) and high (Te = 0.10--1 keV) electron temperature regimes on Pegasus. The spectrometer is optimized for ne from mid-10^18 to mid-10^19 m-3. The signal-to-noise expected is ˜0.5 of an equivalent system using Nd:YAG at 1064 nm and avalanche photodiode detectors.

  8. Automated classification of single airborne particles from two-dimensional angle-resolved optical scattering (TAOS) patterns by non-linear filtering

    Science.gov (United States)

    Crosta, Giovanni Franco; Pan, Yong-Le; Aptowicz, Kevin B.; Casati, Caterina; Pinnick, Ronald G.; Chang, Richard K.; Videen, Gorden W.

    2013-12-01

    Measurement of two-dimensional angle-resolved optical scattering (TAOS) patterns is an attractive technique for detecting and characterizing micron-sized airborne particles. In general, the interpretation of these patterns and the retrieval of the particle refractive index, shape or size alone, are difficult problems. By reformulating the problem in statistical learning terms, a solution is proposed herewith: rather than identifying airborne particles from their scattering patterns, TAOS patterns themselves are classified through a learning machine, where feature extraction interacts with multivariate statistical analysis. Feature extraction relies on spectrum enhancement, which includes the discrete cosine FOURIER transform and non-linear operations. Multivariate statistical analysis includes computation of the principal components and supervised training, based on the maximization of a suitable figure of merit. All algorithms have been combined together to analyze TAOS patterns, organize feature vectors, design classification experiments, carry out supervised training, assign unknown patterns to classes, and fuse information from different training and recognition experiments. The algorithms have been tested on a data set with more than 3000 TAOS patterns. The parameters that control the algorithms at different stages have been allowed to vary within suitable bounds and are optimized to some extent. Classification has been targeted at discriminating aerosolized Bacillus subtilis particles, a simulant of anthrax, from atmospheric aerosol particles and interfering particles, like diesel soot. By assuming that all training and recognition patterns come from the respective reference materials only, the most satisfactory classification result corresponds to 20% false negatives from B. subtilis particles and classification method may be adapted into a real-time operation technique, capable of detecting and characterizing micron-sized airborne particles.

  9. Use of webcams as tools for alignment and supervision of a Thomson scattering system in the near infrared

    Energy Technology Data Exchange (ETDEWEB)

    Andrebe, Y., E-mail: yanis.andrebe@epfl.ch [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, Station 13, 1015 Lausanne (Switzerland); Behn, R.; Duval, B.P.; Etienne, P.; Pitzschke, A. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, Station 13, 1015 Lausanne (Switzerland)

    2011-10-15

    The alignment stability is a major concern for Thomson scattering systems. Even small angular deviations of the laser beams crossing the plasma lead to a loss of the calibration resulting in unreliable measurements of the electron density profile. For the TCV (Tokamak a Configuration Variable) installation, the beam paths from the laser output to the vacuum chamber are {approx}25 m long and include several optical components. In order to monitor the alignment on a regular basis, a set of 9 cameras has been installed at several locations along the beam path. They view the actual laser beam pattern by recording the scattered light from an intercepting optical surface (mirror or window) together with the position of markers used for reference. Small 'webcams' are used for this purpose; they feature adequate intensity response at the laser wavelength of 1.06 {mu}m, are compact, cheap and several units may be connected to a server PC simultaneously. The real-time images from all the cameras are accessible from a Web browser. This installation has proven to be extremely useful in the early detection of alignment problems and to assist the alignment procedure .

  10. 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...

  11. Measurement of electron density of the plasma in the Tokamak TCABR, through Thomson scattering diagnostic; Medida da densidade eletronica do plasma no Tokamak TCABR, atraves do diagnostico Espalhamento Thomson

    Energy Technology Data Exchange (ETDEWEB)

    Jeronimo, Leonardo Cunha

    2013-07-01

    Over the last few years is remarkable, so increasingly evident the need for a new source of energy for mankind. One promising option is through nuclear fusion, where the plasma produced in the reactor can be converted into electrical energy. Therefore, knowing the characteristics of this plasma is very important to control it and understand it so desirable. One of the diagnostic options is called Thomson scattering . This is considered the most reliable method for the determination of important plasma parameters such as temperature and electron density, and may also help in the study and explanation of various internal mechanisms. The great advantage lies in the tact that they consist of a direct measurement and nonperturbative. But it is a diagnosis whose installation and execution is admittedly complex, limiting it only a few laboratories in the fíeld of fusion for the world. Among the main difficulties, wc can highlight the fact that the scattered signal is very small, thus requiring a large increase of the incident power. Moreover, the external physical conditions can cause mechanical vibrations that eliminate or minimize them as much as possible, is a great challenge, considering the optical micrometrically very sensitive and needs involved in the system. This work describes the entire process of installation and operation of Thomson scattering diagnostic in tokamak TCABR and through this diagnosis, we work on results of electron temperature, to finally be able to calculate the electron density of the plasma. (author)

  12. Investigation of thermodynamic equilibrium in laser-induced aluminum plasma using the H{sub α} line profiles and Thomson scattering spectra

    Energy Technology Data Exchange (ETDEWEB)

    Cvejić, M., E-mail: marko.cvejic@ipb.ac.rs, E-mail: krzysztof.dzierzega@uj.edu.pl [Institute of Physics, University of Belgrade, P.O. Box 68, 11080 Belgrade (Serbia); Faculty of Physics, Weizmann Institute of Science, Rehovot 7610001 (Israel); Dzierżęga, K., E-mail: marko.cvejic@ipb.ac.rs, E-mail: krzysztof.dzierzega@uj.edu.pl; Pięta, T. [M. Smoluchowski Institute of Physics, Jagellonian University, ul. Łojasiewicza 11, 30-348 Kraków (Poland)

    2015-07-13

    We have studied isothermal equilibrium in the laser-induced plasma from aluminum pellets in argon at pressure of 200 mbar by using a method which combines the standard laser Thomson scattering and analysis of the H{sub α}, Stark-broadened, line profiles. Plasma was created using 4.5 ns, 4 mJ pulses from a Nd:YAG laser at 1064 nm. While electron density and temperature were determined from the electron feature of Thomson scattering spectra, the heavy particle temperature was obtained from the H{sub α} full profile applying computer simulation including ion-dynamical effects. We have found strong imbalance between these two temperatures during entire plasma evolution which indicates its non-isothermal character. At the same time, according to the McWhirter criterion, the electron density was high enough to establish plasma in local thermodynamic equilibrium.

  13. Neutron scattering study of Rb2Cu1-xCoxF4: A two-dimensional randomly ferromagnet-antiferromagnet

    DEFF Research Database (Denmark)

    Schins, A.G.; Nielsen, M.; Arts, A.F.M.

    1992-01-01

    A neutron scattering study of the magnetic order in the randomly mixed two-dimensional ferromagnet-antiferromagnet Rb2Cu1-xCoxF4 has been performed. For x = 0.037, 0.083, and 0.88, the system enters an oblique ferromagnetic phase, an axial ferromagnetic, and an axial antiferromagnetic phase...

  14. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic.

    Science.gov (United States)

    Swadling, G F; Ross, J S; Datte, P; Moody, J; Divol, L; Jones, O; Landen, O

    2016-11-01

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ∼8 J cm(-2). This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 10(19) cm(-2) Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

  15. An Improved Detector Electronics and Data Acquisition System Design for Thomson Scattering Diagnostic on DIII-D

    Science.gov (United States)

    Liu, C.

    2005-10-01

    The detector electronics and data acquisition system for the Thomson scattering diagnostic on DIII-D is being upgraded to replace the present CAMAC-based system. Besides more modern electronics, the proposed design contains a number of improved features. For instance, to reduce the gain drift with temperature in the avalanche photodiode, the diode will be mounted on a thermally insulated copper block and maintained at an elevated temperature using feedback control. Since the plasma background light plays a dominant role in the measurement noise, a model is used to analyze the noise contribution in regard to the time widths of the electronic output pulse and the signal integration gate. The building blocks of the detector electronics are GHz OpAmps and the ns analog switches. The method of differential gating [1] is used to cancel the charge injection induced by the high speed operation in the analog switch. 0.5em [1] X. Wang, AIP Conf. Proceeding 333, Beam Instrumentation Workshop, Vancouver, Canada (1994).

  16. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic

    Science.gov (United States)

    Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O.

    2016-11-01

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ˜8 J cm-2. This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 1019 cm-2 Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

  17. Customizable electron beams from optically controlled laser plasma acceleration for γ-ray sources based on inverse Thomson scattering

    Science.gov (United States)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Shadwick, B. A.

    2016-09-01

    Laser wakefield acceleration of electrons in the blowout regime can be controlled by tailoring the laser pulse phase and the plasma target. The 100 nm-scale bandwidth and negative frequency chirp of the optical driver compensate for the nonlinear frequency red-shift imparted by wakefield excitation. This mitigates pulse self-steepening and suppresses continuous injection. The plasma channel suppresses diffraction of the pulse leading edge, further reducing self-steepening, making injection even quieter. Besides, the channel destabilizes the pulse tail confined within the accelerator cavity (the electron density "bubble"), causing oscillations in the bubble size. The resulting periodic injection generates background-free comb-like beams - sequences of synchronized, low phase-space volume bunches. Controlling the number of bunches, their energy, and energy spacing by varying the channel radius and the pulse length (as permitted by the large bandwidth) enables the design of a tunable, all-optical source of polychromatic, pulsed γ-rays using the mechanism of inverse Thomson scattering. Such source may radiate ~107 quasi-monochromatic 10 MeV-scale photons per shot into a microsteradian-scale observation angle. The photon energy is distributed among several distinct bands, each having sub-25% energy spread dictated by the mrad-scale divergence of electron beam.

  18. Nonlinear coherent Thomson scattering from relativistic electron sheets as a means to produce isolated ultrabright attosecond x-ray pulses

    Directory of Open Access Journals (Sweden)

    H.-C. Wu (武慧春

    2011-07-01

    Full Text Available A new way to generate intense attosecond x-ray pulses is discussed. It relies on coherent Thomson scattering (CTS from relativistic electron sheets. A double layer technique is used to generate planar solid-density sheets of monochromatic high-γ electrons with zero transverse momentum such that coherently backscattered light is frequency upshifted by factors up to 4γ^{2}. Here previous work [H.-C. Wu et al., Phys. Rev. Lett. 104, 234801 (2010PRLTAO0031-900710.1103/PhysRevLett.104.234801] is extended to the regime of high-intensity probe light with normalized amplitude a_{0}>1 leading to nonlinear CTS effects such as pulse contraction and steepening. The results are derived both by particle-in-cell (PIC simulation in a boosted frame and by analytic theory. PIC simulation shows that powerful x-ray pulses (1 keV, 10   gigawatt can be generated. They call for experimental verification. Required prerequisites such as manufacture of nanometer-thick target foils is ready and ultrahigh contrast laser pulses should be within reach in the near future.

  19. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause “blanking” (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ∼8 J cm{sup −2}. This is significantly above the expected threshold for the onset of “blanking” effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate “blanking.” Estimates suggest that an areal density of 10{sup 19} cm{sup −2} Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

  20. Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system.

    Science.gov (United States)

    Tojo, H; Hatae, T; Hamano, T; Sakuma, T; Itami, K

    2013-09-01

    Collection optics for core measurements in a JT-60SA Thomson scattering system were designed. The collection optics will be installed in a limited space and have a wide field of view and wide wavelength range. Two types of the optics are therefore suggested: refraction and reflection types. The reflection system, with a large primary mirror, avoids large chromatic aberrations. Because the size limit of the primary mirror and vignetting due to the secondary mirror affect the total collection throughput, conditions that provide the high throughput are found through an optimization. A refraction system with four lenses forming an Ernostar system is also employed. The use of high-refractive-index glass materials enhances the freedom of the lens curvatures, resulting in suppression of the spherical and coma aberration. Moreover, sufficient throughput can be achieved, even with smaller lenses than that of a previous design given in [H. Tojo, T. Hatae, T. Sakuma, T. Hamano, K. Itami, Y. Aida, S. Suitoh, and D. Fujie, Rev. Sci. Instrum. 81, 10D539 (2010)]. The optical resolutions of the reflection and refraction systems are both sufficient for understanding the spatial structures in plasma. In particular, the spot sizes at the image of the optics are evaluated as ~0.3 mm and ~0.4 mm, respectively. The throughput for the two systems, including the pupil size and transmissivity, are also compared. The results show that good measurement accuracy (refraction system.

  1. Pair potentials for warm dense matter and their application to x-ray Thomson scattering in aluminum and beryllium

    Science.gov (United States)

    Harbour, L.; Dharma-wardana, M. W. C.; Klug, D. D.; Lewis, L. J.

    2016-11-01

    Ultrafast laser experiments yield increasingly reliable data on warm dense matter, but their interpretation requires theoretical models. We employ an efficient density functional neutral-pseudoatom hypernetted-chain (NPA-HNC) model with accuracy comparable to ab initio simulations and which provides first-principles pseudopotentials and pair potentials for warm-dense matter. It avoids the use of (i) ad hoc core-repulsion models and (ii) "Yukawa screening" and (iii) need not assume ion-electron thermal equilibrium. Computations of the x-ray Thomson scattering (XRTS) spectra of aluminum and beryllium are compared with recent experiments and with density-functional-theory molecular-dynamics (DFT-MD) simulations. The NPA-HNC structure factors, compressibilities, phonons, and conductivities agree closely with DFT-MD results, while Yukawa screening gives misleading results. The analysis of the XRTS data for two of the experiments, using two-temperature quasi-equilibrium models, is supported by calculations of their temperature relaxation times.

  2. 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....

  3. Validations of calibration-free measurements of electron temperature using double-pass Thomson scattering diagnostics from theoretical and experimental aspects

    Science.gov (United States)

    Tojo, H.; Yamada, I.; Yasuhara, R.; Ejiri, A.; Hiratsuka, J.; Togashi, H.; Yatsuka, E.; Hatae, T.; Funaba, H.; Hayashi, H.; Takase, Y.; Itami, K.

    2016-09-01

    This paper evaluates the accuracy of electron temperature measurements and relative transmissivities of double-pass Thomson scattering diagnostics. The electron temperature (Te) is obtained from the ratio of signals from a double-pass scattering system, then relative transmissivities are calculated from the measured Te and intensity of the signals. How accurate the values are depends on the electron temperature (Te) and scattering angle (θ), and therefore the accuracy of the values was evaluated experimentally using the Large Helical Device (LHD) and the Tokyo spherical tokamak-2 (TST-2). Analyzing the data from the TST-2 indicates that a high Te and a large scattering angle (θ) yield accurate values. Indeed, the errors for scattering angle θ = 135° are approximately half of those for θ = 115°. The method of determining the Te in a wide Te range spanning over two orders of magnitude (0.01-1.5 keV) was validated using the experimental results of the LHD and TST-2. A simple method to provide relative transmissivities, which include inputs from collection optics, vacuum window, optical fibers, and polychromators, is also presented. The relative errors were less than approximately 10%. Numerical simulations also indicate that the Te measurements are valid under harsh radiation conditions. This method to obtain Te can be considered for the design of Thomson scattering systems where there is high-performance plasma that generates harsh radiation environments.

  4. The Thomson Surface. II. Polarization

    CERN Document Server

    DeForest, C E; Tappin, S J

    2012-01-01

    The solar corona and heliosphere are visible via sunlight that is Thomson-scattered off of free electrons, yielding a radiance against the celestial sphere. In this second part of a three-article series, we discuss linear polarization of this scattered light parallel and perpendicular to the plane of scatter in the context of heliopheric imaging. The difference between these two radiances, (\\emph{pB}), varies quite differently with scattering angle, compared to the sum that would be detected by a nonpolarizing instrument (\\emph{B}). In particular, the Thomson surface defined by 90\\degr{} scattering angle is a local minimum in scattering efficiency for \\emph{B} measurements, but a local maximum in scattering efficiency for \\emph{pB} measurements. We describe the polarization properties of heliospheric Thomson scattered light and their applications, covering basic scattering physics, signal-to-noise considerations, measurement of 3-D object location, background subtraction, and modeled \\emph{pB} instrument resp...

  5. Final Report LDRD 02-ERD-013 Dense Plasma Characterization by X-ray Thomson Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Landen, O L; Glenzer, S H; Gregori, G; Pollaine, S M; Hammer, J H; Rogers, F; Meezan, N B; Chung, H; Lee, R W

    2005-02-11

    We have successfully demonstrated spectrally-resolved x-ray scattering in a variety of dense plasmas as a powerful new technique for providing microscopic dense plasma parameters unattainable by other means. The results have also been used to distinguish between ionization balance models. This has led to 10 published or to be published papers, 8 invited talks and significant interest from both internal and external experimental plasma physicists and the international statistical plasma physics theory community.

  6. COMPUTING THE CONTINUUM POLARIZATION FROM THOMSON SCATTERING IN GASEOUS CIRCUMSTELLAR DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Halonen, R. J.; Mackay, F. E.; Jones, C. E., E-mail: rhalonen@uwo.ca [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada)

    2013-01-15

    We investigate the computation of the intrinsic continuum linear polarization from electron scattering in optically thin and thick circumstellar disks of gas. We present the use of a non-LTE radiative transfer code, along with two different computational methods for obtaining the Stokes parameters, to reproduce the polarization levels that arise from disks of classical Be stars. Since the pioneering work of Poeckert and Marlborough, numerous improvements and refinements have been incorporated into computational radiative transfer models of classical Be stars. We present an assessment of the effect of several improvements on Poeckert and Marlborough's technique for calculating the polarization levels of the classical Be star {gamma} Cas. We find that improvements to the sampling of the disk density and the inclusion of a non-isothermal structure for the gas in the disk yield polarization levels that differ from the levels expected by Poeckert and Marlborough. Principally, the inclusion of the self-consistent calculation of the thermal structure of the disk has a significant impact on the resulting polarization. In addition, we assess the importance of the inclusion of multiple scattering calculations in predicting the continuum polarization in classical Be stars. We confirm that multiple scattering calculations are necessary for studying the linear polarization levels from optically thick gaseous disks around classical Be stars.

  7. Image processing methods for noise reduction in the TJ-II Thomson Scattering diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Dormido-Canto, S., E-mail: sebas@dia.uned.es [Departamento de Informatica y Automatica, UNED, Madrid 28040 (Spain); Farias, G. [Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Vega, J.; Pastor, I. [Asociacion EURATOM/CIEMAT para Fusion, Madrid 28040 (Spain)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We describe an approach in order to reduce or mitigate the stray-light on the images and show the exceptional results. Black-Right-Pointing-Pointer We analyze the parameters to take account in the proposed process. Black-Right-Pointing-Pointer We report a simplified exampled in order to explain the proposed process. - Abstract: The Thomsom Scattering diagnostic of the TJ-II stellarator provides temperature and density profiles. The CCD camera acquires images corrupted with noise that, in some cases, can produce unreliable profiles. The main source of noise is the so-called stray-light. In this paper we describe an approach that allows mitigation of the effects that stray-light has on the images: extraction regions with connected-components. In addition, the robustness and effectiveness of the noise reduction technique is validated in two ways: (1) supervised classification and (2) comparison of electron temperature profiles.

  8. Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system

    Energy Technology Data Exchange (ETDEWEB)

    Tojo, H.; Hatae, T.; Hamano, T.; Sakuma, T.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan)

    2013-09-15

    Collection optics for core measurements in a JT-60SA Thomson scattering system were designed. The collection optics will be installed in a limited space and have a wide field of view and wide wavelength range. Two types of the optics are therefore suggested: refraction and reflection types. The reflection system, with a large primary mirror, avoids large chromatic aberrations. Because the size limit of the primary mirror and vignetting due to the secondary mirror affect the total collection throughput, conditions that provide the high throughput are found through an optimization. A refraction system with four lenses forming an Ernostar system is also employed. The use of high-refractive-index glass materials enhances the freedom of the lens curvatures, resulting in suppression of the spherical and coma aberration. Moreover, sufficient throughput can be achieved, even with smaller lenses than that of a previous design given in [H. Tojo, T. Hatae, T. Sakuma, T. Hamano, K. Itami, Y. Aida, S. Suitoh, and D. Fujie, Rev. Sci. Instrum. 81, 10D539 (2010)]. The optical resolutions of the reflection and refraction systems are both sufficient for understanding the spatial structures in plasma. In particular, the spot sizes at the image of the optics are evaluated as ∼0.3 mm and ∼0.4 mm, respectively. The throughput for the two systems, including the pupil size and transmissivity, are also compared. The results show that good measurement accuracy (<10%) even at high electron temperatures (<30 keV) can be expected in the refraction system.

  9. Characterization of x-ray imaging crystal spectrometer for high-resolution spatially-resolved x-ray Thomson scattering measurements in shock-compressed experiments

    Science.gov (United States)

    Lu, J.; Hill, K. W.; Bitter, M.; Pablant, N. A.; Delgado-Aparicio, L. F.; Efthimion, P. C.; Lee, H. J.; Zastrau, U.

