WorldWideScience

Sample records for superdense magnetized plasmas

  1. Estimation of Nuclei Cooling Time by Electrons in Superdense Nonequilibrium Plasma

    CERN Document Server

    Kostenko, B F

    2004-01-01

    Estimations of nuclei cooling time by electrons in superdense nonequilibrium plasma formed at cavitation bubble collapse in deuterated acetone have been carried out. The necessity of these computations was stipulated by using in the latest theoretical calculations of nuclear reaction rate in these processes one poorly grounded assumption that electron temperatures remain essentially lower than nuclei ones during thermonuclear synthesis time t_s. The estimations have shown that the initial electron temperatures at the moment of superdense plasma formation with \\rho =100 g/cm^3 turn out to be appreciably lower than the nuclear temperatures, while the nuclei cooling time is of the same order as t_s.

  2. Picosecond X-ray radiography of superdense high-temperature laser plasma

    Science.gov (United States)

    Andreev, A. A.; Bel'kov, S. A.; Platonov, K. Yu.; Romanov, V. V.; Rogozhnikov, G. S.

    2017-09-01

    The layout of an X-ray source for diagnostics of the compressed state of laser plasma is proposed, and its optimal parameters are calculated under the conditions required for nuclear fusion. Such a source operating in a pulsed regime is intended to be used for determining the spatial distribution of laser-plasma density with high temporal resolution by means of multiframe (pulses follow with a specified time interval) backlight imaging of the main target by X-ray pulses obtained by irradiation of a secondary target by picosecond laser pulses.

  3. Electron energy distributions through superdense matter by Monte-Carlo simulations

    Directory of Open Access Journals (Sweden)

    Okabayashi A.

    2013-11-01

    Full Text Available We have studied energy distribution of fast electrons passing through a highly compressed core plasma for fast ignition research in inertial confinement fusion. Recent PIC calculations indicate that the collective effect of electric and magnetic fields on the transport may be less significant than the binary collisions in the case of a high density fusion pellet. In order to understand the net effect of binary collisions in dense plasma, we calculate electron energy distributions at several viewing angles using an electromagnetic cascade Monte-Carlo simulation, EGS5, for estimation of the contribution of multi collisional process. Here, the construction of physical parameters in the code were taken from the calculation results given by 2 dimensional particle-in-cell simulations. In the result, the number of electrons detected on the laser axis within the range to 15 MeV significantly decreases for the superdense region (max: 1.6⋅1025[/cm3] compared with the low density plasma. The reduction on the electron number decreases with increase of observation angles gradually and finally the number almost coincides more than 40 degrees.

  4. Turbulent transport in magnetized plasmas

    CERN Document Server

    Horton, Wendell

    2012-01-01

    This book explains how magnetized plasmas self-organize in states of electromagnetic turbulence that transports particles and energy out of the core plasma faster than anticipated by the fusion scientists designing magnetic confinement systems in the 20th century. It describes theory, experiments and simulations in a unified and up-to-date presentation of the issues of achieving nuclear fusion power.

  5. The quark-cluster phase of superdense matter

    Directory of Open Access Journals (Sweden)

    Guo-Chen Yang

    1983-01-01

    Full Text Available A quark-cluster phase of superdense matter is suggested. The 3-quark cluster is defined by γ3 = 0andγ8 = 0 but it is not necessarily a color-singlet. The new phase would lead to a long distance order of spin in superdense matter.

  6. Wave turbulence in magnetized plasmas

    Directory of Open Access Journals (Sweden)

    S. Galtier

    2009-02-01

    Full Text Available The paper reviews the recent progress on wave turbulence for magnetized plasmas (MHD, Hall MHD and electron MHD in the incompressible and compressible cases. The emphasis is made on homogeneous and anisotropic turbulence which usually provides the best theoretical framework to investigate space and laboratory plasmas. The solar wind and the coronal heating problems are presented as two examples of application of anisotropic wave turbulence. The most important results of wave turbulence are reported and discussed in the context of natural and simulated magnetized plasmas. Important issues and possible spurious interpretations are also discussed.

  7. Superdense coding facilitated by hyper-entanglement and quantum networks

    Science.gov (United States)

    Smith, James F.

    2017-05-01

    A method of generating superdense coding based on quantum hyper-entanglement and facilitated by quantum networks is discussed. Superdense coding refers to the coding of more than one classical bit into each qubit. Quantum hyperentanglement refers to quantum entanglement in more than one degree of freedom, e.g. polarization, energy-time, and orbital angular momentum (OAM). The new superdense coding scheme permits 2L bits to be encoded into each qubit where L is the number of degrees of freedom used for quantum hyper-entanglement. The superdense coding procedure is based on a generalization of the Bell state for L degrees of freedom. Theory describing the structure, generation/transmission, and detection of the generalized Bell state is developed. Circuit models are provided describing the generation/transmission process and detection process. Detection processes are represented mathematically as projection operators. A mathematical proof that that the detection scheme permits the generalized Bell states to be distinguished with 100% probability is provided. Measures of effectiveness (MOEs) are derived for the superdense coding scheme based on open systems theory represented in terms of density operators. Noise and loss related to generation/transmission, detection and propagation are included. The MOEs include various probabilities, quantum Chernoff bound, a measure of the number of message photons that must be transmitted to successfully send and receive a message, SNR and the quantum Cramer Rao' lower bound. Quantum networks with quantum memory are used to increase the efficiency of the superdense coding scheme.

  8. Relativistic Superdense Star Models of Pseudo Spheroidal Space-Time

    Science.gov (United States)

    Tikekar, Ramesh; Jotania, Kanti

    The physically viable models of compact stars like SAX (J1808.4-3658) can be obtained using Vaidya-Tikekar ansatz prescribing spheroidal geometry for their interior space-time. We discuss here the suitability of an alternative ansatz in this context. The models of superdense star are proposed using a general three parameter family of solutions of relativistic field equations obtained adopting the alternative ansatz. The setup is shown to admit physically viable models of superdense stars and strange matter stars such as Her. X-1.

  9. Charged analogue of Vlasenko–Pronin superdense star with ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 4. Charged analogue of Vlasenko–Pronin superdense ... 31, 1017 (2000), some particular values of the cosmological term are taken to obtain well-behaved solutionsof the Einstein–Maxwell field equations. All the results given by Maurya and Gupta can be ...

  10. Magnetic stresses in ideal MHD plasmas

    DEFF Research Database (Denmark)

    Jensen, V.O.

    1995-01-01

    The concept of magnetic stresses in ideal MHD plasma theory is reviewed and revisited with the aim of demonstrating its advantages as a basis for calculating and understanding plasma equilibria. Expressions are derived for the various stresses that transmit forces in a magnetized plasma...... and it is shown that the resulting magnetic forces on a finite volume element can be obtained by integrating the magnetic stresses over the surface of the element. The concept is used to rederive and discuss the equilibrium conditions for axisymmetric toroidal plasmas, including the virial theorem...

  11. Plasma Processes: Sheath and plasma parameters in a magnetized ...

    Indian Academy of Sciences (India)

    The variation of electron temperature and plasma density in a magnetized 2 plasma is studied experimentally in presence of a grid placed at the middle of the system. Plasma leaks through the negatively biased grid from the source region into the diffused region. It is observed that the electron temperature increases with ...

  12. Tokamak plasma self-organization-synergetics of magnetic trap plasmas

    NARCIS (Netherlands)

    Razumova, K. A.; Andreev, V. F.; Eliseev, L. G.; Kislov, A. Y.; La Haye, R. J.; Lysenko, S. E.; Melnikov, A. V.; Notkin, G. E.; Pavlov, Y. D.; Kantor, M. Y.

    2011-01-01

    Analysis of a wide range of experimental results in plasma magnetic confinement investigations shows that in most cases, plasmas are self-organized. In the tokamak case, it is realized in the self-consistent pressure profile, which permits the tokamak plasma to be macroscopically MHD stable.

  13. Three Dimensional Double Layers in Magnetized Plasmas

    DEFF Research Database (Denmark)

    Jovanovic, D.; Lynov, Jens-Peter; Michelsen, Poul

    1982-01-01

    Experimental results are presented which demonstrate the formation of fully three dimensional double layers in a magnetized plasma. The measurements are performed in a magnetized stationary plasma column with radius 1.5 cm. Double layers are produced by introducing an electron beam with radius 0...

  14. Ionization equilibrium of a magnetized quantum plasma

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, M.; Ortner, J.; Ebeling, W. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik

    2001-07-01

    The influence of a constant uniform magnetic field on the ionization equilibrium and the thermodynamic properties of a nondegenerate partially ionized hydrogen plasma is studied for weak and strong magnetic fields. A simple interpolation formula for an effective partition function is proposed, connecting the the low- and high-field results. Furthermore, a closed analytical approximation for the thermodynamic functions in the chemical picture and a Saha equation for weakly and strongly magnetized plasmas are presented. (orig.)

  15. Efficient magnetic fields for supporting toroidal plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Landreman, Matt, E-mail: mattland@umd.edu [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Boozer, Allen H. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

    2016-03-15

    The magnetic field that supports tokamak and stellarator plasmas must be produced by coils well separated from the plasma. However, the larger the separation, the more difficult it is to produce a given magnetic field in the plasma region, so plasma configurations should be chosen that can be supported as efficiently as possible by distant coils. The efficiency of an externally generated magnetic field is a measure of the field's shaping component magnitude at the plasma compared to the magnitude near the coils; the efficiency of a plasma equilibrium can be measured using the efficiency of the required external shaping field. Counterintuitively, plasma shapes with low curvature and spectral width may have low efficiency, whereas plasma shapes with sharp edges may have high efficiency. Two precise measures of magnetic field efficiency, which correctly identify such differences in difficulty, will be examined. These measures, which can be expressed as matrices, relate the externally produced normal magnetic field on the plasma surface to the either the normal field or current on a distant control surface. A singular value decomposition (SVD) of either matrix yields an efficiency ordered basis for the magnetic field distributions. Calculations are carried out for both tokamak and stellarator cases. For axisymmetric surfaces with circular cross-section, the SVD is calculated analytically, and the range of poloidal and toroidal mode numbers that can be controlled to a given desired level is determined. If formulated properly, these efficiency measures are independent of the coordinates used to parameterize the surfaces.

  16. Magnetic filtered plasma deposition and implantation technique

    CERN Document Server

    Zhang Hui Xing; Wu Xian Ying

    2002-01-01

    A high dense metal plasma can be produced by using cathodic vacuum arc discharge technique. The microparticles emitted from the cathode in the metal plasma can be removed when the metal plasma passes through the magnetic filter. It is a new technique for making high quality, fine and close thin films which have very widespread applications. The authors describe the applications of cathodic vacuum arc technique, and then a filtered plasma deposition and ion implantation system as well as its applications

  17. Magnetic circuit for hall effect plasma accelerator

    Science.gov (United States)

    Manzella, David H. (Inventor); Jacobson, David T. (Inventor); Jankovsky, Robert S. (Inventor); Hofer, Richard (Inventor); Peterson, Peter (Inventor)

    2009-01-01

    A Hall effect plasma accelerator includes inner and outer electromagnets, circumferentially surrounding the inner electromagnet along a thruster centerline axis and separated therefrom, inner and outer magnetic conductors, in physical connection with their respective inner and outer electromagnets, with the inner magnetic conductor having a mostly circular shape and the outer magnetic conductor having a mostly annular shape, a discharge chamber, located between the inner and outer magnetic conductors, a magnetically conducting back plate, in magnetic contact with the inner and outer magnetic conductors, and a combined anode electrode/gaseous propellant distributor, located at a bottom portion of the discharge chamber. The inner and outer electromagnets, the inner and outer magnetic conductors and the magnetically conducting back plate form a magnetic circuit that produces a magnetic field that is largely axial and radially symmetric with respect to the thruster centerline.

  18. Ultracold plasma dynamics in a magnetic field

    Science.gov (United States)

    Zhang, Xianli

    Plasmas, often called the fourth state of matter and the most common one in the universe, have parameters varying by many orders of magnitude, from temperature of a few hundred kelvin in the Earth's ionosphere to 10 16 K in the magnetosphere of a pulsar. Ultracold plasmas, produced by photoionizing a sample of laser-cooled and trapped atoms near the ionization limit, have extended traditional neutral plasma parameters by many orders of magnitude, to electron temperatures below 1 K and ion temperatures in the tens of muK to a few Kelvin, and densities of 105 cm -3 to 1010 cm-3. These plasmas thus provide a testing ground to study basic plasma theory in a clean and simple system with or without a magnetic field. Previous studies of ultracold plasmas have primarily concentrated on temperature measurements, collective modes and expansion dynamics in the absence of magnetic fields. This thesis presents the first study of ultracold plasma dynamics in a magnetic field. The presence of a magnetic field during the expansion can initiate various phenomena, such as plasma confinement and plasma instabilities. While the electron temperatures are very low in ultracold plasmas, we need only tens of Gauss of magnetic field to observe significant effects on the expansion dynamics. To probe the ultraocold plasma dynamics in a magnetic field, we developed a new diagnostic - projection imaging, which images the ion distribution by extracting the ions with a high voltage pulse onto a position-sensitive detector. Early in the lifetime of the plasma (explosion of the dense ion cloud. For later times, we measure the 2-D Gaussian width of the ion image, obtaining the transverse expansion velocity as a function of magnetic field (up to 70 G), and observe that the transverse expansion velocity scales as B-1/2, explained by a nonlinear ambipolar diffusion model that involes anisotropic diffusion in two different directions. We also present the first observation of a plasma instability in an

  19. Nonlinear Electrostatic Wave Equations for Magnetized Plasmas

    DEFF Research Database (Denmark)

    Dysthe, K.B.; Mjølhus, E.; Pécseli, Hans

    1984-01-01

    The lowest order kinetic effects are included in the equations for nonlinear electrostatic electron waves in a magnetized plasma. The modifications of the authors' previous analysis based on a fluid model are discussed.......The lowest order kinetic effects are included in the equations for nonlinear electrostatic electron waves in a magnetized plasma. The modifications of the authors' previous analysis based on a fluid model are discussed....

  20. Experimental investigation of magnetically confined plasma loops

    Energy Technology Data Exchange (ETDEWEB)

    Tenfelde, Jan

    2012-12-11

    Arch-shaped magnetic flux tubes generated in a pulsed-power plasma experiment were investigated with a variety of diagnostics concerning their expansion properties. Specifically, the expansion velocity was of interest, which is observed as constant for a wide range of experimental parameters. An MHD transport mechanism is investigated as possible cause of a uniform arch cross section: Axial transport of poloidal magnetic flux along the plasma may cause a pinch force leading to a uniform diameter along the arch. Despite numerous experimental findings at a very similar experimental setup, no indication for the relevance of this process could be found. Instead, magnetic probe data showed that the plasma current in the apex region is constant. A constant expansion velocity was observed for considerably different experimental conditions. This included different plasma source designs with fundamentally different toroidal magnetic field topology and variation of the working gas, which lead to plasma densities lower by an order of magnitude. Inside the current channel of the arch, Alfven velocities were estimated. To this end, plasma density profiles obtained from interferometry were inverted to obtain local densities, which were in turn verified by means of Stark broadening of hydrogen Balmer lines. Furthermore, measurements of multiple components of the magnetic field of the plasma arch were performed. An estimate for the conductivity was obtained from Spitzer's formula for fully ionized plasma using electron temperatures obtained from elementary optical emission spectroscopy. From the presented data of ccd imaging, magnetic field probes, and to lesser extent, interferometry, the underlying assumption of residual plasma (and considerable plasma currents through it) below the actual arch structure is very plausible. Rough estimates of the electric field strength along the arch and results of the magnetic field measurements showed, that the detected expansion

  1. Magnetically stabilized plasma sources of getter films

    Energy Technology Data Exchange (ETDEWEB)

    Karpov, D.; Saksagansky, G. (Div. Efremov Scientific Research Inst. of Electrophysical Apparatus, Leningrad (USSR))

    1990-01-01

    Modern state and ways of development of getter film plasma sources with the magnetic stabilization (GFPS) are considered. The description of physical mechanism of the magnetic stabilization, GFPS constructions and technical characteristics, their confronting parameters and the main factors defining usage perspectives is presented. (orig.).

  2. Laser-Plasma Interactions in Magnetized Environment

    Science.gov (United States)

    Shi, Yuan

    2017-10-01

    Propagation and scattering of lasers present new phenomena and applications when the plasma medium becomes magnetized. Starting from mega-Gauss magnetic fields, laser scattering becomes manifestly anisotropic [arXiv 1705.09758]. By arranging beams at special angles, one may be able to optimize laser-plasma coupling in magnetized environment. In stronger giga-Gauss magnetic field, laser propagation becomes modified by relativistic quantum effects [PRA 94.012124]. The modified wave dispersion relation enables correct interpretation of Faraday rotation measurements of strong magnetic fields, as well as correct extraction of plasma parameters from the X-ray spectra of pulsars. In addition, magnetized plasmas can be utilized to mediate laser pulse compression [PRE 95.023211]. Using magnetic resonances, it is not only possible to produce optic pulses of higher intensity, but also possible to amplify UV and soft X-ray pulses that cannot be compressed using existing technology. This research is supported by NNSA Grant No. DE-NA0002948 and DOE Research Grant No. DEAC02- 09CH11466.

  3. Dynamics of exploding plasmas in a large magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, C.; Gekelman, W.; Constantin, C. G.; Everson, E. T.; Schaeffer, D. B.; Clark, S. E.; Zylstra, A. B.; Pribyl, P.; Tripathi, S. K. P.; Bondarenko, A. S. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States); Winske, D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Larson, D.; Glenzer, S. H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2013-01-15

    The dynamics of an exploding laser-produced plasma in a large ambient magneto-plasma was investigated with magnetic flux probes and Langmuir probes. Debris-ions expanding at super-Alfvenic velocity (up to M{sub A}=1.5) expel the ambient magnetic field, creating a large (>20 cm) diamagnetic cavity. We observe a field compression of up to B/B{sub 0}=1.5 as well as localized electron heating at the edge of the bubble. Two-dimensional hybrid simulations reproduce these measurements well and show that the majority of the ambient ions are energized by the magnetic piston and swept outside the bubble volume. Nonlinear shear-Alfven waves ({delta}B/B{sub 0}>25%) are radiated from the cavity with a coupling efficiency of 70% from magnetic energy in the bubble to the wave.

  4. Development of a Rotating Magnetized Plasma Device

    Science.gov (United States)

    Cooke, David; Patton, James; Reid, Remington; Stiles, Ashley; Morrison, Patrik; Koch, Andrei

    2017-10-01

    Momentum coupling in plasma is a mechanism that is central to a wide range of interesting and important phenomena, magnetosphere-ionosphere coupling, solar eruptions, the interaction of an electro-dynamic tether system in the Earth's ionosphere, and the Critical Ionization Velocity (CIV) mechanism are a few examples. One result of the Space Shuttle Tethered Satellite experiment, TSS-1R, was that the current-voltage response of the experiment in all orbit conditions fell into a narrow range of curves when parameterized as a plasma probe [Thompson, GRL,1998]. Another striking result was the lack of dependence on the Alfvén velocity or other electro-magnetic parameters. This result has led us to revisit the understanding of the speed with which an electric field propagates along the magnetic field using EM-PIC simulation and experiments in our new magnetized plasma chamber. Our initial experiment is a rotating plasma using a solenoidal magnetic field and a radial electric field, with pulsed differential rotation of the plasma column to study the strength of coupling and propagation speed. Characteristics of our `first light' rotating plasma will be presented. Supported by Air Force Office Scientific Research 16RVCOR264.

  5. Evidence of superdense aluminium synthesized by ultrafast microexplosion

    Energy Technology Data Exchange (ETDEWEB)

    Vailionis, Arturas; Gamaly, Eugene G.; Mizeikis, Vygantas; Yang, Wenge; Rode, Andrei V.; Juodkazis, Saulius (Swinburne); (Stanford); (CIW); (ANU); (Shinshu-MED)

    2011-09-20

    At extreme pressures and temperatures, such as those inside planets and stars, common materials form new dense phases with compacted atomic arrangements and unusual physical properties. The synthesis and study of new phases of matter at pressures above 100 GPa and temperatures above 10{sup 4} K - warm dense matter - may reveal the functional details of planet and star interiors, and may lead to materials with extraordinary properties. Many phases have been predicted theoretically that may be realized once appropriate formation conditions are found. Here we report the synthesis of a superdense stable phase of body-centred-cubic aluminium, predicted by first-principles theories to exist at pressures above 380 GPa. The superdense Al phase was synthesized in the non-equilibrium conditions of an ultrafast laser-induced microexplosion confined inside sapphire ({alpha}-Al{sub 2}O{sub 3}). Confined microexplosions offer a strategy to create and recover high-density polymorphs, and a simple method for tabletop study of warm dense matter.

  6. Heat flux viscosity in collisional magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C., E-mail: cliu@pppl.gov [Princeton University, Princeton, New Jersey 08544 (United States); Fox, W. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Bhattacharjee, A. [Princeton University, Princeton, New Jersey 08544 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2015-05-15

    Momentum transport in collisional magnetized plasmas due to gradients in the heat flux, a “heat flux viscosity,” is demonstrated. Even though no net particle flux is associated with a heat flux, in a plasma there can still be momentum transport owing to the velocity dependence of the Coulomb collision frequency, analogous to the thermal force. This heat-flux viscosity may play an important role in numerous plasma environments, in particular, in strongly driven high-energy-density plasma, where strong heat flux can dominate over ordinary plasma flows. The heat flux viscosity can influence the dynamics of the magnetic field in plasmas through the generalized Ohm's law and may therefore play an important role as a dissipation mechanism allowing magnetic field line reconnection. The heat flux viscosity is calculated directly using the finite-difference method of Epperlein and Haines [Phys. Fluids 29, 1029 (1986)], which is shown to be more accurate than Braginskii's method [S. I. Braginskii, Rev. Plasma Phys. 1, 205 (1965)], and confirmed with one-dimensional collisional particle-in-cell simulations. The resulting transport coefficients are tabulated for ease of application.

  7. Wiedemann-Franz law for magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hensler, E. [Innsbruck Univ. (Austria)

    1992-12-31

    The electrical and the thermal conductivities of a plasma are transport coefficients of major interest in magnetic confinement fusion research. In metals the ratio of the thermal conductivity, {kappa}, to the electrical conductivity, {sigma}, is proportional to the temperature, T, (Wiedemann-Franz law in the form given by Lorenz). In this paper we investigate the so-called Lorenz number L={kappa}/{sigma}T in the case of a two-fluid plasma in a uniform magnetic field, where we have to distinguish the various directional fluxes and the electron and ion contributions. The check of the validity of the Wiedemann-Franz law for a plasma has not received much attention in the literature except in some plasma physics textbooks, which have used simple collision terms. In the present paper we employ the full Fokker-Planck collision term. (author) 5 refs.

  8. Transient Growth in a Magnetized Vlasov Plasma

    Science.gov (United States)

    Ratushnaya, Valeria; Samtaney, Ravi

    2015-11-01

    Collisionless plasmas, such as those encountered in tokamaks, exhibit a rich variety of instabilities. The physical origin, triggering mechanisms and fundamental understanding of many tokamak instabilities, however, is still an open problem. Aiming to gain a better insight into this question, we investigate the stability properties of a collisionless Vlasov plasma for the case of: (a) stationary homogeneous magnetic field, and (b) weakly non-stationary and non-homogeneous magnetic field. We narrow the scope of our investigation to the case of a Maxwellian plasma and examine its evolution with an electrostatic approximation. We show that the linearized Vlasov operator is non-normal, which leads to an algebraic growth of perturbations in a magnetized plasma followed by exponential decay, i.e., classical Landau damping behaviour. This is a so-called transient growth phenomenon, developed in the framework of non-modal stability theory in the context of hydrodynamics. In a homogeneous magnetic field the typical time scales of the transient growth are of the order of several plasma periods. The first-order distribution function and the corresponding electric field are calculated and the dependence on the initial conditions is studied. Supported by baseline research funds at KAUST.

  9. Nonlinear Electron Waves in Strongly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens

    1980-01-01

    Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...... dynamics in the analysis is also demonstrated. As a particular case the authors investigate nonlinear waves in a strongly magnetized plasma filled wave-guide, where the effects of finite geometry are important. The relevance of this problem to laboratory experiments is discussed....

  10. Plasma Equilibria With Stochastic Magnetic Fields

    Science.gov (United States)

    Krommes, J. A.; Reiman, A. H.

    2009-05-01

    Plasma equilibria that include regions of stochastic magnetic fields are of interest in a variety of applications, including tokamaks with ergodic limiters and high-pressure stellarators. Such equilibria are examined theoretically, and a numerical algorithm for their construction is described.^2,3 % The balance between stochastic diffusion of magnetic lines and small effects^2 omitted from the simplest MHD description can support pressure and current profiles that need not be flattened in stochastic regions. The diffusion can be described analytically by renormalizing stochastic Langevin equations for pressure and parallel current j, with particular attention being paid to the satisfaction of the periodicity constraints in toroidal configurations with sheared magnetic fields. The equilibrium field configuration can then be constructed by coupling the prediction for j to Amp'ere's law, which is solved numerically. A. Reiman et al., Pressure-induced breaking of equilibrium flux surfaces in the W7AS stellarator, Nucl. Fusion 47, 572--8 (2007). J. A. Krommes and A. H. Reiman, Plasma equilibrium in a magnetic field with stochastic regions, submitted to Phys. Plasmas. J. A. Krommes, Fundamental statistical theories of plasma turbulence in magnetic fields, Phys. Reports 360, 1--351.

  11. Scaling laws in magnetized plasma turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Boldyrev, Stanislav [Univ. of Wisconsin, Madison, WI (United States)

    2015-06-28

    Interactions of plasma motion with magnetic fields occur in nature and in the laboratory in an impressively broad range of scales, from megaparsecs in astrophysical systems to centimeters in fusion devices. The fact that such an enormous array of phenomena can be effectively studied lies in the existence of fundamental scaling laws in plasma turbulence, which allow one to scale the results of analytic and numerical modeling to the sized of galaxies, velocities of supernovae explosions, or magnetic fields in fusion devices. Magnetohydrodynamics (MHD) provides the simplest framework for describing magnetic plasma turbulence. Recently, a number of new features of MHD turbulence have been discovered and an impressive array of thought-provoking phenomenological theories have been put forward. However, these theories have conflicting predictions, and the currently available numerical simulations are not able to resolve the contradictions. MHD turbulence exhibits a variety of regimes unusual in regular hydrodynamic turbulence. Depending on the strength of the guide magnetic field it can be dominated by weakly interacting Alfv\\'en waves or strongly interacting wave packets. At small scales such turbulence is locally anisotropic and imbalanced (cross-helical). In a stark contrast with hydrodynamic turbulence, which tends to ``forget'' global constrains and become uniform and isotropic at small scales, MHD turbulence becomes progressively more anisotropic and unbalanced at small scales. Magnetic field plays a fundamental role in turbulent dynamics. Even when such a field is not imposed by external sources, it is self-consistently generated by the magnetic dynamo action. This project aims at a comprehensive study of universal regimes of magnetic plasma turbulence, combining the modern analytic approaches with the state of the art numerical simulations. The proposed study focuses on the three topics: weak MHD turbulence, which is relevant for laboratory devices

  12. Langmuir Solitons in Magnetized Plasmas

    DEFF Research Database (Denmark)

    Dysthe, K. B.; Mjølhus, E.; Pécseli, Hans

    1978-01-01

    The authors have considered the nonlinear interaction between a high frequency (Langmuir) wave, which propagates at an arbitrary angle to a weak, constant magnetic field, and low frequency (ion-cyclotron or ion-sound) perturbations. In studying Langmuir envelope solitons they have unified...

  13. Wave spectra of strongly coupled magnetized plasmas

    Science.gov (United States)

    Kaehlert, Hanno; Reynolds, Alexi; Ott, Torben; Bonitz, Michael

    2011-10-01

    Results are presented for the wave propagation in a strongly coupled, magnetized one-component plasma. For different angles of the wave vector with respect to the external magnetic field we discuss the dispersion and polarization based on the quasi-localized charge approximation (QLCA). Further, the results of the QLCA are compared with molecular dynamics simulations, extending previous results for two-dimensional systems, e.g.,. The dependence of the wave spectra on the coupling parameter and the magnetic field strength is examined. Support by the Deutsche Forschungsgemeinschaft via SFB-TR 24 and DAAD via the RISE program is acknowledged.

  14. Dynamics of Magnetized Plasma Jets and Bubbles Launched into a Background Magnetized Plasma

    Science.gov (United States)

    Wallace, B.; Zhang, Y.; Fisher, D. M.; Gilmore, M.

    2016-10-01

    The propagation of dense magnetized plasma, either collimated with mainly azimuthal B-field (jet) or toroidal with closed B-field (bubble), in a background plasma occurs in a number of solar and astrophysical cases. Such cases include coronal mass ejections moving in the background solar wind and extragalactic radio lobes expanding into the extragalactic medium. Understanding the detailed MHD behavior is crucial for correctly modeling these events. In order to further the understanding of such systems, we are investigating the injection of dense magnetized jets and bubbles into a lower density background magnetized plasma using a coaxial plasma gun and a background helicon or cathode plasma. In both jet and bubble cases, the MHD dynamics are found to be very different when launched into background plasma or magnetic field, as compared to vacuum. In the jet case, it is found that the inherent kink instability is stabilized by velocity shear developed due to added magnetic tension from the background field. In the bubble case, rather than directly relaxing to a minimum energy Taylor state (spheromak) as in vacuum, there is an expansion asymmetry and the bubble becomes Rayleigh-Taylor unstable on one side. Recent results will be presented. Work supported by the Army Research Office Award No. W911NF1510480.

  15. Role of Magnetic Interaction in Dense Plasma

    Directory of Open Access Journals (Sweden)

    S. Sarkar

    2013-01-01

    Full Text Available Quasiparticle excitations and associated phenomena of energy and momentum transfer rates have been calculated in terms of the drag and the diffusion coefficients exposing clearly the dominance of the magnetic interaction over its electric counterpart. The results have been compared with the finite temperature results highlighting the similarities and dissimilarities in the two extreme regimes of temperature and density. Non-Fermi-liquid behavior of various physical quantities like neutrino mean free path and thermal relaxation time due to the inclusion of magnetic interaction has clearly been revealed. All the results presented in the current review are pertinent to the degenerate and ultradegenerate plasma.

  16. Molecular dynamics simulations of magnetized dusty plasmas

    Science.gov (United States)

    Piel, Alexander; Reichstein, Torben; Wilms, Jochen

    2012-10-01

    The combination of the electric field that confines a dust cloud with a static magnetic field generally leads to a rotation of the dust cloud. In weak magnetic fields, the Hall component of the ion flow exerts a drag force that sets the dust in rotation. We have performed detailed molecular-dynamics simulations of the dynamics of torus-shaped dust clouds in anodic plasmas. The stationary flow [1] is characterized by a shell structure in the laminar dust flow and by the spontaneous formation of a shear-flow around a stationary vortex. Here we present new results on dynamic phenomena, among them fluctuations due to a Kelvin-Helmholtz instability in the shear-flow. The simulations are compared with experimental results. [4pt] [1] T. Reichstein, A. Piel, Phys. Plasmas 18, 083705 (2011)

  17. Nonlinear magnetic reconnection in low collisionality plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ottaviani, M. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Porcelli, F. [Politecnico di Torino, Turin (Italy)

    1994-07-01

    The magnetic reconnection in collisionless regimes, where electron inertia is responsible for the decoupling of the plasma motion from that of the field lines, is discussed. Since the linear theory of m=1 modes breaks down for very small magnetic island widths, a non linear analysis is called for. Thus, the behaviour of a collisionless, 2-D fluid slab model in the limit {rho}/d -> 0, is analyzed. The main result is that, when the island size is larger than the linear layer but smaller than the equilibrium scale length, the reconnection rate exhibits a quasi-explosive time behaviour, during which a current density sub-layer narrower than the skin depth is formed. It is believed that the inclusion of the electron initial term in Ohm`s law opens the possibility to understand the rapidity of relaxation process observed in low collisionality plasmas. 7 refs., 6 figs.

  18. Simulating the injection of magnetized plasma without electromagnetic precursor wave

    Science.gov (United States)

    Kilian, Patrick; Spanier, Felix

    2018-01-01

    This note aims to explain how to inject magnetized plasma through an open boundary into the simulation domain of a particle-in-cell simulation. If the magnetic field at the boundary is constant in time, i.e., if magnetized plasma of constant magnetization is injected at a steady rate, this does not present any challenges beyond injecting the particles at a fixed rate and possibly absorbing plasma waves impinging on the wall. If, however, the magnetization or the injection rate changes, a time-varying magnetic field is present. The classical use case for this scenario is a shock front moving through a plasma into the simulation volume.

  19. Dispersion relations in cold magnetized plasmas

    OpenAIRE

    Cheverry, Christophe; Fontaine, Adrien

    2017-01-01

    International audience; Starting from kinetic models of cold magnetized collisionless plasmas, we provide a complete description of the characteristic variety sustaining electromagnetic wave propagation. Our analysis is based on some asymptotic calculus exploiting the presence at the level of dimensionless relativistic Vlasov-Maxwell equations of a large parameter: the electron gyrofrequency. Our method is inspired from geometric optics. It allows to unify preceding results, while incorporati...

  20. Plasma opening switch with extrinsic magnetic field

    CERN Document Server

    Dolgachev, G; Maslennikov, D

    2001-01-01

    Summary form only given, as follows. We have demonstrated in series of experiments that plasma opening switch (POS) switching voltage (UPOS) is defined by energy density (w) deposited in the POS plasma. If we then consider a plasma erosion mainly responsible for the effect of POS switching (the erosion effect could be described by Hall or Child-Langmuir models) the energy density (w) could be measured as a function of a system "macro-parameter" such as the initial charging voltage of the capacity storage system (the Marx pulsed voltage generator) UMarx. The POS voltage in this case could be given by UPOS"aw=aUMarx4/7, where a is a constant. This report demonstrates that for the high-impedance POS which has limited charge density transferred through the POS plasma a"2.5 (MV3/7) with no external magnetic field applied. The use of the extrinsic magnetic field allows to increase a up to 3.6 (MV3/7) and to achieve higher voltages at the opening phase - UPOS=3.6UMarx4/7. To verify this approach set of experimental ...

  1. Effect of magnetic reconnection in stellar plasma

    Science.gov (United States)

    Hammoud, M.; El Eid, M.; Darwish, M.

    2017-06-01

    An important phenomenon in Astrophysics is the process of magnetic reconnection (MGR), which is envisaged to understand the solar flares, coronal mass ejection, interaction of the solar wind with the Earth’s magnetic field (so called geomagnetic storm) and other phenomena. In addition, it plays a role in the formation of stars. MGR involves topological change of a set of magnetic field lines leading to a new equilibrium configuration of lower magnetic energy. The MGR is basically described in the framework of the Maxwell’s equations linked to Navier-Stockes equations. Nevertheless, many details are still not understood. In this paper, we investigate the MGR process in the framework of the Magnetohydrodynamic (MHD) model of a single conducting fluid using a modern powerful computational tool (OpenFOAM). We will show that the MGR process takes place only if resistivity exists. However, despite the high conductivity of the plasma, resistivity becomes effective in a very thin layer generating sharp gradients of the magnetic field, and thus accelerating the reconnection process. The net effect of MGR is that magnetic energy is converted into thermal and kinetic energies leading to heating and acceleration of charged particles. The Sun’s coronal ejection is an example of the MGR process.

  2. Kinetic intermittency in magnetized plasma turbulence

    CERN Document Server

    Teaca, Bogdan; Told, Daniel; Jenko, Frank

    2016-01-01

    We employ magnetized plasma turbulence, described by a gyrokinetic formalism in an interval ranging from the end of the fluid scales to the electron gyroradius, to introduce the first study of kinetic intermittency, in which nonlinear structures formed directly in the distribution functions are analyzed by accounting for velocity space correlations generated by linear (Landau resonance) and nonlinear phase mixing. Electron structures are found to be strongly intermittent and dominated by linear phase mixing, while nonlinear phase mixing dominates the weakly intermittent ions. This is the first time spatial intermittency and linear phase mixing are shown to be self-consistently linked for the electrons and, as the magnetic field follows the intermittency of the electrons at small scales, explain why magnetic islands are places dominated by Landau damping in steady state turbulence.

  3. Solar Flare Magnetic Fields and Plasmas

    CERN Document Server

    Fisher, George

    2012-01-01

    This volume is devoted to the dynamics and diagnostics of solar magnetic fields and plasmas in the Sun’s atmosphere. Five broad areas of current research in Solar Physics are presented: (1) New techniques for incorporating radiation transfer effects into three-dimensional magnetohydrodynamic models of the solar interior and atmosphere, (2) The connection between observed radiation processes occurring during flares and the underlying flare energy release and transport mechanisms, (3) The global balance of forces and momenta that occur during flares, (4) The data-analysis and theoretical tools needed to understand and assimilate vector magnetogram observations and (5) Connecting flare and CME phenomena to the topological properties of the magnetic field in the Solar Atmosphere. The role of the Sun’s magnetic field is a major emphasis of this book, which was inspired by a workshop honoring Richard C. (Dick) Canfield.  Dick has been making profound contributions to these areas of research over a long and pro...

  4. Collisionless Magnetic Reconnection in Space Plasmas

    Directory of Open Access Journals (Sweden)

    Rudolf A. Treumann

    2013-12-01

    Full Text Available Magnetic reconnection, the merging of oppositely directed magnetic fields that leads to field reconfiguration, plasma heating, jetting and acceleration, is one of the most celebrated processes in collisionless plasmas. It requires the violation of the frozen-in condition which ties gyrating charged particles to the magnetic field inhibiting diffusion. Ongoing reconnection has been identified in near-Earth space as being responsible for the excitation of substorms, magnetic storms, generation of field aligned currents and their consequences, the wealth of auroral phenomena. Its theoretical understanding is now on the verge of being completed. Reconnection takes place in thin current sheets. Analytical concepts proceeded gradually down to the microscopic scale, the scale of the electron skin depth or inertial length, recognizing that current layers that thin do preferentially undergo spontaneous reconnection. Thick current layers start reconnecting when being forced by plasma inflow to thin. For almost half a century the physical mechanism of reconnection has remained a mystery. Spacecraft in situ observations in combination with sophisticated numerical simulations in two and three dimensions recently clarified the mist, finding that reconnection produces a specific structure of the current layer inside the electron inertial (also called electron diffusion region around the reconnection site, the X line. Onset of reconnection is attributed to pseudo-viscous contributions of the electron pressure tensor aided by electron inertia and drag, creating a complicated structured electron current sheet, electric fields, and an electron exhaust extended along the current layer. We review the general background theory and recent developments in numerical simulation on collisionless reconnection. It is impossible to cover the entire field of reconnection in a short space-limited review. The presentation necessarily remains cursory, determined by our taste

  5. On the formation of collapsed superdense nuclei in the universe

    Science.gov (United States)

    Teruaki, Ohnishi

    1981-06-01

    The possibility of the production of putative superdense nuclei (SDNs) in the universe is studied with the assumption that the SDNs can certainly be formed when nucleons are compressed over some critical density. Possible nuclear astrophysical processes for SDN production taking place in the early big-bang universe, in interstellar space and in ejection from neutron stars are investigated. It is found that the SDNs cannot be produced at all in a hot universe regardless of the properties of SDNs. The situation that would occur in a cold universe is also discussed. A finite amount of SDNs is found to be formed in interstellar space as the product of high-energy reactions between primary cosmic rays and interstellar matter. It also becomes clear that the astration of SDNs thus formed plays no essential role for the enhancement of the number of SDNs. On the other hand, the SDNs originating from neutron stars are estimated to have a cosmic abundance relative to Si as high as 8 × 10-8--5, which is, apparently, in contradiction with observations. Some implications of this are discussed.

  6. Low-frequency fluctuations in plasma magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Cable, S.; Tajima, T.

    1992-02-01

    It is shown that even a non-magnetized plasma with temperature T sustains zero-frequency magnetic fluctuations in thermal equilibrium. Fluctuations in electric and magnetic fields, as well as in densities, are computed. Four cases are studied: a cold, gaseous, isotropic, non-magnetized plasma; a cold, gaseous plasma in a uniform magnetic field; a warm, gaseous plasma described by kinetic theory; and a degenerate electron plasma. For the simple gaseous plasma, the fluctuation strength of the magnetic field as a function of frequency and wavenumber is calculated with the aid of the fluctuation-dissipation theorem. This calculation is done for both collisional and collisionless plasmas. The magnetic field fluctuation spectrum of each plasma has a large zero-frequency peak. The peak is a Dirac {delta}-function in the collisionless plasma; it is broadened into a Lorentzian curve in the collisional plasma. The plasma causes a low frequency cutoff in the typical black-body radiation spectrum, and the energy under the discovered peak approximates the energy lost in this cutoff. When the imposed magnetic field is weak, the magnetic field were vector fluctuation spectra of the two lowest modes are independent of the strength of the imposed field. Further, these modes contain finite energy even when the imposed field is zero. It is the energy of these modes which forms the non-magnetized zero-frequency peak of the isotropic plasma. In deriving these results, a simple relationship between the dispersion relation and the fluctuation power spectrum of electromagnetic waves if found. The warm plasma is shown, by kinetic theory, to exhibit a zero-frequency peak in its magnetic field fluctuation spectrum as well. For the degenerate plasma, we find that electric field fluctuations and number density fluctuations vanish at zero frequency; however, the magnetic field power spectrum diverges at zero frequency.

  7. Experimental investigation of plasma relaxation using a compact coaxial magnetized plasma gun in a background plasma

    Science.gov (United States)

    Zhang, Yue; Lynn, Alan; Gilmore, Mark; Hsu, Scott; University of New Mexico Collaboration; Los Alamos National Laboratory Collaboration

    2013-10-01

    A compact coaxial plasma gun is employed for experimental studies of plasma relaxation in a low density background plasma. Experiments are being conducted in the linear HelCat device at UNM. These studies will advance the knowledge of basic plasma physics in the areas of magnetic relaxation and space and astrophysical plasmas, including the evolution of active galactic jets/radio lobes within the intergalactic medium. The gun is powered by a 120pF ignitron-switched capacitor bank which is operated in a range of 5-10 kV and ~100 kA. Multiple diagnostics are employed to investigate plasma relaxation process. Magnetized Argon plasma bubbles with velocities ~1.2Cs and densities ~1020 m-3 have been achieved. Different distinct regimes of operation with qualitatively different dynamics are identified by fast CCD camera images, with the parameter determining the operation regime. Additionally, a B-dot probe array is employed to measure the spatial toroidal and poloidal magnetic flux evolution to identify detached plasma bubble configurations. Experimental data and analysis will be presented.

  8. Parametric instabilities in magnetized bi-ion and dusty plasmas

    Indian Academy of Sciences (India)

    The excitation of low frequency modes of oscillations in a magnetized bi-ion or dusty plasma with parametric pumping of the magnetic field is analysed. The equation of motion governing the perturbed plasma is derived and parametrically excited transverse modes propagating along the magnetic field are found.

  9. Intense Magnetized Plasma-Wall Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Bruno S. [UNR; Fuelling, Stephan [UNR

    2013-11-30

    This research project studied wall-plasma interactions relevant to fusion science. Such interactions are a critical aspect of Magneto-Inertial Fusion (MIF) because flux compression by a pusher material, in particular the metal for the liner approach to MIF, involves strong eddy current heating on the surface of the pusher, and probably interactions and mixing of the pusher with the interior fuel during the time when fusion fuel is being burned. When the pusher material is a metal liner, high-energy-density conditions result in fascinating behavior. For example, "warm dense matter" is produced, for which material properties such as resistivity and opacity are not well known. In this project, the transformation into plasma of metal walls subjected to pulsed megagauss magnetic fields was studied with an experiment driven by the UNR 1 MA Zebra generator. The experiment was numerically simulated with using the MHRDR code. This simple, fundamental high-energy-density physics experiment, in a regime appropriate to MIF, has stimulated an important and fascinating comparison of numerical modeling codes and tables with experiment. In addition, we participated in developing the FRCHX experiment to compress a field-reversed-configuration (FRC) plasma with a liner, in collaboration with researchers from Air Force Research Laboratory and Los Alamos National Lab, and we helped develop diagnostics for the Plasma Liner Experiment (PLX) at LANL. Last, but not least, this project served to train students in high-energy-density physics.

  10. Plasma transport in the Scrape-off-Layer of magnetically confined plasma and the plasma exhaust

    DEFF Research Database (Denmark)

    Rasmussen, Jens Juul; Naulin, Volker; Nielsen, Anders Henry

    An overview of the plasma dynamics in the Scrape-off-Layer (SOL) of magnetically confined plasma is presented. The SOL is the exhaust channel of the warm plasma from the core, and the understanding of the SOL plasma dynamics is one of the key issues in contemporary fusion research. It is essential...... for operation of fusion experiments and ultimately fusion power plants. Recent results clearly demonstrate that the plasma transport through the SOL is dominated by turbulent intermittent fluctuations organized into filamentary structures convecting particles, energy, and momentum through the SOL region. Thus......, the transport cannot be described and parametrized by simple diffusive type models. The transport leads to strong localized power loads on the first wall and the plasma facing components, which have serious lasting influence....

  11. Magnetic configuration control of ITER plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Albanese, R.; Mattei, M. [Assoc. Euratom-ENEA-CREATE, Univ. Mediterranea RC, Loc. Feo di Vito I-89060, RC (Italy); Portone, A. [EFDA-CSU, Max Planck Institute for Plasmaphysics, Boltzmannstrasse 2, D-85748 Garching (Germany)], E-mail: alfredo.portone@tech.efda.org; Ambrosino, G. [Assoc. Euratom-ENEA-CREATE, University Napoli Federico II, Via Claudio 21, I-80125 Naples (Italy); Artaserse, G. [Assoc. Euratom-ENEA-CREATE, Univ. Mediterranea RC, Loc. Feo di Vito I-89060, RC (Italy); Crisanti, F. [Associazione EURATOM-ENEA sulla Fusione, Frascati, C.P. 65, 00044-Frascati (Italy); De Tommasi, G. [Assoc. Euratom-ENEA-CREATE, University Napoli Federico II, Via Claudio 21, I-80125 Naples (Italy); Fresa, R. [DIFA, University della Basilicata, Contrada Macchia Romana I-85100, PZ (Italy); Sartori, F. [Euratom/UKAEA Fusion Assoc., Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Villone, F. [Assoc. Euratom-ENEA-CREATE, University Cassino, Via Di Biasio 43, I-03043 Cassino (Italy)

    2007-10-15

    The aim of this paper is to present some new tools used to review the capability of the ITER Poloidal Field (PF) system in controlling the broad range of plasma configurations presently forecasted during ITER operation. The attention is focused on the axi-symmetric aspects of plasma magnetic configuration control since they pose the greatest challenges in terms of control power and they have the largest impact on machine capital cost. Some preliminary results obtained during ongoing activities in collaboration between ENEA/CREATE and EFDA are presented. The paper is divided in two main parts devoted, respectively, to the presentation of a procedure for the PF current optimisation during the scenario, and of a software environment for the study of the PF system capabilities using the plasma linearized response. The proposed PF current optimisation procedure is then used to assess Scenario 2 design, also taking into account the presence of axisymmetric eddy currents and possible variations of poloidal beta and internal inductance. The numerical linear model based tool derived from the JET oriented eXtreme Shape Controller (XSC) tools is finally used to obtain results on the strike point sweeping in ITER.

  12. Parametric instabilities in magnetized bi-ion and dusty plasmas

    Indian Academy of Sciences (India)

    Email: n.cramer@physics.usyd.edu.au. MS received 1 April 2003; accepted 31 July 2003. Abstract. The excitation of low frequency modes of oscillations in a magnetized bi-ion or dusty plasma with parametric pumping of the magnetic field is analysed. The equation of motion governing the perturbed plasma is derived and ...

  13. Low-frequency fluctuations in a pure toroidal magnetized plasma

    Indian Academy of Sciences (India)

    A magnetized, low- plasma in pure toroidal configuration is formed and extensively studied with ion mass as control parameter. Xenon, krypton and argon plasmas are formed at a fixed toroidal magnetic field of 0.024 T, with a peak density of ∼ 1011 cm-3, ∼ 4 × 1010 cm-3 and ∼ 2 × 1010 cm−3 respectively.

  14. The Physics of Ion Decoupling in Magnetized Plasma Explosions

    Energy Technology Data Exchange (ETDEWEB)

    Hewett, D; Larson, D; Brecht, S

    2011-02-08

    When a finite pulse of plasma expands into a magnetized background plasma, MHD predicts the pulse expel background plasma and its B-field - i.e. cause a magnetic 'bubble'. The expanding plasma is confined within the bubble, later to escape down the B-field lines. MHD suggests that the debris energy goes to expelling the B-field from the bubble volume and kinetic energy of the displaced background. For HANEs, this is far from the complete story. For many realistic HANE regimes, the long mean-free-path for collisions necessitates a Kinetic Ion Simulation Model (KISM). The most obvious effect is that the debris plasma can decouple and slip through the background plasma. The implications are: (1) the magnetic bubble is not as large as expected and (2) the debris is no longer confined within the magnetic bubble.

  15. Electromagnetic radiation by quark-gluon plasma in magnetic field

    OpenAIRE

    Tuchin, Kirill

    2012-01-01

    The electromagnetic radiation by quark-gluon plasma in strong magnetic field is calculated. The contributing processes are synchrotron radiation and one--photon annihilation. It is shown that in relativistic heavy--ion collisions at RHIC and LHC synchrotron radiation dominates over the annihilation. Moreover, it constitutes a significant part of all photons produced by the plasma at low transverse momenta; its magnitude depends on the plasma temperature and the magnetic field strength. Electr...

  16. Magnetic susceptibility and Landau diamagnetism of quantum collisional plasma

    Science.gov (United States)

    Latyshev, A. V.; Yushkanov, A. A.

    2017-04-01

    Quantum collisional plasma with an arbitrary degree of degeneracy of the electron gas is considered. Using the exact expression for the transverse electric conductivity of quantum collisional plasma, the magnetic susceptibility is described using the kinetic approach and a formula for calculating Landau diamagnetism is derived. Quantum Maxwellian plasma is considered as a special case. To this end, in the formulas derived, the limit is taken for the chemical potential tending to minus infinity. The properties of the magnetic susceptibility of quantum plasma are compared to those of degenerate and Maxwellian plasmas.

  17. Plasma membrane isolation using immobilized concanavalin A magnetic beads.

    Science.gov (United States)

    Lee, Yu-Chen; Srajer Gajdosik, Martina; Josic, Djuro; Lin, Sue-Hwa

    2012-01-01

    Isolation of highly purified plasma membranes is the key step in constructing the plasma membrane proteome. Traditional plasma membrane isolation method takes advantage of the differential density of organelles. While differential centrifugation methods are sufficient to enrich for plasma membranes, the procedure is lengthy and results in low recovery of the membrane fraction. Importantly, there is significant contamination of the plasma membranes with other organelles. The traditional agarose affinity matrix is suitable for isolating proteins but has limitation in separating organelles due to the density of agarose. Immobilization of affinity ligands to magnetic beads allows separation of affinity matrix from organelles through magnets and could be developed for the isolation of organelles. We have developed a simple method for isolating plasma membranes using lectin concanavalin A (ConA) magnetic beads. ConA is immobilized onto magnetic beads by binding biotinylated ConA to streptavidin magnetic beads. The ConA magnetic beads are used to bind glycosylated proteins present in the membranes. The bound membranes are solubilized from the magnetic beads with a detergent containing the competing sugar alpha methyl mannoside. In this study, we describe the procedure of isolating rat liver plasma membranes using sucrose density gradient centrifugation as described by Neville. We then further purify the membrane fraction by using ConA magnetic beads. After this purification step, main liver plasma membrane proteins, especially the highly glycosylated ones and proteins containing transmembrane domains could be identified by LC-ESI-MS/MS. While not described here, the magnetic bead method can also be used to isolate plasma membranes from cell lysates. This membrane purification method should expedite the cataloging of plasma membrane proteome.

  18. Electromagnetic solitary pulses in a magnetized electron-positron plasma.

    Science.gov (United States)

    Shukla, P K; Eliasson, B; Stenflo, L

    2011-09-01

    A theory for large amplitude compressional electromagnetic solitary pulses in a magnetized electron-positron (e-p) plasma is presented. The pulses, which propagate perpendicular to the external magnetic field, are associated with the compression of the plasma density and the wave magnetic field. Here the solitary wave magnetic field pressure provides the restoring force, while the inertia comes from the equal mass electrons and positrons. The solitary pulses are formed due to a balance between the compressional wave dispersion arising from the curl of the inertial forces in Faraday's law and the nonlinearities associated with the divergence of the electron and positron fluxes, the nonlinear Lorentz forces, the advection of the e-p fluids, and the nonlinear plasma current densities. The compressional solitary pulses can exist in a well-defined speed range above the Alfvén speed. They can be associated with localized electromagnetic field excitations in magnetized laboratory and space plasmas composed of electrons and positrons.

  19. Wave propagation in a strongly coupled magnetized plasma

    Science.gov (United States)

    Reynolds, Alexi; Kählert, Hanno; Bonitz, Michael

    2011-10-01

    Strongly coupled plasmas play a growing role in many fields of physics--from dusty plasmas to compact stars and the quark-gluon plasma, e.g.. In many cases these plasmas are subject to a strong magnetic field. The one-component plasma (OCP) model is often used to theoretically analyze strong plasma correlations. Here the wave propagation in a strongly coupled OCP subject to an external magnetic field is investigated by means of the quasi- localized charge approximation. The dispersion relation and the wave polarization are studied for wave propagation across and along the magnetic field as well as for arbitrary directions of the wave vector. Support by the Deutsche Forschungsgemeinschaft via SFB-TR 24 and DAAD via the RISE program is acknowledged.

  20. Studies of Magnetic Reconnection in Colliding Laser-Produced Plasmas

    Science.gov (United States)

    Rosenberg, Michael

    2013-10-01

    Novel images of magnetic fields and measurements of electron and ion temperatures have been obtained in the magnetic reconnection region of high- β, laser-produced plasmas. Experiments using laser-irradiated foils produce expanding, hemispherical plasma plumes carrying MG Biermann-battery magnetic fields, which can be driven to interact and reconnect. Thomson-scattering measurements of electron and ion temperatures in the interaction region of two colliding, magnetized plasmas show no thermal enhancement due to reconnection, as expected for β ~ 8 plasmas. Two different proton radiography techniques used to image the magnetic field structures show deformation, pileup, and annihilation of magnetic flux. High-resolution images reveal unambiguously reconnection-induced jets emerging from the interaction region and show instabilities in the expanding plasma plumes and supersonic, hydrodynamic jets due to the plasma collision. Quantitative magnetic flux data show that reconnection in experiments with asymmetry in the scale size, density, temperature, and plasma flow across the reconnection region occurs less efficiently than in similar, symmetric experiments. This result is attributed to disruption of the Hall mechanism mediating collisionless reconnection. The collision of plasmas carrying parallel magnetic fields has also been probed, illustrating the deformation of magnetic field structures in high-energy-density plasmas in the absence of reconnection. These experiments are particularly relevant to high- β reconnection environments, such as the magnetopause. This work was performed in collaboration with C. Li, F. Séguin, A. Zylstra, H. Rinderknecht, H. Sio, J. Frenje, and R. Petrasso (MIT), I. Igumenshchev, V. Glebov, C. Stoeckl, and D. Froula (LLE), J. Ross and R. Town (LLNL), W. Fox (UNH), and A. Nikroo (GA), and was supported in part by the NLUF, FSC/UR, U.S. DOE, LLNL, and LLE.

  1. Multi-Scale Investigation of Sheared Flows In Magnetized Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Edward, Jr., Thomas [Auburn Univ., Auburn, AL (United States)

    2014-09-19

    Flows parallel and perpendicular to magnetic fields in a plasma are important phenomena in many areas of plasma science research. The presence of these spatially inhomogeneous flows is often associated with the stability of the plasma. In fusion plasmas, these sheared flows can be stabilizing while in space plasmas, these sheared flows can be destabilizing. Because of this, there is broad interest in understanding the coupling between plasma stability and plasma flows. This research project has engaged in a study of the plasma response to spatially inhomogeneous plasma flows using three different experimental devices: the Auburn Linear Experiment for Instability Studies (ALEXIS) and the Compact Toroidal Hybrid (CTH) stellarator devices at Auburn University, and the Space Plasma Simulation Chamber (SPSC) at the Naval Research Laboratory. This work has shown that there is a commonality of the plasma response to sheared flows across a wide range of plasma parameters and magnetic field geometries. The goal of this multi-device, multi-scale project is to understand how sheared flows established by the same underlying physical mechanisms lead to different plasma responses in fusion, laboratory, and space plasmas.

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

    Science.gov (United States)

    Griffin, Steven T.

    2003-01-01

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

  3. Electron energy distributions in a magnetized inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Song, Sang-Heon, E-mail: ssongs@umich.edu, E-mail: Sang-Heon.Song@us.tel.com [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, Michigan 48109-2104 (United States); Yang, Yang, E-mail: yang-yang@amat.com [Applied Materials Inc., 974 E. Arques Avenue, M/S 81312, Sunnyvale, California 94085 (United States); Chabert, Pascal, E-mail: pascal.chabert@lpp.polytechnique.fr [LPP, CNRS, Ecole Polytechnique, UPMC, Paris XI, 91128 Palaiseau (France); Kushner, Mark J., E-mail: mjkush@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109-2122 (United States)

    2014-09-15

    Optimizing and controlling electron energy distributions (EEDs) is a continuing goal in plasma materials processing as EEDs determine the rate coefficients for electron impact processes. There are many strategies to customize EEDs in low pressure inductively coupled plasmas (ICPs), for example, pulsing and choice of frequency, to produce the desired plasma properties. Recent experiments have shown that EEDs in low pressure ICPs can be manipulated through the use of static magnetic fields of sufficient magnitudes to magnetize the electrons and confine them to the electromagnetic skin depth. The EED is then a function of the local magnetic field as opposed to having non-local properties in the absence of the magnetic field. In this paper, EEDs in a magnetized inductively coupled plasma (mICP) sustained in Ar are discussed with results from a two-dimensional plasma hydrodynamics model. Results are compared with experimental measurements. We found that the character of the EED transitions from non-local to local with application of the static magnetic field. The reduction in cross-field mobility increases local electron heating in the skin depth and decreases the transport of these hot electrons to larger radii. The tail of the EED is therefore enhanced in the skin depth and depressed at large radii. Plasmas densities are non-monotonic with increasing pressure with the external magnetic field due to transitions between local and non-local kinetics.

  4. Occurrence of Equatorial Plasma Bubbles during Intense Magnetic Storms

    Directory of Open Access Journals (Sweden)

    Chao-Song Huang

    2011-01-01

    Full Text Available An important issue in low-latitude ionospheric space weather is how magnetic storms affect the generation of equatorial plasma bubbles. In this study, we present the measurements of the ion density and velocity in the evening equatorial ionosphere by the Defense Meteorological Satellite Program (DMSP satellites during 22 intense magnetic storms. The DMSP measurements show that deep ion density depletions (plasma bubbles are generated after the interplanetary magnetic field (IMF turns southward. The time delay between the IMF southward turning and the first DMSP detection of plasma depletions decreases with the minimum value of the IMF Bz, the maximum value of the interplanetary electric field (IEF Ey, and the magnitude of the Dst index. The results of this study provide strong evidence that penetration electric field associated with southward IMF during the main phase of magnetic storms increases the generation of equatorial plasma bubbles in the evening sector.

  5. Penetration of Magnetosheath Plasma into Dayside Magnetosphere. 2. ; Magnetic Field in Plasma Filaments

    Science.gov (United States)

    Lyatsky, Wladislaw; Pollock, Craig; Goldstein, Melvyn L.; Lyatskaya, Sonya Inna; Avanov, Levon Albert

    2016-01-01

    In this paper, we examined plasma structures (filaments), observed in the dayside magnetosphere but containing magnetosheath plasma. These filaments show the stable antisunward motion (while the ambient magnetospheric plasma moved in the opposite direction) and the existence of a strip of magnetospheric plasma, separating these filaments from the magnetosheath. These results, however, contradict both theoretical studies and simulations by Schindler (1979), Ma et al. (1991), Dai and Woodward (1994, 1998), and other researchers, who reported that the motion of such filaments through the magnetosphere is possible only when their magnetic field is directed very close to the ambient magnetic field, which is not the situation that is observed. In this study, we show that this seeming contradiction may be related to different events as the theoretical studies and simulations are related to the case when the filament magnetic field is about aligned with filament orientation, whereas the observations show that the magnetic field in these filaments may be rotating. In this case, the rotating magnetic field, changing incessantly its direction, drastically affects the penetration of plasma filaments into the magnetosphere. In this case, the filaments with rotating magnetic field, even if in each moment it is significantly inclined to the ambient magnetic field, may propagate through the magnetosphere, if their average (for the rotation period) magnetic field is aligned with the ambient magnetic field. This shows that neglecting the rotation of magnetic field in these filaments may lead to wrong results.

  6. Magnetic field generation via parametric instabilities in collisional plasmas

    Science.gov (United States)

    Katoh, K.

    1982-06-01

    A formalism for the parametric instability with low-frequency magnetic field generation in a collisional plasma is developed. The spontaneous low-frequency magnetic field results from a resonant decay instability of an intense pump wave into a magneto-static wave which appears only in a collisional plasma. The growth rate for a resonant decay instability of an intense electromagnetic wave into a Langmuir wave and a magneto-static wave is obtained.

  7. Simulating Magnetized Laboratory Plasmas with Smoothed Particle Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Jeffrey N. [Univ. of California, Davis, CA (United States)

    2009-01-01

    The creation of plasmas in the laboratory continues to generate excitement in the physics community. Despite the best efforts of the intrepid plasma diagnostics community, the dynamics of these plasmas remains a difficult challenge to both the theorist and the experimentalist. This dissertation describes the simulation of strongly magnetized laboratory plasmas with Smoothed Particle Hydrodynamics (SPH), a method born of astrophysics but gaining broad support in the engineering community. We describe the mathematical formulation that best characterizes a strongly magnetized plasma under our circumstances of interest, and we review the SPH method and its application to astrophysical plasmas based on research by Phillips [1], Buerve [2], and Price and Monaghan [3]. Some modifications and extensions to this method are necessary to simulate terrestrial plasmas, such as a treatment of magnetic diffusion based on work by Brookshaw [4] and by Atluri [5]; we describe these changes as we turn our attention toward laboratory experiments. Test problems that verify the method are provided throughout the discussion. Finally, we apply our method to the compression of a magnetized plasma performed by the Compact Toroid Injection eXperiment (CTIX) [6] and show that the experimental results support our computed predictions.

  8. Neutrino-electron scattering in a dense strongly magnetized plasma

    Directory of Open Access Journals (Sweden)

    Kuznetsov Alexander

    2017-01-01

    Full Text Available We investigate the process of neutrino-electron scattering in a dense plasma and magnetic field of arbitrary strength, where electrons can occupy the states corresponding to excited Landau levels. We calculate the total probability of this process, summarized over all initial states of the plasma electrons which is only physically meaningful. Possible astrophysical manifestations of the process are briefly discussed.

