Implicit particle simulation of electromagnetic plasma phenomena
International Nuclear Information System (INIS)
Kamimura, T.; Montalvo, E.; Barnes, D.C.; Leboeuf, J.N.; Tajima, T.
1986-11-01
A direct method for the implicit particle simulation of electromagnetic phenomena in magnetized, multi-dimensional plasmas is developed. The method is second-order accurate for ωΔt < 1, with ω a characteristic frequency and time step Δt. Direct time integration of the implicit equations with simplified space differencing allows the consistent inclusion of finite particle size. Decentered time differencing of the Lorentz force permits the efficient simulation of strongly magnetized plasmas. A Fourier-space iterative technique for solving the implicit field corrector equation, based on the separation of plasma responses perpendicular and parallel to the magnetic field and longitudinal and transverse to the wavevector, is described. Wave propagation properties in a uniform plasma are in excellent agreement with theoretical expectations. Applications to collisionless tearing and coalescence instabilities further demonstrate the usefulness of the algorithm. (author)
Macroscale implicit electromagnetic particle simulation of magnetized plasmas
International Nuclear Information System (INIS)
Tanaka, Motohiko.
1988-01-01
An electromagnetic and multi-dimensional macroscale particle simulation code (MACROS) is presented which enables us to make a large time and spatial scale kinetic simulation of magnetized plasmas. Particle ions, finite mass electrons with the guiding-center approximation and a complete set of Maxwell equations are employed. Implicit field-particle coupled equations are derived in which a time-decentered (slightly backward) finite differential scheme is used to achieve stability for large time and spatial scales. It is shown analytically that the present simulation scheme suppresses high frequency electromagnetic waves and that it accurately reproduces low frequency waves in the plasma. These properties are verified by numerical examination of eigenmodes in a 2-D thermal equilibrium plasma and by that of the kinetic Alfven wave. (author)
A simulation of low-frequency electromagnetic phenomena in kinetic plasmas of three dimensions
International Nuclear Information System (INIS)
Tanaka, Motohiko
1993-01-01
An advanced kinetic simulation method has been developed and implemented in the HIDENEK code to study large space-scale, low-frequency electromagnetic phenomena occurring in inhomogeneous plasmas. The present method is specially designed for high magnetic field (ω ce ≥ω pe ), inhomogeneous plasma simulations. The guiding-center approximation with magnetic drifts is adopted to the perpendicular motion of the electrons, whereas the inertia effect is retained in their parallel motion. Also, a slightly backward time-decentered scheme is introduced to the equations of motion and the Maxwell equations. These equations are combined to yield the full-implicit, coupled field-particle equations which allow us to determine the future electromagnetic field in a large time step compared to the electron time scales with the diamagnetic drift and magnetization currents being included. As a demonstration of the present simulation method, three physics applications are shown for the electromagnetic beam-plasma instability, the temperature anisotropy-driven Alfven-ion-cyclotron instability, and the external kind instability of the peaked-density current beam. A remarkable pitch-angle scattering of the ions is observed in the first two applications in association with the plasma instabilities. In the third application to an inhomogeneous, finite-beta plasma of the three dimensions, a helical deformation is shown to take place to the initially straight beam and magnetic axis in an ideal magnetohydrodynamic time scale. 36 refs., 12 figs., 1 tab
International Nuclear Information System (INIS)
Tanaka, Motohiko; Sato, T.; Murakami, S.; Takamaru, H.
1991-06-01
An implicit, electromagnetic particle (kinetic) simulation method is presented that can deal with multi-dimensional, inhomogeneous and finite beta plasmas in large space and time scales. To include the diamagnetic effects in strongly magnetized (ω ce≥ ω pe ) and inhomogeneous, kinetic plasmas of the large scales, full-implicit 'directly-coupled field-particle equations' are derived by using the backward time-decentered scheme and the guiding center approximation with the magnetic drifts about the electron perpendicular motion. This algorithm has been implemented for studies of inhomogeneous and magnetized plasmas of three-dimensions. The basic algorithm of the code is described and several physics applications are shown for the Alfven-ion-cyclotron instability and kink instability of the peaked density ion beam. (author)
Three-dimensional electromagnetic solitary waves in an underdense plasma in PIC simulations
International Nuclear Information System (INIS)
Bulanov, Sergei; Esirkepov, Timur; Nishihara, Katsunobu; Pegoraro, Francesco
2002-01-01
A three-dimensional sub-cycle relativistic electromagnetic soliton has been observed for the first time in a 3D Particle-in-Cell simulation of the propagation of an intense short laser pulse in an underdense plasma. The structure of the 3D soliton is identified. It resembles an oscillating electric dipole and has a strong charge separation and toroidal magnetic field component. We call this structure a TM-soliton (transverse magnetic). The 3D TM-soliton resembles a 2D P-soliton in the plane of electric field polarization, and a 2D S-soliton in the perpendicular plane. The core of the soliton is positively charged on average in time, and this results in its Coulomb explosion and in ion heating. Then the soliton evolves into a post-soliton, which is a slowly expanding quasi-neutral cavity in the plasma
A domain decomposition method for pseudo-spectral electromagnetic simulations of plasmas
International Nuclear Information System (INIS)
Vay, Jean-Luc; Haber, Irving; Godfrey, Brendan B.
2013-01-01
Pseudo-spectral electromagnetic solvers (i.e. representing the fields in Fourier space) have extraordinary precision. In particular, Haber et al. presented in 1973 a pseudo-spectral solver that integrates analytically the solution over a finite time step, under the usual assumption that the source is constant over that time step. Yet, pseudo-spectral solvers have not been widely used, due in part to the difficulty for efficient parallelization owing to global communications associated with global FFTs on the entire computational domains. A method for the parallelization of electromagnetic pseudo-spectral solvers is proposed and tested on single electromagnetic pulses, and on Particle-In-Cell simulations of the wakefield formation in a laser plasma accelerator. The method takes advantage of the properties of the Discrete Fourier Transform, the linearity of Maxwell’s equations and the finite speed of light for limiting the communications of data within guard regions between neighboring computational domains. Although this requires a small approximation, test results show that no significant error is made on the test cases that have been presented. The proposed method opens the way to solvers combining the favorable parallel scaling of standard finite-difference methods with the accuracy advantages of pseudo-spectral methods
Electromagnetic behaviour of a plasma in fluid and relativistic regimes: simulation code R H E A
International Nuclear Information System (INIS)
Bonnaud, G.; Dussy, S.; Lefebvre, E.; Bouchut, F.
1998-01-01
This report presents a numerical model to simulate the electromagnetic processes involved by electrically-charged relativistic fluids. The physical model is first given. Second, the numerical methods are explained with the various packages of the code RHEA, with indication methods are explained with the various packages of the code RHEA, with indication of its performances, within a 1.5.- dimensional framework. Results from test-simulations are shown to validate the use of the code, for both academic situations and realistic context of laser-plasma interaction, for which the code has been designed: the non-linear phenomena in the context of inertial confinement fusion and the ultra-intense laser pulses. (author)
A conservative scheme for electromagnetic simulation of magnetized plasmas with kinetic electrons
Bao, J.; Lin, Z.; Lu, Z. X.
2018-02-01
A conservative scheme has been formulated and verified for gyrokinetic particle simulations of electromagnetic waves and instabilities in magnetized plasmas. An electron continuity equation derived from the drift kinetic equation is used to time advance the electron density perturbation by using the perturbed mechanical flow calculated from the parallel vector potential, and the parallel vector potential is solved by using the perturbed canonical flow from the perturbed distribution function. In gyrokinetic particle simulations using this new scheme, the shear Alfvén wave dispersion relation in the shearless slab and continuum damping in the sheared cylinder have been recovered. The new scheme overcomes the stringent requirement in the conventional perturbative simulation method that perpendicular grid size needs to be as small as electron collisionless skin depth even for the long wavelength Alfvén waves. The new scheme also avoids the problem in the conventional method that an unphysically large parallel electric field arises due to the inconsistency between electrostatic potential calculated from the perturbed density and vector potential calculated from the perturbed canonical flow. Finally, the gyrokinetic particle simulations of the Alfvén waves in sheared cylinder have superior numerical properties compared with the fluid simulations, which suffer from numerical difficulties associated with singular mode structures.
Scattering of electromagnetic waves into plasma oscillations via plasma particles
International Nuclear Information System (INIS)
Lin, A.T.; Dawson, J.M.
1975-01-01
A plasma subjected to an intense electromagnetic wave can exhibit a large number of parametric instabilities. An interesting example which has received little attention is the decay of the electromagnetic wave into a plasma oscillation with the excess energy and momentum being carried off by electrons. This process has been simulated on a one-and-two-halves dimensional electromagnetic code. The incident electromagnetic wave had a frequency near the plasma frequency so that decay into a plasma oscillation and a backscattered electromagnetic wave was excluded. As expected, the threshold for this instability was very large , so it is unlikely that this instability is competitive in most laser plasmas. Nevertheless, the physical mechanism involved provides a means for absorption of laser light and acceleration of particles in a plasma containing large amplitude plasma oscillations
International Nuclear Information System (INIS)
Neubert, T.; Miller, R.H.; Buneman, O.; Nishikawa, K.I.
1992-01-01
The dynamics of low-β plasma clouds moving perpendicular to an ambient magnetic field in vacuum and in a background plasma is simulated by means of a three-dimensional, electromagnetic, and relativistic particle simulation code. The simulations show the formation of the space charge sheaths at the sides of the cloud with the associated polarization electric field which facilitate the cross-field propagation, as well as the sheaths at the front and rear end of the cloud caused by the larger ion Larmor radius, which allows ions to move ahead and lag behind the electrons as they gyrate. Results on the cloud dynamics and electromagnetic radiation include the following: (1) In a background plasma, electron and ion sheaths expand along the magnetic field at the same rate, whereas in vacuum the electron sheath expands much faster than the ion sheath. (2) Sheath electrons are accelerated up to relativistic energies. This result indicates that artificial plasma clouds released in the ionosphere or magnetosphere may generate optical emissions (aurora) as energetic sheath electrons scatter in the upper atmosphere. (3) The expansion of the electron sheaths is analogous to the ejection of high-intensity electron beams from spacecraft. (4) Second-order and higher-order sheaths are formed which extend out into the ambient plasma. (5) Formation of the sheaths and the polarization field reduces the forward momentum of the cloud. (6) The coherent component of the particle gyromotion is damped in time as the particles establish a forward directed drift velocity. (7) The coherent particle gyrations generate electromagnetic radiation
DOD-SBIR Structured Multi-Resolution PIC Code for Electromagnetic Plasma Simulations, Final Report
Energy Technology Data Exchange (ETDEWEB)
Vay, J L; Grote, D P; Friedman, A
2010-04-22
A novel electromagnetic solver with mesh refinement capability was implemented in Warp. The solver allows for calculations in 2-1/2 and 3 dimensions, includes the standard Yee stencil, and the Cole-Karkkainen stencil for lower numerical dispersion along the principal axes. Warp implementation of the Cole-Karkkainen stencil includes an extension to perfectly matched layers (PML) for absorption of waves, and is preserving the conservation property of charge conserving current deposition schemes, like the Buneman-Villanesor and Esirkepov methods. Warp's mesh refinement framework (originally developed for electrostatic calculations) was augmented to allow for electromagnetic capability, following the methodology presented in [1] extended to an arbitrary number of refinement levels. Other developments include a generalized particle injection method, internal conductors using stair-cased approximation, and subcycling of particle pushing. The solver runs in parallel using MPI message passing, with a choice at runtime of 1D, 2D and 3D domain decomposition, and is shown to scale linearly on a test problem up-to 32,768 CPUs. The novel solver was tested on the modeling of filamentation instability, fast ignition, ion beam induced plasma wake, and laser plasma acceleration.
Ultrarelativistic electromagnetic pulses in plasmas
Ashour-Abdalla, M.; Leboeuf, J. N.; Tajima, T.; Dawson, J. M.; Kennel, C. F.
1981-01-01
The physical processes of a linearly polarized electromagnetic pulse of highly relativistic amplitude in an underdense plasma accelerating particles to very high energies are studied through computer simulation. An electron-positron plasma is considered first. The maximum momenta achieved scale as the square of the wave amplitude. This acceleration stops when the bulk of the wave energy is converted to particle energy. The pulse leaves behind as a wake a vacuum region whose length scales as the amplitude of the wave. The results can be explained in terms of a snow plow or piston-like action of the radiation on the plasma. When a mass ratio other than unity is chosen and electrostatic effects begin to play a role, first the ion energy increases faster than the electron energy and then the electron energy catches up later, eventually reaching the same value.
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.
Simulation of cold magnetized plasmas with the 3D electromagnetic software CST Microwave Studio®
Louche, Fabrice; Křivská, Alena; Messiaen, André; Wauters, Tom
2017-10-01
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.
International Nuclear Information System (INIS)
Tanaka, M.; Sato, T.
1985-01-01
A new implicit macroscale electromagnetic particle simulation code (MARC) which allows a large scale length and a time step in multi-dimensions is described. Finite mass electrons and ions are used with relativistic version of the equation of motion. The electromagnetic fields are solved by using a complete set of Maxwell equations. For time integration of the field equations, a decentered (backward) finite differencing scheme is employed with the predictor - corrector method for small noise and super-stability. It is shown both in analytical and numerical ways that the present scheme efficiently suppresses high frequency electrostatic and electromagnetic waves in a plasma, and that it accurately reproduces low frequency waves such as ion acoustic waves, Alfven waves and fast magnetosonic waves. The present numerical scheme has currently been coded in three dimensions for application to a new tokamak current-drive method by means of relativistic electron beam injection. Some remarks of the proper macroscale code application is presented in this paper
Plasma scattering of electromagnetic radiation
Sheffield, John
1975-01-01
Plasma Scattering of Electromagnetic Radiation covers the theory and experimental application of plasma scattering. The book discusses the basic properties of a plasma and of the interaction of radiation with a plasma; the relationship between the scattered power spectrum and the fluctuations in plasma density; and the incoherent scattering of low-temperature plasma. The text also describes the constraints and problems that arise in the application of scattering as a diagnostic technique; the characteristic performance of various dispersion elements, image dissectors, and detectors; and the ge
Electromagnetic radiation from beam-plasma instabilities
Pritchett, P. L.; Dawson, J. M.
1983-01-01
A computer simulation is developed for the generation of electromagnetic radiation in an electron beam-plasma interaction. The plasma is treated as a two-dimensional finite system, and effects of a continuous nonrelativistic beam input are accounted for. Three momentum and three field components are included in the simulation, and an external magnetic field is excluded. EM radiation generation is possible through interaction among Langmuir oscillations, ion-acoustic waves, and the electromagnetic wave, producing radiation perpendicular to the beam. The radiation is located near the plasma frequency, and polarized with the E component parallel to the beam. The scattering of Langmuir waves caused by ion-acoustic fluctuations generates the radiation. Comparison with laboratory data for the three-wave interactions shows good agreement in terms of the radiation levels produced, which are small relative to the plasma thermal energy.
International Nuclear Information System (INIS)
Tsiklauri, David
2011-01-01
High-resolution (sub-Debye length grid size and 10 000 particle species per cell), 1.5D particle-in-cell, relativistic, fully electromagnetic simulations are used to model electromagnetic wave emission generation in the context of solar type III radio bursts. The model studies generation of electromagnetic waves by a super-thermal, hot beam of electrons injected into a plasma thread that contains uniform longitudinal magnetic field and a parabolic density gradient. In effect, a single magnetic line connecting Sun to Earth is considered, for which five cases are studied. (i) We find that the physical system without a beam is stable and only low amplitude level electromagnetic drift waves (noise) are excited. (ii) The beam injection direction is controlled by setting either longitudinal or oblique electron initial drift speed, i.e., by setting the beam pitch angle (the angle between the beam velocity vector and the direction of background magnetic field). In the case of zero pitch angle, i.e., when v-vector b ·E-vector perpendicular =0, the beam excites only electrostatic, standing waves, oscillating at local plasma frequency, in the beam injection spatial location, and only low level electromagnetic drift wave noise is also generated. (iii) In the case of oblique beam pitch angles, i.e., when v-vector b ·E-vector perpendicular =0, again electrostatic waves with same properties are excited. However, now the beam also generates the electromagnetic waves with the properties commensurate to type III radio bursts. The latter is evidenced by the wavelet analysis of transverse electric field component, which shows that as the beam moves to the regions of lower density and hence lower plasma frequency, frequency of the electromagnetic waves drops accordingly. (iv) When the density gradient is removed, an electron beam with an oblique pitch angle still generates the electromagnetic radiation. However, in the latter case no frequency decrease is seen. (v) Since in most of
Electromagnetic separator of plasma
International Nuclear Information System (INIS)
Gasilin, V.V.; Nezovibatko, Yu.N.; Poklepach, G.S.; Shvets, O.M.; Taran, V.S.; Tereshin, V.I.
2005-01-01
The progress in the widespread utilization of the PVD methods is determined in many respects by the plasma quality and, therefore, the necessity of an application of plasma separators, in particular magnetic separators. One needs to note that traditional magnetic separators have a number of problems their using, namely their unwieldiness, the presence of the isolated cameras and so on. We have proposed, manufactured and investigated the simple separator of plasma that doesn't require using additional cameras. As a source of metallic plasma the standard cathode vaporizer in the installation 'BULAT 6' was in use. Plasma stream from the cathode flowed through the not protected by isolation spiral solenoid. The solenoid input (from the cathode side) was under floating potential. The solenoid output was connected to the autonomous power supply system. The solenoid was prepared with stride winding and 90 degree turn. The solenoid current was 20-90 A and the solenoid voltage with respect to the vessel (earth) was +15 V. In this case drifting charged particles could freely fly out from the interior solenoid region to its boundary. The glow of the turned flow of plasma was observed during the supplying of the cathode and the solenoid. Plasma flow was separated from the coils and extended along the axis of solenoid. One can assume that this device ensures radial electric with respect to the bulk of plasma (the diameter of the bulk of plasma is comparable with the cathode diameter), the toroidal magnetic field, produced by solenoid, was of an order of 20 Oe. Magnetic field strength was sufficient for the magnetization of electrons, but it was rather small for magnetizing the ions and charged micro-droplets. The experiments carried out with aluminum cathode on the deposition of coatings at the stainless steel substrate have shown the high effectiveness of this separator operation. Coatings without droplets were obtained also on the glass substrate with HF- displacement
International Nuclear Information System (INIS)
Lichters, R.; Pfund, R.E.W.; Meyer-ter-Vehn, J.