    2017-01-01

    We have proposed, designed and built a dual-channel x-ray imaging crystal spectrometer (XICS) for spectrally- and spatially-resolved x-ray Thomson scattering (XRTS) measurements in the Matter in Extreme Conditions (MEC) end station at the Linac Coherent Light Source (LCLS). This spectrometer employs two spherically-bent germanium (Ge) 220 crystals, which are combined to form a large aperture dispersive element with a spectral bandwidth of 300 eV that enables both the elastic and inelastic x-ray scattering peaks to be simultaneously measured. The apparatus and its characterization are described. A resolving power of 1900 was demonstrated and a spatial resolution of 12 μm was achieved in calibration tests. For XRTS measurements, a narrow-bandwidth (ΔE/Ecarbon plasma produced in shock-compressed samples of different forms of carbon. Preliminary results of the scattering experiments from Pyrolytic Graphite samples that illustrate the utility of the instrument are presented.

  10. Thomson Experiment

    CERN Multimedia

    This experiment, conducted by JJ Thomson in 1897, established the existence of the electron. Thomson won the Nobel physics prize for this work in 1906. A beam of electrons crosses the chamber emitting blue light. Adding an electric field (E) or a magnetic field (B) exerts a force on the moving electrons.Use switch E to turn on the electric field in the chamber. Then, by turning knob B, you can increase the current in the coils, generating a magnetic field. By balancing the electric and magnetic fields, Thomson was able to keep the electron beam level and deduce the ratio of the electron's charge to its mass.

  11. Heldi Thomson

    Index Scriptorium Estoniae

    1997-01-01

    Teaduspreemia autorite kollektiivile arstiteaduse alal töö "Vähktõbi Eestis 1968-1992: haigestumus, levimus, elulemus ja suremus" eest - Mati Rahu (kollektiivi juht), Tiiu Aarelaid, Kaja Gornoi, Heldi Thomson

  12. Effect of shape of scatterers and plasma frequency on the complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals

    Science.gov (United States)

    Fathollahi Khalkhali, T.; Bananej, A.

    2016-12-01

    In this study, we analyze complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals with triangular and square lattices, composed of plasma rods with different geometrical shapes in the anisotropic tellurium background. Using the finite-difference time-domain method we discuss the maximization of the complete photonic band gap width as a function of plasma frequency and plasma rods parameters with different shapes and orientations. The numerical results demonstrate that our proposed structures represent significantly wide complete photonic band gaps in comparison to previously studied dielectric-plasma photonic crystals.

  13. Experimental determination of EEDF and He{sub 2}{sup *} Rydberg-state density by Thomson scattering in a ns-pulsed atmospheric micro-discharge

    Energy Technology Data Exchange (ETDEWEB)

    Schregel, Christian-Georg; Luggenhoelscher, Dirk; Czarnetzki, Uwe [Institute for Plasma and Atomic Physics, Ruhr-University Bochum (Germany)

    2016-07-01

    An open question of major importance for the investigation of atmospheric micro plasmas is the shape of the EEDF. This has been addressed by using incoherent Thomson scattering as a non-invasive diagnostic. The technique has been applied to measure the temporal evolution (Δt=20 ns) of the EVDF for a pure Helium plasma between two plane molybdenum electrodes, 0.95 mm apart. The plasma is pulsed with a repetition rate of 5 kHz at 0.7 bar. Measurements were done by a 532 nm Nd:YAG laser and a triple grating spectrometer with a gated ICCD for detection. The setup allows for detection of electron energies between 0.5 eV and 12 eV with up to three orders of magnitude in the dynamic range. Additionally, time resolved optical emission spectra where recorded and the Helium metastable was density probed by laser absorption. With the different diagnostic data combined, variation of laser energy used in Thomson scattering could additionally be utilized as a probe for the absolute Helium Excimer Rydberg-state density, allowing a unique determination of absolute density values in the early stages of the afterglow. Peak electron densities of 2 . 10{sup 20} m{sup -3} with a peak electron temperature of 2 eV have been observed.

  14. Diagnosing collisions of magnetized, high energy density plasma flows using a combination of collective Thomson scattering, Faraday rotation, and interferometry (invited).

    Science.gov (United States)

    Swadling, G F; Lebedev, S V; Hall, G N; Patankar, S; Stewart, N H; Smith, R A; Harvey-Thompson, A J; Burdiak, G C; de Grouchy, P; Skidmore, J; Suttle, L; Suzuki-Vidal, F; Bland, S N; Kwek, K H; Pickworth, L; Bennett, M; Hare, J D; Rozmus, W; Yuan, J

    2014-11-01

    A suite of laser based diagnostics is used to study interactions of magnetised, supersonic, radiatively cooled plasma flows produced using the Magpie pulse power generator (1.4 MA, 240 ns rise time). Collective optical Thomson scattering measures the time-resolved local flow velocity and temperature across 7-14 spatial positions. The scattering spectrum is recorded from multiple directions, allowing more accurate reconstruction of the flow velocity vectors. The areal electron density is measured using 2D interferometry; optimisation and analysis are discussed. The Faraday rotation diagnostic, operating at 1053 nm, measures the magnetic field distribution in the plasma. Measurements obtained simultaneously by these diagnostics are used to constrain analysis, increasing the accuracy of interpretation.

  15. Diagnosing collisions of magnetized, high energy density plasma flows using a combination of collective Thomson scattering, Faraday rotation, and interferometry (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Swadling, G. F., E-mail: swadling@imperial.ac.uk; Lebedev, S. V.; Hall, G. N.; Patankar, S.; Stewart, N. H.; Smith, R. A.; Burdiak, G. C.; Grouchy, P. de; Skidmore, J.; Suttle, L.; Suzuki-Vidal, F.; Bland, S. N.; Kwek, K. H.; Pickworth, L.; Bennett, M.; Hare, J. D. [Plasma Physics Group, Imperial College, London SW6 7LZ (United Kingdom); Harvey-Thompson, A. J. [Sandia National Laboratory, Albuquerque, New Mexico 87185-1193 (United States); Rozmus, W. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1 (Canada); Yuan, J. [Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAE, Mianyang 621900 (China)

    2014-11-15

    A suite of laser based diagnostics is used to study interactions of magnetised, supersonic, radiatively cooled plasma flows produced using the Magpie pulse power generator (1.4 MA, 240 ns rise time). Collective optical Thomson scattering measures the time-resolved local flow velocity and temperature across 7–14 spatial positions. The scattering spectrum is recorded from multiple directions, allowing more accurate reconstruction of the flow velocity vectors. The areal electron density is measured using 2D interferometry; optimisation and analysis are discussed. The Faraday rotation diagnostic, operating at 1053 nm, measures the magnetic field distribution in the plasma. Measurements obtained simultaneously by these diagnostics are used to constrain analysis, increasing the accuracy of interpretation.

  16. Two-dimensional calculus

    CERN Document Server

    Osserman, Robert

    2011-01-01

    The basic component of several-variable calculus, two-dimensional calculus is vital to mastery of the broader field. This extensive treatment of the subject offers the advantage of a thorough integration of linear algebra and materials, which aids readers in the development of geometric intuition. An introductory chapter presents background information on vectors in the plane, plane curves, and functions of two variables. Subsequent chapters address differentiation, transformations, and integration. Each chapter concludes with problem sets, and answers to selected exercises appear at the end o

  17. Two dimensional vernier

    Science.gov (United States)

    Juday, Richard D. (Inventor)

    1992-01-01

    A two-dimensional vernier scale is disclosed utilizing a cartesian grid on one plate member with a polar grid on an overlying transparent plate member. The polar grid has multiple concentric circles at a fractional spacing of the spacing of the cartesian grid lines. By locating the center of the polar grid on a location on the cartesian grid, interpolation can be made of both the X and Y fractional relationship to the cartesian grid by noting which circles coincide with a cartesian grid line for the X and Y direction.

  18. Diffuse X-ray scattering near a two-dimensional solid-liquid phase transition at the n-hexane-water interface

    Science.gov (United States)

    Tikhonov, A. M.

    2016-09-01

    According to experimental data on X-ray scattering and reflectometry with synchrotron radiation, a twodimensional crystallization phase transition in a monolayer of melissic acid at the n-hexane-water interface with a decrease in the temperature occurs after a wetting transition.

  19. Diffuse X-ray scattering near a two-dimensional solid–liquid phase transition at the n-hexane–water interface

    Energy Technology Data Exchange (ETDEWEB)

    Tikhonov, A. M. [Russian Academy of Sciences (RAS), Moscow (Russian Federation). Kapitza Inst. for Physical Problems

    2016-09-01

    According to experimental data on X-ray scattering and reflectometry with synchrotron radiation, a twodimensional crystallization phase transition in a monolayer of melissic acid at the n-hexane–water interface with a decrease in the temperature occurs after a wetting transition.

  20. Effect of shape of scatterers and plasma frequency on the complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Fathollahi Khalkhali, T., E-mail: tfathollahi@aeoi.org.ir; Bananej, A.

    2016-12-16

    In this study, we analyze complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals with triangular and square lattices, composed of plasma rods with different geometrical shapes in the anisotropic tellurium background. Using the finite-difference time-domain method we discuss the maximization of the complete photonic band gap width as a function of plasma frequency and plasma rods parameters with different shapes and orientations. The numerical results demonstrate that our proposed structures represent significantly wide complete photonic band gaps in comparison to previously studied dielectric-plasma photonic crystals. - Highlights: • In this paper, we have investigated plasma photonic crystals. • Plasma is a kind of dispersive medium with its equivalent refractive index related to the frequency of an incident EM wave. • In this work, our simulations are performed using the Meep implementation of the finite-difference time-domain (FDTD) method. • For this study, the lattice structures investigated are triangular and square. • Extensive calculations reveal that almost all of these structures represent wide complete band gaps.

  1. The Two-dimensional Electromagnetic Scattering from Periodic Chiral Structures and Its Finite Element Approximation%周期手性介质中二维电磁散射问题及有限元逼近

    Institute of Scientific and Technical Information of China (English)

    张德悦; 马富明

    2004-01-01

    In this paper, we consider the electromagnetic scattering from periodic chiral structures. The structure is periodic in one direction and invariant in another direction. The electromagnetic fields in the chiral medium are governed by the Maxwell equations together with the Drude-Born-Fedorov equations. We simplify the problem to a two-dimensional scattering problem and we show that for all but possibly a discrete set of wave numbers, there is a unique quasi-periodic weak solution to the diffraction problem. The diffraction problem can be solved by finite element method. We also establish uniform error estimates for the finite element method and the error estimates when the truncation of the nonlocal transparent boundary operators takes place.

  2. Initial result of collective Thomson scattering using 77 GHz gyrotron for bulk and tail ion diagnostics in the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Nishiura, M; Kubo, S; Tanaka, K; Shimozuma, T; Mutoh, T; Kawahata, K; Watari, T [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Tamura, N [Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 (Japan); Saito, T; Tatematsu, Y [FIR FU, University of Fukui, 3-9-1 Bunkyo, Fukui, 910-8507 (Japan); Notake, T, E-mail: nishiura@nifs.ac.j [RIKEN, 519-1399 Aoba, Aramaki, Aoba-ku, Sendai, 980-0845 (Japan)

    2010-05-01

    The collective Thomson scattering (CTS) technique has been utilized with the backscattering configuration in the collective scattering regime to diagnose the velocity distribution functions in the Large Helical Device (LHD). The receiver was equipped with 16 channels and the first test has been carried out using the eight channels for scattered radiation and these channels cover a few GHz frequency shift from the 76.95 GHz probe beam. During the discharge, the electron density and temperature at the central region of the LHD are 1x10{sup 19}m{sup -3}, and 1.0 keV, respectively. The probing beam with rectangular wave modulation is injected by 50 Hz in order to be distinct from the background electron cyclotron emission (ECE). The scattered radiation is resolved successfully at each channel of CTS receiver system. The detected signals of bulk ion and electron components are by a factor of 10 {approx} 10{sup 2} larger than the background ECE signal. We found that the measured spectra are in reasonably agreement with the theoretical spectra calculated by using the reliable measured electron temperature and density for input parameters. The CTS receiver system will be improved to obtain more accurate velocity distributions in high temperature plasmas.

  3. THE THOMSON SURFACE. I. REALITY AND MYTH

    Energy Technology Data Exchange (ETDEWEB)

    Howard, T. A.; DeForest, C. E., E-mail: howard@boulder.swri.edu [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2012-06-20

    The solar corona and heliosphere are visible via sunlight that is Thomson-scattered off free electrons and detected by coronagraphs and heliospheric imagers. It is well known that these instruments are most responsive to material at the 'Thomson surface', the sphere with a diameter passing through both the observer and the Sun. It is less well known that in fact the Thomson scattering efficiency is minimized on the Thomson surface. Unpolarized heliospheric imagers such as STEREO/HI are thus approximately equally responsive to material over more than a 90 Degree-Sign range of solar exit angles at each given position in the image plane. We call this range of angles the 'Thomson plateau'. We observe that heliospheric imagers are actually more sensitive to material far from the Thomson surface than close to it, at a fixed radius from the Sun. We review the theory of Thomson scattering as applied to heliospheric imaging, feature detection in the presence of background noise, geometry inference, and feature mass measurement. We show that feature detection is primarily limited by observing geometry and field of view, that the highest sensitivity for detection of density features is to objects close to the observer, that electron surface density inference is independent of geometry across the Thomson plateau, and that mass inference varies with observer distance in all geometries. We demonstrate the sensitivity results with a few examples of features detected by STEREO, far from the Thomson surface.

  4. The Thomson Surface. I. Reality and Myth

    Science.gov (United States)

    Howard, T. A.; DeForest, C. E.

    2012-06-01

    The solar corona and heliosphere are visible via sunlight that is Thomson-scattered off free electrons and detected by coronagraphs and heliospheric imagers. It is well known that these instruments are most responsive to material at the "Thomson surface," the sphere with a diameter passing through both the observer and the Sun. It is less well known that in fact the Thomson scattering efficiency is minimized on the Thomson surface. Unpolarized heliospheric imagers such as STEREO/HI are thus approximately equally responsive to material over more than a 90° range of solar exit angles at each given position in the image plane. We call this range of angles the "Thomson plateau." We observe that heliospheric imagers are actually more sensitive to material far from the Thomson surface than close to it, at a fixed radius from the Sun. We review the theory of Thomson scattering as applied to heliospheric imaging, feature detection in the presence of background noise, geometry inference, and feature mass measurement. We show that feature detection is primarily limited by observing geometry and field of view, that the highest sensitivity for detection of density features is to objects close to the observer, that electron surface density inference is independent of geometry across the Thomson plateau, and that mass inference varies with observer distance in all geometries. We demonstrate the sensitivity results with a few examples of features detected by STEREO, far from the Thomson surface.

  5. Measurements of the fast-ion distribution function at ASDEX upgrade by collective Thomson scattering (CTS) using active and passive views

    Science.gov (United States)

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

    2015-03-01

    Collective Thomson scattering (CTS) can provide measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. On ASDEX Upgrade, the measured spectra include an additional signal which previously has hampered data interpretation. A new set-up using two independent heterodyne receiver systems enables subtraction of the additional part from the total spectrum, revealing the resulting CTS spectrum. Here we present CTS measurements from the plasma centre obtained in L-mode and H-mode plasmas with and without neutral beam injection (NBI). For the first time, the measured spectra agree quantitatively with the synthetic spectra in periods with and without NBI heating. For the discharges investigated, the central velocity distribution of neutral beam ions can be described by classical slowing down. These results will have a major impact on ITER physics exploration, since CTS is presently the only diagnostic to measure the confined alpha particles produced by the fusion reactions.

  6. Two-dimensional optical spectroscopy

    CERN Document Server

    Cho, Minhaeng

    2009-01-01

    Discusses the principles and applications of two-dimensional vibrational and optical spectroscopy techniques. This book provides an account of basic theory required for an understanding of two-dimensional vibrational and electronic spectroscopy.

  7. Measurement of high-dynamic range x-ray Thomson scattering spectra for the characterization of nano-plasmas at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, M. J., E-mail: macdonm@umich.edu [University of Michigan, Ann Arbor, Michigan 48109 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Gorkhover, T. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Technische Universität, 10623 Berlin (Germany); Bachmann, B.; Hau-Riege, S. P.; Pardini, T.; Döppner, T. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Bucher, M. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Argonne National Lab, Lemont, Illinois 60439 (United States); Carron, S. [California Lutheran University, Thousand Oaks, California 91360 (United States); Coffee, R. N.; Fletcher, L. B.; Gamboa, E. J.; Glenzer, S. H.; Göde, S.; Krzywinski, J.; O’Grady, C. P.; Osipov, T.; Swiggers, M. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Drake, R. P. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Ferguson, K. R. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford University, Stanford, California 94305 (United States); Kraus, D. [University of California, Berkeley, California 94720 (United States); and others

    2016-11-15

    Atomic clusters can serve as ideal model systems for exploring ultrafast (∼100 fs) laser-driven ionization dynamics of dense matter on the nanometer scale. Resonant absorption of optical laser pulses enables heating to temperatures on the order of 1 keV at near solid density conditions. To date, direct probing of transient states of such nano-plasmas was limited to coherent x-ray imaging. Here we present the first measurement of spectrally resolved incoherent x-ray scattering from clusters, enabling measurements of transient temperature, densities, and ionization. Single shot x-ray Thomson scattering signals were recorded at 120 Hz using a crystal spectrometer in combination with a single-photon counting and energy-dispersive pnCCD. A precise pump laser collimation scheme enabled recording near background-free scattering spectra from Ar clusters with an unprecedented dynamic range of more than 3 orders of magnitude. Such measurements are important for understanding collective effects in laser-matter interactions on femtosecond time scales, opening new routes for the development of schemes for their ultrafast control.

  8. Measurement of high-dynamic range x-ray Thomson scattering spectra for the characterization of nano-plasmas at LCLS

    Science.gov (United States)

    MacDonald, M. J.; Gorkhover, T.; Bachmann, B.; Bucher, M.; Carron, S.; Coffee, R. N.; Drake, R. P.; Ferguson, K. R.; Fletcher, L. B.; Gamboa, E. J.; Glenzer, S. H.; Göde, S.; Hau-Riege, S. P.; Kraus, D.; Krzywinski, J.; Levitan, A. L.; Meiwes-Broer, K.-H.; O'Grady, C. P.; Osipov, T.; Pardini, T.; Peltz, C.; Skruszewicz, S.; Swiggers, M.; Bostedt, C.; Fennel, T.; Döppner, T.

    2016-11-01

    Atomic clusters can serve as ideal model systems for exploring ultrafast (˜100 fs) laser-driven ionization dynamics of dense matter on the nanometer scale. Resonant absorption of optical laser pulses enables heating to temperatures on the order of 1 keV at near solid density conditions. To date, direct probing of transient states of such nano-plasmas was limited to coherent x-ray imaging. Here we present the first measurement of spectrally resolved incoherent x-ray scattering from clusters, enabling measurements of transient temperature, densities, and ionization. Single shot x-ray Thomson scattering signals were recorded at 120 Hz using a crystal spectrometer in combination with a single-photon counting and energy-dispersive pnCCD. A precise pump laser collimation scheme enabled recording near background-free scattering spectra from Ar clusters with an unprecedented dynamic range of more than 3 orders of magnitude. Such measurements are important for understanding collective effects in laser-matter interactions on femtosecond time scales, opening new routes for the development of schemes for their ultrafast control.

  9. Mobility anisotropy of two-dimensional semiconductors

    Science.gov (United States)

    Lang, Haifeng; Zhang, Shuqing; Liu, Zhirong

    2016-12-01

    The carrier mobility of anisotropic two-dimensional semiconductors under longitudinal acoustic phonon scattering was theoretically studied using deformation potential theory. Based on the Boltzmann equation with the relaxation time approximation, an analytic formula of intrinsic anisotropic mobility was derived, showing that the influence of effective mass on mobility anisotropy is larger than those of deformation potential constant or elastic modulus. Parameters were collected for various anisotropic two-dimensional materials (black phosphorus, Hittorf's phosphorus, BC2N , MXene, TiS3, and GeCH3) to calculate their mobility anisotropy. It was revealed that the anisotropic ratio is overestimated by the previously described method.