  9. Dynamics of magnetized plasma sheaths around a trench

    Energy Technology Data Exchange (ETDEWEB)

    Hatami, M. M., E-mail: m-hatami@kntu.ac.ir [Physics Department, K. N. Toosi University of Technology, 15418-49611 Tehran (Iran, Islamic Republic of)

    2016-08-15

    Considering a magnetized plasma sheath, the temporal evolution of the ion properties (the incident ion flux, the ion impact angle, and the incident ion dose) around a rectangular trench is studied numerically. Our results show that the ion flux along the bottom surface greatly reduces in the presence of magnetic field and its uniformity improves, but the magnetic field does not considerably affect the ion flux along the sidewall. In addition, the thickness of the plasma sheath increases by increasing the magnetic field while its conformality to the target surface reduces faster. Moreover, it is shown that any increase in the magnitude (inclination angle) of the magnetic field causes a decrease (an increase) in the angle of incidence of ions on the bottom and sidewall surfaces. Furthermore, in the presence of magnetic field, the ions strike nearly normal to the surface of the bottom while they become less oblique along the sidewall surface. In addition, contrary to the corners of the trench, it is found that the magnetic field greatly affects the incident ion dose at the center of the trench surfaces. Also, it is shown that the incident ion dose along the sidewall is the highest near the center of the sidewall in both magnetized and magnetic-free cases. However, uniformity of the incident ion dose along the sidewall is better than that along the bottom in both magnetized and unmagnetized plasma sheath.

  10. Electric and magnetic wakefields in a plasma channel

    Directory of Open Access Journals (Sweden)

    Pallavi Jha

    2005-07-01

    Full Text Available A detailed analytical study of plasma wakefield generation in a wide parabolic plasma channel is reported. A perturbative technique involving orders of the incident laser beam and the effects of inhomogeneity of the plasma density is used to obtain explicit electric as well as magnetic wakefields. The axial and transverse forces acting on a test electron due to the wakefields have been evaluated.

  11. Magnetic-surface quality in nonaxisymmetric plasma equilibria.

    Science.gov (United States)

    Nührenberg, Carolin; Boozer, Allen H; Hudson, Stuart R

    2009-06-12

    The confinement of plasmas by magnetic fields with nonaxisymmetric shaping can be degraded or destroyed by the breakup of the magnetic surfaces through effects that are intrinsic to the shaping. An efficient perturbation method of determining this drive for islands was developed and applied to stellarator equilibria.

  12. Endogenous magnetic reconnection and associated high energy plasma processes

    Science.gov (United States)

    Coppi, B.; Basu, B.

    2018-02-01

    An endogenous reconnection process involves a driving factor that lays inside the layer where a drastic change of magnetic field topology occurs. A process of this kind is shown to take place when an electron temperature gradient is present in a magnetically confined plasma and the evolving electron temperature fluctuations are anisotropic. The width of the reconnecting layer remains significant even when large macroscopic distances are considered. In view of the fact that there are plasmas in the Universe with considerable electron thermal energy contents this feature can be relied upon in order to produce generation or conversion of magnetic energy, high energy particle populations and momentum and angular momentum transport.

  13. Neutrino-driven electrostatic instabilities in a magnetized plasma

    Science.gov (United States)

    Haas, Fernando; Pascoal, Kellen Alves; Mendonça, José Tito

    2017-07-01

    The destabilizing role of neutrino beams on the Trivelpiece-Gould modes is considered, assuming electrostatic perturbations in a magnetized plasma composed by electrons in a neutralizing ionic background, coupled to a neutrino species by means of an effective neutrino force arising from the electroweak interaction. The magnetic field is found to significantly improve the linear instability growth rate, as calculated for supernova type II environments. On the formal level, for wave vectors parallel or perpendicular to the magnetic field, the instability growth rate is found from the unmagnetized case replacing the plasma frequency by the appropriated Trivelpiece-Gould frequency. The growth rate associated with oblique propagation is also obtained.

  14. MHD Simulations of the Plasma Flow in the Magnetic Nozzle

    Science.gov (United States)

    Smith, T. E. R.; Keidar, M.; Sankaran, K.; olzin, K. A.

    2013-01-01

    The magnetohydrodynamic (MHD) flow of plasma through a magnetic nozzle is simulated by solving the governing equations for the plasma flow in the presence of an static magnetic field representing the applied nozzle. This work will numerically investigate the flow and behavior of the plasma as the inlet plasma conditions and magnetic nozzle field strength are varied. The MHD simulations are useful for addressing issues such as plasma detachment and to can be used to gain insight into the physical processes present in plasma flows found in thrusters that use magnetic nozzles. In the model, the MHD equations for a plasma, with separate temperatures calculated for the electrons and ions, are integrated over a finite cell volume with flux through each face computed for each of the conserved variables (mass, momentum, magnetic flux, energy) [1]. Stokes theorem is used to convert the area integrals over the faces of each cell into line integrals around the boundaries of each face. The state of the plasma is described using models of the ionization level, ratio of specific heats, thermal conductivity, and plasma resistivity. Anisotropies in current conduction due to Hall effect are included, and the system is closed using a real-gas equation of state to describe the relationship between the plasma density, temperature, and pressure.A separate magnetostatic solver is used to calculate the applied magnetic field, which is assumed constant for these calculations. The total magnetic field is obtained through superposition of the solution for the applied magnetic field and the self-consistently computed induced magnetic fields that arise as the flowing plasma reacts to the presence of the applied field. A solution for the applied magnetic field is represented in Fig. 1 (from Ref. [2]), exhibiting the classic converging-diverging field pattern. Previous research was able to demonstrate effects such as back-emf at a super-Alfvenic flow, which significantly alters the shape of the

  15. Implicit Methods for the Magnetohydrodynamic Description of Magnetically Confined Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Jardin, S C

    2010-09-28

    Implicit algorithms are essential for predicting the slow growth and saturation of global instabilities in today’s magnetically confined fusion plasma experiments. Present day algorithms for obtaining implicit solutions to the magnetohydrodynamic (MHD) equations for highly magnetized plasma have their roots in algorithms used in the 1960s and 1970s. However, today’s computers and modern linear and non-linear solver techniques make practical much more comprehensive implicit algorithms than were previously possible. Combining these advanced implicit algorithms with highly accurate spatial representations of the vector fields describing the plasma flow and magnetic fields and with improved methods of calculating anisotropic thermal conduction now makes possible simulations of fusion experiments using realistic values of plasma parameters and actual configuration geometry.

  16. Collimation of laser-produced plasmas using axial magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Amitava; Harilal, Sivanandan S.; Hassan, Syed M.; Endo, Akira; Mocek, Tomas; Hassanein, A.

    2015-06-01

    We investigated the expansion dynamics of laser-produced plasmas expanding into an axial magnetic field. Plasmas were generated by focusing 1.064 µm Nd:YAG laser pulses onto a planar tin target in vacuum and allowed to expand into a 0.5 T magnetic-filed where field lines were aligned along the plume expansion direction. Gated images employing intensified CCD showed focusing of the plasma plume, which were also compared with results obtained using particle-in-cell modelling methods. The estimated density and temperature of the plasma plumes employing emission spectroscopy revealed significant changes in the presence and absence of the 0.5T magnetic field. In the presence of the field, the electron temperature is increased with distance from the target, while the density showed opposite effects.

  17. Apparatus for magnetic and electrostatic confinement of plasma

    Science.gov (United States)

    Rostoker, Norman [Irvine, CA; Binderbauer, Michl [Irvine, CA

    2009-08-04

    An apparatus and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions ions are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

  18. Apparatus for magnetic and electrostatic confinement of plasma

    Energy Technology Data Exchange (ETDEWEB)

    Rostoker, Norman; Binderbauer, Michl

    2016-07-05

    An apparatus and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions ions are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

  19. Passive Spectroscopic Diagnostics for Magnetically-confined Fusion Plasmas

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-18

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

  20. Current-vortex filaments in magnetized plasmas

    NARCIS (Netherlands)

    Bergmans, J.; Kuvshinov, B. N.; Lakhin, V. P.; Schep, T. J.; Westerhof, E.

    1999-01-01

    Current-vortex filament solutions to the two-fluid plasma equations that describe drift-Alfven waves are presented. Such filament systems are Hamiltonian. Integrable three and four filament systems are discussed in some detail. A wide variety of orbit topologies exists in the plasma case. Special

  1. Effect of solenoidal magnetic field on drifting laser plasma

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Kazumasa; Sekine, Megumi [Tokyo Institute of Technology, Yokohama 226-8502 (Japan); Okamura, Masahiro [Brookhaven National Laboratory, Upton, NY 11973 (United States) and RIKEN, Wako-shi, Saitama 351-0198 (United States); Cushing, Eric [Pennsylvania State University, University Park, PA 16802 (United States); Jandovitz, Peter [Cornell University, Ithaca, NY 14853 (United States)

    2013-04-19

    An ion source for accelerators requires to provide a stable waveform with a certain pulse length appropriate to the application. The pulse length of laser ion source is easy to control because it is expected to be proportional to plasma drifting distance. However, current density decay is proportional to the cube of the drifting distance, so large current loss will occur under unconfined drift. We investigated the stability and current decay of a Nd:YAG laser generated copper plasma confined by a solenoidal field using a Faraday cup to measure the current waveform. It was found that the plasma was unstable at certain magnetic field strengths, so a baffle was introduced to limit the plasma diameter at injection and improve the stability. Magnetic field, solenoid length, and plasma diameter were varied in order to find the conditions that minimize current decay and maximize stability.

  2. Collisionless Interaction of a Magnetized Ambient Plasma and a Field-Parallel Laser Produced Plasma

    Science.gov (United States)

    Heuer, P. V.; Bondarenko, A. S.; Schaeffer, D. B.; Constantin, C. G.; Vincena, S.; Tripathi, S.; Gekelman, W.; Weidl, M.; Winske, D.; Niemann, C.

    2016-10-01

    We present measurements of the collisionless coupling between an exploding laser-produced plasma (LPP) and a large, magnetized ambient plasma. The LPP was created by focusing the Raptor laser (400 J, 40 ns) on a planar plastic target embedded in the ambient Large Plasma Device (LAPD) plasma at the University of California, Los Angeles. The resulting ablated material moved parallel to the background magnetic field, interacting with the ambient plasma along the full 17m length of the LAPD. The amplitude and polarization of waves driven by the interaction were measured by an array of 3-axis magnetic flux probes. Emissive doppler spectroscopy and a high temporal resolution monochrometer were used to observe the velocity and charge state distributions of both ambient and debris ions. Measurements are compared to hybrid simulations of quasi-parallel shocks.

  3. Optimal Design of Magnetic ComponentsinPlasma Cutting Power Supply

    Science.gov (United States)

    Jiang, J. F.; Zhu, B. R.; Zhao, W. N.; Yang, X. J.; Tang, H. J.

    2017-10-01

    Phase-shifted transformer and DC reactor are usually needed in chopper plasma cutting power supply. Because of high power rate, the loss of magnetic components may reach to several kilowatts, which seriously affects the conversion efficiency. Therefore, it is necessary to research and design low loss magnetic components by means of efficient magnetic materials and optimal design methods. The main task in this paper is to compare the core loss of different magnetic material, to analyze the influence of transformer structure, winding arrangement and wire structure on the characteristics of magnetic component. Then another task is to select suitable magnetic material, structure and wire in order to reduce the loss and volume of magnetic components. Based on the above outcome, the optimization design process of transformer and dc reactor are proposed in chopper plasma cutting power supply with a lot of solutions. These solutions are analyzed and compared before the determination of the optimal solution in order to reduce the volume and power loss of the two magnetic components and improve the conversion efficiency of plasma cutting power supply.

  4. MHD simulation study of compact toroid injection into magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yoshio; Kishimoto, Yasuaki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Hayashi, Takaya [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2000-06-01

    To understand the fuelling process in a fusion device by a compact toroid (CT) plasmoid injection method, we have carried out MHD numerical simulations where a spheromak-like CT (SCT) is injected into a magnetized target plasma region. So far, we revealed that the penetration depth of the SCT plasma becomes shorter than that estimated from the conducting sphere (CS) model, because in the simulation the Lorentz force of the target magnetic field sequentially decelerates the injected SCT while in the CS model only the magnetic pressure force acts as the deceleration mechanism. In this study, we represent the new theoretical model where the injected SCT is decelerated by both the magnetic pressure force and the magnetic tension force (we call it the non-slipping sphere (NS) model) and investigate in detail the deceleration mechanism of the SCT by comparison with simulation results. As a result, it is found that the decrease of the SCT kinetic energy in the simulation coincides with that in the NS model more than in the CS model. It means that not only the magnetic pressure force but also the magnetic tension force acts as the deceleration mechanism of the SCT. Furthermore, it is revealed that magnetic reconnection between the SCT magnetic field and the target magnetic field plays a role to relax the SCT deceleration. (author)

  5. The Plasma Instrument for Magnetic Sounding (PIMS): Enabling Required Plasma Measurements for the Exploration of Europa

    Science.gov (United States)

    Westlake, J. H.; McNutt, R. L., Jr.; Kasper, J. C.; Case, A. W.; Rymer, A. M.; Khurana, K. K.; Stevens, M. L.; Jia, X.; Slavin, J. A.; Paty, C. S.; Smith, H. T.; Kivelson, M.; Saur, J.; Krupp, N.; Roussos, E.; Korth, H.

    2015-12-01

    Europa exists in a complicated plasma environment where the tilt of Jupiter's magnetic field and rapid rotation rate leads to a dynamic interaction with Europa's ionospheric plasma. While understanding this plasma interaction is interesting in its own right, it is crucial for successfully magnetically sounding Europa's subsurface ocean. . In magnetic sounding, currents induced in Europa by the changing Jovian plasma produce a detectable secondary magnetic field that reflects properties of Europa's subsurface ocean such as depth and conductivity. This technique was successfully employed with Galileo observations of Europa to demonstrate that Europa indeed has a subsurface ocean containing more liquid water than Earth's oceans. While these Galileo observations contributed to the renewed interest in Europa, the results raised major questions that remain unanswered, in part due to the large uncertainties in the ice shell thickness, ocean depth, and ocean salinity due to limitations in the observations. Here we present the scientific goals of the Plasma Instrument for Magnetic Sounding (PIMS), one of the 9 instruments selected for the Europa Multiple Flyby Mission. We specifically address how PIMS plasma measurements will transform the accuracy of magnetic sounding of Europa's subsurface oceans. We also present synergistic science with other Europa instrumentation such as the ultraviolet spectrometer, mass spectrometer, and the radar.

  6. Spin dependent transport in magnetically confined plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ohkawa, Tihiro

    2001-05-01

    The transport in tokamaks with internal transport barrier and H-mode is described in terms of emission and absorption of quasi-particles with spin. The process is equivalent of the magnetic reconnection in the wave picture. The transport rate depends on the magnetic helicity profile. The experimental results appear to support the key features of the model. (author)

  7. Anti-screening in magnetically quantized plasmas

    Indian Academy of Sciences (India)

    such media may attract each other. Keywords. Quantized magnetic field .... We begin the study of anisotropic media with non-stationary scalar and vector potentials, ³(Ц Ш) and (Ц Ш), where [8] .... gas the local change of electron density leads to the change of the magnetic field and vice versa [13]. This fact should appear in ...

  8. Instabilities in magnetized inhomogeneous plasmas with the effect of recombination

    Science.gov (United States)

    Jyoti, Joshi, Vishal; Kumar, Tanuj

    2017-03-01

    The Inhomogeneous plasma with positive ions and electrons in which collisions are taking place is considered. To include the modification due to the magnetized plasma, a static magnetic field B0 is considered to be applied in the z-direction and the wave propagation is taken at an angle θ with it in the (X, Z) plane. The ions are assumed to be cold and singly charged. Fluid equations which take into account the recombination effects are formulated for ions and the electrons. Potential is found from Poisson's equation using normal mode analysis (NMA) along with linear approximation, neglecting higher order perturbed terms. From Potential equation, dispersion relation is generated which is solved numerically for obtaining the value of ω using typical plasma parameters. The behavior of growth rate with magnetic field, propagation angle, recombination constant along with different plasma oscillation wavelength to Debye length ratio (λ / λDe) has been studied. Two types of instabilities has been observed. Both the instabilities showing the same behavior with respect to recombination constant, magnetic field and (λ / λDe) plasma oscillation wavelength to Debye wavelength ratio. But they behave opposite to each other with respect to propagation angle (angle between the magnetic field and the propagation vector).

  9. Observation of plasma microwave emission during the injection of supersonic plasma flows into magnetic arch

    Science.gov (United States)

    Viktorov, Mikhail; Mansfeld, Dmitry; Vodopyanov, Alexander; Golubev, Sergey

    2017-10-01

    Understanding of the energy transfer mechanisms from supersonic plasma flow into the thermal energy of plasma, waves and accelerated particles in the environment of planetary bow shocks and interplanetary shocks have been topical for many decades. Almost all mechanisms of energy dissipation in collisionless shock waves end with microscopic processes involving wave-particle interactions. Excitation of plasma waves in electron cyclotron frequency range plays an important role in the dissipation of bulk flow energy across the Earth bow shock. In the present work, the process of plasma deceleration during the injection of supersonic plasma flow across the magnetic field of an arched configuration is experimentally demonstrated. Pulsed plasma microwave emission in the electron cyclotron frequency range is observed. It is shown that the frequency spectrum of plasma emission is determined by the position of the deceleration region in the magnetic field of the magnetic arc and its bandwidth is defined by the magnetic field inhomogeneity in the deceleration region. The observed emission can be related to the cyclotron mechanism of wave generation by non-equilibrium energetic electrons in the dense plasma, especially excitation of electron Bernstein waves. The work was supported by RFBR (Project No. 16-32-60056).

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

    Science.gov (United States)

    Lynn, Alan G; Gilmore, Mark

    2014-11-01

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

  11. Experimental investigation of coaxial-gun-formed plasmas injected into a background transverse magnetic field or plasma

    OpenAIRE

    Zhang, Yue; Hsu, Scott C.; Fisher, Dustin M.; Gilmore, Mark; Lynn, Alan G.

    2017-01-01

    Injection of coaxial-gun-formed magnetized plasmas into a background transverse vacuum magnetic field or into a background magnetized plasma has been studied in the helicon-cathode (HelCat) linear plasma device at the University of New Mexico [M. Gilmore et al., J. Plasma Phys.81, 345810104 (2015)]. Magnetized plasma jet launched into a background transverse magnetic field shows emergent kink stabilization of the jet due to the formation of a sheared flow in the jet above the kink-stabilizati...

  12. Global numerical modeling of magnetized plasma in a linear device

    DEFF Research Database (Denmark)

    Magnussen, Michael Løiten

    Understanding the turbulent transport in the plasma-edge in fusion devices is of utmost importance in order to make precise predictions for future fusion devices. The plasma turbulence observed in linear devices shares many important features with the turbulence observed in the edge of fusion...... devices, and are easier to diagnose due to lower temperatures and a better access to the plasma. In order to gain greater insight into this complex turbulent behavior, numerical simulations of plasma in a linear device are performed in this thesis. Here, a three-dimensional drift-fluid model is derived...... from first principles for a magnetized plasma in a linear device. To account for the fluctuations at the same level as the background plasma, the traditional split between background and fluctuations has not been made. The model is implemented using the BOUT++ framework and is solved numerically...

  13. Three-dimensional global fluid simulations of cylindrical magnetized plasmas

    DEFF Research Database (Denmark)

    Naulin, Volker; Windisch, T.; Grulke, O.

    2008-01-01

    and sinks. The traditional scale separation paradigm is not applied in the simulation model to account for the important evolution of the background profiles due to the dynamics of turbulent fluctuations. Furthermore, the fluid modeling of sheath boundary conditions, which determine the plasma conditions......Plasma dynamics in cylindrical geometry, with many well diagnosed experiments in operation worldwide, is of fundamental interest. These linear machines can provide an unique testing ground for direct and detailed comparisons of numerical simulations of nonlinear plasma dynamics with experiments....... Thus, it is possible to assess the reproductive and predictive capabilities of plasma simulations in unprecedented detail. Here, three-dimensional global fluid simulations of a cylindrical magnetized plasma are presented. This plasma is characterized by the existence of spatially localized sources...

  14. Laboratory Experiments on Propagating Plasma Bubbles into Vacuum, Vacuum Magnetic Field, and Background Plasmas

    Science.gov (United States)

    Lynn, Alan G.; Zhang, Yue; Gilmore, Mark; Hsu, Scott

    2014-10-01

    We discuss the dynamics of plasma ``bubbles'' as they propagate through a variety of background media. These bubbles are formed by a pulsed coaxial gun with an externally applied magnetic field. Bubble parameters are typically ne ~1020 m-3, Te ~ 5 - 10 eV, and Ti ~ 10 - 15 eV. The structure of the bubbles can range from unmagnetized jet-like structures to spheromak-like structures with complex magnetic flux surfaces. Some of the background media the bubbles interact with are vacuum, vacuum with magnetic field, and other magnetized plasmas. These bubbles exhibit different qualitative behavior depending on coaxial gun parameters such as gas species, gun current, and gun bias magnetic field. Their behavior also depends on the parameters of the background they propagate through. Multi-frame fast camera imaging and magnetic probe data are used to characterize the bubble evolution under various conditions.

  15. Performance improvement of magnetized coaxial plasma gun by magnetic circuit on a bias coil

    Science.gov (United States)

    Edo, Takahiro; Matsumoto, Tadafumi; Asai, Tomohiko; Kamino, Yasuhiro; Inomoto, Michiaki; Gota, Hiroshi

    2016-10-01

    A magnetized coaxial plasmoid accelerator has been utilized for compact torus (CT) injection to refuel into fusion reactor core plasma. Recently, CT injection experiments have been conducted on the C-2/C-2U facility at Tri Alpha Energy. In the series of experiments successful refueling, i.e. increased particle inventory of field-reversed configuration (FRC) plasma, has been observed. In order to improve the performance of CT injector and to refuel in the upgraded FRC device, called C-2W, with higher confinement magnetic field, magnetic circuit consisting of magnetic material onto a bias magnetic coil is currently being tested at Nihon University. Numerical work suggests that the optimized bias magnetic field distribution realizes the increased injection velocity because of higher conversion efficiency of Lorenz self force to kinetic energy. Details of the magnetic circuit design as well as results of the test experiment and field calculations will be presented and discussed.

  16. Plasma compression in magnetic reconnection regions in the solar corona

    CERN Document Server

    Provornikova, Elena; Lukin, Vyacheslav S

    2016-01-01

    It has been proposed that particles bouncing between magnetized flows converging in a reconnection region can be accelerated by the first order Fermi mechanism. Analytical considerations of this mechanism have shown that the spectral index of accelerated particles is related to the total plasma compression within the reconnection region similarly to the case of diffusive shock acceleration mechanism. As a first step to investigate the efficiency of Fermi acceleration in reconnection regions in producing hard energy spectra of particles in the solar corona, we explore the degree of plasma compression that can be achieved at reconnection sites. In particular, we aim to determine the conditions for the strong compressions to form. Using a two-dimensional resistive MHD numerical model we consider a set of magnetic field configurations where magnetic reconnection can occur including a Harris current sheet, a force-free current sheet, and two merging flux ropes. Plasma parameters are taken to be characteristic of t...

  17. Self-organizing Knotted Magnetic Structures in Plasma

    CERN Document Server

    Smiet, C B; Thompson, A; Swearngin, J; Dalhuizen, J W; Bouwmeester, D

    2015-01-01

    We perform full-MHD simulations on various initially helical configurations and show that they reconfigure into a state where the magnetic field lines span nested toroidal surfaces. This relaxed configuration is not a Taylor state, as is often assumed for relaxing plasma, but a state where the Lorentz force is balanced by the hydrostatic pressure, which is lowest on the central ring of the nested tori. Furthermore, the structure is characterized by a spatially slowly varying rotational transform, which leads to the formation of a few magnetic islands at rational surfaces. We then obtain analytic expressions that approximate the global structure of the quasi-stable linked and knotted plasma configurations that emerge, using maps from $S^3$ to $S^2$ of which the Hopf fibration is a special case. The knotted plasma configurations have a highly localized magnetic energy density and retain their structure on time scales much longer than the Alfvenic time scale.

  18. On the Magnetic Shield for a Vlasov-Poisson Plasma

    Science.gov (United States)

    Caprino, Silvia; Cavallaro, Guido; Marchioro, Carlo

    2017-12-01

    We study the screening of a bounded body Γ against the effect of a wind of charged particles, by means of a shield produced by a magnetic field which becomes infinite on the border of Γ . The charged wind is modeled by a Vlasov-Poisson plasma, the bounded body by a torus, and the external magnetic field is taken close to the border of Γ . We study two models: a plasma composed by different species with positive or negative charges, and finite total mass of each species, and another made of many species of the same sign, each having infinite mass. We investigate the time evolution of both systems, showing in particular that the plasma particles cannot reach the body. Finally we discuss possible extensions to more general initial data. We show also that when the magnetic lines are straight lines, (that imposes an unbounded body), the previous results can be improved.

  19. Plasma transport in a simulated magnetic-divertor configuration

    Energy Technology Data Exchange (ETDEWEB)

    Strawitch, C. M.

    1981-03-01

    The transport properties of plasma on magnetic field lines that intersect a conducting plate are studied experimentally in the Wisconsin internal ring D.C. machine. The magnetic geometry is intended to simulate certain aspects of plasma phenomena that may take place in a tokamak divertor. It is found by a variety of measurements that the cross field transport is non-ambipolar; this may have important implications in heat loading considerations in tokamak divertors. The undesirable effects of nonambipolar flow make it preferable to be able to eliminate it. However, we find that though the non-ambipolarity may be reduced, it is difficult to eliminate entirely. The plasma flow velocity parallel to the magnetic field is found to be near the ion acoustic velocity in all cases. The experimental density and electron temperature profiles are compared to the solutions to a one dimensional transport model that is commonly used in divertor theory.

  20. The magnetic mirror force in plasma fluid models

    Science.gov (United States)

    Comfort, R. H.

    1988-01-01

    In the past decade, there have been several attempts to include the magnetic mirror force in the equation of motion for a plasma in a fluid formalism. In the process, some confusion has been evident regarding when and how this should be done. This problem has been addressed in the literature, but these treatments appear to have been forgotten or misunderstood. The mathematical arguments are summarized so that the physical consequences are readily perceived. It is shown that for an isotropic plasma fluid, in the direction parallel or anti-parallel to a magnetic field, the forces associated with a diverging magnetic field cancel out. Only for anisotropies in the fluid properties does the diverging field influence the plasma dynamics.

  1. Magnetic Reconnection in a Compressible MHD Plasma

    Science.gov (United States)

    Hesse, Michael; Birn, Joachim; Zenitani, Seiji

    2011-01-01

    Using steady-state resistive MHD, magnetic reconnection is reinvestigated for conditions of high resistivity/low magnetic Reynolds number, when the thickness of the diffusion region is no longer small compared to its length. Implicit expressions for the reconnection rate and other reconnection parameters are derived based on the requirements of mass, momentum, and energy conservation. These expressions are solved via simple iterative procedures. Implications specifically for low Reynolds number/high resistivity are being discussed

  2. Photon splitting in a strongly magnetized, charge-asymmetric plasma

    Directory of Open Access Journals (Sweden)

    Chistyakov M.V.

    2016-01-01

    Full Text Available The process of the photon splitting, γ → γγ, is investigated in the presence of strongly magnetized charge-asymmetric cold plasma. The dispersion properties of photons and the new polarization selection rules are obtained in such plasma. The absorption rate of the leading photon splitting channel are calculated with taking account of the photon dispersion and wave function renormalization. In addition, a comparison of the photon splitting and the Compton scattering processes is performed.

  3. Magnetized plasma flow injection into tokamak and high-beta compact torus plasmas

    Science.gov (United States)

    Matsunaga, Hiroyuki; Komoriya, Yuuki; Tazawa, Hiroyasu; Asai, Tomohiko; Takahashi, Tsutomu; Steinhauer, Loren; Itagaki, Hirotomo; Onchi, Takumi; Hirose, Akira

    2010-11-01

    As an application of a magnetized coaxial plasma gun (MCPG), magnetic helicity injection via injection of a highly elongated compact torus (magnetized plasma flow: MPF) has been conducted on both tokamak and field-reversed configuration (FRC) plasmas. The injected plasmoid has significant amounts of helicity and particle contents and has been proposed as a fueling and a current drive method for various torus systems. In the FRC, MPF is expected to generate partially spherical tokamak like FRC equilibrium by injecting a significant amount of magnetic helicity. As a circumstantial evidence of the modified equilibrium, suppressed rotational instability with toroidal mode number n = 2. MPF injection experiments have also been applied to the STOR-M tokamak as a start-up and current drive method. Differences in the responses of targets especially relation with beta value and the self-organization feature will be studied.

  4. Turbulence and intermittent transport at the boundary of magnetized plasmas

    DEFF Research Database (Denmark)

    Garcia, O.E.; Naulin, V.; Nielsen, A.H.

    2005-01-01

    Numerical fluid simulations of interchange turbulence for geometry and parameters relevant to the boundary region of magnetically confined plasmas are shown to result in intermittent transport qualitatively similar to recent experimental measurements. The two-dimensional simulation domain features...... a forcing region with spatially localized sources of particles and heat outside which losses due to the motion along open magnetic-field lines dominate, corresponding to the edge region and the scrape-off layer, respectively. Turbulent states reveal intermittent eruptions of hot plasma from the edge region...

  5. Vlasov-Fokker-Planck modeling of magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Alexander [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-08-01

    Understanding the magnetic fields that can develop in high-power-laser interactions with solid-density plasma is important because such fields significantly modify both the magnitude and direction of electron heat fluxes. The dynamics of such fields evidently have consequences for inertial fusion energy applications, as the coupling of the laser beams with the walls or pellet and the development of temperature inhomogeneities are critical to the uniformity of the implosion and potentially the success of, for example, the National Ignition Facility. To study these effects, we used the code Impacta, a two-dimensional, fully implicit, Vlasov-Fokker-Planck code with self-consistent magnetic fields and a hydrodynamic ion model, designed for nanosecond time-scale laser-plasma interactions. Heat-flux effects in Ohm’s law under non-local conditions was investigated; physics that is not well captured by standard numerical models but is nevertheless important in fusion-related scenarios. Under such conditions there are numerous interesting physical effects, such as collisional magnetic instabilities, amplification of magnetic fields, re-emergence of non-locality through magnetic convection, and reconnection of magnetic field lines and redistribution of thermal energy. In this project highlights included the first full-scale kinetic simulations of a magnetized hohlraum and the discovery of a new magnetic reconnection mechanism, as well as a completed PhD thesis and the production of a new code for Inertial Fusion research.

  6. Neutral Vlasov kinetic theory of magnetized plasmas

    NARCIS (Netherlands)

    C. Tronci; E. Camporeale (Enrico)

    2014-01-01

    htmlabstractThe low-frequency limit of Maxwell equations is considered in the Maxwell-Vlasov system. This limit produces a neutral Vlasov system that captures essential features of plasma dynamics, while neglecting radiation effects. Euler-Poincar\\'e reduction theory is used to show that the neutral

  7. Neutral Vlasov kinetic theory of magnetized plasmas.

    NARCIS (Netherlands)

    C. Tronci; E. Camporeale (Enrico)

    2015-01-01

    htmlabstractThe low-frequency limit of Maxwell equations is considered in the Maxwell-Vlasov system. This limit produces a neutral Vlasov system that captures essential features of plasma dynamics, while neglecting radiation effects. Euler-Poincar\\'e reduction theory is used to show that the neutral

  8. Laboratory study of collisionless coupling between explosive debris plasma and magnetized ambient plasma

    Science.gov (United States)

    Bondarenko, A. S.; Schaeffer, D. B.; Everson, E. T.; Clark, S. E.; Lee, B. R.; Constantin, C. G.; Vincena, S.; Van Compernolle, B.; Tripathi, S. K. P.; Winske, D.; Niemann, C.

    2017-08-01

    The explosive expansion of a localized plasma cloud into a relatively tenuous, magnetized, ambient plasma characterizes a variety of astrophysical and space phenomena. In these rarified environments, collisionless electromagnetic processes rather than Coulomb collisions typically mediate the transfer of momentum and energy from the expanding "debris" plasma to the surrounding ambient plasma. In an effort to better understand the detailed physics of collisionless coupling mechanisms, compliment in situ measurements of space phenomena, and provide validation of previous computational and theoretical work, the present research jointly utilizes the Large Plasma Device and the Raptor laser facility at the University of California, Los Angeles to study the super-Alfvénic, quasi-perpendicular expansion of laser-produced carbon (C) and hydrogen (H) debris plasma through preformed, magnetized helium (He) ambient plasma via a variety of diagnostics, including emission spectroscopy, wavelength-filtered imaging, and a magnetic flux probe. Doppler shifts detected in a He1+ ion spectral line indicate that the ambient ions initially accelerate transverse to both the debris plasma flow and the background magnetic field. A qualitative analysis in the framework of a "hybrid" plasma model (kinetic ions and inertia-less fluid electrons) demonstrates that the ambient ion trajectories are consistent with the large-scale laminar electric field expected to develop due to the expanding debris. In particular, the transverse ambient ion motion provides direct evidence of Larmor coupling, a collisionless momentum exchange mechanism that has received extensive theoretical and numerical investigation. In order to quantitatively evaluate the observed Doppler shifts, a custom simulation utilizing a detailed model of the laser-produced debris plasma evolution calculates the laminar electric field and computes the initial response of a distribution of ambient test ions. A synthetic Doppler

  9. Explosive X-point collapse in relativistic magnetically dominated plasma

    Science.gov (United States)

    Lyutikov, Maxim; Sironi, Lorenzo; Komissarov, Serguei S.; Porth, Oliver

    2017-12-01

    The extreme properties of the gamma-ray flares in the Crab nebula present a clear challenge to our ideas on the nature of particle acceleration in relativistic astrophysical plasma. It seems highly unlikely that standard mechanisms of stochastic type are at work here and hence the attention of theorists has switched to linear acceleration in magnetic reconnection events. In this series of papers, we attempt to develop a theory of explosive magnetic reconnection in highly magnetized relativistic plasma which can explain the extreme parameters of the Crab flares. In the first paper, we focus on the properties of the X-point collapse. Using analytical and numerical methods (fluid and particle-in-cell simulations) we extend Syrovatsky's classical model of such collapse to the relativistic regime. We find that the collapse can lead to the reconnection rate approaching the speed of light on macroscopic scales. During the collapse, the plasma particles are accelerated by charge-starved electric fields, which can reach (and even exceed) values of the local magnetic field. The explosive stage of reconnection produces non-thermal power-law tails with slopes that depend on the average magnetization . For sufficiently high magnetizations and vanishing guide field, the non-thermal particle spectrum consists of two components: a low-energy population with soft spectrum that dominates the number census; and a high-energy population with hard spectrum that possesses all the properties needed to explain the Crab flares.

  10. Multi-scale magnetic field intermittence in the plasma sheet

    Directory of Open Access Journals (Sweden)

    Z. Vörös

    Full Text Available This paper demonstrates that intermittent magnetic field fluctuations in the plasma sheet exhibit transitory, localized, and multi-scale features. We propose a multifractal-based algorithm, which quantifies intermittence on the basis of the statistical distribution of the "strength of burstiness", estimated within a sliding window. Interesting multi-scale phenomena observed by the Cluster spacecraft include large-scale motion of the current sheet and bursty bulk flow associated turbulence, interpreted as a cross-scale coupling (CSC process.

    Key words. Magnetospheric physics (magnetotail; plasma sheet – Space plasma physics (turbulence

  11. Multi-scale magnetic field intermittence in the plasma sheet

    Directory of Open Access Journals (Sweden)

    Z. Vörös

    2003-09-01

    Full Text Available This paper demonstrates that intermittent magnetic field fluctuations in the plasma sheet exhibit transitory, localized, and multi-scale features. We propose a multifractal-based algorithm, which quantifies intermittence on the basis of the statistical distribution of the "strength of burstiness", estimated within a sliding window. Interesting multi-scale phenomena observed by the Cluster spacecraft include large-scale motion of the current sheet and bursty bulk flow associated turbulence, interpreted as a cross-scale coupling (CSC process.Key words. Magnetospheric physics (magnetotail; plasma sheet – Space plasma physics (turbulence

  12. Investigation of Plasma Exhaust Profile Manipulation Using Magnetic Fields

    Science.gov (United States)

    Shambaugh, Bryan A.

    Electric propulsion systems are known for having a high specific impulse but very low thrust. In the case of a hypersonic, compressible flow, altering the exhaust profile has the potential to alter the exhaust velocity thus changing the total thrust output. In this research, the magnetoplasmadynamic (MPD) effects of applying a toroidal magnetic field to an ionized exhaust plume were investigated to manipulate the exhaust profile of the plasma jet under near vacuum conditions. The project also endeavored to determine the efficacy of permanent magnets as a replacement for electromagnetic systems in rocket propulsion. Tests for this experiment were conducted using the West Virginia University (WVU) Hypersonic Arc Jet Wind Tunnel, in which a series of N52 grade neodymium magnets were placed in different orientations around a steel toroid mounted around the arc jet plume. Four different magnet orientations which produced different magnetic fields around the plume were tested in this experiment: two of the configurations held the magnetic poles aligned with the flow direction with north or south facing the nozzle; two configurations held the magnetic poles in a tangential orientation to the flow with north or south facing in a clockwise direction. All magnets in each of the magnetized cases were positioned equidistant to one another and equidistant to the toroid's central axis. Two additional configurations were run as control tests without any imposed magnetic fields surrounding the plume. Each test was documented using 12 sets of photographs taken from a fixed position with respect to the flow, and the photographic data was analyzed by comparing images of the exhaust plume taken 10, 20, and 30 seconds after the plasma jet was activated. Analysis of the collected images showed that the tangential configurations where the magnets' north poles were oriented clockwise held the most influence in decreasing the size of the exhaust profile across all time steps. In contrast

  13. Electron magnetohydrodynamics of magnetized, inhomogeneous plasmas

    NARCIS (Netherlands)

    Kuvshinov, B. N.; Westerhof, E.; Schep, T. J.; Berning, M.

    1998-01-01

    A modified EMHD model is derived that includes the effects of density perturbations and inhomogeneity in a strong magnetic field. Similar to previous EMHD models, the derived equation takes the form of a flux conservation law for a modified vorticity. The modified vorticity is frozen into the

  14. Dust Effects on a Free Presheaths in Weakly Magnetized Plasmas

    Science.gov (United States)

    Kang, I. J.; Bae, M. K.; Chp, S. G.; Kim, S. Y.; Hong, S. H.; Choi, H. G.; Oh, Y. S.; Oh, H. T.; Park, I. S.; Lho, T.; Chung, K. S.

    2016-10-01

    Dust effects on a diffusion coefficient and a connection length at a free presheath regions have been investigated as a part of experimental simulation of dust interaction with plasmas and plasma edge transport at Divertor Plasma Simulator - 2 (DiPS-2) with the following conditions: plasma density 1 10 × 1012 cm3, electron temperature 1 10 eV and magnetic field 1 kG, where the characteristics of DiPS-2 is the following: 12 V and 280 A for LaB6 heating, 50 - 100 V and 20 - 40 A for plasma discharge. Pulsed laser beams by a 250 mJ Nd:YAG laser were injected to a tungsten target for production of dust particles. Free presheaths were artificially generated by inserting a tungsten perturbing object with diameter = 1.5 cm at the center of plasmas in DiPS-2. Radial plasma profiles were measured by using a fast scanning probe (FSP) system with triple probe (TP) and Mach probe (MP) and a laser induced fluorescence (LIF) system. Dust effects on a diffusion coefficient and a connection length in the presheath region were analysed by comparing the plasma parameter of dusty and pure plasmas.

  15. NATO Advanced Research Workshiop on Superdense QCD Matter and Compact Stars

    CERN Document Server

    Blaschke, David

    2006-01-01

    This volume covers the main topics in the theory of superdense QCD matter and its application to the astrophysics of compact stars in a comprehensive and yet accessible way. The material is presented as a combination of extensive introductory lectures and more topical contributions. The book is centered around the question whether hypothetical new states of dense matter in the compact star interior could give clues to the explanation of puzzling phenomena such as gamma-ray bursts, pulsar glitches, compact star cooling and gravitational waves.

  16. Studies of HED Plasmas with Self-Generated Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Medvedev, Mikhail [Univ. of Kansas, Lawrence, KS (United States)

    2016-02-08

    High-amplitude sub-Larmor-scale electromagnetic turbulence is ubiquitous in high-energy density environments, such as laboratory plasmas produced by high-intensity lasers, e.g., NIF, Omega-EP, Trident, and others, and in astrophysical and space plasmas, e.g., at high-Mach-number collisionless shocks in weakly magnetized plasmas upstream regions of quasi-parallel shocks, sites of magnetic reconnection and others. Studies of plasmas and turbulence in these environments are important for fusion energy sciences and the inertial confinement concept, in particular, as well as to numerous astrophysical systems such as gamma-ray bursts, supernovae blast waves, jets of quasars and active galactic nuclei, shocks in the interplanetary medium, solar flares and many more. Such turbulence can be of various origin and thus have rather different properties, from being purely magnetic (Weibel) turbulence to various types of electromagnetic turbulence (for example, whistler wave turbulence or turbulence produced by filamentation or Weibel-type streaming instability), to purely electrostatic Langmuir turbulence. In this project we use analytical and numerical tools to study the transport, radiative, and magneto-optical properties of plasmas with sub-Larmor-scale turbulence. We discovered the connection of transport/diffusion properties to certain spectral benchmark features of (jitter) radiation produced by the plasma and radiation propagation through it. All regimes, from the relativistic to non-relativistic, were thoroughly investigated and predictions were made for laboratory plasmas and astrophysical plasmas. Thus, all the tasks outlined in the proposal were fully and successfully accomplished.

  17. Injection of a coaxial-gun-produced magnetized plasma into a background helicon plasma

    Science.gov (United States)

    Zhang, Yue; Lynn, Alan; Gilmore, Mark; Hsu, Scott

    2014-10-01

    A compact coaxial plasma gun is employed for experimental investigation of plasma bubble relaxation into a lower density background plasma. Experiments are being conducted in the linear device HelCat at UNM. The gun is powered by a 120-uF ignitron-switched capacitor bank, which is operated in a range of 5 to 10 kV and 100 kA. Multiple diagnostics are employed to investigate the plasma relaxation process. Magnetized argon plasma bubbles with velocities 1.2Cs, densities 1020 m-3 and electron temperature 13eV have been achieved. The background helicon plasma has density 1013 m-3, magnetic field from 200 to 500 Gauss and electron temperature 1eV. Several distinct operational regimes with qualitatively different dynamics are identified by fast CCD camera images. Additionally a B-dot probe array has been employed to measure the spatial toroidal and poloidal magnetic flux evolution to identify plasma bubble configurations. Experimental data and analysis will be presented.

  18. Two Stream Instability in an Inhomogeneous Magnetized Plasma

    Science.gov (United States)

    Jyoti, Jyoti; Malik, Hitendra

    2010-11-01

    A plasma can support several kinds of electrostatic and electromagnetic waves depending upon what the external perturbations are and how the plasma is generated or under what conditions the waves are excited. In the presence of magnetic field, more new kinds of the waves can evolve in the plasma. Moreover, if the free energy is available in the system, then these waves can grow at the cost of this free energy and hence instabilities can take place. In the present investigation, we make an analytical study of a two stream instability in an inhomogeneous magnetized plasma having drifting ions and electrons. We consider a general situation by taking an oblique propagation of the wave from the magnetic field and a constant ionization. Using normal mode analysis, we derive dispersion relation which is solved numerically for the growth rate of the instability. The behavior of growth rate with magnetic field and the propagation angle along with ionization constant has been studied for two different wavelengths of the oscillations. We observe two type of the instabilities out of which one grows at a faster rate and hence is named as fast growing instability. The growth rate of the other slowly growing instability is also examined. We find that the growth rates of both the instabilities attain higher magnitudes at smaller wavelength of the oscillations.

  19. Coulomb collisional relaxation process of ion beams in magnetized plasmas

    OpenAIRE

    Nishimura, Y.

    2010-01-01

    An orbit following code is developed to calculate ion beam trajectories in magnetized plasmas. The equation of motion (the Newton's equation) is solved including the Lorentz force term and Coulomb collisional relaxation term. Furthermore, a new algorithm is introduced by applying perturbation method regarding the collision term as a small term. The reduction of computation time is suggested.

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

    DEFF Research Database (Denmark)

    Bindslev, H.

    1991-01-01

    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...

  1. Electron vortex magnetic holes: A nonlinear coherent plasma structure

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, Christopher T., E-mail: c.t.haynes@qmul.ac.uk; Burgess, David; Sundberg, Torbjorn [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Camporeale, Enrico [Multiscale Dynamics, Centrum Wiskunde and Informatica (CWI), Amsterdam (Netherlands)

    2015-01-15

    We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional particle-in-cell simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to electron mass ratio. These structures, electron vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped electrons in petal-like orbits. The trapped electron population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the plasma, and are stable over at least 100 electron gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform plasma. It is found that (quasi-)stable structures can be formed provided that there is some initial perpendicular temperature anisotropy at the structure location. The properties of these structures (scale size, trapped population, etc.) are able to explain the observed properties of magnetic holes in the terrestrial plasma sheet. EVMHs may also contribute to turbulence properties, such as intermittency, at short scale lengths in other astrophysical plasmas.

  2. Internal magnetic field measurement in tokamak plasmas using a ...

    Indian Academy of Sciences (India)

    There is a growing interest in developing a reliable method for the measurement of the in- ternal magnetic field in high ... This information is essential for understanding confinement, stability and energy balance of the tokamak plasma. .... The instrument measures the difference between the left-hand and right-hand circularly ...

  3. Nonlinear interaction of waves in a hot inhomogeneous magnetized plasma

    Directory of Open Access Journals (Sweden)

    Tara Prasad Khan

    1979-01-01

    inhomogeneous magnetized plasma, is used to determine the threshold value of the electric field and the frequency shift. The results of this paper are also compared with the other known results. It is shown that the findings of this study are in excellent agreement with the results of earlier investigators.

  4. Interaction of a neutral cloud moving through a magnetized plasma

    Science.gov (United States)

    Goertz, C. K.; Lu, G.

    1990-01-01

    Current collection by outgassing probes in motion relative to a magnetized plasma may be significantly affected by plasma processes that cause electron heating and cross field transport. Simulations of a neutral gas cloud moving across a static magnetic field are discussed. The authors treat a low-Beta plasma and use a 2-1/2 D electrostatic code linked with the authors' Plasma and Neutral Interaction Code (PANIC). This study emphasizes the understanding of the interface between the neutral gas cloud and the surrounding plasma where electrons are heated and can diffuse across field lines. When ionization or charge exchange collisions occur a sheath-like structure is formed at the surface of the neutral gas. In that region the crossfield component of the electric field causes the electron to E times B drift with a velocity of the order of the neutral gas velocity times the square root of the ion to electron mass ratio. In addition a diamagnetic drift of the electron occurs due to the number density and temperature inhomogeneity in the front. These drift currents excite the lower-hybrid waves with the wave k-vectors almost perpendicular to the neutral flow and magnetic field again resulting in electron heating. The thermal electron current is significantly enhanced due to this heating.

  5. Kinetic Simulations of Laser Parametric Amplification in Magnetized Plasmas

    Science.gov (United States)

    Jia, Qing; Shi, Yuan; Qin, Hong; Fisch, Nathaniel

    2017-10-01

    Laser pulse compression using magnetized resonance near the upper-hybrid frequency is promising for achieving higher output intensity in regimes previously thought impossible using unmagnetized plasmas. Using one-dimensional particle-in-cell simulations, we verify that, by partially replacing plasma with an external transverse magnetic field of megagauss scale, the output pulse can be intensified by a factor of a few, due to the increased allowable amplification time despite a decreased growth rate. Further improvement is impeded by the generation of an electromagnetic wakefield, to which the amplified pulse loses more energy than it does in the unmagnetized case. This limitation can however be circumvented by the use of a stronger pump. In contrast to unmagnetized compression, the magnetized amplification remains efficient when the pump intensity is well above the wavebreaking threshold, until a higher phase-mixing threshold is exceeded. This surprising resilience to wavebreaking in magnetized plasma is of great benefit for magnetized compression. Work supported by the NNSA Grant No. DE274-FG52-08NA28553 and AFOSR Grant No. FA9550-15-1-0391.

  6. Flexible magnetic design of the MITICA plasma source and accelerator

    Science.gov (United States)

    Chitarin, G.; Marconato, N.; Agostinetti, P.; Serianni, G.; Sonato, P.

    2013-02-01

    MITICA is a negative-Ion-based 1 MeV Neutral Beam Injector. The transverse magnetic field in the plasma source and in the accelerator are crucial for preventing the electrons in the plasma source from entering the accelerator and deflecting the secondary electrons, generated inside the accelerator by stripping reactions with background gas, before they are accelerated at higher energy. The scientific objective of MITICA is essentially the experimental validation of the ITER 1 MeV Neutral Beam injector design and indeed a flexible solution is necessary in order to allow an independent variation of the magnetic field in the plasma source and in the accelerator during the experimental campaign. To this purpose a specific magnetic design has been developed and optimized, essentially based on current-carrying busbars with the possible addition of external coils or magnets. The validated magnetic field configuration will then be replicated in the ITER HNB, using only a current-carrying busbar system. The paper presents the rationale of the various steps of this process and the final design obtained.

  7. Experimental investigation in plasma relaxation by using a compact coaxial magnetized plasma gun in a background plasma

    Science.gov (United States)

    Zhang, Yue; Lynn, Alan; Gilmore, Mark; Hsu, Scott

    2012-10-01

    A compact coaxial plasma gun is employed for experimental studies of plasma relaxation process being conducted in the HELCAT device at UNM. These studies will advance the knowledge of basic plasma physics in the areas of magnetic relaxation and space and astrophysical plasmas, including the evolution of active galactic jets/radio lobes. The gun is powered by a 120pF ignitron-switched capacitor bank which is operated in a range of 5 - 10kV. Multiple diagnostics are employed to investigate plasma relaxation process. Magnetized Argon plasma bubbles with velocities 1.2Cs and densities 10e20 m-3 have been achieved. Different distinct regimes of operation with qualitatively different dynamics are identified by fast CCD camera images, with the parameter lambda determining the operation regime. Additionally, a B-dot probe array is employed to measure the spatial toroidal and poloidal magnetic flux evolution to identify detached plasma bubble configurations. Experimental data and analysis will be presented.

  8. The Plasma Instrument for Magnetic Sounding (PIMS) for the Europa Mission

    Science.gov (United States)

    Westlake, J. H.; McNutt, R. L.; Kasper, J. C.; Case, A. W.; Rymer, A. M.; Stevens, M. L.; Jia, X.; Paty, C.; Khurana, K. K.; Kivelson, M. G.; Slavin, J. A.; Smith, H. T.; Korth, H.; Krupp, N.; Roussous, E.; Saur, J.

    2016-10-01

    We present the Plasma Instrument for Magnetic Sounding (PIMS) selected for the Europa Mission. We specifically address how PIMS plasma measurements will improve the accuracy of magnetic sounding of Europa's subsurface ocean.

  9. Experiments on penetration of a plasma with magnetized electrons across a magnetic field

    Science.gov (United States)

    Cid, R. E.; Cohen, R. H.; Hooper, E. B.; Molvik, A. W.; Porter, G. D.; Ryutov, D. D.

    1998-11-01

    In a number of situations of practical interest, one has to deal with plasma flow past bodies whose size is much greater than the electron gyroradius but much smaller than the ion gyroradius (examples from two very different environments are: spaceraft in the geomagnetic field, and irregularities on the surface of divertor plates). The ions are then repelled from the region inaccessible for electrons by the ambipolar potential, and a shadow with a size much less than the ion gyro-radius is formed. We present a systematic experimental study of plasma penetration into such shadows across the magnetic field lines. The experiments are performed on the Bluebell device situated at LLNL. The flow of an Argon plasma with density up to 10^12 cm-3 and electron temperature 2-3 eV is collimated by holes with diameters from 0.5 to 2 cm made in a thin aluminum disk that intersepts the rest of the plasma. The magnetic field strength is in the range of a few tens of gauss. The plasma density distribution in the gradually expanding plasma jets behind the holes is measured by electrostatic probes. In order to eliminate direct electric contact with the upstream plasma (which is sometimes quite "noisy"), some of the holes are covered with fine metal meshes. We report on the measurements of the cross-field expansion rate of the jets vs. the plasma density, the density of the background gas, and the magnetic field intensity.

  10. Magnetically Induced Transparency in Cold Magnetized Plasma by Spatially Periodic Magneto-static Field

    Science.gov (United States)

    Gad, Raanan; Leopold, John G.; Fisher, Amnon; Ron, Amiram

    2011-10-01

    Electromagnetically Induced Transparency (EIT) is widely investigated. EIT is a resonance absorption line made transparent due to destructive interference between two atomic transitions. A classical analog to quantum EIT is cold magnetized plasma, which resonantly absorbs electromagnetic radiation at the electron cyclotron frequency. Transparency is induced in such plasma by an additional magnetic field, constant in time and varying in space. The proposed physical mechanism is the coupling of longitudinal plasma modulation to the transverse components of the electromagnetic radiation, canceling the forces acting on the plasma electrons. The plasma frequency and the electron cyclotron frequency are the classical analog of the atomic transition frequencies in quantum EIT. Controllable wave propagation parameters such as transmission amplitude and group velocity are some inherent features of MIT. Theoretical study and experimental results will be presented.

  11. Convective cells and blob control in a simple magnetized plasma.

    Science.gov (United States)

    Theiler, C; Furno, I; Loizu, J; Fasoli, A

    2012-02-10

    Blob control by creating convective cells using biased electrodes is demonstrated in simple magnetized toroidal plasmas. A two-dimensional array of electrodes is installed on a metal limiter to obtain different biasing schemes. Detailed two-dimensional measurements across the magnetic field reveal the formation of a convective cell, which shows a high degree of uniformity along the magnetic field. Depending on the biasing scheme, radial and vertical blob velocities can be varied significantly. A high level of cross-field currents limits the achievable potential variations to values well below the applied bias voltage. Furthermore, the strongest potential variations are not induced along the biased flux tube, but at a position shifted in the direction of plasma flows.

  12. Electron vortex magnetic holes: a nonlinear coherent plasma structure

    CERN Document Server

    Haynes, Christopher T; Camporeale, Enrico; Sundberg, Torbjorn

    2014-01-01

    We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional PIC simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to electron mass ratio. These structures, electron vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped electrons in petal-like orbits. The trapped electron population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the plasma, and are stable over at least 100 electron gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform plasma. It is found that (quasi-)stable structures can be formed provided that there is ...

  13. Plasma Equilibrium in a Magnetic Field with Stochastic Regions

    Energy Technology Data Exchange (ETDEWEB)

    J.A. Krommes and Allan H. Reiman

    2009-04-23

    The nature of plasma equilibrium in a magnetic field with stochastic regions is examined. It is shown that the magnetic differential equation that determines the equilibrium Pfirsch-Schluter currents can be cast in a form similar to various nonlinear equations for a turbulent plasma, allowing application of the mathematical methods of statistical turbulence theory. An analytically tractable model, previously studied in the context of resonance-broadening theory, is applied with particular attention paid to the periodicity constraints required in toroidal configurations. It is shown that even a very weak radial diffusion of the magnetic field lines can have a significant effect on the equilibrium in the neighborhood of the rational surfaces, strongly modifying the near-resonant Pfirsch-Schluter currents. Implications for the numerical calculation of 3D equilibria are discussed

  14. Plasma Detachment Mechanisms in Propulsive Magnetic Nozzles

    Science.gov (United States)

    2013-03-07

    this research was provided by the Gobierno de Espa~na (Project AYA-2010-61699). 1E. Ahedo and M. Merino, “Two-dimensional supersonic plasma accelera...T. W. Glover, and G. E. McCaskill, “VASIMR VR vx-200 operation at 200 kw and plume measurements: Future plans and an iss ep test platform,” in 32nd...notwithstanding any copyright notation hereon. Supplementary support has been provided by the Spanish R&D National Plan (Project AYA-2010-61699). 1N

  15. Impact of magnetic perturbation fields on tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Fietz, Sina; Maraschek, Marc; Suttrop, Wolfgang; Zohm, Hartmut [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Classen, Ivo [FOM-Institute DIFFER, Nieuwegein (Netherlands); Collaboration: the ASDEX Upgrade Team

    2015-05-01

    Non-axisymmetric external magnetic perturbation (MP) fields arise in every tokamak e.g. due to not perfectly positioned external coils. Additionally many tokamaks, like ASDEX Upgrade (AUG), are equipped with a set of external coils, which produce a 3D MP field in addition to the equilibrium field. This field is used to either compensate for the intrinsic MP field or to influence MHD instabilities such as Edge Localised Modes (ELMs) or Neoclassical Tearing Modes (NTMs). But these MP fields can also give rise to a more global plasma response. The resonant components can penetrate the plasma and influence the stability of existing NTMs or even lead to their formation via magnetic reconnection. In addition they exert a local torque on the plasma. These effects are less pronounced at high plasma rotation where the resonant field components are screened. The non-resonant components do not influence NTMs directly but slow down the plasma rotation globally via the neoclassical toroidal viscous torque. The island formation caused by the MP field as well as the interaction of pre-existing islands with the MP field at AUG is presented. It is shown that these effects can be modelled using a simple forced reconnection theory. Also the effect of resonant and non-resonant MPs on the plasma rotation at AUG is discussed.

  16. Plasma Wakefield Excitation in a Cold Magnetized Plasma for Particle Acceleration

    Science.gov (United States)

    Karmakar, Mithun; Chakrabarti, Nikhil; Sengupta, Sudip

    2017-10-01

    A numerical study has been done to find a travelling wave solution for a highly relativistic electron beam driven cold magnetized plasma. The presence of magnetic field has an effect to reduce thetransformer ratio (the ratio of energy gain to the drive beam energy) from its unmagnetized value. The effects of beam shape and the non-relativistic ion motion on the nonlinear structures of different dynamical variables are also discussed. The results owe its significance in the laboratory context of particle acceleration or in the study of generation of ultrahigh accelerating charged particle by strong plasma wave in astrophysical situations. Department of Atomic Energy of India and Homi Bhaba National Institute.

  17. Ultra-High Intensity Magnetic Field Generation in Dense Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, Nathaniel J. [Princeton Univ., NJ (United States)

    2014-01-08

    The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereas the efficient generation of electric current in low-­energy-­density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-­energy-­density plasma the ideas for steady-­state current drive developed for low-­energy-­density plasma, or, for that matter, to inventing new methodologies for generating electric current in high-­energy-­density plasma. What we proposed to do was to identify new mechanisms to accomplish current generation, and to assess the operation, physics, and engineering basis of new forms of current drive in regimes appropriate for new fusion concepts.

  18. An integrated approach to the control of magnetically confined plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Albanese, R.; Ambrosino, G.; Ariola, M.; Bagatin, M.; Bellina, F.; Bettini, P.; Borghi, C.A.; Chitarin, G.; Coccorese, E.; Formisano, A.; Fresa, R.; De Magistris, M.; Gnesotto, F.; Guarnieri, M.; Marchiori, G.; Martone, R.; Pironti, A.; Ribani, P.L.; Rubinacci, G.; Stella, A. E-mail: stella@uniud.it; Trevisan, F.; Villone, F

    2001-10-01

    In this paper, a short review of the work done in the framework of a nation-wide research programme on 'Models and Methods for Plasma Control in Magnetically Confined Fusion Experiments' is presented. The broad aim of the overall programme is to develop and propose a new effective and reliable approach to the on-line plasma control for future fusion experiments, starting from the today's theoretical background, validated by experimental evidence from a number of tests performed on existing experiments. The proposed formulation to approach the control problem is a linearized model in terms of suitable state variables and input/output relationships. The basic project has been subdivided into four major areas of investigation: the linearized response plasma model, the three-dimensional electromagnetic model, the identification techniques and finally the plasma control requirements. The most remarkable results, achieved so far in each area above, are presented in the paper.

  19. Effective magnetization of the dust particles in a complex plasma

    Science.gov (United States)

    Kählert, Hanno

    2012-10-01

    The large mass and size of the dust particles in a complex plasma has several advantages, including low characteristic frequencies on the order of a few Hz and the ability to record their motion with video cameras. However, these properties pose major difficulties for achieving strong magnetization. While the light electrons and ions can be magnetized by (superconducting) magnets, magnetizing the heavy dust component is extremely challenging. Instead of further increasing the magnetic field strengths or decreasing the particle size, we use the analogy between the Lorentz force and the Coriolis force experienced by particles in a rotating reference frame to create ``effective magnetic fields'' which is a well-established technique in the field of trapped quantum gases [1]. To induce rotation in a complex plasma, we take advantage of the neutral drag force, which allows to transmit the motion of a rotating neutral gas to the dust particles [2]. The equations of motion in the rotating frame agree with those in a stationary gas except for the additional centrifugal and Coriolis forces [3]. Due to the slow rotation frequencies (˜ Hz) and contrary to the situation in a strong magnetic field, only the properties of the heavy dust particles are notably affected. Experiments with a rotating electrode realize the desired velocity profile for the neutral gas and allow us to verify the efficiency of the concept [3].[4pt] This work was performed in collaboration with J. Carstensen, M. Bonitz, H. L"owen, F. Greiner, and A. Piel.[4pt] [1] A. L. Fetter, Rev. Mod. Phys. 81, 647 (2009)[0pt] [2] J. Carstensen, F. Greiner, L.-J. Hou, H. Maurer, and A. Piel, Phys. Plasmas 16, 013702 (2009)[0pt] [3] H. K"ahlert, J. Carstensen, M. Bonitz, H. L"owen, F. Greiner, and A. Piel, submitted for publication, arXiv:1206.5073

  20. Diffusion of Magnetized Binary Ionic Mixtures at Ultracold Plasma Conditions

    Science.gov (United States)

    Vidal, Keith R.; Baalrud, Scott D.

    2017-10-01

    Ultracold plasma experiments offer an accessible means to test transport theories for strongly coupled systems. Application of an external magnetic field might further increase their utility by inhibiting heating mechanisms of ions and electrons and increasing the temperature at which strong coupling effects are observed. We present results focused on developing and validating a transport theory to describe binary ionic mixtures across a wide range of coupling and magnetization strengths relevant to ultracold plasma experiments. The transport theory is an extension of the Effective Potential Theory (EPT), which has been shown to accurately model correlation effects at these conditions, to include magnetization. We focus on diffusion as it can be measured in ultracold plasma experiments. Using EPT within the framework of the Chapman-Enskog expansion, the parallel and perpendicular self and interdiffusion coefficients for binary ionic mixtures with varying mass ratios are calculated and are compared to molecular dynamics simulations. The theory is found to accurately extend Braginskii-like transport to stronger coupling, but to break down when the magnetization strength becomes large enough that the typical gyroradius is smaller than the interaction scale length. This material is based upon work supported by the Air Force Office of Scientific Research under Award Number FA9550-16-1-0221.

  1. 3-D magnetic reconnection in colliding laser-produced plasmas

    Science.gov (United States)

    Matteucci, Jackson; Fox, Will; Moissard, Clement; Bhattacharjee, Amitava

    2017-10-01

    Recent experiments have demonstrated magnetic reconnection between colliding plasma plumes, where the reconnecting magnetic fields were self-generated in the expanding laser-produced plasmas by the Biermann battery effect. Using fully kinetic 3-D particle in cell simulations, we conduct the first end-to-end simulations of these experiments, including self-consistent magnetic field generation via the Biermann effect through driven magnetic field reconnection. The simulations show rich, temporally and spatially dependent magnetic field reconnection. First, we find fast, vertically-localized ``Biermann-mediated reconnection,'' an inherently 3-D reconnection mechanism where the sign of the Biermann term reverses in the reconnection layer, destroying incoming flux and reconnecting flux downstream. Reconnection then transitions to fast, collisionless reconnection sustained by the non-gyrotropic pressure tensor. To separate out the role 3-D mechanisms, 2-D simulations are initialized based on reconnection-plane cuts of the 3-D simulations. These simulations demonstrate: (1) suppression of Biermann-mediated reconnection in 2-D; (2) similar efficacy of pressure tensor mechanisms in 2-D and 3-D; and (3) plasmoids develop in the reconnection layer in 2-D, where-as they are suppressed in 3-D. Supported by NDSEG Fellowship. This research used resources of the OLCF at ORNL, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.