1997-08-01
The code LPIC++ presented here, is based on a one-dimensional, electromagnetic, relativistic PIC code that has originally been developed by one of the authors during a PhD thesis at the Max-Planck-Institut fuer Quantenoptik for kinetic simulations of high harmonic generation from overdense plasma surfaces. The code uses essentially the algorithm of Birdsall and Langdon and Villasenor and Bunemann. It is written in C++ in order to be easily extendable and has been parallelized to be able to grow in power linearly with the size of accessable hardware, e.g. massively parallel machines like Cray T3E. The parallel LPIC++ version uses PVM for communication between processors. PVM is public domain software, can be downloaded from the world wide web. A particular strength of LPIC++ lies in its clear program and data structure, which uses chained lists for the organization of grid cells and enables dynamic adjustment of spatial domain sizes in a very convenient way, and therefore easy balancing of processor loads. Also particles belonging to one cell are linked in a chained list and are immediately accessable from this cell. In addition to this convenient type of data organization in a PIC code, the code shows excellent performance in both its single processor and parallel version. (orig.)
Particle Simulation of Pulsed Plasma Thruster Plumes
National Research Council Canada - National Science Library
Boyd, Ian
2002-01-01
.... Our modeling had made progress in al aspects of simulating these complex devices including Teflon ablation, plasma formation, electro-magnetic acceleration, plume expansion, and particulate transport...
Yu, Minghao; Takahashi, Yusuke; Kihara, Hisashi; Abe, Ken-ichi; Yamada, Kazuhiko; Abe, Takashi
2014-12-01
Numerical investigation of nonequilibrium inductively coupled plasma (ICP) flow was carried out to study the physical properties of the flow inside a 10-kW ICP torch with the working gas being nitrogen. The flow field was described by two-dimensional compressible axisymmetric Navier-Stokes (N-S) equations that took into account 5 species and 8 chemical reactions. The magnetic vector-potential equations were tightly coupled with the flow-field equations to describe the heating process by inductive discharge. A four-temperature model was adopted to model thermal nonequilibrium process in the discharge torch. The characteristics of ICP flow such as thermal nonequilibrium, inductive discharge, and strong effects of Lorentz forces became clear through the present study.
Energy Technology Data Exchange (ETDEWEB)
Bonnaud, G.; Dussy, S.; Lefebvre, E. [CEA Bruyeres-le-Chatel, 91 (France). Dept. de Physique Theorique et Appliquee; Bouchut, F. [Orleans Univ., 45 (France). Dept. de Mathematiques, UMR CNRS
1998-12-31
This report presents a numerical model to simulate the electromagnetic processes involved by electrically-charged relativistic fluids. The physical model is first given. Second, the numerical methods are explained with the various packages of the code RHEA, with indication methods are explained with the various packages of the code RHEA, with indication of its performances, within a 1.5.- dimensional framework. Results from test-simulations are shown to validate the use of the code, for both academic situations and realistic context of laser-plasma interaction, for which the code has been designed: the non-linear phenomena in the context of inertial confinement fusion and the ultra-intense laser pulses. (author) 25 refs.
Yuan, Chengxun; Tian, Ruihuan; Eliseev, S. I.; Bekasov, V. S.; Bogdanov, E. A.; Kudryavtsev, A. A.; Zhou, Zhongxiang
2018-03-01
In this paper, we present investigation of a direct-current discharge with a gridded anode from the point of view of using it as a means of creating plasma coating that could efficiently absorb incident electromagnetic (EM) waves. A single discharge cell consists of two parallel plates, one of which (anode) is gridded. Electrons emitted from the cathode surface are accelerated in the short interelectrode gap and are injected into the post-anode space, where they lose acquired energy on ionization and create plasma. Numerical simulations were used to investigate the discharge structure and obtain spatial distributions of plasma density in the post-anode space. The numerical model of the discharge was based on a simple hybrid approach which takes into account non-local ionization by fast electrons streaming from the cathode sheath. Specially formulated transparency boundary conditions allowed performing simulations in 1D. Simulations were carried out in air at pressures of 10 Torr and higher. Analysis of the discharge structure and discharge formation is presented. It is shown that using cathode materials with lower secondary emission coefficients can allow increasing the thickness of plasma slabs for the same discharge current, which can potentially enhance EM wave absorption. Spatial distributions of electron density obtained during simulations were used to calculate attenuation of an incident EM wave propagating perpendicularly to the plasma slab boundary. It is shown that plasma created by means of a DC discharge with a gridded anode can efficiently absorb EM waves in the low frequency range (6-40 GHz). Increasing gas pressure results in a broader range of wave frequencies (up to 500 GHz) where a considerable attenuation is observed.
High performance electromagnetic simulation tools
Gedney, Stephen D.; Whites, Keith W.
1994-10-01
Army Research Office Grant #DAAH04-93-G-0453 has supported the purchase of 24 additional compute nodes that were installed in the Intel iPsC/860 hypercube at the Univesity Of Kentucky (UK), rendering a 32-node multiprocessor. This facility has allowed the investigators to explore and extend the boundaries of electromagnetic simulation for important areas of defense concerns including microwave monolithic integrated circuit (MMIC) design/analysis and electromagnetic materials research and development. The iPSC/860 has also provided an ideal platform for MMIC circuit simulations. A number of parallel methods based on direct time-domain solutions of Maxwell's equations have been developed on the iPSC/860, including a parallel finite-difference time-domain (FDTD) algorithm, and a parallel planar generalized Yee-algorithm (PGY). The iPSC/860 has also provided an ideal platform on which to develop a 'virtual laboratory' to numerically analyze, scientifically study and develop new types of materials with beneficial electromagnetic properties. These materials simulations are capable of assembling hundreds of microscopic inclusions from which an electromagnetic full-wave solution will be obtained in toto. This powerful simulation tool has enabled research of the full-wave analysis of complex multicomponent MMIC devices and the electromagnetic properties of many types of materials to be performed numerically rather than strictly in the laboratory.
PLASMA EMISSION BY NONLINEAR ELECTROMAGNETIC PROCESSES
Energy Technology Data Exchange (ETDEWEB)
Ziebell, L. F.; Petruzzellis, L. T.; Gaelzer, R. [Instituto de Física, UFRGS, Porto Alegre, RS (Brazil); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park (United States); Pavan, J., E-mail: luiz.ziebell@ufrgs.br, E-mail: laripetruzzellis@yahoo.com.br, E-mail: rudi.gaelzer@ufrgs.br, E-mail: yoonp@umd.edu, E-mail: joel.pavan@ufpel.edu.br [Instituto de Física e Matemática, UFPel, Pelotas, RS (Brazil)
2015-06-20
The plasma emission, or electromagnetic (EM) radiation at the plasma frequency and/or its harmonic(s), is generally accepted as the radiation mechanism responsible for solar type II and III radio bursts. Identification and characterization of these solar radio burst phenomena were done in the 1950s. Despite many decades of theoretical research since then, a rigorous demonstration of the plasma emission process based upon first principles was not available until recently, when, in a recent Letter, Ziebell et al. reported the first complete numerical solution of EM weak turbulence equations; thus, quantitatively analyzing the plasma emission process starting from the initial electron beam and the associated beam-plasma (or Langmuir wave) instability, as well as the subsequent nonlinear conversion of electrostatic Langmuir turbulence into EM radiation. In the present paper, the same problem is revisited in order to elucidate the detailed physical mechanisms that could not be reported in the brief Letter format. Findings from the present paper may be useful for interpreting observations and full-particle numerical simulations.
Electromagnetically Induced Transparency of Magnetized Plasma
International Nuclear Information System (INIS)
Shvets, G.; Wurtele, J.S.
2002-01-01
It is well known that electromagnetic radiation with a frequency equal to the cyclotron frequency of plasma electrons is strongly absorbed by magnetized plasma. It is shown here that this absorption does not occur in the presence of a second, properly de tuned, electromagnetic pump pulse. The plasma can thus be made transparent at the cyclotron frequency. The pump is de tuned from the probe by the plasma frequency. Transparency occurs because the currents induced at the cyclotron frequency by sideband of the pump can cancel the currents induced by the probe. This effect is very similar to electromagnetically-induced transparency of atomic vapors. The essential difference is that the plasma considered here is completely classical, and no quantum mechanical effects are invoked to produce the electromagnetically-induced transparency. The plasma system is significantly more complex than the three level quantum system in particular, a non-local interaction, the plasma oscillation, corresponds to one of the levels. Potential applications of the electromagnetically-induced transparency in plasma will be discussed
Relativistically strong electromagnetic radiation in a plasma
Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Kiriyama, H.; Kondo, K.
2016-03-01
Physical processes in a plasma under the action of relativistically strong electromagnetic waves generated by high-power lasers have been briefly reviewed. These processes are of interest in view of the development of new methods for acceleration of charged particles, creation of sources of bright hard electromagnetic radiation, and investigation of macroscopic quantum-electrodynamical processes. Attention is focused on nonlinear waves in a laser plasma for the creation of compact electron accelerators. The acceleration of plasma bunches by the radiation pressure of light is the most efficient regime of ion acceleration. Coherent hard electromagnetic radiation in the relativistic plasma is generated in the form of higher harmonics and/or electromagnetic pulses, which are compressed and intensified after reflection from relativistic mirrors created by nonlinear waves. In the limit of extremely strong electromagnetic waves, radiation friction, which accompanies the conversion of radiation from the optical range to the gamma range, fundamentally changes the behavior of the plasma. This process is accompanied by the production of electron-positron pairs, which is described within quantum electrodynamics theory.
Analysis of plasma behavior and electro-magnetic interaction between plasma and device
International Nuclear Information System (INIS)
Kobayashi, Tomofumi
1980-01-01
A simulation program for the analysis of plasma behavior and the electromagnetic interaction between plasma and device has been developed. The program consists of a part for the analysis of plasma behavior (plasma system) and a part for the analysis of the electro-magnetic interaction between plasma and devices (circuit system). The parameters which connect the plasma system and the circuit system are the electric resistance of plasma, the internal inductance, and the plasma current. For the plasma system, the simultaneous equations which describe the density distribution of plasma particles, the temperature distribution of electrons and ions, and the space-time variation of current density distribution were derived. The one-dimensional plasma column in γ-direction was considered. The electric resistance and the internal inductance can be deduced. The circuit components are a current transformer, a vertical field coil, a quadrupole field coil, a vacuum chamber and others. An equation which describes plasma position and the shape of cross section is introduced. The plasma position can be known by solving the Mukhavatov's formula of equilibrium. By using this program, the build-up process of plasma current in JT-60 was analysed. It was found that the expansion of plasma sub radius and the control of current distribution by gas injection are the effective methods to obtain high temperature and high density plasma. The eddy current induced in a vacuum vessel shields 40 percent of magnetic field made in the plasma region by a vertical field coil. (Kato, T.)
Electromagnetic signals of quark gluon plasma
Indian Academy of Sciences (India)
Successive equilibration of quark degrees of freedom and its effects on electromagnetic signals of quark gluon plasma are discussed. The effects of the variation of vector meson masses and decay widths on photon production from hot strongly interacting matter formed after Pb + Pb and S + Au collisions at CERN SPS ...
Electromagnetic signals of quark gluon plasma
Indian Academy of Sciences (India)
Successive equilibration of quark degrees of freedom and its effects on electromagnetic signals of quark gluon plasma are discussed. ... It has been shown that the present photon spectra measured by WA80 and WA98 Collaborations can not distinguish between the formation of quark matter and hadronic matter in the ...
Plasma physics via particle simulation
International Nuclear Information System (INIS)
Birdsall, C.K.
1981-01-01
Plasmas are studied by following the motion of many particles in applied and self fields, analytically, experimentally and computationally. Plasmas for magnetic fusion energy devices are very hot, nearly collisionless and magnetized, with scale lengths of many ion gyroradii and Debye lengths. The analytic studies of such plasmas are very difficult as the plasma is nonuniform, anisotropic and nonlinear. The experimental studies have become very expensive in time and money, as the size, density and temperature approach fusion reactor values. Computational studies using many particles and/or fluids have complemented both theories and experiments for many years and have progressed to fully three dimensional electromagnetic models, albeit with hours of running times on the fastest largest computers. Particle simulation methods are presented in some detail, showing particle advance from acceleration to velocity to position, followed by calculation of the fields from charge and current densities and then further particle advance, and so on. Limitations due to the time stepping and use of a spatial grid are given, to avoid inaccuracies and instabilities. Examples are given for an electrostatic program in one dimension of an orbit averaging program, and for a three dimensional electromagnetic program. Applications of particle simulations of plasmas in magnetic and inertial fusion devices continue to grow, as well as to plasmas and beams in peripheral devices, such as sources, accelerators, and converters. (orig.)
International Nuclear Information System (INIS)
Sagdeev, R.Z.; Shapiro, V.D.; Shevchenko, V.I.
1980-01-01
An attempt is made to analyze two assumptions of the present theory of plasma turbulence, initiated by an electromagnetic wave, as applied to the problem of heating the plasma target. It has been assumed that in the long-scale region (the region of an electromagnetic wave source) and in the inertia range, separating the source region and the short-wave absorption region, there is a permanent pumping. The first assumption consists in simulating a situation in a plasma target when the Langmuir turbulence arises due to an electromagnetic wave incident on the target. The second assumption is valid only at a very high intensity of plasma waves when their energy is significantly less than the thermal energy of plasma W/nsub(c)T 0 is the frequency of an incident electromagnetic wave). At W approximately equal to nsub(c)T the plasma oscillations, arising due to modulation instability from the electromagnetic pumping wave, fall immediately into the absorption region. A phenomenological theory of such a turbulence, called ''superstrong'', is formulated on the assumption that there is a mechanism of ''mixing up'' plasmon phases as a result of their populating the long-wave density fluctuations
Grudiev, A; Lettry, J; Mattei, S; Paoluzzi, M; Scrivens, R
2014-02-01
Numerical simulation of the CERN LINAC4 H(-) source 2 MHz RF system has been performed taking into account a realistic geometry from 3D Computer Aided Design model using commercial FEM high frequency simulation code. The effect of the plasma has been added to the model by the approximation of a homogenous electrically conducting medium. Electric and magnetic fields, RF power losses, and impedance of the circuit have been calculated for different values of the plasma conductivity. Three different regimes have been found depending on the plasma conductivity: (1) Zero or low plasma conductivity results in RF electric field induced by the RF antenna being mainly capacitive and has axial direction; (2) Intermediate conductivity results in the expulsion of capacitive electric field from plasma and the RF power coupling, which is increasing linearly with the plasma conductivity, is mainly dominated by the inductive azimuthal electric field; (3) High conductivity results in the shielding of both the electric and magnetic fields from plasma due to the skin effect, which reduces RF power coupling to plasma. From these simulations and measurements of the RF power coupling on the CERN source, a value of the plasma conductivity has been derived. It agrees well with an analytical estimate calculated from the measured plasma parameters. In addition, the simulated and measured impedances with and without plasma show very good agreement as well demonstrating validity of the plasma model used in the RF simulations.
Electromagnetic Separator of a Plasma
International Nuclear Information System (INIS)
Gasilin, Vladimir V.; Nezovibat'ko, Yuriy N.; Poklipach, Grigoriy S.; Shvets, Oleg M.; Taran, Valeriy S.; Tereshin, Vladimir I.
2006-01-01
Simple freestanding 90 deg. filter is used for obtaining the metallic vacuum coatings. As the source of metallic plasma adapted standard cathode vaporizer on the installation ''Bulat 6''. Plasma flow from the cathode flowed through the not protected by isolation spiral (solenoid). The solenoid outlet from the side of cathode find under the floating potential. The second solenoid outlet was connected to the autonomous power supply. Solenoid was prepared with the wide interval of the coil winding and with the turning to 90 degrees. Therefore, drifting charged of particle can freely depart from the interior of solenoid outside. The glow of the turned flow of plasma is observed during the supplying to the cathode and the solenoid. Flow is separation from the coils and is extended along the axis of solenoid. In this case over the solenoid flow the current 20-90 A, the voltage of solenoid relative to vessel (earth) + 15 V. We assume, that this device ensures radial electric field relative to the basic nucleus of the plasma (diameter of the nucleus of plasma column it is commensurate with the diameter of cathode) and the current of solenoid creates the longitudinal magnetic field (estimated order 20 oersted). Magnetic field strength is sufficient for the magnetization of electrons, but it is very small for the ions and the charged microdroplets. The carried out experiments on the application of coatings on the dielectric substrate with the use of aluminum and titanium cathodes showed the effectiveness of the work of this separator. Coatings without the drops are obtained also on the glass substrate with HF- displacement. The reflective properties of the metallic films (Ti,Al) on the glass samples were measured
Electromagnetic gyrokinetic simulation in GTS
Ma, Chenhao; Wang, Weixing; Startsev, Edward; Lee, W. W.; Ethier, Stephane
2017-10-01
We report the recent development in the electromagnetic simulations for general toroidal geometry based on the particle-in-cell gyrokinetic code GTS. Because of the cancellation problem, the EM gyrokinetic simulation has numerical difficulties in the MHD limit where k⊥ρi -> 0 and/or β >me /mi . Recently several approaches has been developed to circumvent this problem: (1) p∥ formulation with analytical skin term iteratively approximated by simulation particles (Yang Chen), (2) A modified p∥ formulation with ∫ dtE∥ used in place of A∥ (Mishichenko); (3) A conservative theme where the electron density perturbation for the Poisson equation is calculated from an electron continuity equation (Bao) ; (4) double-split-weight scheme with two weights, one for Poisson equation and one for time derivative of Ampere's law, each with different splits designed to remove large terms from Vlasov equation (Startsev). These algorithms are being implemented into GTS framework for general toroidal geometry. The performance of these different algorithms will be compared for various EM modes.