  10. Scattering behaviour of a two-dimensional electron gas induced by Al composition fluctuation in AlxGa1-xN barriers in AlxGa1-xN/GaN heterostructures

    Institute of Scientific and Technical Information of China (English)

    Wang Yan; Shen Bo; Xu Fu-Jun; Huang Sen; Miao Zhen-Lin; Lin Fang; Yang Zhi-Jian; Zhang Guo-Yi

    2009-01-01

    This paper reports that cathodoluminescence (CL) measurements have been done to study the alloy fluctuation of the Al0.3Ca0.7N layer in Al0.3Ca0.7N/GaN heterostructures. The CL images and linescanning results demonstrate the existcnce of compositional fluctuation of Al in the Al0.3Ga0.7N barrier. A model using a δ-shape perturbation Hamilton function has been proposed to simulate the scattering probability of the two dimensional electron gases (2DEG) induced by Al composition fluctuation. Two factors, including conduction band fluctuation and polarization electric field variation, induced by the Al composition fluctuation have been taken into account. The scattering relaxation time induced by both factors has been estimated to be 0.31 ns and 0.0078 us, respectively, indicating that the variation of the piezoelectric field is dominant in the scattering of the 2DEG induced by Al fluctuation.

  11. A high-energy, high-flux source of gamma-rays from all-optical non-linear Thomson scattering

    Science.gov (United States)

    Corvan, D. J.; Zepf, M.; Sarri, G.

    2016-09-01

    γ-Ray sources are among the most fundamental experimental tools currently available to modern physics. As well as the obvious benefits to fundamental research, an ultra-bright source of γ-rays could form the foundation of scanning of shipping containers for special nuclear materials and provide the bases for new types of cancer therapy. However, for these applications to prove viable, γ-ray sources must become compact and relatively cheap to manufacture. In recent years, advances in laser technology have formed the cornerstone of optical sources of high energy electrons which already have been used to generate synchrotron radiation on a compact scale. Exploiting the scattering induced by a second laser, one can further enhance the energy and number of photons produced provided the problems of synchronisation and compact γ-ray detection are solved. Here, we report on the work that has been done in developing an all-optical and hence, compact non-linear Thomson scattering source, including the new methods of synchronisation and compact γ-ray detection. We present evidence of the generation of multi-MeV (maximum 16-18 MeV) and ultra-high brilliance (exceeding 1020 photons s-1mm-2mrad-2 0.1% BW at 15 MeV) γ-ray beams. These characteristics are appealing for the paramount practical applications mentioned above.

  12. Measurements of Ionic Structure in Shock Compressed Lithium Hydride from Ultra-fast X-ray Thomson Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kritcher, A L; Neumayer, P; Brown, C; Davis, P; Doppner, T; Falcone, R W; Gericke, D O; Gregori, G; Holst, B; Landen, O L; Lee, H J; Morse, E C; Pelka, A; Redmer, R; Roth, M; Vorberger, J; Wunsch, K; Glenzer, S H

    2009-07-14

    We present the first ultrafast temporally, spectrally and angularly resolved x-ray scattering measurements from shock-compressed matter. These laser-compressed lithium-hydride samples are well characterized by inelastic Compton and Plasmon scattering of a K-{alpha} x-ray probe providing independent measurements of temperature and density. The experimental spectra yield the absolute elastic and inelastic scattering intensities from the measured density of free electrons. The data show excellent agreement with the total intensity and structure when using the two-species form factor and accounting for ionic screening.

  13. Nonlinear effects in Thomson backscattering

    Science.gov (United States)

    Maroli, C.; Petrillo, V.; Tomassini, P.; Serafini, L.

    2013-03-01

    We analyze the nonlinear classical effects of the X/γ radiation produced by Thomson/Compton sources. We confirm the development of spectral fringes of the radiation on axis, which comports broadening, shift, and deformation of the spectrum. For the nominal parameters of the SPARC-LAB Thomson scattering and of the European Proposal for the gamma source ELI-NP, however, the radiation, when collected in the suitable acceptance angle, does not reveal many differences from that predicted by the linear model and the nonlinear redshift is subdominant with respect to the quantum recoil. An experiment aimed to the study of the nonlinearities is proposed on the SPARC-LAB source.

  14. High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source.

    Science.gov (United States)

    Fletcher, L B; Zastrau, U; Galtier, E; Gamboa, E J; Goede, S; Schumaker, W; Ravasio, A; Gauthier, M; MacDonald, M J; Chen, Z; Granados, E; Lee, H J; Fry, A; Kim, J B; Roedel, C; Mishra, R; Pelka, A; Kraus, D; Barbrel, B; Döppner, T; Glenzer, S H

    2016-11-01

    We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].

  15. High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

    Science.gov (United States)

    Fletcher, L. B.; Zastrau, U.; Galtier, E.; Gamboa, E. J.; Goede, S.; Schumaker, W.; Ravasio, A.; Gauthier, M.; MacDonald, M. J.; Chen, Z.; Granados, E.; Lee, H. J.; Fry, A.; Kim, J. B.; Roedel, C.; Mishra, R.; Pelka, A.; Kraus, D.; Barbrel, B.; Döppner, T.; Glenzer, S. H.

    2016-11-01

    We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].

  16. High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, L. B., E-mail: lbfletch@slac.stanford.edu; Galtier, E.; Gamboa, E. J.; Schumaker, W.; Gauthier, M.; Granados, E.; Lee, H. J.; Fry, A.; Kim, J. B.; Roedel, C.; Mishra, R.; Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Zastrau, U. [European XFEL, Schenefeld (Germany); Goede, S. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); European XFEL, Schenefeld (Germany); Ravasio, A. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Laboratoire pour l’Utilisation des Lasers Intenses, Palaiseau Cedex (France); MacDonald, M. J. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); University of Michigan, Ann Arbor, Michigan 48109 (United States); Chen, Z. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); University of Alberta, Edmonton, Alberta T6G 2R3 (Canada); Pelka, A. [Helmholtz Zentrum Dresden-Rossendorf, Dresden (Germany); Kraus, D. [Helmholtz Zentrum Dresden-Rossendorf, Dresden (Germany); Department of Physics, University of California Berkeley, Berkeley, California 94720 (United States); Barbrel, B. [Department of Physics, University of California Berkeley, Berkeley, California 94720 (United States); and others

    2016-11-15

    We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].

  17. Statistical modeling of deconvolution procedures for improving the resolution of measuring electron temperature profiles in tokamak plasmas by Thomson scattering lidar

    Science.gov (United States)

    Dreischuh, Tanja N.; Gurdev, Ljuan L.; Stoyanov, Dimitar V.

    2010-10-01

    The potentialities are investigated, by statistical modeling, of deconvolution techniques for high-resolution restoration of electron temperature profiles in fusion plasma reactors like Joint European Torus (JET) measured by Thomson scattering lidar using the center-of-mass wavelength approach. The sensing laser pulse shape and the receiving-system response function are assumed to be exponentially-shaped. The plasma light background influence is taken into account as well as the Poisson fluctuations of the photoelectron number after the photocathode enhanced in the process of cascade multiplying in the employed microchannel photomultiplier tube. It is shown that the Fourier-deconvolution of the measured long-pulse (lidar-response-convolved) lidar profiles, at relatively high and low signal-to-noise ratios, ensures a higher accuracy of recovering the electron temperature profiles with three times higher range resolution compared to the case without deconvolution. The final resolution scale is determined by the width of the window of an optimum monotone sharp-cutoff digital noise-suppressing (noise-controlling) filter applied to the measured lidar profiles.

  18. Application of Thomson scattering at 1.06{mu}m as a diagnostic for spatial profile measurements of electron temperature and density on the TCV tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Franke, S. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

    1997-04-01

    The variable configuration tokamak, TCV, in operation at CRPP since the end of 1991, is a particularly challenging machine with regard to the experimental system that must provide essential information regarding properties of confined plasmas with strongly shaped, non-circular cross-sections. The importance of the energy confinement issue in a machine designed specifically for the investigation of the effect of plasma shape on confinement and stability is self-evident, as is the necessity for a diagnostic capable of providing the profiles of electron temperature and density required for evaluation of this confinement. For TCV, a comprehensive Thomson Scattering (TS) diagnostic was the natural choice, specifically owing to the resulting spatially localized and time resolved measurement. The details of the system installed on TCV, together with the results obtained from the diagnostic comprise the subject matter of this thesis. A first version of the diagnostic was equipped with only ten observation volumes. In this case, adequate spatial resolution can only be maintained if measurements are limited to plasmas located in the upper half of the highly elongated TCV vacuum vessel. The system has recently been upgraded through the addition of a further fifteen observation volumes, together with major technical improvements in the scattered light detection system. This new version now permits TS observations in all TCV plasma configurations, including equilibria produced in the lower and upper halves of the vacuum vessel and the highly elongated plasmas now routinely created. Whilst a description of the new detection system along with some results obtained using the extended set of observation volumes are included, this thesis reports principally on the hardware details of and the interpretation of data from the original, ten observation volume system. (author) figs., tabs., 75 refs.

  19. A high-energy, high-flux source of gamma-rays from all-optical non-linear Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Corvan, D.J., E-mail: dcorvan01@qub.ac.uk; Zepf, M.; Sarri, G.

    2016-09-01

    γ-Ray sources are among the most fundamental experimental tools currently available to modern physics. As well as the obvious benefits to fundamental research, an ultra-bright source of γ-rays could form the foundation of scanning of shipping containers for special nuclear materials and provide the bases for new types of cancer therapy. However, for these applications to prove viable, γ-ray sources must become compact and relatively cheap to manufacture. In recent years, advances in laser technology have formed the cornerstone of optical sources of high energy electrons which already have been used to generate synchrotron radiation on a compact scale. Exploiting the scattering induced by a second laser, one can further enhance the energy and number of photons produced provided the problems of synchronisation and compact γ-ray detection are solved. Here, we report on the work that has been done in developing an all-optical and hence, compact non-linear Thomson scattering source, including the new methods of synchronisation and compact γ-ray detection. We present evidence of the generation of multi-MeV (maximum 16–18 MeV) and ultra-high brilliance (exceeding 10{sup 20} photons s{sup −1}mm{sup −2}mrad{sup −2} 0.1% BW at 15 MeV) γ-ray beams. These characteristics are appealing for the paramount practical applications mentioned above. - Highlights: • How synchrotron radiation can be produced in an all optical setting using laser-plasmas. • Generating high-energy, high-flux gamma ray beams. • Presenting results from a recent NLTS experimental campaign. • Reveal insight into the experimental techniques employed.

  20. Application of Thomson scattering at 1.06{mu}m as a diagnostic for spatial profile measurements of electron temperature and density on the TCV tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Franke, S. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

    1997-04-01

    The variable configuration tokamak, TCV, in operation at CRPP since the end of 1991, is a particularly challenging machine with regard to the experimental system that must provide essential information regarding properties of confined plasmas with strongly shaped, non-circular cross-sections. The importance of the energy confinement issue in a machine designed specifically for the investigation of the effect of plasma shape on confinement and stability is self-evident, as is the necessity for a diagnostic capable of providing the profiles of electron temperature and density required for evaluation of this confinement. For TCV, a comprehensive Thomson Scattering (TS) diagnostic was the natural choice, specifically owing to the resulting spatially localized and time resolved measurement. The details of the system installed on TCV, together with the results obtained from the diagnostic comprise the subject matter of this thesis. A first version of the diagnostic was equipped with only ten observation volumes. In this case, adequate spatial resolution can only be maintained if measurements are limited to plasmas located in the upper half of the highly elongated TCV vacuum vessel. The system has recently been upgraded through the addition of a further fifteen observation volumes, together with major technical improvements in the scattered light detection system. This new version now permits TS observations in all TCV plasma configurations, including equilibria produced in the lower and upper halves of the vacuum vessel and the highly elongated plasmas now routinely created. Whilst a description of the new detection system along with some results obtained using the extended set of observation volumes are included, this thesis reports principally on the hardware details of and the interpretation of data from the original, ten observation volume system. (author) figs., tabs., 75 refs.

  1. 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...

  2. Phase space distribution of an electron beam emerging from Compton/Thomson back-scattering by an intense laser pulse

    Science.gov (United States)

    Petrillo, V.; Chaikovska, I.; Ronsivalle, C.; Rossi, A. R.; Serafini, L.; Vaccarezza, C.

    2013-01-01

    We analyze the energy distribution of a relativistic electron beam after the Compton back-scattering by a counterpropagating laser field. The analysis is performed for parameters in the range of realistic X-γ sources, in the framework of the Quantum Electrodynamics, by means of the code CAIN. The results lead to the conclusion that, in the regime considered, the main effect is the initial formation of stripes, followed by the diffusion of the most energetic particles toward lower values in the longitudinal phase space, with a final increase of the electron energy bandwidth.

  3. Edge profile analysis of Joint European Torus (JET) Thomson scattering data: Quantifying the systematic error due to edge localised mode synchronisation.

    Science.gov (United States)

    Leyland, M J; Beurskens, M N A; Flanagan, J C; Frassinetti, L; Gibson, K J; Kempenaars, M; Maslov, M; Scannell, R

    2016-01-01

    The Joint European Torus (JET) high resolution Thomson scattering (HRTS) system measures radial electron temperature and density profiles. One of the key capabilities of this diagnostic is measuring the steep pressure gradient, termed the pedestal, at the edge of JET plasmas. The pedestal is susceptible to limiting instabilities, such as Edge Localised Modes (ELMs), characterised by a periodic collapse of the steep gradient region. A common method to extract the pedestal width, gradient, and height, used on numerous machines, is by performing a modified hyperbolic tangent (mtanh) fit to overlaid profiles selected from the same region of the ELM cycle. This process of overlaying profiles, termed ELM synchronisation, maximises the number of data points defining the pedestal region for a given phase of the ELM cycle. When fitting to HRTS profiles, it is necessary to incorporate the diagnostic radial instrument function, particularly important when considering the pedestal width. A deconvolved fit is determined by a forward convolution method requiring knowledge of only the instrument function and profiles. The systematic error due to the deconvolution technique incorporated into the JET pedestal fitting tool has been documented by Frassinetti et al. [Rev. Sci. Instrum. 83, 013506 (2012)]. This paper seeks to understand and quantify the systematic error introduced to the pedestal width due to ELM synchronisation. Synthetic profiles, generated with error bars and point-to-point variation characteristic of real HRTS profiles, are used to evaluate the deviation from the underlying pedestal width. We find on JET that the ELM synchronisation systematic error is negligible in comparison to the statistical error when assuming ten overlaid profiles (typical for a pre-ELM fit to HRTS profiles). This confirms that fitting a mtanh to ELM synchronised profiles is a robust and practical technique for extracting the pedestal structure.

  4. 基于激光二维散射原理在线测量表面粗糙度%On-line Measurement of Surface Roughness Based on Laser Two-dimensional Scattering Principle

    Institute of Scientific and Technical Information of China (English)

    张秋佳; 赵玉华; 韩冬; 余平; 刘明珠

    2011-01-01

    Referring to the complicated operating and bad field measuring of existing surface roughness, an on-line measurement method is presented based on laser two-dimensional scattering principle. The method proposed can not only measure the surface roughness parameters, but also figure out the surface topography. In this measurement, by using non-diffraction laser beam as light source and high accuracy CCD camera as displacement sensor, and applying the method of signal processing of surface roughness by Matlab, real-time measurement of surface roughness can be realized.This method is realized with modularized design, and has the advantages of simple structure, powerful real-time processing capability, high-precision measurement, visual display, and easy operation, etc.%针对现有零件表面粗糙度测量仪器操作复杂,现场测量能力差的问题,提出一种基于激光二维散射的在线测量方法,该方法不仅可以测量表面粗糙度的统计参数,而且可以反映出表面纹理的形貌特征.在测量中,用无衍射激光光束作光源,用高精度的CCD摄像机作位移传感器,利用Matlab进行表面粗糙度测量数据采集与处理,使表面粗糙度在线检测成为可能.该方法运用模块化设计,具有结构简单、实时处理能力强、测试精度高、显示结果直观、不会划伤被测件等优点.

  5. 周期子波在二维声辐射和声散射中的应用%On Reducing High Computational Cost with Periodic Wavelets in Solving Two-Dimensional Acoustic Radiation and Scattering

    Institute of Scientific and Technical Information of China (English)

    文立华; 张京妹; 孙进才

    2001-01-01

    Traditional methods for solving acoustic problems in engineering often require the solution of non-symmetric full matrix, whose dimension may be even higher than 10 000 and thus computational cost becomes quite high. To overcome this serious shortcoming, we propose a new periodic wavelet approach for the Helmholtz integral-equation solution of two-dimensional acoustic radiation and scattering over curved computation domain. We expand the boundary quantities in terms of periodic and orthogonal wavelets and we obtain the algebraic equations needed for solving the acoustic problems with Dirichlet, Neumann and mixed conditions. We evaluate the coefficients with fast wavelet transform. The advantage of the new approach is a highly sparse matrix system. We compare the numerical results obtained with our new approach, boundary element method or analytical solutions; the numerical results, as given in Table 1, show that our new approach converges rapidly and is of good accuracy.%提出了一种新的求解二维Helmholtz积分方程的方法。它通过将边界量用周期子波展开,将Helmholtz积分方程化为一组代数方程求解。即可求解Dirichlet、Neumann问题,也可求解混合边值问题。方程的系数形成可用快速子波变换。用该方法形成的Helmholtz积分方程的系数矩阵是一稀疏矩阵。这样大大提高了计算效率。本文算例表明:该方法收敛快,精度高,相同的精度下,本文方法求解的未知量大大少于边界元所用未知量。

  6. Mobility anisotropy of two-dimensional semiconductors

    CERN Document Server

    Lang, Haifeng; Liu, Zhirong

    2016-01-01

    The carrier mobility of anisotropic two-dimensional (2D) semiconductors under longitudinal acoustic (LA) phonon scattering was theoretically studied with the deformation potential theory. Based on Boltzmann equation with relaxation time approximation, an analytic formula of intrinsic anisotropic mobility was deduced, which shows that the influence of effective mass to the mobility anisotropy is larger than that of deformation potential constant and elastic modulus. Parameters were collected for various anisotropic 2D materials (black phosphorus, Hittorf's phosphorus, BC$_2$N, MXene, TiS$_3$, GeCH$_3$) to calculate their mobility anisotropy. It was revealed that the anisotropic ratio was overestimated in the past.

  7. Design of practical alignment device in KSTAR Thomson diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. H., E-mail: jhlee@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); University of Science and Technology (UST), Daejeon (Korea, Republic of); Lee, S. H. [National Fusion Research Institute, Daejeon (Korea, Republic of); Yamada, I. [National Institute for Fusion Science, Toki (Japan)

    2016-11-15

    The precise alignment of the laser path and collection optics in Thomson scattering measurements is essential for accurately determining electron temperature and density in tokamak experiments. For the last five years, during the development stage, the KSTAR tokamak’s Thomson diagnostic system has had alignment fibers installed in its optical collection modules, but these lacked a proper alignment detection system. In order to address these difficulties, an alignment verifying detection device between lasers and an object field of collection optics is developed. The alignment detection device utilizes two types of filters: a narrow laser band wavelength for laser, and a broad wavelength filter for Thomson scattering signal. Four such alignment detection devices have been successfully developed for the KSTAR Thomson scattering system in this year, and these will be tested in KSTAR experiments in 2016. In this paper, we present the newly developed alignment detection device for KSTAR’s Thomson scattering diagnostics.

  8. Rothmund - Thomson Syndrome

    Directory of Open Access Journals (Sweden)

    Sharma N. L

    2003-01-01

    Full Text Available Rothmund-Thomson syndrome is a rare geno-photodermatosis of children. Poikilodermatous cutaneous changes, growth retardation, juvenile cataract and high incidence of malignancy are its classical features. A Thomson type of Rothmund-Thomson syndrome with characteristic poikiloderma congenitale, growth retardation, absence of juvenile cataract and parental non-consanguinity is described in an 8 year old Indian girl.

  9. Two-dimensional liquid chromatography

    DEFF Research Database (Denmark)

    Græsbøll, Rune

    of this thesis is on online comprehensive two-dimensional liquid chromatography (online LC×LC) with reverse phase in both dimensions (online RP×RP). Since online RP×RP has not been attempted before within this research group, a significant part of this thesis consists of knowledge and experience gained...

  10. Two dimensional unstable scar statistics.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Kotulski, Joseph Daniel; Lee, Kelvin S. H. (ITT Industries/AES Los Angeles, CA)

    2006-12-01

    This report examines the localization of time harmonic high frequency modal fields in two dimensional cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This paper examines the enhancements for these unstable orbits when the opposing mirrors are both convex and concave. In the latter case the construction includes the treatment of interior foci.

  11. Two-Dimensional Vernier Scale

    Science.gov (United States)

    Juday, Richard D.

    1992-01-01

    Modified vernier scale gives accurate two-dimensional coordinates from maps, drawings, or cathode-ray-tube displays. Movable circular overlay rests on fixed rectangular-grid overlay. Pitch of circles nine-tenths that of grid and, for greatest accuracy, radii of circles large compared with pitch of grid. Scale enables user to interpolate between finest divisions of regularly spaced rule simply by observing which mark on auxiliary vernier rule aligns with mark on primary rule.