  2. Generation of Magnetic Fields by a Gravitomagnetic Plasma Battery

    OpenAIRE

    Khanna, Ramon

    1998-01-01

    The generation of magnetic fields by a battery, operating in an ion-electron plasma around a Kerr black hole, is studied in the 3+1 split of the Kerr metric. It is found that the gravitomagnetic contributions to the electron partial pressure are able to drive currents. The strength of the equilibrium magnetic field should be higher than for the classical Biermann battery, which is found to operate in this relativistic context as well, since the gravitomagnetic driving terms can less easily be...

  3. Criterion of sheath formation in magnetized low pressure plasma

    Science.gov (United States)

    Moulick, R.; Adhikari, S.; Goswami, K. S.

    2017-11-01

    A criterion of sheath formation is obtained for magnetized low pressure plasmas. The criterion includes the effect of both collision and the magnetic field. The collision parameter is defined by the ratio of the ionization length to the ion mean free path. The ionization frequency is assumed to be constant. The condition obtained is consistent with the electrostatic case. In the absence of the magnetic field and the collision, it retrieves the Bohm criterion at the sheath edge. For an electrostatic case in the absence of ion neutral collision, the Bohm criterion determines the ion entry speed within the sheath. However, the presence of collision limits the validity of the criterion to a threshold value of the collision parameter. In the magnetized scenario, the validity is found to be dependent on the magnetic field angle besides the collision parameter. Even in a collisionless scenario, the validity is in question depending on the field angle. A critical collision parameter is found for a definite magnetic field strength beyond which there is no more angle dependency on the validity criterion. The effect of the magnetic field on the space charge deposition is highlighted.

  4. New mode of operating a magnetized coaxial plasma gun for injecting magnetic helicity into a spheromak.

    Science.gov (United States)

    Woodruff, S; Hill, D N; Stallard, B W; Bulmer, R; Cohen, B; Holcomb, C T; Hooper, E B; McLean, H S; Moller, J; Wood, R D

    2003-03-07

    By operating a magnetized coaxial plasma gun continuously with just sufficient current to enable plasma ejection, large gun-voltage spikes (approximately 1 kV) are produced, giving the highest sustained voltage approximately 500 V and highest sustained helicity injection rate observed in the Sustained Spheromak Physics Experiment. The spheromak magnetic field increases monotonically with time, exhibiting the lowest fluctuation levels observed during formation of any spheromak (B/B>/=2%). The results suggest an important mechanism for field generation by helicity injection, namely, the merging of helicity-carrying filaments.

  5. Nonlinear electrostatic wave equations for magnetized plasmas - II

    DEFF Research Database (Denmark)

    Dysthe, K. B.; Mjølhus, E.; Pécseli, H. L.

    1985-01-01

    For pt.I see ibid., vol.26, p.443-7 (1984). The problem of extending the high frequency part of the Zakharov equations for nonlinear electrostatic waves to magnetized plasmas, is considered. Weak electromagnetic and thermal effects are retained on an equal footing. Direction dependent (electrosta......For pt.I see ibid., vol.26, p.443-7 (1984). The problem of extending the high frequency part of the Zakharov equations for nonlinear electrostatic waves to magnetized plasmas, is considered. Weak electromagnetic and thermal effects are retained on an equal footing. Direction dependent...... (electrostatic) cut-off implies that various cases must be considered separately, leading to equations with rather different properties. Various equations encountered previously in the literature are recovered as limiting cases....

  6. Growth of nanoparticles in a strongly magnetized plasma

    Science.gov (United States)

    Couedel, Lenaic; Leblanc, Spencer; Hall, Taylor; Konopka, Uwe; Thomas, Edward

    2017-10-01

    This presentation reports on the growth of nanoparticles in the Magnetized Dusty Plasma Experiment (MDPX) device. Two methods of production are investigated: (i) radio-frequency (rf) plasmas are produced in reactive gases (methane and acetylene) mixed with argon or hydrogen and (ii) nanoparticles are grown by sputtering the rf electrode (made of carbon, aluminium, copper, etc). The growth of nanoparticles is followed by monitoring discharge parameters such as the powered electrode self bias and the rf current harmonic content. The dynamics of the growing dust particle cloud is investigated by recording the scattered light of a laser sheath with a high speed video camera. The size distribution and the internal structure of the produced nanoparticles are studied ex-situ using scanning and transmission electron microscopes. The influence of the strength of the magnetic field is explored and the changes in NP growth dynamics and transport are discussed. This work is supported by the US Dept. of Energy, DE-SC0016330.

  7. Magnetic field-aligned electric potentials in nonideal plasma flows

    Science.gov (United States)

    Schindler, K.; Hesse, M.; Birn, J.

    1991-01-01

    The electric field component parallel to the magnetic field arising from plasma flows which violate the frozen-in field condition of ideal magnetohydrodynamics is discussed. The quantity of interest is the potential U = integral E parallel ds where the integral is extended along field lines. It is shown that U can be directly related to magnetic field properties, expressed by Euler potentials, even when time-dependence is included. These results are applicable to earth's magnetosphere, to solar flares, to aligned-rotator models of compact objects, and to galactic rotation. On the basis of order-of-magnitude estimates, these results support the view that parallel electric fields associated with nonideal plasma flows might play an important role in cosmic particle acceleration.

  8. Instabilities, turbulence and transport in a magnetized plasma; Instabilites, turbulence et transport dans un plasma magnetise

    Energy Technology Data Exchange (ETDEWEB)

    Garbet, X

    2001-06-01

    The purpose of this work is to introduce the main processes that occur in a magnetized plasma. During the last 2 decades, the understanding of turbulence has made great progress but analytical formulas and simulations are far to produce reliable predictions. The values of transport coefficients in a tokamak plasma exceed by far those predicted by the theory of collisional transport. This phenomenon is called abnormal transport and might be due to plasma fluctuations. An estimation of turbulent fluxes derived from the levels of fluctuations, is proposed. A flow description of plasma allows the understanding of most micro-instabilities. The ballooning representation deals with instabilities in a toric geometry. 3 factors play an important role to stabilize plasmas: density pinch, magnetic shear and speed shear. The flow model of plasma gives an erroneous value for the stability threshold, this is due to a bad description of the resonant interaction between wave and particle. As for dynamics, flow models can be improved by adding dissipative terms so that the linear response nears the kinetic response. The kinetic approach is more accurate but is complex because of the great number of dimensions involved. (A.C.)

  9. Multi-scale magnetic field intermittence in the plasma sheet

    OpenAIRE

    Vörös, Z.; Baumjohann, W.; Nakamura, R.; Runov, A.; Zhang, T. L.; Volwerk, M.; Eichelberger, H. U.; Balogh, A.; Horbury, T. S.; Glaßmeier, K. -H.; Klecker, B.; Rème, H.

    2004-01-01

    This paper demonstrates that intermittent magnetic field fluctuations in the plasma sheet exhibit transitory, localized, and multi-scale features. We propose a multifractal-based algorithm, which quantifies intermittence on the basis of the statistical distribution of the "strength of burstiness", estimated within a sliding window. Interesting multi-scale phenomena observed by the Cluster spacecraft include large-scale motion of the current sheet and bursty bulk flow ...

  10. Generation of zonal flows in rotating fluids and magnetized plasmas

    DEFF Research Database (Denmark)

    Juul Rasmussen, J.; Garcia, O.E.; Naulin, V.

    2006-01-01

    near the centre with low potential vorticity from the outside, which will imply the formation of a large-scale flow. The experimental results are supported by direct numerical solutions of the quasi-geostrophic vorticity equation in the beta-plane approximation modelling the experimental situation....... The analogy to large-scale flow generation in drift-wave turbulence dynamics in magnetized plasma is briefly discussed....

  11. Currents between tethered electrodes in a magnetized laboratory plasma

    Science.gov (United States)

    Stenzel, R. L.; Urrutia, J. M.

    1989-01-01

    Laboratory experiments on important plasma physics issues of electrodynamic tethers were performed. These included current propagation, formation of wave wings, limits of current collection, nonlinear effects and instabilities, charging phenomena, and characteristics of transmission lines in plasmas. The experiments were conducted in a large afterglow plasma. The current system was established with a small electron-emitting hot cathode tethered to an electron-collecting anode, both movable across the magnetic field and energized by potential difference up to V approx.=100 T(sub e). The total current density in space and time was obtained from complete measurements of the perturbed magnetic field. The fast spacecraft motion was reproduced in the laboratory by moving the tethered electrodes in small increments, applying delayed current pulses, and reconstructing the net field by a linear superposition of locally emitted wavelets. With this technique, the small-amplitude dc current pattern is shown to form whistler wings at each electrode instead of the generally accepted Alfven wings. For the beam electrode, the whistler wing separates from the field-aligned beam which carries no net current. Large amplitude return currents to a stationary anode generate current-driven microinstabilities, parallel electric fields, ion depletions, current disruptions and time-varying electrode charging. At appropriately high potentials and neutral densities, excess neutrals are ionized near the anode. The anode sheath emits high-frequency electron transit-time oscillations at the sheath-plasma resonance. The beam generates Langmuir turbulence, ion sound turbulence, electron heating, space charge fields, and Hall currents. An insulated, perfectly conducting transmission line embedded in the plasma becomes lossy due to excitation of whistler waves and magnetic field diffusion effects. The implications of the laboratory observations on electrodynamic tethers in space are discussed.

  12. Nonlinear Plasma Response to Resonant Magnetic Perturbation in Rutherford Regime

    Science.gov (United States)

    Zhu, Ping; Yan, Xingting; Huang, Wenlong

    2017-10-01

    Recently a common analytic relation for both the locked mode and the nonlinear plasma response in the Rutherford regime has been developed based on the steady-state solution to the coupled dynamic system of magnetic island evolution and torque balance equations. The analytic relation predicts the threshold and the island size for the full penetration of resonant magnetic perturbation (RMP). It also rigorously proves a screening effect of the equilibrium toroidal flow. In this work, we test the theory by solving for the nonlinear plasma response to a single-helicity RMP of a circular-shaped limiter tokamak equilibrium with a constant toroidal flow, using the initial-value, full MHD simulation code NIMROD. Time evolution of the parallel flow or ``slip frequency'' profile and its asymptotic approach to steady state obtained from the NIMROD simulations qualitatively agree with the theory predictions. Further comparisons are carried out for the saturated island size, the threshold for full mode penetration, as well as the screening effects of equilibrium toroidal flow in order to understand the physics of nonlinear plasma response in the Rutherford regime. Supported by National Magnetic Confinement Fusion Science Program of China Grants 2014GB124002 and 2015GB101004, the 100 Talent Program of the Chinese Academy of Sciences, and U.S. Department of Energy Grants DE-FG02-86ER53218 and DE-FC02-08ER54975.

  13. Plasma Acceleration by Rotating Magnetic Field Method using Helicon Source

    Science.gov (United States)

    Furukawa, Takeru; Shimura, Kaichi; Kuwahara, Daisuke; Shinohara, Shunjiro

    2017-10-01

    Electrodeless plasma thrusters are very promising due to no electrode damage, leading to realize further deep space exploration. As one of the important proposals, we have been concentrating on Rotating Magnetic Field (RMF) acceleration method. High-dense plasma (up to 1013 cm-3) can be generated by using a radio frequency (rf) external antenna, and also accelerated by an antenna wound around outside of a discharge tube. In this scheme, thrust increment is achieved by the axial Lorentz force caused by non linear effects. RMF penetration condition into plasma can be more satisfied than our previous experiment, by increasing RMF coil current and decreasing the RMF frequency, causing higher thrust and fuel efficiency. Measurements of AC RMF component s have been conducted to investigate the acceleration mechanism and the field penetration experimentally. This study has been partially supported by Grant-in-Aid for Scientific Research (B: 17H02995) from the Japan Society for the Promotion of Science.

  14. Fast Magnetic Reconnection: Bridging Laboratory and Space Plasma Physics

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Amitava [University New Hampshire- Durham

    2012-02-16

    Recent developments in experimental and theoretical studies of magnetic reconnection hold promise for providing solutions to outstanding problems in laboratory and space plasma physics. Examples include sawtooth crashes in tokamaks, substorms in the Earth’s Magnetosphere, eruptive solar flares, and more recently, fast reconnection in laser-produced high energy density plasmas. In each of these examples, a common and long-standing challenge has been to explain why fast reconnection proceeds rapidly from a relatively quiescent state. In this talk, we demonstrate the advantages of viewing these problems and their solutions from a common perspective. We focus on some recent, surprising discoveries regarding the role of secondary plasmoid instabilities of thin current sheets. Nonlinearly, these instabilities lead to fast reconnection rates that are very weakly dependent on the Lundquist number of the plasma.

  15. Observation of Dust Particle Gyromotion in a Magnetized Dusty Plasma

    Science.gov (United States)

    Compton, C. S.; Amatucci, W. E.; Gatling, G.; Tejero, E.

    2008-11-01

    In dusty plasma research, gyromotion of the dust has been difficult to observe experimentally. Previous experiments by Amatucci et al. have shown gyromotion of a single dust particle [1]. This early work was performed with alumina dust that had a size distribution and non-uniformly shaped particles. In the current experiment, evidence of spherical, monodispersed, dust particles exhibiting gyromotion has been observed. Silica particles 0.97 micrometers in diameter are suspended in a DC glow discharge argon plasma. The experiment is performed in the Naval Research Laboratory's DUsty PLasma EXperiment (DUPLEX Jr.). DUPLEX is a 61-cm tall by 46-cm diameter acrylic chamber allowing full 360 degree optical access for diagnostics. The neutral pressure for the experiment is 230 mTorr with a 275 V bias between the circular electrodes. The electrodes have a separation of 4 cm. A strong magnetic field is created by 2 pairs of neodymium iron boride magnets placed above and below the anode and cathode respectively. The resulting field is 1.4 kG. The dust particles are illuminated with a 25 mW, 672 nm laser. Images are captured using an intensified CCD camera and a consumer digital video cassette recorder. Recent evidence of gyromotion of spherical, monodispersed, dust particles will be presented. [1] Amatucci, W.E., et al., Phys. Plasmas, 11, 2097 (2004)

  16. Electron-Phonon coupling in magnetized semiconductor quantum plasmas

    Science.gov (United States)

    Ghosh, S.; Muley, Apurva

    2017-05-01

    Present paper deals with electron-phonon coupling in piezoelectric n-type magnetized semiconductor plasma under quantum regime. A quantum modified dispersion relation is derived for the evolution of desired electron-phonon coupling in semiconductor plasma using quantum hydrodynamic (QHD) model. The main ingredients of this study are the role of non-dimensional quantum parameter-H and externally applied magneto-static field. The presence of quantum parameter-H includes the contributions of Fermi degenerate pressure and quantum diffraction. It represents the ratio of plasmon energy to Fermi energy of the system, hence is a function of doping concentration n0. An expression for gain coefficient of acoustic wave is obtained in terms of quantum parameter-H and magnetic field under the collision dominated limit. We present the effects of doping in medium and orientation of magnetic field on gain profile of acoustic wave. The results show that the presence of magnetic field and quantum effects through quantum parameter-H effectively modifies the gain per unit length of acoustic wave.

  17. Measurement of magnetic field fluctuations and diamagnetic currents within a laser ablation plasma interacting with an axial magnetic field

    Science.gov (United States)

    Ikeda, S.; Horioka, K.; Okamura, M.

    2017-10-01

    The guiding of laser ablation plasmas with axial magnetic fields has been used for many applications, since its effectiveness has been proven empirically [L. Gray et al., J. Appl. Phys. 53(10), 6628 (1982); J. Wolowski, Laser Part. Beams 20(01), 113 (2002); M. Okamura et al., Rev. Sci. Instrum. 81, 02A510 (2010); Y. Tsui et al., Appl. Phys. Lett. 70(15), 1953 (1997); C. Pagano and J. Lunney, J. Phys. D: Appl. Phys. 43(30), 305202 (2010)]. For more sophisticated and complicated manipulations of the plasma flow, the behavior of the magnetic field during the interaction and the induced diamagnetic current in the plasma plume needs to be clearly understood. To achieve the first milestone for establishing magnetic plasma manipulation, we measured the spatial and temporal fluctuations of the magnetic field caused by the diamagnetic current. We showed that the small fluctuations of the magnetic field can be detected by using a simple magnetic probe. We observed that the field penetrates to the core of the plasma plume. The diamagnetic current estimated from the magnetic field had temporal and spatial distributions which were confirmed to be correlated with the transformation of the plasma plume. Our results show that the measurement by the magnetic probe is an effective method to observe the temporal and spatial distributions of the magnetic field and diamagnetic current. The systematic measurement of the magnetic field variations is a valuable method to establish the magnetic field manipulation of the laser ablation plasma.

  18. Pulsating jet-like structures in magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, V. P. [A. M. Obukhov Institute of Atmospheric Physics RAS, 109017 Moscow (Russian Federation); Pavlov, V. I. [UFR des Mathématiques Pures et Appliquées, Univ. Lille, CNRS FRE 3723 - LML, F-59000 Lille (France)

    2016-08-15

    The formation of pulsating jet-like structures has been studied in the scope of the nonhydrostatic model of a magnetized plasma with horizontally nonuniform density. We discuss two mechanisms which are capable of stopping the gravitational spreading appearing to grace the Rayleigh-Taylor instability and to lead to the formation of stationary or oscillating localized structures. One of them is caused by the Coriolis effect in the rotating frames, and another is connected with the Lorentz effect for magnetized fluids. Magnetized jets/drops with a positive buoyancy must oscillate in transversal size and can manifest themselves as “radio pulsars.” The estimates of their frequencies are made for conditions typical for the neutron star's ocean.

  19. Hall MHD Stability and Turbulence in Magnetically Accelerated Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    H. R. Strauss

    2012-11-27

    The object of the research was to develop theory and carry out simulations of the Z pinch and plasma opening switch (POS), and compare with experimental results. In the case of the Z pinch, there was experimental evidence of ion kinetic energy greatly in excess of the ion thermal energy. It was thought that this was perhaps due to fine scale turbulence. The simulations showed that the ion energy was predominantly laminar, not turbulent. Preliminary studies of a new Z pinch experiment with an axial magnetic field were carried out. The axial magnetic is relevant to magneto - inertial fusion. These studies indicate the axial magnetic field makes the Z pinch more turbulent. Results were also obtained on Hall magnetohydrodynamic instability of the POS.

  20. Superdense matter

    Indian Academy of Sciences (India)

    Abstract. We review recent work on the phase structure of QCD at very high baryon density. We introduce the phenomenon of color superconductivity and discuss the use of weak coupling methods. We study the phase structure as a function of the number of flavors and their masses. We also introduce effective theories that ...

  1. Superdense matter

    Indian Academy of Sciences (India)

    . We introduce the phenomenon of color superconductivity and discuss the use of weak coupling methods. We study the phase structure as a function of the number of flavors and their masses. We also introduce effective theories that describe ...

  2. Human Factors Issues in the Design of Super-Dense Operations Airspace

    Science.gov (United States)

    Smith, P.J.; Spencer, A.L.; Evans, M.; Andre, A.D.; Krozel, J.

    2009-01-01

    A knowledge acquisition study was completed focusing on two questions: 1. What is a concept of operation for the design and use of Super-Dense Operations (SDO) airspace within the next 10 years? 2. What are the human factors issues that need to be addressed in order to enable this concept of operation? To address these questions, a series of structured interviews were conducted with four FAA specialists with significant experience as controllers, traffic managers and airspace designers and with one experienced commercial pilot. The operational concept developed based on the expertise of these individuals has similarities to proposals under the FAA's "Big Airspace" project, making heavy use of advanced Area navigation (RNAV) routes, but goes beyond the current state of that concept by making explicit a number of foundational assumptions, and by proposing a system design to deal with convective weather.

  3. 3-D MHD modeling and stability analysis of jet and spheromak plasmas launched into a magnetized plasma

    Science.gov (United States)

    Fisher, Dustin; Zhang, Yue; Wallace, Ben; Gilmore, Mark; Manchester, Ward; Arge, C. Nick

    2016-10-01

    The Plasma Bubble Expansion Experiment (PBEX) at the University of New Mexico uses a coaxial plasma gun to launch jet and spheromak magnetic plasma configurations into the Helicon-Cathode (HelCat) plasma device. Plasma structures launched from the gun drag frozen-in magnetic flux into the background magnetic field of the chamber providing a rich set of dynamics to study magnetic turbulence, force-free magnetic spheromaks, and shocks. Preliminary modeling is presented using the highly-developed 3-D, MHD, BATS-R-US code developed at the University of Michigan. BATS-R-US employs an adaptive mesh refinement grid that enables the capture and resolution of shock structures and current sheets, and is particularly suited to model the parameter regime under investigation. CCD images and magnetic field data from the experiment suggest the stabilization of an m =1 kink mode trailing a plasma jet launched into a background magnetic field. Results from a linear stability code investigating the effect of shear-flow as a cause of this stabilization from magnetic tension forces on the jet will be presented. Initial analyses of a possible magnetic Rayleigh Taylor instability seen at the interface between launched spheromaks and their entraining background magnetic field will also be presented. Work supported by the Army Research Office Award No. W911NF1510480.

  4. Behaviour of TSI in Magnetized Plasmas for different Plasma Oscillation to Debye Wavelength ratio

    Science.gov (United States)

    Jyoti; Malik, Rakhee

    2017-04-01

    The continuity and the momentum equation which take into account the constant rate of ionization are formulated for ions and the electrons. Using normal mode analysis along with linear approximation, potential is found from Poisson’s equation neglecting higher order perturbed terms. From Potential equation, dispersion relation is generated which is solved numerically for obtaining the value of ω using typical plasma parameters. The behavior of growth rate with magnetic field and the propagation angle along with ionization constant has been studied with different plasma oscillation wavelength to Debye length ratio.

  5. Helicon wave propagation and plasma equilibrium in high-density hydrogen plasma in converging magnetic fields

    Science.gov (United States)

    Caneses Marin, Juan Francisco

    In this thesis, we investigate wave propagation and plasma equilibrium in MAGPIE, a helicon based linear plasma device constructed at the Australian National University, to study plasma-material interactions under divertor-relevant plasma conditions. We show that MAGPIE is capable of producing low temperature (1–8 eV) high density hydrogen plasma (2–3x10. 19 m-3) with 20 kW of RF power when the confining magnetic field is converging. The original research herein described comprises: (1) Characterization of hydrogen plasma in MAGPIE, (2) Analysis of the RF compensation of double Langmuir probes, (3) Excitation, propagation and damping of helicon waves in uniform and non-uniform magnetic fields and (4) Steady-state force balance and equilibrium profiles in MAGPIE. We develop an analytical model of the physics of floating probes to describe and quantify the RF compensation of the DLP technique. Experimental validation for the model is provided. We show that (1) whenever finite sheath effects are important, overestimation of the ion density is proportional to the level of RF rectification and suggest that (2) electron temperature measurements are weakly affected. We develop a uniform plasma full wave code to describe wave propagation in MAGPIE. We show that under typical MAGPIE operating conditions, the helical antenna is not optimized to couple waves in the plasma; instead, the antenna’s azimuthal current rings excites helicon waves which propagate approximately along the whistler wave ray direction, constructively interfere on-axis and lead to the formation of an axial interference pattern. We show that helicon wave attenuation can be explained entirely through electron-ion and electron-neutral collisions. Results from a two-dimensional full wave code reveal that RF power deposition is axially non-uniform with both edge and on-axis components associated with the TG and helicon wave respectively. Finally, force balance analysis in MAGPIE using a two-fluid

  6. Laboratory experiments on plasma jets in a magnetic field using high-power lasers

    Directory of Open Access Journals (Sweden)

    Nishio K.

    2013-11-01

    Full Text Available The experiments to simulate astrophysical jet generation are performed using Gekko XII (GXII HIPER laser system at the Institute of Laser Engineering. In the experiments a fast plasma flow generated by shooting a CH plane (10 μm thickness is observed at the rear side of the plane. By separating the focal spot of the main beams, a non-uniform plasma is generated. The non-uniform plasma flow in an external magnetic field (0.2∼0.3 T perpendicular to the plasma is more collimated than that without the external magnetic field. The plasma β, the ratio between the plasma and magnetic pressure, is ≫ 1, and the magnetic Reynolds number is ∼150 in the collimated plasma. It is considered that the magnetic field is distorted by the plasma flow and enhances the jet collimation.

  7. Radiative decay of keV-mass sterile neutrino in magnetized electron plasma

    Directory of Open Access Journals (Sweden)

    Dobrynina Alexandra

    2017-01-01

    Full Text Available The radiative decay of sterile neutrinos with typical masses of 10 keV is investigated in the presence of an external magnetic field and degenerate electron plasma. Full account is taken of the modified photon dispersion relation relative to vacuum. The limiting cases of relativistic and nonrelativistic plasma are analyzed. The decay rate calculated in a strongly magnetized plasma, as a function of the electron number density, is compared with the unmagnetized plasma limit. It is found that the presence of the strong magnetic field in the electron plasma suppresses the catalyzing influence of the plasma by itself on the sterile-neutrino decay rate.

  8. Analysis on electromagnetic characteristics and military application of non-magnetized discharge plasma

    Science.gov (United States)

    Liu, Yang; Wang, Jiachun; Miao, Lei; Li, Zhigang

    2015-11-01

    Firstly, the dispersion equation of a plane electromagnetic wave in homogeneous and non-magnetized discharge plasma was established. According to the different frequency of electromagnetic wave and plasma parameters, the characteristics were discussed when the plasma interacted with electromagnetic waves. Then the gas discharge approach was put forward according to characteristics of plasma generated by different methods and their advantages and disadvantages. The possibility of using non-magnetized discharge plasma for the military purpose was analyzed. In the end, the principle and characteristics of the application of the non-magnetized discharge plasma were studied in the fields of stealth and protection against strong electromagnetic pulse.

  9. Optimization of the Magnetic Field Structure for Sustained Plasma Gun Helicity Injection for Magnetic Turbulence Studies at the Bryn Mawr Plasma Laboratory

    Science.gov (United States)

    Cartagena-Sanchez, C. A.; Schaffner, D. A.; Johnson, H. K.; Fahim, L. E.

    2017-10-01

    A long-pulsed magnetic coaxial plasma gun is being implemented and characterized at the Bryn Mawr Plasma Laboratory (BMPL). A cold cathode discharged between the cylindrical electrodes generates and launches plasma into a 24cm diameter, 2m long chamber. Three separately pulsed magnetic coils are carefully positioned to generate radial magnetic field between the electrodes at the gun edge in order to provide stuffing field. Magnetic helicity is continuously injected into the flux-conserving vacuum chamber in a process akin to sustained slow-formation of spheromaks. The aim of this source, however, is to supply long pulses of turbulent magnetized plasma for measurement rather than for sustained spheromak production. The work shown here details the optimization of the magnetic field structure for this sustained helicity injection.

  10. Electrodeless plasma acceleration system using rotating magnetic field method

    Directory of Open Access Journals (Sweden)

    T. Furukawa

    2017-11-01

    Full Text Available We have proposed Rotating Magnetic Field (RMF acceleration method as one of electrodeless plasma accelerations. In our experimental scheme, plasma generated by an rf (radio frequency antenna, is accelerated by RMF antennas, which consist of two-pair, opposed, facing coils, and these antennas are outside of a discharge tube. Therefore, there is no wear of electrodes, degrading the propulsion performance. Here, we will introduce our RMF acceleration system developed, including the experimental device, e.g., external antennas, a tapered quartz tube, a vacuum chamber, external magnets, and a pumping system. In addition, we can change RMF operation parameters (RMF applied current IRMF and RMF current phase difference ϕ, focusing on RMF current frequency fRMF by adjusting matching conditions of RMF, and investigate the dependencies on plasma parameters (electron density ne and ion velocity vi; e.g., higher increases of ne and vi (∼360 % and 55 %, respectively than previous experimental results were obtained by decreasing fRMF from 5 MHz to 0.7 MHz, whose RMF penetration condition was better according to Milroy’s expression. Moreover, time-varying component of RMF has been measured directly to survey the penetration condition experimentally.

  11. Electrodeless plasma acceleration system using rotating magnetic field method

    Science.gov (United States)

    Furukawa, T.; Takizawa, K.; Kuwahara, D.; Shinohara, S.

    2017-11-01

    We have proposed Rotating Magnetic Field (RMF) acceleration method as one of electrodeless plasma accelerations. In our experimental scheme, plasma generated by an rf (radio frequency) antenna, is accelerated by RMF antennas, which consist of two-pair, opposed, facing coils, and these antennas are outside of a discharge tube. Therefore, there is no wear of electrodes, degrading the propulsion performance. Here, we will introduce our RMF acceleration system developed, including the experimental device, e.g., external antennas, a tapered quartz tube, a vacuum chamber, external magnets, and a pumping system. In addition, we can change RMF operation parameters (RMF applied current IRMF and RMF current phase difference ϕ, focusing on RMF current frequency fRMF) by adjusting matching conditions of RMF, and investigate the dependencies on plasma parameters (electron density ne and ion velocity vi); e.g., higher increases of ne and vi (˜360 % and 55 %, respectively) than previous experimental results were obtained by decreasing fRMF from 5 MHz to 0.7 MHz, whose RMF penetration condition was better according to Milroy's expression. Moreover, time-varying component of RMF has been measured directly to survey the penetration condition experimentally.

  12. Plasma Beta Dependence of Magnetic Compressibility in Solar Wind Turbulence

    Science.gov (United States)

    Chapman, S. C.; Hnat, B.; Kiyani, K. H.; Sahraoui, F.

    2014-12-01

    The turbulent signature of MHD scales in the near-Earth solar wind are known to be primarily incompressible which manifests itself in magnetic field fluctuation vector components to be aligned primarily perpendicular to the background magnetic field -- so-called "Variance Anisotropy". This, and other facts, have been seen as evidence for a majority Alfvenic turbulence cascade; with a small component (10%) of compressible fluctuations. When one approaches scales on the order of the ion-inertial length and the Larmor radius, this behaviour changes and it is now becoming increasingly evident that the spectral break at these scales is also accompanied by an increase in magnetic compressibility. This has been attributed to a phase change in the physics at these scales -- from fluid to kinetic -- and in particular to the dominant role of the Hall-effect at sub-ion scales. We will be presenting results from the Cluster mission to show how this increase in the compressibility is dependent on the ion plasma beta and what implications this has for the physics at sub-ion scales in the context of prominent theories and models for kinetic plasma turbulence.

  13. Effect of plasma shielding on the fidelity of magnetic probe in a plasma focus environment

    Energy Technology Data Exchange (ETDEWEB)

    Zucker, O.S.

    1978-04-28

    This paper examines the fidelity of a dielectric, encapsulated magnetic probe in the adverse plasma environment encountered in plasma focus experiments. The ionization of the surface of the probe produces a conductive layer that tends to shield it from external magnetic fields. The solution of the wave equation is used to show the allowed regions of conductivity, sigma, and thickness, d, for the ionized layer. The results show that as d approaches the penetration depth, delta = (..omega mu..sigma)/sup /sup 1///sub 2//, severe attenuation and distortion results, rendering the probe useless. When d is much less than delta, we encounter attenuation only, which also may be too severe for use. Finally, an experiment is described, which allows the experimenter to determine the fidelity of the probe.

  14. Nondiffusive suprathermal ion transport in simple magnetized toroidal plasmas

    CERN Document Server

    Gustafson, K; Furno, I; Fasoli, A

    2011-01-01

    We investigate suprathermal ion dynamics in simple magnetized toroidal plasmas in the pres- ence of electrostatic turbulence driven by the ideal interchange instability. Turbulent fields from fluid simulations are used in the non-relativistic equation of ion motion to compute suprathermal tracer ion trajectories. Suprathermal ion dispersion starts with a brief ballistic phase, during which particles do not interact with the plasma, followed by a turbulence interaction phase. In this one simple system, we observe the entire spectrum of suprathermal ion dynamics, from subdiffusion to superdiffusion, depending on beam energy and turbulence amplitude. We estimate the duration of the ballistic phase and identify basic mechanisms during the interaction phase that determine the character of suprathermal ion dispersion upon the beam energy and turbulence fluctuation amplitude.

  15. Accumulative coupling between magnetized tenuous plasma and gravitational waves

    CERN Document Server

    Zhang, Fan

    2016-01-01

    We explicitly compute the plasma wave (PW) induced by a plane gravitational wave (GW) travelling through a region of strongly magnetized plasma, governed by force-free electrodynamics. The PW co-moves with the GW and absorbs its energy to grow over time, creating an essentially force-free counterpart to the inverse-Gertsenshtein effect. The time-averaged Poynting flux of the induced PW is comparable to the vacuum case, but the associated current may offer a more sensitive alternative to photodetection when designing experiments for detecting/constraining high frequency gravitational waves. Aside from the exact solutions, we also offer an analysis of the general properties of the GW to PW conversion process, which should find use when evaluating electromagnetic counterparts to astrophysical gravitational waves, that are generated directly by the latter as a second order phenomenon.

  16. Quark-gluon plasma in strong magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Kalaydzhyan, Tigran

    2013-04-15

    One of the fundamental problems in subatomic physics is the determination of properties of matter at extreme temperatures, densities and electromagnetic fields. The modern ultrarelativistic heavy-ion experiments are able to study such states (the quark-gluon plasma) and indicate that the physics at extreme conditions differs drastically from what is known from the conventional observations. Also the theoretical methods developed mostly within the perturbative framework face various conceptual problems and need to be replaced by a nonperturbative approach. In this thesis we study the physics of the strongly-coupled quark-gluon plasma in external magnetic fields as well as general electromagnetic and topological properties of the QCD and QCD-like systems. We develop and apply various nonperturbative techniques, based on e.g. gauge-gravity correspondence, lattice QCD simulations, relativistic hydrodynamics and condensed-matter-inspired models.

  17. Rotating instability in low-temperature magnetized plasmas.

    Science.gov (United States)

    Boeuf, Jean-Pierre; Chaudhury, Bhaskar

    2013-10-11

    The formation of a rotating instability associated with an ionization front ("rotating spoke") and driven by a cross-field current in a cylindrical magnetized plasma is shown and explained for the first time on the basis of a fully kinetic simulation. The rotating spoke is a strong double layer (electrostatic sheath) moving towards the higher potential region at a velocity close to the critical ionization velocity, a concept proposed by Alfvén in the context of the formation of the solar system. The mechanisms of cross-field electron transport induced by this instability are analyzed.

  18. Nonlinear Langmuir Wave Modulation in Weakly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Dysthe, K. B.; Pécseli, Hans

    1978-01-01

    It is assumed that the magnetic field is only important for the ion motion. Both a fluid and a kinetic description of the ions are considered. It is found that the presence of electrostatic ion cyclotron waves, in addition to the ion acoustic waves also found in unmagnetized plasmas, has a strong...... varying electron heating in the amplitude modulated Langmuir wave. For modulations travelling almost perpendicular to the magnetic field, this effect has a profound influence on a modulational instability...... influence on the modulation stability of plane Langmuir waves. As in the unmagnetized case, kinetic results were found to deviate considerably from those obtained by using a fluid description for the ion dynamics. With particular attention to ionospheric phenomena, the effect is included of the spatially...

  19. Overview and first results of experiments on magnetic reconnection between colliding magnetized plasmas at the National Ignition Facility

    Science.gov (United States)

    Fox, W.; Rosenberg, M.; Schaeffer, D.; Fiksel, G.; Park, H. S.; Kalantar, D.; Bhattacharjee, A.; Huang, Y.-M.; Ji, H.; Matteucci, J.; Gao, L.; Uzdensky, D.; Birkel, A.; Li, C. K.; Hu, S. X.; Shvydky, A.

    2017-10-01

    Expanding laser-produced plasmas naturally self-generate magnetic fields by the Biermann battery effect, and the collision of two plumes can drive magnetic reconnection. The National Ignition Facility at LLNL occupies a unique position for laser-driven magnetic reconnection experiments by simultaneously allowing very large plasma temperature, low plasma resistivity, and large system size, which allows observation of secondary instabilities driven during magnetic reconnection and particle acceleration relevant to astrophysical plasmas. Magnetic reconnection experiments have been conducted on the NIF through the NIF Discovery Science program with the first experimental shots conducted in May 2017. We will present the design of the experimental platform and results from the first experimental day. Magnetic reconnection data is obtained from proton radiography based on a DHe3 backlighter, x-ray self-emission, and a new low-energy particle spectrometer (NIF EPPS-300G) developed by the NIF Facility and Engineering and fielded for the first time on these experiments.

  20. Experiments on helical modes in magnetized thin foil-plasmas

    Science.gov (United States)

    Yager-Elorriaga, David

    2017-10-01

    This paper gives an in-depth experimental study of helical features on magnetized, ultrathin foil-plasmas driven by the 1-MA linear transformer driver at University of Michigan. Three types of cylindrical liner loads were designed to produce: (a) pure magneto-hydrodynamic (MHD) modes (defined as being void of the acceleration-driven magneto-Rayleigh-Taylor instability, MRT) using a non-imploding geometry, (b) pure kink modes using a non-imploding, kink-seeded geometry, and (c) MRT-MHD coupled modes in an unseeded, imploding geometry. For each configuration, we applied relatively small axial magnetic fields of Bz = 0.2-2.0 T (compared to peak azimuthal fields of 30-40 T). The resulting liner-plasmas and instabilities were imaged using 12-frame laser shadowgraphy and visible self-emission on a fast framing camera. The azimuthal mode number was carefully identified with a tracking algorithm of self-emission minima. Our experiments show that the helical structures are a manifestation of discrete eigenmodes. The pitch angle of the helix is simply m / kR , from implosion to explosion, where m, k, and R are the azimuthal mode number, axial wavenumber, and radius of the helical instability. Thus, the pitch angle increases (decreases) during implosion (explosion) as R becomes smaller (larger). We found that there are one, or at most two, discrete helical modes that arise for magnetized liners, with no apparent threshold on the applied Bz for the appearance of helical modes; increasing the axial magnetic field from zero to 0.5 T changes the relative weight between the m = 0 and m = 1 modes. Further increasing the applied axial magnetic fields yield higher m modes. Finally, the seeded kink instability overwhelms the intrinsic instability modes of the plasma. These results are corroborated with our analytic theory on the effects of radial acceleration on the classical sausage, kink, and higher m modes. Work supported by US DOE award DE-SC0012328, Sandia National Laboratories

  1. Particle-in-Cell Simulations of Plasma Interaction with Lunar Crustal Magnetic Anomalies

    Science.gov (United States)

    Poppe, A. R.; Halekas, J. S.; Delory, G. T.; Farrell, W. M.

    2012-03-01

    We present results from a kinetic plasma simulation on the interaction of ambient plasma with lunar crustal magnetic anomalies. We discuss implications of this work for physical phenomena at the Moon, such as lunar swirls and proton implantation.

  2. Relation between magnetic fields and electric currents in plasmas

    Directory of Open Access Journals (Sweden)

    V. M. Vasyliunas

    2005-10-01

    Full Text Available Maxwell's equations allow the magnetic field B to be calculated if the electric current density J is assumed to be completely known as a function of space and time. The charged particles that constitute the current, however, are subject to Newton's laws as well, and J can be changed by forces acting on charged particles. Particularly in plasmas, where the concentration of charged particles is high, the effect of the electromagnetic field calculated from a given J on J itself cannot be ignored. Whereas in ordinary laboratory physics one is accustomed to take J as primary and B as derived from J, it is often asserted that in plasmas B should be viewed as primary and J as derived from B simply as (c/4π∇×B. Here I investigate the relation between ∇×B and J in the same terms and by the same method as previously applied to the MHD relation between the electric field and the plasma bulk flow vmv2001: assume that one but not the other is present initially, and calculate what happens. The result is that, for configurations with spatial scales much larger than the electron inertial length λe, a given ∇×B produces the corresponding J, while a given J does not produce any ∇×B but disappears instead. The reason for this can be understood by noting that ∇×B≠4π/cJ implies a time-varying electric field (displacement current which acts to change both terms (in order to bring them toward equality; the changes in the two terms, however, proceed on different time scales, light travel time for B and electron plasma period for J, and clearly the term changing much more slowly is the one that survives. (By definition, the two time scales are equal at λe. On larger scales, the evolution of B (and hence also of ∇×B is governed by ∇×E, with E determined by plasma dynamics via the generalized Ohm's law; as illustrative simple examples, I discuss the formation of magnetic drift currents in the magnetosphere and of Pedersen and Hall currents in

  3. Stability and transport in magnetic confined plasmas; estabilidad y transporte en plasmas confinados magneticamente

    Energy Technology Data Exchange (ETDEWEB)

    Martinell, J.J.; Herrera, J.J.E.; Morozov, D.K.; Soboleva, T.K.; Vitela, E. [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, A.P. 70-543, 04510 Mexico D.F. (Mexico)

    2000-07-01

    A tokamak is a device with a toroidal geometry that uses magnetic fields to confine a plasma inside a vacuum chamber, in order to produce thermonuclear fusion reactions, releasing large amounts of energy, larger than that employed in operating the device. There are two fundamental problems that have prevented us from achieving this goal: (1) the appearance of different instabilities that are capable of destroying confinement, and (2) the great energy losses resulting from transport to the plasma edge. For several years there has been an enormous effort to study the complex physics behind these two phenomena in order to understand the way they affect the plasma so it is possible to control the unwanted effects. In this Project, different aspects of the Tokamak plasma physics are studied, namely: (a) the transition phenomenon to an improved confinement mode (H mode), (b) the effect impurities have on plasma dynamics in the cooler edge region, (c) the processes leading to a detached divertor regime, which makes energy extraction more efficient, and (d) the burn control of a future nuclear fusion reactor using neural networks. All these are important problems and have to be well understood before the design and construction of a tokamak-based thermonuclear reactor can be undertaken. (Author)

  4. A Laboratory Plasma Experiment for Studying Magnetic Dynamics of Accretion Discs and Jets

    OpenAIRE

    Hsu, S. C.; Bellan, P. M.

    2002-01-01

    This work describes a laboratory plasma experiment and initial results which should give insight into the magnetic dynamics of accretion discs and jets. A high-speed multiple-frame CCD camera reveals images of the formation and helical instability of a collimated plasma, similar to MHD models of disc jets, and also plasma detachment associated with spheromak formation, which may have relevance to disc winds and flares. The plasmas are produced by a planar magnetized coaxial gun. The resulting...

  5. Studies on the transmission of sub-THz waves in magnetized inhomogeneous plasma sheath

    Science.gov (United States)

    Yuan, Kai; Shen, Linfang; Yao, Ming; Deng, Xiaohua; Chen, Zhou; Hong, Lujun

    2018-01-01

    There have been many studies on the sub-terahertz (sub-THz) wave transmission in reentry plasma sheaths. However, only some of them have paid attention to the transmission of sub-THz waves in magnetized plasma sheaths. In this paper, the transmission of sub-THz waves in both unmagnetized and magnetized reentry plasma sheaths was investigated. The impacts of temporal evolution of the plasma sheath on the wave transmission were studied. The transmission of "atmospheric window" frequencies in a magnetized plasma sheath was discussed in detail. According to the study, the power transmission rates (Tp) for the left hand circular (LHC) and the right hand circular modes in the magnetized plasma sheath are obviously higher and lower than those in the unmagnetized plasma sheath, respectively. The Tp of LHC mode increases with both wave frequency and external magnetic field strength. Also, the Tp of LHC mode in both magnetized and unmagnetized plasma sheaths varies with time due to the temporal evolution of the plasma sheath. Moreover, the performance of sub-THz waves in magnetized plasma sheath hints at a new approach to the "blackout" problem. The new approach, which is in the capability of modern technology, is to utilize the communication system operating at 140 GHz with an onboard magnet installed near the antenna.

  6. Magnetic Alfvén‐cyclotron fluctuations of anisotropic nonthermal plasmas

    National Research Council Canada - National Science Library

    Navarro, Roberto E; Muñoz, Víctor; Araneda, Jaime; Viñas, Adolfo F.‐; Moya, Pablo S; Valdivia, Juan A

    2015-01-01

    .... Here we study magnetic Alfvén‐cyclotron fluctuations propagating along a background magnetic field in a plasma composed of thermal and suprathermal protons and electrons via the fluctuation...

  7. ELM suppression in helium plasmas with 3D magnetic fields

    Science.gov (United States)

    Evans, T. E.; Loarte, A.; Orlov, D. M.; Grierson, B. A.; Knölker, M. M.; Lyons, B. C.; Cui, L.; Gohil, P.; Groebner, R. J.; Moyer, R. A.; Nazikian, R.; Osborne, T. H.; Unterberg, E. A.

    2017-08-01

    Experiments in DIII-D, using non-axisymmetric magnetic perturbation fields in high-purity low toroidal rotation, 4He plasmas have resulted in Type-I edge localized mode (ELM) suppression and mitigation. Suppression is obtained in plasmas with zero net input torque near the L-H power threshold using either electron cyclotron resonant heating (ECRH) or balanced co- and counter-I p neutral beam injection (NBI) resulting in conditions equivalent to those expected in ITER’s non-active operating phase. In low-power ECRH H-modes, periods with uncontrolled density and impurity radiation excursions are prevented by applying n  =  3 non-axisymmetric magnetic perturbation fields. ELM suppression results from a reduction and an outward shift of the electron pressure gradient peak compared to that in the high-power ELMing phase. The change in the electron pressure gradient peak is primarily due to a drop in the pedestal temperature rather than the pedestal density.

  8. Dissipation Range of Anisotropic Magnetic Fluctuations in MST plasmas

    Science.gov (United States)

    Titus, James; Almagri, Abdul; Sarff, John; Terry, Paul; Mezonlin, Ephrem

    2017-10-01

    Previous measurements of broadband magnetic fluctuations in the MST reversed field pinch (RFP) revealed a turbulent cascade that is anisotropic with respect to the large-scale (equilibrium) magnetic field and characterized by a power spectrum with exponential falloff at scales larger than expected for classical processes. The cascade is supported by tearing instabilities at the global scale that undergo strong nonlinear coupling, especially through poloidal mode m =1 and m =0 fluctuations. The non-classical dissipation feature may be indicative of the powerful non-collisional ion heating observed in MST plasmas. The previous measurements were done with pickup coils separated in both the toroidal and poloidal directions that allowed a resolution of |k|<1.5 cm-1. We report new measurements with increased spatial resolution, from increasing the number of coil sets (from 2 to 7). This enables an increase in the amount of two-point correlated spectra to be ensemble. Calibration analysis show the new probe measurements agree with the previous probe measurements at the same insertion depth. As the new probe is inserted deeper into the plasma, towards the reversal surface, the exponential component dominates as the power law component goes to zero. This is either due to stronger dissipation or the change in wavenumber resistivity. Work supported by DOE and NSF.

  9. Giant increase in cross-magnetic-field transport rate as an electron-positron plasma cools

    Science.gov (United States)

    Aguirre, F. F.; Ordonez, C. A.

    2017-10-01

    An electron-positron plasma in thermal equilibrium within a uniform magnetic field is studied using a classical trajectory Monte Carlo simulation. The cross-magnetic-field single-particle diffusion coefficient is evaluated as a function of the magnetic field strength and plasma temperature. The transport rate is found to increase by many orders of magnitude as the plasma temperature is lowered, for a magnetic field strength of 1 T. The sharp dependence on temperature is due to electrons and positrons becoming temporarily correlated and drifting across the magnetic field before dissociating.

  10. Avalanches driven by pressure gradients in a magnetized plasma

    Science.gov (United States)

    Van Compernolle, B.; Morales, G. J.

    2017-11-01

    The results are presented for a basic heat transport experiment involving an off-axis heat source in which avalanche events occur. The configuration consists of a long, hollow, cylindrical region of elevated electron temperature embedded in a colder plasma, and far from the device walls [Van Compernolle et al. Phys. Rev. E 91, 031102(R) (2015)]. The avalanche events are identified as sudden rearrangements of the pressure profile following the growth of fluctuations from ambient noise. The intermittent collapses of the plasma pressure profile are associated with unstable drift-Alfvén waves and exhibit both radial and poloidal dynamics. After each collapse, the plasma enters a quiescent phase in which the pressure profile slowly recovers and steepens until a threshold is exceeded, and the process repeats. The use of reference probes as time markers allows for the visualization of the 2D spatio-temporal evolution of the avalanche events. Avalanches are observed only for a limited combination of heating powers and magnetic fields. At higher heating powers, the system transits from the avalanche regime into a regime dominated by sustained drift-Alfvén wave activity. This manuscript focuses on new results that illustrate the individual contributions to the avalanche process from density and temperature gradients in the presence of zero-order, sheared flows.

  11. Simulation of electromagnetic fluctuations in thermal magnetized plasma

    Science.gov (United States)

    López, Rodrigo A.; Yoon, Peter H.

    2017-11-01

    The present paper carries out a particle-in-cell (PIC) simulation in order to validate the recently formulated theory of electromagnetic fluctuations emitted spontaneously in thermal magnetized plasmas (Yoon and López 2017 Phys. Plasmas 24 022117). Numerical plots of theoretically constructed fluctuation spectra and computer simulated fluctuation spectra are compared. While the two results produce an overall favorable agreement for subluminous regime in angular frequency versus wave number space, namely, the domain characterized by phase speed less than the speed of light in vacuo, the present PIC simulation also shows that fluctuation spectra are highly enhanced in the close vicinity of linear eigenmodes, which includes superluminal range that does not satisfy the linear cyclotron wave-particle resonance condition. Since the theory of electromagnetic spontaneous emission, which is based upon linear plasma response and linear wave-particle resonant interactions, strictly forbids emissions in such a regime, the PIC code simulation can only be understood in terms of nonlinear wave-particle interaction. This calls for nonlinear generalization of the spontaneous emission theory.

  12. Tornado-like transport in a magnetized plasma

    Science.gov (United States)

    Poulos, Matthew; van Compernolle, Bart; Morales, George

    2017-10-01

    Recent heat transport experiments conducted in the LAPD device at UCLA in which avalanche events have been previously documented have also lead to the identification of a new tornado-like transport phenomenon. These tornados occur much earlier than the avalanches events, essentially in the interval following the application of the bias voltage that causes the injection of an electron beam from a ring-shaped LaB6 cathode into the afterglow of a cold, magnetized plasma. The tornados exhibit a low-frequency (4 kHz) (much lower than drift-waves), spiraling, global eigenmode whose transient behavior is responsible for significant radial transport well outside the heated region. Detailed experimental observations are compared with a Braginskii transport code that includes the effects of ExB convection induced by the spiraling global eigenmode. New insights are gained into the necessary modifications of classical transport to accurately simulate the spiraling effects and the possible interaction with avalanches. This work is supported by the NSF/DOE partnership in basic plasma science and engineering, Grant Number 1619505, and is performed at the Basic Plasma Science Facility, sponsored jointly by DOE and NSF. Sponsored by DOE/NSF at BaPSF and NSF 1619505.

  13. Interaction of a Relativistic Electron Beam with Magnetized Plasma

    Science.gov (United States)

    Dorfman, Seth; Roytershteyn, Vadim; Cattell, Cynthia; van Compernolle, Bart; Delzanno, Gian Luca

    2017-10-01

    The interaction between relativistic electron beams and a magnetized plasma is a fundamental and practical problem that is relevant to many challenging issues in space physics and astrophysics. For example, it is well known that energetic particles in the Earth's radiation belts pose a danger to communication satellites. Compact electron beam sources may be used on future spacecraft to generate waves that would remove the energetic particles from the radiation belt region. A full understanding of the physics of these waves may also shed light on the mechanism for type II/III solar radio emissions. This talk will discuss experiments proposed to further advance understanding of the physical mechanisms governing beam-plasma interactions. The experiments and supporting simulations will investigate in detail the types of waves (whistler, Langmuir, etc.) produced by high-energy beams, beam stability, and feasibility for future space-based experiments. Experiments will be conducted on the Large Plasma Device (LAPD) at UCLA using a unique variable-energy electron beam recently developed at Los Alamos. We will discuss the proposed experimental setup as well as ongoing feasibility studies conducted using theoretical estimates and kinetic simulations. Supported by NSF.

  14. Helical modulation of the electrostatic plasma potential due to edge magnetic islands induced by resonant magnetic perturbation fields at TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Ciaccio, G., E-mail: giovanni.ciaccio@igi.cnr.it; Spizzo, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Schmitz, O., E-mail: oschmitz@wisc.edu; Frerichs, H. [Department of Engineering Physics, University of Wisconsin–Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States); Abdullaev, S. S. [Institut für Energieforschung-Plasmaphysik, Association EURATOM-FZJ, Jülich (Germany); Evans, T. E. [General Atomics, P.O. Box 85608, San Diego, California 92121 (United States); White, R. B. [Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)

    2015-10-15

    The electrostatic response of the edge plasma to a magnetic island induced by resonant magnetic perturbations to the plasma edge of the circular limiter tokamak TEXTOR is analyzed. Measurements of plasma potential are interpreted by simulations with the Hamiltonian guiding center code ORBIT. We find a strong correlation between the magnetic field topology and the poloidal modulation of the measured plasma potential. The ion and electron drifts yield a predominantly electron driven radial diffusion when approaching the island X-point while ion diffusivities are generally an order of magnitude smaller. This causes a strong radial electric field structure pointing outward from the island O-point. The good agreement found between measured and modeled plasma potential connected to the enhanced radial particle diffusivities supports that a magnetic island in the edge of a tokamak plasma can act as convective cell. We show in detail that the particular, non-ambipolar drifts of electrons and ions in a 3D magnetic topology account for these effects. An analytical model for the plasma potential is implemented in the code ORBIT, and analyses of ion and electron radial diffusion show that both ion- and electron-dominated transport regimes can exist, which are known as ion and electron root solutions in stellarators. This finding and comparison with reversed field pinch studies and stellarator literature suggest that the role of magnetic islands as convective cells and hence as major radial particle transport drivers could be a generic mechanism in 3D plasma boundary layers.

  15. Effects of magnetic drift tangential to magnetic surfaces on neoclassical transport in non-axisymmetric plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Seikichi, E-mail: matsuoka@rist.or.jp [Research Organization for Information Science and Technology, 6F Kimec-Center Build., 1-5-2 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047 (Japan); Satake, Shinsuke; Kanno, Ryutaro [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan); Department of Fusion Science, SOKENDAI (The Graduate University for Advanced Studies), 322-6 Oroshi-cho, Toki 509-5292 (Japan); Sugama, Hideo [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

    2015-07-15

    In evaluating neoclassical transport by radially local simulations, the magnetic drift tangential to a flux surface is usually ignored in order to keep the phase-space volume conservation. In this paper, effect of the tangential magnetic drift on the local neoclassical transport is investigated. To retain the effect of the tangential magnetic drift in the local treatment of neoclassical transport, a new local formulation for the drift kinetic simulation is developed. The compressibility of the phase-space volume caused by the tangential magnetic drift is regarded as a source term for the drift kinetic equation, which is solved by using a two-weight δf Monte Carlo method for non-Hamiltonian system [G. Hu and J. A. Krommes, Phys. Plasmas 1, 863 (1994)]. It is demonstrated that the effect of the drift is negligible for the neoclassical transport in tokamaks. In non-axisymmetric systems, however, the tangential magnetic drift substantially changes the dependence of the neoclassical transport on the radial electric field E{sub r}. The peaked behavior of the neoclassical radial fluxes around E{sub r }={sub  }0 observed in conventional local neoclassical transport simulations is removed by taking the tangential magnetic drift into account.

  16. Behavior of moving plasma in solenoidal magnetic field in a laser ion source.

    Science.gov (United States)

    Ikeda, S; Takahashi, K; Okamura, M; Horioka, K

    2016-02-01

    In a laser ion source, a solenoidal magnetic field is useful to guide the plasma and to control the extracted beam current. However, the behavior of the plasma drifting in the magnetic field has not been well understood. Therefore, to investigate the behavior, we measured the plasma ion current and the total charge within a single pulse in the solenoid by changing the distance from the entrance of the solenoid to a detector. We observed that the decrease of the total charge along the distance became smaller as the magnetic field became larger and then the charge became almost constant with a certain magnetic flux density. The results indicate that the transverse spreading speed of the plasma decreased with increasing the field and the plasma was confined transversely with the magnetic flux density. We found that the reason of the confinement was not magnetization of ions but an influence induced by electrons.

  17. Internal Magnetic Field, Temperature and Density Measurements on Magnetized HED plasmas using Pulsed Polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Roger J. [Univ. of Washington, Seattle, WA (United States)

    2016-10-20

    The goals were to collaborate with the MSX project and make the MSX platform reliable with a performance where pulsed polarimetry would be capable of adding a useful measurement and then to achieve a first measurement using pulsed polarimetry. The MSX platform (outside of laser blow off plasmas adjacent to magnetic fields which are low beta) is the only device that can generate high-beta magnetized collisionless supercritical shocks, and with a large spatial size of ~10 cm. Creating shocks at high Mach numbers and investigating the dynamics of the shocks was the main goal of the project. The MSX shocks scale to astrophysical magnetized shocks and potentially throw light on the generation of highly energetic particles via a mechanism like the Fermi process.

  18. Transient growth of a Vlasov plasma in a weakly inhomogeneous magnetic field

    KAUST Repository

    Ratushnaya, Valeria

    2016-12-17

    We investigate the stability properties of a collisionless Vlasov plasma in a weakly inhomogeneous magnetic field using non-modal stability analysis. This is an important topic in a physics of tokamak plasma rich in various types of instabilities. We consider a thin tokamak plasma in a Maxwellian equilibrium, subjected to a small arbitrary perturbation. Within the framework of kinetic theory, we demonstrate the emergence of short time scale algebraic instabilities evolving in a stable magnetized plasma. We show that the linearized governing operator (Vlasov operator) is non-normal leading to the transient growth of the perturbations on the time scale of several plasma periods that is subsequently followed by Landau damping. We calculate the first-order distribution function and the electric field and study the dependence of the transient growth characteristics on the magnetic field strength and perturbation parameters of the system. We compare our results with uniformly magnetized plasma and field-free Vlasov plasma.

  19. Bondi-Hoyle accretion in an isothermal magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Aaron T.; McKee, Christopher F.; Klein, Richard I. [Department of Astronomy, University of California Berkeley, Berkeley, CA 94720 (United States); Cunningham, Andrew J., E-mail: a.t.lee@berkeley.edu [Lawrence Livermore National Laboratory, P.O. Box 808, L-23, Livermore, CA 94550 (United States)

    2014-03-01

    In regions of star formation, protostars and newborn stars will accrete mass from their natal clouds. These clouds are threaded by magnetic fields with a strength characterized by the plasma β—the ratio of thermal and magnetic pressures. Observations show that molecular clouds have β ≲ 1, so magnetic fields have the potential to play a significant role in the accretion process. We have carried out a numerical study of the effect of large-scale magnetic fields on the rate of accretion onto a uniformly moving point particle from a uniform, non-self-gravitating, isothermal gas. We consider gas moving with sonic Mach numbers of up to M≈45; magnetic fields that are either parallel, perpendicular, or oriented 45° to the flow; and β as low as 0.01. Our simulations utilize adaptive mesh refinement in order to obtain high spatial resolution where it is needed; this also allows the boundaries to be far from the accreting object to avoid unphysical effects arising from boundary conditions. Additionally, we show that our results are independent of our exact prescription for accreting mass in the sink particle. We give simple expressions for the steady-state accretion rate as a function of β and M for the parallel and perpendicular orientations. Using typical molecular cloud values of M∼5 and β ∼ 0.04 from the literature, our fits suggest that a 0.4 M {sub ☉} star accretes ∼4 × 10{sup –9} M {sub ☉} yr{sup –1}, almost a factor of two less than accretion rates predicted by hydrodynamic models. This disparity can grow to orders of magnitude for stronger fields and lower Mach numbers. We also discuss the applicability of these accretion rates versus accretion rates expected from gravitational collapse, and under what conditions a steady state is possible. The reduction in the accretion rate in a magnetized medium leads to an increase in the time required to form stars in competitive accretion models, making such models less efficient than predicted by

  20. Magnetic moment of solar plasma and the Kelvin force: -The driving force of plasma up-flow -

    Science.gov (United States)

    Shibasaki, Kiyoto

    2017-04-01

    Thermal plasma in the solar atmosphere is magnetized (diamagnetic). The magnetic moment does not disappear by collisions because complete gyration is not a necessary condition to have magnetic moment. Magnetized fluid is subjected to Kelvin force in non-uniform magnetic field. Generally, magnetic field strength decreases upwards in the solar atmosphere, hence the Kelvin force is directed upwards along the field. This force is not included in the fluid treatment of MHD. By adding the Kelvin force to the MHD equation of motion, we can expect temperature dependent plasma flows along the field which are reported by many observations. The temperature dependence of the flow speed is explained by temperature dependence of magnetic moment. From the observed parameters, we can infer physical parameters in the solar atmosphere such as scale length of the magnetic field strength and the friction force acting on the flowing plasma. In case of closed magnetic field lines, loop-top concentration of hot plasma is expected which is frequently observed.

  1. Outflow and plasma acceleration in Titan's induced magnetotail: Evidence of magnetic tension forces

    OpenAIRE

    Romanelli, N.; Modolo, Ronan; Dubinin, E.; Berthelier, Jean-Jacques; Bertucci, C.; Wahlund, J. E.; Leblanc, François; Canu, P.; Edberg, Niklas JT; Waite, H.; Kurth, W. S.; Gurnett, D.; Coates, A.; Dougherty, M.

    2014-01-01

    International audience; Cassini plasma wave and particle observations are combined with magnetometer measurements to study Titan's induced magnetic tail. In this study, we report and analyze the plasma acceleration in Titan's induced magnetotail observed in flybys T17, T19 and T40. Radio and Plasma Wave Science (RPWS) observations show regions of cold plasma with electron densities between 0.1 and a few tens of electrons per cubic centimeter. The Cassini Plasma Spectrometer-Ion Mass Spectrome...

  2. Investigation of MHD Instabilities in Jets and Bubbles Using a Compact Coaxial Plasma Gun in a Background Magnetized Plasma

    Science.gov (United States)

    Zhang, Y.; Fisher, D. M.; Wallace, B.; Gilmore, M.; Hsu, S. C.

    2016-10-01

    A compact coaxial plasma gun is employed for experimental investigation of launching plasma into a lower density background magnetized plasma. Experiments are being conducted in the linear device HelCat at UNM. Four distinct operational regimes with qualitatively different dynamics are identified by fast CCD camera images. For regime I plasma jet formation, a global helical magnetic configuration is determined by a B-dot probe array data. Also the m =1 kink instability is observed and verified. Furthermore, when the jet is propagating into background magnetic field, a longer length and lifetime jet is formed. Axial shear flow caused by the background magnetic tension force contributes to the increased stability of the jet body. In regime II, a spheromak-like plasma bubble formation is identified when the gun plasma is injected into vacuum. In contrast, when the bubble propagates into a background magnetic field, the closed magnetic field configuration does not hold anymore and a lateral side, Reilgh-Taylor instability develops. Detailed experimental data and analysis will be presented for these cases.