International Nuclear Information System (INIS)
Jang, D G; Kim, J J; Suk, H; Hur, M S
2012-01-01
When an intense laser beam is focused in a plasma, a plasma wake wave is generated and the oscillatary motion of the plasma electrons produces a strong electromagnetic wave by a Cherenkov-like process. Spectrum of the genetated electromagnetic wave has dependence on the plasma density. In this paper, we propose to use the emitted electromagnetic radiation for plasma diagnostic, which may provide an accurate information for local electron densities of the plasma and will be very useful for three-dimensional plasma density profiles by changing the focal point location of the laser beam. Two-dimensional (2-D) particle-in-cell (PIC) simulation is used to study the correlation between the spectrum of the emitted radiation and plasma density, and the results demonstrate that this method is promising for the electron density measurement in the plasma.
Electromagnetic radiation generated by arcing in low density plasma
Vayner, Boris V.; Ferguson, Dale C.; Snyder, David B.; Doreswamy, C. V.
1996-01-01
An unavoidable step in the process of space exploration is to use high-power, very large spacecraft launched into Earth orbit. Obviously, the spacecraft will need powerful energy sources. Previous experience has shown that electrical discharges occur on the surfaces of a high-voltage array, and these discharges (arcs) are undesirable in many respects. Moreover, any high voltage conductor will interact with the surrounding plasma, and that interaction may result in electrical discharges between the conductor and plasma (or between two conductors with different potentials, for example, during docking and extravehicular activity). One very important aspect is the generation of electromagnetic radiation by arcing. To prevent the negative influence of electromagnetic noise on the operation of spacecraft systems, it seems necessary to determine the spectra and absolute levels of the radiation, and to determine limitations on the solar array bias voltage that depend on the parameters of LEO plasma and the technical requirements of the spacecraft equipment. This report describes the results of an experimental study and computer simulation of the electromagnetic radiation generated by arcing on spacecraft surfaces. A large set of high quality data was obtained during the Solar Array Module Plasma Interaction Experiment (SAMPIE, flight STS-62) and ground test. These data include the amplitudes of current, pulse forms, duration of each arc, and spectra of plasma waves. A theoretical explanation of the observed features is presented in this report too. The elaborated model allows us to determine the parameters of the electromagnetic noise for different frequency ranges, distances from the arcing site, and distinct kinds of plasma waves.
Electromagnetic modes in cold magnetized strongly coupled plasmas
Tkachenko, I. M.; Ortner, J.; Rylyuk, V. M.
1999-01-01
The spectrum of electromagnetic waves propagating in a strongly coupled magnetized fully ionized hydrogen plasma is found. The ion motion and damping being neglected, the influence of the Coulomb coupling on the electromagnetic spectrum is analyzed.
Space plasma simulation chamber
International Nuclear Information System (INIS)
1986-01-01
Scientific results of experiments and tests of instruments performed with the Space Plasma Simulation Chamber and its facility are reviewed in the following six categories. 1. Tests of instruments on board rockets, satellites and balloons. 2. Plasma wave experiments. 3. Measurements of plasma particles. 4. Optical measurements. 5. Plasma production. 6. Space plasms simulations. This facility has been managed under Laboratory Space Plasma Comittee since 1969 and used by scientists in cooperative programs with universities and institutes all over country. A list of publications is attached. (author)
Electromagnetic induction phenomena in plasma systems
International Nuclear Information System (INIS)
Karlovitz, B.
1982-01-01
The phenomenon of electromagnetic induction is considered in complex high temperature plasma systems. Thermal energy of such fully ionized plasma is really energy of the magnetic vortex fields surrounding the randomly moving ions and electrons. In an expanding plasma stream, moving across the containing magnetic field, random thermal motion of the ions and electrons is converted into ordered motion and thereby random magnetic energy of the plasma into magnetic energy of an ordered field. Consequently, in contrast to simple systems consisting of coils and magnets only, an expanding plasma stream can maintain net outflow of ordered magnetic energy from a closed volume for an indefinite length of time. Conversion of thermal energy of plasma into ordered magnetic energy by the thermodynamic expansion process leads to the expectation of a new induction phenomenon: the generation of a unidirectional induced electromotive force of unlimited duration, measured in a closed loop at rest relative to the magnetic field, by the expansion work of the plasma stream. No change is required in the differential form of Maxwell's equations for the existence of this induction phenomenon, only the definition of the concept of rate of change of magnetic flux needs to be modified in the macroscopic equations to correspond to the rate of flow of magnetic energy across a closed surface. An experimental test of the predicted induction phenomenon is proposed
Electromagnetic wave interaction with the auroral plasma
Pau, Jacqueline Tze-Ho
High power radio electromagnetic waves interaction with the auroral plasma has been investigated. Plasma in this auroral region can be illuminated by EM waves for a prolonged period of time and thus, experiences accumulative perturbations and resonances because of its long plasma lifetime, slow transport rates, and weak convection, especially near the peak of the ionospheric electron density profile. A plasma resonance at a specific height in the ionosphere has a corresponding EM wave frequency. These plasma resonances can enhance the local electromagnetic fields, and therefore their interactions with plasma particles leading to turbulences, local heating, density perturbations, and field aligned striations. The non-linear process at the resonance layer also stimulates the emission of electromagnetic waves which appear as the sidebands of the reflected EM wave. These effects are more pronounced when the EM wave frequency is near foF2, the frequency for the resonance near the peak of the ionospheric electron density profile. Optical emissions are also enhanced under such conditions. This thesis describes two major experiments performed at the HIPAS and HAARP facilities, namely the preconditioning and the second harmonic matching experiments. The experimental data confirms the region where the most efficient interaction between the EM waves and the auroral plasma are near the peak of the ionospheric density profile and where the EM wave frequency matches both the local plasma frequency and the second harmonic of the ionospheric electron cyclotron frequency. In the preconditioning experiments, the ionosphere is first pre-conditioned with high power EM wave. This generates field-aligned striations, which in turn reduces the threshold level of the non-linear process at the resonance layer. The spectral features of the sidebands are excited with an effective radiation power (ERP) level of 24 dB less than that normally required. We observed that using the preconditioning
Generation of radiation by intense plasma and electromagnetic undulators
International Nuclear Information System (INIS)
Joshi, C.
1991-10-01
We examine the characteristics of the classical radiation emission resulting from the interaction of a relativistic electron beam that propagates perpendicularly through a large amplitude relativistic plasma wave. Such a study is useful for evaluating the feasibility of using relativistic plasma waves as extremely short wavelength undulators for generating short wavelength radiation. The electron trajectories in a plasma wave undulator and in an ac FEL undulator are obtained using perturbation techniques. The spontaneous radiation frequency spectrum and angular distribution emitted by a single electron oscillating in these two undulators are then calculated. The radiation gain of a copropagating electromagnetic wave is calculated. The approximate analytic results for the trajectories, spontaneous radiation and gain are compared with 3-D simulation results. The characteristics of the plasma wave undulator are compared with the ac FEL undulator and linearly polarized magnetic undulator. 50 refs., 26 figs., 3 tabs
Nonlinear electromagnetic gyrokinetic particle simulations with the electron hybrid model
Nishimura, Y.; Lin, Z.; Chen, L.; Hahm, T.; Wang, W.; Lee, W.
2006-10-01
The electromagnetic model with fluid electrons is successfully implemented into the global gyrokinetic code GTC. In the ideal MHD limit, shear Alfven wave oscillation and continuum damping is demonstrated. Nonlinear electromagnetic simulation is further pursued in the presence of finite ηi. Turbulence transport in the AITG unstable β regime is studied. This work is supported by Department of Energy (DOE) Grant DE-FG02-03ER54724, Cooperative Agreement No. DE-FC02-04ER54796 (UCI), DOE Contract No. DE-AC02-76CH03073 (PPPL), and in part by SciDAC Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas. Z. Lin, et al., Science 281, 1835 (1998). F. Zonca and L. Chen, Plasma Phys. Controlled Fusion 30, 2240 (1998); G. Zhao and L. Chen, Phys. Plasmas 9, 861 (2002).
Simulation of electromagnetic aggression on components
International Nuclear Information System (INIS)
Adoun, G.; Coumar, O.
1997-01-01
Numerical simulation techniques can be used for studying the behaviour of electronic components exposed to electromagnetic aggression. This article discusses CW analysis on a CMOS-technology logic NAND gate under electromagnetic aggression of different amplitudes (2.5 V 5 V), frequencies (100 MHz and 1 GHz) and phase. Numerical simulations were conducted using three codes: Spice code was used for solving electronic circuits, and the Atlas and Dessis codes were used for examining internal component behaviour. (authors)
Pulsed Electromagnetic Acceleration of Plasma: A Review
Thio, Y. C. Francis; Turchi, Peter J.; Markusic, Thomas E.; Cassibry, Jason T.; Sommer, James; Rodgers, Stephen L. (Technical Monitor)
2002-01-01
Much have been learned in the acceleration mechanisms involved in accelerating a plasma electromagnetically in the laboratory over the last 40 years since the early review by Winston Bostik of 1963, but the accumulated understanding is very much scattered throughout the literature. This literature extends back at least to the early sixties and includes Rosenbluth's snowplow model, discussions by Ralph Lovberg, Colgate's boundary-layer model of a current sheet, many papers from the activity at Columbia by Robert Gross and his colleagues, and the relevant, 1-D unsteady descriptions developed from the U. of Maryland theta-pinch studies. Recent progress on the understanding of the pulsed penetration of magnetic fields into collisionless or nearly collisionless plasmas are also be reviewed. Somewhat more recently, we have the two-dimensional, unsteady results in the collisional regime associated with so-called wall-instability in large radius pinch discharges and also in coaxial plasma guns (e.g., Plasma Flow Switch). Among other things, for example, we have the phenomenon of a high- density plasma discharge propagating in a cooaxial gun as an apparently straight sheet (vs paraboloid) because mass re-distribution (on a microsecond timescale) compensates for the 1/r- squared variation of magnetic pressure. We will attempt to collate some of this vast material and bring some coherence tc the development of the subject.
Electromagnetic solitary waves in magnetized plasmas
International Nuclear Information System (INIS)
Hazeltine, R.D.; Holm, D.D.; Morrison, P.J.
1985-03-01
A Hamiltonian formulation, in terms of noncanonical Poisson bracket, is presented for a nonlinear fluid system that includes reduced magnetohydrodynamics and the Hasegawa-Mima equation as limiting cases. The single-helicity and axisymmetric versions possess three nonlinear Casimir invariants, from which a generalized potential can be constructed. Variation of the generalized potential yields a description of exact nonlinear stationary states. The new equilibria, allowing for plasma flow as well as partial electron adiabaticity, are distinct from those found in conventional magnetohydrodynamic theory. They differ from electrostatic stationary states in containing plasma current and magnetic field excitation. One class of steady-state solutions is shown to provide a simple electromagnetic generalization of drift-solitary waves
Broadband electromagnetic environments simulator (EMES)
International Nuclear Information System (INIS)
Pollard, N.
1977-01-01
A new test facility has been developed by Sandia Laboratories for determining the effects of electromagnetic environments on systems and components. The facility is capable of producing uniform, vertically polarized, continuous wave (CW) and pulsed fields over the frequency range of dc to 10 GHz. This broadband capability addresses the electromagnetic radiation (EMR) threat and is ideally suited to computer controlled sweeping and data acquisition. EMES is also capable of producing uniform transient fields having the wave shape and magnitude characteristic of a nuclear electromagnetic pulse (EMP) and near lightning. The design consists of a truncated, triplate, rectangular coaxial transmission line. The spacing between the flat center conductor and the ground planes is 4 meters. The line is terminated in its characteristic impedance of 50 ohms. At frequencies below the first resonance of the facility it behaves as a typical coaxial system. Above resonance, a wall of electromagnetic absorbing material provides a nonreflecting termination. Thus, EMES essentially combines the elements of a transmission line and an anechoic chamber. It will not radiate electromagnetic energy into the surrounding area because it is a shielded transmission line
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
Theory of electromagnetic fluctuations for magnetized multi-species plasmas
Energy Technology Data Exchange (ETDEWEB)
Navarro, Roberto E., E-mail: roberto.navarro@ug.uchile.cl; Muñoz, Víctor [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Araneda, Jaime [Departamento de Física, Universidad de Concepción, Concepción 4070386 (Chile); Moya, Pablo S. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Department of Physics, Catholic University of America, Washington, D. C. 20064 (United States); Viñas, Adolfo F. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Valdivia, Juan A. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro de Estudios Interdisciplinarios Básicos y Aplicados en Complejidad, CEIBA complejidad, Bogotá (Colombia)
2014-09-15
Analysis of electromagnetic fluctuations in plasma provides relevant information about the plasma state and its macroscopic properties. In particular, the solar wind persistently sustains a small but detectable level of magnetic fluctuation power even near thermal equilibrium. These fluctuations may be related to spontaneous electromagnetic fluctuations arising from the discreteness of charged particles. Here, we derive general expressions for the plasma fluctuations in a multi-species plasma following arbitrary distribution functions. This formalism, which generalizes and includes previous works on the subject, is then applied to the generation of electromagnetic fluctuations propagating along a background magnetic field in a plasma of two proton populations described by drifting bi-Maxwellians.
Nonlinear simulation of electromagnetic current diffusive interchange mode turbulence
International Nuclear Information System (INIS)
Yagi, M.; Itoh, S.I.; Fukuyama, A.
1998-01-01
The anomalous transport in toroidal plasmas has been investigated extensively. It is pointed out that the nonlinear instability is important in driving the microturbulence[1], i.e., the self-sustained plasma turbulence. This concept is explained as follows; when the electron motion along the magnetic field line is resisted by the background turbulence, it gives rise to the effective resistivity and enhances the level of the turbulence. The nonlinear simulation of the electrostatic current diffusive interchange mode (CDIM) in the two dimensional sheared slab geometry has been performed as an example. The occurrence of the nonlinear instability and the self-sustainment of the plasma turbulence were confirmed by this simulation[2]. On the other hand, the electromagnetic turbulence is sustained in the high pressure limit. The possibility of the self-organization with more variety has been pointed out[3]. It is important to study the electromagnetic turbulence based on the nonlinear simulation. In this paper, the model equation for the electrostatic CDIM turbulence[2] is extended for both electrostatic and electromagnetic turbulence. (1) Not only E x B convective nonlinearity but also the electromagnetic nonlinearity which is related to the parallel flow are incorporated into the model equation. (2) The electron and ion pressure evolution equations are solved separately, making it possible to distinguish the electron and ion thermal diffusivities. The two dimensional nonlinear simulation of the electromagnetic CDIM is performed based on the extended fluid model. This paper is organized as follows. The model equation is explained in section II. The result of simulation is shown in section III. The conclusion and discussion are given in section IV. (author)
Electromagnetic simulations of tokamaks and stellarators
Energy Technology Data Exchange (ETDEWEB)
Cole, Michael; Mishchenko, Alexey [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Assoziation, Wendelsteinstrasse 1, 17491 Greifswald (Germany)
2014-07-01
A practical fusion reactor will require a plasma β of around 5%. In this range Alfvenic effects become important. Since a practical reactor will also produce energetic alpha particles, the interaction between Alfvenic instabilities and fast ions is of particular interest. We have developed a fluid electron, kinetic ion hybrid model that can be used to study this problem. Compared to fully gyrokinetic electromagnetic codes, hybrid codes offer faster running times and greater flexibility, at the cost of reduced completeness. The model has been successfully verified against the worldwide ITPA Toroidal Alfven Eigenmode (TAE) benchmark, and the ideal MHD code CKA for the internal kink mode in a tokamak. Use of the model can now be turned toward cases of practical relevance. Current work focuses on simulating fishbones in a tokamak geometry, which may be of relevance to ITER, and producing the first non-perturbative self-consistent simulations of TAE in a stellarator, which may be of relevance both to Wendelstein 7-X and any future stellarator reactor. Preliminary results of these studies are presented.
Spectral properties of electromagnetic turbulence in plasmas
Directory of Open Access Journals (Sweden)
D. Shaikh
2009-03-01
Full Text Available We report on the nonlinear turbulent processes associated with electromagnetic waves in plasmas. We focus on low-frequency (in comparison with the electron gyrofrequency nonlinearly interacting electron whistlers and nonlinearly interacting Hall-magnetohydrodynamic (H-MHD fluctuations in a magnetized plasma. Nonlinear whistler mode turbulence study in a magnetized plasma involves incompressible electrons and immobile ions. Two-dimensional turbulent interactions and subsequent energy cascades are critically influenced by the electron whisters that behave distinctly for scales smaller and larger than the electron skin depth. It is found that in whistler mode turbulence there results a dual cascade primarily due to the forward spectral migration of energy that coexists with a backward spectral transfer of mean squared magnetic potential. Finally, inclusion of the ion dynamics, resulting from a two fluid description of the H-MHD plasma, leads to several interesting results that are typically observed in the solar wind plasma. Particularly in the solar wind, the high-time-resolution databases identify a spectral break at the end of the MHD inertial range spectrum that corresponds to a high-frequency regime. In the latter, turbulent cascades cannot be explained by the usual MHD model and a finite frequency effect (in comparison with the ion gyrofrequency arising from the ion inertia is essentially included to discern the dynamics of the smaller length scales (in comparison with the ion skin depth. This leads to a nonlinear H-MHD model, which is presented in this paper. With the help of our 3-D H-MHD code, we find that the characteristic turbulent interactions in the high-frequency regime evolve typically on kinetic-Alfvén time-scales. The turbulent fluctuation associated with kinetic-Alfvén interactions are compressive and anisotropic and possess equipartition of the kinetic and magnetic energies.