  12. Two-dimensional liquid chromatography

    DEFF Research Database (Denmark)

    Græsbøll, Rune

    Two-dimensional liquid chromatography has received increasing interest due to the rise in demand for analysis of complex chemical mixtures. Separation of complex mixtures is hard to achieve as a simple consequence of the sheer number of analytes, as these samples might contain hundreds or even...... dimensions. As a consequence of the conclusions made within this thesis, the research group has, for the time being, decided against further development of online LC×LC systems, since it was not deemed ideal for the intended application, the analysis of the polar fraction of oil. Trap-and...

  13. Two-dimensional capillary origami

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, N.D., E-mail: nbrubaker@math.arizona.edu; Lega, J., E-mail: lega@math.arizona.edu

    2016-01-08

    We describe a global approach to the problem of capillary origami that captures all unfolded equilibrium configurations in the two-dimensional setting where the drop is not required to fully wet the flexible plate. We provide bifurcation diagrams showing the level of encapsulation of each equilibrium configuration as a function of the volume of liquid that it contains, as well as plots representing the energy of each equilibrium branch. These diagrams indicate at what volume level the liquid drop ceases to be attached to the endpoints of the plate, which depends on the value of the contact angle. As in the case of pinned contact points, three different parameter regimes are identified, one of which predicts instantaneous encapsulation for small initial volumes of liquid. - Highlights: • Full solution set of the two-dimensional capillary origami problem. • Fluid does not necessarily wet the entire plate. • Global energy approach provides exact differential equations satisfied by minimizers. • Bifurcation diagrams highlight three different regimes. • Conditions for spontaneous encapsulation are identified.

  14. Phonon hydrodynamics in two-dimensional materials.

    Science.gov (United States)

    Cepellotti, Andrea; Fugallo, Giorgia; Paulatto, Lorenzo; Lazzeri, Michele; Mauri, Francesco; Marzari, Nicola

    2015-03-06

    The conduction of heat in two dimensions displays a wealth of fascinating phenomena of key relevance to the scientific understanding and technological applications of graphene and related materials. Here, we use density-functional perturbation theory and an exact, variational solution of the Boltzmann transport equation to study fully from first-principles phonon transport and heat conductivity in graphene, boron nitride, molybdenum disulphide and the functionalized derivatives graphane and fluorographene. In all these materials, and at variance with typical three-dimensional solids, normal processes keep dominating over Umklapp scattering well-above cryogenic conditions, extending to room temperature and more. As a result, novel regimes emerge, with Poiseuille and Ziman hydrodynamics, hitherto typically confined to ultra-low temperatures, characterizing transport at ordinary conditions. Most remarkably, several of these two-dimensional materials admit wave-like heat diffusion, with second sound present at room temperature and above in graphene, boron nitride and graphane.

  15. Two-dimensional quantum repeaters

    Science.gov (United States)

    Wallnöfer, J.; Zwerger, M.; Muschik, C.; Sangouard, N.; Dür, W.

    2016-11-01

    The endeavor to develop quantum networks gave rise to a rapidly developing field with far-reaching applications such as secure communication and the realization of distributed computing tasks. This ultimately calls for the creation of flexible multiuser structures that allow for quantum communication between arbitrary pairs of parties in the network and facilitate also multiuser applications. To address this challenge, we propose a two-dimensional quantum repeater architecture to establish long-distance entanglement shared between multiple communication partners in the presence of channel noise and imperfect local control operations. The scheme is based on the creation of self-similar multiqubit entanglement structures at growing scale, where variants of entanglement swapping and multiparty entanglement purification are combined to create high-fidelity entangled states. We show how such networks can be implemented using trapped ions in cavities.

  16. Two-dimensional capillary origami

    Science.gov (United States)

    Brubaker, N. D.; Lega, J.

    2016-01-01

    We describe a global approach to the problem of capillary origami that captures all unfolded equilibrium configurations in the two-dimensional setting where the drop is not required to fully wet the flexible plate. We provide bifurcation diagrams showing the level of encapsulation of each equilibrium configuration as a function of the volume of liquid that it contains, as well as plots representing the energy of each equilibrium branch. These diagrams indicate at what volume level the liquid drop ceases to be attached to the endpoints of the plate, which depends on the value of the contact angle. As in the case of pinned contact points, three different parameter regimes are identified, one of which predicts instantaneous encapsulation for small initial volumes of liquid.

  17. Two-dimensional cubic convolution.

    Science.gov (United States)

    Reichenbach, Stephen E; Geng, Frank

    2003-01-01

    The paper develops two-dimensional (2D), nonseparable, piecewise cubic convolution (PCC) for image interpolation. Traditionally, PCC has been implemented based on a one-dimensional (1D) derivation with a separable generalization to two dimensions. However, typical scenes and imaging systems are not separable, so the traditional approach is suboptimal. We develop a closed-form derivation for a two-parameter, 2D PCC kernel with support [-2,2] x [-2,2] that is constrained for continuity, smoothness, symmetry, and flat-field response. Our analyses, using several image models, including Markov random fields, demonstrate that the 2D PCC yields small improvements in interpolation fidelity over the traditional, separable approach. The constraints on the derivation can be relaxed to provide greater flexibility and performance.

  18. Oscillations in the spectrum of nonlinear Thomson-backscattered radiation

    Directory of Open Access Journals (Sweden)

    C. A. Brau

    2004-02-01

    Full Text Available When an electron beam collides with a high-intensity laser beam, the spectrum of the nonlinear Thomson scattering in the backward direction shows strong oscillations like those in the spectrum of an optical klystron. Laser gain on the backward Thomson scattering is estimated using the Madey theorem, and the results suggest that Thomson-backscatter free-electron lasers are possible at wavelengths extending to the far uv using a terawatt laser beam from a chirped-pulse amplifier and a high-brightness electron beam from a needle cathode.

  19. Classifying Two-dimensional Hyporeductive Triple Algebras

    CERN Document Server

    Issa, A Nourou

    2010-01-01

    Two-dimensional real hyporeductive triple algebras (h.t.a.) are investigated. A classification of such algebras is presented. As a consequence, a classification of two-dimensional real Lie triple algebras (i.e. generalized Lie triple systems) and two-dimensional real Bol algebras is given.

  20. Two-dimensional function photonic crystals

    CERN Document Server

    Wu, Xiang-Yao; Liu, Xiao-Jing; Liang, Yu

    2016-01-01

    In this paper, we have firstly proposed two-dimensional function photonic crystals, which the dielectric constants of medium columns are the functions of space coordinates $\\vec{r}$, it is different from the two-dimensional conventional photonic crystals constituting by the medium columns of dielectric constants are constants. We find the band gaps of two-dimensional function photonic crystals are different from the two-dimensional conventional photonic crystals, and when the functions form of dielectric constants are different, the band gaps structure should be changed, which can be designed into the appropriate band gaps structures by the two-dimensional function photonic crystals.

  1. Inelastic X-Ray Scattering from Shocked Liquid Deuterium

    Science.gov (United States)

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B. J. B.; Glenzer, S. H.; Landen, O. L.; Gericke, D. O.; Döppner, T.; Meyerhofer, D. D.; Murphy, C. D.; Sangster, T. C.; Vorberger, J.

    2012-12-01

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. These first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5eV, an electron density of 2.2(±0.5)×1023cm-3, and an ionization of 0.8 (-0.25, +0.15). Two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  2. Critical Behaviour of a Two-Dimensional Random Antiferromagnet

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage; Birgeneau, R. J.; Guggenheim, H. J.

    1976-01-01

    A neutron scattering study of the order parameter, correlation length and staggered susceptibility of the two-dimensional random antiferromagnet Rb2Mn0.5Ni0.5F4 is reported. The system is found to exhibit a well-defined phase transition with critical exponents identical to those of the isomorphou...... pure materials K2NiF4 and K2MnF4. Thus, in these systems, which have the asymptotic critical behaviour of the two-dimensional Ising model, randomness has no measurable effect on the phase-transition behaviour....

  3. Imperfect two-dimensional topological insulator field-effect transistors

    Science.gov (United States)

    Vandenberghe, William G.; Fischetti, Massimo V.

    2017-01-01

    To overcome the challenge of using two-dimensional materials for nanoelectronic devices, we propose two-dimensional topological insulator field-effect transistors that switch based on the modulation of scattering. We model transistors made of two-dimensional topological insulator ribbons accounting for scattering with phonons and imperfections. In the on-state, the Fermi level lies in the bulk bandgap and the electrons travel ballistically through the topologically protected edge states even in the presence of imperfections. In the off-state the Fermi level moves into the bandgap and electrons suffer from severe back-scattering. An off-current more than two-orders below the on-current is demonstrated and a high on-current is maintained even in the presence of imperfections. At low drain-source bias, the output characteristics are like those of conventional field-effect transistors, at large drain-source bias negative differential resistance is revealed. Complementary n- and p-type devices can be made enabling high-performance and low-power electronic circuits using imperfect two-dimensional topological insulators. PMID:28106059

  4. Hadamard States and Two-dimensional Gravity

    CERN Document Server

    Salehi, H

    2001-01-01

    We have used a two-dimensional analog of the Hadamard state-condition to study the local constraints on the two-point function of a linear quantum field conformally coupled to a two-dimensional gravitational background. We develop a dynamical model in which the determination of the state of the quantum field is essentially related to the determination of a conformal frame. A particular conformal frame is then introduced in which a two-dimensional gravitational equation is established.

  5. Topological defects in two-dimensional crystals

    OpenAIRE

    Chen, Yong; Qi, Wei-Kai

    2008-01-01

    By using topological current theory, we study the inner topological structure of the topological defects in two-dimensional (2D) crystal. We find that there are two elementary point defects topological current in two-dimensional crystal, one for dislocations and the other for disclinations. The topological quantization and evolution of topological defects in two-dimensional crystals are discussed. Finally, We compare our theory with Brownian-dynamics simulations in 2D Yukawa systems.

  6. Dual color x-rays from Thomson or Compton sources

    Science.gov (United States)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Ferrario, M.; Maroli, C.; Rau, J. V.; Ronsivalle, C.; Serafini, L.; Vaccarezza, C.; Venturelli, M.

    2015-05-01

    We analyze the possibility of producing two color X or γ radiation by Thomson/Compton back-scattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of values for a realistic experiments.

  7. Strongly interacting two-dimensional Dirac fermions

    NARCIS (Netherlands)

    Lim, L.K.; Lazarides, A.; Hemmerich, Andreas; de Morais Smith, C.

    2009-01-01

    We show how strongly interacting two-dimensional Dirac fermions can be realized with ultracold atoms in a two-dimensional optical square lattice with an experimentally realistic, inherent gauge field, which breaks time reversal and inversion symmetries. We find remarkable phenomena in a temperature

  8. Topology optimization of two-dimensional waveguides

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Sigmund, Ole

    2003-01-01

    In this work we use the method of topology optimization to design two-dimensional waveguides with low transmission loss.......In this work we use the method of topology optimization to design two-dimensional waveguides with low transmission loss....

  9. Thomson Scattering for Determining Electron Concentrations and Temperatures in an Inductively Coupled Plasma. 1. Assessment of the Technique for a Lo -Flow, Low-Power Plasma.

    Science.gov (United States)

    1988-02-15

    is the spectral density function which describes the frequency dependence of the scattering spectrum. If the electrons in the scattering volume are...stationary, no Doppler shift occurs and the spectral density function is 1 at (w=O (no frequency ,,diihit) and ;zero at all other frequencies. Of...electrons moving in a hot plasma. The spectral density function , which describes this Doppler- shifted spectrum, is very complicated and a description of it

  10. Two Dimensional Plasmonic Cavities on Moire Surfaces

    Science.gov (United States)

    Balci, Sinan; Kocabas, Askin; Karabiyik, Mustafa; Kocabas, Coskun; Aydinli, Atilla

    2010-03-01

    We investigate surface plasmon polariton (SPP) cavitiy modes on two dimensional Moire surfaces in the visible spectrum. Two dimensional hexagonal Moire surface can be recorded on a photoresist layer using Interference lithography (IL). Two sequential exposures at slightly different angles in IL generate one dimensional Moire surfaces. Further sequential exposure for the same sample at slightly different angles after turning the sample 60 degrees around its own axis generates two dimensional hexagonal Moire cavity. Spectroscopic reflection measurements have shown plasmonic band gaps and cavity states at all the azimuthal angles (omnidirectional cavity and band gap formation) investigated. The plasmonic band gap edge and the cavity states energies show six fold symmetry on the two dimensional Moire surface as measured in reflection measurements.

  11. Two-dimensional function photonic crystals

    Science.gov (United States)

    Liu, Xiao-Jing; Liang, Yu; Ma, Ji; Zhang, Si-Qi; Li, Hong; Wu, Xiang-Yao; Wu, Yi-Heng

    2017-01-01

    In this paper, we have studied two-dimensional function photonic crystals, in which the dielectric constants of medium columns are the functions of space coordinates , that can become true easily by electro-optical effect and optical kerr effect. We calculated the band gap structures of TE and TM waves, and found the TE (TM) wave band gaps of function photonic crystals are wider (narrower) than the conventional photonic crystals. For the two-dimensional function photonic crystals, when the dielectric constant functions change, the band gaps numbers, width and position should be changed, and the band gap structures of two-dimensional function photonic crystals can be adjusted flexibly, the needed band gap structures can be designed by the two-dimensional function photonic crystals, and it can be of help to design optical devices.

  12. Two-Dimensional Planetary Surface Lander

    Science.gov (United States)

    Hemmati, H.; Sengupta, A.; Castillo, J.; McElrath, T.; Roberts, T.; Willis, P.

    2014-06-01

    A systems engineering study was conducted to leverage a new two-dimensional (2D) lander concept with a low per unit cost to enable scientific study at multiple locations with a single entry system as the delivery vehicle.

  13. Comparing natural and artificial carious lesions in human crowns by means of conventional hard x-ray micro-tomography and two-dimensional x-ray scattering with synchrotron radiation

    Science.gov (United States)

    Botta, Lea Maria; White, Shane N.; Deyhle, Hans; Dziadowiec, Iwona; Schulz, Georg; Thalmann, Peter; Müller, Bert

    2016-10-01

    Dental caries, one of the most prevalent infectious bacterial diseases in the world, is caused by specific types of acid-producing bacteria. Caries is a disease continuum resulting from the earliest loss of ions from apatite crystals through gross cavitation. Enamel dissolution starts when the pH-value drops below 5.5. Neutralizing the pH-value in the oral cavity opposes the process of demineralization, and so caries lesions occur in a dynamic cyclic de-mineralizing/remineralizing environment. Unfortunately, biomimetic regeneration of cavitated enamel is not yet possible, although remineralization of small carious lesions occurs under optimal conditions. Therefore, the development of methods that can regenerate carious lesions, and subsequently recover and retain teeth, is highly desirable. For the present proceedings we analyzed one naturally occurring sub-surface and one artificially produced lesion. For the characterization of artificial and natural lesions micro computed tomography is the method of choice when looking to determine three-dimensional mineral distribution and to quantify the degree of mineralization. In this pilot study we elucidate that the de-mineralized enamel in natural and artificially induced lesions shows comparable X-ray attenuation behavior, thereby implying that the study protocol employed herein seems to be appropriate. Once we know that the lesions are comparable, a series of well-reproducible in vitro experiments on enamel regeneration could be performed. In order to quantify further lesion morphology, the anisotropy of the enamel's nanostructure can be characterized by using spatially resolved, small-angle X-ray scattering. We wanted to demonstrate that the artificially induced defect fittingly resembles the natural carious lesion.

  14. Interpolation by two-dimensional cubic convolution

    Science.gov (United States)

    Shi, Jiazheng; Reichenbach, Stephen E.

    2003-08-01

    This paper presents results of image interpolation with an improved method for two-dimensional cubic convolution. Convolution with a piecewise cubic is one of the most popular methods for image reconstruction, but the traditional approach uses a separable two-dimensional convolution kernel that is based on a one-dimensional derivation. The traditional, separable method is sub-optimal for the usual case of non-separable images. The improved method in this paper implements the most general non-separable, two-dimensional, piecewise-cubic interpolator with constraints for symmetry, continuity, and smoothness. The improved method of two-dimensional cubic convolution has three parameters that can be tuned to yield maximal fidelity for specific scene ensembles characterized by autocorrelation or power-spectrum. This paper illustrates examples for several scene models (a circular disk of parametric size, a square pulse with parametric rotation, and a Markov random field with parametric spatial detail) and actual images -- presenting the optimal parameters and the resulting fidelity for each model. In these examples, improved two-dimensional cubic convolution is superior to several other popular small-kernel interpolation methods.

  15. The SPARC-LAB Thomson source

    Energy Technology Data Exchange (ETDEWEB)

    Vaccarezza, C., E-mail: cristina.vaccarezza@lnf.infn.it [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Alesini, D.; Anania, M.P. [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Bacci, A. [INFN-MI, Via Celoria 16, 20133 Milan (Italy); Biagioni, A.; Bisesto, F.; Bellaveglia, M. [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Cardarelli, P. [University of Ferrara and INFN-FE, via Saragat 1, 44122 Ferrara (Italy); Cardelli, F. [University La Sapienza and INFN-Roma1, Piazzale Aldo Moro, 2 00161 Rome (Italy); Cianchi, A. [University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Chiadroni, E.; Croia, M.; Curcio, A. [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Delogu, P. [University of Pisa and INFN-PI, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Giovenale, D. Di [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Domenico, G. Di [University of Ferrara and INFN-FE, via Saragat 1, 44122 Ferrara (Italy); Pirro, G. Di [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Drebot, I. [INFN-MI, Via Celoria 16, 20133 Milan (Italy); Ferrario, M. [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Filippi, F. [University La Sapienza and INFN-Roma1, Piazzale Aldo Moro, 2 00161 Rome (Italy); and others

    2016-09-01

    The SPARC-LAB Thomson source is a compact X-ray source based on the Thomson backscattering process presently under its second phase of commissioning at the LNF. The electron beam energy ranges between 30 and 150 MeV, the electrons collide head-on with the Ti:Sapphire FLAME laser pulse the energy of which ranges between 1 and 5 J with pulse lengths in the 25 fs–10 ps range, this provides an X-ray energy tunability in the range of 20–500 keV, with the further capability to generate strongly non-linear phenomena and to drive diffusion processes due to multiple and plural scattering effects. The experimental results of the obtained X-ray radiation are presented.

  16. The SPARC_LAB Thomson source

    Science.gov (United States)

    Vaccarezza, C.; Alesini, D.; Anania, M. P.; Bacci, A.; Biagioni, A.; Bisesto, F.; Bellaveglia, M.; Cardarelli, P.; Cardelli, F.; Cianchi, A.; Chiadroni, E.; Croia, M.; Curcio, A.; Delogu, P.; Giovenale, D. Di; Domenico, G. Di; Pirro, G. Di; Drebot, I.; Ferrario, M.; Filippi, F.; Gallo, A.; Galletti, M.; Gambaccini, M.; Giribono, A.; Golosio, B.; Li, W.; Mostacci, A.; Oliva, P.; Palmer, D.; Petrillo, V.; Petrarca, M.; Pioli, S.; Piersanti, L.; Pompili, R.; Romeo, S.; Rossi, A. R.; Scifo, J.; Serafini, L.; Suliman, G.; Villa, F.

    2016-09-01

    The SPARC_LAB Thomson source is a compact X-ray source based on the Thomson backscattering process presently under its second phase of commissioning at the LNF. The electron beam energy ranges between 30 and 150 MeV, the electrons collide head-on with the Ti:Sapphire FLAME laser pulse the energy of which ranges between 1 and 5 J with pulse lengths in the 25 fs-10 ps range, this provides an X-ray energy tunability in the range of 20-500 keV, with the further capability to generate strongly non-linear phenomena and to drive diffusion processes due to multiple and plural scattering effects. The experimental results of the obtained X-ray radiation are presented.

  17. TWO-DIMENSIONAL TOPOLOGY OF COSMOLOGICAL REIONIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yougang; Xu, Yidong; Chen, Xuelei [Key Laboratory of Computational Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 China (China); Park, Changbom [School of Physics, Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 130-722 (Korea, Republic of); Kim, Juhan, E-mail: wangyg@bao.ac.cn, E-mail: cbp@kias.re.kr [Center for Advanced Computation, Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 130-722 (Korea, Republic of)

    2015-11-20

    We study the two-dimensional topology of the 21-cm differential brightness temperature for two hydrodynamic radiative transfer simulations and two semi-numerical models. In each model, we calculate the two-dimensional genus curve for the early, middle, and late epochs of reionization. It is found that the genus curve depends strongly on the ionized fraction of hydrogen in each model. The genus curves are significantly different for different reionization scenarios even when the ionized faction is the same. We find that the two-dimensional topology analysis method is a useful tool to constrain the reionization models. Our method can be applied to the future observations such as those of the Square Kilometre Array.