  3. Characteristics of electromagnetic wave propagation in time-varying magnetized plasma in magnetic window region of reentry blackout mitigation

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2017-02-01

    Full Text Available The “magnetic window” is considered a promising means to eliminate reentry communication blackout. However, the turbulence of plasma sheath results in phase jitter and amplitude turbulence of electromagnetic (EM wave and may influence the eliminating effect. Therefore, the effect of fluctuating property of reentry plasma sheath on EM wave propagation when a magnetic field is used for eliminating blackout is investigated. For this purpose, a time-varying electron density model, which includes both temporal variation and spatial turbulence, is proposed. Hybrid matrix method is also employed to investigate the interaction between time-varying magnetized plasma and EM wave. The EM wave transmission coefficients in time-varying magnetized and unmagnetized plasmas are likewise compared. Simulation results show that amplitude variation and phase jitter also exist on transmitted EM wave, and the turbulent deviation increases as the degree of plasma fluctuates. Meanwhile, the fluctuation of transmitted EM wave attenuates at low-frequency passband and increases at high-frequency passband with the increasing magnetic field. That is, comparing with unmagnetized time-varying plasma, the fluctuation effect can be mitigated by using a magnetic field when the EM wave frequency is at low-frequency passband. However, the mitigating effect can be influenced by the nonuniformity of magnetic field.

  4. Magnetic shield for turbomolecular pump of the Magnetized Plasma Linear Experimental device at Saha Institute of Nuclear Physics.

    Science.gov (United States)

    Biswas, Subir; Chattopadhyay, Monobir; Pal, Rabindranath

    2011-01-01

    The turbo molecular pump of the Magnetized Plasma Linear Experimental device is protected from damage by a magnetic shield. As the pump runs continuously in a magnetic field environment during a plasma physics experiment, it may get damaged owing to eddy current effect. For design and testing of the shield, first we simulate in details various aspects of magnetic shield layouts using a readily available field design code. The performance of the shield made from two half cylinders of soft iron material, is experimentally observed to agree very well with the simulation results.

  5. Superdense Coding with GHZ and Quantum Key Distribution with W in the ZX-calculus

    Directory of Open Access Journals (Sweden)

    Anne Hillebrand

    2012-10-01

    Full Text Available Quantum entanglement is a key resource in many quantum protocols, such as quantum teleportation and quantum cryptography. Yet entanglement makes protocols presented in Dirac notation difficult to verify. This is why Coecke and Duncan have introduced a diagrammatic language for quantum protocols, called the ZX-calculus. This diagrammatic notation is both intuitive and formally rigorous. It is a simple, graphical, high level language that emphasises the composition of systems and naturally captures the essentials of quantum mechanics. In the author's MSc thesis it has been shown for over 25 quantum protocols that the ZX-calculus provides a relatively easy and more intuitive presentation. Moreover, the author embarked on the task to apply categorical quantum mechanics on quantum security; earlier works did not touch anything but Bennett and Brassard's quantum key distribution protocol, BB84. Superdense coding with the Greenberger-Horne-Zeilinger state and quantum key distribution with the W-state are presented in the ZX-calculus in this paper.

  6. Electromagnetic fluctuations in magnetized plasmas. I. The rigorous relativistic kinetic theory

    Energy Technology Data Exchange (ETDEWEB)

    Schlickeiser, R., E-mail: rsch@tp4.rub.de, E-mail: yoonp@umd.edu [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Yoon, P. H., E-mail: rsch@tp4.rub.de, E-mail: yoonp@umd.edu [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of)

    2015-07-15

    Using the system of the Klimontovich and Maxwell equations, the general linear fluctuation theory for magnetized plasmas is developed. General expressions for the electromagnetic fluctuation spectra (electric and magnetic fields) from uncorrelated plasma particles in plasmas with a uniform magnetic field are derived, which are covariantly correct within the theory of special relativity. The general fluctuation spectra hold for plasmas of arbitrary composition, arbitrary momentum dependences of the plasma particle distribution functions, and arbitrary orientations of the wave vector with respect to the uniform magnetic field. Moreover, no restrictions on the values of the real and the imaginary parts of the frequency are made. The derived fluctuation spectra apply to both non-collective fluctuations and collective plasma eigenmodes in magnetized plasmas. In the latter case, kinetic equations for the components of fluctuating electric and magnetic fields in magnetized plasmas are derived that include the effect of spontaneous emission and absorption. In the limiting case of an unmagnetized plasmas, the general fluctuation spectra correctly reduce to the unmagnetized fluctuation spectra derived before.

  7. Two-dimensional electric current effects on a magnetized plasma in contact with a surface

    NARCIS (Netherlands)

    Shumack, A. E.; de Blank, H. J.; Westerhout, J.; van Rooij, G. J.

    2012-01-01

    Significant electric fields both parallel and perpendicular to a magnetic field have been observed and modeled self-consistently in an ITER divertor relevant plasma–wall experiment. Due to magnetization, electric current is found to penetrate the plasma beam outside of the cascaded arc plasma source

  8. A new diagnostic for very high magnetic fields in expanding plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Eliezer, S. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom) ; Mendonca, J.T. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom) ]. E-mail: t.mendonca@rl.ac.uk; Bingham, R. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom) ; Norreys, P. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)

    2005-03-14

    Here we propose a new diagnostic method for the magnetic field inside an expanding plasma, based on the idea of photon acceleration, or photon frequency shift of radiation coming out of the plasma. Examples of application for laser-target interaction in the Peta-Watt regime, and for intense magnetic fields in astrophysical environments are considered.

  9. Pressure and compressibility of a quantum plasma in a magnetic field

    NARCIS (Netherlands)

    Suttorp, L.G.

    1993-01-01

    The equilibrium pressure tensor that occurs in the momentum balance equation for a quantum plasma in a magnetic field is shown to be anisotropic. Its relation to the pressure that follows from thermodynamics is elucidated. A general proof of the compressibility rule for a magnetized quantum plasma

  10. Inertial plasma confinement in a miniature magnetic bottle induced by circularly polarized laser light

    Energy Technology Data Exchange (ETDEWEB)

    Kolka, E. (Plasma Physics Group, SOREQ N.R.C., Yavne (Israel)); Eliezer, S. (Plasma Physics Group, SOREQ N.R.C., Yavne (Israel)); Paiss, Y. (Plasma Physics Group, SOREQ N.R.C., Yavne (Israel))

    1993-08-30

    A megagauss magnetic field generated by circularity polarized laser light is used to get confinement of a plasma contained in a good conductor vessel. In this scheme the inertial confinement is supported by the magnetic forces and the Lawson criterion for a DT plasma might be achieved. (orig.)

  11. Spontaneous emission of electromagnetic fluctuations in Kappa magnetized plasmas

    Science.gov (United States)

    Kim, Sunjung; Schlickeiser, R.; Yoon, P. H.; López, R. A.; Lazar, M.

    2017-12-01

    The present paper formulates the theory of spontaneously emitted electromagnetic (EM) fluctuations in magnetized plasmas containing particles with an anisotropic suprathermal (bi-Kappa) velocity distribution function. The formalism is general applying for an arbitrary wave vector orientation and wave polarization, and for any wave-frequency range. As a specific application, the high-frequency EM fluctuations emitted in the upper-hybrid and multiple harmonic electron cyclotron frequency range are evaluated. The model predictions are confirmed by a comparison with the particle-in-cell simulations. Theoretical analysis and numerical simulations are carried out for an isotropic Kappa but the formalism can be applied for any anisotropic distributions, as well as for lower frequencies ranges which involve the ion response.

  12. Cosmic electrodynamics electrodynamics and magnetic hydrodynamics of cosmic plasmas

    CERN Document Server

    Fleishman, Gregory D

    2013-01-01

    This volume offers a deep and detailed overview of plasma behavior in diverse astrophysical conditions. The presentation is based on a solid science foundation that includes well established physical laws of electromagnetism, hydrodynamics, classical and quantum mechanics and other relevant fields of science. Qualitative ideas and descriptions are followed by quantitative derivations and estimates of key physical quantities, and the results of theories and models are confronted with modern observational data obtained from numerous international science programs. Fundamental astrophysical phenomena, such as charged particle acceleration and magnetic field generation, are presented along with spectacular phenomena, such as stellar winds (including ultra-relativistic pulsar wind), supernova explosions and evolution of its remnants, and solar flares.

  13. MMS Observations of Ion-Scale Magnetic Island in the Magnetosheath Turbulent Plasma

    Science.gov (United States)

    Huang, S. Y.; Sahraoui, F.; Retino, A.; Contel, O. Le; Yuan, Z. G.; Chasapis, A.; Aunai, N.; Breuillard, H.; Deng, X. H.; Zhou, M.; hide

    2016-01-01

    In this letter, first observations of ion-scale magnetic island from the Magnetospheric Multiscale mission in the magnetosheath turbulent plasma are presented. The magnetic island is characterized by bipolar variation of magnetic fields with magnetic field compression, strong core field, density depletion, and strong currents dominated by the parallel component to the local magnetic field. The estimated size of magnetic island is about 8 di, where di is the ion inertial length. Distinct particle behaviors and wave activities inside and at the edges of the magnetic island are observed: parallel electron beam accompanied with electrostatic solitary waves and strong electromagnetic lower hybrid drift waves inside the magnetic island and bidirectional electron beams, whistler waves, weak electromagnetic lower hybrid drift waves, and strong broadband electrostatic noise at the edges of the magnetic island. Our observations demonstrate that highly dynamical, strong wave activities and electron-scale physics occur within ion-scale magnetic islands in the magnetosheath turbulent plasma..

  14. The Ionospheric Bubble Index deduced from magnetic field and plasma observations onboard Swarm

    DEFF Research Database (Denmark)

    Park, Jaeheung; Noja, Max; Stolle, Claudia

    2013-01-01

    In the post-sunset tropical ionospheric F-region plasma density often exhibits depletions, which are usually called equatorial plasma bubbles (EPBs). In this paper we give an overview of the Swarm Level 2 Ionospheric Bubble Index (IBI), which is a standard scientific data of the Swarm mission....... This product called L2-IBI is generated from magnetic field and plasma observations onboard Swarm, and gives information as to whether a Swarm magnetic field observation is affected by EPBs. We validate the performance of the L2-IBI product by using magnetic field and plasma measurements from the CHAMP...

  15. Magnetically driven rotation of thermal plasma jet for non-degradable CF{sub 4} treatment

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sooseok, E-mail: choi@chemenv.titech.ac.jp [Department of Nuclear Engineering, Seoul National University (Korea, Republic of); Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology (Japan); Hong, Sang Hee; Kim, Sungwoo [Department of Nuclear Engineering, Seoul National University (Korea, Republic of); Park, Dong-Wha [Department of Chemical Engineering and Regional Innovation Center for Environmental Technology of Thermal Plasma, Inha University (Korea, Republic of); Watanabe, Takayuki [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology (Japan)

    2012-11-15

    Effects of an externally applied magnetic field on the thermal plasma treatment of non-degradable greenhouse gas were investigated. Tetrafluoromethane (CF{sub 4}) was decomposed as a waste gas, because it is the most stable species among perfluorocompounds and has the highest global warming potential. A permanent magnet equipped on the exit region of a hollow electrode plasma torch produced azimuthal Lorentz force to drive rotational motions of the arc root and the thermal plasma jet. In order to sustain a stable arc discharge, the position of the permanent magnet was determined by numerical analysis on the temperature distribution according to the length of arc column. Forcibly swirling motion of thermal plasma jet was observed in accordance with the strength of applied magnetic field. Increased destruction and removal efficiency of CF{sub 4} was measured in torch operation with the externally applied magnetic field due to the enhanced entrainment of waste gas into the thermal plasma jet.

  16. Laboratory Observation of a Plasma-Flow-State Transition from Diverging to Stretching a Magnetic Nozzle

    Science.gov (United States)

    Takahashi, Kazunori; Ando, Akira

    2017-06-01

    An axial magnetic field induced by a plasma flow in a divergent magnetic nozzle is measured when injecting the plasma flow from a radio frequency (rf) plasma source located upstream of the nozzle. The source is operated with a pulsed rf power of 5 kW, and the high density plasma flow is sustained only for the initial ˜100 μ sec of the discharge. The measurement shows a decrease in the axial magnetic field near the source exit, whereas an increase in the field is detected at the downstream side of the magnetic nozzle. These results demonstrate a spatial transition of the plasma-flow state from diverging to stretching the magnetic nozzle, where the importance of both the Alfvén and ion Mach numbers is shown.

  17. Measurement of magnetic null and field reversal in FRC plasmas using the Hanle effect

    Science.gov (United States)

    Gupta, Deepak; Nordsieck, Kenneth; Ignace, Richard; Kinley, John; Nations, Marcel; TAE, Tri Alpha Energy, Team

    2017-10-01

    In FRC plasmas, knowledge of the magnetic null location is required for understanding and comparison with theory and modeling. More fundamentally, one would first like to affirm the presence of field reversal. Conventional methods like internal magnetic probes, Zeeman effect, MSE, etc. have limitations, either due to their perturbative nature or the relatively low internal magnetic fields of FRCs. Here, use of the Hanle effect to measure the magnetic null and field reversal in an FRC is presented. The measurements utilize polarization of resonance radiation from the ions in the plasma using either external illumination or self-illumination. The mechanism of the Hanle effect, conditions of its use as a plasma diagnostic, and various schemes for measurements in an FRC will be presented, along with results from initial tests using a DC plasma discharge with varying magnetic field. The diagnostic design for the C-2W FRC plasma experiment will be discussed.

  18. Influence of external magnetic field on laser breakdown plasma in aqueous Au nanoparticles colloidal solutions

    CERN Document Server

    Serkov, A A; Simakin, A V; Kuzmin, P G; Mikhailova, G N; Antonova, L Kh; Troitskii, A V; Kuzmin, G P; Shafeev, G A

    2016-01-01

    Influence of permanent magnetic field up to 7.5 T on plasma emission and laser-assisted Au nanoparticles fragmentation in water is experimentally studied. It is found that presence of magnetic field causes the breakdown plasma emission to start earlier regarding to laser pulse. Field presence also accelerates the fragmentation of nanoparticles down to a few nanometers. Dependence of Au NPs fragmentation rate in water on magnetic field intensity is investigated. The results are discussed on the basis of laser-induced plasma interaction with magnetic field.

  19. Pursuing the plasma dynamo and MRI in the laboratory: Hydrodynamic studies of unmagnetized plasmas at large magnetic Reynolds number

    Science.gov (United States)

    Weisberg, David B.

    A new method for studying flow-driven MHD instabilities in the laboratory has been developed, using a highly conductive, low viscosity, spherical plasma. The confinement, heating, and stirring of this unmagnetized plasma has been demonstrated experimentally, laying the foundations for the laboratory studies of a diverse collection of astrophysically-relevant instabilities. Specifically, plasma flows conducive to studies of the dynamo effect and the magnetorotational instability (MRI) are measured using a wide array of plasma diagnostics, and compare favorably to hydrodynamic numerical models. The Madison plasma dynamo experiment (MPDX) uses a cylindrically symmetric spherical boundary ring cusp geometry built from strong permanent magnets to confine a large (R=1.5 m), warm (Te torques using current drawn from emissive LaB6 cathodes located at the magnetized plasma edge, which also ionize and heat the plasma via sizable discharge current injection. Combination Langmuir/Mach probes measure maximum velocities of 6 km/s and 3 km/s in helium and argon plasmas, respectively, and ion viscosity is shown to be an efficient mechanism for transporting momentum from the magnetized edge into the unmagnetized core. Momentum loss to neutral charge-exchange collisions serves as the main source of drag on the bulk plasma velocity, and ionization fraction (He ˜ 0.6, Ar ˜ 0.95) is shown to be a limiting factor in momentum penetration. High Alfven Mach number flows have also been generated by drawing current across a global axial magnetic field, resulting in a velocity geometry conducive to MRI experiments. The experiment has achieved magnetic Reynolds numbers of Rm < 250 and fluid Reynolds numbers of Re < 200 (significantly higher than previous flow experiments in cusp-confined plasmas), setting the stage for future research of flow-driven MHD instabilities.

  20. Relation between magnetic fields and electric currents in plasmas

    Directory of Open Access Journals (Sweden)

    V. M. Vasyliunas

    2005-10-01

    Full Text Available Maxwell's equations allow the magnetic field B to be calculated if the electric current density J is assumed to be completely known as a function of space and time. The charged particles that constitute the current, however, are subject to Newton's laws as well, and J can be changed by forces acting on charged particles. Particularly in plasmas, where the concentration of charged particles is high, the effect of the electromagnetic field calculated from a given J on J itself cannot be ignored. Whereas in ordinary laboratory physics one is accustomed to take J as primary and B as derived from J, it is often asserted that in plasmas B should be viewed as primary and J as derived from B simply as (c/4π∇×B. Here I investigate the relation between ∇×B and J in the same terms and by the same method as previously applied to the MHD relation between the electric field and the plasma bulk flow vmv2001: assume that one but not the other is present initially, and calculate what happens. The result is that, for configurations with spatial scales much larger than the electron inertial length λe, a given ∇×B produces the corresponding J, while a given J does not produce any ∇×B but disappears instead. The reason for this can be understood by noting that ∇×B≠4π/cJ implies a time-varying electric field (displacement current which acts to change both terms (in order to bring them toward equality; the changes in the two terms, however, proceed on different time scales, light travel time for B and electron plasma period for J, and clearly the term changing much more slowly is the one that survives. (By definition, the two time scales are equal at λe. On larger scales, the evolution of B (and hence also of ∇×B is governed by

  1. Spatial structure of summertime ionospheric plasma near magnetic noon

    Directory of Open Access Journals (Sweden)

    R. W. Sims

    2005-01-01

    Full Text Available Results are presented from a multi-instrument study of the spatial distribution of the summertime, polar ionospheric electron density under conditions of relatively stable IMF Bz<0. The EISCAT Svalbard radar revealed a region of enhanced densities near magnetic noon that, when comparing radar scans from different local times, appeared to be spatially confined in longitude. This was identified as the tongue-of-ionisation (TOI that comprised photoionisation of sub-auroral origin that is drawn poleward into the polar cap by the anti-sunward flow of the high-latitude convection. The TOI was bounded in longitude by high-latitude troughs; the pre-noon trough on the morning side with a minimum near 78° N and the post-noon trough on the afternoon side with a minimum at 80° N. Complementary measurements by radio tomography, the SuperDARN radars, and a DMSP satellite, together with comparisons with earlier modelling work, provided supporting evidence for the interpretation of the density structuring, and highlighted the role of plasma convection in the formation of summertime plasma distribution. Soft particle precipitation played only a secondary role in the modulation of the large summertime densities entering the polar cap.

  2. Transmission Grating Imaging Spectrometer for Magnetically Confined Fusion Plasmas

    Science.gov (United States)

    Blagojevic, B.; Stutman, D.; Vero, R.; Finkenthal, M.; Moos, H. W.

    2001-10-01

    The Johns Hopkins Plasma Spectroscopy Group is developing a transmission grating (TG) based imaging spectrometer for the soft and ultrasoft X-ray (USXR) ranges. The spectrometer will be integrated into a multi-purpose impurity diagnostic package for Magnetically Confined Fusion experiments, which will provide time and space resolved information about radiation losses, Zeff profiles and particle transport. The package will also include 2-D filtered USXR diode arrays and atomic physics and impurity transport computational capability. The spectrometer has a very simple layout, consisting of two collimating and space resolving slits, a TG and a 2-D imaging detector. As detector we are developing phosphor (P45) coated fiber optic plates with CCD and intensified CCD image readout. The performance of a test 5000 l/mm, 2:1 bar to open area ratio TG has been evaluated in the laboratory using a K-alpha Manson source and the emission from a Penning Discharge. The incident and diffracted photon flux was recorded in the 10-300 Å range with a gas flow proportional counter. The measurements show that spectral resolution and efficiency agree well with the predicted values. A device optimized for spectral resolution and higher order suppression will be tested on the CDX-U and NSTX tokamak at Princeton Plasma Physics Laboratory. Work supported by DoE grant No. DE-FG02-86ER52314ATDoE

  3. Plasma dynamics and heating/acceleration during driven magnetic reconnection

    Science.gov (United States)

    Cheng, C. Z.; Ono, Y.; Inoue, S.; Horiuchi, R.

    2016-12-01

    Highlights of the plasma dynamics and energization during anti-parallel driven magnetic reconnection are presented. The MHD condition breaks down in the entire reconnection layer (the reconnection current layer, the separatrix region and the whole downstream), and the plasma dynamics is also significantly different from the results of the Hall-MHD model. In particular, we explain (1) how electron and ion dynamics decouple and how the charge separation and electrostatic electric field are produced in the reconnection current layer and outflow exhaust and around the separatrix regions, (2) how electrons and ions gain energy in the reconnection current layer, (3) why the electron outflow velocity in the reconnection exhaust reaches super-Alfvenic speed and the ion outflow velocity reaches Alfvenic speed and how the parallel electric field is produced around the separatrix region, (4) how electrons are accelerated by the parallel electric field to form electron beam around the separatrix region and flat-top distribution in the immediate upstream region of the current layer, and (5) how ions gain energy when they move across the separatrix region into the downstream. We will compare the simulation results with observations of MMS and Geotail satellites.

  4. Progress toward the creation of magnetically confined pair plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, Haruhiko [Max-Planck-Institut fuer Plasmaphysik (Germany); The University of Tokyo (Japan); Hergenhahn, Uwe; Paschkowski, Norbert; Stanja, Juliane; Stenson, Eve V. [Max-Planck-Institut fuer Plasmaphysik (Germany); Niemann, Holger; Sunn Pedersen, Thomas [Max-Planck-Institut fuer Plasmaphysik (Germany); Ernst-Moritz-Arndt-Universitaet Greifswald (Germany); Stoneking, Matthew R. [Max-Planck-Institut fuer Plasmaphysik (Germany); Lawrence University (United States); Hugenschmidt, Christoph; Piochacz, Christian; Vohburger, Sebastian [Technische Universitaet Muenchen (Germany); Schweikhard, Lutz [Ernst-Moritz-Arndt-Universitaet Greifswald (Germany); Danielson, James R.; Surko, Clifford M. [University of California, San Diego (United States)

    2016-07-01

    The PAX (Positron Accumulation eXperiment) and APEX (A Positron Electron eXperiment) projects aim to experimentally study the unique wave propagation and stability properties of pair plasmas. We plan to accumulate a large number of positrons in a multicell-type trap system (PAX) and to confine them with electrons in APEX, a levitated dipole or stellarator configuration, operated at the NEPOMUC facility, the world's most intense positron source. In this contribution, we report on recent results from PAX and APEX. We have conducted electron experiments with a 2.3 T Penning-Malmberg trap; confinement for more than 1 hour and observation of a collective mode were demonstrated. At NEPOMUC, we have characterized the positron beam for a wide energy range. In a prototype permanent-magnet dipole trap, efficient (38%) injection of the remoderated 5 eV positron beam was realized using E x B drifts. Based on these results, design studies on the confinement of pair-plasmas in a levitated dipole trap are ongoing.

  5. Recent Progress on the magnetic turbulence experiment at the Bryn Mawr Plasma Laboratory

    Science.gov (United States)

    Schaffner, D. A.; Cartagena-Sanchez, C. A.; Johnson, H. K.; Fahim, L. E.; Fiedler-Kawaguchi, C.; Douglas-Mann, E.

    2017-10-01

    Recent progress is reported on the construction, implementation and testing of the magnetic turbulence experiment at the Bryn Mawr Plasma Laboratory (BMPL). The experiment at the BMPL consists of an ( 300 μs) long coaxial plasma gun discharge that injects magnetic helicity into a flux-conserving chamber in a process akin to sustained slow-formation of spheromaks. A 24cm by 2m cylindrical chamber has been constructed with a high density axial port array to enable detailed simultaneous spatial measurements of magnetic and plasma fluctuations. Careful positioning of the magnetic structure produced by the three separately pulsed coils (one internal, two external) are preformed to optimize for continuous injection of turbulent magnetized plasma. High frequency calibration of magnetic probes is also underway using a power amplifier.

  6. Mechanism and scaling for convection of isolated structures in nonuniformly magnetized plasmas

    DEFF Research Database (Denmark)

    Garcia, O.E.; Bian, N.H.; Naulin, V.

    2005-01-01

    Large-scale radial advection of isolated structures in nonuniformly magnetized plasmas is investigated. The underlying mechanism considered is due to the nonlinear evolution of interchange motions, without any presumption of plasma sheaths. Theoretical arguments supported by numerical simulations...... of the structures, compares favorably with recent experimental measurements of radially propagating blob structures in the scrape-off layer of magnetically confined plasmas. (C) 2005 American Institute of Physics....

  7. Plasma confinement time in trimix-M galatea multipole magnetic trap

    Science.gov (United States)

    Bishaev, A. M.; Bugrova, A. I.; Kozintseva, M. V.; Lipatov, A. S.; Sigov, A. S.; Kharchevnikov, V. K.

    2010-05-01

    The confinement time of hydrogen plasma trapped in a Trimix-M magnetic multipole galatea was studied in a range of plasma densities (1 × 1016 - 6 × 1018 m-3) and ion energies (˜100-300 eV). It is established that (i) the confinement time increases with decreasing plasma density in the trap and (ii) as the barrier magnetic field is increased, the plasma confinement time grows faster than according to a linear law. The obtained results are indicative of a collisional character of plasma diffusion through the barrier field in the trap.

  8. Recent advances in fueling magnetically confined plasmas with pellets

    Energy Technology Data Exchange (ETDEWEB)

    Baylor, L.R.; Combs, S.K.; Fisher, P.W.; Gouge, M.J.; Jernigan, T.C.

    2000-07-01

    Pellet injection has been used for many years in a number of magnetic confinement fusion experiments to provide plasma fueling and density profile control. A pellet fueling system for a reactor-sized device will need to supply hydrogenic fuel as deeply into the plasma as possible to replace the deuterium-tritium ions consumed and to provide a density gradient for plasma particle (especially helium ash) flow to the edge. Development of injection systems that can provide deep fueling with sufficient throughput to provide these features remains a high priority in the fusion technology program. Several tokamak devices, including DIII-D, ASDEX-Upgrade, and JET, have recently employed pellet injection from the high magnetic field side (inner wall). Injection from the high field side (HFS) yields improved fuel penetration and fueling efficiency over the usual simpler method of low-field-side injection from the outside midplane. There is a resulting improvement in fueling efficiency and fuel deposition. The improvement is believed to be due to a {del}B drift and curvature-induced drift of the pellet ablatant in the major radius direction. Curved guide tubes must be employed to inject from the inner wall in all current devices requiring slow to moderate pellet speeds to obtain intact pellets. Alternative injection schemes that take advantage of the HFS injection while allowing for high-speed pellet injection are possible using a vertical injection geometry. The technology to produce cryogenic pellets of hydrogenic isotopes has matured to the level of reliable pellet injection devices that produce and accelerate intact pellets at high repetition rates. New technology enhancements to pneumatic guns have been developed for the production of slower-speed pellets that can survive the curved guide tubes required for HFS injection. Centrifugal accelerators have also been operated at the low velocities required for HFS fueling. The understanding of pellet mechanical properties

  9. STRUCTURE OF PROMINENCE LEGS: PLASMA AND MAGNETIC FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Levens, P. J.; Labrosse, N. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Schmieder, B. [Observatoire de Paris, Meudon, F-92195 (France); Ariste, A. López, E-mail: p.levens.1@research.gla.ac.uk [Institut de Recherche en Astrophysique et Planétologie, Toulouse (France)

    2016-02-10

    We investigate the properties of a “solar tornado” observed on 2014 July 15, and aim to link the behavior of the plasma to the internal magnetic field structure of the associated prominence. We made multi-wavelength observations with high spatial resolution and high cadence using SDO/AIA, the Interface Region Imaging Spectrograph (IRIS) spectrograph, and the Hinode/Solar Optical Telescope (SOT) instrument. Along with spectropolarimetry provided by the Télescope Héliographique pour l’Etude du Magnétisme et des Instabilités Solaires telescope we have coverage of both optically thick emission lines and magnetic field information. AIA reveals that the two legs of the prominence are strongly absorbing structures which look like they are rotating, or oscillating in the plane of the sky. The two prominence legs, which are both very bright in Ca ii (SOT), are not visible in the IRIS Mg ii slit-jaw images. This is explained by the large optical thickness of the structures in Mg ii, which leads to reversed profiles, and hence to lower integrated intensities at these locations than in the surroundings. Using lines formed at temperatures lower than 1 MK, we measure relatively low Doppler shifts on the order of ±10 km s{sup −1} in the tornado-like structure. Between the two legs we see loops in Mg ii, with material flowing from one leg to the other, as well as counterstreaming. It is difficult to interpret our data as showing two rotating, vertical structures that are unrelated to the loops. This kind of “tornado” scenario does not fit with our observations. The magnetic field in the two legs of the prominence is found to be preferentially horizontal.

  10. Properties of highly electronegative plasmas produced in a multipolar magnetic-confined device with a transversal magnetic filter

    DEFF Research Database (Denmark)

    Draghici, Mihai; Stamate, Eugen

    2010-01-01

    electrodes on plasma parameters, the formation of the negative ion sheath and etching rates by positive and negative ions have been investigated for different experimental conditions. When the electron temperature was reduced below 1 eV the density ratio of negative ion to electron exceeded 100 even for very...... low amounts of SF6 gas. The plasma potential drift could be controlled by proper wall conditioning. A large electrode biased positively had no effect on plasma potential for density ratios of negative ions to electrons larger than 50. For similar electronegativities or higher a negative ion sheath......Highly electronegative plasmas were produced in Ar/SF6 gas mixtures in a dc discharge with multipolar magnetic confinement and transversal magnetic filter. Langmuir probe and mass spectrometry were used for plasma diagnostics. Plasma potential drift, the influence of small or large area biased...

  11. Experimental investigation of plasma sheaths in magnetic mirror and cusp configurations

    Science.gov (United States)

    Jiang, Zhengqi; Wei, Zi-an; Ma, J. X.

    2017-11-01

    Sheath structures near a metal plate in a magnetized plasma were experimentally investigated in magnetic mirror and cusp configurations. Plasma parameters and the sheath potential distributions were probed by a planar and an emissive probe, respectively. The measured sheath profiles in the mirror configuration show that the sheath thickness first decreases and then increases when the magnetic strength is raised. A magnetic flux-tube model was used to explain this result. In the cusp configuration, the measured sheath thickness decreases with the increase of the coil current creating the magnetic cusp. However, when normalized by the electron Debye length, the dependence of the sheath thickness on the coil current is reversed.

  12. Fundamental Statistical Descriptions of Plasma Turbulence in Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    John A. Krommes

    2001-02-16

    A pedagogical review of the historical development and current status (as of early 2000) of systematic statistical theories of plasma turbulence is undertaken. Emphasis is on conceptual foundations and methodology, not practical applications. Particular attention is paid to equations and formalism appropriate to strongly magnetized, fully ionized plasmas. Extensive reference to the literature on neutral-fluid turbulence is made, but the unique properties and problems of plasmas are emphasized throughout. Discussions are given of quasilinear theory, weak-turbulence theory, resonance-broadening theory, and the clump algorithm. Those are developed independently, then shown to be special cases of the direct-interaction approximation (DIA), which provides a central focus for the article. Various methods of renormalized perturbation theory are described, then unified with the aid of the generating-functional formalism of Martin, Siggia, and Rose. A general expression for the renormalized dielectric function is deduced and discussed in detail. Modern approaches such as decimation and PDF methods are described. Derivations of DIA-based Markovian closures are discussed. The eddy-damped quasinormal Markovian closure is shown to be nonrealizable in the presence of waves, and a new realizable Markovian closure is presented. The test-field model and a realizable modification thereof are also summarized. Numerical solutions of various closures for some plasma-physics paradigms are reviewed. The variational approach to bounds on transport is developed. Miscellaneous topics include Onsager symmetries for turbulence, the interpretation of entropy balances for both kinetic and fluid descriptions, self-organized criticality, statistical interactions between disparate scales, and the roles of both mean and random shear. Appendices are provided on Fourier transform conventions, dimensional and scaling analysis, the derivations of nonlinear gyrokinetic and gyrofluid equations

  13. Effect of ECRH and resonant magnetic fields on formation of magnetic islands in the T-10 tokamak plasma

    Science.gov (United States)

    Shestakov, E. A.; Savrukhin, P. V.

    2017-10-01

    Experiments in the T-10 tokamak demonstrated possibility of controlling the plasma current during disruption instability using the electron cyclotron resonance heating (ECRH) and the controlled operation of the ohmic current-holding system. Quasistable plasma discharge with repeating sawtooth oscillations can be restored after energy quench using auxiliary ECRH power when PEC / POH > 2–5. The external magnetic field generation system consisted of eight saddle coils that were arranged symmetrically relative to the equatorial plane of the torus outside of the vacuum vessel of the T-10 tokamak to study the possible resonant magnetic field effects on the rotation frequency of magnetic islands. The saddle coils power supply system is based on four thyristor converters with a total power of 300 kW. The power supply control system is based on Siemens S7 controllers. As shown by preliminary experiments, the interaction efficiency of external magnetic fields with plasma depends on the plasma magnetic configuration. Optimal conditions for slowing the rotation of magnetic islands were determined. Additionally, the direction of the error magnetic field in the T-10 tokamak was determined, and the threshold value of the external magnetic field was determined.

  14. One-step isolation of plasma membrane proteins using magnetic beads with immobilized concanavalin A

    DEFF Research Database (Denmark)

    Lee, Yu-Chen; Block, Gregory; Chen, Huiwen

    2008-01-01

    We have developed a simple method for isolating and purifying plasma membrane proteins from various cell types. This one-step affinity-chromatography method uses the property of the lectin concanavalin A (ConA) and the technique of magnetic bead separation to obtain highly purified plasma membrane...... proteins from crude membrane preparations or cell lines. ConA is immobilized onto magnetic beads by binding biotinylated ConA to streptavidin magnetic beads. When these ConA magnetic beads were used to enrich plasma membranes from a crude membrane preparation, this procedure resulted in 3.7-fold enrichment...... of plasma membrane marker 5'-nucleotidase activity with 70% recovery of the activity in the crude membrane fraction of rat liver. In agreement with the results of 5'-nucleotidase activity, immunoblotting with antibodies specific for a rat liver plasma membrane protein, CEACAM1, indicated that CEACAM1...

  15. Nonlinear electrostatic periodic waves and solitons in an inhomogeneous magnetized dusty plasma

    Science.gov (United States)

    Mahmood, S.; Haque, Q.

    2017-09-01

    Low frequency nonlinear electrostatic cnoidal and solitary waves are investigated in an inhomogeneous magnetized dusty plasma in the presence of shear flow. The Sagdeev potential approach is used to find the nonlinear wave solution. It is found that nonlinear electrostatic potential rarefactive (dip) structures are formed for cnoidal waves and solitons in a magnetized inhomogeneous dusty plasma instead of compressive (hump) nonlinear electrostatic wave structures formed in an inhomogeneous magnetized electron-ion plasma. The amplitude of the nonlinear electrostatic potential structure is found to be increased in the case of decreasing shear flow parameter values in comparison with the case of increasing shear flow parameter values. The D'Angelo instability in an inhomogeneous magnetized dusty plasma in the presence of shear flow is also discussed. The numerical plots are also presented for illustrations which are applicable to space dusty plasma regions containing shear flows. The Hamiltonian function of such a dynamical planar system is also discussed for its phase portrait analysis.

  16. Persistence of magnetic field driven by relativistic electrons in a plasma

    CERN Document Server

    Flacco, A; Lifschitz, A; Sylla, F; Kahaly, S; Veltcheva, M; Silva, L O; Malka, V

    2015-01-01

    The onset and evolution of magnetic fields in laboratory and astrophysical plasmas is determined by several mechanisms, including instabilities, dynamo effects and ultra-high energy particle flows through gas, plasma and interstellar-media. These processes are relevant over a wide range of conditions, from cosmic ray acceleration and gamma ray bursts to nuclear fusion in stars. The disparate temporal and spatial scales where each operates can be reconciled by scaling parameters that enable to recreate astrophysical conditions in the laboratory. Here we unveil a new mechanism by which the flow of ultra-energetic particles can strongly magnetize the boundary between the plasma and the non-ionized gas to magnetic fields up to 10-100 Tesla (micro Tesla in astrophysical conditions). The physics is observed from the first time-resolved large scale magnetic field measurements obtained in a laser wakefield accelerator. Particle-in-cell simulations capturing the global plasma and field dynamics over the full plasma le...

  17. Development of a new experimental device for long-duration magnetic reconnection in weakly ionized plasma

    Science.gov (United States)

    Yanai, Ryoma; Kaminou, Yasuhiro; Nishida, Kento; Inomoto, Michiaki

    2016-10-01

    Magnetic reconnection is a universal phenomenon which determines global structure and energy conversion in magnetized plasmas. Many experimental studies have been carried out to explore the physics of magnetic reconnection in fully ionized condition. However, it is predicted that the behavior of magnetic reconnection in weakly ionized plasmas such as solar chromosphere plasma will show different behavior such as ambipolar diffusion caused by interaction with neutral particles. In this research, we are developing a new experimental device to uncover the importance of ambipolar diffusion during magnetic reconnection in weakly ionized plasmas. We employ an inverter-driven rotating magnetic fields technique, which is used for generating steady azimuthal plasma current, to establish long-duration ( 1 ms) anti-parallel reconnection with magnetic field of 5 mT in weakly ionized plasma. We will present development status and initial results from the new experimental setup. This work was supported by JSPS A3 Foresight Program ``Innovative Tokamak Plasma Startup and Current Drive in Spherical Torus'', Giant-in Aid for Scientific Research (KAKENHI) 15H05750, 15K14279, 26287143 and the NIFS Collaboration Research program (NIFS14KNWP004).

  18. Irregular-regular mode oscillations inside plasma bubble and its fractal analysis in glow discharge magnetized plasma

    Science.gov (United States)

    Megalingam, Mariammal; Hari Prakash, N.; Solomon, Infant; Sarma, Arun; Sarma, Bornali

    2017-04-01

    Experimental evidence of different kinds of oscillations in floating potential fluctuations of glow discharge magnetized plasma is being reported. A spherical gridded cage is inserted into the ambient plasma volume for creating plasma bubbles. Plasma is produced between a spherical mesh grid and chamber. The spherical mesh grid of 80% optical transparency is connected to the positive terminal of power supply and considered as anode. Two Langmuir probes are kept in the ambient plasma to measure the floating potential fluctuations in different positions within the system, viz., inside and outside the spherical mesh grid. At certain conditions of discharge voltage (Vd) and magnetic field, irregular to regular mode appears, and it shows chronological changes with respect to magnetic field. Further various nonlinear analyses such as Recurrence Plot, Hurst exponent, and Lyapunov exponent have been carried out to investigate the dynamics of oscillation at a range of discharge voltages and external magnetic fields. Determinism, entropy, and Lmax are important measures of Recurrence Quantification Analysis which indicate an irregular to regular transition in the dynamics of the fluctuations. Furthermore, behavior of the plasma oscillation is characterized by the technique called multifractal detrended fluctuation analysis to explore the nature of the fluctuations. It reveals that it has a multifractal nature and behaves as a long range correlated process.

  19. Rayleigh-Taylor-instability evolution in colliding-plasma-jet experiments with magnetic and viscous stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Colin Stuart [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States); Univ. of Washington, Seattle, WA (United States)

    2015-01-15

    The Rayleigh-Taylor instability causes mixing in plasmas throughout the universe, from micron-scale plasmas in inertial confinement fusion implosions to parsec-scale supernova remnants. The evolution of this interchange instability in a plasma is influenced by the presence of viscosity and magnetic fields, both of which have the potential to stabilize short-wavelength modes. Very few experimental observations of Rayleigh-Taylor growth in plasmas with stabilizing mechanisms are reported in the literature, and those that are reported are in sub-millimeter scale plasmas that are difficult to diagnose. Experimental observations in well-characterized plasmas are important for validation of computational models used to make design predictions for inertial confinement fusion efforts. This dissertation presents observations of instability growth during the interaction between a high Mach-number, initially un-magnetized plasma jet and a stagnated, magnetized plasma. A multi-frame fast camera captures Rayleigh-Taylor-instability growth while interferometry, spectroscopy, photodiode, and magnetic probe diagnostics are employed to estimate plasma parameters in the vicinity of the collision. As the instability grows, an evolution to longer mode wavelength is observed. Comparisons of experimental data with idealized magnetohydrodynamic simulations including a physical viscosity model suggest that the observed instability evolution is consistent with both magnetic and viscous stabilization. These data provide the opportunity to benchmark computational models used in astrophysics and fusion research.

  20. Fractional diffusion models of transport in magnetically confined plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Castillo-Negrete, D. del; Carreras, B. A.; Lynch, V. E.

    2005-07-01

    Experimental and theoretical evidence suggests that transport in magnetically confined fusion plasmas deviates from the standard diffusion paradigm. Some examples include the confinement time scaling in L-mode plasmas, rapid pulse propagation phenomena, and inward transport in off-axis fueling experiments. The limitations of the diffusion paradigm can be traced back to the restrictive assumptions in which it is based. In particular, Fick's law, one of the cornerstones of diffusive transport, assumes that the fluxes only depend on local quantities, i. e. the spatial gradient of the field (s). another key issue is the Markovian assumption that neglects memory effects. Also, at a microscopic level, standard diffusion assumes and underlying Gaussian, uncorrelated stochastic process (i. e. a Brownian random walk) with well defined characteristic spatio-temporal scales. Motivated by the need to develop models of non-diffusive transport, we discuss here a class of transport models base on the use of fractional derivative operators. The models incorporates in a unified way non-Fickian transport, non-Markovian processes or memory effects, and non-diffusive scaling. At a microscopic level, the models describe an underlying stochastic process without characteristic spatio-temporal scales that generalizes the Brownian random walk. As a concrete case study to motivate and test the model, we consider transport of tracers in three-dimensional, pressure-gradient-driven turbulence. We show that in this system transport is non-diffusive and cannot be described in the context of the standard diffusion parading. In particular, the probability density function (pdf) of the radial displacements of tracers is strongly non-Gaussian with algebraic decaying tails, and the moments of the tracer displacements exhibit super-diffusive scaling. there is quantitative agreement between the turbulence transport calculations and the proposed fractional diffusion model. In particular, the model

  1. Synthesis of magnetic nanoparticles by atmospheric-pressure glow discharge plasma-assisted electrolysis

    Science.gov (United States)

    Shirai, Naoki; Yoshida, Taketo; Uchida, Satoshi; Tochikubo, Fumiyoshi

    2017-07-01

    For the synthesis of magnetic nanoparticles (NPs), we used plasma-assisted electrolysis in which atmospheric-pressure DC glow discharge using a liquid electrode is combined with electrolysis. The solution surface is exposed to positive ions or electrons in plasma. To synthesize magnetic NPs, aqueous solutions of FeCl2 or an iron electrode immersed in liquid was used to supply iron ions in the liquid. Magnetic NPs were synthesized at the plasma-liquid interface upon the electron irradiation of the liquid surface. In the case of using aqueous solutions of FeCl2, the condition of magnetic NP synthesis depended on the gas species of plasma and the chemical agent in the liquid for controlling oxidization. The amount of magnetic NPs synthesized using plasma is not very large. On the other hand, in the case of using an iron electrode immersed in NaCl solution, magnetic NPs were synthesized without using FeCl2 solutions. When plasma-assisted electrolysis was operated, the iron electrode eluted Fe cations, resulting in the formation of magnetic NPs at the plasma-liquid interface. Magnetic NP synthesis depended on the concentration of NaCl solution and discharge current. The magnetic NPs were identified to be magnetite. By using this method, more magnetite NPs were synthesized than in the case of plasma-assisted electrolysis with FeCl2 aqueous solutions. The pH of the liquid used in plasma-assisted electrolysis was important for the synthesis of magnetite NPs.

  2. Kinetic simulation technique for plasma flow in strong external magnetic field

    Science.gov (United States)

    Ebersohn, Frans H.; Sheehan, J. P.; Gallimore, Alec D.; Shebalin, John V.

    2017-12-01

    A technique for the kinetic simulation of plasma flow in strong external magnetic fields was developed which captures the compression and expansion of plasma bound to a magnetic flux tube as well as forces on magnetized particles within the flux tube. This quasi-one-dimensional (Q1D) method resolves a single spatial dimension while modeling two-dimensional effects. The implementation of this method in a Particle-In-Cell (PIC) code was verified with newly formulated test cases which include two-particle motion and particle dynamics in a magnetic mirror. Results from the Q1D method and fully two dimensional simulations were compared and error analyses performed verifying that the Q1D model reproduces the fully 2D results in the correct regimes. The Q1D method was found to be valid when the hybrid Larmor radius was less than 10% of the magnetic field scale length for magnetic field guided plasma expansions and less than 1% of the magnetic field scale length for a plasma in a converging-diverging magnetic field. The simple and general Q1D method can readily be incorporated in standard 1D PIC codes to capture multi-dimensional effects for plasma flow along magnetic fields in parameter spaces currently inaccessible by fully kinetic methods.

  3. Formation of shock waves in a discharge plasma in the presence of a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kurbanismailov, V. S., E-mail: vali-60@mail.ru; Omarov, O. A.; Ragimkhanov, G. B.; Abakarova, Kh. M.; Abbas Ali, Ali Rafid [Dagestan State University (Russian Federation)

    2016-07-15

    The effect of an external magnetic field on the dynamics of shock waves generated in an argon plasma due to both explosive processes on the cathode and expansion of the spark channel has been studied experimentally. It is shown that the expanding plasma of the cathode spot forms a shock wave and that the application of a longitudinal magnetic field decelerates the radial expansion of the cathode plasma. It is found that the intensities of some argon spectral lines increase in the presence of a magnetic field.

  4. Confinement of plasma in a magnetic bottle induced by circularly polarized laser light

    Energy Technology Data Exchange (ETDEWEB)

    Eliezer, S.; Kolka, E.; Paiss, Y. [Plasma Physics Soreq Nuclear Research Center, Yavne 70600 (Israel)

    1994-10-05

    A concept of plasma confinement using a combination of inertial and magnetic methods is suggested. A miniature magnetic bottle with the megagauss field can be induced by circularly polarized laser radiation inside a good conductor vessel containing a plasma. The laser pulses also heat the plasma to {similar_to}5 KeV during a few nanoseconds. The Lawson criteria for a DT plasma might be satisfied for densities of the order 5{center_dot}10{sup 21} cm{sup {minus}3} and confinement time about 20 nsec.(AIP) {copyright}{ital American} {ital Institute} {ital of} {ital Physics} 1994

  5. Observations of imposed ordered structures in a dusty plasma at high magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Edward, E-mail: etjr@auburn.edu; Lynch, Brian; Konopka, Uwe [Physics Department, Auburn University, Auburn, Alabama 36849 (United States); Merlino, Robert L. [Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 (United States); Rosenberg, Marlene [Department of Electrical and Computer Engineering, University of California–San Diego, La Jolla, California 92093 (United States)

    2015-03-15

    Dusty plasmas have been studied in argon, rf glow discharge plasmas at magnetic fields up to 2 T, where the electrons and ions are strongly magnetized. In this experiment, plasmas are generated between two parallel plate electrodes where the lower, powered electrode is solid and the upper, electrically floating electrode supports a semi-transparent, titanium mesh. We report on the formation of an ordered dusty plasma, where the dust particles form a spatial structure that is aligned to the mesh. We discuss possible mechanisms that may lead to the formation of the “dust grid” and point out potential implications and applications of these observations.

  6. Convective plasma stability consistent with MHD equilibrium in magnetic confinement systems with a decreasing field

    Science.gov (United States)

    Tsventoukh, M. M.

    2010-10-01

    A study is made of the convective (interchange, or flute) plasma stability consistent with equilibrium in magnetic confinement systems with a magnetic field decreasing outward and large curvature of magnetic field lines. Algorithms are developed which calculate convective plasma stability from the Kruskal-Oberman kinetic criterion and in which the convective stability is iteratively consistent with MHD equilibrium for a given pressure and a given type of anisotropy in actual magnetic geometry. Vacuum and equilibrium convectively stable configurations in systems with a decreasing, highly curved magnetic field are calculated. It is shown that, in convectively stable equilibrium, the possibility of achieving high plasma pressures in the central region is restricted either by the expansion of the separatrix (when there are large regions of a weak magnetic field) or by the filamentation of the gradient plasma current (when there are small regions of a weak magnetic field, in which case the pressure drops mainly near the separatrix). It is found that, from the standpoint of equilibrium and of the onset of nonpotential ballooning modes, a kinetic description of convective stability yields better plasma confinement parameters in systems with a decreasing, highly curved magnetic field than a simpler MHD model and makes it possible to substantially improve the confinement parameters for a given type of anisotropy. For the Magnetor experimental compact device, the maximum central pressure consistent with equilibrium and stability is calculated to be as high as β ˜ 30%. It is shown that, for the anisotropy of the distribution function that is typical of a background ECR plasma, the limiting pressure gradient is about two times steeper than that for an isotropic plasma. From a practical point of view, the possibility is demonstrated of achieving better confinement parameters of a hot collisionless plasma in systems with a decreasing, highly curved magnetic field than those

  7. Design and experimental results on a terawatt magnetically controlled plasma opening switch

    Energy Technology Data Exchange (ETDEWEB)

    Savage, M.E.; Simpson, W.W.; Mendel, C.W. Jr.; McDaniel, D.H. [Sandia National Labs., Albuquerque, NM (United States); Levine, J.S.; Tucker, T.S. [Primex Physics International, San Leandro, CA (United States)

    1998-05-01

    The magnetically controlled plasma opening switch (MCPOS) is an advanced plasma opening switch that utilizes magnetic fields to improve operation. Magnetic fields always dominate terawatt, pulsed power plasma opening switches. For that reason, the MCPOS uses controlled applied magnetic fields with magnitude comparable to the self-magnetic field of the storage inductor. One applied field holds the plasma in place while energy accumulates in the storage inductor, then another applied field pushes the plasma away from the cathode to allow energy to flow downstream. Over a ten month period, an MCPOS was designed, built, and tested on DECADE Module 2 at Physics International. The peak drive current was 1.8 MA in 250 ns. The output parameters were up to 1 MA into an electron beam load. The radiation temporal pulse width averaged 60 nanoseconds full-width at half-maximum. The peak load voltage ranged from one to two megavolts. The experiments demonstrated efficient power flow through a long, low-impedance magnetically insulated transmission line between the magnetically controlled plasma opening switch and the load.

  8. Parametric analysis of magnetic islands subject to halo-current perturbation in disrupting tokamak plasmas

    Science.gov (United States)

    Ivanov, N. V.; Kakurin, A. M.

    2017-11-01

    Results of simulation and parametric analysis of magnetic island production by helical magnetic perturbation generated under non-axisymmetric halo current are presented. Predictions are made for a cylindrical ITER-size plasma in conditions of disruption. Calculations are carried out with the TEAR code based on the visco-resistive MHD approximation. The radial distribution of the magnetic flux perturbation is calculated with account of the external helical field produced by halo current. The equations for the magnetic flux perturbation describe the dynamics of the tearing mode depending on plasma rotation. In sequence, this rotation is affected by electromagnetic forces depending on the tearing mode magnetic field and external magnetic perturbation. The coupled diffusion-type equations for the helical flux function and for the plasma rotation velocity are numerically treated in a similar way. The magnetic island behavior is analyzed for different plasma parameters expected at the Current Quench stage of disruption. The calculated width of the produced magnetic islands extends to a significant part of plasma minor radius.

  9. Extreme ultraviolet emission and confinement of tin plasmas in the presence of a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Amitava, E-mail: roy@fzu.cz, E-mail: aroy@barc.gov.in [School of Nuclear Engineering and Center for Materials Under Extreme Environment(CMUXE), Purdue University, West Lafayette, Indiana 47907 (United States); HiLASE Project, Department of Diode-pumped Lasers, Institute of Physics of the ASCR, Na Slovance 2, 18221 Prague (Czech Republic); Murtaza Hassan, Syed; Harilal, Sivanandan S.; Hassanein, Ahmed [School of Nuclear Engineering and Center for Materials Under Extreme Environment(CMUXE), Purdue University, West Lafayette, Indiana 47907 (United States); Endo, Akira; Mocek, Tomas [HiLASE Project, Department of Diode-pumped Lasers, Institute of Physics of the ASCR, Na Slovance 2, 18221 Prague (Czech Republic)

    2014-05-15

    We investigated the role of a guiding magnetic field on extreme ultraviolet (EUV) and ion emission from a laser produced Sn plasma for various laser pulse duration and intensity. For producing plasmas, planar slabs of pure Sn were irradiated with 1064 nm, Nd:YAG laser pulses with varying pulse duration (5–15 ns) and intensity. A magnetic trap was fabricated with the use of two neodymium permanent magnets which provided a magnetic field strength ∼0.5 T along the plume expansion direction. Our results indicate that the EUV conversion efficiency do not depend significantly on applied axial magnetic field. Faraday Cup ion analysis of Sn plasma show that the ion flux reduces by a factor of ∼5 with the application of an axial magnetic field. It was found that the plasma plume expand in the lateral direction with peak velocity measured to be ∼1.2 cm/μs and reduced to ∼0.75 cm/μs with the application of an axial magnetic field. The plume expansion features recorded using fast photography in the presence and absence of 0.5 T axial magnetic field are simulated using particle-in-cell code. Our simulation results qualitatively predict the plasma behavior.

  10. Extreme ultraviolet emission and confinement of tin plasmas in the presence of a magnetic field

    Science.gov (United States)

    Roy, Amitava; Murtaza Hassan, Syed; Harilal, Sivanandan S.; Endo, Akira; Mocek, Tomas; Hassanein, Ahmed

    2014-05-01

    We investigated the role of a guiding magnetic field on extreme ultraviolet (EUV) and ion emission from a laser produced Sn plasma for various laser pulse duration and intensity. For producing plasmas, planar slabs of pure Sn were irradiated with 1064 nm, Nd:YAG laser pulses with varying pulse duration (5-15 ns) and intensity. A magnetic trap was fabricated with the use of two neodymium permanent magnets which provided a magnetic field strength ˜0.5 T along the plume expansion direction. Our results indicate that the EUV conversion efficiency do not depend significantly on applied axial magnetic field. Faraday Cup ion analysis of Sn plasma show that the ion flux reduces by a factor of ˜5 with the application of an axial magnetic field. It was found that the plasma plume expand in the lateral direction with peak velocity measured to be ˜1.2 cm/μs and reduced to ˜0.75 cm/μs with the application of an axial magnetic field. The plume expansion features recorded using fast photography in the presence and absence of 0.5 T axial magnetic field are simulated using particle-in-cell code. Our simulation results qualitatively predict the plasma behavior.

  11. Magnetic field annihilation and reconnection driven by femtosecond lasers in inhomogeneous plasma

    Science.gov (United States)

    Wang, YouYuan; Li, FeiYu; Chen, Min; Weng, SuMing; Lu, QuanMing; Dong, QuanLi; Sheng, ZhengMing; Zhang, Jie

    2017-11-01

    The process of fast magnetic reconnection driven by intense ultra-short laser pulses in underdense plasma is investigated by particle-in-cell simulations. In the wakefield of such laser pulses, quasi-static magnetic fields at a few mega-Gauss are generated due to nonvanishing cross product Δ( n /γ) × p. Excited in an inhomogeneous plasma of decreasing density, the quasi-static magnetic field structure is shown to drift quickly both in lateral and longitudinal directions. When two parallel-propagating laser pulses with close focal spot separation are used, such field drifts can develop into magnetic reconnection (annihilation) in their overlapping region, resulting in the conversion of magnetic energy to kinetic energy of particles. The reconnection rate is found to be much higher than the value obtained in the Hall magnetic reconnection model. Our work proposes a potential way to study magnetic reconnection-related physics with short-pulse lasers of terawatt peak power only.

  12. Turbulence simulations of blob formation and radial propagation in toroidally magnetized plasmas

    DEFF Research Database (Denmark)

    Garcia, O.E.; Naulin, V.; Nielsen, A.H.

    2006-01-01

    Two- dimensional numerical fluid turbulence simulations demonstrating the formation and radial propagation of blob structures in toroidally magnetized plasmas are presented and analysed in detail. A salient feature of the model is a linearly unstable edge plasma region with localized sources...... of particles and heat, which is coupled to a scrape-off layer with linear damping terms for all dependent variables corresponding to transport along open magnetic field lines. The formation of blob structures is related to profile variations caused by bursting in the global turbulence level, which is due...... to a dynamical regulation by self- sustained differential rotation of the plasma layer. Radial propagation of the blob structures follows from a vertical charge polarization due to magnetic guiding centre drifts in the toroidally magnetized plasma. Statistical analysis of the particle density, radial electric...

  13. Spectroscopy on magnetically confined plasmas using electron beam ion trap spectrometers

    National Research Council Canada - National Science Library

    Graf, A T; Brockington, S; Horton, R; Howard, S; Hwang, D; Beiersdorfer, P; Clementson, J; Hill, D; May, M; Mclean, H; Wood, R; Bitter, M; Terry, J; Rowan, W L; Lepson, J K; Delgado-Aparicio, L

    2008-01-01

    Multiple spectrometers originally designed for and used at the University of California Lawrence Livermore National Laboratory's electron beam ion trap have found use at various magnetically confined plasma facilities...

  14. Scattering of magnetosonic waves in a relativistic and anisotropic magnetized plasma

    NARCIS (Netherlands)

    Moortgat, J.B.; Kuijpers, J.M.E.

    2006-01-01

    Gravitational waves (GW) propagating through a magnetized plasma excite low-frequency magnetohydrodynamic (MHD) waves. In this paper, we investigate whether these waves can produce observable radio emission at higher frequencies by scattering on an anisotropic intrinsically relativistic distribution

  15. Scattering and polarization conversion of electromagnetic waves obliquely incident on a magnetized plasma layer

    Science.gov (United States)

    Cho, Suwon

    2017-07-01

    This paper addresses the scattering of electromagnetic waves obliquely incident on a magnetized plasma layer. It is shown that the polarizations of the waves can be converted when they are obliquely incident on a magnetized plasma layer. The scattering coefficients of the incident and converted waves are computed based on the analytic solutions of a uniform magnetized plasma slab. The total transmittance and reflectance are similar to those of the normal incidence, but the individual scattering coefficients of the incident and converted waves vary, depending on the dispersion characteristics of the ordinary and extraordinary modes in the plasma. The contributions of the converted wave increase with the wave number parallel to the magnetic field but decrease as the frequency increases above the upper hybrid resonance, regardless of the parallel wave number.

  16. Research progress and status of the Magnetized Dusty Plasma Experiment (MDPX)

    Science.gov (United States)

    Thomas, Edward; Konopka, Uwe; Merlino, Robert; Rosenberg, Marlene; MDPX Team

    2017-10-01

    The addition of a magnetic field has a profound influence on the properties of a complex/dusty plasma. The Magnetized Dusty Plasma Experiment (MDPX) device at Auburn University is a flexible, high magnetic field research instrument with a mission to serve as an open access, multi-user facility for the dusty plasma and basic plasma research communities. In the last year, the MDPX device has performed a broad range of experimental studies at magnetic fields B >= 3 T; these are conditions where the electron gyro-radius is comparable to the diameter of the microparticles and the ion gyro-radius is comparable to the spacing between the microparticles. A variety of emergent phenomena are observed including a new type of imposed spatial ordering, significantly modified particle charging, coupling between ion and microparticle/nanoparticle transport, and new regimes of nanoparticle behavior. This work is supported by the US Dept. of Energy (DE-SC0016330) and the NSF (PHY-1613087).

  17. Effect of magnetic barrier on the plasma parameters in a Trimix-M galatea

    Science.gov (United States)

    Morozov, A. I.; Bugrova, A. I.; Bishaev, A. M.; Lipatov, A. S.; Kozintseva, M. V.

    2006-11-01

    The parameters of plasma trapped in a Trimix-M galatea with increased values of the magnetic barrier and the energy of a hydrogen plasma bunch injected in the trap have been determined. For a barrier magnetic field of B b ˜ 0.1 T, the plasma confinement time in the trap is τp ≈ 300 μs (which agrees with estimates obtained using formulas describing the classical transfer), the maximum electron density is n e ˜ 5 × 1013 cm-3, and the electron and ion temperatures are T e ≈ 20 eV and T i ˜ 2T e, respectively. The energy of trapped plasma is ˜110 J, and the ratio of the gaskinetic to magnetic pressure in the plasma is β0 ˜ 0.2.

  18. Dynamics of Plasma Jets and Bubbles Launched into a Transverse Background Magnetic Field

    Science.gov (United States)

    Zhang, Yue

    2017-10-01

    A coaxial magnetized plasma gun has been utilized to launch both plasma jets (open B-field) and plasma bubbles (closed B-field) into a transverse background magnetic field in the HelCat (Helicon-Cathode) linear device at the University of New Mexico. These situations may have bearing on fusion plasmas (e.g. plasma injection for tokamak fueling, ELM pacing, or disruption mitigation) and astrophysical settings (e.g. astrophysical jet stability, coronal mass ejections, etc.). The magnetic Reynolds number of the gun plasma is 100 , so that magnetic advection dominates over magnetic diffusion. The gun plasma ram pressure, ρjetVjet2 >B02 / 2μ0 , the background magnetic pressure, so that the jet or bubble can easily penetrate the background B-field, B0. When the gun axial B-field is weak compared to the gun azimuthal field, a current-driven jet is formed with a global helical magnetic configuration. Applying the transverse background magnetic field, it is observed that the n = 1 kink mode is stabilized, while magnetic probe measurements show contrarily that the safety factor q(a) drops below unity. At the same time, a sheared axial jet velocity is measured. We conclude that the tension force arising from increasing curvature of the background magnetic field induces the measured sheared flow gradient above the theoretical kink-stabilization threshold, resulting in the emergent kink stabilization of the injected plasma jet. In the case of injected bubbles, spheromak-like plasma formation is verified. However, when the spheromak plasma propagates into the transverse background magnetic field, the typical self-closed global symmetry magnetic configuration does not hold any more. In the region where the bubble toroidal field opposed the background B-field, the magneto-Rayleigh-Taylor (MRT) instability has been observed. Details of the experiment setup, diagnostics, experimental results and theoretical analysis will be presented. Supported by the National Science Foundation

  19. Low-frequency fluctuations in a pure toroidal magnetized plasma

    Indian Academy of Sciences (India)

    P K SHARMA∗, R SINGH and D BORA. Institute for Plasma Research, Bhat, Gandhinagar 382 428, India ... in plasma is relevant in many respects to controlled fusion research. It is generally believed that these .... grounded limiter of diameter 18 cm so as to keep plasma in equilibrium. A detail of the maintenance of ...