Kinetic instabilities in plasmas: from electromagnetic fluctuations to collisionless shocks
International Nuclear Information System (INIS)
Ruyer, Charles
2014-01-01
Collisionless shocks play a major role in powerful astrophysical objects (e.g., gamma-ray bursts, supernova remnants, pulsar winds, etc.), where they are thought to be responsible for non-thermal particle acceleration and radiation. Numerical simulations have shown that, in the absence of an external magnetic field, these self-organizing structures originate from electromagnetic instabilities triggered by high-velocity colliding flows. These Weibel-like instabilities are indeed capable of producing the magnetic turbulence required for both efficient scattering and Fermi-type acceleration. Along with rapid advances in their theoretical understanding, intense effort is now underway to generate collisionless shocks in the laboratory using energetic lasers. In a first part we study the (w,k)-resolved electromagnetic thermal spectrum sustained by a drifting relativistic plasma. In particular, we obtain analytical formulae for the fluctuation spectra, the latter serving as seeds for growing magnetic modes in counterstreaming plasmas. Distinguishing between sub-luminal and supra-luminal thermal fluctuations, we derived analytical formulae of their respective spectral contributions. Comparisons with particle-in-cell (PIC) simulations are made, showing close agreement in the sub-luminal regime along with some discrepancy in the supra-luminal regime. Our formulae are then used to estimate the saturation time of the Weibel instability of relativistic pair plasmas. Our predictions are shown to match 2-D particle-in-cell (PIC) simulations over a three-decade range in flow energy. We then develop a predictive kinetic model of the nonlinear phase of the Weibel instability induced by two counter-streaming, symmetric and non-relativistic ion beams. This self consistent, fully analytical model allows us to follow the evolution of the beams' properties up to a stage close to complete isotropization and thus to shock formation. Its predictions are supported by 2D and 3D particle
Resonant emission of electromagnetic waves by plasma solitons
International Nuclear Information System (INIS)
Mironov, V.A.; Sergeev, A.M.; Khimich, A.V.
1988-01-01
The ability of plasma-wave solitons to radiate electromagnetic waves at the frequency of the natural oscillations of the field is considered. It is shown that this radiation is the main energy dissipation channel for strong plasma turbulence in a magnetoactive plasma. An interpretation is proposed for the artificial radio emission produced when the ionosphere is acted upon by beams of strong electromagnetic waves. The use of this phenomenon for plasma turbulence, particularly in the outer-space plasma near the earth, is discussed
International Nuclear Information System (INIS)
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
Enabling technologies for petascale electromagnetic accelerator simulation
International Nuclear Information System (INIS)
Lee, L-Q; Akcelik, Volkan; Chen, Sheng; Ge Lixin; Prudencio, Ernesto; Schussman, Greg; Uplenchwar, Ravi; Ng, Cho; Ko, Kwok; Luo Xiaojun; Shephard, Mark
2007-01-01
The SciDAC2 accelerator project at SLAC aims to simulate an entire three-cryomodule radio frequency (RF) unit of the International Linear Collider (ILC) main Linac. Petascale computing resources supported by advances in Applied Mathematics (AM) and Computer Science (CS) and INCITE Program are essential to enable such very large-scale electromagnetic accelerator simulations required by the ILC Global Design Effort. This poster presents the recent advances and achievements in the areas of CS/AM through collaborations
On formation of electromagnetic clot of high energy in plasma
Alanakyan, Yu. R.
2017-04-01
It is known that an oscillating electromagnetic field can be localized inside a self-sustaining resonator formed in plasma. In this paper, it is shown that the Maxwell tension of the electromagnetic field can reduce the resonator volume, thereby increasing the energy density of the field considered. This results in the formation of a quasi-stationary structure of high electromagnetic energy density. A similar mechanism explains the ball lightning phenomenon.
Nonlinear generation of ultra-short electromagnetic pulses in plasmas
International Nuclear Information System (INIS)
Isanin, A.; Bulanov, S.S.; Kamenets, F.; Pegoraro, F.
2005-01-01
When a low-frequency relativistic soliton interacts with the electron density modulations of a wake plasma wave, part of the soliton electromagnetic energy is reflected in the form of an extremely short and ultraintense electromagnetic pulse. By computing analytically the spectra of the reflected and of the transmitted electromagnetic pulses, we show that the reflected wave has the form of a single cycle attosecond pulse
Energy Technology Data Exchange (ETDEWEB)
Greenwald, Martin
2011-10-04
Many others in the fusion energy and advanced scientific computing communities participated in the development of this plan. The core planning team is grateful for their important contributions. This summary is meant as a quick overview the Fusion Simulation Program's (FSP's) purpose and intentions. There are several additional documents referenced within this one and all are supplemental or flow down from this Program Plan. The overall science goal of the DOE Office of Fusion Energy Sciences (FES) Fusion Simulation Program (FSP) is to develop predictive simulation capability for magnetically confined fusion plasmas at an unprecedented level of integration and fidelity. This will directly support and enable effective U.S. participation in International Thermonuclear Experimental Reactor (ITER) research and the overall mission of delivering practical fusion energy. The FSP will address a rich set of scientific issues together with experimental programs, producing validated integrated physics results. This is very well aligned with the mission of the ITER Organization to coordinate with its members the integrated modeling and control of fusion plasmas, including benchmarking and validation activities. [1]. Initial FSP research will focus on two critical Integrated Science Application (ISA) areas: ISA1, the plasma edge; and ISA2, whole device modeling (WDM) including disruption avoidance. The first of these problems involves the narrow plasma boundary layer and its complex interactions with the plasma core and the surrounding material wall. The second requires development of a computationally tractable, but comprehensive model that describes all equilibrium and dynamic processes at a sufficient level of detail to provide useful prediction of the temporal evolution of fusion plasma experiments. The initial driver for the whole device model will be prediction and avoidance of discharge-terminating disruptions, especially at high performance, which are a
Mathematical models and numerical simulation in electromagnetism
Bermúdez, Alfredo; Salgado, Pilar
2014-01-01
The book represents a basic support for a master course in electromagnetism oriented to numerical simulation. The main goal of the book is that the reader knows the boundary-value problems of partial differential equations that should be solved in order to perform computer simulation of electromagnetic processes. Moreover it includes a part devoted to electric circuit theory based on ordinary differential equations. The book is mainly oriented to electric engineering applications, going from the general to the specific, namely, from the full Maxwell’s equations to the particular cases of electrostatics, direct current, magnetostatics and eddy currents models. Apart from standard exercises related to analytical calculus, the book includes some others oriented to real-life applications solved with MaxFEM free simulation software.
Wake-Field Wave Resonant Excitation in Magnetized Plasmas by Electromagnetic Pulse
International Nuclear Information System (INIS)
Milant'ev, V.P.; Turikov, V.A.
2006-01-01
In this paper the space charge wave excitation process at electromagnetic pulse propagation along external magnetic field in vicinity of electron cyclotron resonance. In hydrodynamic approach it is obtained an equation for plasma density under ponderomotive force action. With help of this equation we investigated a wake-field wave amplitude dependence from resonance detuning. The numerical simulation using a PIC method electromagnetic pulse propagation process in the resonant conditions was done
Numerical simulation of electromagnetic surface treatment
Sonde, Emmanuel; Chaise, Thibaut; Nelias, Daniel; Robin, Vincent
2018-01-01
Surface treatment methods, such as shot peening or laser shock peening, are generally used to introduce superficial compressive residual stresses in mechanical parts. These processes are carried out during the manufacturing steps or for the purpose of repairing. The compressive residual stresses prevent the initiation and growth of cracks and thus improve the fatigue life of mechanical components. Electromagnetic pulse peening (EMP) is an innovative process that could be used to introduce compressive residual stresses in conductive materials. It acts by generating a high transient electromagnetic field near the working surface. In this paper, the EMP process is presented and a sequentially coupled electromagnetic and mechanical model is developed for its simulation. This 2D axisymmetric model is set up with the commercial finite element software SYSWELD. After description and validation, the numerical model is used to simulate a case of introducing residual stresses of compression in a nickel-based alloy 690 thick sample, by the means of electromagnetic pulses. The results are presented in terms of effective plastic strain and residual mean stress. The influence of the process parameters, such as current intensity and frequency, on the results is analyzed. Finally, the predictability of the process is shown by several correlation studies.
Electromagnetic pulses at the boundary of a nonlinear plasma
International Nuclear Information System (INIS)
Satorius, E.H.
1975-01-01
An investigation was made of the behavior of strong electromagnetic pulses at the boundary of a nonlinear, cold, collisionless, and uniform plasma. The nonlinearity considered here is due to the nonlinear terms in the fluid equation which is used to describe the plasma. Two cases are studied. First, the case where there is a voltage pulse applied across the plane boundary of a semi-infinite, nonlinear plasma. Two different voltage pulses are considered, i.e., a delta function pulse and a suddenly turned-on sinusoidal pulse. The resulting electromagnetic fields propagating in the nonlinear plasma are found in this case. In the second case, the reflection of incident E-polarized and H-polarized, electromagnetic pulses at various angles of incidence from a nonlinear, semi-infinite plasma are considered. Again, two forms of incident pulses are considered: a delta function pulse and a suddenly turned-on sinusoidal pulse. In case two, the reflected electromagnetic fields are found. In both cases, the method used for finding the fields is to first solve the fluid equation (which describes the plasma) for the nonlinear conduction current in terms of the electric field using a perturbation method (since the nonlinear effects are assumed to be small). Next, this current is substituted into Maxwell's equations, and finally the electromagnetic fields which satisfy the boundary conditions are found. (U.S.)
Interaction of the electromagnetic waves and non-magnetized plasmas
International Nuclear Information System (INIS)
Sun Aiping; Qiu Xiaoming; Dong Yuying; Li Liqiong
2002-01-01
The propagation of electromagnetic waves with 0.5 - 10 GHz in a non-magnetized collisional plasma slab is studied numerically. The change in the absorbed power, reflected power and transmitted power of the electromagnetic wave with collisional frequency of electrons and neutral atoms in plasma from 0.1 - 10 GHz, is calculated, in the condition of the uniform plasma with density of 10 10 or 10 11 cm -3 and depth of 10 cm, and the non-uniform plasma with density distribution of n = n 0 exp[2(z/d-1)] and depth of 10 cm, respectively. The results show that the absorbed power in either uniform or non-uniform plasma is large when the plasma density is large and collision frequency is high, and the peak value is 90%
Electromagnetic radiation by quark-gluon plasma in magnetic field
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...
The parametrized simulation of electromagnetic showers
International Nuclear Information System (INIS)
Peters, S.
1992-09-01
The simulation of electromagnetic showers in calorimeters by detailed tracking of all secondary particles is extremely computer time consuming. Without loosing considerably in precision, the use of parametrizations for global shower properties may reduce the computing time by factors of 10 1 to 10 4 , depending on the energy, the degree of parametrization, and the complexity in the material description and the cut off energies in the detailed simulation. To arrive at a high degree of universality, parametrizations of individual electromagnetic showers in homogeneous media are developed, taking the dependence of the shower development on the material into account. In sampling calorimeters, the inhomogeneous material distribution leads to additional effects which can be taken into account by geometry dependent terms in the parametrization of the longitudinal and radial energy density distributions. Comparisons with detailed simulations of homogeneous and sampling calorimeters show very good agreement in the fluctuations, correlations, and signal averages of spatial energy distributions. Verifications of the algorithms for the simulation of the H1 detector are performed using calorimeter test data for different moduls of the H1 liquid argon calorimeter. Special attention has been paid to electron pion separation, which is of great importance for physics analysis. (orig.) [de
Plasma theory and simulation research
International Nuclear Information System (INIS)
Birdsall, C.K.
1989-01-01
Our research group uses both theory and simulation as tools in order to increase the understanding of instabilities, heating, diffusion, transport and other phenomena in plasmas. We also work on the improvement of simulation, both theoretically and practically. Our focus has been more and more on the plasma edge (the ''sheath''), interactions with boundaries, leading to simulations of whole devices (someday a numerical tokamak)
Stimulated brillouin scattering of electromagnetic waves in a dusty plasma
International Nuclear Information System (INIS)
Salimullah, M.; Sen, A.
1991-08-01
The stimulated Brilluoin scattering of electromagnetic waves in a homogeneous, unmagnetized and collisionless dusty plasma has been investigated theoretically. The Vlasov equation has been solved perturbatively to find the nonlinear response of the plasma particles. The presence of the dust particles introduces a background inhomogeneous electric field which significantly influences the dispersive properties of the plasma. At the ion acoustic branch we find the usual scattering slightly modified by the charged dust grains. However, at the frequency lower than the ion acoustic branch we find a new mode of the plasma arising from the oscillations of the ions in the static structure of the dust distribution. This low frequency branch causes enhanced stimulated Brillouin scattering of electromagnetic waves in a dusty plasma. (author). 15 refs
PIC simulation of electron acceleration in an underdense plasma
Directory of Open Access Journals (Sweden)
S Darvish Molla
2011-06-01
Full Text Available One of the interesting Laser-Plasma phenomena, when the laser power is high and ultra intense, is the generation of large amplitude plasma waves (Wakefield and electron acceleration. An intense electromagnetic laser pulse can create plasma oscillations through the action of the nonlinear pondermotive force. electrons trapped in the wake can be accelerated to high energies, more than 1 TW. Of the wide variety of methods for generating a regular electric field in plasmas with strong laser radiation, the most attractive one at the present time is the scheme of the Laser Wake Field Accelerator (LWFA. In this method, a strong Langmuir wave is excited in the plasma. In such a wave, electrons are trapped and can acquire relativistic energies, accelerated to high energies. In this paper the PIC simulation of wakefield generation and electron acceleration in an underdense plasma with a short ultra intense laser pulse is discussed. 2D electromagnetic PIC code is written by FORTRAN 90, are developed, and the propagation of different electromagnetic waves in vacuum and plasma is shown. Next, the accuracy of implementation of 2D electromagnetic code is verified, making it relativistic and simulating the generating of wakefield and electron acceleration in an underdense plasma. It is shown that when a symmetric electromagnetic pulse passes through the plasma, the longitudinal field generated in plasma, at the back of the pulse, is weaker than the one due to an asymmetric electromagnetic pulse, and thus the electrons acquire less energy. About the asymmetric pulse, when front part of the pulse has smaller time rise than the back part of the pulse, a stronger wakefield generates, in plasma, at the back of the pulse, and consequently the electrons acquire more energy. In an inverse case, when the rise time of the back part of the pulse is bigger in comparison with that of the back part, a weaker wakefield generates and this leads to the fact that the electrons
Spontaneous electromagnetic emission from a strongly localized plasma flow.
Tejero, E M; Amatucci, W E; Ganguli, G; Cothran, C D; Crabtree, C; Thomas, E
2011-05-06
Laboratory observations of electromagnetic ion-cyclotron waves generated by a localized transverse dc electric field are reported. Experiments indicate that these waves result from a strong E×B flow inhomogeneity in a mildly collisional plasma with subcritical magnetic field-aligned current. The wave amplitude scales with the magnitude of the applied radial dc electric field. The electromagnetic signatures become stronger with increasing plasma β, and the radial extent of the power is larger than that of the electrostatic counterpart. Near-Earth space weather implications of the results are discussed.
Nonlinear dynamics of electromagnetic pulses in cold relativistic plasmas
Energy Technology Data Exchange (ETDEWEB)
Bonatto, A.; Pakter, R.; Rizzato, F.B. [Universidade Federal do Rio Grande do Sul, Instituto de Fisica, Rio Grande do Sul (Brazil)
2004-07-01
The propagation of intense electromagnetic pulses in plasmas is a subject of current interest particularly for particle acceleration and laser fusion.In the present analysis we study the self consistent propagation of nonlinear electromagnetic pulses in a one dimensional relativistic electron-ion plasma, from the perspective of nonlinear dynamics. We show how a series of Hamiltonian bifurcations give rise to the electric fields which are of relevance in the subject of particle acceleration. Connections between these bifurcated solutions and results of earlier analysis are made. (authors)
Plasma simulations on an unstructured grid
International Nuclear Information System (INIS)
Fritts, M.J.; Drobot, A.
1988-01-01
The accuracy of plasma simulations in complicated geometries often depends on the ability to properly resolve and describe boundary structures. The authors describe in this paper an approach for boundary conformal plasma simulations using triangular meshes in three dimensions. They constructed a code (BERMUDA) with arbitrary connectivity. The restriction imposed on the grid structure is that all of the triangles on the mesh have angles less than 90 0 . Under this restriction the triangular grid and the conjugate mesh have a simple relationship which permits the construction of simple and accurate algorithms. With BERMUDA they have implemented a number of solvers which include electrostatics, electromagnetics, hydrodynamics, and particle-in-cell simulations. The properties of the mesh structure and of algorithms for the various solvers are described. Results of simple calculations are presented
Collective scattering of electromagnetic waves from a relativistic magnetized plasma
International Nuclear Information System (INIS)
Lu Quankang
1998-01-01
Recently, laser and microwave scattering has become one of the important diagnostic means for plasma. Laser and microwave correlative scattering spectrum is determined by particle-density fluctuations in a weak turbulent plasma. In a relativistic plasma, on the basis of complete electromagnetic-interaction between particles, a general expression for particle density fluctuations and spectrums of laser and microwave scattering from a magnetized plasma are derived. The laser and microwave scattering spectrums provide informations on electron density and temperature, ion temperature, resonance and nonresonance effects. (author)
Force-free electromagnetic pulses in a laboratory plasma
Stenzel, R. L.; Urrutia, J. M.