  18. Two dimensional topology of cosmological reionization

    CERN Document Server

    Wang, Yougang; Xu, Yidong; Chen, Xuelei; Kim, Juhan

    2015-01-01

    We study the two-dimensional topology of the 21-cm differential brightness temperature for two hydrodynamic radiative transfer simulations and two semi-numerical models. In each model, we calculate the two dimensional genus curve for the early, middle and late epochs of reionization. It is found that the genus curve depends strongly on the ionized fraction of hydrogen in each model. The genus curves are significantly different for different reionization scenarios even when the ionized faction is the same. We find that the two-dimensional topology analysis method is a useful tool to constrain the reionization models. Our method can be applied to the future observations such as those of the Square Kilometer Array.

  19. Two-dimensional x-ray diffraction

    CERN Document Server

    He, Bob B

    2009-01-01

    Written by one of the pioneers of 2D X-Ray Diffraction, this useful guide covers the fundamentals, experimental methods and applications of two-dimensional x-ray diffraction, including geometry convention, x-ray source and optics, two-dimensional detectors, diffraction data interpretation, and configurations for various applications, such as phase identification, texture, stress, microstructure analysis, crystallinity, thin film analysis and combinatorial screening. Experimental examples in materials research, pharmaceuticals, and forensics are also given. This presents a key resource to resea

  20. Matching Two-dimensional Gel Electrophoresis' Spots

    DEFF Research Database (Denmark)

    Dos Anjos, António; AL-Tam, Faroq; Shahbazkia, Hamid Reza

    2012-01-01

    This paper describes an approach for matching Two-Dimensional Electrophoresis (2-DE) gels' spots, involving the use of image registration. The number of false positive matches produced by the proposed approach is small, when compared to academic and commercial state-of-the-art approaches. This ar......This paper describes an approach for matching Two-Dimensional Electrophoresis (2-DE) gels' spots, involving the use of image registration. The number of false positive matches produced by the proposed approach is small, when compared to academic and commercial state-of-the-art approaches...

  1. Towards two-dimensional search engines

    OpenAIRE

    Ermann, Leonardo; Chepelianskii, Alexei D.; Shepelyansky, Dima L.

    2011-01-01

    We study the statistical properties of various directed networks using ranking of their nodes based on the dominant vectors of the Google matrix known as PageRank and CheiRank. On average PageRank orders nodes proportionally to a number of ingoing links, while CheiRank orders nodes proportionally to a number of outgoing links. In this way the ranking of nodes becomes two-dimensional that paves the way for development of two-dimensional search engines of new type. Statistical properties of inf...

  2. Field analysis of two-dimensional integrated optical gratings

    Science.gov (United States)

    Borsboom, P.-P.; Frankena, H. J.

    1995-05-01

    A rigorous technique to determine the field scattered by a two-dimensional rectangular grating made up of many corrugations was developed. In this method, the grating was deemed as a sequence of two types of waveguide sections, alternatingly connected by step discontinuities. A matrix was derived that described the entire rectangular grating by integrating the separate steps and waveguide sections. With the proposed technique, several configuration were analyzed. The obtained results showed good consistency with the consequences of previous studies. Furthermore, to examine the numerical stability of the proposed method, the length of the grating was increased and obtained results for a grating with 100 periods.

  3. Quantum skyrmions in two-dimensional chiral magnets

    Science.gov (United States)

    Takashima, Rina; Ishizuka, Hiroaki; Balents, Leon

    2016-10-01

    We study the quantum mechanics of magnetic skyrmions in the vicinity of the skyrmion-crystal to ferromagnet phase boundary in two-dimensional magnets. We show that the skyrmion excitation has an energy dispersion that splits into multiple bands due to the combination of magnus force and the underlying lattice. Condensation of the skyrmions can give rise to an intermediate phase between the skyrmion crystal and ferromagnet: a quantum liquid, in which skyrmions are not spatially localized. We show that the critical behavior depends on the spin size S and the topological number of the skyrmion. Experimental signatures of quantum skyrmions in inelastic neutron-scattering measurements are also discussed.

  4. Piezoelectricity in Two-Dimensional Materials

    KAUST Repository

    Wu, Tao

    2015-02-25

    Powering up 2D materials: Recent experimental studies confirmed the existence of piezoelectricity - the conversion of mechanical stress into electricity - in two-dimensional single-layer MoS2 nanosheets. The results represent a milestone towards embedding low-dimensional materials into future disruptive technologies. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

  5. Kronecker Product of Two-dimensional Arrays

    Institute of Scientific and Technical Information of China (English)

    Lei Hu

    2006-01-01

    Kronecker sequences constructed from short sequences are good sequences for spread spectrum communication systems. In this paper we study a similar problem for two-dimensional arrays, and we determine the linear complexity of the Kronecker product of two arrays. Our result shows that similar good property on linear complexity holds for Kronecker product of arrays.

  6. Two-Dimensional Toda-Heisenberg Lattice

    Directory of Open Access Journals (Sweden)

    Vadim E. Vekslerchik

    2013-06-01

    Full Text Available We consider a nonlinear model that is a combination of the anisotropic two-dimensional classical Heisenberg and Toda-like lattices. In the framework of the Hirota direct approach, we present the field equations of this model as a bilinear system, which is closely related to the Ablowitz-Ladik hierarchy, and derive its N-soliton solutions.

  7. A novel two dimensional particle velocity sensor

    NARCIS (Netherlands)

    Pjetri, Olti; Wiegerink, Remco J.; Lammerink, Theo S.; Krijnen, Gijs J.

    2013-01-01

    In this paper we present a two wire, two-dimensional particle velocity sensor. The miniature sensor of size 1.0x2.5x0.525 mm, consisting of only two crossed wires, shows excellent directional sensitivity in both directions, thus requiring no directivity calibration, and is relatively easy to fabrica

  8. Two-dimensional microstrip detector for neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Oed, A. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Because of their robust design, gas microstrip detectors, which were developed at ILL, can be assembled relatively quickly, provided the prefabricated components are available. At the beginning of 1996, orders were received for the construction of three two-dimensional neutron detectors. These detectors have been completed. The detectors are outlined below. (author). 2 refs.

  9. Two-dimensional magma-repository interactions

    NARCIS (Netherlands)

    Bokhove, O.

    2001-01-01

    Two-dimensional simulations of magma-repository interactions reveal that the three phases --a shock tube, shock reflection and amplification, and shock attenuation and decay phase-- in a one-dimensional flow tube model have a precursor. This newly identified phase ``zero'' consists of the impact of

  10. Two-dimensional subwavelength plasmonic lattice solitons

    CERN Document Server

    Ye, F; Hu, B; Panoiu, N C

    2010-01-01

    We present a theoretical study of plasmonic lattice solitons (PLSs) formed in two-dimensional (2D) arrays of metallic nanowires embedded into a nonlinear medium with Kerr nonlinearity. We analyze two classes of 2D PLSs families, namely, fundamental and vortical PLSs in both focusing and defocusing media. Their existence, stability, and subwavelength spatial confinement are studied in detai

  11. A two-dimensional Dirac fermion microscope

    DEFF Research Database (Denmark)

    Bøggild, Peter; Caridad, Jose; Stampfer, Christoph

    2017-01-01

    in the solid state. Here we provide a perspective view on how a two-dimensional (2D) Dirac fermion-based microscope can be realistically implemented and operated, using graphene as a vacuum chamber for ballistic electrons. We use semiclassical simulations to propose concrete architectures and design rules of 2...

  12. Low-Frequency Scattering from Two-Dimensional Perfect Conductors

    Science.gov (United States)

    1991-04-01

    jkr ! G(f, f’)K.(f’)ds’, f E S (2.6) where the bar on the integral sign indicates that the singularity at f = f’ is excluded. From the small...2.17) is O~n’ 𔃼 7 The bar on the integral sign indicates that this is a Cauchy principal value integration. To determine the low-frequency expansion

  13. Electron Scattering in Two-Dimensional Disordered Heterostructures

    Science.gov (United States)

    2002-01-01

    8217Departamento de Fisica de Materiales , Universidad Complutense, E-20840 Madrid, Spain 2Departamento de Ffsica, Universidad Cat6lica del Norte, Casilla...ICM P99-135-F and Cdtedra Presidencial de Ciencias for financial support. REFERENCES 1. U. Penner, H. Raicker, and I. N. Yassievich, Semicond. Sci

  14. Optical properties of two-dimensional magnetoelectric point scattering lattices

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann; Sersic, Ivana; Koenderink, A. Femius

    2013-01-01

    of split ring resonators and provide a quantitative comparison of measured and calculated transmission spectra at normal incidence as a function of lattice density, showing excellent agreement. We further show angle-dependent transmission calculations for circularly polarized light and compare...

  15. Bobina de Thomson

    Directory of Open Access Journals (Sweden)

    Horacio Munguía Aguilar

    2014-12-01

    Full Text Available Uno de los instrumentos más didácticos en la enseñanza de las leyes del electromagnetismo es la denominada Bobina de Thomson. Con ella se pueden realizar diferentes experimentos sobre las leyes de Ampere y Faraday. En el presente trabajo se muestra su funcionamiento, se explica el mecanismo de levitación del anillo de inducción, se presenta los detalles de un modelo construido y se mencionan otros experimentos que enriquecen su funcionalidad.

  16. Bobina de Thomson

    OpenAIRE

    2014-01-01

    Uno de los instrumentos más didácticos en la enseñanza de las leyes del electromagnetismo es la denominada Bobina de Thomson. Con ella se pueden realizar diferentes experimentos sobre las leyes de Ampere y Faraday. En el presente trabajo se muestra su funcionamiento, se explica el mecanismo de levitación del anillo de inducción, se presenta los detalles de un modelo construido y se mencionan otros experimentos que enriquecen su funcionalidad.

  17. Cycling Joule Thomson refrigerator

    Science.gov (United States)

    Tward, E.

    1983-01-01

    A symmetrical adsorption pump/compressor system having a pair of mirror image legs and a Joule Thomson expander, or valve, interposed between the legs thereof for providing a, efficient refrigeration cycle is described. The system further includes a plurality of gas operational heat switches adapted selectively to transfer heat from a thermal load and to transfer or discharge heat through a heat projector, such as a radiator or the like. The heat switches comprise heat pressurizable chambers adapted for alternate pressurization in response to adsorption and desorption of a pressurizing gas confined therein.

  18. Electronics based on two-dimensional materials.

    Science.gov (United States)

    Fiori, Gianluca; Bonaccorso, Francesco; Iannaccone, Giuseppe; Palacios, Tomás; Neumaier, Daniel; Seabaugh, Alan; Banerjee, Sanjay K; Colombo, Luigi

    2014-10-01

    The compelling demand for higher performance and lower power consumption in electronic systems is the main driving force of the electronics industry's quest for devices and/or architectures based on new materials. Here, we provide a review of electronic devices based on two-dimensional materials, outlining their potential as a technological option beyond scaled complementary metal-oxide-semiconductor switches. We focus on the performance limits and advantages of these materials and associated technologies, when exploited for both digital and analog applications, focusing on the main figures of merit needed to meet industry requirements. We also discuss the use of two-dimensional materials as an enabling factor for flexible electronics and provide our perspectives on future developments.

  19. Two-dimensional ranking of Wikipedia articles

    Science.gov (United States)

    Zhirov, A. O.; Zhirov, O. V.; Shepelyansky, D. L.

    2010-10-01

    The Library of Babel, described by Jorge Luis Borges, stores an enormous amount of information. The Library exists ab aeterno. Wikipedia, a free online encyclopaedia, becomes a modern analogue of such a Library. Information retrieval and ranking of Wikipedia articles become the challenge of modern society. While PageRank highlights very well known nodes with many ingoing links, CheiRank highlights very communicative nodes with many outgoing links. In this way the ranking becomes two-dimensional. Using CheiRank and PageRank we analyze the properties of two-dimensional ranking of all Wikipedia English articles and show that it gives their reliable classification with rich and nontrivial features. Detailed studies are done for countries, universities, personalities, physicists, chess players, Dow-Jones companies and other categories.

  20. Two-Dimensional NMR Lineshape Analysis

    Science.gov (United States)

    Waudby, Christopher A.; Ramos, Andres; Cabrita, Lisa D.; Christodoulou, John

    2016-04-01

    NMR titration experiments are a rich source of structural, mechanistic, thermodynamic and kinetic information on biomolecular interactions, which can be extracted through the quantitative analysis of resonance lineshapes. However, applications of such analyses are frequently limited by peak overlap inherent to complex biomolecular systems. Moreover, systematic errors may arise due to the analysis of two-dimensional data using theoretical frameworks developed for one-dimensional experiments. Here we introduce a more accurate and convenient method for the analysis of such data, based on the direct quantum mechanical simulation and fitting of entire two-dimensional experiments, which we implement in a new software tool, TITAN (TITration ANalysis). We expect the approach, which we demonstrate for a variety of protein-protein and protein-ligand interactions, to be particularly useful in providing information on multi-step or multi-component interactions.

  1. Towards two-dimensional search engines

    CERN Document Server

    Ermann, Leonardo; Shepelyansky, Dima L

    2011-01-01

    We study the statistical properties of various directed networks using ranking of their nodes based on the dominant vectors of the Google matrix known as PageRank and CheiRank. On average PageRank orders nodes proportionally to a number of ingoing links, while CheiRank orders nodes proportionally to a number of outgoing links. In this way the ranking of nodes becomes two-dimensional that paves the way for development of two-dimensional search engines of new type. Information flow properties on PageRank-CheiRank plane are analyzed for networks of British, French and Italian Universities, Wikipedia, Linux Kernel, gene regulation and other networks. Methods of spam links control are also analyzed.

  2. Toward two-dimensional search engines

    Science.gov (United States)

    Ermann, L.; Chepelianskii, A. D.; Shepelyansky, D. L.

    2012-07-01

    We study the statistical properties of various directed networks using ranking of their nodes based on the dominant vectors of the Google matrix known as PageRank and CheiRank. On average PageRank orders nodes proportionally to a number of ingoing links, while CheiRank orders nodes proportionally to a number of outgoing links. In this way, the ranking of nodes becomes two dimensional which paves the way for the development of two-dimensional search engines of a new type. Statistical properties of information flow on the PageRank-CheiRank plane are analyzed for networks of British, French and Italian universities, Wikipedia, Linux Kernel, gene regulation and other networks. A special emphasis is done for British universities networks using the large database publicly available in the UK. Methods of spam links control are also analyzed.

  3. A two-dimensional Dirac fermion microscope

    Science.gov (United States)

    Bøggild, Peter; Caridad, José M.; Stampfer, Christoph; Calogero, Gaetano; Papior, Nick Rübner; Brandbyge, Mads

    2017-06-01

    The electron microscope has been a powerful, highly versatile workhorse in the fields of material and surface science, micro and nanotechnology, biology and geology, for nearly 80 years. The advent of two-dimensional materials opens new possibilities for realizing an analogy to electron microscopy in the solid state. Here we provide a perspective view on how a two-dimensional (2D) Dirac fermion-based microscope can be realistically implemented and operated, using graphene as a vacuum chamber for ballistic electrons. We use semiclassical simulations to propose concrete architectures and design rules of 2D electron guns, deflectors, tunable lenses and various detectors. The simulations show how simple objects can be imaged with well-controlled and collimated in-plane beams consisting of relativistic charge carriers. Finally, we discuss the potential of such microscopes for investigating edges, terminations and defects, as well as interfaces, including external nanoscale structures such as adsorbed molecules, nanoparticles or quantum dots.

  4. A two-dimensional Dirac fermion microscope.

    Science.gov (United States)

    Bøggild, Peter; Caridad, José M; Stampfer, Christoph; Calogero, Gaetano; Papior, Nick Rübner; Brandbyge, Mads

    2017-06-09

    The electron microscope has been a powerful, highly versatile workhorse in the fields of material and surface science, micro and nanotechnology, biology and geology, for nearly 80 years. The advent of two-dimensional materials opens new possibilities for realizing an analogy to electron microscopy in the solid state. Here we provide a perspective view on how a two-dimensional (2D) Dirac fermion-based microscope can be realistically implemented and operated, using graphene as a vacuum chamber for ballistic electrons. We use semiclassical simulations to propose concrete architectures and design rules of 2D electron guns, deflectors, tunable lenses and various detectors. The simulations show how simple objects can be imaged with well-controlled and collimated in-plane beams consisting of relativistic charge carriers. Finally, we discuss the potential of such microscopes for investigating edges, terminations and defects, as well as interfaces, including external nanoscale structures such as adsorbed molecules, nanoparticles or quantum dots.

  5. Two-Dimensional Scheduling: A Review

    Directory of Open Access Journals (Sweden)

    Zhuolei Xiao

    2013-07-01

    Full Text Available In this study, we present a literature review, classification schemes and analysis of methodology for scheduling problems on Batch Processing machine (BP with both processing time and job size constraints which is also regarded as Two-Dimensional (TD scheduling. Special attention is given to scheduling problems with non-identical job sizes and processing times, with details of the basic algorithms and other significant results.

  6. Two dimensional fermions in four dimensional YM

    CERN Document Server

    Narayanan, R

    2009-01-01

    Dirac fermions in the fundamental representation of SU(N) live on a two dimensional torus flatly embedded in $R^4$. They interact with a four dimensional SU(N) Yang Mills vector potential preserving a global chiral symmetry at finite $N$. As the size of the torus in units of $\\frac{1}{\\Lambda_{SU(N)}}$ is varied from small to large, the chiral symmetry gets spontaneously broken in the infinite $N$ limit.

  7. Two-dimensional Kagome photonic bandgap waveguide

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo; Søndergaard, Thomas; Libori, Stig E. Barkou;

    2000-01-01

    The transverse-magnetic photonic-bandgap-guidance properties are investigated for a planar two-dimensional (2-D) Kagome waveguide configuration using a full-vectorial plane-wave-expansion method. Single-moded well-localized low-index guided modes are found. The localization of the optical modes...... is investigated with respect to the width of the 2-D Kagome waveguide, and the number of modes existing for specific frequencies and waveguide widths is mapped out....

  8. String breaking in two-dimensional QCD

    CERN Document Server

    Hornbostel, K J

    1999-01-01

    I present results of a numerical calculation of the effects of light quark-antiquark pairs on the linear heavy-quark potential in light-cone quantized two-dimensional QCD. I extract the potential from the Q-Qbar component of the ground-state wavefunction, and observe string breaking at the heavy-light meson pair threshold. I briefly comment on the states responsible for the breaking.

  9. Two-dimensional supramolecular electron spin arrays.

    Science.gov (United States)

    Wäckerlin, Christian; Nowakowski, Jan; Liu, Shi-Xia; Jaggi, Michael; Siewert, Dorota; Girovsky, Jan; Shchyrba, Aneliia; Hählen, Tatjana; Kleibert, Armin; Oppeneer, Peter M; Nolting, Frithjof; Decurtins, Silvio; Jung, Thomas A; Ballav, Nirmalya

    2013-05-07

    A bottom-up approach is introduced to fabricate two-dimensional self-assembled layers of molecular spin-systems containing Mn and Fe ions arranged in a chessboard lattice. We demonstrate that the Mn and Fe spin states can be reversibly operated by their selective response to coordination/decoordination of volatile ligands like ammonia (NH3). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Two dimensional echocardiographic detection of intraatrial masses.

    Science.gov (United States)

    DePace, N L; Soulen, R L; Kotler, M N; Mintz, G S

    1981-11-01

    With two dimensional echocardiography, a left atrial mass was detected in 19 patients. Of these, 10 patients with rheumatic mitral stenosis had a left atrial thrombus. The distinctive two dimensional echocardiographic features of left atrial thrombus included a mass of irregular nonmobile laminated echos within an enlarged atrial cavity, usually with a broad base of attachment to the posterior left atrial wall. Seven patients had a left atrial myxoma. Usually, the myxoma appeared as a mottled ovoid, sharply demarcated mobile mass attached to the interatrial septum. One patient had a right atrial angiosarcoma that appeared as a nonmobile mass extending from the inferior vena caval-right atrial junction into the right atrial cavity. One patient had a left atrial leiomyosarcoma producing a highly mobile mass attached to the lateral wall of the left atrium. M mode echocardiography detected six of the seven myxomas, one thrombus and neither of the other tumors. Thus, two dimensional echocardiography appears to be the technique of choice in the detection, localization and differentiation of intraatrial masses.

  11. On final states of two-dimensional decaying turbulence

    Science.gov (United States)

    Yin, Z.