  20. SUPERDENSE GALAXIES AND THE MASS-SIZE RELATION AT LOW REDSHIFT

    Energy Technology Data Exchange (ETDEWEB)

    Poggianti, B. M.; Calvi, R.; Fasano, G.; Vulcani, B.; Bettoni, D.; Gullieuszik, M.; Omizzolo, A. [INAF-Astronomical Observatory of Padova (Italy); Bindoni, D.; D' Onofrio, M.; Moretti, A.; Valentinuzzi, T. [Astronomical Department, University of Padova (Italy); Fritz, J. [Sterrenkundig Observatorium Vakgroep Fysica en Sterrenkunde Universiteit Gent (Belgium); De Lucia, G. [INAF-Astronomical Observatory of Trieste (Italy)

    2013-01-10

    We search for massive and compact galaxies (superdense galaxies, hereafter SDGs) at z = 0.03-0.11 in the Padova-Millennium Galaxy and Group Catalogue, a spectroscopically complete sample representative of the general field population of the local universe. We find that compact galaxies with radii and mass densities comparable to high-z massive and passive galaxies represent 4.4% of all galaxies with stellar masses above 3 Multiplication-Sign 10{sup 10} M {sub Sun }, yielding a number density of 4.3 Multiplication-Sign 10{sup -4} h {sup 3} Mpc{sup -3}. Most of them are S0s (70%) or ellipticals (23%), are red, and have intermediate-to-old stellar populations, with a median luminosity-weighted age of 5.4 Gyr and a median mass-weighted age of 9.2 Gyr. Their velocity dispersions and dynamical masses are consistent with the small radii and high stellar mass estimates. Comparing with the WINGS sample of cluster galaxies at similar redshifts, the fraction of SDGs is three times smaller in the field than in clusters, and cluster SDGs are on average 4 Gyr older than field SDGs. We confirm the existence of a universal trend of smaller radii for older luminosity-weighted ages at fixed galaxy mass. As a consequence, the median mass-size relation shifts toward smaller radii for galaxies with older stars, but the effect is much more pronounced in clusters than in the field. Our results show that, on top of the well-known dependence of stellar age on galaxy mass, the luminosity-weighted age of galaxies depends on galaxy compactness at fixed mass and, for a fixed mass and radius, on environment. This effect needs to be taken into account in order not to overestimate the evolution of galaxy sizes from high to low z. Our results and hierarchical simulations suggest that a significant fraction of the massive compact galaxies at high z have evolved into compact galaxies in galaxy clusters today. When stellar age and environmental effects are taken into account, the average amount of

  1. Final Technical Report: Magnetic Reconnection in High-Energy Laser-Produced Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Germaschewski, Kai [Univ. of New Hampshire, Durham, NH (United States); Fox, William [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Bhattacharjee, Amitava [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2017-04-06

    This report describes the final results from the DOE Grant DE-SC0007168, “Fast Magnetic Reconnection in HED Laser-Produced Plasmas.” The recent generation of laboratory high-energy-density physics facilities has opened significant physics opportunities for experimentally modeling astrophysical plasmas. The goal of this proposal is to use these new tools to study fundamental problems in plasma physics and plasma astrophysics. Fundamental topics in this area involve study of the generation, amplification, and fate of magnetic fields, which are observed to pervade the plasma universe and govern its evolution. This project combined experiments at DOE laser facilities with kinetic plasma simulation to study these processes. The primary original goal of the project was to study magnetic reconnection using a new experimental platform, colliding magnetized laser-produced plasmas. However through a series of fortuitous discoveries, the work broadened out to allow significant advancement on multiple topics in laboratory astrophysics, including magnetic reconnection, Weibel instability, and collisionless shocks.

  2. Quasi-linear landau kinetic equations for magnetized plasmas: compact propagator formalism, rotation matrices and interaction

    Energy Technology Data Exchange (ETDEWEB)

    Misguich, J.H

    2004-04-01

    As a first step toward a nonlinear renormalized description of turbulence phenomena in magnetized plasmas, the lowest order quasi-linear description is presented here from a unified point of view for collisionless as well as for collisional plasmas in a constant magnetic field. The quasi-linear approximation is applied to a general kinetic equation obtained previously from the Klimontovich exact equation, by means of a generalised Dupree-Weinstock method. The so-obtained quasi-linear description of electromagnetic turbulence in a magnetoplasma is applied to three separate physical cases: -) weak electrostatic turbulence, -) purely magnetic field fluctuations (the classical quasi-linear results are obtained for cosmic ray diffusion in the 'slab model' of magnetostatic turbulence in the solar wind), and -) collisional kinetic equations of magnetized plasmas. This mathematical technique has allowed us to derive basic kinetic equations for turbulent plasmas and collisional plasmas, respectively in the quasi-linear and Landau approximation. In presence of a magnetic field we have shown that the systematic use of rotation matrices describing the helical particle motion allows for a much more compact derivation than usually performed. Moreover, from the formal analogy between turbulent and collisional plasmas, the results derived here in detail for the turbulent plasmas, can be immediately translated to obtain explicit results for the Landau kinetic equation.

  3. Plasma β Scaling of Anisotropic Magnetic Field Fluctuations in the Solar Wind Flux Tube

    Science.gov (United States)

    Sarkar, Aveek; Bhattacharjee, Amitava; Ebrahimi, Fatima

    2014-03-01

    Based on various observations, it has been suggested that at 1 AU, solar wind consists of "spaghetti"-like magnetic field structures that have the magnetic topology of flux tubes. It is also observed that the plasma fluctuation spectra at 1 AU show a plasma β dependence. Reconciling these two sets of observations and using the Invariance Principle, Bhattacharjee et al. suggested that the plasma inside every flux tube may become unstable with respect to pressure-driven instabilities and gives rise to fluctuation spectra that depend on the local plasma β. The present work is the first direct numerical simulation of such a flux tube. We solve the full magnetohydrodynamic equations using the DEBS code and show that if the plasma inside the flux tube is driven unstable by spatial inhomogeneities in the background plasma pressure, the observed nature of the fluctuating power spectra agrees reasonably well with observations, as well as the analytical prediction of Bhattacharjee et al.

  4. Plasma β scaling of anisotropic magnetic field fluctuations in the solar wind flux tube

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Aveek [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States); Bhattacharjee, Amitava; Ebrahimi, Fatima, E-mail: aveek.sarkar@unh.edu, E-mail: amitava@princeton.edu, E-mail: ebrahimi@princeton.edu [Department of Astrophysical Sciences and Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)

    2014-03-10

    Based on various observations, it has been suggested that at 1 AU, solar wind consists of 'spaghetti'-like magnetic field structures that have the magnetic topology of flux tubes. It is also observed that the plasma fluctuation spectra at 1 AU show a plasma β dependence. Reconciling these two sets of observations and using the Invariance Principle, Bhattacharjee et al. suggested that the plasma inside every flux tube may become unstable with respect to pressure-driven instabilities and gives rise to fluctuation spectra that depend on the local plasma β. The present work is the first direct numerical simulation of such a flux tube. We solve the full magnetohydrodynamic equations using the DEBS code and show that if the plasma inside the flux tube is driven unstable by spatial inhomogeneities in the background plasma pressure, the observed nature of the fluctuating power spectra agrees reasonably well with observations, as well as the analytical prediction of Bhattacharjee et al.

  5. Kinetic magnetization by fast electrons in laser-produced plasmas at sub-relativistic intensities

    Science.gov (United States)

    Pisarczyk, Tadeusz; Gus'kov, Sergey Yu.; Chodukowski, Tomasz; Dudzak, Roman; Korneev, Philipp; Demchenko, Nicolai N.; Kalinowska, Zofia; Dostal, Jan; Zaras-Szydlowska, Agnieszka; Borodziuk, Stefan; Juha, Libor; Cikhardt, Jakub; Krasa, Josef; Klir, Daniel; Cikhardtova, Balzhima; Kubes, Pavel; Krousky, Eduard; Krus, Miroslav; Ullschmied, Jiri; Jungwirth, Karel; Hrebicek, Jan; Medrik, Tomas; Golasowski, Jiri; Pfeifer, Miroslav; Renner, Oldrich; Singh, Sushil; Kar, Satyabrata; Ahmed, Hamad; Skala, Jiri; Pisarczyk, Pawel

    2017-10-01

    The problem of spontaneous magnetic field generation with nanosecond laser pulses raises a series of fundamental questions, including the intrinsic magnetization mechanisms in laser-driven plasmas and the understanding of charge-discharge processes in the irradiated target. These two issues are tightly bound as the charge-discharge processes are defined by the currents, which have in turn a feedback by magnetic fields in the plasma. Using direct polaro-interferometric measurements and theoretical analysis, we show that at parameters related to the PALS laser system ( 1.315 μ m, 350 ps, and 1016 W/cm2), fast electrons play a decisive role in the generation of magnetic fields in the laser-driven plasma. Spatial distributions of electric currents were calculated from the measured magnetic field and plasma density distributions. The obtained results revealed the characteristics of strong currents observed in capacitor-coil magnetic generation schemes and open a new approach to fundamental studies related to magnetized plasmas.

  6. Magnetic Diagnostics For Equilibrium Reconstruction And Realtime Plasma Control In NSTX-Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Gerhardt, Stefan P. [PPPL; Erickson, Keith [PPPL; Kaita, Robert [PPPL; Lawson, John [PPPL; Mozulay, Robert [PPPL; Mueller, Dennis [PPPL; Que, Weiguo [PPPL; Rahman, Nabidur [PPPL; Schneider, Hans [PPPL; Smalley, Gustav [PPPL; Tresemer, Kelsey [PPPL

    2014-06-01

    This paper describes aspects of magnetic diagnostics for realtime control in NSTX-U. The sensor arrangement on the upgraded center column is described. New analog and digital circuitry for processing the plasma current rogowski data are presented. An improved algorithm for estimating the plasma vertical velocity for feedback control is presented.

  7. Anisotropic diffusion across an external magnetic field and large-scale fluctuations in magnetized plasmas.

    Science.gov (United States)

    Holod, I; Zagorodny, A; Weiland, J

    2005-04-01

    The problem of random motion of charged particles in an external magnetic field is studied under the assumption that the Langevin sources produce anisotropic diffusion in velocity space and the friction force is dependent on the direction of particle motion. It is shown that in the case under consideration, the kinetic equation describing particle transitions in phase space is reduced to the equation with a Fokker-Planck collision term in the general form (non-isotropic friction coefficient and nonzero off-diagonal elements of the diffusion tensor in the velocity space). The solution of such an equation has been obtained and the explicit form of the transition probability is found. Using the obtained transition probability, the mean-square particle displacements in configuration and velocity space were calculated and compared with the results of numerical simulations, showing good agreement. The obtained results are used to generalize the theory of large-scale fluctuations in plasmas to the case of anisotropic diffusion across an external magnetic field. Such diffusion is expected to be observed in the case of an anisotropic k spectrum of fluctuations generating random particle motion (for example, in the case of drift-wave turbulence).

  8. Enhanced Plasma Confinement in a Magnetic Well by Whistler Waves

    DEFF Research Database (Denmark)

    Balmashnov, A. A.; Juul Rasmussen, Jens

    1981-01-01

    The propagation of whistler waves in a magnetic field of mirror configuration is investigated experimentally. The strong interaction between waves and particles at the electron-cyclotron resonance leads to enhanced confinement in the magnetic well.......The propagation of whistler waves in a magnetic field of mirror configuration is investigated experimentally. The strong interaction between waves and particles at the electron-cyclotron resonance leads to enhanced confinement in the magnetic well....

  9. Magnetic Dipole Inflation with Cascaded ARC and Applications to Mini-Magnetospheric Plasma Propulsion

    Science.gov (United States)

    Giersch, L.; Winglee, R.; Slough, J.; Ziemba, T.; Euripides, P.

    2003-01-01

    Mini-Magnetospheric Plasma Propulsion (M2P2) seeks to create a plasma-inflated magnetic bubble capable of intercepting significant thrust from the solar wind for the purposes of high speed, high efficiency spacecraft propulsion. Previous laboratory experiments into the M2P2 concept have primarily used helicon plasma sources to inflate the dipole magnetic field. The work presented here uses an alternative plasma source, the cascaded arc, in a geometry similar to that used in previous helicon experiments. Time resolved measurements of the equatorial plasma density have been conducted and the results are discussed. The equatorial plasma density transitions from an initially asymmetric configuration early in the shot to a quasisymmetric configuration during plasma production, and then returns to an asymmetric configuration when the source is shut off. The exact reasons for these changes in configuration are unknown, but convection of the loaded flux tube is suspected. The diffusion time was found to be an order of magnitude longer than the Bohm diffusion time for the period of time after the plasma source was shut off. The data collected indicate the plasma has an electron temperature of approximately 11 eV, an order of magnitude hotter than plasmas generated by cascaded arcs operating under different conditions. In addition, indirect evidence suggests that the plasma has a beta of order unity in the source region.

  10. Experimental investigation of axial plasma injection into a magnetic dipole field

    DEFF Research Database (Denmark)

    Jensen, Vagn Orla

    1968-01-01

    A high-density helium plasma, accelerated from a conical pinch, is injected axially into a magnetic dipole field. Magnetic probe measurements show that, near the axis, a compression of the field is super-imposed on the standard diamagnetic depression. The compression starts downstream and moves...

  11. Combined influence of azimuthal and axial magnetic fields on resonant electron acceleration in plasma

    Science.gov (United States)

    Singh, Arvinder; Rajput, Jyoti; Kant, Niti

    2017-11-01

    Resonant enhancement in electron acceleration due to a circularly polarized laser pulse in plasma, under the combined influence of external azimuthal and axial magnetic fields, is studied. We have investigated direct electron acceleration in plasma by employing a relativistic single particle simulation. The plasma is magnetized with an azimuthal magnetic field applied in the perpendicular plane and an axial magnetic field applied along the direction of laser beam propagation. Resonance takes place between electron and electric field of the laser pulse for the optimum value of the combined magnetic field, which supports electron acceleration to higher energies, up to the betatron resonance point. The optimum value of these magnetic fields is highly sensitive to laser initial intensity and laser initial spot size. The effects of laser intensity, initial spot size, and laser pulse duration are taken into consideration in optimizing the magnetic field for efficient electron acceleration. Higher electron energy gain, of the order of GeV, is observed by employing terawatt circularly polarized laser pulses in plasma under the influence of combined magnetic field of about 10 MG.

  12. Exact Time-Dependent Nonlinear Dispersive Wave Solutions in Compressible Magnetized Plasmas Exhibiting Collapse

    Science.gov (United States)

    Chakrabarti, Nikhil; Maity, Chandan; Schamel, Hans

    2011-04-01

    Compressional waves in a magnetized plasma of arbitrary resistivity are treated with the Lagrangian fluid approach. An exact nonlinear solution with a nontrivial space and time dependence is obtained with boundary conditions as in Harris’ current sheet. The solution shows competition among hydrodynamic convection, magnetic field diffusion, and dispersion. This results in a collapse of density and the magnetic field in the absence of dispersion. The dispersion effects arrest the collapse of density but not of the magnetic field. A possible application is in the early stage of magnetic star formation.

  13. Defective iron-oxide nanoparticles synthesised by high temperature plasma processing: a magnetic characterisation versus temperature.

    Science.gov (United States)

    Balasubramanian, C; Joseph, B; Orpe, P B; Saini, N L; Mukherjee, S; Dziedzic-Kocurek, K; Stanek, J; Di Gioacchino, D; Marcelli, A

    2016-11-04

    Magnetic properties and phase compositions of iron-oxide nanoparticles synthesised by a high temperature arc plasma route have been investigated by Mössbauer spectroscopy and high harmonic magnetic AC susceptibility measurements, and correlated with morphological and structural properties for different synthesis conditions. The Mössbauer spectra precisely determined the presence of different iron-oxide fractions in the investigated nanoparticles, while the high harmonic magnetic susceptibility measurements revealed the occurrence of metastable magnetic phases evolving in temperature and time. This study illustrates magnetic properties and dynamics of the magnetic configurations of iron-oxide nanoparticles grown by high temperature plasma, a process less explored so far but extremely useful for synthesising large numbers of nanoparticles for industrial applications.

  14. Magnetic turbulence in a table-top laser-plasma relevant to astrophysical scenarios

    Science.gov (United States)

    Chatterjee, Gourab; Schoeffler, Kevin M.; Kumar Singh, Prashant; Adak, Amitava; Lad, Amit D.; Sengupta, Sudip; Kaw, Predhiman; Silva, Luis O.; Das, Amita; Kumar, G. Ravindra

    2017-06-01

    Turbulent magnetic fields abound in nature, pervading astrophysical, solar, terrestrial and laboratory plasmas. Understanding the ubiquity of magnetic turbulence and its role in the universe is an outstanding scientific challenge. Here, we report on the transition of magnetic turbulence from an initially electron-driven regime to one dominated by ion-magnetization in a laboratory plasma produced by an intense, table-top laser. Our observations at the magnetized ion scale of the saturated turbulent spectrum bear a striking resemblance with spacecraft measurements of the solar wind magnetic-field spectrum, including the emergence of a spectral kink. Despite originating from diverse energy injection sources (namely, electrons in the laboratory experiment and ion free-energy sources in the solar wind), the turbulent spectra exhibit remarkable parallels. This demonstrates the independence of turbulent spectral properties from the driving source of the turbulence and highlights the potential of small-scale, table-top laboratory experiments for investigating turbulence in astrophysical environments.

  15. Electron transport in the plasma edge with rotating resonant magnetic perturbations at the TEXTOR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Stoschus, Henning

    2011-10-13

    Small three-dimensional (3D) magnetic perturbations can be used as a tool to control the edge plasma parameters in magnetically confined plasmas in high confinement mode (''H-mode'') to suppress edge instabilities inherent to this regime, the Edge Localized Modes (ELMs). In this work, the impact of rotating 3D resonant magnetic perturbation (RMP) fields on the edge plasma structure characterized by electron density and temperature fields is investigated. We study a low confinement (L-mode) edge plasma (r/a>0.9) with high resistivity (edge electron collisionality {nu}{sup *}{sub e}>4) at the TEXTOR tokamak. The plasma structure in the plasma edge is measured by a set of high resolution diagnostics: a fast CCD camera ({delta}t=20 {mu}s) is set up in order to visualize the plasma structure in terms of electron density variations. A supersonic helium beam diagnostic is established as standard diagnostic at TEXTOR to measure electron density n{sub e} and temperature T{sub e} with high spatial ({delta}r=2 mm) and temporal resolution ({delta}t=20 {mu}s). The measured plasma structure is compared to modeling results from the fluid plasma and kinetic neutral transport code EMC3-EIRENE. A sequence of five new observations is discussed: (1) Imaging of electron density variations in the plasma edge shows that a fast rotating RMP field imposes an edge plasma structure, which rotates with the external RMP rotation frequency of vertical stroke {nu}{sub RMP} vertical stroke =1 kHz. (2) Measurements of the electron density and temperature provide strong experimental evidence that in the far edge a rotating 3D scrape-off layer (SOL) exists with helical exhaust channels to the plasma wall components. (3) Radially inward, the plasma structure at the next rational flux surface is found to depend on the relative rotation between external RMP field and intrinsic plasma rotation. For low relative rotation the plasma structure is dominated by a particle and energy loss

  16. DoE Plasma Center for Momentum Transport and Flow Self-Organization in Plasmas: Non-linear Emergent Structure Formation in magnetized Plasmas and Rotating Magnetofluids

    Energy Technology Data Exchange (ETDEWEB)

    Forest, Cary B. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics

    2016-11-10

    This report covers the UW-Madison activities that took place within a larger DoE Center Administered and directed by Professor George Tynan at the University of California, San Diego. The work at Wisconsin will also be covered in the final reporting for the entire center, which will be submitted by UCSD. There were two main activities, one experimental and one that was theoretical in nature, as part of the Center activities at the University of Wisconsin, Madison. First, the Center supported an experimentally focused postdoc (Chris Cooper) to carry out fundamental studies of momentum transport in rotating and weakly magnetized plasma. His experimental work was done on the Plasma Couette Experiment, a cylindrical plasma confinement device, with a plasma flow created through electromagnetically stirring plasma at the plasma edge facilitated by arrays of permanent magnets. Cooper's work involved developing optical techniques to measure the ion temperature and plasma flow through Doppler-shifted line radiation from the plasma argon ions. This included passive emission measurements and development of a novel ring summing Fabry-Perot spectroscopy system, and the active system involved using a diode laser to induce fluorescence. On the theoretical side, CMTFO supported a postdoc (Johannes Pueschel) to carry out a gyrokinetic extension of residual zonal flow theory to the case with magnetic fluctuations, showing that magnetic stochasticity disrupts zonal flows. The work included a successful comparison with gyrokinetic simulations. This work and its connection to the broader CMTFO will be covered more thoroughly in the final CMTFO report from Professor Tynan.

  17. Electrostatic surface waves on a magnetized quantum plasma half-space

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Engineering Physics, Kermanshah University of Technology, Kermanshah, Iran and Department of Nano Sciences, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of)

    2016-03-15

    A theory of electrostatic surface waves on a quantum plasma half-space is developed with the inclusion of external magnetic field effects for the geometry in which the magnetic field is parallel to the surface and the direction of propagation is perpendicular to the magnetic field. A general analytical expression for dispersion relation of surface waves is obtained by solving Poisson and quantum magnetohydrodynamic equations with appropriate quantum boundary conditions.

  18. The general dielectric tensor for bi-kappa magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Gaelzer, R., E-mail: rudi.gaelzer@ufrgs.br; Ziebell, L. F., E-mail: luiz.ziebell@ufrgs.br; Meneses, A. R., E-mail: anemeneses@gmail.com [Instituto de Física, UFRGS, 91501-970 Porto Alegre, RS (Brazil)

    2016-06-15

    In this paper, we derive the dielectric tensor for a plasma containing particles described by an anisotropic superthermal (bi-kappa) velocity distribution function. The tensor components are written in terms of the two-variables kappa plasma special functions, recently defined by Gaelzer and Ziebell [Phys. Plasmas 23, 022110 (2016)]. We also obtain various new mathematical properties for these functions, which are useful for the analytical treatment, numerical implementation, and evaluation of the functions and, consequently, of the dielectric tensor. The formalism developed here and in the previous paper provides a mathematical framework for the study of electromagnetic waves propagating at arbitrary angles and polarizations in a superthermal plasma.

  19. The general dielectric tensor for bi-kappa magnetized plasmas

    CERN Document Server

    Gaelzer, Rudi; Meneses, Anelise Ramires

    2016-01-01

    In this paper we derive the dielectric tensor for a plasma containing particles described by an anisotropic superthermal (bi-kappa) velocity distribution function. The tensor components are written in terms of the two-variables kappa plasma special functions, recently defined by Gaelzer and Ziebell [Phys. Plasmas 23, 022110 (2016)]. We also obtain various new mathematical properties for these functions, which are useful for the analytical treatment, numerical implementation and evaluation of the functions and, consequently, of the dielectric tensor. The formalism developed here and in the previous paper provides a mathematical framework for the study of electromagnetic waves propagating at arbitrary angles and polarizations in a superthermal plasma.

  20. Viscous Coupling of Momentum from a Magnetized to an Unmagnetized Plasma

    Science.gov (United States)

    Katz, Noam; Collins, Cami; Khalzov, Ivan; Brown, Ben; Forest, Cary

    2011-10-01

    In order to drive rotation in the Plasma Couette Experiment (PCX), we must understand how momentum couples from the magnetized edge into the unmagnetized core. PCX uses rings of alternating-polarity permanent magnets to provide edge confinement, resulting in a well-contained, cylindrical and unmagnetized plasma. The rotation is driven at the edge with a J ×B torque, and viscous coupling is then required to achieve rotation in the bulk plasma. The plasma viscosity has not been well-measured in previous experiments, but PCX provides an excellent setup for its measurement. I will discuss progress towards explaining and optimizing the PCX velocity profile. This problem involves an anisotropic viscosity tensor, neutral drag, and strong gradients in the magnetic field. Work supported by DOE Fusion Energy Postdoctoral Fellowship.

  1. Progress towards experimental realization of extreme-velocity flow-dominated magnetized plasmas

    Science.gov (United States)

    Weber, T. E.; Adams, C. S.; Welch, D. R.; Kagan, G.; Bean, I. A.; Henderson, B. R.; Klim, A. J.

    2017-10-01

    Interactions of flow-dominated plasmas with other plasmas, neutral gases, magnetic fields, solids etc., take place with sufficient velocity that kinetic energy dominates the dynamics of the interaction (as opposed to magnetic or thermal energy, which dominates in most laboratory plasma experiments). Building upon progress made by the Magnetized Shock Experiment (MSX) at LANL, we are developing the experimental and modeling capability to increase our ultimate attainable plasma velocities well in excess of 1000 km/s. Ongoing work includes designing new pulsed power switches, triggering, and inductive adder topologies; development of novel high-speed optical diagnostics; and exploration of new numerical techniques to specifically model the unique physics of translating/stagnating flow-dominated plasmas. Furthering our understanding of the physical mechanisms of energy conversion from kinetic to other forms, such as thermal energy, non-thermal tails/accelerated populations, enhanced magnetic fields, and radiation (both continuum and line), has wide-ranging significance in basic plasma science, astrophysics, and plasma technology applications such as inertial confinement fusion and intense radiation sources. This work is supported by the U.S. Department of Energy, National Nuclear Security Administration. LA-UR-17-25786.

  2. Performance evaluation of a permanent ring magnet based helicon plasma source for negative ion source research

    Science.gov (United States)

    Pandey, Arun; Bandyopadhyay, M.; Sudhir, Dass; Chakraborty, A.

    2017-10-01

    Helicon wave heated plasmas are much more efficient in terms of ionization per unit power consumed. A permanent magnet based compact helicon wave heated plasma source is developed in the Institute for Plasma Research, after carefully optimizing the geometry, the frequency of the RF power, and the magnetic field conditions. The HELicon Experiment for Negative ion-I source is the single driver helicon plasma source that is being studied for the development of a large sized, multi-driver negative hydrogen ion source. In this paper, the details about the single driver machine and the results from the characterization of the device are presented. A parametric study at different pressures and magnetic field values using a 13.56 MHz RF source has been carried out in argon plasma, as an initial step towards source characterization. A theoretical model is also presented for the particle and power balance in the plasma. The ambipolar diffusion process taking place in a magnetized helicon plasma is also discussed.

  3. High-power broadband plasma maser with magnetic self-insulation

    Science.gov (United States)

    Litvin, Vitaliy O.; Loza, Oleg T.

    2018-01-01

    Presented in this paper are the results of a particle-in-cell modelling of a novel high-power microwave (HPM) source which combines the properties of two devices. The first prototype is a magnetically insulated transmission line oscillator (MILO), an HPM self-oscillator which does not need an external magnetic field and irradiates a narrow spectrum depending on its iris-loaded slow-wave structure. The second prototype is a plasma maser, a Cherenkov HPM amplifier driven by a high-current relativistic electron beam propagating in a strong external magnetic field in plasma which acts as a slow-wave structure. The radiation frequency of plasma masers mainly depends on an easily variable plasma concentration; hence, their spectrum may overlap a few octaves. The plasma-based HPM device described in this paper operates without an external magnetic field: it looks like an MILO in which the iris-loaded slow-wave structure is substituted by a hollow plasma tube. The small pulse duration of ˜1.5 ns prevents a feedback rise in the 20-cm long generation section so that the device operates as a noise amplifier. Unlike conventional ultra wideband generators, the spectrum depends not only on the pulse duration but mainly on plasma, so the operation frequency of the device ranges within 12 GHz. For irradiated frequencies above 2 GHz, the total pulse energy efficiency of 7% is demonstrated at the HPM power level ˜1 GW.

  4. Laser induced fluorescence measurements of axial velocity, velocity shear, and parallel ion temperature profiles during the route to plasma turbulence in a linear magnetized plasma device

    Science.gov (United States)

    Chakraborty Thakur, S.; Adriany, K.; Gosselin, J. J.; McKee, J.; Scime, E. E.; Sears, S. H.; Tynan, G. R.

    2016-11-01

    We report experimental measurements of the axial plasma flow and the parallel ion temperature in a magnetized linear plasma device. We used laser induced fluorescence to measure Doppler resolved ion velocity distribution functions in argon plasma to obtain spatially resolved axial velocities and parallel ion temperatures. We also show changes in the parallel velocity profiles during the transition from resistive drift wave dominated plasma to a state of weak turbulence driven by multiple plasma instabilities.

  5. Viscosity of two-dimensional strongly coupled dusty plasma modified by a perpendicular magnetic field.

    Science.gov (United States)

    Feng, Yan; Lin, Wei; Murillo, M S

    2017-11-01

    Transport properties of two-dimensional (2D) strongly coupled dusty plasmas have been investigated in detail, but never for viscosity with a strong perpendicular magnetic field; here, we examine this scenario using Langevin dynamics simulations of 2D liquids with a binary Yukawa interparticle interaction. The shear viscosity η of 2D liquid dusty plasma is estimated from the simulation data using the Green-Kubo relation, which is the integration of the shear stress autocorrelation function. It is found that, when a perpendicular magnetic field is applied, the shear viscosity of 2D liquid dusty plasma is modified substantially. When the magnetic field is increased, its viscosity increases at low temperatures, while at high temperatures its viscosity diminishes. It is determined that these different variational trends of η arise from the different behaviors of the kinetic and potential parts of the shear stress under external magnetic fields.

  6. Formation of a field reversed configuration for magnetic and electrostatic confinement of plasma

    Science.gov (United States)

    Rostoker, Norman; Binderbauer, Michl

    2003-12-16

    A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

  7. Magnetic and electrostatic confinement of plasma with tuning of electrostatic field

    Science.gov (United States)

    Rostoker, Norman [Irvine, CA; Binderbauer, Michl [Irvine, CA; Qerushi, Artan [Irvine, CA; Tahsiri, Hooshang [Irvine, CA

    2008-10-21

    A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

  8. Study on electromagnetic plasma propulsion using rotating magnetic field acceleration scheme

    Science.gov (United States)

    Furukawa, T.; Takizawa, K.; Kuwahara, D.; Shinohara, S.

    2017-04-01

    As one of the electromagnetic plasma acceleration systems, we have proposed a rotating magnetic field (RMF) acceleration scheme to overcome the present problem of direct plasma-electrode interactions, leading to a short lifetime with a poor plasma performance due to contamination. In this scheme, we generate a plasma by a helicon wave excited by a radio frequency (rf) antenna which has no direct-contact with a plasma. Then, the produced plasma is accelerated by the axial Lorentz force fz = jθ × Br (jθ is an azimuthal current induced by RMF, and Br is an external radial magnetic field). Erosion of electrodes and contamination are not expected in this total system since RMF coils and an rf antenna do not have contact with the plasma directly. Here, we have measured the plasma parameters (electron density ne and axial ion velocity vi) to demonstrate this RMF acceleration scheme by the use of AC currents in two sets of opposing coils to generate a RMF. The maximum increasing rate Δvi /vi was ˜28% (maximum vi of ˜3 km/s), while the density increasing rate of Δne/ne is ˜ 70% in the case of a RMF current frequency fRMF of 3 MHz, which showed a better plasma performance than that with fRMF = 5 MHz. Moreover, thrust characteristics such as a specific impulse and a thrust efficiency were discussed, although a target plasma was not optimized.

  9. Particle Acceleration during Magnetic Reconnection in a Low-beta Plasma

    Science.gov (United States)

    Li, Xiaocan; Guo, Fan; Li, Hui; Li, Gang

    2017-07-01

    Magnetic reconnection is a primary mechanism for particle energization in space and astrophysical plasmas. By carrying out two-dimensional (2D) fully kinetic simulations, we study particle acceleration during magnetic reconnection in plasmas with different plasma β (the ratio between the thermal pressure and the magnetic pressure). For the high-β cases, we do not observe significant particle acceleration. In the low-β regime (β accelerated particles integrated over the whole simulation box appears highly non-thermal, it is actually the superposition of a series of distributions in different sectors of a 2D magnetic island. Each of those distributions has only a small non-thermal component compared with its thermal core. By tracking a large number of particles, we show that particles get energized in X-line regions, contracting magnetic islands, and magnetic island coalescence regions. We obtain the particle energization rate {\\boldsymbol{j}}\\cdot {\\boldsymbol{E}} by averaging over particle drift motions and find that it agrees well with the particle kinetic energy change. We quantify the contribution of curvature drift, gradient drift, polarization drift, magnetization, non-gyrotropic effect, and parallel electric field in different acceleration regions. We find that the major energization is due to particle curvature drift along the motional electric field. The other particle motions contribute less but may become important in different acceleration regions. The highly efficient particle energization in low-β plasmas may help us understand the strong particle energization in solar flares and accretion disk coronae.

  10. Effect of magnetic field on the phase transition in a dusty plasma

    Science.gov (United States)

    Jaiswal, S.; Hall, T.; LeBlanc, S.; Mukherjee, R.; Thomas, E.

    2017-11-01

    The formation of a self-consistent crystalline structure is a well-known phenomenon in complex plasmas. In most experiments, the pressure and rf power are the main controlling parameters in determining the phase of the system. We have studied the effect of the externally applied magnetic field on the configuration of plasma crystals, suspended in the sheath of a radio-frequency discharge using the Magnetized Dusty Plasma Experiment device. Experiments are performed at a fixed pressure and rf power where a crystalline structure is formed within a confining ring. The magnetic field is then increased from 0 to 1.28 T. We report on the breakdown of the crystalline structure with the increasing magnetic field. The magnetic field affects the dynamics of the plasma particles and first leads to a rotation of the crystal. At a higher magnetic field, there is a radial variation (shear) in the angular velocity of the moving particles which we believe to lead to the melting of the crystal. This melting is confirmed by evaluating the variation of the pair correlation function as a function of magnetic field.

  11. Effect of magnetic field on the phase transition in dusty plasma

    Science.gov (United States)

    Jaiswal, Surabhi; Thomas, Edward; Mukherjee, Rupak

    2017-10-01

    The formation of self-consistent crystalline structure is a well-known phenomenon in complex plasmas. In most experiments the pressure and rf power are the main controlling parameter in determining the phase of the system. We have studied the effect of externally applied magnetic field on the configuration of plasma crystals, suspended in the sheath of a radio-frequency discharge using the Magnetized Dusty Plasma Experiment (MDPX) device. Experiments are performed at a fixed pressure and rf power where a crystalline structure formed within the confining ring, but ramping the magnetic field up to 1.28 T. We report on the breakdown of the crystalline structure with increasing magnetic field. The magnetic field affects the dynamics of the plasma particles and first leads to a rotation of the crystal. At higher magnetic field, there is a radial variation (shear) in the angular velocity of the moving particles which we believe leads to the melting of the crystal. This melting is confirmed by evaluating the variation of the pair correlation function as a function of magnetic field. This work was supported by the US Dept. of Energy, DE - SC0010485.

  12. Highly Supersonic Ion Pulses in a Collisionless Magnetized Plasma

    DEFF Research Database (Denmark)

    Juul Rasmussen, Jens; Schrittwieser, R.

    1982-01-01

    The initial transient response of a collisionless plasma to a high positive voltage step is investigated. Four different pulses are observed. An electron plasma wave pulse is followed by an ion burst. The latter is overtaken and absorbed by a highly supersonic ion pulse. Thereafter, an ion...

  13. The dynamics of plasma with a horizontal magnetic field in the chromosphere

    Science.gov (United States)

    Alekseeva, Liliya; Kshevetskii, Sergey P.

    The properties of the solar chromosphere are usually discussed from the standpoint of the magnetic coupling between the chromospheric and coronal plasmas, whereas the dynamical properties of the chromosphere itself are poorly investigated. We numerically study these properties. Since about 95% of the magnetic flux issuing from the photosphere closes below the coronal heights (so that the chromospheric magnetic fieldlargely consists of the apical horizontal segments of the field lines), we assume the magnetic field in our problem to be horizontal. All physical quantities are considered to be constant along the straight parallel magnetic field lines. We solve a fully self-consistent, two-dimensional initial-value problem for nonlinear collisional MHD equations of the electrically and thermally conducting ion-electron plasma, with the velocity and electric-current vectors normal to the magnetic field. Our technique makes it possible to describe small-scale turbulence and discontinuities, automatically passing, whenever necessary, to calculations in the class of generalized functions. This allows us to obtain nonlinear solutions for comparatively long time intervals even if small-scale perturbations develop. The plasma is assumed to be initially motionless, with a constant initial temperature of 50 000 K. Even if the magnetic and gas pressure are initially balanced, we see the development of large-scale flows. They set in in the area of enhanced electric currents, i.e., near the bounding zone of the magnetic configuration. This phenomenon is due to a pinch instability, in a broad sense (with an accidentally penetratiing plasma ``tongue'' of increased magnetic field and a resultant spreading of the ambient plasma from this point, followed by the further penetration of the "tongue''; this is an analog of the sausage instability of the laboratory Z-pinch without, however, any symmetry in the initial magnetic field and the ultimate breaking of the electric current). If the

  14. Oscillating two-stream instability in a magnetized electron-positron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tinakiche, Nouara [Department of Physics, Faculty of Science, U.M.B.B, Boumerdes 35000 (Algeria); Faculty of Physics, U.S.T.H.B, Algiers 16111 (Algeria); Annou, R. [Faculty of Physics, U.S.T.H.B, Algiers 16111 (Algeria)

    2015-04-15

    Oscillating two-stream instability (OTSI) in a magnetized electron-ion plasma has been thoroughly studied, e.g., in ionospheric heating experiments [C. S. Liu and V. K. Tripathi, Interaction of Electromagnetic Waves With Electron Beams and Plasmas (World Scientific, 1994); V. K. Tripathi and P. V. Siva Rama Prasad, J. Plasma Phys. 41, 13 (1989); K. Ramachandran and V. K. Tripathi, IEEE Trans. Plasma Sci. 25, 423 (1997)]. In this paper, OTSI is investigated in a magnetized electron-positron-ion plasma. The dispersion relation of the process is established. The pump field threshold, along with the maximum growth rate of the instability is assessed using the Arecibo and HAARP parameters.

  15. Spectroscopic measurement of high-frequency electric fields in the interaction of explosive debris plasma with magnetized background plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bondarenko, A. S., E-mail: AntonBondarenko@ymail.com; Schaeffer, D. B.; Everson, E. T.; Clark, S. E.; Constantin, C. G.; Niemann, C. [Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, California 90095 (United States)

    2014-12-15

    The collision-less transfer of momentum and energy from explosive debris plasma to magnetized background plasma is a salient feature of various astrophysical and space environments. While much theoretical and computational work has investigated collision-less coupling mechanisms and relevant parameters, an experimental validation of the results demands the measurement of the complex, collective electric fields associated with debris-background plasma interaction. Emission spectroscopy offers a non-interfering diagnostic of electric fields via the Stark effect. A unique experiment at the University of California, Los Angeles, that combines the Large Plasma Device (LAPD) and the Phoenix laser facility has investigated the marginally super-Alfvénic, quasi-perpendicular expansion of a laser-produced carbon (C) debris plasma through a preformed, magnetized helium (He) background plasma via emission spectroscopy. Spectral profiles of the He II 468.6 nm line measured at the maximum extent of the diamagnetic cavity are observed to intensify, broaden, and develop equally spaced modulations in response to the explosive C debris, indicative of an energetic electron population and strong oscillatory electric fields. The profiles are analyzed via time-dependent Stark effect models corresponding to single-mode and multi-mode monochromatic (single frequency) electric fields, yielding temporally resolved magnitudes and frequencies. The proximity of the measured frequencies to the expected electron plasma frequency suggests the development of the electron beam-plasma instability, and a simple saturation model demonstrates that the measured magnitudes are feasible provided that a sufficiently fast electron population is generated during C debris–He background interaction. Potential sources of the fast electrons, which likely correspond to collision-less coupling mechanisms, are briefly considered.

  16. Optical diagnostics of a low frequency instability rotating around a magnetized plasma column

    Energy Technology Data Exchange (ETDEWEB)

    Escarguel, A. [Universite de Provence, Centre de Saint Jerome, Lab. PIIM, UMR 6633 CNRS, 13 - Marseille (France)

    2010-01-15

    An argon magnetized plasma column is created with primary energetic electrons in the Mistral device. Low frequency instabilities regularly rotating around this column are observed with an ultra-fast camera and a spectroscopic device. Experimental results coupled to a coronal code show the presence of a few percents of fast (hot) electrons inside the ejected plasma. It also shows that ultra-fast camera analysis of the ejected plasma can only give information on the primary electron population. Finally, these results suggest that the radial decrease of the light emitted by the ejected plasma is essentially due to the radial decrease of the mean energy of the hot electrons. (author)

  17. Basic investigations of electrostatic turbulence and its interaction with plasma and suprathermal ions in a simple magnetized toroidal plasma

    Science.gov (United States)

    Fasoli, A.; Avino, F.; Bovet, A.; Furno, I.; Gustafson, K.; Jolliet, S.; Loizu, J.; Malinverni, D.; Ricci, P.; Riva, F.; Theiler, C.; Spolaore, M.; Vianello, N.

    2013-06-01

    Progress in basic understanding of turbulence and its influence on the transport both of the plasma bulk and of suprathermal components is achieved in the TORPEX simple magnetized torus. This configuration combines a microwave plasma production scheme with a quasi-equilibrium generated by a toroidal magnetic field, onto which a small vertical component is superimposed, simulating a simplified form of tokamak scrape-off layers. After having clarified the formation of blobs in ideal interchange turbulence, TORPEX experiments elucidated the mechanisms behind the blob motion, with a general scaling law relating their size and speed. The parallel currents associated with the blobs, responsible for the damping of the charge separation that develops inside them, hence determining their cross-field velocity, have been measured. The blob dynamics is influenced by creating convective cells with biased electrodes, arranged in an array on a metal limiter. Depending on the biasing scheme, radial and vertical blob velocities can be varied. Suprathermal ion transport in small-scale turbulence is also investigated on TORPEX. Suprathermal ions are generated by a miniaturized lithium source, and are detected using a movable double-gridded energy analyser. We characterize vertical and radial spreading of the ion beam, associated with the ideal interchange-dominated plasma turbulence, as a function of the suprathermal ion energy and the plasma temperature. Experimental results are in good agreement with global fluid simulations, including in cases of non-diffusive behaviour. To investigate the interaction of plasma and suprathermal particles with instabilities and turbulence in magnetic configurations of increasing complexity, a closed field line configuration has recently been implemented on TORPEX, based on a current-carrying wire suspended in the vacuum chamber. First measurements indicate the creation of circular symmetric profiles centred on the magnetic axis, and instabilities

  18. Turbulent transport of impurities in a magnetized plasma; Transport turbulent d'impuretes dans un plasma magnetise

    Energy Technology Data Exchange (ETDEWEB)

    Dubuit, N

    2006-10-15

    This work deals with the transport of impurities in magnetically confined thermonuclear plasmas. The accumulation of impurities in the core of the plasma would imply dramatic losses of energy that may lead to the extinction of the plasma. On the opposite, the injection of impurities in the plasma edge is considered as an efficient means to extract heat without damaging the first wall. The balance between these 2 contradictory constraints requires an accurate knowledge of the impurity transport inside the plasma. The effect of turbulence, the main transport mechanism for impurities is therefore a major issue. In this work, the complete formula of a turbulent flow of impurities for a given fluctuation spectrum has been inferred. The origin and features of the main accumulation processes have been identified. The main effect comes from the compressibility of the electrical shift speed in a plane perpendicular to the magnetic field. This compressibility appears to be linked to the curvature of the magnetic field. A less important effect is a thermal-diffusion process that is inversely proportional to the number of charges and then disappears for most type of impurities except the lightest. This effect implies an impurity flux proportional to the temperature gradient and its direction can change according to the average speed of fluctuations. A new version of the turbulence code TRB has been developed. This new version allows the constraints of the turbulence not by the gradients but by the flux which is more realistic. The importance of the processes described above has been confirmed by a comparison between calculation and experimental data from Tore-supra and the Jet tokamak. The prevailing role of the curvature of the magnetic field in the transport impurity is highlighted. (A.C.)

  19. Ion Beam Pulse Interaction with Background Plasma in a Solenoidal Magnetic Field

    CERN Document Server

    Kaganovich, Igor D; Startsev, Edward

    2005-01-01

    Background plasma can be used as an effective neutralization scheme to transport and compress intense ion beam pulses, and the application of a solenoidal magnetic field allows additional control and focusing of the beam pulse. Ion beam pulse propagation in a background plasma immersed in an applied solenoidal magnetic field has been studied both analytically and numerically with three different particle-in-cell codes (LSP, OOPIC-Pro and EDPIC) to cross-check the validity of the results. Very good charge and current neutralization is observed for high values of the solenoidal magnetic field.* However, for intermediate values of the solenoidal magnetic field, current neutralization is a complex process, and a sizable self-magnetic field is generated at the head of the beam. Collective wave excitations are also generated ahead of the beam pulse.

  20. Bunker probe: A plasma potential probe almost insensitive to its orientation with the magnetic field.

    Science.gov (United States)

    Costea, S; Fonda, B; Kovačič, J; Gyergyek, T; Schneider, B S; Schrittwieser, R; Ionita, C

    2016-05-01

    Due to their ability to suppress a large part of the electron current and thus measuring directly the plasma potential, ion sensitive probes have begun to be widely tested and used in fusion devices. For these probes to work, almost perfect alignment with the total magnetic field is necessary. This condition cannot always be fulfilled due to the curvature of magnetic fields, complex magnetic structure, or magnetic field reconnection. In this perspective, we have developed a plasma potential probe (named Bunker probe) based on the principle of the ion sensitive probe but almost insensitive to its orientation with the total magnetic field. Therefore it can be used to measure the plasma potential inside fusion devices, especially in regions with complex magnetic field topology. Experimental results are presented and compared with Ball-Pen probe measurements taken under identical conditions. We have observed that the floating potential of the Bunker probe is indeed little affected by its orientation with the magnetic field for angles ranging from 90° to 30°, in contrast to the Ball-Pen probe whose floating potential decreases towards that of a Langmuir probe if not properly aligned with the magnetic field.

  1. Influence of the magnetic field configuration on the plasma flow in Hall thrusters

    Science.gov (United States)

    Andreussi, T.; Giannetti, V.; Leporini, A.; Saravia, M. M.; Andrenucci, M.

    2018-01-01

    In Hall propulsion, the thrust is provided by the acceleration of ions in a plasma generated in a cross-field configuration. Standard thruster configurations have annular channels with an almost radial magnetic field at the channel exit. A potential difference is imposed in the axial direction and the intensity of the magnetic field is calibrated in order to hinder the electron motion, while leaving the ions non-magnetised. Magnetic field lines can be assumed, as a first approximation, as lines of constant electron temperature and of thermalized potential. In typical thruster configurations, the discharge occurs inside a ceramic channel and, due to plasma–wall interactions, the electron temperature is typically low, less than few tens of eV. Hence, the magnetic field lines can be effectively used to tailor the distribution of the electrostatic potential. However, the erosion of the ceramic walls caused by the ion bombardment represents the main limiting factor of the thruster lifetime and new thruster configurations are currently under development. For these configurations, classical first order models of the plasma dynamics fail to grasp the influence of the magnetic topology on the plasma flow. In the present paper, a novel approach to investigate the correlation between magnetic field topology and thruster performance is presented. Due to the anisotropy induced by the magnetic field, the gradients of the plasma properties are assumed to be mainly in the direction orthogonal to the local magnetic field, thus enabling a quasi-one-dimensional description in magnetic coordinates. Theoretical and experimental investigations performed on a 5 kW class Hall thruster with different magnetic field configurations are then presented and discussed.

  2. Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization.

    Science.gov (United States)

    Zhang, H-S; Komvopoulos, K

    2008-07-01

    Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp3) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study.

  3. Magnetic field influence on aurorae and the Jovian plasma disk radial structure

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2006-05-01

    Full Text Available The Jovian paraboloid magnetospheric model is applied for the investigation of the planet's auroral emission and plasma disk structure in the middle magnetosphere. Jupiter's auroral emission demonstrates the electrodynamic coupling between the ionosphere and magnetosphere. For comparison of different regions in the ionospheric level and in the magnetosphere, the paraboloid model of the global magnetospheric magnetic field is used. This model provides mapping along highly-conducting magnetic field lines. The paraboloid magnetic field model is also applied for consideration of the stability of the background plasma disk in the rotating Jupiter magnetosphere with respect to the flute perturbations. Model radial distribution of the magnetic field and experimental data on the plasma angular velocity in the middle Jovian magnetosphere are used. A dispersion relation of the plasma perturbations in the case of a perfectly conducting ionosphere is obtained. Analyzing starting conditions of a flute instability in the disk, the "threshold" radial profile of the plasma density is determined. An application of the results obtained to the known data on the Jovian plasma disk is discussed.

  4. The impact of Hall physics on magnetized high energy density plasma jets

    Science.gov (United States)

    Gourdain, Pierre-Alexandre

    2013-10-01

    Magnetized high energy density (HED) plasma jets produced by radial foil explosions on pulsed power machines have improved our understanding of the fundamental mechanisms driving flowing matter under extreme conditions. Experiments and simulations indicate that magnetic fields are crucial in the formation and stability of strongly collimated plasma jets, a property also shared by astrophysical jets originating from black holes and protostars. It is understood that these magnetic fields also generate electric fields, often associated with the dynamo effect. In fact, when the Lundquist number is large enough, the dynamo effect is frequently seen as the dominant electric field driver of flowing plasmas. This is true inside the collimated jet where the density (> 1019 cm-3) , velocity ( 50 eV) are high enough to preclude the dominance of any other type of electric fields. However, the ion flow speed is much lower than the speed of light. As a result, dynamo electric fields do not impact noticeably fluid motion since electric stresses are negligible compared to magnetic stresses. On the other hand, Hall physics dominates the low density plasma surrounding the jet (< 1018 cm-3) . In this region, electron speeds can be orders of magnitude higher than the bulk flow velocity as ion and electron fluids are decoupled. As a result, electric stresses can rival with magnetic stresses and Hall physics does impact the overall plasma dynamics. This talk will discuss how HED plasmas are subjected to Hall physics and how it impacts the particle confinement as well as the MHD stability of plasma jets. After focusing on experimental results and numerical simulations from the PERSEUS code, the talk will extend its conclusions to inertial fusion regimes where Hall physics could also alter plasma confinement and stability. Research supported by NNSA/DOE Grant Cooperative Agreements DE-FC52-06NA 00057, DE-NA 0001836 and NSF Grant PHY-1102471.

  5. The Plasma Instrument for Magnetic Sounding (PIMS) on The Europa Clipper Mission

    Science.gov (United States)

    Westlake, Joseph H.; McNutt, Ralph L.; Kasper, Justin C.; Case, Anthony W.; Grey, Matthew P.; Kim, Cindy K.; Battista, Corina C.; Rymer, Abigail; Paty, Carol S.; Jia, Xianzhe; Stevens, Michael L.; Khurana, Krishan; Kivelson, Margaret G.; Slavin, James A.; Korth, Haje H.; Smith, Howard T.; Krupp, Norbert; Roussos, Elias; Saur, Joachim

    2016-10-01

    The Europa Clipper mission is equipped with a sophisticated suite of 9 instruments to study Europa's interior and ocean, geology, chemistry, and habitability from a Jupiter orbiting spacecraft. The Plasma Instrument for Magnetic Sounding (PIMS) on Europa Clipper is a Faraday Cup based plasma instrument whose heritage dates back to the Voyager spacecraft. PIMS will measure the plasma that populates Jupiter's magnetosphere and Europa's ionosphere. The science goals of PIMS are to: 1) estimate the ocean salinity and thickness by determining Europa's magnetic induction response, corrected for plasma contributions; 2) assess mechanisms responsible for weathering and releasing material from Europa's surface into the atmosphere and ionosphere; and 3) understand how Europa influences its local space environment and Jupiter's magnetosphere and vice versa.Europa is embedded in a complex Jovian magnetospheric plasma, which rotates with the tilted planetary field and interacts dynamically with Europa's ionosphere affecting the magnetic induction signal. Plasma from Io's temporally varying torus diffuses outward and mixes with the charged particles in Europa's own torus producing highly variable plasma conditions at Europa. PIMS works in conjunction with the Interior Characterization of Europa using Magnetometry (ICEMAG) investigation to probe Europa's subsurface ocean. This investigation exploits currents induced in Europa's interior by the moon's exposure to variable magnetic fields in the Jovian system to infer properties of Europa's subsurface ocean such as its depth, thickness, and conductivity. This technique was successfully applied to Galileo observations and demonstrated that Europa indeed has a subsurface ocean. While these Galileo observations contributed to the renewed interest in Europa, due to limitations in the observations the results raised major questions that remain unanswered. PIMS will greatly refine our understanding of Europa's global liquid ocean by

  6. On the Role of Dust Particles in Decoupling of Plasma from Magnetic Field in Laboratory and Space

    OpenAIRE

    Rudakov, L. I.; Gretchikha, A. V.; liu, C. S.; Milikh, G. M.

    2000-01-01

    The objective of this paper is to apply the recent achievements in understanding of the non-MHD effects in plasma (acquired both in laboratory experiments, as well as in theory), to the interstellar phenomena. Applied to the space plasma, these effects can significantly change the picture of plasma dynamics. Charged dust particles are always present in the interstellar medium and can easily remain not magnetized, even when the plasma electrons and ions are strongly magnetized. In such a mediu...

  7. Formation of current filaments and magnetic field generation in a quantum current-carrying plasma

    Science.gov (United States)

    Niknam, A. R.; Taghadosi, M. R.; Majedi, S.; Khorashadizadeh, S. M.

    2013-09-01

    The nonlinear dynamics of filamentation instability and magnetic field in a current-carrying plasma is investigated in the presence of quantum effects using the quantum hydrodynamic model. A new nonlinear partial differential equation is obtained for the spatiotemporal evolution of the magnetic field in the diffusion regime. This equation is solved by applying the Adomian decomposition method, and then the profiles of magnetic field and electron density are plotted. It is shown that the saturation time of filamentation instability increases and, consequently, the instability growth rate and the magnetic field amplitude decrease in the presence of quantum effects.

  8. Non-modal stability analysis and transient growth in a magnetized Vlasov plasma

    KAUST Repository

    Ratushnaya, V.

    2014-12-01

    Collisionless plasmas, such as those encountered in tokamaks, exhibit a rich variety of instabilities. The physical origin, triggering mechanisms and fundamental understanding of many plasma instabilities, however, are still open problems. We investigate the stability properties of a 3-dimensional collisionless Vlasov plasma in a stationary homogeneous magnetic field. We narrow the scope of our investigation to the case of Maxwellian plasma and examine its evolution with an electrostatic approximation. For the first time using a fully kinetic approach we show the emergence of the local instability, a transient growth, followed by classical Landau damping in a stable magnetized plasma. We show that the linearized Vlasov operator is non-normal leading to the algebraic growth of the perturbations using non-modal stability theory. The typical time scales of the obtained instabilities are of the order of several plasma periods. The first-order distribution function and the corresponding electric field are calculated and the dependence on the magnetic field and perturbation parameters is studied. Our results offer a new scenario of the emergence and development of plasma instabilities on the kinetic scale.

  9. Dynamic Response of a Magnetized Plasma to AN External Source: Application to Space and Solid State Plasmas

    Science.gov (United States)

    Zhou, Huai-Bei

    This dissertation examines the dynamic response of a magnetoplasma to an external time-dependent current source. To achieve this goal a new method which combines analytic and numerical techniques to study the dynamic response of a 3-D magnetoplasma to a time-dependent current source imposed across the magnetic field was developed. The set of the cold electron and/or ion plasma equations and Maxwell's equations are first solved analytically in (k, omega)^ace; inverse Laplace and 3 -D complex Fast Fourier Transform (FFT) techniques are subsequently used to numerically transform the radiation fields and plasma currents from the (k, omega) ^ace to the (r, t) space. The dynamic responses of the electron plasma and of the compensated two-component plasma to external current sources are studied separately. The results show that the electron plasma responds to a time -varying current source imposed across the magnetic field by exciting whistler/helicon waves and forming of an expanding local current loop, induced by field aligned plasma currents. The current loop consists of two anti-parallel field-aligned current channels concentrated at the ends of the imposed current and a cross-field current region connecting these channels. The latter is driven by an electron Hall drift. A compensated two-component plasma responds to the same current source as following: (a) For slow time scales tau > Omega_sp{i}{-1} , it generates Alfven waves and forms a non-local current loop in which the ion polarization currents dominate the cross-field current; (b) For fast time scales tau emf inducing tethered satellite systems (TSS), generation of ELF/VLF waves by ionospheric heating, current closure and quasineutrality in thin magnetopause transitions, and short electromagnetic pulse generation in solid state plasmas. The cross-field current in TSS builds up on a time scale corresponding to the whistler waves and results in local current closure. Amplitude modulated HF ionospheric heating

  10. Understanding plasma facing surfaces in magnetic fusion devices

    Science.gov (United States)

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

    2013-09-01

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

  11. Parametric instabilities in shallow water magnetohydrodynamics of astrophysical plasma in external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Klimachkov, D.A., E-mail: klimachkovdmitry@gmail.com [Space Research Institute of Russian Academy of Science, 84/32, Profsoyuznaya str., Moscow, 117997 (Russian Federation); Petrosyan, A.S. [Space Research Institute of Russian Academy of Science, 84/32, Profsoyuznaya str., Moscow, 117997 (Russian Federation); Moscow Institute of Physics and Technology (State University), 9 Institutskyi per., Dolgoprudny, Moscow Region, 141700 (Russian Federation)

    2017-01-15

    This article deals with magnetohydrodynamic (MHD) flows of a thin rotating layer of astrophysical plasma in external magnetic field. We use the shallow water approximation to describe thin rotating plasma layer with a free surface in a vertical external magnetic field. The MHD shallow water equations with external vertical magnetic field are revised by supplementing them with the equations that are consequences of the magnetic field divergence-free conditions and reveal the existence of third component of the magnetic field in such approximation providing its relation with the horizontal magnetic field. It is shown that the presence of a vertical magnetic field significantly changes the dynamics of the wave processes in astrophysical plasma compared to the neutral fluid and plasma layer in a toroidal magnetic field. The equations for the nonlinear wave packets interactions are derived using the asymptotic multiscale method. The equations for three magneto-Poincare waves interactions, for three magnetostrophic waves interactions, for the interactions of two magneto-Poincare waves and for one magnetostrophic wave and two magnetostrophic wave and one magneto-Poincare wave interactions are obtained. The existence of parametric decay and parametric amplifications is predicted. We found following four types of parametric decay instabilities: magneto-Poincare wave decays into two magneto-Poincare waves, magnetostrophic wave decays into two magnetostrophic waves, magneto-Poincare wave decays into one magneto-Poincare wave and one magnetostrophic wave, magnetostrophic wave decays into one magnetostrophic wave and one magneto-Poincare wave. Following mechanisms of parametric amplifications are found: parametric amplification of magneto-Poincare waves, parametric amplification of magnetostrophic waves, magneto-Poincare wave amplification in magnetostrophic wave presence and magnetostrophic wave amplification in magneto-Poincare wave presence. The instabilities growth rates

  12. Experimental Investigation of Active Feedback Control of Turbulent Transport in a Magnetized Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Mark Allen [University of New Mexico

    2013-07-07

    A new and unique basic plasma science laboratory device - the HelCat device (HELicon-CAThode) - has been constructed and is operating at the University of New Mexico. HelCat is a 4 m long, 0.5 m diameter device, with magnetic field up to 2.2 kG, that has two independent plasmas sources - an RF helicon source, and a thermionic cathode. These two sources, which can operate independently or simultaneously, are capable of producing plasmas with a wide range of parameters and turbulence characteristics, well suited to a variety of basic plasma physics experiments. An extensive set of plasma diagnostics is also operating. Experiments investigating the active feedback control of turbulent transport of particles and heat via electrode biasing to affect plasma ExB flows are underway, and ongoing.

  13. Plasma electron observations in the vicinity of magnetic holes

    Science.gov (United States)

    King, J. H.; Ogilvie, K. W.; Behannon, K. W.

    1979-01-01

    In the present study, 14 events of interplanetary magnetic field dips are identified. Eleven of these are found to be associated with significant enhancements in the flux of electrons of energies of approximately 100 eV. Five (of the eleven) are characterized by significant changes in the magnetic field direction, and six are not. Thus, even though an electron enhancement is usually seen at a dip, the enhancement need not be always associated with magnetic reconnection, for which a directional change is essential. It appears that some events involve local acceleration, possibly the results of reconnection, while others may involve electrons injected onto the field line at a remote point.

  14. Observations and modeling of magnetized plasma jets and bubbles launched into a transverse B-field

    Science.gov (United States)

    Fisher, Dustin M.; Zhang, Yue; Wallace, Ben; Gilmore, Mark; Manchester, Ward B., IV; van der Holst, Bart; Rogers, Barrett N.; Hsu, Scott C.

    2017-10-01

    Hot, dense, plasma structures launched from a coaxial plasma gun on the HelCat dual-source plasma device at the University of New Mexico drag frozen-in magnetic flux into the chamber's background magnetic field providing a rich set of dynamics to study magnetic turbulence, force-free magnetic spheromaks, shocks, as well as CME-like dynamics possibly relevant to the solar corona. Vector magnetic field data from an eleven-tipped B-dot rake probe and images from an ultra-fast camera will be presented in comparison with ongoing MHD modeling using the 3-D MHD BATS-R-US code developed at the University of Michigan. BATS-R-US employs an adaptive mesh refinement grid (AMR) that enables the capture and resolution of shock structures and current sheets and is uniquely suited for flux-rope expansion modeling. Recent experiments show a possible magnetic Rayleigh-Taylor (MRT) instability that appears asymmetrically at the interface between launched spheromaks (bubbles) and their entraining background magnetic field. Efforts to understand this instability using in situ measurements, new chamber boundary conditions, and ultra-fast camera data will be presented. Work supported by the Army Research Office Award No. W911NF1510480.

  15. Transport properties of interacting magnetic islands in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Gianakon, T.A.; Callen, J.D.; Hegna, C.C.

    1993-10-01

    This paper explores the equilibrium and transient transport properties of a mixed magnetic topology model for tokamak equilibria. The magnetic topology is composed of a discrete set of mostly non-overlapping magnetic islands centered on the low-order rational surfaces. Transport across the island regions is fast due to parallel transport along the stochastic magnetic field lines about the separatrix of each island. Transport between island regions is assumed to be slow due to a low residual cross-field transport. In equilibrium, such a model leads to: a nonlinear dependence of the heat flux on the pressure gradient; a power balance diffusion coefficient which increases from core to edge; and profile resiliency. Transiently, such a model also exhibits a heat pulse diffusion coefficient larger than the power balance diffusion coefficient.

  16. Magnetic Alfvén-Cyclotron Fluctuations of Anisotropic Non-Thermal Plasmas

    Science.gov (United States)

    Navarro, R.; Munoz, V.; Araneda, J. A.; Vinas, A. F.; Moya, P. S.; Valdivia, J. A.

    2014-12-01

    Remote and in situ observations in the solar wind show that ion and electron velocity distributions persistently present deviations from thermal equilibrium. Ion anisotropies seem to be constrained by instability thresholds which are in agreement with linear kinetic theory. For plasma states below these instability thresholds, the quasi-stable solar wind plasma sustains a small but detectable level of magnetic fluctuation power. These fluctuations may be related to spontaneous electromagnetic fluctuations arising from the discreteness of charged particles. Here, we study electromagnetic fluctuations propagating along a background magnetic field in a plasma composed of thermal and suprathermal protons and electrons via the fluctuation-dissipation theorem. The total fluctuating magnetic power is estimated in a proton temperature anisotropy-beta diagram for three different families of proton distribution functions, which can be compared to a number of recent measurements in the solar wind.

  17. Simultaneous Measurements of Electrostatic and Magnetic Fluctuations in ASDEX Upgrade Edge Plasma

    DEFF Research Database (Denmark)

    Ionita, Codrina; Vianello, Nicola; Müller, H.W.

    2009-01-01

    In ASDEX Upgrade (AUG) electrostatic and magnetic fluctuations in the edge plasma region were measured simultaneously during ELMy H-mode (high confinement) plasmas and L-mode (low confinement) plasmas and during a transition between the two modes. A special probe was used containing six Langmuir...... probe pins of graphite of which one is protruding radially. In addition, 20 mm behind the front side a triple magnetic pick-up coil is mounted inside the probe head by which temporal variations of the magnetic field in all three directions of space can be detected. The probe pins are arranged...... in such a way that simultaneously the poloidal and radial electric field components, the ion saturation current and the current-voltage characteristic can be registered. During the AUG discharges of 7 s lengths the probe head is inserted two to three times for 100 ms each by the midplane manipulator...

  18. Magnetic flux pile-up and ion heating in a current sheet formed by colliding magnetized plasma flows

    Science.gov (United States)

    Suttle, L.; Hare, J.; Lebedev, S.; Ciardi, A.; Loureiro, N.; Niasse, N.; Burdiak, G.; Clayson, T.; Lane, T.; Robinson, T.; Smith, R.; Stuart, N.; Suzuki-Vidal, F.