1990-01-01
A short, intense current pulse is drawn from an electrode immersed in a magnetized afterglow plasma. The induced magnetic field B(r,t) assumes the shape of a helical double vortex which propagates along B(0) through the uniform plasma as a whistler mode. The observations support a prediction of force-free (J x B + neE = 0) electromagnetic fields and solitary waves. Energy and helicity are approximately conserved.
Certain relativistic effects due to strong electromagnetic fields in plasmas
International Nuclear Information System (INIS)
Tsintsadze, N.L.
1974-01-01
It is shown that the propagation of a strong electromagnetic wave in an electron plasma can lead to a generation of a constant electron current along the direction of propagation and to a large increase in the average electron density. (Auth.)
Electromagnetic fields produced by simulated spacecraft discharges
Nonevicz, J. E.; Adamo, R. C.; Beers, B. L.; Delmer, T. N.
1980-01-01
The initial phase of a broader, more complete program for the characterization of electrical breakdowns on spacecraft insulating materials is described which consisted of the development of a discharge simulator and characterization facility and the performance of a limited number of discharge measurements to verify the operation of the laboratory setup and to provide preliminary discharge transient field data. A preliminary model of the electromagnetic characteristics of the discharge was developed. It is based upon the "blow off" current model of discharges, with the underlying assumption of a propagating discharge. The laboratory test facility and discharge characterization instrumentation are discussed and the general results of the "quick look" tests are described on quartz solar reflectors aluminized Kapton and silver coated Teflon are described.
Stimulated Brillouin scattering of electromagnetic Alfven waves in a plasma
International Nuclear Information System (INIS)
Sharma, R.R.; Sharma, R.C.; Sharma, O.P.
1981-01-01
The phenomenon of stimulated Brillouin scattering of electromagnetic Alfven waves in a plasma is investigated by employing fluid model approach. The low frequency nonlinearity of ion acoustic wave arises through the ponderomotive force on ions and high frequency nonlinearity arises through the equation of continuity. For a typical isothermal plasma (Tsub(e)/Tsub(i)approx.=10), Alfven wave frequency ω 0 approx.=10 6 rad. sec -1 , the threshold for this instability in a uniform plasma is approx.= milliwatt cm -2 . Above the threshold, the growth rate for forward and back scatterings are approx.=10 -3 rad.sec -1 and approx.=10 -4 rad.sec. -1 , respectively. (author)
International Nuclear Information System (INIS)
Beck, A.
2008-11-01
The N-Body plasma simulation consists in calculating the Coulomb interaction between N charged particles. We adapted an N-Body 'tree code' algorithm, successfully used in the gravitational case, for the simulation of plasma. So far, we have found two main applications which suits this technique particularly well. First, the expansion of a plasma into vacuum. In this kind of simulations, densities of very different order of magnitude have to interact. Some areas can have an hydrodynamic behavior whereas some others are filled by energetic particles following ballistic trajectories. Problems which take into account plasma-vacuum interface are almost impossible to study with common simulation techniques ( Vlasov, Fokker-Planck). The other application consists in simulating moderately or strongly coupled plasma. It deals with many laboratory plasmas as well as astrophysical plasmas such as the convective zone of the sun. In coupled plasmas, close collisions between charges can not be neglected as it is done in most of the other simulation techniques. The N-Body technique allows the accurate description of the trajectory of each single particle and thus to take into account the strong deviations due to the close collisions. (author)
Electromagnetic wave propagation in relativistic magnetized plasmas
International Nuclear Information System (INIS)
Weiss, I.
1985-01-01
An improved mathematical technique and a new code for deriving the conductivity tensor for collisionless plasmas have been developed. The method is applicable to a very general case, including both hot (relativistic) and cold magnetized plasmas, with only isotropic equilibrium distributions being considered here. The usual derivation starts from the relativistic Vlasov equation and leads to an integration over an infinite sum of Bessel functions which has to be done numerically. In the new solution the integration is carried out over a product of two Bessel functions only. This reduces the computing time very significantly. An added advantage over existing codes is our capability to perform the computations for waves propagating obliquely to the magnetic field. Both improvements greatly facilitate investigations of properties of the plasma under conditions hitherto unexplored
The electromagnetic properties of plasma produced by hypervelocity impact
Zhang, Qingming; Gong, Liangfei; Ma, Yuefen; Long, Renrong; Gong, Zizheng
2018-02-01
The change of electron density in moving plasma in this paper is empirically determined according to multiple ground-based experimental results and the assumption of the Maxwell distribution. Moreover, the equation of the magnetic field intensity, dominated by the current due to the collective electron movement during the expansion, is presented on the basis of the Biot-Savart law, and its relationship with time and space is subsequently depicted. In addition, hypervelocity impact experiments on a 2AL12 target have been carried out using a two-stage light gas gun to accelerate a 2AL12 projectile of 6.4 mm to 6.2 km/s. Spiral coils are designed to measure the intensity of the electromagnetic field induced by this impact. The experimental results show that the magnetic field strength is an alternate pulse maintaining nearly 1 ms and its maximum is close to 15 μT, which is strong enough to interfere with the communication circuit and chip in spacecrafts. Lastly, numerical simulation of the magnetic field intensity using this experimental parameter reveals that the intensity in our estimation from our theory tends to be well consistent with the experimental data in the first peak of the pulse signal.
Scalable Simulation of Electromagnetic Hybrid Codes
International Nuclear Information System (INIS)
Perumalla, Kalyan S.; Fujimoto, Richard; Karimabadi, Dr. Homa
2006-01-01
New discrete-event formulations of physics simulation models are emerging that can outperform models based on traditional time-stepped techniques. Detailed simulation of the Earth's magnetosphere, for example, requires execution of sub-models that are at widely differing timescales. In contrast to time-stepped simulation which requires tightly coupled updates to entire system state at regular time intervals, the new discrete event simulation (DES) approaches help evolve the states of sub-models on relatively independent timescales. However, parallel execution of DES-based models raises challenges with respect to their scalability and performance. One of the key challenges is to improve the computation granularity to offset synchronization and communication overheads within and across processors. Our previous work was limited in scalability and runtime performance due to the parallelization challenges. Here we report on optimizations we performed on DES-based plasma simulation models to improve parallel performance. The net result is the capability to simulate hybrid particle-in-cell (PIC) models with over 2 billion ion particles using 512 processors on supercomputing platforms
Interaction of Electromagnetic Fields with Magnetized Plasmas
1994-03-31
collisions, the constancy of the mag- vermity, Sfax , Tunisia. netic moment makes it possible to obtain a relationship Phys. Fluds 8 1 (5), May 1969 0699-6221...Engineering. Technical Uni- where 6 is the field modulation factor and E, is the initial versify. Sfax . Tunisia. energy in electron-volts. The...in Sfax , of the original organizing committee which set up the Nuclear and Plasma Tunisia, on August 9, 1955. He received the B.S. Sciences Society
Proton moire fringes for diagnosing electromagnetic fields in opaque materials and plasmas
International Nuclear Information System (INIS)
Mackinnon, A.J.; Patel, P.K.; Price, D.W.; Hicks, D.; Romagnani, L.; Borghesi, M.
2003-01-01
High contrast proton moire fringes have been obtained in a laser-produced proton beam. Moire fringes with modulation of 20%-30% were observed in protons with energies in the range of 4-7 MeV. Monte Carlo simulations with simple test fields showed that shifts in the moire fringes can be used to give quantitative information on the strength of transient electromagnetic fields inside plasmas and materials that are opaque to conventional probing methods
Kinetic electrons in global electromagnetic gyrokinetic particle simulations
Nishimura, Y.; Wang, W.
2005-10-01
Employing an electromagnetic gyrokinetic simulation model,ootnotetextZ. Lin and L. Chen, Phys. Plasmas 8, 1447 (2001). kinetic electron dynamics in global tokamak geometry is investigated. The massless fluid electron model is developed as a base. We further evolve gyrokinetic equations for non-adiabatic kinetic electrons. To obtain the magnetic perturbation, the fluid-kinetic hybrid electron model^1 employs the inverse of the Faraday's law. Instead, the Ampere's law is used as a closure relation to avoid uncertainties in estimating ue|, the moment of the electron velocities. The physics goal is to investigate the finite beta effects on the turbulent transport, as well as α particle driven turbulence.ootnotetextI. Holod, Z. Lin, et al., this conference. This work is supported by Department of Energy (DOE) Cooperative Agreement No. DE-FC02-03ER54695 (UCI), DOE Contract No. DE-AC02-76CH03073 (PPPL).
Two dimensional plasma simulation code
International Nuclear Information System (INIS)
Hazak, G.; Boneh, Y.; Goshen, Sh.; Oreg, J.
1977-03-01
An electrostatic two-dimensional particle code for plasma simulation is described. Boundary conditions which take into account the finiteness of the system are presented. An analytic solution for the case of crossed fields plasma acceleration is derived. This solution serves as a check on a computer test run
International Nuclear Information System (INIS)
Yang Min; Li Xiaoping; Xie Kai; Liu Donglin; Liu Yanming
2013-01-01
A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a “black out” phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm× 260 mm× 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.
International Nuclear Information System (INIS)
Guo Bin
2009-01-01
Based on the electromagnetic theory and by using an analytical technique-the transfer matrix method, the obliquely incident electromagnetic waves propagating in one-dimension plasma photonic crystals is studied. The dispersion relations for both the P-polarization waves and S-polarization waves, depending on the plasma density, plasma thickness and period, are discussed. (basic plasma phenomena)
The effect of plasma drift on the electromagnetic cyclotron instability
International Nuclear Information System (INIS)
Kulkarni, V.H.; Rycroft, M.J.
1979-01-01
It is shown that the drift of plasma across a homogeneous magnetic field causes the generation of a wave electric field which, for waves propagating along the magnetic field in the whistler mode, is in the direction of the magnetic field. This leads to Landau damping of the wave field by the background electron distribution, simultaneously with amplification via the electromagnetic cyclotron instability. The drift velocity of the plasma for zero net growth of a whistler mode signal is calculated. It is suggested that such a process occurs in the equatorial region of the magnetosphere during a geomagnetic storm and accounts for the missing band of emissions at half the equatorial gyrofrequency. (Auth.)
Modelling, simulation and visualisation for electromagnetic non-destructive testing
International Nuclear Information System (INIS)
Ilham Mukriz Zainal Abidin; Abdul Razak Hamzah
2010-01-01
This paper reviews the state-of-the art and the recent development of modelling, simulation and visualization for eddy current Non-Destructive Testing (NDT) technique. Simulation and visualization has aid in the design and development of electromagnetic sensors and imaging techniques and systems for Electromagnetic Non-Destructive Testing (ENDT); feature extraction and inverse problems for Quantitative Non-Destructive Testing (QNDT). After reviewing the state-of-the art of electromagnetic modelling and simulation, case studies of Research and Development in eddy current NDT technique via magnetic field mapping and thermography for eddy current distribution are discussed. (author)
International Nuclear Information System (INIS)
Langdon, A.B.
1985-01-01
Implicit time integration methods have been used extensively in numerical modelling of slowly varying phenomena in systems that also support rapid variation. Examples include diffusion, hydrodynamics and reaction kinetics. This article discussed implementation of implicit time integration in plasma codes of the ''particle-in-cell'' family, and the benefits to be gained
Electromagnetic plasma models for microwave plasma cavity reactors
Frasch, L.; Asmussen, J.
1984-06-01
A procedure used to design cavity applicators that efficiently produce cylindrical and disk microwave discharges is reviewed. In contrast to most microwave applicators these cavities utilize single mode excitation of the plasma. This method of excitation has the advantage of providing efficient coupling (zero reflected power) to the plasma over a wide range of discharge loading conditions while also allowing, if desired, electric feedback control of the heating process. The design procedure is generalized to any lossy dielectric. Experimental and theoretical research required to further understand microwave discharges is also discussed.
Labotratory Simulation Experiments of Cometary Plasma
MINAMI, S.; Baum, P. J.; Kamin, G.; White, R. S.; 南, 繁行
1986-01-01
Laboratory simulation experiment to study the interaction between a cometary plasma and the solar wind has been performed using the UCR-T 1 space simulation facility at the Institute of Geophysics and Planetary Physics, the University of California, Riverside. Light emitting plasma composed of Sr, Ba and/or C simulating cometary coma plasma is produced by a plasma emitter which interacts with intense plasma flow produced by a co-axial plasma gun simulating the solar wind. The purpose of this ...
2-D electromagnetic simulation of passive microstrip circuits
Dueñas Jiménez, Alejandro
2009-01-01
A reference for circuit design engineers and microwave engineers. It uses a simple 2-D electromagnetic simulation procedure to provide basic knowledge and practical insight into quotidian problems of microstrip passive circuits applied to microwave systems and digital technologies.
Electro-Magnetic Fields and Plasma in the Cosmos
International Nuclear Information System (INIS)
Scott, Donald E.
2006-01-01
It is becoming widely recognized that a majority of baryons in the cosmos are in the plasma state. But, fundamental disagreements about the properties and behavior of electro-magnetic fields in these plasmas exist between the science of modern astronomy and the experimentally verified laws of electrical engineering and physics. Some astronomers claim that magnetic fields can be open-ended - that they begin on or beneath the Sun's surface and extend outward to infinity. Astrophysicists have claimed that galactic magnetic fields begin and end on molecular clouds. Electrical engineers, most physicists, and the pioneers in electromagnetic field theory disagree - magnetic fields have no beginning or end. Since these two viewpoints are mutually exclusive, both cannot be correct; one must be completely false. Many astrophysicists claim that magnetic fields are 'frozen into' electric plasma. We also examine the basis for this claim. It has been shown to be incorrect in the laboratory. The hypothetical 'magnetic merging' mechanism is also reviewed in light of both theoretical and experimental investigations. The cause of large-scale filamentation in the cosmos is also simply revealed by experimental results obtained in plasma laboratories
Interaction of High Intensity Electromagnetic Waves with Plasmas: Final Report
International Nuclear Information System (INIS)
Shvets, G.
2008-01-01
The focus of our work during the duration of this grant was on the following areas: (a) the fundamental plasma physics of intense laser-plasma interactions, including the nonlinear excitation of plasma waves for accelerator applications, as well as the recently discovered by us phenomenon of the relativistic bi-stability of relativistic plasma waves driven by a laser beatwave; (b) interaction of high power microwave beams with magnetized plasma, including some of the recently discovered by us phenomena such as the Undulator Induced Transparency (UIT) as well as the new approaches to dynamic manipulation of microwave pulses; (c) investigations of the multi-color laser pulse interactions in the plasma, including the recently discovered by us phenomenon of Electromagnetic Cascading (EC) and the effect of the EC of three-dimensional dynamics of laser pulses (enhanced/suppressed selffocusing etc.); (d) interaction of high-current electron beams with the ambient plasma in the context of Fast Ignitor (FI) physics, with the emphasis on the nonlinear dynamics of the Weibel instability and beam filamentation.
Magnetohydrodynamic Simulation of Capillary Plasmas
Bobrova, N. A.; Razinkova, T. L.; Sasorov, P. V.; Bulanov, S. V.; Farina, D.; Pozzoli, R.
1996-11-01
The dynamics of capillary plasmas relevant to regimes where amplification of soft x-rays has been observed [J. J. Rocca, et al. Phys. Rev. Lett., 73, 2192 (1994); Phys. Plasmas, 2 2547 (1995)] is investigated by means of a magnetohydrodynamic one-dimensional numerical simulation code which takes into account dissipative processes, ablation and ionization of the wall material. The dynamics of the discharge is found to be different from what could be inferred from standard plasma pinch physics, due to the role of the capillary wall ablation. The formation of a hot dense plasma kernel close to the channel axis, due to the presence of converging shock waves, is observed in the simulation. The main features of this process are found to be in good agreement with the experimental observations of the amplification of Ne-like Ar emission.
Simulation of plasma loading of high-pressure RF cavities
Energy Technology Data Exchange (ETDEWEB)
Yu, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Computational Science Initiative; Samulyak, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Computational Science Initiative; Stony Brook Univ., NY (United States). Dept. of Applied Mathematics and Statistics; Yonehara, K. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Freemire, B. [Northern Illinois Univ., DeKalb, IL (United States)
2018-01-11
Muon beam-induced plasma loading of radio-frequency (RF) cavities filled with high pressure hydrogen gas with 1% dry air dopant has been studied via numerical simulations. The electromagnetic code SPACE, that resolves relevant atomic physics processes, including ionization by the muon beam, electron attachment to dopant molecules, and electron-ion and ion-ion recombination, has been used. Simulations studies have also been performed in the range of parameters typical for practical muon cooling channels.
Simulation of plasma loading of high-pressure RF cavities
Yu, K.; Samulyak, R.; Yonehara, K.; Freemire, B.
2018-01-01
Muon beam-induced plasma loading of radio-frequency (RF) cavities filled with high pressure hydrogen gas with 1% dry air dopant has been studied via numerical simulations. The electromagnetic code SPACE, that resolves relevant atomic physics processes, including ionization by the muon beam, electron attachment to dopant molecules, and electron-ion and ion-ion recombination, has been used. Simulations studies have been performed in the range of parameters typical for practical muon cooling channels.