    2004-12-01

    Numerical and analytical studies of final states of two-dimensional (2D) decaying turbulence are carried out. The first part of this work is trying to give a definition for final states of 2D decaying turbulence. The functional relation of ω-ψ, which is frequently adopted as the characterization of those final states, is merely a sufficient but not necessary condition; moreover, it is not proper to use it as the definition. It is found that the method through the value of the effective area S covered by the scatter ω-ψ plot, initially suggested by Read, Rhines, and White ["Geostrophic scatter diagrams and potential vorticity dynamics," J. Atmos. Sci. 43, 3226 (1986)] is more general and suitable for the definition. Based on this concept, a definition is presented, which covers all existing results in late states of decaying 2D flows (including some previous unexplainable weird double-valued ω-ψ scatter plots). The remaining part of the paper is trying to further study 2D decaying turbulence with the assistance of this definition. Some numerical results, leading to "bar" final states and further verifying the predictive ability of statistical mechanics [Yin, Montgomery, and Clercx, "Alternative statistical-mechanical descriptions of decaying two-dimensional turbulence in terms of patches and points," Phys. Fluids 15, 1937 (2003)], are reported. It is realized that some simulations with narrow-band energy spectral initial conditions result in some final states that cannot be very well interpreted by the statistical theory (meanwhile, those final states are still in the scope of the definition).

  12. Critical Behaviour of Pure and Site-Random Two Dimensional Antiferromagnets

    DEFF Research Database (Denmark)

    Birgenau, R. J.; Als-Nielsen, Jens Aage; Shirane, G.

    1977-01-01

    Quasielastic neutron scattering studies of the static critical behavior in the two-dimensional antiferromagnets K2NiF4, K2MnF4, and Rb2Mn0.5Ni0.5F4 are reported. For T......Quasielastic neutron scattering studies of the static critical behavior in the two-dimensional antiferromagnets K2NiF4, K2MnF4, and Rb2Mn0.5Ni0.5F4 are reported. For T...

  13. Weakly disordered two-dimensional Frenkel excitons

    Science.gov (United States)

    Boukahil, A.; Zettili, Nouredine

    2004-03-01

    We report the results of studies of the optical properties of weakly disordered two- dimensional Frenkel excitons in the Coherent Potential Approximation (CPA). An approximate complex Green's function for a square lattice with nearest neighbor interactions is used in the self-consistent equation to determine the coherent potential. It is shown that the Density of States is very much affected by the logarithmic singularities in the Green's function. Our CPA results are in excellent agreement with previous investigations by Schreiber and Toyozawa using the Monte Carlo simulation.

  14. Two-dimensional photonic crystal surfactant detection.

    Science.gov (United States)

    Zhang, Jian-Tao; Smith, Natasha; Asher, Sanford A

    2012-08-07

    We developed a novel two-dimensional (2-D) crystalline colloidal array photonic crystal sensing material for the visual detection of amphiphilic molecules in water. A close-packed polystyrene 2-D array monolayer was embedded in a poly(N-isopropylacrylamide) (PNIPAAm)-based hydrogel film. These 2-D photonic crystals placed on a mirror show intense diffraction that enables them to be used for visual determination of analytes. Binding of surfactant molecules attaches ions to the sensor that swells the PNIPAAm-based hydrogel. The resulting increase in particle spacing red shifts the 2-D diffracted light. Incorporation of more hydrophobic monomers increases the sensitivity to surfactants.

  15. Theory of two-dimensional transformations

    OpenAIRE

    Kanayama, Yutaka J.; Krahn, Gary W.

    1998-01-01

    The article of record may be found at http://dx.doi.org/10.1109/70.720359 Robotics and Automation, IEEE Transactions on This paper proposes a new "heterogeneous" two-dimensional (2D) transformation group ___ to solve motion analysis/planning problems in robotics. In this theory, we use a 3×1 matrix to represent a transformation as opposed to a 3×3 matrix in the homogeneous formulation. First, this theory is as capable as the homogeneous theory, Because of the minimal size, its implement...

  16. Two-dimensional ranking of Wikipedia articles

    CERN Document Server

    Zhirov, A O; Shepelyansky, D L

    2010-01-01

    The Library of Babel, described by Jorge Luis Borges, stores an enormous amount of information. The Library exists {\\it ab aeterno}. Wikipedia, a free online encyclopaedia, becomes a modern analogue of such a Library. Information retrieval and ranking of Wikipedia articles become the challenge of modern society. We analyze the properties of two-dimensional ranking of all Wikipedia English articles and show that it gives their reliable classification with rich and nontrivial features. Detailed studies are done for countries, universities, personalities, physicists, chess players, Dow-Jones companies and other categories.

  17. Sums of two-dimensional spectral triples

    DEFF Research Database (Denmark)

    Christensen, Erik; Ivan, Cristina

    2007-01-01

    construct a sum of two dimensional modules which reflects some aspects of the topological dimensions of the compact metric space, but this will only give the metric back approximately. At the end we make an explicit computation of the last module for the unit interval in. The metric is recovered exactly......, the Dixmier trace induces a multiple of the Lebesgue integral but the growth of the number of eigenvalues is different from the one found for the standard differential operator on the unit interval....

  18. Binding energy of two-dimensional biexcitons

    DEFF Research Database (Denmark)

    Singh, Jai; Birkedal, Dan; Vadim, Lyssenko;

    1996-01-01

    Using a model structure for a two-dimensional (2D) biexciton confined in a quantum well, it is shown that the form of the Hamiltonian of the 2D biexciton reduces into that of an exciton. The binding energies and Bohr radii of a 2D biexciton in its various internal energy states are derived...... analytically using the fractional dimension approach. The ratio of the binding energy of a 2D biexciton to that of a 2D exciton is found to be 0.228, which agrees very well with the recent experimental value. The results of our approach are compared with those of earlier theories....

  19. Dynamics of film. [two dimensional continua theory

    Science.gov (United States)

    Zak, M.

    1979-01-01

    The general theory of films as two-dimensional continua are elaborated upon. As physical realizations of such a model this paper examines: inextensible films, elastic films, and nets. The suggested dynamic equations have enabled us to find out the characteristic speeds of wave propagation of the invariants of external and internal geometry and formulate the criteria of instability of their shape. Also included herein is a detailed account of the equation describing the film motions beyond the limits of the shape stability accompanied by the formation of wrinkles. The theory is illustrated by examples.

  20. Two-dimensional gauge theoretic supergravities

    Science.gov (United States)

    Cangemi, D.; Leblanc, M.

    1994-05-01

    We investigate two-dimensional supergravity theories, which can be built from a topological and gauge invariant action defined on an ordinary surface. One is the N = 1 supersymmetric extension of the Jackiw-Teitelboim model presented by Chamseddine in a superspace formalism. We complement the proof of Montano, Aoaki and Sonnenschein that this extension is topological and gauge invariant, based on the graded de Sitter algebra. Not only do the equations of motion correspond to the supergravity ones and do gauge transformations encompass local supersymmetries, but we also identify the ∫-theory with the superfield formalism action written by Chamseddine. Next, we show that the N = 1 supersymmetric extension of string-inspired two-dimensional dilaton gravity put forward by Park and Strominger cannot be written as a ∫-theory. As an alternative, we propose two topological and gauge theories that are based on a graded extension of the extended Poincaré algebra and satisfy a vanishing-curvature condition. Both models are supersymmetric extensions of the string-inspired dilaton gravity.

  1. Two-Dimensional Theory of Scientific Representation

    Directory of Open Access Journals (Sweden)

    A Yaghmaie

    2013-03-01

    Full Text Available Scientific representation is an interesting topic for philosophers of science, many of whom have recently explored it from different points of view. There are currently two competing approaches to the issue: cognitive and non-cognitive, and each of them claims its own merits over the other. This article tries to provide a hybrid theory of scientific representation, called Two-Dimensional Theory of Scientific Representation, which has the merits of the two accounts and is free of their shortcomings. To do this, we will argue that although scientific representation needs to use the notion of intentionality, such a notion is defined and realized in a simply structural form contrary to what cognitive approach says about intentionality. After a short introduction, the second part of the paper is devoted to introducing theories of scientific representation briefly. In the third part, the structural accounts of representation will be criticized. The next step is to introduce the two-dimensional theory which involves two key components: fixing and structural fitness. It will be argued that fitness is an objective and non-intentional relation, while fixing is intentional.

  2. Two-dimensional shape memory graphene oxide

    Science.gov (United States)

    Chang, Zhenyue; Deng, Junkai; Chandrakumara, Ganaka G.; Yan, Wenyi; Liu, Jefferson Zhe

    2016-06-01

    Driven by the increasing demand for micro-/nano-technologies, stimuli-responsive shape memory materials at nanoscale have recently attracted great research interests. However, by reducing the size of conventional shape memory materials down to approximately nanometre range, the shape memory effect diminishes. Here, using density functional theory calculations, we report the discovery of a shape memory effect in a two-dimensional atomically thin graphene oxide crystal with ordered epoxy groups, namely C8O. A maximum recoverable strain of 14.5% is achieved as a result of reversible phase transition between two intrinsically stable phases. Our calculations conclude co-existence of the two stable phases in a coherent crystal lattice, giving rise to the possibility of constructing multiple temporary shapes in a single material, thus, enabling highly desirable programmability. With an atomic thickness, excellent shape memory mechanical properties and electric field stimulus, the discovery of a two-dimensional shape memory graphene oxide opens a path for the development of exceptional micro-/nano-electromechanical devices.

  3. Existence and Stability of Two-Dimensional Compact-Like Discrete Breathers in Discrete Two-Dimensional Monatomic Square Lattices

    Institute of Scientific and Technical Information of China (English)

    XU Quan; TIAN Qiang

    2007-01-01

    Two-dimensional compact-like discrete breathers in discrete two-dimensional monatomic square lattices are investigated by discussing a generafized discrete two-dimensional monatomic model.It is proven that the twodimensional compact-like discrete breathers exist not only in two-dimensional soft Ф4 potentials but also in hard two-dimensional Ф4 potentials and pure two-dimensional K4 lattices.The measurements of the two-dimensional compact-like discrete breather cores in soft and hard two-dimensional Ф4 potential are determined by coupling parameter K4,while those in pure two-dimensional K4 lattices have no coupling with parameter K4.The stabilities of the two-dimensional compact-like discrete breathers correlate closely to the coupling parameter K4 and the boundary condition of lattices.

  4. ITER Fast Ion Collective Thomson Scattering

    DEFF Research Database (Denmark)

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

    for measurements of the confined fusion alpha particles in ITER set by the ITER team. Then we outline the considerations, which enter into the selection and evaluation of CTS systems. System definition includes choice of probe frequency, geometry of probe and receiver beam patterns and probe power, but ultimately...

  5. Two-dimensional electronic spectroscopy with birefringent wedges

    Energy Technology Data Exchange (ETDEWEB)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  6. Coherent two-dimensional spectroscopy of a Fano model

    CERN Document Server

    Poulsen, Felipe; Pullerits, Tõnu; Hansen, Thorsten

    2016-01-01

    The Fano lineshape arises from the interference of two excitation pathways to reach a continuum. Its generality has resulted in a tremendous success in explaining the lineshapes of many one-dimensional spectroscopies - absorption, emission, scattering, conductance, photofragmentation - applied to very varied systems - atoms, molecules, semiconductors and metals. Unravelling a spectroscopy into a second dimension reveals the relationship between states in addition to decongesting the spectra. Femtosecond-resolved two-dimensional electronic spectroscopy (2DES) is a four-wave mixing technique that measures the time-evolution of the populations, and coherences of excited states. It has been applied extensively to the dynamics of photosynthetic units, and more recently to materials with extended band-structures. In this letter, we solve the full time-dependent third-order response, measured in 2DES, of a Fano model and give the new system parameters that become accessible.

  7. Effective-range dependence of two-dimensional Fermi gases

    Science.gov (United States)

    Schonenberg, L. M.; Verpoort, P. C.; Conduit, G. J.

    2017-08-01

    The Feshbach resonance provides precise control over the scattering length and effective range of interactions between ultracold atoms. We propose the ultratransferable pseudopotential to model effective interaction ranges -1.5 ≤kF2Reff2≤0 , where Reff is the effective range and kF is the Fermi wave vector, describing narrow to broad Feshbach resonances. We develop a mean-field treatment and exploit the pseudopotential to perform a variational and diffusion Monte Carlo study of the ground state of the two-dimensional Fermi gas, reporting on the ground-state energy, contact, condensate fraction, momentum distribution, and pair-correlation functions as a function of the effective interaction range across the BEC-BCS crossover. The limit kF2Reff2→-∞ is a gas of bosons with zero binding energy, whereas ln(kFa )→-∞ corresponds to noninteracting bosons with infinite binding energy.

  8. Light transport and localization in two-dimensional correlated disorder

    CERN Document Server

    Conley, Gaurasundar M; Pratesi, Filippo; Vynck, Kevin; Wiersma, Diederik S

    2013-01-01

    Structural correlations in disordered media are known to affect significantly the propagation of waves. In this article, we theoretically investigate the transport and localization of light in two-dimensional photonic structures with short-range correlated disorder. The problem is tackled semi-analytically using the Baus-Colot model for the structure factor of correlated media and a modified independent scattering approximation. We find that short-range correlations make it possible to easily tune the transport mean free path by more than a factor of 2 and the related localization length over several orders of magnitude. This trend is confirmed by numerical finite-difference time-domain calculations. This study therefore shows that disorder engineering can offer fine control over light transport and localization in planar geometries, which may open new opportunities in both fundamental and applied photonics research.

  9. Optimal excitation of two dimensional Holmboe instabilities

    CERN Document Server

    Constantinou, Navid C

    2010-01-01

    Highly stratified shear layers are rendered unstable even at high stratifications by Holmboe instabilities when the density stratification is concentrated in a small region of the shear layer. These instabilities may cause mixing in highly stratified environments. However these instabilities occur in tongues for a limited range of parameters. We perform Generalized Stability analysis of the two dimensional perturbation dynamics of an inviscid Boussinesq stratified shear layer and show that Holmboe instabilities at high Richardson numbers can be excited by their adjoints at amplitudes that are orders of magnitude larger than by introducing initially the unstable mode itself. We also determine the optimal growth that obtains for parameters for which there is no instability. We find that there is potential for large transient growth regardless of whether the background flow is exponentially stable or not and that the characteristic structure of the Holmboe instability asymptotically emerges for parameter values ...

  10. Probabilistic Universality in two-dimensional Dynamics

    CERN Document Server

    Lyubich, Mikhail

    2011-01-01

    In this paper we continue to explore infinitely renormalizable H\\'enon maps with small Jacobian. It was shown in [CLM] that contrary to the one-dimensional intuition, the Cantor attractor of such a map is non-rigid and the conjugacy with the one-dimensional Cantor attractor is at most 1/2-H\\"older. Another formulation of this phenomenon is that the scaling structure of the H\\'enon Cantor attractor differs from its one-dimensional counterpart. However, in this paper we prove that the weight assigned by the canonical invariant measure to these bad spots tends to zero on microscopic scales. This phenomenon is called {\\it Probabilistic Universality}. It implies, in particular, that the Hausdorff dimension of the canonical measure is universal. In this way, universality and rigidity phenomena of one-dimensional dynamics assume a probabilistic nature in the two-dimensional world.

  11. Two-dimensional position sensitive neutron detector

    Indian Academy of Sciences (India)

    A M Shaikh; S S Desai; A K Patra

    2004-08-01

    A two-dimensional position sensitive neutron detector has been developed. The detector is a 3He + Kr filled multiwire proportional counter with charge division position readout and has a sensitive area of 345 mm × 345 mm, pixel size 5 mm × 5 mm, active depth 25 mm and is designed for efficiency of 70% for 4 Å neutrons. The detector is tested with 0.5 bar 3He + 1.5 bar krypton gas mixture in active chamber and 2 bar 4He in compensating chamber. The pulse height spectrum recorded at an anode potential of 2000 V shows energy resolution of ∼ 25% for the 764 keV peak. A spatial resolution of 8 mm × 6 mm is achieved. The detector is suitable for SANS studies in the range of 0.02–0.25 Å-1.

  12. Two-dimensional heterostructures for energy storage

    Science.gov (United States)

    Pomerantseva, Ekaterina; Gogotsi, Yury

    2017-07-01

    Two-dimensional (2D) materials provide slit-shaped ion diffusion channels that enable fast movement of lithium and other ions. However, electronic conductivity, the number of intercalation sites, and stability during extended cycling are also crucial for building high-performance energy storage devices. While individual 2D materials, such as graphene, show some of the required properties, none of them can offer all properties needed to maximize energy density, power density, and cycle life. Here we argue that stacking different 2D materials into heterostructured architectures opens an opportunity to construct electrodes that would combine the advantages of the individual building blocks while eliminating the associated shortcomings. We discuss characteristics of common 2D materials and provide examples of 2D heterostructured electrodes that showed new phenomena leading to superior electrochemical performance. We also consider electrode fabrication approaches and finally outline future steps to create 2D heterostructured electrodes that could greatly expand current energy storage technologies.

  13. Rationally synthesized two-dimensional polymers.

    Science.gov (United States)

    Colson, John W; Dichtel, William R

    2013-06-01

    Synthetic polymers exhibit diverse and useful properties and influence most aspects of modern life. Many polymerization methods provide linear or branched macromolecules, frequently with outstanding functional-group tolerance and molecular weight control. In contrast, extending polymerization strategies to two-dimensional periodic structures is in its infancy, and successful examples have emerged only recently through molecular framework, surface science and crystal engineering approaches. In this Review, we describe successful 2D polymerization strategies, as well as seminal research that inspired their development. These methods include the synthesis of 2D covalent organic frameworks as layered crystals and thin films, surface-mediated polymerization of polyfunctional monomers, and solid-state topochemical polymerizations. Early application targets of 2D polymers include gas separation and storage, optoelectronic devices and membranes, each of which might benefit from predictable long-range molecular organization inherent to this macromolecular architecture.

  14. Janus Spectra in Two-Dimensional Flows

    Science.gov (United States)

    Liu, Chien-Chia; Cerbus, Rory T.; Chakraborty, Pinaki

    2016-09-01

    In large-scale atmospheric flows, soap-film flows, and other two-dimensional flows, the exponent of the turbulent energy spectra, α , may theoretically take either of two distinct values, 3 or 5 /3 , but measurements downstream of obstacles have invariably revealed α =3 . Here we report experiments on soap-film flows where downstream of obstacles there exists a sizable interval in which α transitions from 3 to 5 /3 for the streamwise fluctuations but remains equal to 3 for the transverse fluctuations, as if two mutually independent turbulent fields of disparate dynamics were concurrently active within the flow. This species of turbulent energy spectra, which we term the Janus spectra, has never been observed or predicted theoretically. Our results may open up new vistas in the study of turbulence and geophysical flows.

  15. Local doping of two-dimensional materials

    Science.gov (United States)

    Wong, Dillon; Velasco, Jr, Jairo; Ju, Long; Kahn, Salman; Lee, Juwon; Germany, Chad E.; Zettl, Alexander K.; Wang, Feng; Crommie, Michael F.

    2016-09-20

    This disclosure provides systems, methods, and apparatus related to locally doping two-dimensional (2D) materials. In one aspect, an assembly including a substrate, a first insulator disposed on the substrate, a second insulator disposed on the first insulator, and a 2D material disposed on the second insulator is formed. A first voltage is applied between the 2D material and the substrate. With the first voltage applied between the 2D material and the substrate, a second voltage is applied between the 2D material and a probe positioned proximate the 2D material. The second voltage between the 2D material and the probe is removed. The first voltage between the 2D material and the substrate is removed. A portion of the 2D material proximate the probe when the second voltage was applied has a different electron density compared to a remainder of the 2D material.

  16. Two-dimensional fourier transform spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    DeFlores, Lauren; Tokmakoff, Andrei

    2016-10-25

    The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

  17. Two-dimensional fourier transform spectrometer

    Science.gov (United States)

    DeFlores, Lauren; Tokmakoff, Andrei

    2013-09-03

    The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

  18. FACE RECOGNITION USING TWO DIMENSIONAL LAPLACIAN EIGENMAP

    Institute of Scientific and Technical Information of China (English)

    Chen Jiangfeng; Yuan Baozong; Pei Bingnan

    2008-01-01

    Recently,some research efforts have shown that face images possibly reside on a nonlinear sub-manifold. Though Laplacianfaces method considered the manifold structures of the face images,it has limits to solve face recognition problem. This paper proposes a new feature extraction method,Two Dimensional Laplacian EigenMap (2DLEM),which especially considers the manifold structures of the face images,and extracts the proper features from face image matrix directly by using a linear transformation. As opposed to Laplacianfaces,2DLEM extracts features directly from 2D images without a vectorization preprocessing. To test 2DLEM and evaluate its performance,a series of ex-periments are performed on the ORL database and the Yale database. Moreover,several experiments are performed to compare the performance of three 2D methods. The experiments show that 2DLEM achieves the best performance.