    2017-10-01

    We present data from experiments carried out at the Magpie pulsed power facility, which show the detailed structure of the interaction of counter-streaming magnetized plasma flows. In our quasi-2D setup, continuous supersonic flows are produced with strong embedded magnetic fields of opposing directions. Their interaction leads to the formation of a dense and long-lasting current sheet, where we observe the pile-up of the magnetic flux at the sheet boundary, as well as the annihilation of field inside, accompanied by an increase in plasma temperature. Spatially resolved measurements with Faraday rotation polarimetry, B-dot probes, XUV imaging, Thomson scattering and laser interferometry diagnostics show the detailed distribution of the magnetic field and other plasma parameters throughout the system. This work was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) Grant No. EP/G001324/1, and by the U.S. Department of Energy (DOE) Awards No. DE-F03-02NA00057 and No. DE-SC-0001063.

  19. Analysis of Electromagnetic Wave Propagation in a Magnetized Re-Entry Plasma Sheath Via the Kinetic Equation

    Science.gov (United States)

    Manning, Robert M.

    2009-01-01

    Based on a theoretical model of the propagation of electromagnetic waves through a hypersonically induced plasma, it has been demonstrated that the classical radiofrequency communications blackout that is experienced during atmospheric reentry can be mitigated through the appropriate control of an external magnetic field of nominal magnitude. The model is based on the kinetic equation treatment of Vlasov and involves an analytical solution for the electric and magnetic fields within the plasma allowing for a description of the attendant transmission, reflection and absorption coefficients. The ability to transmit through the magnetized plasma is due to the magnetic windows that are created within the plasma via the well-known whistler modes of propagation. The case of 2 GHz transmission through a re-entry plasma is considered. The coefficients are found to be highly sensitive to the prevailing electron density and will thus require a dynamic control mechanism to vary the magnetic field as the plasma evolves through the re-entry phase.

  20. Two Stream Instability in Magnetized Warm Plasma under the Ionization Effect

    Science.gov (United States)

    Jyoti, -; Malik, Hitendra K.

    2012-10-01

    Two - stream instability is considered in the presence of magnetic field in inhomogeneous plasma. The continuity and the momentum equation which take into account the ionization constant are formulated for ions and the electrons including the effect of finite temperature of ions along with the ionization effect. Using normal mode analysis along with linear approximation, potential is found from Poisson's equation neglecting higher order perturbed terms. The behavior of growth rate with magnetic field and the propagation angle along with ionization constant has been studied with different plasma oscillation wavelength to Debye length ratio for both the laboratory as well as the space plasma parameters. We observe two types of instability in both the cases. In case of laboratory plasma one of the instability is growing at larger plasma oscillation wavelength and another one at lower wavelength while in the case of space plasma both the instabilities grow only at smaller plasma oscillation wavelength but with different growth rates. All the instabilities has higher growth rate at smaller wave length of oscillations. Effect of finite ion temperature is studied with respect to different electron temperature both in the laboratory as well as in space plasma.

  1. MM-wave emission by magnetized plasma during sub-relativistic electron beam relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, I. A., E-mail: Ivanov@inp.nsk.su; Arzhannikov, A. V.; Burmasov, V. S.; Popov, S. S.; Postupaev, V. V.; Sklyarov, V. F.; Vyacheslavov, L. N. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090 (Russian Federation); Burdakov, A. V.; Sorokina, N. V. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, 20 Karl Marx Avenue, Novosibirsk 630092 (Russian Federation); Gavrilenko, D. E.; Kasatov, A. A.; Kandaurov, I. V.; Mekler, K. I.; Rovenskikh, A. F.; Trunev, Yu. A. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, Novosibirsk 630090 (Russian Federation); Kurkuchekov, V. V.; Kuznetsov, S. A. [Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090 (Russian Federation); Polosatkin, S. V. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, 20 Karl Marx Avenue, Novosibirsk 630092 (Russian Federation)

    2015-12-15

    There are described electromagnetic spectra of radiation emitted by magnetized plasma during sub-relativistic electron beam in a double plasma frequency band. Experimental studies were performed at the multiple-mirror trap GOL-3. The electron beam had the following parameters: 70–110 keV for the electron energy, 1–10 MW for the beam power and 30–300 μs for its duration. The spectrum was measured in 75–230 GHz frequency band. The frequency of the emission follows variations in electron plasma density and magnetic field strength. The specific emission power on the length of the plasma column is estimated on the level 0.75 kW/cm.

  2. Influence of an axial magnetic field on the density profile of capillary plasma channels

    CERN Document Server

    Ivanov, V V; Toma, E S; Bijkerk, F

    2003-01-01

    A narrow capillary plasma channel, with a sizeable depletion of the electron density on the channel axis, has been proposed to guide a laser pulse over a length of several to several tens of centimetres. We discuss the possibility to significantly improve the wave-guiding properties of such a channel by applying an axial magnetic field. Our analytical and numerical studies show that a pulsed axial magnetic field of 10 T in a hydrogen capillary plasma at a pressure of 50 Torr will reduce the on-axis plasma density by a factor of three, and the full width at half maximum of the density profile by a factor of two. The resulting parabolic plasma density profile is expected to be more efficient in guiding laser pulses.

  3. Correlation Between the Magnetic Field and Plasma Parameters at 1 AU

    Science.gov (United States)

    Yang, Zicai; Shen, Fang; Zhang, Jie; Yang, Yi; Feng, Xueshang; Richardson, Ian G.

    2018-02-01

    The physical parameters of the solar wind observed in-situ near 1 AU have been studied for several decades, and relationships between them, such as the positive correlation between the solar wind plasma temperature, T, and velocity, V, and the negative correlation between density, N, and velocity, V, are well known. However, the magnetic field intensity, B, does not appear to be well correlated with any individual plasma parameter. In this article, we discuss previously under-reported correlations between B and the combined plasma parameters √{N V2} as well as between B and √{NT}. These two correlations are strong during periods of corotating interaction regions and high-speed streams, and moderate during intervals of slow solar wind. The results indicate that the magnetic pressure in the solar wind is well correlated both with the plasma dynamic pressure and the thermal pressure.

  4. Excitation of kinetic Alfven waves by resonant mode conversion and longitudinal heating of magnetized plasmas

    Science.gov (United States)

    Tanaka, Motohiko; Sato, Tetsuya; Hasegawa, A.

    1989-01-01

    The excitation of the kinetic Alfven wave by resonant mode conversion and longitudinal heating of the plasma by the kinetic Alfven wave were demonstrated on the basis of a macroscale particle simulation. The longitudinal electron current was shown to be cancelled by the ions. The kinetic Alfven wave produced an ordered motion of the plasma particles in the wave propagation direction. The electrons were pushed forward along the ambient magnetic field by absorbing the kinetic Alfven wave through the Landau resonance.

  5. Geometric Phase Of The Faraday Rotation Of Electromagnetic Waves In Magnetized Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jian Liu and Hong Qin

    2011-11-07

    The geometric phase of circularly polarized electromagnetic waves in nonuniform magnetized plasmas is studied theoretically. The variation of the propagation direction of circularly polarized waves results in a geometric phase, which also contributes to the Faraday rotation, in addition to the standard dynamical phase. The origin and properties of the geometric phase is investigated. The in uence of the geometric phase to plasma diagnostics using Faraday rotation is also discussed as an application of the theory.

  6. Optical carriage for laser-induced fluorescence in a magnetized plasma

    Science.gov (United States)

    Anderegg, F.; Paris, P. J.; Skiff, F.; Good, T. N.; Tran, M. Q.

    1988-10-01

    An ``optical carriage'' has been developed to improve plasma access for LIF diagnostics. Laser light inducing the fluorescence is transported through an optical fiber to the carriage. A telescope fixed on the carriage collects the plasma fluorescence light and sends it through a fiber bundle to an external PMT. The whole carriage is mounted on rails and can be scanned along and across the magnetic field.

  7. Rotating structures in low temperature magnetized plasmas - Insight from particle simulations

    Directory of Open Access Journals (Sweden)

    Jean-Pierre eBoeuf

    2014-12-01

    Full Text Available The EXB configuration of various low temperature plasma devices is often responsible for the formation of rotating structures and instabilities leading to anomalous electron transport across the magnetic field. In these devices, electrons are strongly magnetized while ions are weakly or not magnetized and this leads to specific physical phenomena that are not present in fusion plasmas where both electrons and ions are strongly magnetized. In this paper we describe basic phenomena involving rotating plasma structures in simple configurations of low temperature EXB plasma devices on the basis of PIC-MCC (Particle-In-Cell Monte Carlo Collisions simulations. We focus on three examples: rotating electron vortices and rotating spokes in cylindrical magnetrons, and azimuthal electron-cyclotron drift instability in Hall thrusters. The simulations are not intended to give definite answers to the many physics issues related to low temperature EXB plasma devices but are used to illustrate and discuss some of the basic questions that need further studies.

  8. Soliton reflection in a magnetized inhomogeneous warm plasma: effect of ionization

    Science.gov (United States)

    Malik, Hitendra K.; Jyoti; Kumar, Ravinder

    2014-04-01

    The reflection of nonlinear solitary waves is studied in a plasma under the effect of an external magnetic field and constant ionization along with finite ion temperature. To investigate the reflection of solitary waves, relevant modified Korteweg-deVries equations for the right and left going waves are derived, and coupled at the point of reflection for obtaining the expression of reflection coefficient. The solitary waves are found to shift after their reflection. Variation of reflection coefficient and shift are studied for different plasma parameters like ion temperature, ionization rate and wave propagation angle or the obliqueness of magnetic field.

  9. The distant bow shock and magnetotail of Venus - Magnetic field and plasma wave observations

    Science.gov (United States)

    Russell, C. T.; Luhmann, J. G.; Elphic, R. C.; Scarf, F. L.

    1981-01-01

    An examination of the magnetic field and plasma wave data obtained by the Pioneer Venus orbiter in the wake region behind Venus discloses a well developed bow shock whose location is similar to that observed on previous missions in contrast to the dayside bow shock. Venus also has a well developed magnetotail in which the field strenght is enhanced over magnetosheath values and in which the magnetic field is aligned approximately with the solar wind direction. The boundary between magnetosheath and magnetotail is also marked by a change in the plasma wave spectrum.

  10. Espisodic detachment of Martian crustal magnetic fields leading to bulk atmospheric plasma escape

    Energy Technology Data Exchange (ETDEWEB)

    Brain, D A; Baker, A H; Briggs, J; Eastwood, J P; Halekas, J S; Phan, T

    2009-06-02

    We present an analysis of magnetic field and suprathermal electron measurements from the Mars Global Surveyor (MGS) spacecraft that reveals isolated magnetic structures filled with Martian atmospheric plasma located downstream from strong crustal magnetic fields with respect to the flowing solar wind. The structures are characterized by magnetic field enhancements and rotations characteristic of magnetic flux ropes, and characteristic ionospheric electron energy distributions with angular distributions distinct from surrounding regions. These observations indicate that significant amounts of atmosphere are intermittently being carried away from Mars by a bulk removal process: the top portions of crustal field loops are stretched through interaction with the solar wind and detach via magnetic reconnection. This process occurs frequently and may account for as much as 10% of the total present-day ion escape from Mars.

  11. Standing helicon induced by a rapidly bent magnetic field in plasmas

    Science.gov (United States)

    Takahashi, Kazunori; Takayama, Sho; Komuro, Atsushi; Ando, Akira; Plasma physics Team

    2016-09-01

    An electron energy probability function and an rf magnetic field are measured in an rf hydrogen helicon source, where axial and transverse static magnetic fields are applied to the source by solenoids and to the diffusion chamber by filter magnets, respectively. It is demonstrated that the helicon wave is reflected by the rapidly bent magnetic field and the resultant standing wave heats the electrons between the source and the magnetic filter, while the electron cooling effect by the magnetic filter is maintained. It is interpreted that the standing wave is generated by the presence of spatially localized change of a refractive index. The application to the hydrogen negative ion source used for the neutral beam injection system for fusion plasma heating is discussed. This work is partially supported by grant-in-aid for scientific research (16H04084 and 26247096) from the Japan Society for the Promotion of Science.

  12. On the ions acceleration via collisionless magnetic reconnection in laboratory plasmas

    CERN Document Server

    Cazzola, Emanuele; Markidis, Stefano; Lapenta, Giovanni

    2016-01-01

    This work presents an analysis of the ion outflow from magnetic reconnection throughout fully kinetic simulations with typical laboratory plasmas values. A symmetric initial configuration for the density and magnetic field is considered across the current sheet. After analyzing the behavior of a set of nine simulations with a reduced mass ratio and with a permuted value of three initial electron temperature and magnetic field intensity, the best ion acceleration scenario is further studied with a realistic mass ratio in terms of the ion dynamics and energy budget. Interestingly, a series of shock waves structures are observed in the outflow, resembling the shock discontinuities found in recent magnetohydrodynamic (MHD) simulations. An analysis of the ion outflow at several distances from the reconnection point is presented, in light of possible laboratory applications. The analysis suggests that magnetic reconnection could be used as a tool for plasma acceleration, with applications ranging from electric prop...

  13. Observation of turbulent intermittency scaling with magnetic helicity in an MHD plasma wind tunnel.

    Science.gov (United States)

    Schaffner, D A; Wan, A; Brown, M R

    2014-04-25

    The intermittency in turbulent magnetic field fluctuations has been observed to scale with the amount of magnetic helicity injected into a laboratory plasma. An unstable spheromak injected into the MHD wind tunnel of the Swarthmore Spheromak Experiment displays turbulent magnetic and plasma fluctuations as it relaxes into a Taylor state. The level of intermittency of this turbulence is determined by finding the flatness of the probability distribution function of increments for magnetic pickup coil fluctuations B˙(t). The intermittency increases with the injected helicity, but spectral indices are unaffected by this variation. While evidence is provided which supports the hypothesis that current sheets and reconnection sites are related to the generation of this intermittent signal, the true nature of the observed intermittency remains unknown.

  14. Effects of a static inhomogeneous magnetic field acting on a laser-produced carbon plasma plume

    Directory of Open Access Journals (Sweden)

    M. Favre

    2017-08-01

    Full Text Available We present time- and space-resolved observations of the dynamics of a laser-produced carbon plasma, propagating in a sub-Tesla inhomogeneous magnetic field, with both, axial and radial field gradients. An Nd:YAG laser pulse, 340 mJ, 3.5 ns, at 1.06 μm, with a fluence of 7 J/cm2, is used to generate the plasma from a solid graphite target, in vacuum. The magnetic field is produced using two coaxial sets of two NeFeB ring magnets, parallel to the laser target surface. The diagnostics include plasma imaging with 50 ns time resolution, spatially resolved optical emission spectroscopy and Faraday cup. Based on our observations, evidence of radial and axial plasma confinement due to magnetic field gradients is presented. Formation of C2 molecules, previously observed in the presence of a low pressure neutral gas background, and enhanced on-axis ion flux, are ascribed to finite Larmor radius effects and reduced radial transport due to the presence of the magnetic field.

  15. Shear flow effect on ion temperature gradient vortices in plasmas with sheared magnetic field

    DEFF Research Database (Denmark)

    Chakrabarti, N.; Juul Rasmussen, J.

    1999-01-01

    The effect of velocity shear on ion temperature gradient (ITG) driven vortices in a nonuniform plasma in a curved, sheared magnetic field is investigated. In absence of parallel ion dynamics, vortex solutions for the ITG mode are studied analytically. It is shown that under certain conditions...... and ultimately lead to a dominating monopolar form. The effects of magnetic shear indicate it may destroy these structures. (C) 1999 American Institute of Physics....

  16. Magnetospheric Multiscale Observations of Electron Vortex Magnetic Hole in the Turbulent Magnetosheath Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Huang, S. Y.; Yuan, Z. G.; Wang, D. D.; Yu, X. D. [School of Electronic Information, Wuhan University, Wuhan (China); Sahraoui, F.; Contel, O. Le [Laboratoire de Physique des Plasmas, CNRS-Ecole Polytechnique-UPMC, Palaiseau (France); He, J. S. [School of Earth and Space Sciences, Peking University, Beijing (China); Zhao, J. S. [Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing (China); Deng, X. H.; Pang, Y.; Li, H. M. [Institute of Space Science and Technology, Nanchang University, Nanchang (China); Zhou, M. [Department of Physics and Astronomy, University of California, Los Angeles, CA (United States); Fu, H. S.; Yang, J. [School of Space and Environment, Beihang University, Beijing (China); Shi, Q. Q. [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai (China); Lavraud, B. [Institut de Recherche and Astrophysique et Planétologie, Université de Toulouse (UPS), Toulouse (France); Pollock, C. J.; Giles, B. L. [NASA, Goddard Space Flight Center, Greenbelt, MD (United States); Torbert, R. B. [University of New Hampshire, Durham, NH (United States); Russell, C. T., E-mail: shiyonghuang@whu.edu.cn [Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA (United States); and others

    2017-02-20

    We report on the observations of an electron vortex magnetic hole corresponding to a new type of coherent structure in the turbulent magnetosheath plasma using the Magnetospheric Multiscale mission data. The magnetic hole is characterized by a magnetic depression, a density peak, a total electron temperature increase (with a parallel temperature decrease but a perpendicular temperature increase), and strong currents carried by the electrons. The current has a dip in the core region and a peak in the outer region of the magnetic hole. The estimated size of the magnetic hole is about 0.23 ρ {sub i} (∼30 ρ {sub e}) in the quasi-circular cross-section perpendicular to its axis, where ρ {sub i} and ρ {sub e} are respectively the proton and electron gyroradius. There are no clear enhancements seen in high-energy electron fluxes. However, there is an enhancement in the perpendicular electron fluxes at 90° pitch angle inside the magnetic hole, implying that the electrons are trapped within it. The variations of the electron velocity components V {sub em} and V {sub en} suggest that an electron vortex is formed by trapping electrons inside the magnetic hole in the cross-section in the M – N plane. These observations demonstrate the existence of a new type of coherent structures behaving as an electron vortex magnetic hole in turbulent space plasmas as predicted by recent kinetic simulations.

  17. On equilibria of finite pressure plasma in magnetic multipoles

    Energy Technology Data Exchange (ETDEWEB)

    Krasheninnikov, S. I.; Soboleva, T. K.

    2001-07-01

    Separable solutions of finite plasma pressure equilibrium in a point multipole are found. Using the energy principle it is demonstrated that these solutions are interchange stable for quadripole and sextipole configurations. The low and high pressure forms of the solution in sextipole configuration are explicitly displayed.

  18. Hybrid simulations of plasma transport by Kelvin-Helmholtz instability at the magnetopause: magnetic shear

    Energy Technology Data Exchange (ETDEWEB)

    Cowee, Misa M [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Gary, S Peter [Los Alamos National Laboratory

    2009-01-01

    Two-dimensional hybrid (kinetic ions, massless fluid electrons) simulations of the Kelvin Helmholtz Instability (KHI) for a magnetopause configuration with a magnetic shear across the boundary are carried out to examine how the transport of magnetosheath plasma into the magnetosphere is affected by the shear field. Low magnetic shear conditions where the magnetosheath magnetic field is within 30{sup o} of northward is included in the simulations because KHI is thought to be important for plasma transport only for northward or near-northward interplanetary magnetic field orientations. The simulations show that coherent vortices can grow for these near-northward angles, and that they are sometimes more coherent than for pure northward conditions because the turbulence which breaks-down these vortices is reduced when there are magnetic tension forces. With increasing magnetic shear angle, the growth rate is reduced, and the vortices do not grow to as large of size which reduces the plasma transport. By tracking the individual particle motions diffusion coefficients can be obtained for the system, where the diffusion is not classical in nature but instead has a time dependence resulting from both the increasingly large-scale vortex motion and the small-scale turbulence generated in the break-down of the instabilities. Results indicate that diffusion on the order of 10{sup 9} m{sup 2}/s could possibly be generated by KHI on the flanks of the magnetosphere.

  19. Transient loss of plasma from a theta pinch having an initially reversed magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Heidrich, J. E.

    1981-01-01

    The results of an experimental study of the transient loss of plasma from a 25-cm-long theta pinch initially containing a reversed trapped magnetic field are presented. The plasma, amenable to MHD analyses, was a doubly ionized helium plasma characterized by an ion density N/sub i/ = 2 x 10/sup 16/ cm/sup -3/ and an ion temperature T/sub i/ = 15 eV at midcoil and by N/sub i/ = 0.5 x 10/sup 16/ cm/sup -3/ and T/sub i/ = 6 eV at a position 2.5 cm beyond the end of the theta coil.

  20. Effect of anisotropic thermal transport on the resistive plasma response to resonant magnetic perturbation field

    Science.gov (United States)

    Bai, Xue; Liu, Yueqiang; Gao, Zhe

    2017-10-01

    Plasma response to the resonant magnetic perturbation (RMP) field is numerically investigated by an extended toroidal fluid model, which includes anisotropic thermal transport physics parallel and perpendicular to the total magnetic field. The thermal transport is found to be effective in eliminating the toroidal average curvature induced plasma screening (the so called Glasser-Green-Johnson, GGJ screening) in a slow toroidal flow regime, whilst having minor effect on modifying the conventional plasma screening regimes at faster flow. This physics effect of interaction between thermal transport and GGJ screening is attributed to the modification of the radial structure of the shielding current, which resulted from the plasma response to the applied field. The modification of the plasma response (shielding current, response field, plasma displacement, and the perturbed velocity) also has direct consequence on the toroidal torques produced by RMP. Modelling results show that thermal transport reduces the resonant electromagnetic torque as well as the torque associated with the Reynolds stress, but enhances the neoclassical toroidal viscous torque at slow plasma flow.

  1. Improved energy confinement with nonlinear isotope effects in magnetically confined plasmas

    CERN Document Server

    Garcia, J; Jenko, F

    2016-01-01

    The efficient production of electricity from nuclear fusion in magnetically confined plasmas relies on a good confinement of the thermal energy. For more than thirty years, the observation that such confinement depends on the mass of the plasma isotope and its interaction with apparently unrelated plasma conditions has remained largely unexplained and it has become one of the main unsolved issues. By means of numerical studies based on the gyrokinetic theory, we quantitatively show how the plasma microturbulence depends on the isotope mass through nonlinear multiscale microturbulence effects involving the interplay between zonal flows, electromagnetic effects and the torque applied. This finding has crucial consequences for the design of future reactors since, in spite of the fact that they will be composed by multiple ion species, their extrapolation from present day experiments heavily relies on the knowledge obtained from a long experimental tradition based in single isotope plasmas.

  2. Driving large magnetic Reynolds number flow in highly ionized, unmagnetized plasmas

    Science.gov (United States)

    Weisberg, D. B.; Peterson, E.; Milhone, J.; Endrizzi, D.; Cooper, C.; Désangles, V.; Khalzov, I.; Siller, R.; Forest, C. B.

    2017-05-01

    Electrically driven, unmagnetized plasma flows have been generated in the Madison plasma dynamo experiment with magnetic Reynolds numbers exceeding the predicted Rmcrit = 200 threshold for flow-driven MHD instability excitation. The plasma flow is driven using ten thermally emissive lanthanum hexaboride cathodes which generate a J ×B torque in helium and argon plasmas. Detailed Mach probe measurements of plasma velocity for two flow topologies are presented: edge-localized drive using the multi-cusp boundary field and volumetric drive using an axial Helmholtz field. Radial velocity profiles show that the edge-driven flow is established via ion viscosity but is limited by a volumetric neutral drag force, and measurements of velocity shear compare favorably to the Braginskii transport theory. Volumetric flow drive is shown to produce larger velocity shear and has the correct flow profile for studying the magnetorotational instability.

  3. A study of the propagation of ulf electromagnetic fields in collisional, inhomogeneous, magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Borovsky, J.E.

    1987-02-01

    The propagation of ultralow-frequency (ulf) electromagnetic signals (Alfven and magnetosonic waves) in collisional, inhomogeneous, magnetized plasmas is analyzed by numerical simulation. The problem is formulated from a Maxwell-equation orbit-theory approach rather than from a magnetohydrodynamic point of view, and the problem is numerically treated in a fully time-dependent manner. Boundary-value-problem behavior is distinguished from initial-value-problem behavior. The propagation of two-dimensional small-amplitude electromagnetic disturbances in plasmas with spatially dependent densities and in plasmas with spatially dependent conductivities is numerically simulated, and when possible, the simulations are compared with theory. Changes in the plasma density lead to changes in the signal speed and to reflections; collisions lead to changes in the signal speed, to reflections, and to attenuations. Theoretical descriptions based upon discontinuities in the media are generally incorrect in predicting the amplitudes of signals reflected from plasma inhomogeneities. 19 refs., 16 figs.

  4. Electron vortex magnetic holes: A nonlinear coherent plasma structure

    NARCIS (Netherlands)

    C.T. Haynes; D. Burgess; E. Camporeale (Enrico); T. Sundberg

    2015-01-01

    htmlabstractWe report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional particle-in-cell simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to electron mass ratio. These structures, electron

  5. Alfven Waves in a Cold Plasma with Curved Magnetic Fields

    Science.gov (United States)

    1988-06-01

    magnetic field. They discussed a possible method of avoiding spatially dependent eigenfrequencies which are not acceptable; they introduced an electric...1036, Hasegawa, A. 1974 12. Radoski, H. J. Geomag. Geoelectr ., v 25, P�, 1973 13. Kivelson, M., Geophys. Res. Letters, v 12, Southwood, D. pp 49-52

  6. Response of plasma rotation to resonant magnetic perturbations in J-TEXT tokamak

    Science.gov (United States)

    Yan, W.; Chen, Z. Y.; Huang, D. W.; Hu, Q. M.; Shi, Y. J.; Ding, Y. H.; Cheng, Z. F.; Yang, Z. J.; Pan, X. M.; Lee, S. G.; Tong, R. H.; Wei, Y. N.; Dong, Y. B.; J-TEXT Team

    2018-03-01

    The response of plasma toroidal rotation to the external resonant magnetic perturbations (RMP) has been investigated in Joint Texas Experimental Tokamak (J-TEXT) ohmic heating plasmas. For the J-TEXT’s plasmas without the application of RMP, the core toroidal rotation is in the counter-current direction while the edge rotation is near zero or slightly in the co-current direction. Both static RMP experiments and rotating RMP experiments have been applied to investigate the plasma toroidal rotation. The core toroidal rotation decreases to lower level with static RMP. At the same time, the edge rotation can spin to more than 20 km s‑1 in co-current direction. On the other hand, the core plasma rotation can be slowed down or be accelerated with the rotating RMP. When the rotating RMP frequency is higher than mode frequency, the plasma rotation can be accelerated to the rotating RMP frequency. The plasma confinement is improved with high frequency rotating RMP. The plasma rotation is decelerated to the rotating RMP frequency when the rotating RMP frequency is lower than the mode frequency. The plasma confinement also degrades with low frequency rotating RMP.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-08-31

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

  8. Quantum theory of the dielectric constant of a magnetized plasma and astrophysical applications. I.

    Science.gov (United States)

    Canuto, V.; Ventura, J.

    1972-01-01

    A quantum mechanical treatment of an electron plasma in a constant and homogeneous magnetic field is considered, with the aim of (1) defining the range of validity of the magnetoionic theory (2) studying the deviations from this theory, in applications involving high densities, and intense magnetic field. While treating the magnetic field exactly, a perturbation approach in the photon field is used to derive general expressions for the dielectric tensor. Numerical estimates on the range of applicability of the magnetoionic theory are given for the case of the 'one-dimensional' electron gas, where only the lowest Landau level is occupied.

  9. Magnetic field generation in Rayleigh-Taylor unstable inertial confinement fusion plasmas.

    Science.gov (United States)

    Srinivasan, Bhuvana; Dimonte, Guy; Tang, Xian-Zhu

    2012-04-20

    Rayleigh-Taylor instabilities (RTI) in inertial confinement fusion implosions are expected to generate magnetic fields. A Hall-MHD model is used to study the field generation by 2D single-mode and multimode RTI in a stratified two-fluid plasma. Self-generated magnetic fields are predicted and these fields grow as the RTI progresses via the ∇n(e)×∇T(e) term in the generalized Ohm's law. Scaling studies are performed to determine the growth of the self-generated magnetic field as a function of density, acceleration, Atwood number, and perturbation wavelength.

  10. A Probe Head for Simultaneous Measurements of Electrostatic and Magnetic Fluctuations in ASDEX Upgrade Edge Plasma

    DEFF Research Database (Denmark)

    Schrittwieser, R W; Ionita, C; Vianello, N

    2010-01-01

    For ASDEX Upgrade (AUG) a new probe head was developed for simultaneous measurements of electric and magnetic fluctuations in the edge plasma region. The probe head consists of a cylindrical graphite case. On the front side six graphite pins are mounted. With this arrangement the poloidal...... and radial electric field components, the ion saturation current and the current-voltage characteristic can be registered simultaneously. Inside the graphite case a magnetic sensor is mounted by which the three components of magnetic field fluctuations are measured. During the AUG discharges the probe head...

  11. Plasma expansion into a vacuum with an arbitrarily oriented external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    García-Rubio, F., E-mail: fernando.garcia.rubio@upm.es; Sanz, J. [E.T.S.I. Aeronáutica y del Espacio, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Ruocco, A. [Universitá degli studi di Napoli Federico II, 80138 Napoli (Italy)

    2016-01-15

    Plasma expansion into a vacuum with an external magnetic field is studied under the ideal magnetohydrodynamic hypothesis. The inclination of the magnetic field with respect to the expansion direction is arbitrary, and both the perpendicular and the oblique cases are separately analyzed. A self-similar solution satisfying the boundary conditions is obtained. The interface with the vacuum is treated as a fluid surface, and jump conditions concerning the momentum conservation are imposed. The effect of the intensity of the magnetic field and its inclination is thoroughly studied, and the consistency of the solution for small and large inclinations is investigated.

  12. Obliquely Propagating Electromagnetic Waves in Magnetized Kappa Plasmas

    Science.gov (United States)

    Gaelzer, R.

    2015-12-01

    The effects of velocity distribution functions (VDFs) that exhibit a power-law dependence on the high-energy tail have been the subjectof intense research by the space plasma community. Such functions, known as kappa or superthermal distributions, have beenfound to provide a better fitting to the VDF measured by spacecraft in the solar wind. One of the problems that is being addressed on this new light is the temperature anisotropy of solar wind protons and electrons. An anisotropic kappa VDF contains a large amount of free energy that can excite waves in the solar wind. Conversely, the wave-particle interaction is important to determine the shape of theobserved particle distributions.In the literature, the general treatment for waves excited by (bi-)Maxwellian plasmas is well-established. However, for kappa distributions, either isotropic or anisotropic, the wave characteristics have been studied mostly for the limiting cases of purely parallel or perpendicular propagation. Contributions for the general case of obliquely-propagating electromagnetic waves have been scarcely reported so far. The absence of a general treatment prevents a complete analysis of the wave-particle interaction in kappa plasmas, since some instabilities, such as the firehose, can operate simultaneously both in the parallel and oblique directions.In a recent work [1], we have obtained expressions for the dielectric tensor and dispersion relations for the low-frequency, quasi-perpendicular dispersive Alfvén waves resulting from a kappa VDF. In the present work, we generalize the formalism introduced by [1] for the general case of electrostatic and/or electromagnetic waves propagating in a kappa plasma in any frequency range and for arbitrary angles.We employ an isotropic distribution, but the methods used here can be easily applied to more general anisotropic distributions,such as the bi-kappa or product-bi-kappa. [1] R. Gaelzer and L. F. Ziebell, Journal of Geophysical Research 119, 9334

  13. Computing the complex : Dusty plasmas in the presence of magnetic fields and UV radiation

    Science.gov (United States)

    Land, V.

    2007-12-01

    the void towards the outside of the discharge. The void thus requires electron-impact ionizations inside the void. The electrons gain the energy for these ionizations inside the dust cloud surrounding the void, however. We show that a growing electron temperature gradient is responsible for the transport of electron energy from the surrounding dust cloud into the void. An axial magnetic field in the discharge magnetizes the electrons. This changes the ambipolar flux of ions through the bulk of the discharge. The ion drag force changes, resulting in a differently shaped void and faster void formation. Experiments in a direct current discharge, show a response of both dust and plasma in the E?B direction, when a magnetic field is applied. The dust response consists of two phases: an initial fast phase, and a later, slow phase. Using a Particle-In-Cell plus Monte Carlo model, we show that the dust charge can be reduced by adding a flux of ultraviolet radiation. A source of ultraviolet light can thus serve as a tool to manipulate dusty plasmas, but might also be important for the coagulation of dust particles around young stars and planet formation in general.

  14. Determination of self generated magnetic field and the plasma density using Cotton Mouton polarimetry with two color probes

    Directory of Open Access Journals (Sweden)

    Joshi A.S.

    2013-11-01

    Full Text Available Self generated magnetic fields (SGMF in laser produced plasmas are conventionally determined by measuring the Faraday rotation angle of a linearly polarized laser probe beam passing through the plasma along with the interferogram for obtaining plasma density. In this paper, we propose a new method to obtain the plasma density and the SGMF distribution from two simultaneous measurements of Cotton Mouton polarimetry of two linearly polarized probe beams of different colors that pass through plasma in a direction normal to the planar target. It is shown that this technique allows us to determine the distribution of SGMF and the plasma density without doing interferometry of laser produced plasmas.

  15. Enhancement in recovery of drugs with high protein binding efficiency from human plasma using magnetic nanoparticles.

    Science.gov (United States)

    Bhati, Aniruddha; Desai, Rucha P; Ramchand, C N

    2017-09-05

    In this paper, we propose an alternate method for bioanalytical extraction of drugs from human plasma samples using bare magnetic nanoparticles. The magnetic nanoparticles (MNPs) were used for deproteination of biological samples that further assist in extraction of plasma bound drugs for bioanalytical studies. The method uses basic solvents (ethanol, methanol, etc.) rather than the expensive and toxic solvents. The MNPs provide several advantages like avoiding the use of centrifuge machine, and making extraction time effective. The average time involved for the sample preparation is around 30-40min. The developed method was examined for seven different drugs having moderate (40-70%) to high (>80%) plasma protein binding efficiency. The present study focuses on the principle of magnetic nanoparticle based extraction of drug that binds with the plasma protein. In calcitriol (protein binding efficiency >99%), it was observed that the drug extraction efficiency could be enhanced by 16% using the present method. However, we assume that still there is a scope for improving the extraction efficiency by optimizing proper solvent for the specific drug. The use of magnetic nanoparticles makes the extraction cost effective and quick with improved efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Magnetic and electric deflector spectrometers for ion emission analysis from laser generated plasma

    Science.gov (United States)

    Torrisi, Lorenzo; Costa, Giuseppe; Ceccio, Giovanni; Cannavò, Antonino; Restuccia, Nancy; Cutroneo, Mariapompea

    2018-01-01

    The pulsed laser-generated plasma in vacuum and at low and high intensities can be characterized using different physical diagnostics. The charge particles emission can be characterized using magnetic, electric and magnet-electrical spectrometers. Such on-line techniques are often based on time-of-flight (TOF) measurements. A 90° electric deflection system is employed as ion energy analyzer (IEA) acting as a filter of the mass-to-charge ratio of emitted ions towards a secondary electron multiplier. It determines the ion energy and charge state distributions. The measure of the ion and electron currents as a function of the mass-to-charge ratio can be also determined by a magnetic deflector spectrometer, using a magnetic field of the order of 0.35 T, orthogonal to the ion incident direction, and an array of little ion collectors (IC) at different angles. A Thomson parabola spectrometer, employing gaf-chromix as detector, permits to be employed for ion mass, energy and charge state recognition. Mass quadrupole spectrometry, based on radiofrequency electric field oscillations, can be employed to characterize the plasma ion emission. Measurements performed on plasma produced by different lasers, irradiation conditions and targets are presented and discussed. Complementary measurements, based on mass and optical spectroscopy, semiconductor detectors, fast CCD camera and Langmuir probes are also employed for the full plasma characterization. Simulation programs, such as SRIM, SREM, and COMSOL are employed for the charge particle recognition.

  17. Magnetic and electric deflector spectrometers for ion emission analysis from laser generated plasma

    Directory of Open Access Journals (Sweden)

    Torrisi Lorenzo

    2018-01-01

    Full Text Available The pulsed laser-generated plasma in vacuum and at low and high intensities can be characterized using different physical diagnostics. The charge particles emission can be characterized using magnetic, electric and magnet-electrical spectrometers. Such on-line techniques are often based on time-of-flight (TOF measurements. A 90° electric deflection system is employed as ion energy analyzer (IEA acting as a filter of the mass-to-charge ratio of emitted ions towards a secondary electron multiplier. It determines the ion energy and charge state distributions. The measure of the ion and electron currents as a function of the mass-to-charge ratio can be also determined by a magnetic deflector spectrometer, using a magnetic field of the order of 0.35 T, orthogonal to the ion incident direction, and an array of little ion collectors (IC at different angles. A Thomson parabola spectrometer, employing gaf-chromix as detector, permits to be employed for ion mass, energy and charge state recognition. Mass quadrupole spectrometry, based on radiofrequency electric field oscillations, can be employed to characterize the plasma ion emission. Measurements performed on plasma produced by different lasers, irradiation conditions and targets are presented and discussed. Complementary measurements, based on mass and optical spectroscopy, semiconductor detectors, fast CCD camera and Langmuir probes are also employed for the full plasma characterization. Simulation programs, such as SRIM, SREM, and COMSOL are employed for the charge particle recognition.

  18. Preparation of magnetized nanodusty plasmas in a radio frequency-driven parallel-plate reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tadsen, Benjamin, E-mail: tadsen@physik.uni-kiel.de; Greiner, Franko; Piel, Alexander [IEAP, Christian-Albrechts-Universität, D-24098 Kiel (Germany)

    2014-10-15

    Nanodust is produced in an rf-driven push-pull parallel-plate reactor using argon with an acetylene admixture at 5–30 Pa. A scheme for the preparation of nanodust clouds with particle radii up to 400 nm for investigations in magnetized plasmas is proposed. The confinement that keeps the nanodust of different radii inside a moderately magnetized discharge (B ≤ 500 mT) is investigated by a comparison of 2d-Langmuir probe measurements in the dust-free plasma without and with a magnetic field and by the analysis of scattered light of nanodust clouds. It is shown that the dust cloud changes its shape when the dust density changes. This results in a reversed α-γ{sup ′} transition from a dense dust cloud with a central disk-like void to a dilute dust cloud with a toroidal void. When the dust density is further reduced, filaments are observed in the central part of the cloud, which were absent in the high-density phase. It is concluded that the dense nanodust cloud is able to suppress plasma filamentation in magnetized plasmas.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  20. Equilibrium fluctuations formulas for the quantum one-component plasma in a magnetic field

    NARCIS (Netherlands)

    John, P.; Suttorp, L.G.

    1993-01-01

    The authors derive a complete set of equilibrium fluctuation formulae for the charge density, the current density and the energy density of the quantum one-component plasma in a magnetic field. The derivation is based on the use of imaginary-time-dependent Green functions and their Kubo transforms.

  1. Fluctuations properties and collective modes of quantum plasmas in a magnetic field

    NARCIS (Netherlands)

    Suttorp, L.G.; Van Horn, H.M.; Ichimaru, S.

    1993-01-01

    A complete set of equilibrium fluctuation formulas for the charge density, the momentum density and the energy density of a magnetized one-component quantum plasma is presented. The derivation is based on the use of equations of motion for Fourier-transformed imaginary-time Green functions. The

  2. Dynamics of magnetic fields in high-energy-density plasmas for fusion and astrophysics

    Science.gov (United States)

    Gao, Lan; Ji, H.; Fox, W.; Hill, K.; Efthimion, P.; Nilson, P.; Igumenshchev, I.; Froula, D.; Betti, R.; Meyerhofer, D.; Fiksel, G.; Blackman, E.; Schneider, M.; Chen, H.; Smalyuk, V.; Li, H.; Casner, A.

    2015-11-01

    An overview of our recent experimental and theoretical work on the dynamics of magnetic fields in high-energy-density plasmas will be presented. This includes: (1) precision mapping of the self-generated magnetic fields in the coronal plasma and the Nernst effect on their evolution, (2) characterizing the strong magnetic field generated by a laser-driven capacitor-coil target using ultrafast proton radiography, and (3) creating MHD turbulence in Rayleigh-Taylor unstable plasmas. The experimental results are compared with resistive MHD simulations providing a stringent test for their predictions. Applications in relevance to ignition target designs in inertial confinement fusion, material strength studies in high-energy-density physics, and astrophysical systems such as plasma dynamos and magnetic reconnection will be discussed. Future experiments proposed on the National Ignition Facility will be described. This material is supported in part by the Department of Energy National Nuclear Security Administration under Award No. DE-NA0001944, and the National Laser Users Facility under Grant No. DE-NA0002205.

  3. Magnetic Effects in a Moderate-Temperature, High-Beta, Toroidal Plasma Device

    Science.gov (United States)

    Edwards, W. F.; Singh, A. K.; Held, E. D.

    2011-10-01

    A small toroidal machine (STOR-1M; minor radius 4.5 cm), on loan from the University of Saskatchewan, has been modified to operate at hydrogen ionization levels ~0.1%, beta values between 0.1 and 1, electron number density ~5x1016/m3, temperature ~5 eV, and applied toroidal magnetic field ~20 gauss. Plasma is generated using magnetron-produced microwaves. Langmuir and Hall probes determine radial profiles of electron number density, temperature, and magnetic field. For most values of the externally-applied magnetic field, the internal field is the same with or without plasma, however, in a narrow window of B, diamagnetism and other effects are present. The effect is observed with no externally induced current; plasma currents are self generated through some sort of relaxation process. Beta and radius conditions correlate well with similar magnetic structures in the laboratory (eg., plasma focus, Z pinch) and in space (eg., Venus flux ropes, solar coronal loops).

  4. Transient dynamics of secondary radiation from an HF pumped magnetized space plasma

    NARCIS (Netherlands)

    Norin, L.; Grach, S. M.; Thide, B.; Sergeev, E. N.; Leyser, T. B.

    2007-01-01

    In order to systematically analyze the transient wave and radiation processes that are excited when a high-frequency (HF) radio wave is injected into a magnetized space plasma, we have measured the secondary radiation, or stimulated electromagnetic emission ( SEE), from the ionosphere,

  5. Magnetic field generation in rotating plasma waves driven by co-propagating OAM lasers

    Science.gov (United States)

    Shi, Yin; Vieira, Jorge; Trines, Raoul; Bingham, Bob; Shen, Baifei; Kingham, Robert

    2017-10-01

    We present a new magnetic field generation mechanism in underdense plasma due to rotating plasma waves driven by co-propagating Laguerre-Gaussian (LG) beating orbital angular momentum (OAM) laser beams with both a different frequency and also different twist index. In this plasma wave, particles oscillate elliptically in the transverse plane with an azimuthally dependent phase. We therefore call it a transverse rotating plasma wave (TRPW). The distribution and evolution of density and electric field in the transverse plane has some special characteristics. We present a linear fluid model of TRPW and also a high order analysis of the electrical current based on particle motion. To the second order, there is a net rotating current leading to the onset of an intense axial magnetic field (up to 0.4 MG), which persists over a long time in the plasma (ps scale). It is different from Inverse Faraday effects. Our analytical predictions are confirmed in three-dimensional particle-in-cell simulations using EPOCH. This new method of magnetic field creation may find applications in charged beam collimation and controlled fusion. Dr Yin Shi is a Newton International Fellow. This work is supported by the Royal Society. This work used the ARCHER UK National Supercomputing Service.

  6. Plans and Progress of Electrode Biased Plasmas in the Magnetic Reconnection Experiment

    Science.gov (United States)

    Martin, E. H.; Gerhardt, S. P.; Yamada, M.; Ji, H.; Ren, Y.; Dorfman, S.; Torreblanca, H.

    2006-10-01

    Compact Toroid (CT) plasmas such as Spheromaks are known to exhibit a global instability known as the tilt mode, where the magnetic moment of the CT tilts to align itself with the external magnetic field, as well as other non-rigid body instabilities. Possible tilt stabilizing mechanisms for these instabilities include external field shaping, nearby passive stabilizers, and plasma rotation. The proposed research focuses on reducing the growth of the tilt instability by introducing toroidal rotation in spheromaks formed in MRX. Rotation is introduced by the use of interior and exterior electrodes; the result is a Jbias x Binternal torque on the CT plasma which in turn leads to toroidal rotation of the CT plasma. In order to power the bias electrode a 450 V 8800 μF capacitor bank capable of delivering up to 450 amperes was constructed along with the required control and triggering circuitry. Solid state switches allow for fast turn on and turn off times of Jbias. The bias current and the voltage drop across the electrodes are measured using a current shunt and voltage divider respectively, and the resulting flow is measured with a Mach probe. Internal arrays of magnetic probes and optical diagnostics will be used to parameterize the performance of the CT plasma during bias. Construction and testing of all necessary components and diagnostics is complete; preliminary results will be presented.

  7. Topology of magnetic flux ropes and formation of fossil flux transfer events and boundary layer plasmas

    Science.gov (United States)

    Lee, L. C.; Ma, Z. W.; Fu, Z. F.; Otto, A.

    1993-01-01

    A mechanism for the formation of fossil flux transfer events and the low-level boundary layer within the framework of multiple X-line reconnection is proposed. Attention is given to conditions for which the bulk of magnetic flux in a flux rope of finite extent has a simple magnetic topology, where the four possible connections of magnetic field lines are: IMF to MSP, MSP to IMF, IMF to IMF, and MSP to MSP. For a sufficient relative shift of the X lines, magnetic flux may enter a flux rope from the magnetosphere and exit into the magnetosphere. This process leads to the formation of magnetic flux ropes which contain a considerable amount of magnetosheath plasma on closed magnetospheric field lines. This process is discussed as a possible explanation for the formation of fossil flux transfer events in the magnetosphere and the formation of the low-latitude boundary layer.

  8. Dynamics of sheath-connected plasma filaments in magnetic field with arbitrary geometry

    Directory of Open Access Journals (Sweden)

    A.A. Stepanenko

    2017-08-01

    Full Text Available We present the results of analysis of sheath-connected blob dynamics in magnetic field with arbitrary geometry. For the case of magnetic configurations with small curvature of the field lines it is demonstrated that motion of a plasma filament can be described by a single time-independent effective potential. Dynamics of blobs in magnetic fields with non-zero curvature of the field lines is also analyzed and we show that depending on filament dimensions and geometry of the magnetic field blobs can demonstrate different propagation patterns. The qualitative results of the presented analysis are supplied with results of simulations of filament dynamics in sheared and non-sheared tokamak-like magnetic configurations.

  9. Transient magnetized plasma as an optical element for high power laser pulses

    Directory of Open Access Journals (Sweden)

    Nobuhiko Nakanii

    2015-02-01

    Full Text Available Underdense plasma produced in gas jets by low intensity laser prepulses in the presence of a static magnetic field, B∼0.3  T, is shown experimentally to become an optical element allowing steering of tightly focused high power femtosecond laser pulses within several degrees along with essential enhancement of pulse’s focusability. Strong laser prepulses form a density ramp perpendicularly to magnetic field direction and, owing to the light refraction, main laser pulses propagate along the magnetic field even if it is tilted from the laser axis. Electrons generated in the laser pulse wake are well collimated and follow in the direction of the magnetic field; their characteristics are measured to be not sensitive to the tilt of magnetic field up to angles ±5°.

  10. Magnetic Ignition of Pulsed Gas Discharges in Air of Low Pressure in a Coaxial Plasma Gun

    Science.gov (United States)

    Thom, Karlheinz; Norwood, Joseph, Jr.

    1961-01-01

    The effect of an axial magnetic field on the breakdown voltage of a coaxial system of electrodes has been investigated by earlier workers. For low values of gas pressure times electrode spacing, the breakdown voltage is decreased by the application of the magnetic field. The electron cyclotron radius now assumes the role held by the mean free path in nonmagnetic discharges and the breakdown voltage becomes a function of the magnetic flux density. In this paper the dependence of the formative time lag as a function of the magnetic flux density is established and the feasibility of using a magnetic field for igniting high-voltage, high-current discharges is shown through theory and experiment. With a 36 microfarad capacitor bank charged to 48,000 volts, a peak current of 1.3 x 10( exp 6) amperes in a coaxial type of plasma gun was achieved with a current rise time of only 2 microseconds.

  11. Stochastic acceleration by a single wave in a magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.

    1977-09-22

    A particularly simple problem exhibiting stochasticity is the motion of a charged particle in a uniform magnetic field and a single wave. Detailed studies of this wave-particle interaction show the following features. An electrostatic wave propagating obliquely to the magnetic field causes stochastic motion if the wave amplitude exceeds a certain threshold. The overlap of cyclotron resonances then destroys a constant of the motion, allowing strong particle acceleration. A wave of large enough amplitude would thus suffer severe damping and lead to rapid heating of a particle distribution. The stochastic motion resembles a diffusion process even though the wave spectrum contains only a single wave. The motion of ions in a nonuniform magnetic field and a single electrostatic wave is treated in our study of a possible saturation mechanism of the dissipative trapped-ion instability in a tokamak. A theory involving the overlap of bounce resonances predicts the main features found in the numerical integration of the equations of motion. Ions in a layer near the trapped-circulating boundary move stochastically. This motion leads to nonlinear stabilization mechanisms which are described qualitatively.

  12. Cooling force on ions in a magnetized electron plasma

    Directory of Open Access Journals (Sweden)

    Hrachya B. Nersisyan

    2013-07-01

    Full Text Available Electron cooling is a well-established method to improve the phase space quality of ion beams in storage rings. In the common rest frame of the ion and the electron beam, the ion is subjected to a drag force and it experiences a loss or a gain of energy which eventually reduces the energy spread of the ion beam. A calculation of this process is complicated as the electron velocity distribution is anisotropic and the cooling process takes place in a magnetic field which guides the electrons. In this paper the cooling force is calculated in a model of binary collisions (BC between ions and magnetized electrons, in which the Coulomb interaction is treated up to second order as a perturbation to the helical motion of the electrons. The calculations are done with the help of an improved BC theory which is uniformly valid for any strength of the magnetic field and where the second-order two-body forces are treated in the interaction in Fourier space without specifying the interaction potential. The cooling force is explicitly calculated for a regularized and screened potential which is both of finite range and less singular than the Coulomb interaction at the origin. Closed expressions are derived for monochromatic electron beams, which are folded with the velocity distributions of the electrons and ions. The resulting cooling force is evaluated for anisotropic Maxwell velocity distributions of the electrons and ions.

  13. Effects of magnetized plasma on the propagation properties of obliquely incident THz waves

    Directory of Open Access Journals (Sweden)

    Yunxian Tian

    2017-12-01

    Full Text Available In this paper, the propagation of obliquely incident terahertz (THz wave in a non-uniform magnetized plasma slab is investigated. The electron density and the collision frequency across the plasma are assumed to have a Gaussian profile. To deal with the non-uniform profile, the plasma slab is divided into a series of subslabs. For more accuracy, twice reflection between the interfaces of each subslab is considered, and the corresponding transmitted and reflected power are derived. Effects of collision frequency, magnetic field amplitude and incident angle on THz wave propagation characteristics are investigated. Specifically, the refraction angles in each subslab are presented. These simulation results are meaningful for the hypersonic flight communication.

  14. Effect of magnetic perturbations on the 3D MHD self-organization of shaped tokamak plasmas

    CERN Document Server

    Bonfiglio, D; Veranda, M; Chacón, L; Escande, D F

    2016-01-01

    The effect of magnetic perturbations (MPs) on the helical self-organization of shaped tokamak plasmas is discussed in the framework of the nonlinear 3D MHD model. Numerical simulations performed in toroidal geometry with the \\textsc{pixie3d} code [L. Chac\\'on, Phys. Plasmas {\\bf 15}, 056103 (2008)] show that $n=1$ MPs significantly affect the spontaneous quasi-periodic sawtoothing activity of such plasmas. In particular, the mitigation of sawtooth oscillations is induced by $m/n=1/1$ and $2/1$ MPs. These numerical findings provide a confirmation of previous circular tokamak simulations, and are in agreement with tokamak experiments in the RFX-mod and DIII-D devices. Sawtooth mitigation via MPs has also been observed in reversed-field pinch simulations and experiments. The effect of MPs on the stochastization of the edge magnetic field is also discussed.

  15. Nonlinear low frequency electrostatic structures in a magnetized two-component auroral plasma

    Energy Technology Data Exchange (ETDEWEB)

    Rufai, O. R., E-mail: rajirufai@gmail.com [University of the Western Cape, Bellville 7535, Cape-Town (South Africa); Scientific Computing, Memorial University of Newfoundland, St John' s, Newfoundland and Labrador A1C 5S7 (Canada); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Bellville 7535, Cape-Town (South Africa); Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [University of the Western Cape, Bellville 7535, Cape-Town (South Africa); Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai 410218 (India)

    2016-03-15

    Finite amplitude nonlinear ion-acoustic solitons, double layers, and supersolitons in a magnetized two-component plasma composed of adiabatic warm ions fluid and energetic nonthermal electrons are studied by employing the Sagdeev pseudopotential technique and assuming the charge neutrality condition at equilibrium. The model generates supersoliton structures at supersonic Mach numbers regime in addition to solitons and double layers, whereas in the unmagnetized two-component plasma case only, soliton and double layer solutions can be obtained. Further investigation revealed that wave obliqueness plays a critical role for the evolution of supersoliton structures in magnetized two-component plasmas. In addition, the effect of ion temperature and nonthermal energetic electron tends to decrease the speed of oscillation of the nonlinear electrostatic structures. The present theoretical results are compared with Viking satellite observations.

  16. Low-frequency shock waves in a magnetized superthermal dusty plasma

    Science.gov (United States)

    Chahal, B. S.; Ghai, Yashika; Saini, N. S.

    2017-09-01

    The characteristics of low-frequency shocks in a magnetized dusty plasma comprising of negatively charged dust fluid, kappa-distributed electrons and ions have been investigated. Using the reductive perturbation method, the nonlinear Korteweg de-Vries-Burgers (KdV-B) equation which governs the dynamics of the dust acoustic (DA) shock waves is derived. The characteristics of shock structures are studied under the influence of various plasma parameters, viz. superthermality of ions, magnetic field, electron-to-dust-density ratio, kinematic viscosity, ion-to-electron-temperature ratio and obliqueness. The combined effects of these physical parameters significantly influence the characteristics of DA shock structures. It is observed that only negative potential shocks exist in a plasma environment comprising of dust fluid and superthermal electrons and ions such as that of Saturn's magnetosphere.

  17. Observation of magnetic field generation via the Weibel instability in interpenetrating plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Huntington, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fiuza, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ross, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zylstra, A. B. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Drake, R. P. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Atmospheric, Oceanic, and Space Sciences; Froula, D. H. [Univ. of Rochester, NY (United States). Physics Dept. and Lab. for Laser Energetics; Gregori, G. [Univ. of Oxford (United Kingdom). Dept. of Physics; Kugland, N. L. [Lam Research Corp., Fremont, CA (United States); Kuranz, C. C. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Atmospheric, Oceanic, and Space Sciences; Levy, M. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Li, C. K. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Meinecke, J. [Univ. of Oxford (United Kingdom). Dept. of Physics; Morita, T. [Osaka Univ. (Japan). Inst. of Laser Engineering; Petrasso, R. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Plechaty, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Remington, B. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sakawa, Y. [Osaka Univ. (Japan). Inst. of Laser Engineering; Spitkovsky, A. [Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences; Takabe, H. [Osaka Univ. (Japan). Inst. of Laser Engineering; Park, H.-S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-01-19

    Collisionless shocks can be produced as a result of strong magnetic fields in a plasma flow, and therefore are common in many astrophysical systems. The Weibel instability is one candidate mechanism for the generation of su fficiently strong fields to create a collisionless shock. Despite their crucial role in astrophysical systems, observation of the magnetic fields produced by Weibel instabilities in experiments has been challenging. Using a proton probe to directly image electromagnetic fields, we present evidence of Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows from laser-driven laboratory experiments. Three-dimensional particle-in-cell simulations reveal that the instability effi ciently extracts energy from the plasma flows, and that the self-generated magnetic energy reaches a few percent of the total energy in the system. Furthermore, this result demonstrates an experimental platform suitable for the investigation of a wide range of astrophysical phenomena, including collisionless shock formation in supernova remnants, large-scale magnetic field amplification, and the radiation signature from gamma-ray bursts.

  18. Observation of Rayleigh-Taylor-instability growth in a plasma regime with magnetic and viscous stabilization

    Science.gov (United States)

    Adams, Colin

    2015-11-01

    Rayleigh-Taylor-instability (RTI) growth during the interaction between a high-Mach-number, unmagnetized plasma jet and a stagnated, magnetized plasma is observed in a regime where the growth of short-wavelength modes is influenced by plasma viscosity and magnetic fields. The time evolution of mode growth at the mostly planar interface is captured by a multi-frame fast camera. Interferometry, spectroscopy, photodiode, and magnetic probe diagnostics are employed to experimentally infer ni, Te, Z , acceleration, B -->, and ion viscosity in the vicinity of the evolving interface. As the instability grows, an evolution from mode wavelengths of ~ 1 . 7 cm to ~ 2 . 8 cm is observed. The growth time (~ 10 μs) and wavelength (~ 1 cm) of the observed modes agree with theoretical predictions computed from the experimentally inferred density (~1014 cm-3), deceleration (~109 m /s2), and magnetic field (~ 15 G in direction of wavevector). Furthermore, comparisons of experimental data with idealized magnetohydrodynamic simulations (which include a physical viscosity model) suggest that both magnetic and viscous stabilization contribute to the observed mode evolution. These data are relevant for benchmarking astrophysical and magneto-inertial-fusion-relevant computations of RTI. Supported by the LANL LDRD Program; PLX facility construction supported by OFES.

  19. Electron cooling and finite potential drop in a magnetized plasma expansion

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Sanchez, M. [Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Navarro-Cavallé, J. [Escuela Técnica Superior de Ingeniería Aeronáutica y del Espacio, Universidad Politécnica de Madrid, Plaza Cardenal Cisneros 3, Madrid 28040 (Spain); Ahedo, E. [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Avda. Universidad 30, Leganés 28911, Madrid (Spain)

    2015-05-15

    The steady, collisionless, slender flow of a magnetized plasma into a surrounding vacuum is considered. The ion component is modeled as mono-energetic, while electrons are assumed Maxwellian upstream. The magnetic field has a convergent-divergent geometry, and attention is restricted to its paraxial region, so that 2D and drift effects are ignored. By using the conservation of energy and magnetic moment of particles and the quasi-neutrality condition, the ambipolar electric field and the distribution functions of both species are calculated self-consistently, paying attention to the existence of effective potential barriers associated to magnetic mirroring. The solution is used to find the total potential drop for a set of upstream conditions, plus the axial evolution of various moments of interest (density, temperatures, and heat fluxes). The results illuminate the behavior of magnetic nozzles, plasma jets, and other configurations of interest, showing, in particular, in the divergent plasma the collisionless cooling of electrons, and the generation of collisionless electron heat fluxes.

  20. Development of Plasma Fluid Model for a Microwave Rocket Supported by a Magnetic Field

    Science.gov (United States)

    Takahashi, Masayuki

    2017-10-01

    A uid model of plasma transport is developed to reproduce a plasma pattern induced by microwave irradiation when an external magnetic field is applied to the breakdown volume. Transport coefficients in the uid model are evaluated using a fully kinetic simulation under a magnetic field to maintain consistency of electron transport between the particle and uid models. The electron-density profile and propagation speed of the ionization front obtained by the uid model agree with those of the particle model. Multidimensional or longer time-scale simulations can be conducted using the uid model in the case of the application of an external magnetic field, with the simulation reducing computational cost compared to the fully kinetic model.

  1. SXR-XUV Diagnostics for Edge and Core of Magnetically Confined Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Stutman, Dan [Johns Hopkins University

    2014-09-10

    The present report summarizes the results obtained during a one-year extension of DoE grant “SXR-XUV Diagnostics for Edge and Core of Magnetically Confined Plasmas”, at Johns Hopkins University, aimed at completing the development of a new type of magnetic fusion plasma diagnostic, the XUV Transmission Grating Imaging Radiometer (TGIR). The TGIR enables simultaneous spatially and spectrally resolved measurements of the XUV/VUV radiated power from impurities in fusion plasmas, with high speed. The instrument was successfully developed and qualified in the laboratory and in experiments on a tokamak. Its future applications will be diagnostic of the impurity content and transport in the divertor and edge of advanced magnetic fusion experiments, such as NSTX Upgrade.

  2. Astrophysics of magnetically collimated jets generated from laser-produced plasmas.

    Science.gov (United States)

    Ciardi, A; Vinci, T; Fuchs, J; Albertazzi, B; Riconda, C; Pépin, H; Portugall, O

    2013-01-11

    The generation of astrophysically relevant jets, from magnetically collimated, laser-produced plasmas, is investigated through three-dimensional, magnetohydrodynamic simulations. We show that for laser intensities I∼10(12)-10(14) W cm(-2), a magnetic field in excess of ∼0.1  MG, can collimate the plasma plume into a prolate cavity bounded by a shock envelope with a standing conical shock at its tip, which recollimates the flow into a supermagnetosonic jet beam. This mechanism is equivalent to astrophysical models of hydrodynamic inertial collimation, where an isotropic wind is focused into a jet by a confining circumstellar toruslike envelope. The results suggest an alternative mechanism for a large-scale magnetic field to produce jets from wide-angle winds.

  3. Modification of plasma rotation with resonant magnetic perturbations in the STOR-M tokamak

    Science.gov (United States)

    Elgriw, S.; Liu, Y.; Hirose, A.; Xiao, C.

    2016-04-01

    The toroidal plasma flow velocity of impurity ions has been significantly modified in the Saskatchewan Torus-Modified (STOR-M) tokamak by means of resonant magnetic perturbations (RMP). It has been found that the toroidal flow velocities of OV and CVI impurity ions change towards the co-current direction after the application of a current through a set of (l  =  2, n  =  1) RMP field coils. It has been observed that the reduction of the toroidal flow velocity is closely correlated to the reduction of the magnetohydrodynamic (MHD) fluctuation frequency measured by Mirnov coils. Modulation of the flow velocity has been achieved by switching the RMP current pulses. Non-resonant magnetic perturbations have also induced a much smaller change in the toroidal plasma flow. A theoretical model has been adopted to assess the contributions of different drift mechanisms to magnetic islands rotation in STOR-M.

  4. Experimental validation of a filament transport model in turbulent magnetized plasmas

    CERN Document Server

    Carralero, D; Aho-Mantila, L; Birkenmeier, G; Brix, M; Groth, M; Müller, H W; Stroth, U; Vianello, N; Wolfrum, E; Contributors, JET

    2015-01-01

    In a wide variety of natural and laboratory magnetized plasmas, filaments appear as a result of interchange instability. These convective structures substantially enhance transport in the direction perpendicular to the magnetic field. According to filament models, their propagation may follow different regimes depending on the parallel closure of charge conservation. This is of paramount importance in magnetic fusion plasmas, as high collisionality in the scrape-off layer may trigger a regime transition leading to strongly enhanced perpendicular particle fluxes. This work reports for the first time on an experimental verification of this process, linking enhanced transport with a regime transition as predicted by models. Based on these results, a novel scaling for global perpendicular particle transport in reactor relevant tokamaks such as ASDEX-Upgrade and JET is found, leading to important implications for next generation fusion devices.