Simulation science for fusion plasmas
International Nuclear Information System (INIS)
Sudo, S; Skoric, M M; Watanabe, T-H; Todo, Y; Miura, H; Ishizaki, R; Ito, A; Ohtani, H; Ishiguro, S; Tomita, Y; Horiuchi, R; Ishizawa, A; Usami, S; Nakamura, H; Ito, Atsushi; Takayama, A; Sato, M; Yamamoto, T; Den, M; Sakagami, H
2008-01-01
The world fusion effort has embarked into a new age with the construction of ITER in Cadarache, France, which will be the first magnetic confinement fusion plasma experiment dominated by the self-heating of fusion reactions. In order to operate and control burning plasmas and next generation demo fusion reactors, an advanced capability for comprehensive integrated computer simulations that are fully verified and validated against experimental data will be necessary. The ultimate goal is to predict reliably the behaviour of plasmas in toroidal magnetic confinement devices on all relevant scales, both in time and space. In addition to developing a sophisticated integrated simulation codes, directed advanced research in fusion physics, applied mathematics, computer science and software is envisaged. In this paper we review the basic strategy and main research efforts at the Department of Simulation Science of the National Institute for Fusion Science (NIFS)- which is the Inter University Institute and the coordinating Center of Excellence for academic fusion research in Japan. We overview a simulation research at NIFS, in particular relation to experiments in the Large Helical Device (LHD), the world's largest superconducting heliotron device, as a National Users' facility (see Motojima et al.). Our main goal is understanding and systemizing the rich hierarchy of physical mechanisms in fusion plasmas, supported by exploring a basic science of complexity of plasma as a highly nonlinear, non-equilibrium, open system. The aim is to establish a simulation science as a new interdisciplinary field by fostering collaborative research in utilizing the large-scale supercomputer simulators. A concept of the hierarchy-renormalized simulation modelling will be invoked en route toward the LHD numerical test reactor.
International Nuclear Information System (INIS)
Shlapakovski, A. S.; Beilin, L.; Krasik, Ya. E.; Hadas, Y.; Schamiloglu, E.
2015-01-01
Nanosecond-scale evolution of plasma and RF electromagnetic fields during the release of energy from a microwave pulse compressor with a plasma interference switch was investigated numerically using the code MAGIC. The plasma was simulated in the scope of the gas conductivity model in MAGIC. The compressor embodied an S-band cavity and H-plane waveguide tee with a shorted side arm filled with pressurized gas. In a simplified approach, the gas discharge was initiated by setting an external ionization rate in a layer crossing the side arm waveguide in the location of the electric field antinode. It was found that with increasing ionization rate, the microwave energy absorbed by the plasma in the first few nanoseconds increases, but the absorption for the whole duration of energy release, on the contrary, decreases. In a hybrid approach modeling laser ignition of the discharge, seed electrons were set around the electric field antinode. In this case, the plasma extends along the field forming a filament and the plasma density increases up to the level at which the electric field within the plasma decreases due to the skin effect. Then, the avalanche rate decreases but the density still rises until the microwave energy release begins and the electric field becomes insufficient to support the avalanche process. The extraction of the microwave pulse limits its own power by terminating the rise of the plasma density and filament length. For efficient extraction, a sufficiently long filament of dense plasma must have sufficient time to be formed
Shlapakovski, A. S.; Beilin, L.; Hadas, Y.; Schamiloglu, E.; Krasik, Ya. E.
2015-07-01
Nanosecond-scale evolution of plasma and RF electromagnetic fields during the release of energy from a microwave pulse compressor with a plasma interference switch was investigated numerically using the code MAGIC. The plasma was simulated in the scope of the gas conductivity model in MAGIC. The compressor embodied an S-band cavity and H-plane waveguide tee with a shorted side arm filled with pressurized gas. In a simplified approach, the gas discharge was initiated by setting an external ionization rate in a layer crossing the side arm waveguide in the location of the electric field antinode. It was found that with increasing ionization rate, the microwave energy absorbed by the plasma in the first few nanoseconds increases, but the absorption for the whole duration of energy release, on the contrary, decreases. In a hybrid approach modeling laser ignition of the discharge, seed electrons were set around the electric field antinode. In this case, the plasma extends along the field forming a filament and the plasma density increases up to the level at which the electric field within the plasma decreases due to the skin effect. Then, the avalanche rate decreases but the density still rises until the microwave energy release begins and the electric field becomes insufficient to support the avalanche process. The extraction of the microwave pulse limits its own power by terminating the rise of the plasma density and filament length. For efficient extraction, a sufficiently long filament of dense plasma must have sufficient time to be formed.
Magnetosheath plasma expansion: Hybrid simulations
Czech Academy of Sciences Publication Activity Database
Trávníček, Pavel; Hellinger, Petr; Taylor, M. G. G. T.; Escoubet, C. P.; Dandouras, I.; Lucek, E.
2007-01-01
Roč. 34, č. 15 (2007), L15104/1-L15104/5 ISSN 0094-8276 R&D Projects: GA ČR GA205/05/1011; GA AV ČR IAA300420602 Institutional research plan: CEZ:AV0Z30420517 Keywords : numerical simulations * marginal stability * mirror instability * proton cyclotron instability * hybrid simulations Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.744, year: 2007
Babitski, V. S.; Callegari, Th.; Simonchik, L. V.; Sokoloff, J.; Usachonak, M. S.
2017-08-01
The ability to use plasma columns of pulse discharges in argon at atmospheric pressure to form a one-dimensional electromagnetic band gap structure (or electromagnetic crystal) in the X-band waveguide is demonstrated. We show that a plasma electromagnetic crystal attenuates a microwave propagation in the stopband more than by 4 orders of magnitude. In order to obtain an effective control of the transmission spectrum comparable with a metallic regular structure, the electron concentration in plasma inhomogeneities should vary within the range from 1014 cm-3 to 1016 cm-3, while gas temperature and mean electron energy must be in the range of 2000 K and 0.5 eV, respectively, to lower electron collision frequency around 1010 s-1. We analyze in detail the time evolution response of the electromagnetic crystal according to the plasma parameters for the duration of the discharge. The interest of using atmospheric pressure discharges is to increase the microwave breakdown threshold in discharge volumes, whereby it becomes possible to perform dynamic control of high power microwaves.
Yang, Shengpeng; Zhou, Qing; Tang, Changjian; Chen, Shaoyong
2017-12-01
This particle-in-cell simulation study finds that the system of a long relativistic electron beam passing through an overdense plasma can produce high harmonic terahertz electromagnetic radiation. In this process, the electron beam is self-modulated to create a periodic electromagnetic structure which will resonate with the plasma wakefield and excite the electromagnetic instability in the nonlinear stage of the self-modulation. The study also finds that when the radiation is achieved, the self-modulated electron beam will be destroyed due to the self-consistent interaction among the radiation, the electron beam, and the plasma. Meanwhile, the radiation will gradually attenuate, which also coincides with the physical explanation of the radiation.
Electromagnetic radiation and nonlinear energy flow in an electron beam-plasma system
Whelan, D. A.; Stenzel, R. L.
1985-01-01
It is shown that the unstable electron-plasma waves of a beam-plasma system can generate electromagnetic radiation in a uniform plasma. The generation mechanism is a scattering of the unstable electron plasma waves off ion-acoustic waves, producing electromagnetic waves whose frequency is near the local plasma frequency. The wave vector and frequency matching conditions of the three-wave mode coupling are experimentally verified. The electromagnetic radiation is observed to be polarized with the electric field parallel to the beam direction, and its source region is shown to be localized to the unstable plasma wave region. The frequency spectrum shows negligible intensity near the second harmonic of the plasma frequency. These results suggest that the observed electromagnetic radiation of type III solar bursts may be generated near the local plasma frequency and observed downstream where the wave frequency is near the harmonic of the plasma frequency.
A framework for simulation and inversion in electromagnetics
Heagy, Lindsey J.; Cockett, Rowan; Kang, Seogi; Rosenkjaer, Gudni K.; Oldenburg, Douglas W.
2017-10-01
Simulations and inversions of electromagnetic geophysical data are paramount for discerning meaningful information about the subsurface from these data. Depending on the nature of the source electromagnetic experiments may be classified as time-domain or frequency-domain. Multiple heterogeneous and sometimes anisotropic physical properties, including electrical conductivity and magnetic permeability, may need be considered in a simulation. Depending on what one wants to accomplish in an inversion, the parameters which one inverts for may be a voxel-based description of the earth or some parametric representation that must be mapped onto a simulation mesh. Each of these permutations of the electromagnetic problem has implications in a numerical implementation of the forward simulation as well as in the computation of the sensitivities, which are required when considering gradient-based inversions. This paper proposes a framework for organizing and implementing electromagnetic simulations and gradient-based inversions in a modular, extensible fashion. We take an object-oriented approach for defining and organizing each of the necessary elements in an electromagnetic simulation, including: the physical properties, sources, formulation of the discrete problem to be solved, the resulting fields and fluxes, and receivers used to sample to the electromagnetic responses. A corresponding implementation is provided as part of the open source simulation and parameter estimation project SIMPEG (http://simpeg.xyz). The application of the framework is demonstrated through two synthetic examples and one field example. The first example shows the application of the common framework for 1D time domain and frequency domain inversions. The second is a field example that demonstrates a 1D inversion of electromagnetic data collected over the Bookpurnong Irrigation District in Australia. The final example is a 3D example which shows how the modular implementation is used to compute the
Electromagnetic radiation trapped in the magnetosphere above the plasma frequency
Gurnett, D. A.; Shaw, R. R.
1973-01-01
An electromagnetic noise band is frequently observed in the outer magnetosphere by the Imp 6 spacecraft at frequencies from about 5 to 20 kHz. This noise band generally extends throughout the region from near the plasmapause boundary to near the magnetopause boundary. The noise typically has a broadband field strength of about 5 microvolts/meter. The noise band often has a sharp lower cutoff frequency at about 5 to 10 kHz, and this cutoff has been identified as the local electron plasma frequency. Since the plasma frequency in the plasmasphere and solar wind is usually above 20 kHz, it is concluded that this noise must be trapped in the low-density region between the plasmapause and magnetopause boundaries. The noise bands often contain a harmonic frequency structure which suggests that the radiation is associated with harmonics of the electron cyclotron frequency.
Electromagnetic pulses produced by expanding laser-produced Au plasma
Czech Academy of Sciences Publication Activity Database
De Marco, Massimo; Cikhardt, J.; Krása, Josef; Velyhan, Andriy; Pfeifer, Miroslav; Krouský, Eduard; Klír, D.; Řezáč, K.; Limpouch, J.; Margarone, Daniele; Ullschmied, Jiří
2015-01-01
Roč. 60, č. 2 (2015), s. 239-243 ISSN 0029-5922 R&D Projects: GA MŠk EE2.3.20.0279; GA ČR GAP205/12/0454; GA MŠk(CZ) LD14089; GA MŠk LM2010014 Grant - others:LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : laser-produced plasma * electromagnetic pulse (EMP) * return target current * Moebius loop antenna * inductive target probe Subject RIV: BL - Plasma and Gas Discharge Physics; BH - Optics, Masers, Lasers (UFP-V) Impact factor: 0.546, year: 2015
Simulation of the Electromagnetic Properties of a Pestov Spark Counter
Pestov, Yu N; CERN. Geneva; Schmidt, H R; Thoma, P
1997-01-01
Both the electrostatic and the electromagnetic properties of the proposed Pestov Spark counter for the CERN-LHC experiment ALICE were calculated employing the HF simulation package MAFIA. The simulations helped to design a frontend readout board of high bandwidth for the transmission of the very fast signal induced by the spark to the frontend electronics.
Thermal insulation and confinement of plasma with a high-frequency electromagnetic field
International Nuclear Information System (INIS)
Vedenov, A.A.; Volkov, T.F.; Rudakov, L.I.; Sagdeyev, R.Z.; Glagolev, V.M.; Yeliseyev, G.A.; Khilil, V.V.
1958-01-01
At the Institute of Atomic Energy (Academy of Sciences, USSR) the problem of creating and thermally insulating plasma by means of high-frequency electromagnetic fields has been studied. Electromagnetic alternating fields which do not penetrate into plasma set up a pressure difference on the plasma boundary. There may be various ways of exciting alternating fields. One of the ways, most convenient from the radio engineering standpoint, is the setting up of a standing electromagnetic wave in a volume resonator partly filled with plasma. Such electromagnetic oscillations can be excited between the conductive walls of the resonator and the surface of plasma in such a way that the electromagnetic pressure, averaged over the high-frequency oscillations, with geometry specially selected, is the same at every point of the plasma surface
Electromagnetic Radiation in the Plasma Environment Around the Shuttle
Vayner, Boris V.; Ferguson, Dale C.
1995-01-01
As part of the SAMPIE (The Solar Array Module Plasma Interaction Experiment) program, the Langmuir probe (LP) was employed to measure plasma characteristics during the flight STS-62. The whole set of data could be divided into two parts: (1) low frequency sweeps to determine voltage-current characteristics and to find electron temperature and number density; (2) high frequency turbulence (HFT dwells) data caused by electromagnetic noise around the shuttle. The broadband noise was observed at frequencies 250-20,000 Hz. Measurements were performed in ram conditions; thus, it seems reasonable to believe that the influence of spacecraft operations on plasma parameters was minimized. The average spectrum of fluctuations is in agreement with theoretical predictions. According to purposes of SAMPIE, the samples of solar cells were placed in the cargo bay of the shuttle, and high negative bias voltages were applied to them to initiate arcing between these cells and surrounding plasma. The arcing onset was registered by special counters, and data were obtained that included the amplitudes of current, duration of each arc, and the number of arcs per one experiment. The LP data were analyzed for two different situations: with arcing and without arcing. Electrostatic noise spectra for both situations and theoretical explanation of the observed features are presented in this report.
Generation of electromagnetic pulses from plasma channels induced by femtosecond light strings
Cheng, Chung-Chieh; Wright, E. M.; Moloney, J. V.
2000-01-01
We present a model that elucidates the physics underlying the generation of an electromagnetic pulse from a femtosecond laser induced plasma channel. The radiation pressure force from the laser pulse spatially separates the ionized electrons from the heavier ions and the induced dipole moment subsequently oscillates at the plasma frequency and radiates an electromagnetic pulse.
Computer simulation of bounded plasmas
International Nuclear Information System (INIS)
Lawson, W.S.
1987-01-01
The problems of simulating a one-dimensional bounded plasma system using particles in a gridded space are systematically explored and solutions to them are given. Such problems include the injection of particles at the boundaries, the solution of Poisson's equation, and the inclusion of an external circuit between the confining boundaries. A recently discovered artificial cooling effect is explained as being a side-effect of quiet injection, and its potential for causing serious but subtle errors in bounded simulation is noted. The methods described in the first part of the thesis are then applied to the simulation of an extension of the Pierce diode problem, specifically a Pierce diode modified by an external circuit between the electrodes. The results of these simulations agree to high accuracy with theory when a theory exists, and also show some interesting chaotic behavior in certain parameter regimes. The chaotic behavior is described in detail
The inverse problem for the refractometry diagnostics of electromagnetic turbulence in plasma
International Nuclear Information System (INIS)
Lazarian, A.
1994-01-01
Turbulence is an important property of laboratory plasmas. A number of relevant diagnostics are based on the interaction of an electromagnetic beam with plasma. Here we discuss a refractometry technique, where information on plasma properties is obtained by probing plasma with a plane polarized electromagnetic beam. It is shown that the problem of recovering statistical properties of plasma turbulence from the line integrated data can be solved uniquely using a realistic model of plasma. Analytical expressions relating statistics of both the random density and random magnetic fields to the measured statistics have been found. This information is of importance in studies of plasma turbulence. (author)
Simulation of Heat Transfer and Electromagnetic Fields of Protected Microcomputers
Directory of Open Access Journals (Sweden)
Josef Lakatos
2006-01-01
Full Text Available The paper presents results of collaboration between Department of mechatronics and electronics at University of Žilina and VÚVT Engineering a.s. Žilina in area of heat transfer simulations and disturbing electromagnetic radiation simulations in computer construction. The simulations results were used in development of protected microcomputer prototypes in frame of applied research at both of workplaces.
Directory of Open Access Journals (Sweden)
Benjamin M. Cowan
2013-04-01
Full Text Available We describe a modification to the finite-difference time-domain algorithm for electromagnetics on a Cartesian grid which eliminates numerical dispersion error in vacuum for waves propagating along a grid axis. We provide details of the algorithm, which generalizes previous work by allowing 3D operation with a wide choice of aspect ratio, and give conditions to eliminate dispersive errors along one or more of the coordinate axes. We discuss the algorithm in the context of laser-plasma acceleration simulation, showing significant reduction—up to a factor of 280, at a plasma density of 10^{23} m^{-3}—of the dispersion error of a linear laser pulse in a plasma channel. We then compare the new algorithm with the standard electromagnetic update for laser-plasma accelerator stage simulations, demonstrating that by controlling numerical dispersion, the new algorithm allows more accurate simulation than is otherwise obtained. We also show that the algorithm can be used to overcome the critical but difficult challenge of consistent initialization of a relativistic particle beam and its fields in an accelerator simulation.
Development and Test of 2.5-Dimensional Electromagnetic PIC Simulation Code
Directory of Open Access Journals (Sweden)
Sang-Yun Lee
2015-03-01
Full Text Available We have developed a 2.5-dimensional electromagnetic particle simulation code using the particle-in-cell (PIC method to investigate electromagnetic phenomena that occur in space plasmas. Our code is based on the leap-frog method and the centered difference method for integration and differentiation of the governing equations. We adopted the relativistic Buneman-Boris method to solve the Lorentz force equation and the Esirkepov method to calculate the current density while maintaining charge conservation. Using the developed code, we performed test simulations for electron two-stream instability and electron temperature anisotropy induced instability with the same initial parameters as used in previously reported studies. The test simulation results are almost identical with those of the previous papers.
Electromagnetic ion cyclotron waves observed in the plasma depletion layer
Anderson, B. J.; Fuselier, S. A.; Murr, D.