  19. Equivalency of two-dimensional algebras

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Gildemar Carneiro dos; Pomponet Filho, Balbino Jose S. [Universidade Federal da Bahia (UFBA), BA (Brazil). Inst. de Fisica

    2011-07-01

    Full text: Let us consider a vector z = xi + yj over the field of real numbers, whose basis (i,j) satisfy a given algebra. Any property of this algebra will be reflected in any function of z, so we can state that the knowledge of the properties of an algebra leads to more general conclusions than the knowledge of the properties of a function. However structural properties of an algebra do not change when this algebra suffers a linear transformation, though the structural constants defining this algebra do change. We say that two algebras are equivalent to each other whenever they are related by a linear transformation. In this case, we have found that some relations between the structural constants are sufficient to recognize whether or not an algebra is equivalent to another. In spite that the basis transform linearly, the structural constants change like a third order tensor, but some combinations of these tensors result in a linear transformation, allowing to write the entries of the transformation matrix as function of the structural constants. Eventually, a systematic way to find the transformation matrix between these equivalent algebras is obtained. In this sense, we have performed the thorough classification of associative commutative two-dimensional algebras, and find that even non-division algebra may be helpful in solving non-linear dynamic systems. The Mandelbrot set was used to have a pictorial view of each algebra, since equivalent algebras result in the same pattern. Presently we have succeeded in classifying some non-associative two-dimensional algebras, a task more difficult than for associative one. (author)

  20. Optical properties of two-dimensional (2D) CdSe nanostructures

    Science.gov (United States)

    Cherevkov, S. A.; Baranov, A. V.; Fedorov, A. V.; Litvin, A. P.; Artemyev, M. V.; Prudnikau, A. V.

    2013-09-01

    The resonant and off-resonant Raman spectra of optical phonons in two-dimensional CdSe nanocrystals of 5, 6, and 7 monolayers are analysed. The spectra are dominated by SO and LO phonon bands of CdSe, whose frequencies are thickness-independent in the off-resonant Raman scattering but demonstrate an evident thickness dependence in the case of the resonant Raman scattering.

  1. On numerical evaluation of two-dimensional phase integrals

    DEFF Research Database (Denmark)

    Lessow, H.; Rusch, W.; Schjær-Jacobsen, Hans

    1975-01-01

    The relative advantages of several common numerical integration algorithms used in computing two-dimensional phase integrals are evaluated.......The relative advantages of several common numerical integration algorithms used in computing two-dimensional phase integrals are evaluated....

  2. Tilted Two-Dimensional Array Multifocus Confocal Raman Microspectroscopy.

    Science.gov (United States)

    Yabumoto, Sohshi; Hamaguchi, Hiro-O

    2017-07-18

    A simple and efficient two-dimensional multifocus confocal Raman microspectroscopy featuring the tilted-array technique is demonstrated. Raman scattering from a 4 × 4 square foci array passing through a 4 × 4 confocal pinhole array is tilted with a periscope. The tilted array of Raman scattering signals is dispersed by an imaging spectrograph onto a CCD detector, giving 16 independent Raman spectra formed as 16 bands with different heights on the sensor. Use of a state-of-the-art imaging spectrograph enables high-precision wavenumber duplicability of the 16 spectra. This high duplicability makes the simultaneously obtained spectra endurable for multivariate spectral analyses, which is demonstrated by a singular value decomposition analysis for Raman spectra of liquid indene. Although the present implementation attains only 16 measurement points, the number of points can be extended to larger than 100 without any technical leaps. Limit of parallelization depends on the interval of measurement points as well as the performance of the optical system. Criteria for finding the maximum feasible number are discussed.

  3. Perspective: Two-dimensional resonance Raman spectroscopy

    Science.gov (United States)

    Molesky, Brian P.; Guo, Zhenkun; Cheshire, Thomas P.; Moran, Andrew M.

    2016-11-01

    Two-dimensional resonance Raman (2DRR) spectroscopy has been developed for studies of photochemical reaction mechanisms and structural heterogeneity in complex systems. The 2DRR method can leverage electronic resonance enhancement to selectively probe chromophores embedded in complex environments (e.g., a cofactor in a protein). In addition, correlations between the two dimensions of the 2DRR spectrum reveal information that is not available in traditional Raman techniques. For example, distributions of reactant and product geometries can be correlated in systems that undergo chemical reactions on the femtosecond time scale. Structural heterogeneity in an ensemble may also be reflected in the 2D spectroscopic line shapes of both reactive and non-reactive systems. In this perspective article, these capabilities of 2DRR spectroscopy are discussed in the context of recent applications to the photodissociation reactions of triiodide and myoglobin. We also address key differences between the signal generation mechanisms for 2DRR and off-resonant 2D Raman spectroscopies. Most notably, it has been shown that these two techniques are subject to a tradeoff between sensitivity to anharmonicity and susceptibility to artifacts. Overall, recent experimental developments and applications of the 2DRR method suggest great potential for the future of the technique.

  4. Janus spectra in two-dimensional flows

    CERN Document Server

    Liu, Chien-Chia; Chakraborty, Pinaki

    2016-01-01

    In theory, large-scale atmospheric flows, soap-film flows and other two-dimensional flows may host two distinct types of turbulent energy spectra---in one, $\\alpha$, the spectral exponent of velocity fluctuations, equals $3$ and the fluctuations are dissipated at the small scales, and in the other, $\\alpha=5/3$ and the fluctuations are dissipated at the large scales---but measurements downstream of obstacles have invariably revealed $\\alpha = 3$. Here we report experiments on soap-film flows where downstream of obstacles there exists a sizable interval in which $\\alpha$ has transitioned from $3$ to $5/3$ for the streamwise fluctuations but remains equal to $3$ for the transverse fluctuations, as if two mutually independent turbulent fields of disparate dynamics were concurrently active within the flow. This species of turbulent energy spectra, which we term the Janus spectra, has never been observed or predicted theoretically. Our results may open up new vistas in the study of turbulence and geophysical flows...

  5. Comparative Two-Dimensional Fluorescence Gel Electrophoresis.

    Science.gov (United States)

    Ackermann, Doreen; König, Simone

    2018-01-01

    Two-dimensional comparative fluorescence gel electrophoresis (CoFGE) uses an internal standard to increase the reproducibility of coordinate assignment for protein spots visualized on 2D polyacrylamide gels. This is particularly important for samples, which need to be compared without the availability of replicates and thus cannot be studied using differential gel electrophoresis (DIGE). CoFGE corrects for gel-to-gel variability by co-running with the sample proteome a standardized marker grid of 80-100 nodes, which is formed by a set of purified proteins. Differentiation of reference and analyte is possible by the use of two fluorescent dyes. Variations in the y-dimension (molecular weight) are corrected by the marker grid. For the optional control of the x-dimension (pI), azo dyes can be used. Experiments are possible in both vertical and horizontal (h) electrophoresis devices, but hCoFGE is much easier to perform. For data analysis, commercial software capable of warping can be adapted.

  6. Two-dimensional hexagonal semiconductors beyond graphene

    Science.gov (United States)

    Nguyen, Bich Ha; Hieu Nguyen, Van

    2016-12-01

    The rapid and successful development of the research on graphene and graphene-based nanostructures has been substantially enlarged to include many other two-dimensional hexagonal semiconductors (THS): phosphorene, silicene, germanene, hexagonal boron nitride (h-BN) and transition metal dichalcogenides (TMDCs) such as MoS2, MoSe2, WS2, WSe2 as well as the van der Waals heterostructures of various THSs (including graphene). The present article is a review of recent works on THSs beyond graphene and van der Waals heterostructures composed of different pairs of all THSs. One among the priorities of new THSs compared to graphene is the presence of a non-vanishing energy bandgap which opened up the ability to fabricate a large number of electronic, optoelectronic and photonic devices on the basis of these new materials and their van der Waals heterostructures. Moreover, a significant progress in the research on TMDCs was the discovery of valley degree of freedom. The results of research on valley degree of freedom and the development of a new technology based on valley degree of freedom-valleytronics are also presented. Thus the scientific contents of the basic research and practical applications os THSs are very rich and extremely promising.

  7. Two-Dimensional Phononic Crystals: Disorder Matters.

    Science.gov (United States)

    Wagner, Markus R; Graczykowski, Bartlomiej; Reparaz, Juan Sebastian; El Sachat, Alexandros; Sledzinska, Marianna; Alzina, Francesc; Sotomayor Torres, Clivia M

    2016-09-14

    The design and fabrication of phononic crystals (PnCs) hold the key to control the propagation of heat and sound at the nanoscale. However, there is a lack of experimental studies addressing the impact of order/disorder on the phononic properties of PnCs. Here, we present a comparative investigation of the influence of disorder on the hypersonic and thermal properties of two-dimensional PnCs. PnCs of ordered and disordered lattices are fabricated of circular holes with equal filling fractions in free-standing Si membranes. Ultrafast pump and probe spectroscopy (asynchronous optical sampling) and Raman thermometry based on a novel two-laser approach are used to study the phononic properties in the gigahertz (GHz) and terahertz (THz) regime, respectively. Finite element method simulations of the phonon dispersion relation and three-dimensional displacement fields furthermore enable the unique identification of the different hypersonic vibrations. The increase of surface roughness and the introduction of short-range disorder are shown to modify the phonon dispersion and phonon coherence in the hypersonic (GHz) range without affecting the room-temperature thermal conductivity. On the basis of these findings, we suggest a criteria for predicting phonon coherence as a function of roughness and disorder.

  8. Two-dimensional topological photonic systems

    Science.gov (United States)

    Sun, Xiao-Chen; He, Cheng; Liu, Xiao-Ping; Lu, Ming-Hui; Zhu, Shi-Ning; Chen, Yan-Feng

    2017-09-01

    The topological phase of matter, originally proposed and first demonstrated in fermionic electronic systems, has drawn considerable research attention in the past decades due to its robust transport of edge states and its potential with respect to future quantum information, communication, and computation. Recently, searching for such a unique material phase in bosonic systems has become a hot research topic worldwide. So far, many bosonic topological models and methods for realizing them have been discovered in photonic systems, acoustic systems, mechanical systems, etc. These discoveries have certainly yielded vast opportunities in designing material phases and related properties in the topological domain. In this review, we first focus on some of the representative photonic topological models and employ the underlying Dirac model to analyze the edge states and geometric phase. On the basis of these models, three common types of two-dimensional topological photonic systems are discussed: 1) photonic quantum Hall effect with broken time-reversal symmetry; 2) photonic topological insulator and the associated pseudo-time-reversal symmetry-protected mechanism; 3) time/space periodically modulated photonic Floquet topological insulator. Finally, we provide a summary and extension of this emerging field, including a brief introduction to the Weyl point in three-dimensional systems.

  9. Radiation effects on two-dimensional materials

    Energy Technology Data Exchange (ETDEWEB)

    Walker, R.C. II; Robinson, J.A. [Department of Materials Science, Penn State, University Park, PA (United States); Center for Two-Dimensional Layered Materials, Penn State, University Park, PA (United States); Shi, T. [Department of Mechanical and Nuclear Engineering, Penn State, University Park, PA (United States); Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI (United States); Silva, E.C. [GlobalFoundries, Malta, NY (United States); Jovanovic, I. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI (United States)

    2016-12-15

    The effects of electromagnetic and particle irradiation on two-dimensional materials (2DMs) are discussed in this review. Radiation creates defects that impact the structure and electronic performance of materials. Determining the impact of these defects is important for developing 2DM-based devices for use in high-radiation environments, such as space or nuclear reactors. As such, most experimental studies have been focused on determining total ionizing dose damage to 2DMs and devices. Total dose experiments using X-rays, gamma rays, electrons, protons, and heavy ions are summarized in this review. We briefly discuss the possibility of investigating single event effects in 2DMs based on initial ion beam irradiation experiments and the development of 2DM-based integrated circuits. Additionally, beneficial uses of irradiation such as ion implantation to dope materials or electron-beam and helium-beam etching to shape materials have begun to be used on 2DMs and are reviewed as well. For non-ionizing radiation, such as low-energy photons, we review the literature on 2DM-based photo-detection from terahertz to UV. The majority of photo-detecting devices operate in the visible and UV range, and for this reason they are the focus of this review. However, we review the progress in developing 2DMs for detecting infrared and terahertz radiation. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Photodetectors based on two dimensional materials

    Science.gov (United States)

    Zheng, Lou; Zhongzhu, Liang; Guozhen, Shen

    2016-09-01

    Two-dimensional (2D) materials with unique properties have received a great deal of attention in recent years. This family of materials has rapidly established themselves as intriguing building blocks for versatile nanoelectronic devices that offer promising potential for use in next generation optoelectronics, such as photodetectors. Furthermore, their optoelectronic performance can be adjusted by varying the number of layers. They have demonstrated excellent light absorption, enabling ultrafast and ultrasensitive detection of light in photodetectors, especially in their single-layer structure. Moreover, due to their atomic thickness, outstanding mechanical flexibility, and large breaking strength, these materials have been of great interest for use in flexible devices and strain engineering. Toward that end, several kinds of photodetectors based on 2D materials have been reported. Here, we present a review of the state-of-the-art in photodetectors based on graphene and other 2D materials, such as the graphene, transition metal dichalcogenides, and so on. Project supported by the National Natural Science Foundation of China (Nos. 61377033, 61574132, 61504136) and the State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences.

  11. Asymptotics for Two-dimensional Atoms

    DEFF Research Database (Denmark)

    Nam, Phan Thanh; Portmann, Fabian; Solovej, Jan Philip

    2012-01-01

    We prove that the ground state energy of an atom confined to two dimensions with an infinitely heavy nucleus of charge $Z>0$ and $N$ quantum electrons of charge -1 is $E(N,Z)=-{1/2}Z^2\\ln Z+(E^{\\TF}(\\lambda)+{1/2}c^{\\rm H})Z^2+o(Z^2)$ when $Z\\to \\infty$ and $N/Z\\to \\lambda$, where $E^{\\TF}(\\lambd......We prove that the ground state energy of an atom confined to two dimensions with an infinitely heavy nucleus of charge $Z>0$ and $N$ quantum electrons of charge -1 is $E(N,Z)=-{1/2}Z^2\\ln Z+(E^{\\TF}(\\lambda)+{1/2}c^{\\rm H})Z^2+o(Z^2)$ when $Z\\to \\infty$ and $N/Z\\to \\lambda$, where $E......^{\\TF}(\\lambda)$ is given by a Thomas-Fermi type variational problem and $c^{\\rm H}\\approx -2.2339$ is an explicit constant. We also show that the radius of a two-dimensional neutral atom is unbounded when $Z\\to \\infty$, which is contrary to the expected behavior of three-dimensional atoms....

  12. Predicting Two-Dimensional Silicon Carbide Monolayers.

    Science.gov (United States)

    Shi, Zhiming; Zhang, Zhuhua; Kutana, Alex; Yakobson, Boris I

    2015-10-27

    Intrinsic semimetallicity of graphene and silicene largely limits their applications in functional devices. Mixing carbon and silicon atoms to form two-dimensional (2D) silicon carbide (SixC1-x) sheets is promising to overcome this issue. Using first-principles calculations combined with the cluster expansion method, we perform a comprehensive study on the thermodynamic stability and electronic properties of 2D SixC1-x monolayers with 0 ≤ x ≤ 1. Upon varying the silicon concentration, the 2D SixC1-x presents two distinct structural phases, a homogeneous phase with well dispersed Si (or C) atoms and an in-plane hybrid phase rich in SiC domains. While the in-plane hybrid structure shows uniform semiconducting properties with widely tunable band gap from 0 to 2.87 eV due to quantum confinement effect imposed by the SiC domains, the homogeneous structures can be semiconducting or remain semimetallic depending on a superlattice vector which dictates whether the sublattice symmetry is topologically broken. Moreover, we reveal a universal rule for describing the electronic properties of the homogeneous SixC1-x structures. These findings suggest that the 2D SixC1-x monolayers may present a new "family" of 2D materials, with a rich variety of properties for applications in electronics and optoelectronics.

  13. Quantum magnetotransport in a modulated two-dimensional electron gas

    Science.gov (United States)

    Park, Tae-ik; Gumbs, Godfrey

    1997-09-01

    Quantum mechanical calculations of the magnetotransport coefficients of a modulated two-dimensional electron gas in a perpendicular magnetic field are presented using the Kubo method. The model modulation potential used is such that the effect of the steepness of the potential and its strength on the band part of the longitudinal resistivity ρxxand the Hall resistivity ρxycould be studied. In the extreme limit of a very steep potential, a two-dimensional square array of antidots is simulated. Impurity scattering is included in the self-consistent t-matrix approximation. The results show that for a strong lateral superlattice potential, ρxyis quenched in the low magnetic field regime and as the magnetic field increases there is a large negative Hall resistivity. The intensity of this negative peak is suppressed as the strength of the modulation potential is decreased. It is also shown that the height of the negative peak depends on the steepness of the potential. The longitudinal resistivity also has some interesting features. There are Aharonov-Bohm oscillations and a double peak structure which depends on both the strength of the modulation potential as well as its slope. The numerical results show that the position and intensity of the lower peak is not very sensitive to a change in the strength of the lattice potential or its steepness. However, the upper peak is greatly reduced when the lattice potential is diminished in strength. The double peak feature in ρxxand the negative peak and quenching of the Hall effect at low magnetic fields have been observed experimentally for antidots in both the quasiclassical and quantum regimes.

  14. Defect Characterization Using Two-Dimensional Arrays

    Science.gov (United States)

    Velichko, A.; Wilcox, P. D.

    2011-06-01

    2D arrays are able to `view' a given defect from a range of angles leading to the possibility of obtaining richer characterization detail than possible with 1D arrays. In this paper a quantitative comparison of 2D arrays with different element layouts is performed. A technique for extracting the scattering matrix of a defect from the raw 2D array data is also presented. The method is tested on experimental data for characterization of various volumetric defects.

  15. Bipartite entanglement entropy in massive two-dimensional quantum field theory.

    Science.gov (United States)

    Doyon, Benjamin

    2009-01-23

    Recently, Cardy, Castro Alvaredo, and the author obtained the first exponential correction to saturation of the bipartite entanglement entropy at large region lengths in massive two-dimensional integrable quantum field theory. It depends only on the particle content of the model, and not on the way particles scatter. Based on general analyticity arguments for form factors, we propose that this result is universal, and holds for any massive two-dimensional model (also out of integrability). We suggest a link of this result with counting pair creations far in the past.

  16. From spin flip excitations to the spin susceptibility enhancement of a two-dimensional electron gas.

    Science.gov (United States)

    Perez, F; Aku-leh, C; Richards, D; Jusserand, B; Smith, L C; Wolverson, D; Karczewski, G

    2007-07-13

    The g-factor enhancement of the spin-polarized two-dimensional electron gas was measured directly over a wide range of spin polarizations, using spin flip resonant Raman scattering spectroscopy on two-dimensional electron gases embedded in Cd(1-x)Mn(x)Te semimagnetic quantum wells. At zero Raman transferred momentum, the single-particle spin flip excitation, energy Z*, coexists in the Raman spectrum with the spin flip wave of energy Z, the bare giant Zeeman splitting. We compare the measured g-factor enhancement with recent spin-susceptibility enhancement theories and deduce the spin-polarization dependence of the mass renormalization.

  17. Interaction of two-dimensional magnetoexcitons

    Science.gov (United States)

    Dumanov, E. V.; Podlesny, I. V.; Moskalenko, S. A.; Liberman, M. A.

    2017-04-01

    We study interaction of the two-dimensional magnetoexcitons with in-plane wave vector k→∥ = 0 , taking into account the influence of the excited Landau levels (ELLs) and of the external electric field perpendicular to the surface of the quantum well and parallel to the external magnetic field. It is shown that the account of the ELLs gives rise to the repulsion between the spinless magnetoexcitons with k→∥ = 0 in the Fock approximation, with the interaction constant g decreasing inverse proportional to the magnetic field strength B (g (0) ∼ 1 / B) . In the presence of the perpendicular electric field the Rashba spin-orbit coupling (RSOC), Zeeman splitting (ZS) and nonparabolicity of the heavy-hole dispersion law affect the Landau quantization of the electrons and holes. They move along the new cyclotron orbits, change their Coulomb interactions and cause the interaction between 2D magnetoexcitons with k→∥ = 0 . The changes of the Coulomb interactions caused by the electrons and by the holes moving with new cyclotron orbits are characterized by some coefficients, which in the absence of the electric field turn to be unity. The differences between these coefficients of the electron-hole pairs forming the magnetoexcitons determine their affinities to the interactions. The interactions between the homogeneous, semihomogeneous and heterogeneous magnetoexcitons forming the symmetric states with the same signs of their affinities are attractive whereas in the case of different sign affinities are repulsive. In the heterogeneous asymmetric states the interactions have opposite signs in comparison with the symmetric states. In all these cases the interaction constant g have the dependence g (0) 1 /√{ B} .