  5. Parametric excitation of optical phonons in weakly polar narrow band gap magnetized semiconductor plasmas

    Science.gov (United States)

    Sandeep; Dahiya, Sunita; Singh, Navneet

    2017-11-01

    An analytical treatment based on the hydrodynamic model of plasmas is developed to study parametric amplification and oscillation of optical phonon modes in weakly polar narrow direct-gap magnetized semiconductor plasmas. Second-order optical susceptibility arising due to nonlinear polarization and the basic operational characteristics of the parametric device, viz. threshold nature, power gain mechanisms and conversion efficiency, are obtained. The effects of doping, magnetic field and excitation intensity, on the above operational characteristics have been studied in detail. Numerical estimates are made for an n-InSb crystal at 5 K duly irradiated by a pulsed 10.6 μm CO2 laser. The analysis suggests the possibility of observing super-fluorescent parametric emission and oscillation in moderately doped n-InSb crystal under off-resonant nanosecond pulsed not-too-high power laser irradiation, the crystal being immersed in a large magnetic field.

  6. Laser-Plasma Interaction in Presence of an Obliquely External Magnetic Field: Application to Laser Fusion without Radioactivity

    Science.gov (United States)

    Mobaraki, M.; Jafari, S.

    2016-08-01

    In this paper, the nonlinear interaction of ultra-high power laser beam with fusion plasma at relativistic regime in the presence of obliquely external magnetic Geld has been studied. Imposing an external magnetic Geld on plasma can modify the density profile of the plasma so that the thermal conductivity of electrons reduces which is considered to be the decrease of the threshold energy for ignition. To achieve the fusion of Hydrogen-Boron (HB) fuel, the block acceleration model of plasma is employed. Energy production by HB isotopes can be of interest, since its reaction does not generate radioactive tritium. By using the inhibit factor in the block model acceleration of plasma and Maxwell's as well as the momentum transfer equations, the electron density distribution and dielectric permittivity of the plasma medium are obtained. Numerical results indicate that with increasing the intensity of the external magnetic field, the oscillation of the laser magnetic field decreases, while the dielectric permittivity increases. Moreover, the amplitude of the electron density becomes highly peaked and the plasma electrons are strongly bunched with increasing the intensity of external magnetic field. Therefore, the magnetized plasma can act as a positive focusing lens to enhance the fusion process. Besides, we find that with increasing θ-angle (from oblique external magnetic field) between 0 and 90°, the dielectric permittivity increases, while for θ between 90° and 180°, the dielectric permittivity decreases with increasing θ.

  7. Study of electromagnetic compatibility requirements of spacecrafts in magnetized plasma with FDTD method

    Science.gov (United States)

    Miyake, T.; Amagasu, Y.; Maeda, H.; Okada, T.; Ishisaka, K.

    2006-12-01

    Spacecrafts have many sensors and instruments onboard themselves to observe various scientific data in space plasma. It is very important for electromagnetic compatibility (EMC) requirements of spacecrafts to identify the propagation characteristics of electromagnetic noises emitted from instruments onboard themselves. To solve this problem of EMC requirements of spacecraft, we developed a FDTD simulation code which can treat wave propagations in magnetized plasma, and performed FDTD simulations of electromagnetic noises which propagate in space plasma. Though we need to perform full particle simulations in order to recognize complete characteristic of waves propagating in space plasma, FDTD simulations can be performed with much less computer resources than those necessary for full particle simulations, in memories as well as cpu time. In providing EMC requirements of spacecrafts, we have to perform many simulations with various conditions, therefore, FDTD simulation is a very effective method. In this study, we study about sheilding effects of the conductive hood onboard spacecraft in preventing electromagnetic noises emitted from the spacecraft itself. Especially, we focus on the influences of the angle of the conductive hood and the direction of the ambient magnetic fields. We performed a series of three-dimensional FDTD simulations of electromagnetic noises around spacecraft in magnetized plasma, and confirmed shielding effects of the conductive hood onboard spacecraft. We input gaussian pulses as a wave source of electromagnetic noises. At first, we assume the ambient mangetic field parallel to the z-axis. Since FDTD simulations can be performed with less computer resources, we can perform many simulation experiments with various conditions. In this study, we perform a series of simulations with varying the shape of conductive hood and the direction of the ambient magnetic field. This method with FDTD simulations is very effective tool for providing EMC

  8. Oblique Interaction of Dust-ion Acoustic Solitons with Superthermal Electrons in a Magnetized Plasma

    Science.gov (United States)

    Parveen, Shahida; Mahmood, Shahzad; Adnan, Muhammad; Qamar, Anisa

    2018-01-01

    The oblique interaction between two dust-ion acoustic (DIA) solitons travelling in the opposite direction, in a collisionless magnetized plasma composed of dynamic ions, static dust (positive/negative) charged particles and interialess kappa distributed electrons is investigated. By employing extended Poincaré-Lighthill-Kuo (PLK) method, Korteweg-de Vries (KdV) equations are derived for the right and left moving low amplitude DIA solitons. Their trajectories and corresponding phase shifts before and after their interaction are also obtained. It is found that in negatively charged dusty plasma above the critical dust charged to ion density ratio the positive polarity pulse is formed, while below the critical dust charged density ratio the negative polarity pulse of DIA soliton exist. However it is found that only positive polarity pulse of DIA solitons exist for the positively charged dust particles case in a magnetized nonthermal plasma. The nonlinearity coefficient in the KdV equation vanishes for the negatively charged dusty plasma case for a particular set of parameters. Therefore, at critical plasma density composition for negatively charged dust particles case, the modified Korteweg-de Vries (mKdV) equations having cubic nonlinearity coefficient of the DIA solitons, and their corresponding phase shifts are derived for the left and right moving solitons. The effects of the system parameters including the obliqueness of solitons propagation with respect to magnetic field direction, superthermality of electrons and concentration of positively/negatively static dust charged particles on the phase shifts of the colliding solitons are also discussed and presented numerically. The results are applicable to space magnetized dusty plasma regimes.

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

    Science.gov (United States)

    Whyte, Dennis

    2013-09-01

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

  10. Influence of the initial parameters of the magnetic field and plasma on the spatial structure of the electric current and electron density in current sheets formed in helium

    Energy Technology Data Exchange (ETDEWEB)

    Ostrovskaya, G. V., E-mail: galya-ostr@mail.ru [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Markov, V. S.; Frank, A. G., E-mail: annfrank@fpl.gpi.ru [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2016-01-15

    The influence of the initial parameters of the magnetic field and plasma on the spatial structure of the electric current and electron density in current sheets formed in helium plasma in 2D and 3D magnetic configurations with X-type singular lines is studied by the methods of holographic interferometry and magnetic measurements. Significant differences in the structures of plasma and current sheets formed at close parameters of the initial plasma and similar configurations of the initial magnetic fields are revealed.

  11. Fast electron generation and transport in a turbulent, magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Stoneking, Matthew Randall [Univ. of Wisconsin, Madison, WI (United States)

    1994-05-01

    The nature of fast electron generation and transport in the Madison Symmetric Torus (MST) reversed field pinch (RFP) is investigated using two electron energy analyzer (EEA) probes and a thermocouple calorimeter. The parallel velocity distribution of the fast electron population is well fit by a drifted Maxwellian distribution with temperature of about 100 eV and drift velocity of about 2 x 106 m/s. Cross-calibration of the EEA with the calorimeter provides a measurement of the fast electron perpendicular temperature of 30 eV, much lower than the parallel temperature, and is evidence that the kinetic dynamo mechanism (KDT) is not operative in MST. The fast electron current is found to match to the parallel current at the edge, and the fast electron density is about 4 x 1011 cm-3 independent of the ratio of the applied toroidal electric field to the critical electric field for runaways. First time measurements of magnetic fluctuation induced particle transport are reported. By correlating electron current fluctuations with radial magnetic fluctuations the transported flux of electrons is found to be negligible outside r/a~0.9, but rises the level of the expected total particle losses inside r/a~0.85. A comparison of the measured diffusion coefficient is made with the ausilinear stochastic diffusion coefficient. Evidence exists that the reduction of the transport is due to the presence of a radial ambipolar electric field of magnitude 500 V/m, that acts to equilibrate the ion and electron transport rates. The convective energy transport associated with the measured particle transport is large enough to account for the observed magnetic fluctuation induced energy transport in MST.

  12. Numerical simulations of a sounding rocket in ionospheric plasma: Effects of magnetic field on the wake formation and rocket potential

    Science.gov (United States)

    Darian, D.; Marholm, S.; Paulsson, J. J. P.; Miyake, Y.; Usui, H.; Mortensen, M.; Miloch, W. J.

    2017-09-01

    The charging of a sounding rocket in subsonic and supersonic plasma flows with external magnetic field is studied with numerical particle-in-cell (PIC) simulations. A weakly magnetized plasma regime is considered that corresponds to the ionospheric F2 layer, with electrons being strongly magnetized, while the magnetization of ions is weak. It is demonstrated that the magnetic field orientation influences the floating potential of the rocket and that with increasing angle between the rocket axis and the magnetic field direction the rocket potential becomes less negative. External magnetic field gives rise to asymmetric wake downstream of the rocket. The simulated wake in the potential and density may extend as far as 30 electron Debye lengths; thus, it is important to account for these plasma perturbations when analyzing in situ measurements. A qualitative agreement between simulation results and the actual measurements with a sounding rocket is also shown.

  13. Thermal instabilities in magnetically confined plasmas - Solar coronal loops

    Science.gov (United States)

    Habbal, S. R.; Rosner, R.

    1979-01-01

    The thermal stability of confined solar coronal structures ('loops') is investigated, following both normal mode and a new, global instability analysis. It is demonstrated that: (1) normal mode analysis shows modes with size scales comparable to that of loops to be unstable, but to be strongly affected by the loop boundary conditions; (2) a global analysis, based upon variation of the total loop energy losses and gains, yields loop stability conditions for global modes dependent upon the coronal loop heating process, with magnetically coupled heating processes giving marginal stability. The connection between the present analysis and the minimum flux corona of Hearn is also discussed.

  14. The Stability of Magnetized Rotating Plasmas with Superthermal Fields

    DEFF Research Database (Denmark)

    Pessah, Martin Elias; Psaltis, Dimitrios

    2005-01-01

    During the last decade it has become evident that the magnetorotational instability is at the heart of the enhanced angular momentum transport in weakly magnetized accretion disks around neutron stars and black holes. In this paper, we investigate the local linear stability of differentially...... modes are subject to instabilities. We find that, for rotating configurations with Keplerian laws, the magnetorotational instability is stabilized at low wavenumbers for toroidal Alfven speeds exceeding the geometric mean of the sound speed and the rotational speed. We discuss the significance of our...

  15. The Plasma Instrument for Magnetic Sounding (PIMS) onboard the Europa Clipper Mission

    Science.gov (United States)

    Westlake, Joseph H.; McNutt, Ralph L.; Kasper, Justin C.; Rymer, Abigail; Case, Anthony; Battista, Corina; Cochrane, Corey; Coren, David; Crew, Alexander; Grey, Matthew; Jia, Xianzhe; Khurana, Krishan; Kim, Cindy; Kivelson, Margaret G.; Korth, Haje; Krupp, Norbert; Paty, Carol; Roussos, Elias; Stevens, Michael; Slavin, James A.; Smith, Howard T.; Saur, Joachim

    2017-10-01

    Europa is embedded in a complex Jovian magnetospheric plasma, which rotates with the tilted planetary field and interacts dynamically with Europa’s ionosphere affecting the magnetic induction signal. Plasma from Io’s temporally varying torus diffuses outward and mixes with the charged particles in Europa’s own torus producing highly variable plasma conditions. Onboard the Europa Clipper spacecraft the Plasma Instrument for Magnetic Sounding (PIMS) works in conjunction with the Interior Characterization of Europa using Magnetometry (ICEMAG) investigation to probe Europa’s subsurface ocean. This investigation exploits currents induced in Europa’s interior by the moon’s exposure to variable magnetic fields in the Jovian system to infer properties of Europa’s subsurface ocean such as its depth, thickness, and conductivity. This technique was successfully applied to Galileo observations and demonstrated that Europa indeed has a subsurface ocean. While these Galileo observations contributed to the renewed interest in Europa, due to limitations in the observations the results raised major questions that remain unanswered. PIMS will greatly refine our understanding of Europa’s global liquid ocean by accounting for contributions to the magnetic field from plasma currents.The Europa Clipper mission is equipped with a sophisticated suite of 9 instruments to study Europa's interior and ocean, geology, chemistry, and habitability from a Jupiter orbiting spacecraft. PIMS on Europa Clipper is a Faraday Cup based plasma instrument whose heritage dates back to the Voyager spacecraft. PIMS will measure the plasma that populates Jupiter’s magnetosphere and Europa’s ionosphere. The science goals of PIMS are to: 1) estimate the ocean salinity and thickness by determining Europa’s magnetic induction response, corrected for plasma contributions; 2) assess mechanisms responsible for weathering and releasing material from Europa’s surface into the atmosphere and

  16. Formation of spiral structures and radial convection in the edge region of a magnetized rotating plasma

    Energy Technology Data Exchange (ETDEWEB)

    Barni, R [Dipartimento di Fisica Occhialini, Universita degli Studi di Milano-Bicocca, p.za della Scienza 3, 20126 Milan (Italy); Riccardi, C [Dipartimento di Fisica Occhialini, Universita degli Studi di Milano-Bicocca, p.za della Scienza 3, 20126 Milan (Italy); Pierre, Th [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France); Leclert, G [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France); Escarguel, A [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France); Guyomarc' h, D [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France); Quotb, K [Laboratoire PIIM, UMR 6633, CNRS et Universite de Provence, 13397 Marseille Cedex 20 (France)

    2005-10-15

    The rotation of a cylindrical plasma column in a magnetic field has been studied in the linear section of the new plasma device Mistral. Under suitable conditions we observe a transition to a turbulent regime characterized by strong, bursty fluctuations at the edge of the column. The detection and the study of the spatio-temporal evolution of structures in the turbulent regime have been performed by means of a new enhanced conditional sampling technique. We have collected evidence of the development of a bent tail emanating from the plasma column. The charged particles inside the structure move along a spiral trajectory resulting in a net radial convection of the plasma to the walls. We show experimentally that a poloidal electric field is present inside the structures leading to the observed outwards radial E x B drift, in agreement with the expectations of recent and past theoretical works.

  17. Controlling Charge and Current Neutralization of an Ion Beam Pulse in a Background Plasma by Application of a Solenoidal Magnetic Field I: Weak Magnetic Field Limit

    Energy Technology Data Exchange (ETDEWEB)

    Kaganovich, I. D., Startsev, E. A., Sefkow, A. B., Davidson, R. C.

    2008-10-10

    Propagation of an intense charged particle beam pulse through a background plasma is a common problem in astrophysics and plasma applications. The plasma can effectively neutralize the charge and current of the beam pulse, and thus provides a convenient medium for beam transport. The application of a small solenoidal magnetic field can drastically change the self-magnetic and self- electric fields of the beam pulse, thus allowing effective control of the beam transport through the background plasma. An analytic model is developed to describe the self-magnetic field of a finite- length ion beam pulse propagating in a cold background plasma in a solenoidal magnetic field. The analytic studies show that the solenoidal magnetic field starts to infuence the self-electric and self-magnetic fields when ωce > ωpeβb, where ωce = eβ/mec is the electron gyrofrequency, ωpe is the electron plasma frequency, and βb = Vb/c is the ion beam velocity relative to the speed of light. This condition typically holds for relatively small magnetic fields (about 100G). Analytical formulas are derived for the effective radial force acting on the beam ions, which can be used to minimize beam pinching. The results of analytic theory have been verified by comparison with the simulation results obtained from two particle-in-cell codes, which show good agreement.

  18. Magnetic Nozzles for Plasma Thrusters: Acceleration, Thrust, and Detachment Mechanisms

    Science.gov (United States)

    2011-10-01

    rneur) = neνw, (3) 0 = − 1 ne d dr ( Tene ) + e dϕ dr − euθeB +me u2θe r , (4) miur dur dr = −edϕ dr −miνiur, (5) meur duθe dr = eurB − νemeuθe −me...together with the Ampere’s law (7) yields the radial momentum equation of the plasma in the form mineur dur dr = − d dr ( Tene + B2 2µ0 ) −mineνiur +mene...in the bulk region corresponds to the known θ-pinch equilibrium[6] Tene +B 2/(2µ0) = const. (19) Then, in the inertial layer, ion convection becomes

  19. A domain-decomposed multi-model plasma simulation of collisionless magnetic reconnection

    Science.gov (United States)

    Datta, I. A. M.; Shumlak, U.; Ho, A.; Miller, S. T.

    2017-10-01

    Collisionless magnetic reconnection is a process relevant to many areas of plasma physics in which energy stored in magnetic fields within highly conductive plasmas is rapidly converted into kinetic and thermal energy. Both in natural phenomena such as solar flares and terrestrial aurora as well as in magnetic confinement fusion experiments, the reconnection process is observed on timescales much shorter than those predicted by a resistive MHD model. As a result, this topic is an active area of research in which plasma models with varying fidelity have been tested in order to understand the proper physics explaining the reconnection process. In this research, a hybrid multi-model simulation employing the Hall-MHD and two-fluid plasma models on a decomposed domain is used to study this problem. The simulation is set up using the WARPXM code developed at the University of Washington, which uses a discontinuous Galerkin Runge-Kutta finite element algorithm and implements boundary conditions between models in the domain to couple their variable sets. The goal of the current work is to determine the parameter regimes most appropriate for each model to maintain sufficient physical fidelity over the whole domain while minimizing computational expense. This work is supported by a Grant from US AFOSR.

  20. Effect of a seed magnetic field on two-fluid plasma Richtmyer-Meshkov instability

    Science.gov (United States)

    Bond, Daryl; Wheatley, Vincent; Samtaney, Ravi; Pullin, Dale

    2016-11-01

    We investigate the effect of a uniform seed magnetic field on the plasma Richtmyer-Meshkov instability (RMI) using two-fluid simulations. These couple sets of conservation equations for the ions and electrons to the full Maxwell's equations. We consider cases where the seed magnetic field is normal to the interface and where the reference Debye length and Larmor radius range from a tenth to a thousandth of the interface perturbation wavelength. In ideal magnetohydrodynamics (MHD), it has been shown that in the presence of such a seed magnetic field, the growth of the RMI is suppressed by the transport of vorticity from the interface by MHD shocks. Our two-fluid plasma simulations reveal that while the RMI is suppressed in the presence of the seed field, the suppression mechanism varies depending on the plasma length-scales. Two-fluid plasma RMI simulations also reveal a secondary, high-wavenumber, electron-driven interface instability. This is not suppressed by the presence of the seed field. This work was partially supported by the KAUST Office of Sponsored Research under Award URF/1/2162-01.

  1. Low-Frequency Electrostatic Ion Surface Waves in Magnetized Electron-Positron Plasmas

    Science.gov (United States)

    Cho, Sang-Hoon; Lee, Hee J.

    The dispersion relations of a surface ion wave propagating on the interface between a warm electron-positron plasma and vacuum when a static magnetic field is directed either normal to the interface (x-wave) or parallel to the wave vector (z-wave) are solved analytically, and the influence of the magnetic field on the ion surface wave is investigated in detail using some numerical work. It is shown that ion surface waves do not exist if the magnetic field is large enough to make the ion gyrofrequency greater than the ion plasma frequency. The attenuation constant of x-waves is more attenuated than that of z-waves and the x-wave is more attenuated as the parameter normalized ion gyrofrequency ζ increases toward 1, but this tendency is reversed for the z-wave. The z-wave does not exist for k2λD2< (ζ/(1-ζ))(p + 1) while the x-wave exists over the whole range of k, where the fractional number p is the ratio between the unperturbed positron and the electron number density. Additionally, we compare the ion surface wave properties of electron-positron plasma with conventional electron-ion plasma.

  2. Role of Radio Frequency and Microwaves in Magnetic Fusion Plasma Research

    Directory of Open Access Journals (Sweden)

    Hyeon K. Park

    2017-10-01

    Full Text Available The role of electromagnetic (EM waves in magnetic fusion plasma—ranging from radio frequency (RF to microwaves—has been extremely important, and understanding of EM wave propagation and related technology in this field has significantly advanced magnetic fusion plasma research. Auxiliary heating and current drive systems, aided by various forms of high-power RF and microwave sources, have contributed to achieving the required steady-state operation of plasmas with high temperatures (i.e., up to approximately 10 keV; 1 eV = 10000 K that are suitable for future fusion reactors. Here, various resonance values and cut-off characteristics of wave propagation in plasmas with a nonuniform magnetic field are used to optimize the efficiency of heating and current drive systems. In diagnostic applications, passive emissions and active sources in this frequency range are used to measure plasma parameters and dynamics; in particular, measurements of electron cyclotron emissions (ECEs provide profile information regarding electron temperature. Recent developments in state-of-the-art 2D microwave imaging systems that measure fluctuations in electron temperature and density are largely based on ECE. The scattering process, phase delays, reflection/diffraction, and the polarization of actively launched EM waves provide us with the physics of magnetohydrodynamic instabilities and transport physics.

  3. Validation of Boltzmann-Poisson Continuum Code with LIF measurements of Plasma Sheath in an Oblique Magnetic Field

    Science.gov (United States)

    Keniley, Shane; Curreli, Davide; Thompson, Derek S.; Henriquez, Miguel F.; Caron, David D.; Jemiolo, Andrew J.; McLaughlin, Jacob W.; Dufor, Mikal T.; Neal, Luke A.; Scime, Earl E.; Siddiqui, M. Umair

    2017-10-01

    Here we present the first fully three-dimensional validation of a 1D3V Boltzmann-Poisson continuum solver against 3D LIF measurements of ion and neutral velocity distribution functions taken in a magnetized plasma sheath. The multi-species full-f plasma model is solved with finite volumes in the phase-space and computes the velocity distribution functions of plasma species, facilitating a direct comparison to LIF data in the magnetic presheath. LIF measurements were taken near an absorbing boundary with a magnetic field obliquely incident to the surface. The plasma model incorporates ionization and charge exchange through a BGK collision operator, with reaction rates computed directly through convolution with the distribution functions. Results clearly display the 3D structure of the magnetized sheath, including acceleration along the ExB direction. Work supported by Scientific Discovery through Advanced Computing (SciDAC) Project on Plasma-Surface Interactions under DE-SC00-08875.

  4. Plasmas fluxes to surfaces for an oblique magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Pitcher, C.S. [Canadian Fusion Fuels Technology Project, Toronto, ON (Canada); Stangeby, P.C.; Elder, J.D. [Toronto Univ., ON (Canada); Bell, M.G.; Kilpatrick, S.J.; Manos, D.M.; Medley, S.S.; Owens, D.K.; Ramsey, A.T.; Ulrickson, M. [Princeton Univ., NJ (United States). Plasma Physics Lab.

    1992-07-01

    The poloidal and toroidal spatial distributions of D{sub {alpha}}, He I and C II emission have been obtained in the vicinity of the TFTR bumper limiter and are compared with models of ion flow to the surface. The distributions are found not to agree with a model (the ``Cosine`` model) which determines the incident flux density using only the parallel fluxes in the scrape-off layer and the projected area of the surface perpendicular to the field lines. In particular, the Cosine model is not able to explain the significant fluxes observed at locations on the surface which are oblique to the magnetic field. It is further shown that these fluxes cannot be explained by the finite Larmor radius of impinging ions. Finally, it is demonstrated, with the use of Monte Carlo codes, that the distributions can be explained by including both parallel and cross-field transport onto the limiter surface.

  5. Plasmas fluxes to surfaces for an oblique magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Pitcher, C.S. (Canadian Fusion Fuels Technology Project, Toronto, ON (Canada)); Stangeby, P.C.; Elder, J.D. (Toronto Univ., ON (Canada)); Bell, M.G.; Kilpatrick, S.J.; Manos, D.M.; Medley, S.S.; Owens, D.K.; Ramsey, A.T.; Ulrickson, M. (Princeton Univ., NJ (United States). Plasma Physics Lab.)

    1992-07-01

    The poloidal and toroidal spatial distributions of D{sub {alpha}}, He I and C II emission have been obtained in the vicinity of the TFTR bumper limiter and are compared with models of ion flow to the surface. The distributions are found not to agree with a model (the Cosine'' model) which determines the incident flux density using only the parallel fluxes in the scrape-off layer and the projected area of the surface perpendicular to the field lines. In particular, the Cosine model is not able to explain the significant fluxes observed at locations on the surface which are oblique to the magnetic field. It is further shown that these fluxes cannot be explained by the finite Larmor radius of impinging ions. Finally, it is demonstrated, with the use of Monte Carlo codes, that the distributions can be explained by including both parallel and cross-field transport onto the limiter surface.

  6. Asymptotic-preserving Lagrangian approach for modeling anisotropic transport in magnetized plasmas

    Science.gov (United States)

    Chacon, Luis; Del-Castillo-Negrete, Diego

    2012-03-01

    Modeling electron transport in magnetized plasmas is extremely challenging due to the extreme anisotropy between parallel (to the magnetic field) and perpendicular directions (the transport-coefficient ratio χ/χ˜10^10 in fusion plasmas). Recently, a novel Lagrangian Green's function method has been proposedfootnotetextD. del-Castillo-Negrete, L. Chac'on, PRL, 106, 195004 (2011); D. del-Castillo-Negrete, L. Chac'on, Phys. Plasmas, submitted (2011) to solve the local and non-local purely parallel transport equation in general 3D magnetic fields. The approach avoids numerical pollution, is inherently positivity-preserving, and is scalable algorithmically (i.e., work per degree-of-freedom is grid-independent). In this poster, we discuss the extension of the Lagrangian Green's function approach to include perpendicular transport terms and sources. We present an asymptotic-preserving numerical formulation, which ensures a consistent numerical discretization temporally and spatially for arbitrary χ/χ ratios. We will demonstrate the potential of the approach with various challenging configurations, including the case of transport across a magnetic island in cylindrical geometry.

  7. Sub-Pixel Magnetic Field and Plasma Dynamics Derived from Photospheric Spectral Data

    Science.gov (United States)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2017-08-01

    Current high-resolution observations of the photosphere show small dynamic features at the resolving limit during emerging flux events. However, line-of-sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. Using a new method with spectrographic images, we quantify distortions in photospheric absorption (or emission) lines caused by sub-pixel magnetic field and plasma dynamics in the vicinity of active regions and emerging flux events. Absorption lines—quantified by their displacement, width, asymmetry, and peakedness—have previously been used with Stokes I images from SOLIS/VSM to relate line distortions with sub-pixel plasma dynamics driven by solar flares or small-scale flux ropes. The method is extended to include the full Stokes parameters and relate inferred sub-pixel dynamics with small-scale magnetic fields. Our analysis is performed on several sets of spectrographic images taken by SOLIS/VSM while observing eruptive and non-eruptive active regions. We discuss the results of this application and their relevance for understanding magnetic fields signatures and coupled plasma properties on sub-pixel scales.

  8. 3D MHD Simulations of Laser Plasma Guiding in Curved Magnetic Field

    Science.gov (United States)

    Roupassov, S.; Rankin, R.; Tsui, Y.; Capjack, C.; Fedosejevs, R.

    1999-11-01

    The guiding and confinement of laser produced plasma in a curved magnetic field has been investigated numerically. These studies were motivated by experiments on pulsed laser deposition of diamond-like films [1] in which a 1kG magnetic field in a curved solenoid geometry was utilized to steer a carbon plasma around a curved trajectory and thus to separate it from unwanted macroparticles produced by the laser ablation. The purpose of the modeling was to characterize the plasma dynamics during the propagation through the magnetic guide field and to investigate the effect of different magnetic field configurations. A 3D curvilinear ADI code developed on the basis of an existing Cartesian code [2] was employed to simulate the underlying resistive one-fluid MHD model. Issues such as large regions of low background density and nonreflective boundary conditions were addressed. Results of the simulations in a curved guide field will be presented and compared to experimental results. [1] Y.Y. Tsui, D. Vick and R. Fedosejevs, Appl. Phys. Lett. 70 (15), pp. 1953-57, 1997. [2] R. Rankin, and I. Voronkov, in "High Performance Computing Systems and Applications", pp. 59-69, Kluwer AP, 1998.

  9. Phase mixing of Alfvén waves in axisymmetric non-reflective magnetic plasma configurations

    Science.gov (United States)

    Petrukhin, N. S.; Ruderman, M. S.; Shurgalina, E. G.

    2018-02-01

    We study damping of phase-mixed Alfvén waves propagating in non-reflective axisymmetric magnetic plasma configurations. We derive the general equation describing the attenuation of the Alfvén wave amplitude. Then we applied the general theory to a particular case with the exponentially divergent magnetic field lines. The condition that the configuration is non-reflective determines the variation of the plasma density along the magnetic field lines. The density profiles exponentially decreasing with the height are not among non-reflective density profiles. However, we managed to find non-reflective profiles that fairly well approximate exponentially decreasing density. We calculate the variation of the total wave energy flux with the height for various values of shear viscosity. We found that to have a substantial amount of wave energy dissipated at the lower corona, one needs to increase shear viscosity by seven orders of magnitude in comparison with the value given by the classical plasma theory. An important result that we obtained is that the efficiency of the wave damping strongly depends on the density variation with the height. The stronger the density decrease, the weaker the wave damping is. On the basis of this result, we suggested a physical explanation of the phenomenon of the enhanced wave damping in equilibrium configurations with exponentially diverging magnetic field lines.

  10. Interpreting the behavior of a quarter-wave transmission line resonator in a magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Gogna, G. S., E-mail: gurusharansingh.gogna@gmail.com; Turner, M. M. [NCPST, School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Karkari, S. K., E-mail: skarkari@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat (India)

    2014-12-15

    The quarter wave resonator immersed in a strongly magnetized plasma displays two possible resonances occurring either below or above its resonance frequency in vacuum, f{sub o}. This fact was demonstrated in our recent articles [G. S. Gogna and S. K. Karkari, Appl. Phys. Lett. 96, 151503 (2010); S. K. Karkari, G. S. Gogna, D. Boilson, M. M. Turner, and A. Simonin, Contrib. Plasma Phys. 50(9), 903 (2010)], where the experiments were carried out over a limited range of magnetic fields at a constant electron density, n{sub e}. In this paper, we present the observation of dual resonances occurring over the frequency scan and find that n{sub e} calculated by considering the lower resonance frequency is 25%–30% smaller than that calculated using the upper resonance frequency with respect to f{sub o}. At a given magnetic field strength, the resonances tend to shift away from f{sub o} as the background density is increased. The lower resonance tends to saturate when its value approaches electron cyclotron frequency, f{sub ce}. Interpretation of these resonance conditions are revisited by examining the behavior of the resonance frequency response as a function of n{sub e}. A qualitative discussion is presented which highlights the practical application of the hairpin resonator for interpreting n{sub e} in a strongly magnetized plasma.

  11. Spectroscopic ion beam imaging for investigations into magnetic field mapping of a plasma

    Science.gov (United States)

    Demers, D. R.; Schoch, P. M.; Radke, R. J.; Anderson, J. K.; Craig, D.; Hartog, D. J. Den

    2003-03-01

    The trajectory of an ion beam as it passes through a magnetically confined plasma is determined by the ion mass, energy, and charge state, and the magnetic field structure. In undergraduate physics laboratories, students use a measure of beam deflection in a well-defined magnetic field to determine the charge-to-mass ratio of a particle. The complementary analysis is equally valid; the field may be determined given a known charge-to-mass ratio. Additional complexity is introduced in a spatially nonuniform, time-varying magnetic field, such as that of a plasma. The technique of field mapping via spectral imaging is being developed with a heavy ion beam probe on the Madison Symmetric Torus. Technical issues, such as choice of wavelengths, optics, viewing geometry, and imaging hardware, are being addressed. Calculations indicate that beam emission is brighter than background bremsstrahlung for several transitions of interest. However, a wavelength region containing lines from the beam ions, but free of atomic lines from the plasma, remains to be identified.

  12. Dust-acoustic solitary waves in a magnetized dusty plasma with nonthermal electrons and trapped ions

    CERN Document Server

    Misra, A P

    2014-01-01

    The nonlinear theory of electrostatic dust-acoustic (DA) waves in a magnetized dusty plasma consisting of negatively charged mobile dusts, nonthermal fast electrons and trapped ions with vortex-like distribution is revisited. Previous theory in the literature [Phys. Plasmas {\\bf 20}, 104505 (2013)] is rectified and put forward to include the effects of the external magnetic field, the adiabatic pressure of charged dusts as well as the obliqueness of propagation to the magnetic field. Using the reductive perturbation technique, a Korteweg-de Vries (KdV)-like equation is derived which governs the dynamics of the small-amplitude solitary waves in a magnetized dusty nonthermal plasma. It is found that due to the dust thermal pressure, there exists a critical value $(\\beta_c)$ of the nothermal parameter $\\beta (>1)$, denoting the percentage of energetic electrons, below which the DA solitary waves cease to propagate. The soliton solution (travelling wave) of the KdV-like equation is obtained, and is shown to be on...

  13. Plasma immersion ion implantation and deposition of DLC coating for modification of orthodontic magnets

    Energy Technology Data Exchange (ETDEWEB)

    Wongsarat, W. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sarapirom, S. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); National Metal and Materials Technology Center, 114 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, Pathumthani, Bangkok 12120 (Thailand); Aukkaravittayapun, S. [National Metal and Materials Technology Center, 114 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, Pathumthani, Bangkok 12120 (Thailand); Jotikasthira, D. [Department of Odontology-Oral Pathology, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200 (Thailand); Boonyawan, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2012-02-01

    This study was aimed to use the plasma immersion ion implantation and deposition (PIII-D) technique to form diamond-like carbon (DLC) thin films on orthodontic magnets to solve the corrosion problem. To search for the optimal material modification effect, PIII-D conditions including gases, processing time, and pulsing mode were varied. The formation of DLC films was confirmed and characterized with Raman spectra. The intensity of the remnant magnetic field of the magnets and the hardness, adhesion and thickness of the thin films were then measured. A corrosion test was carried out using clinic dental fluid. Improved benefits including a satisfying hardness, adhesion, remnant magnetic strength and corrosion resistance of the DLC coating could be achieved by using a higher interrupting time ratio and shorter processing time.

  14. Developed turbulence and nonlinear amplification of magnetic fields in laboratory and astrophysical plasmas.

    Science.gov (United States)

    Meinecke, Jena; Tzeferacos, Petros; Bell, Anthony; Bingham, Robert; Clarke, Robert; Churazov, Eugene; Crowston, Robert; Doyle, Hugo; Drake, R Paul; Heathcote, Robert; Koenig, Michel; Kuramitsu, Yasuhiro; Kuranz, Carolyn; Lee, Dongwook; MacDonald, Michael; Murphy, Christopher; Notley, Margaret; Park, Hye-Sook; Pelka, Alexander; Ravasio, Alessandra; Reville, Brian; Sakawa, Youichi; Wan, Willow; Woolsey, Nigel; Yurchak, Roman; Miniati, Francesco; Schekochihin, Alexander; Lamb, Don; Gregori, Gianluca

    2015-07-07

    The visible matter in the universe is turbulent and magnetized. Turbulence in galaxy clusters is produced by mergers and by jets of the central galaxies and believed responsible for the amplification of magnetic fields. We report on experiments looking at the collision of two laser-produced plasma clouds, mimicking, in the laboratory, a cluster merger event. By measuring the spectrum of the density fluctuations, we infer developed, Kolmogorov-like turbulence. From spectral line broadening, we estimate a level of turbulence consistent with turbulent heating balancing radiative cooling, as it likely does in galaxy clusters. We show that the magnetic field is amplified by turbulent motions, reaching a nonlinear regime that is a precursor to turbulent dynamo. Thus, our experiment provides a promising platform for understanding the structure of turbulence and the amplification of magnetic fields in the universe.

  15. Characteristics of magnetic island formation due to resistive interchange instability in helical plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, R.; Matsumoto, Y.; Itagaki, M.; Oikawa, S. [Graduate School of Hokkaido University, Sapporo 060-8628 (Japan); Watanabe, K. Y.; Sato, M. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

    2014-05-15

    Focusing attention on the magnetic island formation, we investigate the characteristics of the resistive interchange magnetohydrodynamics instabilities, which would limit a high beta operational regime in helical type fusion reactors. An introduction of a new index, i.e., the ratio of the magnetic fluctuation level to the radial displacement, enables us to make a systematic analysis on the magnetic island formation in the large helical device-like plasmas during the linear growth phase; (i) the interchange instability with the second largest growth rate makes the magnetic island larger than that with the largest growth rate when the amplitude of the radial displacement in both cases is almost the same as each other; (ii) applied to a typical tearing instability, the index is smaller than that for the interchange instability with the second largest growth rate.

  16. The magnetic field application for the gas discharge plasma control in processes of surface coating and modification

    Science.gov (United States)

    Asadullin, T. Ya; Galeev, I. G.

    2017-01-01

    In this paper the method of magnetic field application to control the gas discharge plasma effect on the various surfaces in processes of surface coating and modification is considered. The magnetic field directed perpendicular to the direction of electric current in the gas discharge plasma channel is capable to reject this plasma channel due to action of Lorentz force on the moving electrically charged particles [1,2]. The three-dimensional spatial structure of magnetic field is created by system of necessary quantity of the magnets located perpendicular to the direction of course of electric current in the gas-discharge plasma channel. The formation of necessary spatial distribution of magnetic field makes possible to obtain a required distribution of plasma parameters near the processed surfaces. This way of the plasma channel parameters spatial distribution management is the most suitable for application in processes of plasma impact on a surface of irregular shape and in cases when the selective impact of plasma on a part of a surface of a product is required. It is necessary to apply automated computer management of the process parameters [3] to the most effective plasma impact.

  17. Helium temperature measurements in a hot filament magnetic mirror plasma using high resolution Doppler spectroscopy

    Science.gov (United States)

    Knott, S.; McCarthy, P. J.; Ruth, A. A.

    2016-09-01

    Langmuir probe and spectroscopic diagnostics are used to routinely measure electron temperature and density over a wide operating range in a reconfigured Double Plasma device at University College Cork, Ireland. The helium plasma, generated through thermionic emission from a negatively biased tungsten filament, is confined by an axisymmetric magnetic mirror configuration using two stacks of NdFeB permanent magnets, each of length 20 cm and diameter 3 cm placed just outside the 15 mm water cooling jacket enclosing a cylindrical vacuum vessel of internal diameter 25 cm. Plasma light is analysed using a Fourier Transform-type Bruker spectrometer with a highest achievable resolution of 0.08 cm-1 . In the present work, the conventional assumption of room temperature ions in the analysis of Langmuir probe data from low temperature plasmas is examined critically using Doppler spectroscopy of the 468.6 nm He II line. Results for ion temperatures obtained from spectroscopic data for a variety of engineering parameters (discharge voltage, gas pressure and plasma current) will be presented.

  18. Three-dimensional rotational plasma flows near solid surfaces in an axial magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Gorshunov, N. M., E-mail: gorshunov-nm@nrcki.ru; Potanin, E. P., E-mail: potanin45@yandex.ru [National Research Center Kurchatov Institute (Russian Federation)

    2016-11-15

    A rotational flow of a conducting viscous medium near an extended dielectric disk in a uniform axial magnetic field is analyzed in the magnetohydrodynamic (MHD) approach. An analytical solution to the system of nonlinear differential MHD equations of motion in the boundary layer for the general case of different rotation velocities of the disk and medium is obtained using a modified Slezkin–Targ method. A particular case of a medium rotating near a stationary disk imitating the end surface of a laboratory device is considered. The characteristics of a hydrodynamic flow near the disk surface are calculated within the model of a finite-thickness boundary layer. The influence of the magnetic field on the intensity of the secondary flow is studied. Calculations are performed for a weakly ionized dense plasma flow without allowance for the Hall effect and plasma compressibility. An MHD flow in a rotating cylinder bounded from above by a retarding cap is considered. The results obtained can be used to estimate the influence of the end surfaces on the main azimuthal flow, as well as the intensities of circulating flows in various devices with rotating plasmas, in particular, in plasma centrifuges and laboratory devices designed to study instabilities of rotating plasmas.

  19. The impact of Hall physics on magnetized high energy density plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A. [Cornell University, Ithaca, New York 14853 (United States)

    2014-05-15

    Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (n{sub e} ∼ 10{sup 19} cm{sup −3}). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (∼1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10 T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches)

  20. Ring-averaged ion velocity distribution function probe for laboratory magnetized plasma experiment

    Science.gov (United States)

    Kawamori, Eiichirou; Chen, Jinting; Lin, Chiahsuan; Lee, Zongmau

    2017-10-01

    Ring-averaged velocity distribution function of ions at a fixed guiding center position is a fundamental quantity in the gyrokinetic plasma physics. We have developed a diagnostic tool for the ring averaged velocity distribution function of ions for laboratory plasma experiments, which is named as the ring-averaged ion distribution function probe (RIDFP). The RIDFP is a set of ion collectors for different velocities. It is designed to be immersed in magnetized plasmas and achieves momentum selection of incoming ions by the selection of the ion Larmor radii. To nullify the influence of the sheath potential surrounding the RIDFP on the orbits of the incoming ions, the electrostatic potential of the RIDFP body is automatically adjusted to coincide with the space potential of the target plasma with the use of an emissive probe and a voltage follower. The developed RIDFP successfully measured the equilibrium ring-averaged velocity distribution function of a laboratory magnetized plasma, which was in accordance with the Maxwellian distribution having an ion temperature of 0.2 eV.

  1. Ring-averaged ion velocity distribution function probe for laboratory magnetized plasma experiment.

    Science.gov (United States)

    Kawamori, Eiichirou; Chen, Jinting; Lin, Chiahsuan; Lee, Zongmau

    2017-10-01

    Ring-averaged velocity distribution function of ions at a fixed guiding center position is a fundamental quantity in the gyrokinetic plasma physics. We have developed a diagnostic tool for the ring averaged velocity distribution function of ions for laboratory plasma experiments, which is named as the ring-averaged ion distribution function probe (RIDFP). The RIDFP is a set of ion collectors for different velocities. It is designed to be immersed in magnetized plasmas and achieves momentum selection of incoming ions by the selection of the ion Larmor radii. To nullify the influence of the sheath potential surrounding the RIDFP on the orbits of the incoming ions, the electrostatic potential of the RIDFP body is automatically adjusted to coincide with the space potential of the target plasma with the use of an emissive probe and a voltage follower. The developed RIDFP successfully measured the equilibrium ring-averaged velocity distribution function of a laboratory magnetized plasma, which was in accordance with the Maxwellian distribution having an ion temperature of 0.2 eV.

  2. Effect of magnetic quantization on ion acoustic waves ultra-relativistic dense plasma

    Science.gov (United States)

    Javed, Asif; Rasheed, A.; Jamil, M.; Siddique, M.; Tsintsadze, N. L.

    2017-11-01

    In this paper, we have studied the influence of magnetic quantization of orbital motion of the electrons on the profile of linear and nonlinear ion-acoustic waves, which are propagating in the ultra-relativistic dense magneto quantum plasmas. We have employed both Thomas Fermi and Quantum Magneto Hydrodynamic models (along with the Poisson equation) of quantum plasmas. To investigate the large amplitude nonlinear structure of the acoustic wave, Sagdeev-Pseudo-Potential approach has been adopted. The numerical analysis of the linear dispersion relation and the nonlinear acoustic waves has been presented by drawing their graphs that highlight the effects of plasma parameters on these waves in both the linear and the nonlinear regimes. It has been noticed that only supersonic ion acoustic solitary waves can be excited in the above mentioned quantum plasma even when the value of the critical Mach number is less than unity. Both width and depth of Sagdeev potential reduces on increasing the magnetic quantization parameter η. Whereas the amplitude of the ion acoustic soliton reduces on increasing η, its width appears to be directly proportional to η. The present work would be helpful to understand the excitation of nonlinear ion-acoustic waves in the dense astrophysical environments such as magnetars and in intense-laser plasma interactions.

  3. Magnetospheric plasma boundaries: a test of the frozen-in magnetic field theorem

    Directory of Open Access Journals (Sweden)

    R. Lundin

    2005-10-01

    Full Text Available The notion of frozen-in magnetic field originates from H. Alfvén, the result of a work on electromagnetic-hydrodynamic waves published in 1942. After that, the notion of frozen-in magnetic field, or ideal MHD, has become widely used in space plasma physics. The controversy on the applicability of ideal MHD started in the late 1950s and has continued ever since. The applicability of ideal MHD is particularly interesting in regions where solar wind plasma may cross the magnetopause and access the magnetosphere. It is generally assumed that a macroscopic system can be described by ideal MHD provided that the violations of ideal MHD are sufficiently small-sized near magnetic x-points (magnetic reconnection. On the other hand, localized departure from ideal MHD also enables other processes to take place, such that plasma may cross the separatrix and access neighbouring magnetic flux tubes. It is therefore important to be able to quantify from direct measurements ideal MHD, a task that has turned out to be a major challenge.

    An obvious test is to compare the perpendicular electric field with the plasma drift, i.e. to test if E=–v×B. Yet another aspect is to rule out the existence of parallel (to B electric fields. These two tests have been subject to extensive research for decades. However, the ultimate test of the "frozen-in" condition, based on measurement data, is yet to be identified. We combine Cluster CIS-data and FGM-data, estimating the change in magnetic flux (δB/δt and the curl of plasmav×B(∇×(v×B, the terms in the "frozen-in equation". Our test suggests that ideal MHD applies in a macroscopic sense in major parts of the outer magnetosphere, for instance, in the external cusp and in the high-latitude magnetosheath. However, we also find significant departures from ideal MHD, as expected on smaller scales, but also on larger scales, near

  4. Magnetospheric plasma boundaries: a test of the frozen-in magnetic field theorem

    Directory of Open Access Journals (Sweden)

    R. Lundin

    2005-10-01

    Full Text Available The notion of frozen-in magnetic field originates from H. Alfvén, the result of a work on electromagnetic-hydrodynamic waves published in 1942. After that, the notion of frozen-in magnetic field, or ideal MHD, has become widely used in space plasma physics. The controversy on the applicability of ideal MHD started in the late 1950s and has continued ever since. The applicability of ideal MHD is particularly interesting in regions where solar wind plasma may cross the magnetopause and access the magnetosphere. It is generally assumed that a macroscopic system can be described by ideal MHD provided that the violations of ideal MHD are sufficiently small-sized near magnetic x-points (magnetic reconnection. On the other hand, localized departure from ideal MHD also enables other processes to take place, such that plasma may cross the separatrix and access neighbouring magnetic flux tubes. It is therefore important to be able to quantify from direct measurements ideal MHD, a task that has turned out to be a major challenge. An obvious test is to compare the perpendicular electric field with the plasma drift, i.e. to test if E=–v×B. Yet another aspect is to rule out the existence of parallel (to B electric fields. These two tests have been subject to extensive research for decades. However, the ultimate test of the "frozen-in" condition, based on measurement data, is yet to be identified. We combine Cluster CIS-data and FGM-data, estimating the change in magnetic flux (δB/δt and the curl of plasma –v×B(∇×(v×B, the terms in the "frozen-in equation". Our test suggests that ideal MHD applies in a macroscopic sense in major parts of the outer magnetosphere, for instance, in the external cusp and in the high-latitude magnetosheath. However, we also find significant departures from ideal MHD, as expected on smaller scales, but also on larger scales, near the cusp and in the magnetosphere-boundary layer. We discuss the importance of these

  5. Increasing the magnetic helicity content of a plasma by pulsing a magnetized source.

    Science.gov (United States)

    Woodruff, S; Stallard, B W; McLean, H S; Hooper, E B; Bulmer, R; Cohen, B I; Hill, D N; Holcomb, C T; Moller, J; Wood, R D

    2004-11-12

    By operating a magnetized coaxial gun in a pulsed mode it is possible to produce large voltage pulses of duration approximately 500 mus while reaching a few kV, giving a discrete input of helicity into a spheromak. In the sustained spheromak physics experiment (SSPX), it is observed that pulsing serves to nearly double the stored magnetic energy and double the temperature. We discuss these results by comparison with 3D MHD simulations of the same phenomenon.

  6. Long-range magnetic fields in the ground state of the Standard Model plasma.

    Science.gov (United States)

    Boyarsky, Alexey; Ruchayskiy, Oleg; Shaposhnikov, Mikhail

    2012-09-14

    In thermal equilibrium the ground state of the plasma of Standard Model particles is determined by temperature and exactly conserved combinations of baryon and lepton numbers. We show that at nonzero values of the global charges a translation invariant and homogeneous state of the plasma becomes unstable and the system transits into a new equilibrium state, containing a large-scale magnetic field. The origin of this effect is the parity-breaking character of weak interactions and chiral anomaly. This situation could occur in the early Universe and may play an important role in its subsequent evolution.

  7. Long-range magnetic fields in the ground state of the Standard Model plasma

    CERN Document Server

    Boyarsky, Alexey; Shaposhnikov, Mikhail

    2012-01-01

    In thermal equilibrium the ground state of the plasma of Standard Model particles is determined by temperature and exactly conserved combinations of baryon and lepton numbers. We show that at non-zero values of the global charges a translation invariant and homogeneous state of the plasma becomes unstable and the system transits into a new state, containing a large-scale magnetic field. The origin of this effect is the parity-breaking character of weak interactions and chiral anomaly. This situation can occur in the early Universe and may play an important role in its subsequent evolution.

  8. Properties of density of modes in one dimensional magnetized plasma photonic crystals

    Science.gov (United States)

    Prasad, S.; Sharma, Y.; Shukla, S.; Singh, V.

    2016-03-01

    The electromagnetic density of modes in a finite one dimensional magnetized plasma photonic crystal is computed using Wigner time approach. Structural parameters are varied to observe its effect on the density of modes. It is found that cyclotron frequency, collision frequency, incident angle, dielectric constant of constituent material, and filling factor of plasma strongly influence the value of density of modes on the band gap edges and in the mid frequency. It is observed that the value of density of modes at the left edge of the band gap is always higher than those at the right edge and in the midpoint of the band gap.

  9. Density Measurements in Low Pressure, Weakly Magnetized, RF Plasmas: Experimental Verification of the Sheath Expansion Effect

    Directory of Open Access Journals (Sweden)

    Yunchao Zhang

    2017-07-01

    Full Text Available This experimental study shows the validity of Sheridan's method in determining plasma density in low pressure, weakly magnetized, RF plasmas using ion saturation current data measured by a planar Langmuir probe. The ion density derived from Sheridan's method which takes into account the sheath expansion around the negatively biased probe tip, presents a good consistency with the electron density measured by a cylindrical RF-compensated Langmuir probe using the Druyvesteyn theory. The ion density obtained from the simplified method which neglects the sheath expansion effect, overestimates the true density magnitude, e.g., by a factor of 3 to 12 for the present experiment.

  10. Nonthermal plasmas around black holes, relevant collective modes, new configurations, and magnetic field amplification

    Energy Technology Data Exchange (ETDEWEB)

    Coppi, B., E-mail: coppi@mit.edu [Massachusetts Institute of Technology (United States)

    2017-03-15

    The radiation emission from Shining Black Holes is most frequently observed to have nonthermal features. It is therefore appropriate to consider relevant collective processes in plasmas surrounding black holes that contain high energy particles with nonthermal distributions in momentum space. A fluid description with significant temperature anisotropies is the simplest relevant approach. These anisotropies are shown to have a critical influence on: (a) the existence and characteristics of stationary plasma and field ring configurations, (b) the excitation of “thermo-gravitational modes” driven by temperature anisotropies and gradients that involve gravity and rotation, (c) the generation of magnetic fields over macroscopic scale distances, and (d) the transport of angular momentum.

  11. Analytical model of particle and heat flux collection by dust immersed in dense magnetized plasmas

    Science.gov (United States)

    Vignitchouk, L.; Ratynskaia, S.; Tolias, P.

    2017-10-01

    A comprehensive analytical description is presented for the particle and heat fluxes collected by dust in dense magnetized plasmas. Compared to the widely used orbital motion limited theory, the suppression of cross-field transport leads to a strong reduction of the electron fluxes, while ion collection is inhibited by thin-sheath effects and the formation of a potential overshoot along the field lines. As a result, the incoming heat flux loses its sensitivity to the floating potential, thereby diminishing the importance of electron emission processes in dust survivability. Numerical simulations implementing the new model for ITER-like detached divertor plasmas predict a drastic enhancement of the dust lifetime.

  12. Robustness of the filamentation instability for asymmetric plasma shells collision in arbitrarily oriented magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Bret, A. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain and Instituto de Investigaciones Energticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain)

    2013-10-15

    The filamentation instability triggered when two counter streaming plasma shells overlap appears to be the main mechanism by which collisionless shocks are generated. It has been known for long that a flow aligned magnetic field can completely suppress this instability. In a recent paper [Phys. Plasmas 18, 080706 (2011)], it was demonstrated in two dimensions that for the case of two cold, symmetric, relativistically colliding shells, such cancellation cannot occur if the field is not perfectly aligned. Here, this result is extended to the case of two asymmetric shells. The filamentation instability appears therefore as an increasingly robust mechanism to generate shocks.

  13. Kinetic approach to the helium transport in a divertor plasma along the magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Krasheninnikov, S.I.; Soboleva, T.K. (I.V. Kurchatov Inst. of Atomic Energy, Ploshchad akademika Kurchatova, 123281 Moscos (SU)); Gac, K. (Instytut Fizyki Plazmy i Laserowej Mikrosyntezy, Warsaw (Poland))

    1990-11-01

    This paper considers impurity (helium) ion transport kinetics in a tokamak divertor along magnetic field lines, both analytically and numerically, for the case when the ratio of collisional mean-free-path to the characteristic length of plasma parameter variation is not too small. To obtain the numerical solution of the kinetics equation, the stochastic modeling method is used. For International Thermonuclear Experimental Reactor (ITER) divertor plasma conditions, the influence of thermal force on helium ions is expected to be decreased considerably. As a result, the helium ion flux toward the divertor plates may be significantly enhanced compared to that predicted by the hydrodynamics approach.

  14. Density measurements in low pressure, weakly magnetized, RF plasmas: experimental verification of the sheath expansion effect

    Science.gov (United States)

    Zhang, Yunchao; Charles, Christine; Boswell, Roderick W.

    2017-07-01

    This experimental study shows the validity of Sheridan's method in determining plasma density in low pressure, weakly magnetized, RF plasmas using ion saturation current data measured by a planar Langmuir probe. The ion density derived from Sheridan's method which takes into account the sheath expansion around the negatively biased probe tip, presents a good consistency with the electron density measured by a cylindrical RF-compensated Langmuir probe using the Druyvesteyn theory. The ion density obtained from the simplified method which neglects the sheath expansion effect, overestimates the true density magnitude, e.g., by a factor of 3 to 12 for the present experiment.

  15. Stochastic Fermi Energization of Coronal Plasma during Explosive Magnetic Energy Release

    Energy Technology Data Exchange (ETDEWEB)

    Pisokas, Theophilos; Vlahos, Loukas; Isliker, Heinz; Tsiolis, Vassilis [Department of Physics, Aristotle University of Thessaloniki GR-52124 Thessaloniki (Greece); Anastasiadis, Anastasios [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens GR-15236 Penteli (Greece)

    2017-02-01

    The aim of this study is to analyze the interaction of charged particles (ions and electrons) with randomly formed particle scatterers (e.g., large-scale local “magnetic fluctuations” or “coherent magnetic irregularities”) using the setup proposed initially by Fermi. These scatterers are formed by the explosive magnetic energy release and propagate with the Alfvén speed along the irregular magnetic fields. They are large-scale local fluctuations ( δB / B ≈ 1) randomly distributed inside the unstable magnetic topology and will here be called Alfvénic Scatterers (AS). We constructed a 3D grid on which a small fraction of randomly chosen grid points are acting as AS. In particular, we study how a large number of test particles evolves inside a collection of AS, analyzing the evolution of their energy distribution and their escape-time distribution. We use a well-established method to estimate the transport coefficients directly from the trajectories of the particles. Using the estimated transport coefficients and solving the Fokker–Planck equation numerically, we can recover the energy distribution of the particles. We have shown that the stochastic Fermi energization of mildly relativistic and relativistic plasma can heat and accelerate the tail of the ambient particle distribution as predicted by Parker and Tidman and Ramaty. The temperature of the hot plasma and the tail of the energetic particles depend on the mean free path ( λ {sub sc}) of the particles between the scatterers inside the energization volume.

  16. Nonlocal weakly relativistic permittivity tensor of magnetized plasma near electron cyclotron resonances

    Science.gov (United States)

    Sakharov, A. S.

    2017-11-01

    Compact expressions are derived for the nonlocal permittivity tensor of weakly relativistic plasma in a 2D nonuniform magnetic field near the resonances at the second harmonic of the electron cyclotron frequency for an extraordinary wave and at the first harmonic for an ordinary wave. It is shown that the wave equation with allowance for the obtained thermal correction to the permittivity tensor in the form of a differential operator in transverse (with respect to the external magnetic field) coordinates possesses an integral in the form of the energy conservation law.

  17. Study of fractal features of magnetized plasma through an MHD shell model

    Science.gov (United States)

    Domínguez, M.; Nigro, G.; Muñoz, V.; Carbone, V.

    2017-07-01

    A magnetohydrodynamic (MHD) shell model is used to describe the dissipative events which take place in magnetized plasmas. A scatter plot box-counting fractal dimension D is calculated for the time series of the magnetic energy dissipation rate obtained in the MHD shell model, and the correlation between D and the energy dissipation rate is analyzed. We show that, depending on the values of the viscosity and the diffusivity, the fractal dimension and the occurrence of bursts exhibit correlations similar to those observed in previous studies.

  18. The effect of sheared toroidal rotation on pressure driven magnetic islands in toroidal plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hegna, C. C. [Departments of Engineering Physics and Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2016-05-15

    The impact of sheared toroidal rotation on the evolution of pressure driven magnetic islands in tokamak plasmas is investigated using a resistive magnetohydrodynamics model augmented by a neoclassical Ohm's law. Particular attention is paid to the asymptotic matching data as the Mercier indices are altered in the presence of sheared flow. Analysis of the nonlinear island Grad-Shafranov equation shows that sheared flows tend to amplify the stabilizing pressure/curvature contribution to pressure driven islands in toroidal tokamaks relative to the island bootstrap current contribution. As such, sheared toroidal rotation tends to reduce saturated magnetic island widths.

  19. A dynamic analysis of the magnetized plasma sheath in a collisionless scenario with ion sources

    Science.gov (United States)

    Adhikari, S.; Moulick, R.; Goswami, K. S.

    2017-08-01

    The influence of the forces that control the ion dynamics inside a magnetized plasma sheath under collisionless conditions is analyzed. Considering the ionization, the effects of the variation of field strength and the inclination angle on the force fields inside the sheath are studied. The pitch length and pitch angle for the particle velocity fields are also calculated and have been found to vary widely with the inclination angle and the strength of the magnetic field. The role of the Lorentz force and energy acquired by the ions while moving towards the wall is highlighted. A comparison between two different ion sources has also been foregrounded.

  20. Stimulated Raman forward scattering of a laser in a plasma with transverse magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Hassoon, Khaleel; Salih, Hyder [School of Applied Sciences, University of Technology, Baghdad (Iraq); Tripathi, V K [Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)], E-mail: kihassoun@yahoo.com

    2009-12-15

    The effect of a transverse static magnetic field on stimulated Raman forward scattering (SRFS) of a laser in a plasma is studied. The x-mode excites an upper hybrid wave and two localized Stokes/anti-Stokes sidebands. The laser and the sideband exert a ponderomotive force on electrons driving the upper hybrid wave. The latter couples with the pump to drive the sidebands. The growth rate of SRFS monotonically increases by applying a static magnetic field. It also increases with the pump amplitude; however, the dependence is slower than linear.

  1. Stimulated Raman forward scattering of a laser in a plasma with transverse magnetic field

    Science.gov (United States)

    Hassoon, Khaleel; Salih, Hyder; Tripathi, V. K.

    2009-12-01

    The effect of a transverse static magnetic field on stimulated Raman forward scattering (SRFS) of a laser in a plasma is studied. The x-mode excites an upper hybrid wave and two localized Stokes/anti-Stokes sidebands. The laser and the sideband exert a ponderomotive force on electrons driving the upper hybrid wave. The latter couples with the pump to drive the sidebands. The growth rate of SRFS monotonically increases by applying a static magnetic field. It also increases with the pump amplitude; however, the dependence is slower than linear.

  2. Internal magnetic field measurement on C-2 field-reversed configuration plasmas.

    Science.gov (United States)

    Gota, H; Thompson, M C; Knapp, K; Van Drie, A D; Deng, B H; Mendoza, R; Guo, H Y; Tuszewski, M

    2012-10-01

    A long-lived field-reversed configuration (FRC) plasma has been produced in the C-2 device by dynamically colliding and merging two oppositely directed, highly supersonic compact toroids (CTs). The reversed-field structure of the translated CTs and final merged-FRC state have been directly verified by probing the internal magnetic field structure using a multi-channel magnetic probe array near the midplane of the C-2 confinement chamber. Each of the two translated CTs exhibits significant toroidal fields (B(t)) with opposite helicity, and a relatively large B(t) remains inside the separatrix after merging.

  3. Magnetic diagnostics: general principles and the problem of reconstruction of plasma current and pressure profiles in toroidal systems

    Energy Technology Data Exchange (ETDEWEB)

    Pustovitov, V.D.

    2000-04-01

    The restrictions of the magnetic diagnostics are discussed. Being related to the integral nature of the measurable quantities, they follow from the fundamental laws of electromagnetism. A series of particular examples demonstrating the strength of these restrictions is given and analyzed. A general rule is emphasized that the information obtained from external magnetic measurements is obviously insufficient for the reliable evaluation of plasma current and pressure profiles in tokamaks or in stellarators. The underlying reason is that outside the plasma the own field of the equilibrium plasma currents is determined by the boundary conditions on the plasma surface only. (author)

  4. Influence of ionization on reflection of solitary waves in a magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jyoti,; Malik, Hitendra K. [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110 016 (India); Kumar, Ravinder [Department of Physics, Janta Vedic College Baraut, Uttar Pradesh 265 001 (India); Dahiya, Raj P. [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110 016 (India)

    2013-09-15

    The reflection of nonlinear solitary waves is studied in a nonuniform, magnetized plasma diffusing from an ionization source along the magnetic field lines. Contribution of the ionization term is included in the continuity equation. The behavior of solitary waves is governed by modified form of Korteweg–de Vries equation (called mKdV equation). In order to investigate the reflection of solitary waves, the mKdV equations for the right and left going waves are derived, and solved by finding new transformations coupled at the point of reflection, for obtaining the expression of reflection coefficient. Contrary to the case of usual inhomogeneous plasma, the present analysis shows that a combination of usual sech{sup 2} structure and tanh structure (called the tail of soliton) arises due to the influence of ionization term. Interestingly, this tailing structure disappears after the reflection of the soliton and hence, the soliton is downshifted prominently.

  5. Influence of ionization on reflection of solitary waves in a magnetized plasma

    Science.gov (United States)

    Jyoti; Kumar, Ravinder; Malik, Hitendra K.; Dahiya, Raj P.

    2013-09-01

    The reflection of nonlinear solitary waves is studied in a nonuniform, magnetized plasma diffusing from an ionization source along the magnetic field lines. Contribution of the ionization term is included in the continuity equation. The behavior of solitary waves is governed by modified form of Korteweg-de Vries equation (called mKdV equation). In order to investigate the reflection of solitary waves, the mKdV equations for the right and left going waves are derived, and solved by finding new transformations coupled at the point of reflection, for obtaining the expression of reflection coefficient. Contrary to the case of usual inhomogeneous plasma, the present analysis shows that a combination of usual sech2 structure and tanh structure (called the tail of soliton) arises due to the influence of ionization term. Interestingly, this tailing structure disappears after the reflection of the soliton and hence, the soliton is downshifted prominently.