1991-01-01
Observations from AMPTE/CCE in the earth's magnetosheath on October 5, 1984 are presented to illustrate 0.1 - 4.0 Hz magnetic field pulsations in the subsolar plasma depletion layer (PDL) for northward sheath field during a magnetospheric compression. The PDL is unambiguously identified by comparing CCE data with data from IRM in the upstream solar wind. Pulsations in the PDL are dominated by transverse waves with F/F(H+) 1.0 or less and a slot in spectral power at F/F(H+) = 0.5. The upper branch is left hand polarized while the lower branch is linearly polarized. In the sheath the proton temperature anisotropy is about 0.6 but it is about 1.7 in the PDL during wave occurrence. The properties and correlation of waves with increased anisotropy indicate that they are electromagnetic ion cyclotron waves.
QUICKSILVER - A general tool for electromagnetic PIC simulation
International Nuclear Information System (INIS)
Seidel, David B.; Coats, Rebecca S.; Johnson, William A.; Kiefer, Mark L.; Mix, L. Paul; Pasik, Michael F.; Pointon, Timothy D.; Quintenz, Jeffrey P.; Riley, Douglas J.; Turner, C. David
1997-01-01
The dramatic increase in computational capability that has occurred over the last ten years has allowed fully electromagnetic simulations of large, complex, three-dimensional systems to move progressively from impractical, to expensive, and recently, to routine and widespread. This is particularly true for systems that require the motion of free charge to be self-consistently treated. The QUICKSILVER electromagnetic Particle-In-Cell (EM-PIC) code has been developed at Sandia National Laboratories to provide a general tool to simulate a wide variety of such systems. This tool has found widespread use for many diverse applications, including high-current electron and ion diodes, magnetically insulated power transmission systems, high-power microwave oscillators, high-frequency digital and analog integrated circuit packages, microwave integrated circuit components, antenna systems, radar cross-section applications, and electromagnetic interaction with biological material. This paper will give a brief overview of QUICKSILVER and provide some thoughts on its future development
Electromagnetic Simulation Seminar and Opera/Tosca update Seminar
IT Department
2012-01-01
9 May 2012 Kjell Johnsen Auditorium – Room 30-7-018 Electromagnetic Simulation Seminar & Opera/Tosca update Seminar By Cobham Technical Services – Vector Fields Software Virtual prototyping using electromagnetic simulation software plays an important role in the design stage of many devices and the Opera software has been in use for this purpose at CERN for over a decade. A technical seminar will take place concerning the latest developments in electromagnetic design, analysis and multi-physics applications for large scientific experiments. Information will be presented on applications such as superconducting magnets and ion-beam sources. The seminar will be presented by engineers/physicists from Cobham Technical Services – Vector Fields Software who develop the Opera program. It is FREE to attend and is open to both current Opera software users and also those who wish to expand their knowledge and understand better the capabilities on offer. Prog...
FDTD simulation for plasma photonic crystals
International Nuclear Information System (INIS)
Liu Shaobin; Zhu Chuanxi; Yuan Naichang
2005-01-01
Plasma photonic crystals are artificially periodic structures, which are composed of plasmas and dielectric structures (or vacuum). In this paper, the piecewise linear current density recursive convolution (PLCDRC) finite-difference time-domain (FDTD) method is applied to study the plasma photonic crystals and those containing defects. In time-domain, the electromagnetic (EM) propagation process and reflection/transmission electric field of Gauss pulses passing through the plasma photonic crystals are investigated. In frequency-domain, the reflection and transmission coefficients of the pulses through the two kinds of crystals are computed. The results illustrate that the plasma photonic crystals mostly reflect for the EM wave of frequencies less than the plasma frequency, and mostly transmit for EM wave of frequencies higher than the plasma frequency. In high frequency domain, the plasma photonic crystals have photonic band gaps, which is analogous to the conventional photonic crystals. (authors)
Bowen, LI; Zhibin, WANG; Qiuyue, NIE; Xiaogang, WANG; Fanrong, KONG; Zhenyu, WANG
2018-01-01
Intensive collisions between electrons and neutral particles in partially ionized plasmas generated in atmospheric/sub-atmospheric pressure environments can sufficiently affect the propagation characteristics of electromagnetic waves, particularly in the sub-wavelength regime. To investigate the collisional effect in such plasmas, we introduce a simplified plasma slab model with a thickness on the order of the wavelength of the incident electromagnetic wave. The scattering matrix method (SMM) is applied to solve the wave equation in the plasma slab with significant nonuniformity. Results show that the collisions between the electrons and the neutral particles, as well as the incident angle and the plasma thickness, can disturb the transmission and reduce reflection significantly.
Simulating Sources of Superstorm Plasmas
Fok, Mei-Ching
2008-01-01
We evaluated the contributions to magnetospheric pressure (ring current) of the solar wind, polar wind, auroral wind, and plasmaspheric wind, with the surprising result that the main phase pressure is dominated by plasmaspheric protons. We used global simulation fields from the LFM single fluid ideal MHD model. We embedded the Comprehensive Ring Current Model within it, driven by the LFM transpolar potential, and supplied with plasmas at its boundary including solar wind protons, polar wind protons, auroral wind O+, and plasmaspheric protons. We included auroral outflows and acceleration driven by the LFM ionospheric boundary condition, including parallel ion acceleration driven by upward currents. Our plasmasphere model runs within the CRCM and is driven by it. Ionospheric sources were treated using our Global Ion Kinetics code based on full equations of motion. This treatment neglects inertial loading and pressure exerted by the ionospheric plasmas, and will be superceded by multifluid simulations that include those effects. However, these simulations provide new insights into the respective role of ionospheric sources in storm-time magnetospheric dynamics.
Presheath profiles in simulated tokamak edge plasmas
International Nuclear Information System (INIS)
LaBombard, B.; Conn, R.W.; Hirooka, Y.; Lehmer, R.; Leung, W.K.; Nygren, R.E.; Ra, Y.; Tynan, G.
1988-04-01
The PISCES plasma surface interaction facility at UCLA generates plasmas with characteristics similar to those found in the edge plasmas of tokamaks. Steady state magnetized plasmas produced by this device are used to study plasma-wall interaction phenomena which are relevant to tokamak devices. We report here progress on some detailed investigations of the presheath region that extends from a wall surface into these /open quotes/simulated tokamak/close quotes/ edge plasma discharges along magnetic field lines
The numerical simulation of plasma flow in cylindrical resonant cavity of microwave plasma thruster
International Nuclear Information System (INIS)
Tang, J.-L.; He, H.-Q; Mao, G.-W.
2004-01-01
Microwave Plasma Thruster (MPT) is an electro-thermal propulsive device. MPT consists of microwave generator, gas storing and supplying system, resonant cavity and accelerative nozzle. It generates free-floating plasma brought by the microwave discharge breakdown gas in the resonant cavity, and the plasma exhausted from nozzle produces thrust. MPT has prospective application in spacecraft because of its advantages of high thrust, moderate specific impulse and high efficiency. In this paper, the numerical simulation of the coupling flow field of microwave plasma in resonant cavity under different frequencies will be discussed. The results of numerical simulation are as follows: 1) When the resonant model TM 011 was used, the higher the microwave frequency was, the smaller the size of MPT. The distribution of the electromagnetic field in small cavity, however, remain unchanged. 2) When the resonant model was used, the distribution of the temperature, the pressure and the electronic density in the resonant cavity remained unchanged under different resonant frequencies. 3) When the resonant frequency was increased with a fixed pressure distribution in a small cavity, compare to the MPT with lower frequency, the gas flow rate, the microwave power and the nozzle throat diameter of MPT all decreased. 4) The electromagnetic field in the cylindrical resonant cavity for all MPT with different frequencies was disturbed by the plasma formation. The strong disturbance happened in the region close to the plasma. (author)
Gyrokinetic simulation of finite-β plasmas on parallel architectures
International Nuclear Information System (INIS)
Reynders, J.V.W.
1993-01-01
Much research exists on the linear and non-linear properties of plasma microinstabilities induced by density and temperature gradients. There has been an interest in the electromagnetic or finite-β effects on these microinstabilities. This thesis focuses on the finite-β modification of an ion temperature gradient (ITG) driven microinstability in a two-dimensional shearless and sheared-slab geometries. A gyrokinetic model is employed in the numerical and analytic studies of this instability. Chapter 1 introduces the electromagnetic gyrokinetic model employed in the numerical and analytic studies of the ITG instability. Some discussion of the Klimontovich particle representation of the gyrokinetic Vlasov equation and a multiple scale model of the background plasma gradient is presented. Chapter 2 details the computational issues facing an electromagnetic gyrokinetic particle simulation of the ITG mode. An electromagnetic extension of the partially linearized algorithm is presented with a comparison of quiet particle initialization routines. Chapter 3 presents and compares algorithms for the gyrokinetic particle simulation technique on SIMD and MIMD computing platforms. Chapter 4 discusses electromagnetic gyrokinetic fluctuation theory and provides a comparison of analytic and numerical results. Chapter 5 contains a linear and a non-linear three-wave coupling analysis of the finite-β modified ITG mode in a shearless slab geometry. Comparisons are made with linear and partially linearized gyrokinetic simulation results. Chapter 6 presents results from a finite-β modified ITG mode in a sheared slab geometry. The linear dispersion relation is derived and results from an integral eigenvalue code are presented. Comparisons are made with the gyrokinetic particle code in a variety of limits with both adiabatic and non-adiabatic electrons. Evidence of ITG driven microtearing is presented
Electromagnetic trajectory simulation using triaxial cage
Modi, Ankita; Kazi, Faruk
2018-02-01
This paper implements an open-loop controller for generating earth's magnetic field in vessel's co-ordinate frame. It also incorporates the rotational movements along the three axes, without physically moving the object. This has potential application in prediction of signature for ferromagnetic marine vessels in changing earth's magnetic field experienced by the vessel due to change in location. It also considers the effect of roll, pitch and heading changes. Uniform magnetic field simulator is designed to generate the required magnetic field in the vessel's coordinate frame. Simulation results are verified using experimental laboratory setup.
Directory of Open Access Journals (Sweden)
V. Pohjola
2010-03-01
Full Text Available We have developed a fully kinetic electromagnetic model to study instabilities and waves in planetary plasma environments. In the particle-in-a-cell (PIC model both ions and electrons are modeled as particles. An important feature of the developed global kinetic model, called HYB-em, compared to other electromagnetic codes is that it is built up on an earlier quasi-neutral hybrid simulation platform called HYB and that it can be used in conjunction with earlier hybrid models. The HYB models have been used during the past ten years to study globally the flowing plasma interaction with various Solar System objects: Mercury, Venus, the Moon, Mars, Saturnian moon Titan and asteroids. The new stand-alone fully kinetic model enables us to (1 study the stability of various planetary plasma regions in three-dimensional space, (2 analyze the propagation of waves in a plasma environment derived from the other global HYB models. All particle processes in a multi-ion plasma which are implemented on the HYB platform (e.g. ion-neutral-collisions, chemical processes, particle loss and production processes are also automatically included in HYB-em model.
In this brief report we study the developed approach by analyzing the propagation of high frequency electromagnetic waves in non-magnetized plasma in two cases: We study (1 expansion of a spherical wave generated from a point source and (2 propagation of a plane wave in plasma. The analysis shows that the HYB-em model is capable of describing these space plasma situations successfully. The analysis also suggests the potential of the developed model to study both high density-high magnetic field plasma environments, such as Mercury, and low density-low magnetic field plasma environments, such as Venus and Mars.
Directory of Open Access Journals (Sweden)
V. Pohjola
2010-03-01
Full Text Available We have developed a fully kinetic electromagnetic model to study instabilities and waves in planetary plasma environments. In the particle-in-a-cell (PIC model both ions and electrons are modeled as particles. An important feature of the developed global kinetic model, called HYB-em, compared to other electromagnetic codes is that it is built up on an earlier quasi-neutral hybrid simulation platform called HYB and that it can be used in conjunction with earlier hybrid models. The HYB models have been used during the past ten years to study globally the flowing plasma interaction with various Solar System objects: Mercury, Venus, the Moon, Mars, Saturnian moon Titan and asteroids. The new stand-alone fully kinetic model enables us to (1 study the stability of various planetary plasma regions in three-dimensional space, (2 analyze the propagation of waves in a plasma environment derived from the other global HYB models. All particle processes in a multi-ion plasma which are implemented on the HYB platform (e.g. ion-neutral-collisions, chemical processes, particle loss and production processes are also automatically included in HYB-em model. In this brief report we study the developed approach by analyzing the propagation of high frequency electromagnetic waves in non-magnetized plasma in two cases: We study (1 expansion of a spherical wave generated from a point source and (2 propagation of a plane wave in plasma. The analysis shows that the HYB-em model is capable of describing these space plasma situations successfully. The analysis also suggests the potential of the developed model to study both high density-high magnetic field plasma environments, such as Mercury, and low density-low magnetic field plasma environments, such as Venus and Mars.
A multiscale quantum mechanics/electromagnetics method for device simulations.
Yam, ChiYung; Meng, Lingyi; Zhang, Yu; Chen, GuanHua
2015-04-07
Multiscale modeling has become a popular tool for research applying to different areas including materials science, microelectronics, biology, chemistry, etc. In this tutorial review, we describe a newly developed multiscale computational method, incorporating quantum mechanics into electronic device modeling with the electromagnetic environment included through classical electrodynamics. In the quantum mechanics/electromagnetics (QM/EM) method, the regions of the system where active electron scattering processes take place are treated quantum mechanically, while the surroundings are described by Maxwell's equations and a semiclassical drift-diffusion model. The QM model and the EM model are solved, respectively, in different regions of the system in a self-consistent manner. Potential distributions and current densities at the interface between QM and EM regions are employed as the boundary conditions for the quantum mechanical and electromagnetic simulations, respectively. The method is illustrated in the simulation of several realistic systems. In the case of junctionless field-effect transistors, transfer characteristics are obtained and a good agreement between experiments and simulations is achieved. Optical properties of a tandem photovoltaic cell are studied and the simulations demonstrate that multiple QM regions are coupled through the classical EM model. Finally, the study of a carbon nanotube-based molecular device shows the accuracy and efficiency of the QM/EM method.
The INAF/IAPS Plasma Chamber for ionospheric simulation experiment
Diego, Piero
2016-04-01
The plasma chamber is particularly suitable to perform studies for the following applications: - plasma compatibility and functional tests on payloads envisioned to operate in the ionosphere (e.g. sensors onboard satellites, exposed to the external plasma environment); - calibration/testing of plasma diagnostic sensors; - characterization and compatibility tests on components for space applications (e.g. optical elements, harness, satellite paints, photo-voltaic cells, etc.); - experiments on satellite charging in a space plasma environment; - tests on active experiments which use ion, electron or plasma sources (ion thrusters, hollow cathodes, field effect emitters, plasma contactors, etc.); - possible studies relevant to fundamental space plasma physics. The facility consists of a large volume vacuum tank (a cylinder of length 4.5 m and diameter 1.7 m) equipped with a Kaufman type plasma source, operating with Argon gas, capable to generate a plasma beam with parameters (i.e. density and electron temperature) close to the values encountered in the ionosphere at F layer altitudes. The plasma beam (A+ ions and electrons) is accelerated into the chamber at a velocity that reproduces the relative motion between an orbiting satellite and the ionosphere (≈ 8 km/s). This feature, in particular, allows laboratory simulations of the actual compression and depletion phenomena which take place in the ram and wake regions around satellites moving through the ionosphere. The reproduced plasma environment is monitored using Langmuir Probes (LP) and Retarding Potential Analyzers (RPA). These sensors can be automatically moved within the experimental space using a sled mechanism. Such a feature allows the acquisition of the plasma parameters all around the space payload installed into the chamber for testing. The facility is currently in use to test the payloads of CSES satellite (Chinese Seismic Electromagnetic Satellite) devoted to plasma parameters and electric field
Electromagnetic simulation using the FDTD method
Sullivan, Dennis M
2013-01-01
A straightforward, easy-to-read introduction to the finite-difference time-domain (FDTD) method Finite-difference time-domain (FDTD) is one of the primary computational electrodynamics modeling techniques available. Since it is a time-domain method, FDTD solutions can cover a wide frequency range with a single simulation run and treat nonlinear material properties in a natural way. Written in a tutorial fashion, starting with the simplest programs and guiding the reader up from one-dimensional to the more complex, three-dimensional programs, this book provides a simple, yet comp
Ionospheric electron acceleration by electromagnetic waves near regions of plasma resonances
International Nuclear Information System (INIS)
Villalon, E.
1989-01-01
Electron acceleration by electromagnetic fields propagating in the inhomogeneous ionospheric plasma is investigated. It is found that high-amplitude short wavelength electrostatic waves are generated by the incident electromagnetic fields that penetrate the radio window. These waves can very efficiently transfer their energy to the electrons if the incident frequency is near the second harmonic of the cyclotron frequency
Electromagnetic waves in an axion-active relativistic plasma non-minimally coupled to gravity
International Nuclear Information System (INIS)
Balakin, Alexander B.; Muharlyamov, Ruslan K.; Zayats, Alexei E.
2013-01-01
We consider cosmological applications of a new self-consistent system of equations, accounting for a non-minimal coupling of the gravitational, electromagnetic and pseudoscalar (axion) fields in a relativistic plasma. We focus on dispersion relations for electromagnetic perturbations in an initially isotropic ultrarelativistic plasma coupled to the gravitational and axion fields in the framework of isotropic homogeneous cosmological model of the de Sitter type. We classify the longitudinal and transversal electromagnetic modes in an axionically active plasma and distinguish between waves (damping, instable or running), and nonharmonic perturbations (damping or instable). We show that for the special choice of the guiding model parameters the transversal electromagnetic waves in the axionically active plasma, non-minimally coupled to gravity, can propagate with the phase velocity smaller than the speed of light in vacuum, thus displaying a possibility for a new type of resonant particle-wave interactions. (orig.)
Electromagnetic computer simulations of collective ion acceleration by a relativistic electron beam
International Nuclear Information System (INIS)
Galvez, M.; Gisler, G.R.