  18. Two-dimensional materials and their prospects in transistor electronics.

    Science.gov (United States)

    Schwierz, F; Pezoldt, J; Granzner, R

    2015-05-14

    During the past decade, two-dimensional materials have attracted incredible interest from the electronic device community. The first two-dimensional material studied in detail was graphene and, since 2007, it has intensively been explored as a material for electronic devices, in particular, transistors. While graphene transistors are still on the agenda, researchers have extended their work to two-dimensional materials beyond graphene and the number of two-dimensional materials under examination has literally exploded recently. Meanwhile several hundreds of different two-dimensional materials are known, a substantial part of them is considered useful for transistors, and experimental transistors with channels of different two-dimensional materials have been demonstrated. In spite of the rapid progress in the field, the prospects of two-dimensional transistors still remain vague and optimistic opinions face rather reserved assessments. The intention of the present paper is to shed more light on the merits and drawbacks of two-dimensional materials for transistor electronics and to add a few more facets to the ongoing discussion on the prospects of two-dimensional transistors. To this end, we compose a wish list of properties for a good transistor channel material and examine to what extent the two-dimensional materials fulfill the criteria of the list. The state-of-the-art two-dimensional transistors are reviewed and a balanced view of both the pros and cons of these devices is provided.

  19. A compact multichannel spectrometer for Thomson scatteringa)

    Science.gov (United States)

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R.

    2012-10-01

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of Te VPH grating and measurements Te > 100 eV by a 2072 l/mm VPH grating. The spectrometer uses a fast-gated (˜2 ns) ICCD camera for detection. A Gen III image intensifier provides ˜45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  20. Exact two-body solutions and quantum defect theory of two-dimensional dipolar quantum gas

    Science.gov (United States)

    Jie, Jianwen; Qi, Ran

    2016-10-01

    In this paper, we provide the two-body exact solutions of the two-dimensional (2D) Schrödinger equation with isotropic +/- 1/{r}3 interactions. An analytic quantum defect theory is constructed based on these solutions and it is applied to investigate the scattering properties as well as two-body bound states of an ultracold polar molecules confined in a quasi-2D geometry. Interestingly, we find that for the attractive case, the scattering resonance happens simultaneously in all partial waves, which has not been observed in other systems. The effect of this feature on the scattering phase shift across such resonances is also illustrated.

  1. Ultrafast two dimensional infrared chemical exchange spectroscopy

    Science.gov (United States)

    Fayer, Michael

    2011-03-01

    The method of ultrafast two dimensional infrared (2D IR) vibrational echo spectroscopy is described. Three ultrashort IR pulses tuned to the frequencies of the vibrational transitions of interest are directed into the sample. The interaction of these pulses with the molecular vibrational oscillators produces a polarization that gives rise to a fourth pulse, the vibrational echo. The vibrational echo pulse is combined with another pulse, the local oscillator, for heterodyne detection of the signal. For fixed time between the second and third pulses, the waiting time, the first pulse is scanned. Two Fourier transforms of the data yield a 2D IR spectrum. The waiting time is increased, and another spectrum is obtained. The change in the 2D IR spectra with increased waiting time provides information on the time evolution of the structure of the molecular system under observation. In a 2D IR chemical exchange experiment, two species A and B, are undergoing chemical exchange. A's are turning into B's, and B's are turning into A's, but the overall concentrations of the species are not changing. The kinetics of the chemical exchange on the ground electronic state under thermal equilibrium conditions can be obtained 2D IR spectroscopy. A vibration that has a different frequency for the two species is monitored. At very short time, there will be two peaks on the diagonal of the 2D IR spectrum, one for A and one for B. As the waiting time is increased, chemical exchange causes off-diagonal peaks to grow in. The time dependence of the growth of these off-diagonal peaks gives the chemical exchange rate. The method is applied to organic solute-solvent complex formation, orientational isomerization about a carbon-carbon single bond, migration of a hydrogen bond from one position on a molecule to another, protein structural substate interconversion, and water hydrogen bond switching between ions and water molecules. This work was supported by the Air Force Office of Scientific

  2. Molecular assembly on two-dimensional materials

    Science.gov (United States)

    Kumar, Avijit; Banerjee, Kaustuv; Liljeroth, Peter

    2017-02-01

    Molecular self-assembly is a well-known technique to create highly functional nanostructures on surfaces. Self-assembly on two-dimensional (2D) materials is a developing field driven by the interest in functionalization of 2D materials in order to tune their electronic properties. This has resulted in the discovery of several rich and interesting phenomena. Here, we review this progress with an emphasis on the electronic properties of the adsorbates and the substrate in well-defined systems, as unveiled by scanning tunneling microscopy. The review covers three aspects of the self-assembly. The first one focuses on non-covalent self-assembly dealing with site-selectivity due to inherent moiré pattern present on 2D materials grown on substrates. We also see that modification of intermolecular interactions and molecule–substrate interactions influences the assembly drastically and that 2D materials can also be used as a platform to carry out covalent and metal-coordinated assembly. The second part deals with the electronic properties of molecules adsorbed on 2D materials. By virtue of being inert and possessing low density of states near the Fermi level, 2D materials decouple molecules electronically from the underlying metal substrate and allow high-resolution spectroscopy and imaging of molecular orbitals. The moiré pattern on the 2D materials causes site-selective gating and charging of molecules in some cases. The last section covers the effects of self-assembled, acceptor and donor type, organic molecules on the electronic properties of graphene as revealed by spectroscopy and electrical transport measurements. Non-covalent functionalization of 2D materials has already been applied for their application as catalysts and sensors. With the current surge of activity on building van der Waals heterostructures from atomically thin crystals, molecular self-assembly has the potential to add an extra level of flexibility and functionality for applications ranging

  3. Rothmund-Thomson syndrome

    Directory of Open Access Journals (Sweden)

    Roversi Gaia

    2010-01-01

    Full Text Available Abstract Rothmund-Thomson syndrome (RTS is a genodermatosis presenting with a characteristic facial rash (poikiloderma associated with short stature, sparse scalp hair, sparse or absent eyelashes and/or eyebrows, juvenile cataracts, skeletal abnormalities, radial ray defects, premature aging and a predisposition to cancer. The prevalence is unknown but around 300 cases have been reported in the literature so far. The diagnostic hallmark is facial erythema, which spreads to the extremities but spares the trunk, and which manifests itself within the first year and then develops into poikiloderma. Two clinical subforms of RTS have been defined: RTSI characterised by poikiloderma, ectodermal dysplasia and juvenile cataracts, and RTSII characterised by poikiloderma, congenital bone defects and an increased risk of osteosarcoma in childhood and skin cancer later in life. The skeletal abnormalities may be overt (frontal bossing, saddle nose and congenital radial ray defects, and/or subtle (visible only by radiographic analysis. Gastrointestinal, respiratory and haematological signs have been reported in a few patients. RTS is transmitted in an autosomal recessive manner and is genetically heterogeneous: RTSII is caused by homozygous or compound heterozygous mutations in the RECQL4 helicase gene (detected in 60-65% of RTS patients, whereas the aetiology in RTSI remains unknown. Diagnosis is based on clinical findings (primarily on the age of onset, spreading and appearance of the poikiloderma and molecular analysis for RECQL4 mutations. Missense mutations are rare, while frameshift, nonsense mutations and splice-site mutations prevail. A fully informative test requires transcript analysis not to overlook intronic deletions causing missplicing. The diagnosis of RTS should be considered in all patients with osteosarcoma, particularly if associated with skin changes. The differential diagnosis should include other causes of childhood poikiloderma

  4. The convolution theorem for two-dimensional continuous wavelet transform

    Institute of Scientific and Technical Information of China (English)

    ZHANG CHI

    2013-01-01

    In this paper , application of two -dimensional continuous wavelet transform to image processes is studied. We first show that the convolution and correlation of two continuous wavelets satisfy the required admissibility and regularity conditions ,and then we derive the convolution and correlation theorem for two-dimensional continuous wavelet transform. Finally, we present numerical example showing the usefulness of applying the convolution theorem for two -dimensional continuous wavelet transform to perform image restoration in the presence of additive noise.

  5. Interactions between lasers and two-dimensional transition metal dichalcogenides.

    Science.gov (United States)

    Lu, Junpeng; Liu, Hongwei; Tok, Eng Soon; Sow, Chorng-Haur

    2016-05-03

    The recent increasing research interest in two-dimensional (2D) layered materials has led to an explosion of in the discovery of novel physical and chemical phenomena in these materials. Among the 2D family, group-VI transition metal dichalcogenides (TMDs), such as represented by MoS2 and WSe2, are remarkable semiconductors with sizable energy band gaps, which make the TMDs promising building blocks for new generation optoelectronics. On the other hand, the specificity and tunability of the band gaps can generate particularly strong light-matter interactions between TMD crystals and specific photons, which can trigger complex and interesting phenomena such as photo-scattering, photo-excitation, photo-destruction, photo-physical modification, photochemical reaction and photo-oxidation. Herein, we provide an overview of the phenomena explained by various interactions between lasers and the 2D TMDs. Characterizations of the optical fundamentals of the TMDs via laser spectroscopies are reviewed. Subsequently, photoelectric conversion devices enabled by laser excitation and the functionality extension and performance improvement of the TMDs materials via laser modification are comprehensively summarized. Finally, we conclude the review by discussing the prospects for further development in this research area.

  6. Two-dimensional position sensitive ionization chamber with GEM

    Science.gov (United States)

    Kitamura, Noritaka; Noro, Tetsuo; Sakaguchi, Satoshi; Takao, Hideaki; Nishio, Yasutaka

    2014-09-01

    We have been developing a multi-anode ionization chamber for Accelerator Mass Spectrometry (AMS) at Kyushu University. Furthermore, we are planning to construct a neutron detector with high position resolution by combining the chamber with Gas Electron Multiplier (GEM) and a neutron converter. One of purposes is the measurement of p-> , pn knockout reaction from unstable nuclei. The multi-anode ionization chamber is composed of subdivided multiple anodes, a cathode to produce an uniform electric field, and a Frisch grid. The chamber must have position sensitivity because obtaining a beam profile is required for AMS measurements, where counting loss should be avoided. Also in the case of the neutron detector, it is necessary to measure the position to deduce the scattering angles. We have recently established a two-dimensional position readout system by the following methods: the measurement of horizontal position is enabled by trimming some anodes into wedge-like shape, and vertical position can be determined by the ratio of induced charge on the grid to the total charge on anodes. In addition, improvement of S/N ratio is important for isotope separation and position resolution. We installed a rectangular-shaped GEM and tried improving S/N ratio by electron amplification.

  7. Two-dimensional magnetic ordering in a multilayer structure

    Indian Academy of Sciences (India)

    M K Mukhopadhyay; M K Sanyal

    2006-07-01

    The effect of confinement from one, two or from all three directions on magnetic ordering has remained an active field of research for almost 100 years. The role of dipolar interactions and anisotropy are important to obtain, the otherwise forbidden, ferromagnetic ordering at finite temperature for ions arranged in two-dimensional (2D) arrays (monolayers). We have demonstrated that conventional low-temperature magnetometry and polarized neutron scattering measurements can be performed to study short-range ferromagnetic ordering of in-plane spins in 2D systems using a multilayer stack of non-interacting monolayers of gadolinium ions formed by Langmuir–Blodgett (LB) technique. The spontaneous magnetization could not be detected in the heterogeneous magnetic phase observed here and the saturation value of the net magnetization was found to depend on the sample temperature and applied magnetic field. The net magnetization rises exponentially with lowering temperature and then reaches saturation following a ln( ) dependence. The ln( ) dependence of magnetization has been predicted from spin-wave theory of 2D in-plane spin system with ferromagnetic interaction. The experimental findings reported here could be explained by extending this theory to a temperature domain of < 1.

  8. Design and experimental study of a two-dimensional position sensitive X-ray detector

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A prototype of a two-dimensional position sensitive X-ray detector was designed and constructed for small angle X-ray scattering experiments at BSFR (Beijing Synchrotron Radiation Facility). The detector is based on MWPC with cathode strip readout, and has a sensitive area of 200 mmx200 mm. The spatial resolution (FWHM) of about 210 μm along the anode wire direction was obtained from the 55Fe X-ray test of the detector.

  9. Numerical analysis of the Gibbs-Thomson effect on trench-filling epitaxial growth of 4H-SiC

    Science.gov (United States)

    Mochizuki, Kazuhiro; Ji, Shiyang; Kosugi, Ryoji; Kojima, Kazutoshi; Yonezawa, Yoshiyuki; Okumura, Hajime

    2016-03-01

    A steady-state two-dimensional diffusion equation was numerically analyzed to examine the rate of homoepitaxial growth on a trenched 4H-SiC substrate. The radii of curvature at the top and bottom of the trenches were used to take the Gibbs-Thomson effect into account in the analysis based on the conventional boundary-layer model. When the trench pitch was less than or equal to 6.0 µm, the measured dependence of the growth rate on the trench pitch was found to be explained by the Gibbs-Thomson effect on the vapor-phase diffusion of growing species.

  10. Two dimensional estimates from ocean SAR images

    Directory of Open Access Journals (Sweden)

    J. M. Le Caillec

    1996-01-01

    Full Text Available Synthetic Aperture Radar (SAR images of the ocean yield a lot of information on the sea-state surface providing that the mapping process between the surface and the image is clearly defined. However it is well known that SAR images exhibit non-gaussian statistics and that the motion of the scatterers on the surface, while the image is being formed, may yield to nonlinearities. The detection and quantification of these nonlinearities are made possible by using Higher Order Spectra (HOS methods and more specifically, bispectrum estimation. The development of the latter method allowed us to find phase relations between different parts of the image and to recognise their level of coupling, i.e. if and how waves of different wavelengths interacted nonlinearly. This information is quite important as the usual models assume strong nonlinearities when the waves are propagating in the azimuthal direction (i.e. along the satellite track and almost no nonlinearities when propagating in the range direction. In this paper, the mapping of the ocean surface to the SAR image is reinterpreted and a specific model (i.e. a Second Order Volterra Model is introduced. The nonlinearities are thus explained as either produced by a nonlinear system or due to waves propagating into selected directions (azimuth or range and interacting during image formation. It is shown that quadratic nonlinearities occur for waves propagating near the range direction while for those travelling in the azimuthal direction the nonlinearities, when present, are mostly due to wave interactions but are almost completely removed by the filtering effect coming from the surface motion itself (azimuth cut-off. An inherent quadratic interaction filtering (azimuth high pass filter is also present. But some other effects, apparently nonlinear, are not detected with the methods described here, meaning that either the usual relation developed for the Ocean-to-SAR transform is somewhat incomplete

  11. The Chandrasekhar's Equation for Two-Dimensional Hypothetical White Dwarfs

    CERN Document Server

    De, Sanchari

    2014-01-01

    In this article we have extended the original work of Chandrasekhar on the structure of white dwarfs to the two-dimensional case. Although such two-dimensional stellar objects are hypothetical in nature, we strongly believe that the work presented in this article may be prescribed as Master of Science level class problem for the students in physics.

  12. Beginning Introductory Physics with Two-Dimensional Motion

    Science.gov (United States)

    Huggins, Elisha

    2009-01-01

    During the session on "Introductory College Physics Textbooks" at the 2007 Summer Meeting of the AAPT, there was a brief discussion about whether introductory physics should begin with one-dimensional motion or two-dimensional motion. Here we present the case that by starting with two-dimensional motion, we are able to introduce a considerable…

  13. Spatiotemporal surface solitons in two-dimensional photonic lattices.

    Science.gov (United States)

    Mihalache, Dumitru; Mazilu, Dumitru; Lederer, Falk; Kivshar, Yuri S

    2007-11-01

    We analyze spatiotemporal light localization in truncated two-dimensional photonic lattices and demonstrate the existence of two-dimensional surface light bullets localized in the lattice corners or the edges. We study the families of the spatiotemporal surface solitons and their properties such as bistability and compare them with the modes located deep inside the photonic lattice.

  14. Explorative data analysis of two-dimensional electrophoresis gels

    DEFF Research Database (Denmark)

    Schultz, J.; Gottlieb, D.M.; Petersen, Marianne Kjerstine;

    2004-01-01

    Methods for classification of two-dimensional (2-DE) electrophoresis gels based on multivariate data analysis are demonstrated. Two-dimensional gels of ten wheat varieties are analyzed and it is demonstrated how to classify the wheat varieties in two qualities and a method for initial screening...

  15. Mechanics of Apparent Horizon in Two Dimensional Dilaton Gravity

    CERN Document Server

    Cai, Rong-Gen

    2016-01-01

    In this article, we give a definition of apparent horizon in a two dimensional general dilaton gravity theory. With this definition, we construct the mechanics of the apparent horizon by introducing a quasi-local energy of the theory. Our discussion generalizes the apparent horizons mechanics in general spherically symmetric spactimes in four or higher dimensions to the two dimensional dilaton gravity case.

  16. Topological aspect of disclinations in two-dimensional crystals

    Institute of Scientific and Technical Information of China (English)

    Qi Wei-Kai; Zhu Tao; Chen Yong; Ren Ji-Rong

    2009-01-01

    By using topological current theory, this paper studies the inner topological structure of disclinations during the melting of two-dimensional systems. From two-dimensional elasticity theory, it finds that there are topological currents for topological defects in homogeneous equation. The evolution of disclinations is studied, and the branch conditions for generating, annihilating, crossing, splitting and merging of disclinations are given.

  17. The distinctions between the electrical conductivities under non-contact and contact current excitation in spin–split two-dimensional conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kopeliovich, A.I. [B. Verkin Institute for Low Temperature Physics & Engineering, NAS of Ukraine (Ukraine); Pyshkin, P.V., E-mail: pavel.pyshkin@gmail.com [Ikerbasque, Basque Foundation for Science 48011, Bilbao (Spain); Department of Theoretical Physics and History of Science, The Basque Country University (EHU/UPV), PO Box 644, 48080 Bilbao (Spain); Kalinenko, A.N.; Yanovsky, A.V. [B. Verkin Institute for Low Temperature Physics & Engineering, NAS of Ukraine (Ukraine)

    2016-02-15

    It is shown that the normal electron–electron scattering is a source of electrical resistance on non-contact current excitation in two-dimensional spin–split electron systems. In contrast to the contact current injection, non-contact current excitation causes spatially inhomogeneous polarization in a two-dimensional conductor leading to new resistivity mechanisms.

  18. Invariant Subspaces of the Two-Dimensional Nonlinear Evolution Equations

    Directory of Open Access Journals (Sweden)

    Chunrong Zhu

    2016-11-01

    Full Text Available In this paper, we develop the symmetry-related methods to study invariant subspaces of the two-dimensional nonlinear differential operators. The conditional Lie–Bäcklund symmetry and Lie point symmetry methods are used to construct invariant subspaces of two-dimensional differential operators. We first apply the multiple conditional Lie–Bäcklund symmetries to derive invariant subspaces of the two-dimensional operators. As an application, the invariant subspaces for a class of two-dimensional nonlinear quadratic operators are provided. Furthermore, the invariant subspace method in one-dimensional space combined with the Lie symmetry reduction method and the change of variables is used to obtain invariant subspaces of the two-dimensional nonlinear operators.

  19. Inverse Gibbs-Thomson effect

    Science.gov (United States)

    Gershanov, V. Yu.; Garmashov, S. I.

    2015-01-01

    We prove the existence of an effect inverse to the Gibbs-Thomson effect for mass transfer in systems consisting of a solid phase and the solution of the solid phase material in a certain solvent. The effect involves a change in the shape of the interface due to a variation of the equilibrium concentrations under it, which is induced by external conditions, and exists in the presence of a negative feedback for mass transfer associated with capillary effects.

  20. The Innovative Technique at Thomson

    Directory of Open Access Journals (Sweden)

    Raveesh Agarwal

    2010-01-01

    Full Text Available Problem statement: As we continue to ride out of the current economic recession, employee engagement has become a critical business issue for the organization. It is tough time for Thomson Press to enhance its position as leader in printing industry and stay ahead of competition. Key challenges include identifying the areas of improvement and engaging each and every employee of the organization at an individual level so that everyone benefits-the business, the environment and the workforce. Approach: In order to meet the challenges and to sustain its leadership in the market, Thomson has taken a new initiative “Vaarta-an Employee Engagement survey”. To ensure the objectivity of this process and maintain the confidentiality of the responses, Thomson appointed “hrcraft business consultancy”, an external agency which specializes in conducting such surveys for many reputed organizations. Results: The survey identified areas of strength and weakness of the organization to assess levels of employee engagement and set new priorities for its employees and customer services. It helps officers and managers to gain useful insights, on how their team members engage with their team and then to take specific actions to address areas of concern. Equally, senior leadership will get insights on application of policy of the organization to enhance their motivation and drive. Conclusion: The objective of writing this case is to gain insight into the human resource practices being adopted at Thomson Press. This case described a new initiative-“Vaarta”, which will facilitate the organization through engagement of its employees into a high performance workforce during recession period. This will make a significant contribution to improvements in levels of customer satisfaction and business growth. It will help individual officers and managers in identifying specific and positive action steps towards engaging their team and thereby, enhancing and sustaining