  6. Velocity statistics in holographic fluids: magnetized quark-gluon plasma and superfluid flow

    Energy Technology Data Exchange (ETDEWEB)

    Areán, Daniel [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut),Föhringer Ring 6, D-80805, Munich (Germany); Zayas, Leopoldo A. Pando [The Abdus Salam International Centre for Theoretical Physics,Strada Costiera 11, 34014 Trieste (Italy); Michigan Center for Theoretical Physics, Department of Physics, University of Michigan,450 Church Street, Ann Arbor, MI 48109 (United States); Patiño, Leonardo; Villasante, Mario [Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México,A.P. 70-542, México D.F. 04510 (Mexico)

    2016-10-28

    We study the velocity statistics distribution of an external heavy particle in holographic fluids. We argue that when the dual supergravity background has a finite temperature horizon the velocity statistics goes generically as 1/v, compatible with the jet-quenching intuition from the quark-gluon plasma. A careful analysis of the behavior of the classical string whose apparent world sheet horizon deviates from the background horizon reveals that other regimes are possible. We numerically discuss two cases: the magnetized quark-gluon plasma and a model of superfluid flow. We explore a range of parameters in these top-down supergravity solutions including, respectively, the magnetic field and the superfluid velocity. We determine that the velocity statistics goes largely as 1/v, however, as we leave the non-relativistic regime we observe some deviations.

  7. The concept of a plasma centrifuge with a high frequency rotating magnetic field and axial circulation

    Science.gov (United States)

    Borisevich, V. D.; Potanin, E. P.

    2017-07-01

    The possibility of using a rotating magnetic field (RMF) in a plasma centrifuge (PC), with axial circulation to multiply the radial separation effect in an axial direction, is considered. For the first time, a traveling magnetic field (TMF) is proposed to drive an axial circulation flow in a PC. The longitudinal separation effect is calculated for a notional model, using specified operational parameters and the properties of a plasma, comprising an isotopic mixture of 20Ne-22Ne and generated by a high frequency discharge. The optimal intensity of a circulation flow, in which the longitudinal separation effect reaches its maximum value, is studied. The optimal parameters of the RMF and TMF for effective separation, as well as the centrifuge performance, are calculated.

  8. Voyager 2 solar plasma and magnetic field spectral analysis for intermediate data sparsity

    CERN Document Server

    Gallana, Luca; Iovieno, Michele; Fosson, Sophie M; Magli, Enrico; Opher, Merav; Richardson, John D; Tordella, Daniela

    2015-01-01

    The Voyager probes are the furthest, still active, spacecraft ever launched from Earth. During their 38-year trip, they have collected data regarding solar wind properties (such as the plasma velocity and magnetic field intensity). Unfortunately, a complete time evolution of the measured physical quantities is not available. The time series contains many gaps which increase in frequency and duration at larger distances. The aim of this work is to perform a spectral and statistical analysis of the solar wind plasma velocity and magnetic field using Voyager 2 data measured in 1979, when the gaps/signal ratio is of order of unity. This analysis is achieved using four different data reconstruction techniques: averages on linearly interpolated subsets, correlation of linearly interpolated data, compressed sensing spectral estimation, and maximum likelihood data reconstruction. With five frequency decades, the spectra we obtained have the largest frequency range ever computed at 5 astronomical units from the Sun; s...

  9. Dynamics of magnetically trapped particles foundations of the physics of radiation belts and space plasmas

    CERN Document Server

    Roederer, Juan G

    2014-01-01

    This book is a new edition of Roederer’s classic Dynamics of Geomagnetically Trapped Radiation, updated and considerably expanded. The main objective is to describe the dynamic properties of magnetically trapped particles in planetary radiation belts and plasmas and explain the physical processes involved from the theoretical point of view. The approach is to examine in detail the orbital and adiabatic motion of individual particles in typical configurations of magnetic and electric fields in the magnetosphere and, from there, derive basic features of the particles’ collective “macroscopic” behavior in general planetary environments. Emphasis is not on the “what” but on the “why” of particle phenomena in near-earth space, providing a solid and clear understanding of the principal basic physical mechanisms and dynamic processes involved. The book will also serve as an introduction to general space plasma physics, with abundant basic examples to illustrate and explain the physical origin of diff...

  10. Two-dimensional convection and interchange motions in fluids and magnetized plasmas

    DEFF Research Database (Denmark)

    Garcia, O.E.; Bian, N.H.; Naulin, V.

    2006-01-01

    In this contribution some recent investigations of two- dimensional thermal convection relevant to ordinary fluids as well as magnetized plasmas are reviewed. An introductory discussion is given of the physical mechanism for baroclinic vorticity generation and convective motions in stratified...... fluids, emphasizing its relation to interchange motions of non- uniformly magnetized plasmas. This is followed by a review of the theories for the onset of convection and quasi-linear saturation in driven-dissipative systems. Non-linear numerical simulations which result in stationary convective states...... deals with the generation of differential rotation by fluctuating motions through tilting of the convective structures. The role of kinetic energy transfer and shearing due to differential advection is pointed out. Numerical simulations for strongly driven systems reveal turbulent states with a bursty...

  11. Generalized Case ``Van Kampen theory for electromagnetic oscillations in a magnetized plasma

    Science.gov (United States)

    Bairaktaris, F.; Hizanidis, K.; Ram, A. K.

    2017-10-01

    The Case-Van Kampen theory is set up to describe electrostatic oscillations in an unmagnetized plasma. Our generalization to electromagnetic oscillations in magnetized plasma is formulated in the relativistic position-momentum phase space of the particles. The relativistic Vlasov equation includes the ambient, homogeneous, magnetic field, and space-time dependent electromagnetic fields that satisfy Maxwell's equations. The standard linearization technique leads to an equation for the perturbed distribution function in terms of the electromagnetic fields. The eigenvalues and eigenfunctions are obtained from three integrals `` each integral being over two different components of the momentum vector. Results connecting phase velocity, frequency, and wave vector will be presented. Supported in part by the Hellenic National Programme on Controlled Thermonuclear Fusion associated with the EUROfusion Consortium, and by DoE Grant DE-FG02-91ER-54109.

  12. Temporally Resolved Ion Fluorescence Measurements of the Interaction of a Field-Parallel Laser Produced Plasma and an Ambient Magnetized Plasma

    Science.gov (United States)

    Dorst, R. S.; Heuer, P. V.; Bondarenko, A. S.; Shaffer, D. B.; Contantin, G.; Vincena, S.; Tripathi, S.; Gekelman, W.; Weidl, M.; Winske, D.; Niemann, C.

    2016-10-01

    We present measurements of the collisionless coupling between an exploding laser-produced plasma (LPP) and a large, magnetized ambient plasma. The LPP was created by focusing the Raptor laser (400J, 40ns) on a planar plastic target embedded in the ambient Large Plasma Device (LAPD) plasma at the University of Californa, Los Angeles. The resulting ablated material moved parallel to the background magnetic field, interacting with the ambient plasma along the full 17m length of the LAPD. A high temporal and spectral resolution monochrometer measured fluorescence from debris and ambient ions to deter- mine the debris velocity distribution by charge state and study the fast electron precursor to the LPP. Measurements are compared to hybrid simulations of quasi-parallel shocks.

  13. Low magnetic field cooling of lepton plasmas via cyclotron-cavity resonance

    Science.gov (United States)

    Hunter, E. D.; Evetts, N.; Fajans, J.; Hardy, W. N.; Landsberger, H.; Mcpeters, R.; Wurtele, J. S.

    2018-01-01

    Pure electron or pure positron plasmas held in magnetic fields B radiate energy because of the cyclotron motion of the plasma particles; nominally, the plasmas should cool to the often cryogenic temperatures of the trap in which they are confined. However, the cyclotron cooling rate for leptons is (1/4 s)(B/1 T)2, and significant cooling is not normally observed unless B ≳ 1 T . Cooling to the trap temperatures of ˜10 K is particularly difficult to attain. Here, we show that dramatically higher cooling rates (×100) and lower temperatures (÷1000) can be obtained if the plasmas are held in electromagnetic cavities rather than in effectively free space conditions. We find that plasmas with up to 107 particles can be cooled in fields close to 0.15 T, much lower than 1 T commonly thought to be necessary to obtain plasma cooling. Appropriate cavities can be constructed with only minor modifications to the standard Penning-Malmberg trap structures.

  14. Low-frequency surface waves on semi-bounded magnetized quantum plasma

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Engineering Physics, Kermanshah University of Technology, Kermanshah (Iran, Islamic Republic of)

    2016-08-15

    The propagation of low-frequency electrostatic surface waves on the interface between a vacuum and an electron-ion quantum plasma is studied in the direction perpendicular to an external static magnetic field which is parallel to the interface. A new dispersion equation is derived by employing both the quantum magnetohydrodynamic and Poisson equations. It is shown that the dispersion equations for forward and backward-going surface waves are different from each other.

  15. Nonthermal Particle Acceleration in 3D Relativistic Magnetic Reconnection in Pair Plasma

    Science.gov (United States)

    Werner, Gregory R.; Uzdensky, Dmitri A.

    2017-07-01

    As a fundamental process converting magnetic to plasma energy in high-energy astrophysical plasmas, relativistic magnetic reconnection is a leading explanation for the acceleration of particles to the ultrarelativistic energies that are necessary to power nonthermal emission (especially X-rays and gamma-rays) in pulsar magnetospheres and pulsar wind nebulae, coronae and jets of accreting black holes, and gamma-ray bursts. An important objective of plasma astrophysics is therefore the characterization of nonthermal particle acceleration (NTPA) effected by reconnection. Reconnection-powered NTPA has been demonstrated over a wide range of physical conditions using large 2D kinetic simulations. However, its robustness in realistic 3D reconnection—in particular, whether the 3D relativistic drift-kink instability (RDKI) disrupts NTPA—has not been systematically investigated, although pioneering 3D simulations have observed NTPA in isolated cases. Here, we present the first comprehensive study of NTPA in 3D relativistic reconnection in collisionless electron-positron plasmas, characterizing NTPA as the strength of 3D effects is varied systematically via the length in the third dimension and the strength of the guide magnetic field. We find that, while the RDKI prominently perturbs 3D reconnecting current sheets, it does not suppress particle acceleration, even for zero guide field; fully 3D reconnection robustly and efficiently produces nonthermal power-law particle spectra closely resembling those obtained in 2D. This finding provides strong support for reconnection as the key mechanism powering high-energy flares in various astrophysical systems. We also show that strong guide fields significantly inhibit NTPA, slowing reconnection and limiting the energy available for plasma energization, yielding steeper and shorter power-law spectra.

  16. Results from colliding magnetized plasma jet experiments executed at the Trident laser facility

    Science.gov (United States)

    Manuel, M. J.-E.; Rasmus, A. M.; Kurnaz, C. C.; Klein, S. R.; Davis, J. S.; Drake, R. P.; Montgomery, D. S.; Hsu, S. C.; Adams, C. S.; Pollock, B. B.

    2015-11-01

    The interaction of high-velocity plasma flows in a background magnetic field has applications in pulsed-power and fusion schemes, as well as astrophysical environments, such as accretion systems and stellar mass ejections into the magnetosphere. Experiments recently executed at the Trident Laser Facility at the Los Alamos National Laboratory investigated the effects of an expanding aluminum plasma flow into a uniform 4.5-Tesla magnetic field created using a solenoid designed and manufactured at the University of Michigan. Opposing-target experiments demonstrate interesting collisional behavior between the two magnetized flows. Preliminary interferometry and Faraday rotation measurements will be presented and discussed. This work is funded by the U.S Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0001840. Support for this work was provided by NASA through Einstein Postdoctoral Fellowship grant number PF3-140111 awarded by the Chandra X-ray Center, which is operated by the Astrophysical Observatory for NASA under contract NAS8-03060.

  17. Nonlinear phenomena in RF wave propagation in magnetized plasma: A review

    Science.gov (United States)

    Porkolab, Miklos

    2015-12-01

    Nonlinear phenomena in RF wave propagation has been observed from the earliest days in basic laboratory experiments going back to the 1960s [1], followed by observations of parametric instability (PDI) phenomena in large scale RF heating experiments in magnetized fusion plasmas in the 1970s and beyond [2]. Although not discussed here, the importance of PDI phenomena has also been central to understanding anomalous absorption in laser-fusion experiments (ICF) [3]. In this review I shall discuss the fundamentals of nonlinear interactions among waves and particles, and in particular, their role in PDIs. This phenomenon is distinct from quasi-linear phenomena that are often invoked in calculating absorption of RF power in wave heating experiments in the core of magnetically confined plasmas [4]. Indeed, PDIs are most likely to occur in the edge of magnetized fusion plasmas where the electron temperature is modest and hence the oscillating quiver velocity of charged particles can be comparable to their thermal speeds. Specifically, I will review important aspects of PDI theory and give examples from past experiments in the ECH/EBW, lower hybrid (LHCD) and ICRF/IBW frequency regimes. Importantly, PDI is likely to play a fundamental role in determining the so-called "density limit" in lower hybrid experiments that has persisted over the decades and still central to understanding present day experiments [5-7].

  18. Nonlinear phenomena in RF wave propagation in magnetized plasma: A review

    Energy Technology Data Exchange (ETDEWEB)

    Porkolab, Miklos

    2015-12-10

    Nonlinear phenomena in RF wave propagation has been observed from the earliest days in basic laboratory experiments going back to the 1960s [1], followed by observations of parametric instability (PDI) phenomena in large scale RF heating experiments in magnetized fusion plasmas in the 1970s and beyond [2]. Although not discussed here, the importance of PDI phenomena has also been central to understanding anomalous absorption in laser-fusion experiments (ICF) [3]. In this review I shall discuss the fundamentals of nonlinear interactions among waves and particles, and in particular, their role in PDIs. This phenomenon is distinct from quasi-linear phenomena that are often invoked in calculating absorption of RF power in wave heating experiments in the core of magnetically confined plasmas [4]. Indeed, PDIs are most likely to occur in the edge of magnetized fusion plasmas where the electron temperature is modest and hence the oscillating quiver velocity of charged particles can be comparable to their thermal speeds. Specifically, I will review important aspects of PDI theory and give examples from past experiments in the ECH/EBW, lower hybrid (LHCD) and ICRF/IBW frequency regimes. Importantly, PDI is likely to play a fundamental role in determining the so-called “density limit” in lower hybrid experiments that has persisted over the decades and still central to understanding present day experiments [5-7].

  19. Collective acceleration of laser plasma in a nonstationary and nonuniform magnetic field

    Science.gov (United States)

    Isaev, A.; Kozlovskiy, K.; Shikanov, A.; Vovchenko, E.

    2017-12-01

    This paper presents the new experimental results concerning acceleration of deuterium ions extracted from laser plasma in the rapid-growing nonuniform magnetic field in order to initiate the nuclear reactions D(d, n)3He and T(d, n)4He. For obtaining of laser plasma a Nd: YAG laser (λ = 1,06 μm) that generates in Q-switched mode the radiation pulses with the energy W ≤ 0,85 J and duration of τ ≈ 10 ns was used. Rapid-growing magnetic field was created with the discharge of Arkadyev-Marx pulsed-voltage generator to conical coil with the inductance of 0,65 μΗ. At characteristic discharge time of 30 ns, the rate of magnetic field growth achieved 2·107 T/s. Ion velocity was determined with the time-of-flight technique. During the experiment on deuterium plasma an ion flux velocity of ∼3 · 108 cm/s was obtained, which corresponds to the deuteron energy of ∼100 keV. Herewith, for target power density of ∼5·1011 W/cm2 obtaining of up to 1015 of accelerated deuterons and up to 108 of neutrons per a pulse is expected.

  20. Modeling the Southwood Theory of Rotation-Period Perturbations of a Magnetized Plasma

    Science.gov (United States)

    Kivelson, M.; Jia, X.; Southwood, D. J.

    2016-12-01

    Many of Saturn's plasma and field properties vary at approximately Saturn's rotation period. The periodic behavior is imposed by a system of rotating currents whose origin remains uncertain. Southwood has proposed an analytical mathematical model that shows that a uniformly magnetized plasma bounded by a rotating conducting plate at its base naturally develops MHD disturbances that produce the rotating currents and vary at the rotation period of the plate. Such rotationally driven MHD perturbations achieve a steady state and remain azimuthally symmetric, a conclusion consistent with the sinusoidal dependence on Saturn's rotation phase found in the data from Cassini spacecraft measurements. The model is designed to represent flux tubes from either polar cap of Saturn (N or S) that link magnetically to the solar wind. The transverse magnetic field component transmits angular momentum but a compressional component may also develop (as observed). To test this model, we have carried out magnetohydrodynamic simulations of a cylinder filled with a uniform plasma and a constant magnetic field bounded at the base by a conducting plate that is set into rotational motion. Magnetic perturbations develop and propagate through the system. However, results of the simulation are highly sensitive to boundary conditions and, with time, our models depart from the quasi-steady conditions that we desire to represent. We describe aspects of the theory that are reproduced by runs using different boundary conditions and where and why they differ. For all initial conditions and boundary conditions used in the simulation, we find that both transverse and compressional perturbations develop before the simulation becomes unstable or in other ways unrealistic. However, in order to set up a relatively stable oscillating system, we continue to test new boundary conditions that come increasingly close to representing the portion of a magnetosphere linked to the polar cap of a rotating planet.

  1. Single Langmuir probe characteristic in a magnetized plasma at the TEXT tokamak

    Science.gov (United States)

    Jachmich, Stefan

    1995-05-01

    A single Langmuir probe tip was used at TEXT-Upgrade to obtain I-V characteristics in a magnetized plasma. Noisy data were reduced by a boxcar-averaging routine. Unexpected effects, namely nonsaturation of ion current, hysterises in the characteristics and I(V)-data were observed, which are in disagreement to the common single probe model. A double probe model allows parameterization of the I(V) curves and to determine the plasma properties in the scrape-off layer. It is shown in this model that a Langmuir probe does perturb the local space potential in the plasma. Comparisons were made with the triple probe technique of measuring temperatures. The nonsaturation of ion current leads to an error in the triple probe technique of order 20%.

  2. Low frequency solitons and double layers in a magnetized plasma with two temperature electrons

    Energy Technology Data Exchange (ETDEWEB)

    Rufai, O. R. [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Bharuthram, R. [Office of the Deputy Vice Chancellor (Academic), University of the Western Cape, Bellville (South Africa); Singh, S. V. [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai-410218 (India); School of Chemistry and Physics, University of Kwa-Zulu Natal, Durban (South Africa); Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai-410218 (India)

    2012-12-15

    Finite amplitude non-linear ion-acoustic solitary waves and double layers are studied in a magnetized plasma with cold ions fluid and two distinct groups of Boltzmann electrons, using the Sagdeev pseudo-potential technique. The conditions under which the solitary waves and double layers can exist are found both analytically and numerically. We have shown the existence of negative potential solitary waves and double layers for subsonic Mach numbers, whereas in the unmagnetized plasma they can only in the supersonic Mach number regime. For the plasma parameters in the auroral region, the electric field amplitude of the solitary structures comes out to be 49 mV/m which is in agreement of the Viking observations in this region.

  3. Rotating Magnetic Field FRC Formation Studies using the Multi-Fluid Plasma Model

    Science.gov (United States)

    Sousa, Eder

    2016-10-01

    The multi-fluid plasma model equations are derived by taking velocity moments of the Boltzmann equation for each of the components in a plasma, and each species mass density, momentum density and total energy are evolved in time. This model is used to study field-reversed configuration (FRC) formation dynamics using a Rotating Magnetic Field (RMF) as an electron current drive. Particular interest is placed on the coupling of the RMF to the plasma and collisional effects between the electron, ion and neutral fluids, and some consideration to ionization effects. The simulations are designed such that they can be compared to experimental results using collisional-radiative (CR) models developed at the Air Force Research Laboratory. Distribution A: Approved for public release; distribution unlimited AFTC/PA clearance No. 15399.

  4. Transcranial magnetic stimulation and BDNF plasma levels in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Angelucci, Francesco; Oliviero, Antonio; Pilato, Fabio; Saturno, Eleonora; Dileone, Michele; Versace, Viviana; Musumeci, Gabriella; Batocchi, Anna P; Tonali, Pietro A; Di Lazzaro, Vincenzo

    2004-03-22

    Low- and high-frequency repetitive transcranial magnetic stimulation (rTMS) of the motor cortex results in lasting changes of excitatory neurotransmission. We investigated the effects of suprathreshold 1 Hz rTMS on brain derived neurotrophic factor (BDNF) plasma levels in 10 healthy subjects and effects of either 1 Hz or 20 Hz rTMS in four amyotrophic lateral sclerosis (ALS) patients. BDNF levels were progressively decreased by 1 Hz rTMS in healthy subjects; there was no effect of 1 Hz rTMS on BDNF plasma levels in ALS patients, an effect probably due to the loss of motor cortex pyramidal cells. High frequency rTMS determined a transitory decrease in BDNF plasma levels. Cumulatively these findings suggest that rTMS might influence the BDNF production by interfering with neuronal activity.

  5. Solitary wave evolution in a magnetized inhomogeneous plasma under the effect of ionization

    Science.gov (United States)

    Jyoti; Malik, Hitendra K.

    2011-10-01

    A modified form of Korteweg-deVries (KdV) equation appropriate to nonlinear ion acoustic solitary waves in an inhomogeneous plasma is derived in the presence of an external magnetic field and constant ionization in the plasma. This equation differs from usual version of the KdV equation because of the inclusion of two terms arising due to ionization and density gradient present in the plasma. In this plasma, only the compressive solitary waves are found to propagate corresponding to the fast and slow modes. The amplitude of the solitary wave increases with an enhancement in the ionization for the fast mode as well as for the slow mode. The effect of magnetic field is to enhance the width of the solitary structure. The amplitude is found to increase (decrease) with an enhancement in charge number of the ions for the fast (slow) mode. The tailing structure becomes more (less) prominent with the rise in ion drift velocity for the case of fast (slow) mode.

  6. Modified dust ion-acoustic surface waves in a semi-bounded magnetized plasma containing the rotating dust grains

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung-Jae [Department of Physics and Research Institute for Natural Sciences, Hanyang University, Seoul 04763 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States); Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588 (Korea, Republic of)

    2016-05-15

    The dispersion relation for modified dust ion-acoustic surface waves in the magnetized dusty plasma containing the rotating dust grains is derived, and the effects of magnetic field configuration on the resonant growth rate are investigated. We present the results that the resonant growth rates of the wave would increase with the ratio of ion plasma frequency to cyclotron frequency as well as with the increase of wave number for the case of perpendicular magnetic field configuration when the ion plasma frequency is greater than the dust rotation frequency. For the parallel magnetic field configuration, we find that the instability occurs only for some limited ranges of the wave number and the ratio of ion plasma frequency to cyclotron frequency. The resonant growth rate is found to decrease with the increase of the wave number. The influence of dust rotational frequency on the instability is also discussed.

  7. Quasi-discrete particle motion in an externally imposed, ordered structure in a dusty plasma at high magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Edward, E-mail: etjr@auburn.edu; Konopka, Uwe; Lynch, Brian; Adams, Stephen; LeBlanc, Spencer [Physics Department, Auburn University, Auburn, Alabama 36849 (United States); Merlino, Robert L. [Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 (United States); Rosenberg, Marlene [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

    2015-11-15

    Dusty plasmas have been studied in argon, radio frequency (rf) glow discharge plasmas at magnetic fields up to 2.5 T where the electrons and ions are strongly magnetized. Plasmas are generated between two parallel plate electrodes where the lower, powered electrode is solid and the upper electrode supports a dual mesh consisting of #24 brass and #30 aluminum wire cloth. In this experiment, we study the formation of imposed ordered structures and particle dynamics as a function of magnetic field. Through observations of trapped particles and the quasi-discrete (i.e., “hopping”) motion of particles between the trapping locations, it is possible to make a preliminary estimate of the potential structure that confines the particles to a grid structure in the plasma. This information is used to gain insight into the formation of the imposed grid pattern of the dust particles in the plasma.

  8. Modeling weakly-ionized plasmas in magnetic field: A new computationally-efficient approach

    Science.gov (United States)

    Parent, Bernard; Macheret, Sergey O.; Shneider, Mikhail N.

    2015-11-01

    Despite its success at simulating accurately both non-neutral and quasi-neutral weakly-ionized plasmas, the drift-diffusion model has been observed to be a particularly stiff set of equations. Recently, it was demonstrated that the stiffness of the system could be relieved by rewriting the equations such that the potential is obtained from Ohm's law rather than Gauss's law while adding some source terms to the ion transport equation to ensure that Gauss's law is satisfied in non-neutral regions. Although the latter was applicable to multicomponent and multidimensional plasmas, it could not be used for plasmas in which the magnetic field was significant. This paper hence proposes a new computationally-efficient set of electron and ion transport equations that can be used not only for a plasma with multiple types of positive and negative ions, but also for a plasma in magnetic field. Because the proposed set of equations is obtained from the same physical model as the conventional drift-diffusion equations without introducing new assumptions or simplifications, it results in the same exact solution when the grid is refined sufficiently while being more computationally efficient: not only is the proposed approach considerably less stiff and hence requires fewer iterations to reach convergence but it yields a converged solution that exhibits a significantly higher resolution. The combined faster convergence and higher resolution is shown to result in a hundredfold increase in computational efficiency for some typical steady and unsteady plasma problems including non-neutral cathode and anode sheaths as well as quasi-neutral regions.

  9. Energy loss of ions by electric-field fluctuations in a magnetized plasma.

    Science.gov (United States)

    Nersisyan, Hrachya B; Deutsch, Claude

    2011-06-01

    The results of a theoretical investigation of the energy loss of charged particles in a magnetized classical plasma due to the electric-field fluctuations are reported. The energy loss for a test particle is calculated through the linear-response theory. At vanishing magnetic field, the electric-field fluctuations lead to an energy gain of the charged particle for all velocities. It has been shown that in the presence of strong magnetic field, this effect occurs only at low velocities. In the case of high velocities, the test particle systematically loses its energy due to the interaction with a stochastic electric field. The net effect of the fluctuations is the systematic reduction of the total energy loss (i.e., the sum of the polarization and stochastic energy losses) at vanishing magnetic field and reduction or enhancement at strong field, depending on the velocity of the particle. It is found that the energy loss of the slow heavy ion contains an anomalous term that depends logarithmically on the projectile mass. The physical origin of this anomalous term is the coupling between the cyclotron motion of the plasma electrons and the long-wavelength, low-frequency fluctuations produced by the projectile ion. This effect may strongly enhance the stochastic energy gain of the particle.

  10. Measurements and Phenomenological Modeling of Magnetic FluxBuildup in Spheromak Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Talamas, C A; Hooper, E B; Jayakumar, R; McLean, H S; Wood, R D; Moller, J M

    2007-12-14

    Internal magnetic field measurements and high-speed imaging at the Sustained Spheromak Physics Experiment (SSPX) [E. B. Hooper, L. D. Pearlstein, R. H. Bulmer, Nucl. Fusion 39, 863 (1999)] are used to study spheromak formation and field buildup. The measurements are analyzed in the context of a phenomenological model of magnetic helicity based on the topological constraint of minimum helicity in the open flux before reconnecting and linking closed flux. Two stages are analyzed: (1) the initial spheromak formation, i. e. when all flux surfaces are initially open and reconnect to form open and closed flux surfaces, and (2) the stepwise increase of closed flux when operating the gun on a new mode that can apply a train of high-current pulses to the plasma. In the first stage, large kinks in the open flux surfaces are observed in the high-speed images taken shortly after plasma breakdown, and coincide with large magnetic asymmetries recorded in a fixed insertable magnetic probe that spans the flux conserver radius. Closed flux (in the toroidal average sense) appears shortly after this. This stage is also investigated using resistive magnetohydrodynamic simulations. In the second stage, a time lag in response between open and closed flux surfaces after each current pulse is interpreted as the time for the open flux to build helicity, before transferring it through reconnection to the closed flux. Large asymmetries are seen during these events, which then relax to a slowly decaying spheromak before the next pulse.

  11. Characterization of cylindrically imploded magnetized plasma by spectroscopy and proton probing

    Science.gov (United States)

    Dozieres, M.; Forestier-Colleoni, P.; Wei, M. S.; Gourdain, P.-A.; Davies, J. R.; Fujioka, S.; Peebles, J.; Campbell, M.; Santos, J. J.; Batani, D.; McGuffey, C.; Beg, F. N.

    2017-10-01

    Understanding the role of magnetic field in relativistic electron beam transport and energy deposition is important for several applications including fast ignition inertial confinement fusion. We report the development of a cylindrically compressed target platform with externally applied magnetic fields on OMEGA. As a first step, we performed an experiment to characterize the imploded plasma and compressed field condition. The implosion of the target was performed using 36 UV beams (400 J per beam, 1.5 ns square pulse), and the magnetic field was measured by proton deflection using mono-energetic protons produced from D3He capsule implosion. The target was a CH foam cylinder doped with 1% chlorine in order to detect the time-resolved 1s-2p Cl absorption structures, using a gold foil as a broad band backlighter source. A Cu foil at the beginning of the foam cylinder and a Zn foil at the end, allowed us to measure the K α and the 1s-2p transitions of He-like and Li-like ions for both elements. The emission and absorption spectroscopic data are compared to atomic physics codes to determine the plasma temperature and density under the influence of the magnetic field. FOA-0001568.

  12. Spontaneous onset of magnetic reconnection in toroidal plasma caused by breaking of 2D symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Egedal, Jan; Katz, Noam; Bonde, Jeff; Fox, Will; Le, Ari; Porkolab, Miklos; Vrublevskis, Arturs [Department of Physics/Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2011-11-15

    Magnetic reconnection is studied in the collisionless limit at the Versatile Toroidal Facility (VTF) at MIT. Two distinct magnetic configurations are applied in the experiments; an open magnetic cusp and a closed cusp. In the open cusp configurations, the field lines intersect the the vacuum vessel walls and here axisymmetric oscillatory reconnection is observed. Meanwhile, in the closed cusp configuration, where the field lines are confined inside the experiment, the coupling between global modes and a current sheet leads to powerful bursts of 3D spontaneous reconnection. These spontaneous events start at one toroidal location, and then propagate around the toroidal direction at the Alfven speed (calculated with the strength of the dominant guide field). The three dimensional measurements include the detailed time evolution of the plasma density, current density, the magnetic flux function, the electrostatic potential, and the reconnection rate. The vastly different plasma behavior in the two configurations can be described using a simple theoretical framework, linking together the interdependencies of the reconnection rate, the in-plane electrostatic potential, and the parallel electron currents. We find that it is the breaking of toroidal symmetry by the global mode that allows for a localized disruption of the x-line current and hereby facilitates the onset of spontaneous reconnection.

  13. Magnetic field production via the Weibel instability in interpenetrating plasma flows

    Science.gov (United States)

    Huntington, C. M.; Manuel, M. J.-E.; Ross, J. S.; Wilks, S. C.; Fiuza, F.; Rinderknecht, H. G.; Park, H.-S.; Gregori, G.; Higginson, D. P.; Park, J.; Pollock, B. B.; Remington, B. A.; Ryutov, D. D.; Ruyer, C.; Sakawa, Y.; Sio, H.; Spitkovsky, A.; Swadling, G. F.; Takabe, H.; Zylstra, A. B.

    2017-04-01

    Many astrophysical systems are effectively "collisionless," that is, the mean free path for collisions between particles is much longer than the size of the system. The absence of particle collisions does not preclude shock formation, however, as shocks can be the result of plasma instabilities that generate and amplify electromagnetic fields. The magnetic fields required for shock formation may either be initially present, for example, in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the Weibel instability is a candidate mechanism for the generation of sufficiently strong magnetic fields to produce shocks. In experiments on the OMEGA Laser, we have demonstrated a quasi-collisionless system that is optimized for the study of the non-linear phase of Weibel instability growth. Using a proton probe to directly image electromagnetic fields, we measure Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows. The collisionality of the system is determined from coherent Thomson scattering measurements, and the data are compared to similar measurements of a fully collisionless system. The strong, persistent Weibel growth observed here serves as a diagnostic for exploring large-scale magnetic field amplification and the microphysics present in the collisional-collisionless transition.

  14. Parallel acceleration due to the radial electric field in a magnetized plasma with low-frequency turbulence

    OpenAIRE

    Wang, Shaojie

    2014-01-01

    A new physical mechanism of the parallel acceleration of a turbulent magnetized plasma is discovered by using a Fokker-Planck phase space stochastic transport equation. It is found that the random walk of a charged particle is correlated with the random change of the parallel velocity due to the radial electric field and the magnetic moment conservation. This correlation leads to a parallel acceleration of the plasma with a finite parallel fluid flow.

  15. Single-step synthesis of carbon encapsulated magnetic nanoparticles in arc plasma and potential biomedical applications.

    Science.gov (United States)

    Fang, Xiuqi; Cheng, Xiaoqian; Zhang, Yuerou; Zhang, Lijie Grace; Keidar, Michael

    2018-01-01

    A novel highly controllable process of Carbon Encapsulated Magnetic Nanoparticles (CEMNs) synthesis in arc discharge plasma has been developed. In this work, both the size distribution and the purity of the CEMNs have been made more controllable by adding an external magnetic field. It is shown that with the increase of the external magnetic field, the CEMNs get a better separation from the carbon impurities and the size distribution become narrower. This conclusion is valid for Fe, Ni and Fe+Ni CEMNs synthesis. In order to assess biomedical potential of these CEMNs, the cytotoxicity has also been measured for the human breast adenocarcinoma cell line MDA-MB-231. It was concluded that the CEMNs with the concentration in cell of about 0.0001-0.01ug/ml are not toxic. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Plasma Equilibrium in a Magnetic Field with Stochastic Field-Line Trajectories

    Science.gov (United States)

    Krommes, J. A.; Reiman, A. H.

    2008-11-01

    The nature of plasma equilibrium in a magnetic field with stochastic field lines is examined, expanding upon the ideas first described by Reiman et al. The magnetic partial differential equation (PDE) that determines the equilibrium Pfirsch-Schlüter currents is treated as a passive stochastic PDE for μj/B. Renormalization leads to a stochastic Langevin equation for μ in which the resonances at the rational surfaces are broadened by the stochastic diffusion of the field lines; even weak radial diffusion can significantly affect the equilibrium, which need not be flattened in the stochastic region. Particular attention is paid to satisfying the periodicity constraints in toroidal configurations with sheared magnetic fields. A numerical scheme that couples the renormalized Langevin equation to Ampere's law is described. A. Reiman et al, Nucl. Fusion 47, 572--8 (2007). J. A. Krommes, Phys. Reports 360, 1--351.

  17. Confinement and dynamics of laser-produced plasma expanding across a transverse magnetic field.

    Science.gov (United States)

    Harilal, S S; Tillack, M S; O'Shay, B; Bindhu, C V; Najmabadi, F

    2004-02-01

    The dynamics and confinement of laser-created plumes expanding across a transverse magnetic field have been investigated. 1.06 microm, 8 ns pulses from a neodymium-doped yttrium aluminum garnet laser were used to create an aluminum plasma which was allowed to expand across a 0.64 T magnetic field. Fast photography, emission spectroscopy, and time of flight spectroscopy were used as diagnostic tools. Changes in plume structure and dynamics, enhanced emission and ionization, and velocity enhancement were observed in the presence of the magnetic field. Photographic studies showed that the plume is not fully stopped and diffuses across the field. The temperature of the plume was found to increase due to Joule heating and adiabatic compression. The time of flight studies showed that all of the species are slowed down significantly. A multiple peak temporal distribution was observed for neutral species.

  18. Magnetic Reconnection, a Key Self-Organization Process in Laboratory and Astrophysical Plasmas : Recent Research Progress(Nonequilibrium Dynamics in Astrophysics and Materials Science)

    OpenAIRE

    MASAAKI, YAMADA; Center of Magnetic Self-Organization, Princeton Plasmas Physics Laboratory, Princeton University

    2012-01-01

    Magnetic reconnection is a phenomenon of nature in which magnetic field lines change their topology and convert magnetic energy to plasma particles by acceleration and heating. The process can stretch out over time or occur quite suddenly. It is one of the most fundamental processes at work in laboratory and astrophysical plasmas. Magnetic reconnection occurs everywhere: In solar flares; coronal mass ejections; the earth's magnetosphere; in the star forming galaxies; and in plasma fusion devi...

  19. Electromagnetic fluctuation spectra of collective oscillations in magnetized Maxwellian equal mass plasmas for low-frequency waves

    Energy Technology Data Exchange (ETDEWEB)

    Vafin, S.; Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- & Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); Scholl of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of)

    2016-05-15

    Recently, the general electromagnetic fluctuation theory for magnetized plasmas has been used to study the steady-state fluctuation spectra and the total intensity of low-frequency collective weakly damped modes for parallel wave vectors in Maxwellian plasmas. Now, we address the same question with respect to an arbitrary direction of the wave-vector. Here, we analyze this problem for equal mass plasmas. These plasmas are a very good tool to study various plasma phenomena, as they considerably facilitate the theoretical consideration and at the same time provide with their clear physical picture. Finally, we compare our results in the limiting case of parallel wave vectors with the previous study.

  20. Seeded and unseeded helical modes in magnetized, non-imploding cylindrical liner-plasmas

    Science.gov (United States)

    Yager-Elorriaga, D. A.; Zhang, P.; Steiner, A. M.; Jordan, N. M.; Lau, Y. Y.; Gilgenbach, R. M.

    2016-10-01

    In this research, we generated helical instability modes using unseeded and kink-seeded, non-imploding liner-plasmas at the 1 MA Linear Transformer Driver facility at the University of Michigan in order to determine the effects of externally applied, axial magnetic fields. In order to minimize the coupling of sausage and helical modes to the magneto Rayleigh-Taylor instability, the 400 nm-thick aluminum liners were placed directly around straight-cylindrical (unseeded) or threaded-cylindrical (kink-seeded) support structures to prevent implosion. The evolution of the instabilities was imaged using a combination of laser shadowgraphy and visible self-emission, collected by a 12-frame fast intensified CCD camera. With no axial magnetic field, the unseeded liners developed an azimuthally correlated m = 0 sausage instability (m is the azimuthal mode number). Applying a small external axial magnetic field of 1.1 T (compared to peak azimuthal field of 30 T) generated a smaller amplitude, helically oriented instability structure that is interpreted as an m = +2 helical mode. The kink-seeded liners showed highly developed helical structures growing at the seeded wavelength of λ = 1.27 mm. It was found that the direction of the axial magnetic field played an important role in determining the overall stabilization effects; modes with helices spiraling in the opposite direction of the global magnetic field showed the strongest stabilization. Finally, the Weis-Zhang analytic theory [Weis et al., Phys. Plasmas 22, 032706 (2015)] is used to calculate sausage and helical growth rates for experimental parameters in order to study the effects of axial magnetic fields.

  1. Interaction of a magnetic island chain in a tokamak plasma with a resonant magnetic perturbation of rapidly oscillating phase

    Science.gov (United States)

    Fitzpatrick, Richard

    2017-12-01

    An investigation is made into the interaction of a magnetic island chain, embedded in a tokamak plasma, with an externally generated magnetic perturbation of the same helicity whose helical phase is rapidly oscillating. The analysis is similar in form to the classic analysis used by Kapitza [Sov. Phys. JETP 21, 588 (1951)] to examine the angular motion of a rigid pendulum whose pivot point undergoes rapid vertical oscillations. The phase oscillations are found to modify the existing terms, and also to give rise to new terms, in the equations governing the secular evolution of the island chain's radial width and helical phase. An examination of the properties of the new secular evolution equation reveals that it is possible to phase-lock an island chain to an external magnetic perturbation with an oscillating helical phase in a stabilizing phase relation provided that the amplitude, ɛ, of the phase oscillations (in radians) is such that |J0(ɛ )|≪1 , and the mean angular frequency of the perturbation closely matches the natural angular frequency of the island chain.

  2. Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device

    Energy Technology Data Exchange (ETDEWEB)

    Peng, S.Y.

    1991-07-01

    Ion Cyclotron Range of Frequency (ICRF) wave propagation in an inhomogeneous axial magnetic field in a cylindrical plasma-vacuum system has historically been inadequately modelled. Previous works either sacrifice the cylindrical geometry in favor of a simpler slab geometry, concentrate on the resonance region, use a single mode to represent the entire field structure, or examine only radial propagation. This thesis performs both analytical and computational studies to model the ICRF wave-plasma coupling and propagation problem. Experimental analysis is also conducted to compare experimental results with theoretical predictions. Both theoretical as well as experimental analysis are undertaken as part of the thesis. The theoretical studies simulate the propagation of ICRF waves in an axially inhomogeneous magnetic field and in cylindrical geometry. Two theoretical analysis are undertaken - an analytical study and a computational study. The analytical study treats the inhomogeneous magnetic field by transforming the (r,z) coordinate into another coordinate system ({rho},{xi}) that allows the solution of the fields with much simpler boundaries. The plasma fields are then Fourier transformed into two coupled convolution-integral equations which are then differenced and solved for both the perpendicular mode number {alpha} as well as the complete EM fields. The computational study involves a multiple eigenmode computational analysis of the fields that exist within the plasma-vacuum system. The inhomogeneous axial field is treated by dividing the geometry into a series of transverse axial slices and using a constant dielectric tensor in each individual slice. The slices are then connected by longitudinal boundary conditions.

  3. Reduction of poloidal magnetic flux consumption during plasma current ramp-up in DEMO relevant plasma regimes

    Science.gov (United States)

    Wakatsuki, T.; Suzuki, T.; Hayashi, N.; Shiraishi, J.; Sakamoto, Y.; Ide, S.; Kubo, H.; Kamada, Y.

    2017-01-01

    The method for reducing a poloidal magnetic flux consumption of external coils is investigated to reduce the size of the central solenoid (CS) in the DEMO reactor. The reduction of the poloidal magnetic flux consumption during a plasma current ramp-up phase by electron cyclotron (EC) heating is investigated using an integrated modeling code suite, TOPICS. A strongly reversed shear q profile tends to be produced if intense off-axis EC heating is applied to obtain a large reduction of the flux consumption. In order to overcome this tendency, we find a method to obtain the optimum temperature profile which minimizes the poloidal flux consumption for a wide range of the q profile. We try to reproduce the optimum temperature profile for a weakly reversed shear q profile using six EC rays of 20 MW. As a result, the resistive flux consumption during the current ramp-up can be reduced by 63% from the estimation using the Ejima constant of 0.45 and the total flux consumption can be reduced by 20% from the conventional estimation. In addition, we find that the resistive flux consumption is closely related to the volume averaged electron temperature and not to the profile shape. Using this relation, the required heating power is estimated to be 31 MW based on a well established global confinement scaling, ITER L-89P. As a result, it is clarified that the poloidal magnetic flux consumption can be reduced by 20% using 20-31 MW of EC heating for a weakly reversed shear q profile. This reduction of the flux consumption accounts for 10% reduction of the CS radius.

  4. Anisotropic and asymmetric fast ion distribution generated by magnetic reconnection in MST plasmas

    Science.gov (United States)

    Kim, Jungha; Anderson, Jay; Bonofiglo, Phillip; Harvey, Robert; Sarff, John

    2017-10-01

    Magnetic reconnection is important in particle transport and energization in both astrophysical and laboratory plasmas. Global reconnection events in MST spontaneously generate an anisotropic ion distribution with a high energy tail extending up to 30x thermal energy, likely through a multi-step process that involves multiple physical scale lengths. First, thermal ions are heated by a mechanism that operates preferentially perpendicular to the magnetic field. Second, the higher energy portion of the thermal ion distribution moves into orbits that drift off the stochastic background magnetic field. In the reversed field pinch (RFP) configuration, these drift velocities contribute to stable fast ion orbits that are low in diffusivity and favorable to confinement. These fast ions, separated from the background magnetic field, are unaffected by fluctuation-based, dynamo-like emfs that reduce the total electric field to 0.5 V/m. Finally, a parallel electric field ( 80 V/m), induced by the fast change in the equilibrium during magnetic relaxation, accelerates these fast ions, resulting in an ion distribution that favors high energy, parallel-streaming ions. Work is underway to model the time evolution of the fast ion distribution using CQL3D (Fokker-Planck equation solver) and RIO (full orbit tracer). Work supported by US DOE.

  5. Effect of external electric and magnetic field on propagation of atmospheric pressure plasma jet

    Science.gov (United States)

    Zhu, Ping; Meng, Zhaozhong; Hu, Haixin; Ouyang, Jiting

    2017-10-01

    The behaviors of atmospheric pressure plasma jet produced by a coplanar dielectric barrier discharge (CDBD) in helium in external electrostatic and magnetic field are investigated experimentally. Time-resolved ICCD images of jet in electric field, magnetic field, and floating metal ring are recorded, respectively. The results show that the jet dynamics is affected significantly by a metal ring, an electric, and/or a magnetic field. In a transverse electric field, the jet shows behavior of deflection, broadening, and shortening according to the structure of electric field. In a transverse magnetic field, the jet deflects to up or down depending on the magnetic direction. The jet can be slowed down or obstructed by a floating metal ring on the jet path, but will still pass through the tube at higher applied voltages of DBD, without significant change in jet length or shape out of the tube compared with that without metal ring. A positive DC voltage on the metal ring helps to improve the jet length, but a negative voltage will reduce the length or completely stop the jet. The electric field to sustain the jet in helium is estimated to be about 24 ± 15 kV/cm from this experiment.

  6. A rotation/magnetism analogy for the quark–gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    McInnes, Brett, E-mail: matmcinn@nus.edu.sg

    2016-10-15

    In peripheral heavy ion collisions, the Quark–Gluon Plasma that may be formed often has a large angular momentum per unit energy. This angular momentum may take the form of (local) rotation. In many physical systems, rotation can have effects analogous to those produced by a magnetic field; thus, there is a risk that the effects of local rotation in the QGP might be mistaken for those of the large genuine magnetic fields which are also known to arise in these systems. Here we use the gauge-gravity duality to investigate this, and we find indeed that, with realistic parameter values, local rotation has effects on the QGP (at high values of the baryonic chemical potential) which are not only of the same kind as those produced by magnetic fields, but which can in fact be substantially larger. Furthermore, the combined effect of rotation and magnetism is to change the shape of the main quark matter phase transition line in an interesting way, reducing the magnitude of its curvature; again, local rotation contributes to this phenomenon at least as strongly as magnetism.

  7. Heat Transfer Affected by Transverse Magnetic Field using 3D Modeling of Arc Plasma

    Science.gov (United States)

    Maeda, Yoshifumi; Tanaka, Tatsuro; Yamamoto, Shinji; Iwao, Toru

    2016-10-01

    Gas shielded metal arc welding is used to join the various metal because this is the high quality joining technology. Thus, this welding is used for a welding of large buildings such as bridges and LNG tanks. However, the welding defect caused by the heat transfer decrement may occur with increasing the wind velocity. This is because that the convection loss increases because the arc deflects to leeward side with increasing the wind velocity. In order to prevent from the arc deflection, it is used that the transverse magnetic field is applied to the arc. However, the arc deflection occurs with increasing the transverse magnetic field excessively. The energy balance of the arc is changed with increasing the convection loss caused by the arc deflection, and the heat transfer to the anode decreases. Therefore, the analysis including the arc and anode is necessary to elucidate the heat transfer to the anode. In this paper, the heat transfer affected by the transverse magnetic field using 3D modeling of the arc plasma is elucidated. The heat transfer to the anode is calculated by using the EMTF(electromagnetic thermal fluid) simulation with increasing the transverse magnetic field. As a result, the heat transfer decreased with increasing the transverse magnetic field.

  8. Permanent-magnet helicon sources and arrays: a new type of RF plasma

    Science.gov (United States)

    Chen, Francis F.

    2008-11-01

    Among radiofrequency (rf) plasma sources used for materials processing in industry, helicon sources are well known for their high density but seldom used because they require a large dc magnetic field, making the source larger, heavier, more complex, and costlier than other available sources. Placing the plasma inside an annular permanent magnet (PM) does not work because the field lines carry the plasma into the wall before it can be ejected towards a substrate. However, a ring magnet has a stagnation point below which the field is weaker but almost straight. Use of a ``low-field peak'' partly compensates for the weak field by spacing a back plate so that the reflected wave constructively interferes. Strong PM helicon discharges were produced in a proof-of principle experiment. The discharge tube was optimized using the HELIC code, resulting in 2'' diam by 2'' high, with a three-turn m = 0 antenna at the bottom end. The NeFeB magnet is 3'' ID x 5'' OD by 1'' high. To cover large substrates, an 8-tube array was constructed with 7'' between tubes. Array sources have three problems: 1) the power must be distributed equally, 2) all tubes cannot be the same distance from the matching circuit, and 3) the transmission lines have to handle the voltage at startup and the current in CW operation. These have been solved in the Medusa 2 experiment which is in a ``sweet spot'' in which the small antennas have the right inductance for the rf system. With 3kW total @ 13.56 MHz, at 7'' below the sources, the density is ˜5 x 10^11 cm-3 at 1.3 eV in 15 mTorr of argon, uniform to 3% over the area covered by the tubes. Possible applications are to optical coating, roll-to-roll web processing, flexible and OLED displays, solar cells, and ``smart windows'' with organic solar cells. F.F. Chen and H. Torreblanca, Plasma Phys. Control. Fusion 49, A81 (2007). D. Arnush, Phys. Plasmas 7, 3042 (2000).

  9. Relativistic magnetic reconnection driven by a moderately intense laser interacting with a micro-plasma-slab

    Science.gov (United States)

    Yi, Longqing; Shen, Baifei; Pukhov, Alexander; Fülöp, Tünde

    2017-10-01

    Magnetic reconnection (MR) in the relativistic regime is generally thought to be responsible for powering rapid bursts of non-thermal radiation in astrophysical events. It is therefore of significant importance to study how the field energy is transferred to the plasma to power the observed emission. However, due to the difficulty in making direct measurements in astrophysical systems or achieving relativistic MR in laboratory environments, the particle acceleration is usually studied using fully kinetic PIC simulations. Here we present a numerical study of a readily available (TW-mJ-class) laser interacting with a micro-scale plasma slab. The simulations show when the electron beams excited on both sides of the slab approach the end of the plasma structure, ultrafast relativistic MR occurs. As the field topology changes, the explosive release of magnetic energy results in emission of relativistic electron jets with cut-off energy 12 MeV. The proposed novel scenario can be straightforwardly implemented in experiments, and might significantly improve the understanding of fundamental questions such as field dissipation and particle acceleration in relativistic MR. This work is supported by the Knut and Alice Wallenberg Foundation and the European Research Council (ERC-2014-CoG Grant 64712).

  10. Particle-in-Cell Modeling of Magnetized Argon Plasma Flow Through Small Mechanical Apertures

    Energy Technology Data Exchange (ETDEWEB)

    Adam B. Sefkow and Samuel A. Cohen

    2009-04-09

    Motivated by observations of supersonic argon-ion flow generated by linear helicon-heated plasma devices, a three-dimensional particle-in-cell (PIC) code is used to study whether stationary electrostatic layers form near mechanical apertures intersecting the flow of magnetized plasma. By self-consistently evaluating the temporal evolution of the plasma in the vicinity of the aperture, the PIC simulations characterize the roles of the imposed aperture and applied magnetic field on ion acceleration. The PIC model includes ionization of a background neutral-argon population by thermal and superthermal electrons, the latter found upstream of the aperture. Near the aperture, a transition from a collisional to a collisionless regime occurs. Perturbations of density and potential, with mm wavelengths and consistent with ion acoustic waves, propagate axially. An ion acceleration region of length ~ 200-300 λD,e forms at the location of the aperture and is found to be an electrostatic double layer, with axially-separated regions of net positive and negative charge. Reducing the aperture diameter or increasing its length increases the double layer strength.

  11. Fast magnetic twister and plasma perturbations in a three-dimensional coronal arcade

    Energy Technology Data Exchange (ETDEWEB)

    Murawski, K. [Group of Astrophysics, UMCS, ul. Radziszewskiego 10, 20-031 Lublin (Poland); Srivastava, A. K. [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi-221005 (India); Musielak, Z. E., E-mail: kmur@kft.umcs.lublin.pl, E-mail: asrivastava.app@iitbhu.ac.in, E-mail: zmusielak@uta.edu, E-mail: musielak@kis.uni-freiburg.de [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2014-06-10

    We present results of three-dimensional (3D) numerical simulations of a fast magnetic twister excited above a foot-point of the potential solar coronal arcade that is embedded in the solar atmosphere with the initial VAL-IIIC temperature profile, which is smoothly extended into the solar corona. With the use of the FLASH code, we solve 3D ideal magnetohydrodynamic equations by specifying a twist in the azimuthal component of magnetic field in the solar chromosphere. The imposed perturbation generates torsional Alfvén waves as well as plasma swirls that reach the other foot-point of the arcade and partially reflect back from the transition region. The two vortex channels are evident in the generated twisted flux-tube with a fragmentation near its apex which results from the initial twist as well as from the morphology of the tube. The numerical results are compared to observational data of plasma motions in a solar prominence. The comparison shows that the numerical results and the data qualitatively agree even though the observed plasma motions occur over comparatively large spatio-temporal scales in the prominence.

  12. Electron beam injection experiments - The beam-plasma discharge at low pressures and magnetic field strengths

    Science.gov (United States)

    Bernstein, W.; Leinbach, H.; Kellogg, P.; Monson, S.; Hallinan, T.; Garriott, O. K.; Konradi, A.; Mccoy, J.; Daly, P.; Baker, B.

    1978-01-01

    The paper describes electron beam injection experiments which clarify observational results obtained in rocket flights. A column of enhanced density plasma, exceeding the density expected from ionization by primary beam electrons, was observed in a large vacuum system at low magnetic fields (1 to 1.5 G) and low ambient pressures (10 to the minus 6 to 10 to the minus 5 torr). The peak luminosity of the discharge was about 10 times that of the beam alone, and the radius increased by a factor of three. In the absence of the discharge, RF emission is observed at 1.1 to 1.2 times the cyclotron frequency, and a strong band of RF noise with upper frequency cutoff at about the cyclotron frequency is observed in the discharge mode, along with higher frequency noise at or near the plasma frequency. The onset of the plasma discharge is critically dependent on beam current. The described results agree with observations obtained at much higher densities and magnetic fields in fusion research studies.

  13. Non-Thermal Electron Energization from Magnetic Reconnection in Laser-Driven Plasmas

    CERN Document Server

    Totorica, Samuel; Fiuza, Frederico

    2016-01-01

    The possibility of studying non-thermal electron energization in laser-driven plasma experiments of magnetic reconnection is studied using two- and three-dimensional particle-in-cell simulations. It is demonstrated that non-thermal electrons with energies more than an order of magnitude larger than the initial thermal energy can be produced in plasma conditions currently accessible in the laboratory. Electrons are accelerated by the reconnection electric field, being injected at varied distances from the X-points, and in some cases trapped in plasmoids, before escaping the finite-sized system. Trapped electrons can be further energized by the electric field arising from the motion of the plasmoid. This acceleration gives rise to a non-thermal electron component that resembles a power-law spectrum, containing up to ~ 8% of the initial energy of the interacting electrons and ~ 24 % of the initial magnetic energy. Estimates of the maximum electron energy and of the plasma conditions required to observe suprather...

  14. Simulation of cold magnetized plasmas with the 3D electromagnetic software CST Microwave Studio®

    Directory of Open Access Journals (Sweden)

    Louche Fabrice

    2017-01-01

    Full Text Available Detailed designs of ICRF antennas were made possible by the development of sophisticated commercial 3D codes like CST Microwave Studio® (MWS. This program allows for very detailed geometries of the radiating structures, but was only considering simple materials like equivalent isotropic dielectrics to simulate the reflection and the refraction of RF waves at the vacuum/plasma interface. The code was nevertheless used intensively, notably for computing the coupling properties of the ITER ICRF antenna. Until recently it was not possible to simulate gyrotropic medias like magnetized plasmas, but recent improvements have allowed programming any material described by a general dielectric or/and diamagnetic tensor. A Visual Basic macro was developed to exploit this feature and was tested for the specific case of a monochromatic plane wave propagating longitudinally with respect to the magnetic field direction. For specific cases the exact solution can be expressed in 1D as the sum of two circularly polarized waves connected by a reflection coefficient that can be analytically computed. Solutions for stratified media can also be derived. This allows for a direct comparison with MWS results. The agreement is excellent but accurate simulations for realistic geometries require large memory resources that could significantly restrict the possibility of simulating cold plasmas to small-scale machines.

  15. Dust-acoustic shock waves in a charge varying electronegative magnetized dusty plasma with nonthermal ions: Application to Halley Comet plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tribeche, Mouloud; Bacha, Mustapha [Plasma Physics Group (PPG), Theoretical Physics Laboratory (TPL), Faculty of Physics, University of Bab-Ezzouar, USTHB, B. P. 32, El Alia, Algiers 16111 (Algeria)

    2013-10-15

    Weak dust-acoustic waves (DAWs) are addressed in a nonthermal charge varying electronegative magnetized dusty plasmas with application to the Halley Comet. A weakly nonlinear analysis is carried out to derive a Korteweg-de Vries-Burger equation. The positive ion nonthermality, the obliqueness, and magnitude of the magnetic field are found to modify the dispersive and dissipative properties of the DA shock structure. Our results may aid to explain and interpret the nonlinear oscillations that may occur in the Halley Comet Plasma.

  16. Electromagnetic radiation from filamentary sources in the presence of axially magnetized cylindrical plasma scatterers

    Energy Technology Data Exchange (ETDEWEB)

    Es’kin, V. A.; Ivoninsky, A. V.; Kudrin, A. V., E-mail: kud@rf.unn.ru; Popova, L. L. [Lobachevsky University (Russian Federation)

    2017-02-15

    Electromagnetic radiation from filamentary electric-dipole and magnetic-current sources of infinite length in the presence of gyrotropic cylindrical scatterers in the surrounding free space is studied. The scatterers are assumed to be infinitely long, axially magnetized circular plasma columns parallel to the axis of the filamentary source. The field and the radiation pattern of each source are calculated in the case where the source frequency is equal to one of the surface plasmon resonance frequencies of the cylindrical scatterers. It is shown that the presence of even a single resonant magnetized plasma scatterer of small electrical radius or a few such scatterers significantly affects the total fields of the filamentary sources, so that their radiation patterns become essentially different from those in the absence of scatterers or the presence of isotropic scatterers of the same shape and size. It is concluded that the radiation characteristics of the considered sources can efficiently be controlled using their resonance interaction with the neighboring gyrotropic scatterers.

  17. Voyager 2 solar plasma and magnetic field spectral analysis for intermediate data sparsity

    Science.gov (United States)

    Gallana, Luca; Fraternale, Federico; Iovieno, Michele; Fosson, Sophie M.; Magli, Enrico; Opher, Merav; Richardson, John D.; Tordella, Daniela

    2016-05-01

    The Voyager probes are the furthest, still active, spacecraft ever launched from Earth. During their 38 year trip, they have collected data regarding solar wind properties (such as the plasma velocity and magnetic field intensity). Unfortunately, a complete time evolution of the measured physical quantities is not available. The time series contains many gaps which increase in frequency and duration at larger distances. The aim of this work is to perform a spectral and statistical analysis of the solar wind plasma velocity and magnetic field using Voyager 2 data measured in 1979, when the gap density is between the 30% and 50%. For these gap densities, we show the spectra of gapped signals inherit the characteristics of the data gaps. In particular, the algebraic decay of the intermediate frequency range is underestimated and discrete peaks result not from the underlaying data but from the gap sequence. This analysis is achieved using five different data treatment techniques coming from the multidisciplinary context: averages on linearly interpolated subsets, correlation without data interpolation, correlation of linearly interpolated data, maximum likelihood data reconstruction, and compressed sensing spectral estimation. With five frequency decades, the spectra we obtained have the largest frequency range ever computed at five astronomical units from the Sun; spectral exponents have been determined for all the components of the velocity and magnetic field fluctuations. Void analysis is also useful in recovering other spectral properties such as micro and integral scales.

  18. Enhancement of X-ray Production in Z-Pinch Plasmas Using Magnetic Fields

    Science.gov (United States)

    Edison, N. S.; Etlicher, B.; Attelan, S.; Rouillé, C.; Chuvatin, A. S.; Aliaga, R.

    1994-03-01

    We are investigating the effects of an axial magnetic field to stabilize an aluminum vapor z-pinch. An aluminum plasma jet is created from an exploding foil in a DC magnetic field (Bz0 ≤ 300 G). The applied field is small compared to the azimuthal field, Bz0 ≫ Bϑ, and is intended to reduce the growth of instabilities during the compression phase. The pinch is driven by a 2 Ω, 0.1 TW generator (250 kA in 80 ns). Additionally, a micron sized wire may be placed on the pinch axis leading to the plasma-on-wire (POW) configuration. Qualitatively, increasing the axial magnetic field improves the pinch with the m=1 instabilities becoming negligible for fields higher than 150 G. We find that the externally applied fields can enhance x-ray production up to a critical field. Above this critical field x-ray emission decreases even though the pulse length of the radiation may still be increasing. As the applied field increases, the period of x-ray emission increases with the harder spectrum affected the least. The x-ray yield peaks for the POW and Al jet alone configurations at 150 G and 50 G respectively. Diagnostics include filtered PIN x-ray diodes, time-resolved schlieren photography, and time-integrated multiple filtered pinholes. We will present the results comparing the POW and aluminum jet configurations described above.

  19. Laser-driven, magnetized quasi-perpendicular collisionless shocks on the Large Plasma Device

    Energy Technology Data Exchange (ETDEWEB)

    Schaeffer, D. B., E-mail: dschaeffer@physics.ucla.edu; Everson, E. T.; Bondarenko, A. S.; Clark, S. E.; Constantin, C. G.; Vincena, S.; Van Compernolle, B.; Tripathi, S. K. P.; Gekelman, W.; Niemann, C. [Department of Physics and Astronomy, University of California - Los Angeles, Los Angeles, California 90095 (United States); Winske, D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-05-15

    The interaction of a laser-driven super-Alfvénic magnetic piston with a large, preformed magnetized ambient plasma has been studied by utilizing a unique experimental platform that couples the Raptor kJ-class laser system [Niemann et al., J. Instrum. 7, P03010 (2012)] to the Large Plasma Device [Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] at the University of California, Los Angeles. This platform provides experimental conditions of relevance to space and astrophysical magnetic collisionless shocks and, in particular, allows a detailed study of the microphysics of shock formation, including piston-ambient ion collisionless coupling. An overview of the platform and its capabilities is given, and recent experimental results on the coupling of energy between piston and ambient ions and the formation of collisionless shocks are presented and compared to theoretical and computational work. In particular, a magnetosonic pulse consistent with a low-Mach number collisionless shock is observed in a quasi-perpendicular geometry in both experiments and simulations.

  20. Multichannel tunable filter properties of 1D magnetized ternary plasma photonic crystal in the presence of evanescent wave

    Science.gov (United States)

    Awasthi, Suneet Kumar; Panda, Ranjita; Shiveshwari, Laxmi

    2017-07-01

    The multichannel tunable filter properties of one-dimensional ternary plasma photonic crystal composed of magnetized plasma and lossless dielectric have been theoretically investigated using transfer matrix method in the microwave region. The proposed filters possess 2N - 2 comb-like sharp resonant peaks also called transmission channels for N > 1 in transmission spectra in the absence and presence of an external magnetic field. Due to the coupling between evanescent waves and propagating modes in plasma and dielectric layers, respectively, 2N - 2 transmission channels are found without the addition of any defect, enabling the structure to work as a multichannel filter. Next, the filter properties can be made tunable by the application of an external magnetic field, i.e., channel frequency can either be red or blue shifted depending upon the orientation of an external magnetic field. The number of channels and their positions can also be modulated by changing the number of periods (N) and the incident angle (θo), respectively, for both transverse electric (TE) and transverse magnetic (TM) modes besides other parameters such as plasma collision frequency, thickness of the plasma layer, plasma frequency, etc.