1988-01-01
A 2.5 electromagnetic particle-in-cell computer code is used to study the collective ion acceleration when a relativistic electron beam is injected into a drift tube partially filled with cold neutral plasma. The simulations of this system reveals that the ions are subject to electrostatic acceleration by an electrostatic potential that forms behind the head of the beam. This electrostatic potential develops soon after the beam is injected into the drift tube, drifts with the beam, and eventually settles to a fixed position. At later times, this electrostatic potential becomes a virtual cathode. When the permanent position of the electrostatic potential is at the edge of the plasma or further up, then ions are accelerated forward and a unidirectional ion flow is obtained otherwise a bidirectional ion flow occurs. The ions that achieve higher energy are those which drift with the negative potential. When the plasma density is varied, the simulations show that optimum acceleration occurs when the density ratio between the beam (n b ) and the plasma (n o ) is unity. Simulations were carried out by changing the ion mass. The results of these simulations corroborate the hypothesis that the ion acceleration mechanism is purely electrostatic, so that the ion acceleration depends inversely on the charge particle mass. The simulations also show that the ion maximum energy increased logarithmically with the electron beam energy and proportional with the beam current
Deorbit efficiency assessment through numerical simulation of electromagnetic tether devices
Directory of Open Access Journals (Sweden)
Alexandru IONEL
2016-03-01
Full Text Available This paper examines the deorbit efficiency of an electromagnetic tether deorbit device when used to deorbit an upper stage at end of mission from low Earth orbit. This is done via a numerical simulation in Matlab R2013a, using ode45, taking into account perturbations on the upper stage’s trajectory. The perturbations taken into account are the atmospheric drag, the 3rd body (Sun and Moon, and Earth’s gravitational potential expanded into spherical harmonics.
Multi-scale simulation for plasma science
Energy Technology Data Exchange (ETDEWEB)
Ishiguro, S; Usami, S; Horiuchi, R; Ohtani, H; Maluckov, A; Skoric, M M, E-mail: ishiguro.seiji@nifs.ac.jp
2010-11-01
In order to perform a computer simulation of a large time and spatial scale system, such as a fusion plasma device and solar-terrestrial plasma, macro simulation model, where micro physics is modeled analytically or empirically, is usually used. However, kinetic effects such as wave-particle interaction play important roles in most of nonlinear plasma phenomena and result in anomalous behavior. This limits the applicability of macro simulation models. In a past few years several attempts have been performed to overcome this difficulty. Two types of multi-scale simulation method for nonlinear plasma science are presented. First one is the Micro-Macro Interconnected Simulation Method (MMIS), where micro model and macro model are connected dynamically through an interface and macro time and space simulation is performed. Second one is the Equation Free Projective Integration Method (EFPI), where macro space and time scale simulation is performed by using only a micro simulator and a sophisticated numerical algorithm.
International Nuclear Information System (INIS)
Martinez, R.M.
1983-01-01
Part One examines the properties of electron cyclotron harmonic waves by means of computer simulation. The electromagnetic cyclotron harmonic modes not previously observed in simulation are emphasized and compared with the better known electrostatic (Bernstein) modes for perpendicular propagation. The investigation is performed by a spectrum analysis (both wavelength and frequency) of the thermal equilibrium electromagnetic fluctuation fields present in the simulation. A numerical solution of the fully electromagnetic dispersion relation shows that extreme frequency resolution is necessary to discern shifts of the electromagnetic mode frequencies from the cyclotron harmonics except at high plasma density or temperature. The simulation results show that at high plasma pressure the amplitude of the electromagnetic modes can become greater than that of the electrostatic modes. Part Two examines the interaction of an external electromagnetic wave with the electrostatic cylotron harmonic modes. The stimulated Raman scattering with an extraordinary wave as the pump is observed to occur in a wavelength regime where it would be prevented by Landau damping in an unmagnetized plasma
Electromagnetic Simulation of CERN accelerator Components and Experimental Applications
Zannini, Carlo; Rumolo, Giovanni
Wakes and impedances of single accelerator elements can be obtained by means of theoretical calculation, electromagnetic (EM) simulations or bench measurements. Since theoretical calculations apply only to simple structures and bench measurements have some intrinsic limitations, EM simulations are used as a reliable tool to determine wakes and impedances. This thesis will focus on the use of time domain 3D CST Particle Studio EM simulations to calculate wakes and/or impedances. First, the results of the EM simulations are compared with known analytical solutions and other codes. In this exercise, the driving and the detuning terms of the wakes/impedances, in the transverse plane, are disentangled for both symmetric and asymmetric geometries. The sensitivity of the simulation results to the numerical parameters is discussed, as well as the limits of the validity of the wake formalism and its extension to the nonlinear regime. Using the CST Wakefield Solver, the SPS kicker impedance contribution is then estima...
Interaction of electromagnetic waves with plasma in the radiation-dominated regime
International Nuclear Information System (INIS)
Bulanov, S.V.; Esirkepov, T.Zh.; Koga, J.; Tajima, T.
2004-01-01
A study is made of the main regimes of interaction of relativistically strong electromagnetic waves with plasma under conditions in which the radiation from particles plays a dominant role. The discussion is focused on such issues as the generation of short electromagnetic pulses in the interaction of laser light with clusters and highly efficient ion acceleration in a thin plasma slab under the action of the ponderomotive pressure of the wave. An approach is developed for generating superintense electromagnetic pulses by means of up-to-date laser devices
Theory and simulation of laser plasma coupling
International Nuclear Information System (INIS)
Kruer, W.L.
1979-01-01
The theory and simulation of these coupling processes are considered. Particular emphasis is given to their nonlinear evolution. First a brief introduction to computer simulation of plasmas using particle codes is given. Then the absorption of light via the generation of plasma waves is considered, followed by a discussion of stimulated scattering of intense light. Finally these calculations are compared with experimental results
Characterizing Hypervelocity Impact Plasma Through Experiments and Simulations
Close, Sigrid; Lee, Nicolas; Fletcher, Alex; Nuttall, Andrew; Hew, Monica; Tarantino, Paul
2017-10-01
Hypervelocity micro particles, including meteoroids and space debris with masses produce a strong electromagnetic pulse (EMP) with a broad frequency spectrum. Subsequent plasma oscillations resulting from instabilities can also emit significant power and may be responsible for many reported satellite anomalies. We present theory and recent results from ground-based impact tests aimed at characterizing hypervelocity impact plasma. We also show results from particle-in-cell (PIC) and computational fluid dynamics (CFD) simulations that allow us to extend to regimes not currently possible with ground-based technology. We show that significant impact-produced radio frequency (RF) emissions occurred in frequencies ranging from VHF through L-band and that these emissions were highly correlated with fast (>20 km/s) impacts that produced a fully ionized plasma.
A new scheme to treat the numerical Tcherenkov instability for electromagnetic particle simulations
International Nuclear Information System (INIS)
Assous, F.; Degond, P.; Segre, J.; Degond, P.
1997-10-01
The aim of this paper is to present a new explicit time scheme for electromagnetic particle simulations. The main property of this new scheme, which depends on a parameter, is to reduce and in some cases to suppress numerical instabilities that can appear in this context, and are widely described in the literature. Other numerical properties are also investigated, and a numerical example is finally given to illustrate our purpose. This scheme is expected to be useful in the field of plasma modelling. (authors)
QUICKSILVER emdash A general tool for electromagnetic PIC simulation
International Nuclear Information System (INIS)
Seidel, D.B.; Coats, R.S.; Johnson, W.A.; Kiefer, M.L.; Mix, L.P.; Pasik, M.F.; Pointon, T.D.; Quintenz, J.P.; Riley, D.J.; Turner, C.D.
1997-01-01
The dramatic increase in computational capability that has occurred over the last ten years has allowed fully electromagnetic simulations of large, complex, three-dimensional systems to move progressively from impractical, to expensive, and recently, to routine and widespread. This is particularly true for systems that require the motion of free charge to be self-consistently treated. The QUICKSILVER electromagnetic Particle-In-Cell (EM-PIC) code has been developed at Sandia National Laboratories to provide a general tool to simulate a wide variety of such systems. This tool has found widespread use for many diverse applications, including high-current electron and ion diodes, magnetically insulated power transmission systems, high-power microwave oscillators, high-frequency digital and analog integrated circuit packages, microwave integrated circuit components, antenna systems, radar cross-section applications, and electromagnetic interaction with biological material. This paper will give a brief overview of QUICKSILVER and provide some thoughts on its future development. copyright 1997 American Institute of Physics
Effect of remote field electromagnetic boundary conditions on microwave-induced plasma torches
Jimenez-Diaz, M.; van Dijk, J.; van der Mullen, J. J. A. M.
2011-04-01
A flexible versatile electromagnetic model constructed with the PLASIMO platform is employed to explore electromagnetic features of microwave-induced plasma torches. The bases, formed by a full-vector formulation of the Maxwell equations, provide the possibility to formulate the boundary conditions in a natural way. Together with the use of a direct matrix solver this gives a convergence speed-up of more than a factor of 100 when compared with a scalar formulation on an azimuthal magnetic field that uses an iterative solver. As a result, this electromagnetic model is ready to act in future studies as part of the self-consistent description of plasma-electromagnetic coupling. With the electromagnetic model three types of configuration were studied: the closed, semi-open and open configurations, all three based on the same simplified model plasmas. It is found that the closed configuration, acting as a cavity for which (de)tuning is extremely sensitive for the plasma conditions, is less suitable for applications in which changes in plasma compositions can be expected. The semi-open configuration can be seen as a model for the practice often used in laboratories to place microwave-induced plasma torches in a grid that aims at protecting the environment against microwave electromagnetic radiation. Calculations show that this is good practice provided the radius of this cylindrical grid is in the order of 90 mm. For the most often used configuration, the open version, we found that the power balance as expressed by the coefficients of absorption, transmission and reflection depends on the electron density of the plasma. The reason is that the plasma acts as an antenna, which converts the electromagnetic waves from the coaxial structure to that of the expansion region, and that this antenna function depends on the electron density. The influence of various other antenna elements is investigated as well.
Electromagnetic particle in cell modeling of the plasma focus: Current sheath formation and lift off
International Nuclear Information System (INIS)
Seng, Y. S.; Lee, P.; Rawat, R. S.
2014-01-01
The shaping and formation of the current sheath takes place in the breakdown phase of a plasma focus device and critically controls the device performance. Electrostatic particle in cell codes, with magnetic effects ignored, have been used to model the breakdown phase. This Letter reports the successful development and implementation of an electromagnetic particle in cell (EMPIC) code, including magnetic effects self-consistently, to simulate the breakdown phase; from the ionization, localization and gliding discharge along the insulator to the time instant of current sheath lift off. The magnetic field was found to be appreciable from the time the current sheath came into contact with the anode with increased local current, initiating the voltage breakdown of the device as a result
Galerkin algorithm for multidimensional plasma simulation codes. Informal report
International Nuclear Information System (INIS)
Godfrey, B.B.
1979-03-01
A Galerkin finite element differencing scheme has been developed for a computer simulation of plasmas. The new difference equations identically satisfy an equation of continuity. Thus, the usual current correction procedure, involving inversion of Poisson's equation, is unnecessary. The algorithm is free of many numerical Cherenkov instabilities. This differencing scheme has been implemented in CCUBE, an already existing relativistic, electromagnetic, two-dimensional PIC code in arbitrary separable, orthogonal coordinates. The separability constraint is eliminated by the new algorithm. The new version of CCUBE exhibits good stability and accuracy with reduced computer memory and time requirements. Details of the algorithm and its implementation are presented
International Nuclear Information System (INIS)
Uda, T.; Tanaka, M.; Kawano, T.; Kamimura, Y.; Wang, J.; Fujiwara, O.
2008-01-01
Full text: Nuclear fusion research has been increased worldwide to develop new reliable energy source. In order to occur nuclear fusion reaction extremely high temperature plasma must be confined by magnet. Plasma confinement physics and technology has been studied by such as the large helical device LHD, which is using super conducting magnet system and plasma heating devices by electromagnetic waves. In the large magnetic fusion experimental facility, various electric power devices have potential to exposure workers by leakage of electromagnetic fields. Regarding the environmental safety static magnetic field and variable electromagnetic fields had been monitored around the LHD and related devices. Many kinds of electric power devices of which frequencies distribute from static magnetic field to high frequency of electromagnetic waves. The magnetic strength of LHD is about 3 T and workers are restricted to enter into the LHD hall, but there are many workers in the building. Environmental magnetic strength at the fixed point, where is 23 m far from the center of LHD, had been continuously measured with Gauss Meter 9900 (F.W. Bell) since the first plasma in 1998. After the plasma experiment background level was increased to about 0.06 m T, which is a double of terrestrial magnetic field. It was increased to 0.1-0.2 m T on the plasma experiment and in the case of the super conducting magnet was quickly decreased for protection of the coils system it was increased to 1 m T in short time. Extremely low frequency ELF of electromagnetic fields are caused mainly around the coil electric power supplies. The ELF magnetic strength was measured with ELT-400 (Narda). Near the supplies it was increased to higher than the occupational restriction level of the ICNIRP guide line. In order to heat ion plasma 38 MHz electromagnetic wave heating are used. Around the electromagnetic wave generators, electromagnetic fields have been continuously measured using EMC-300 EP (Narda) with
International Nuclear Information System (INIS)
Sansonnens, L; Howling, A A; Hollenstein, Ch
2006-01-01
Electromagnetic wave propagation effects can give rise to important limitations for processing uniformity in large area, radio-frequency (rf) capacitive plasma reactors. The electromagnetic wavefield solution is derived for a capacitive, high-frequency, cylindrical reactor with symmetric or asymmetric electrode areas containing a uniform plasma slab. It is shown that only two distinct electromagnetic modes are necessary and sufficient to determine the electromagnetic fields everywhere within the reactor except close to the sidewalls. The first mode gives rise to the interelectrode rf voltage standing wave effect associated with high frequencies in large area reactors, and the second mode gives rise to the telegraph effect associated with asymmetric electrode areas, which necessitates the redistribution of rf current along the plasma to maintain rf current continuity. This work gives a unified treatment of both effects which have previously been studied separately, experimentally and theoretically, in the literature. The equivalent circuit of each mode is also derived from its respective dispersion relation. Examples of this electromagnetic wavefield solution show that both modes can cause nonuniformity of the plasma rf potential, depending on the reactor geometry, excitation frequency and plasma permittivity and sheath width, which has consequences for large-area plasma processing
Energy Technology Data Exchange (ETDEWEB)
Light, Max Eugene [Los Alamos National Laboratory
2017-04-13
This report outlines the theory underlying electromagnetic (EM) wave propagation in an unmagnetized, inhomogeneous plasma. The inhomogeneity is given by a spatially nonuniform plasma electron density n_{e}(r), which will modify the wave propagation in the direction of the gradient rn_{e}(r).
External circuit integration with electromagnetic particle in cell modeling of plasma focus devices
International Nuclear Information System (INIS)
Seng, Y. S.; Lee, P.; Rawat, R. S.
2015-01-01
The pinch performance of a plasma focus (PF) device is sensitive to the physical conditions of the breakdown phase. It is therefore essential to model and study the initial phase in order to optimize device performance. An external circuit is self consistently coupled to the electromagnetic particle in cell code to model the breakdown and initial lift phase of the United Nations University/International Centre for Theoretical Physics (UNU-ICTP) plasma focus device. Gas breakdown during the breakdown phase is simulated successfully, following a drop in the applied voltage across the device and a concurrent substantial rise in the circuit current. As a result, the plasma becomes magnetized, with the growing value of the magnetic field over time leading to the gradual lift off of the well formed current sheath into the axial acceleration phase. This lifting off, with simultaneous outward sheath motion along the anode and vertical cathode, and the strong magnetic fields in the current sheath region, was demonstrated in this work, and hence validates our method of coupling the external circuit to PF devices. Our method produces voltage waveforms that are qualitatively similar to the observed experimental voltage profiles of the UNU-ICTP device. Values of the mean electron energy before and after voltage breakdown turned out to be different, with the values after breakdown being much lower. In both cases, the electron energy density function turned out to be non-Maxwellian
Study on the electromagnetic waves propagation characteristics in partially ionized plasma slabs
Directory of Open Access Journals (Sweden)
Zhi-Bin Wang
2016-05-01
Full Text Available Propagation characteristics of electromagnetic (EM waves in partially ionized plasma slabs are studied in this paper. Such features are significant to applications in plasma antennas, blackout of re-entry flying vehicles, wave energy injection to plasmas, and etc. We in this paper developed a theoretical model of EM wave propagation perpendicular to a plasma slab with a one-dimensional density inhomogeneity along propagation direction to investigate essential characteristics of EM wave propagation in nonuniform plasmas. Particularly, the EM wave propagation in sub-wavelength plasma slabs, where the geometric optics approximation fails, is studied and in comparison with thicker slabs where the geometric optics approximation applies. The influences of both plasma and collisional frequencies, as well as the width of the plasma slab, on the EM wave propagation characteristics are discussed. The results can help the further understanding of propagation behaviours of EM waves in nonuniform plasma, and applications of the interactions between EM waves and plasmas.
3D simulation of superconducting microwave devices with an electromagnetic-field simulator
International Nuclear Information System (INIS)
Takeuchi, N.; Yamanashi, Y.; Saito, Y.; Yoshikawa, N.
2009-01-01
High-frequency microwave applications, such as filters, delay lines, and resonators, are quite important for superconducting electronic devices. In order to design the superconducting microwave devices, circuit parameters should be precisely extracted from the physical structure of the devices. A 3-dimensional electromagnetic-field simulator is very useful for designing microwave devices. However, designing of superconducting microwave devices using a conventional 3D electromagnetic-field simulator is difficult because most of commercially available 3D electromagnetic-field simulators can not exactly characterize electromagnetic phenomena of superconductors. In this study, a novel calculation method of superconducting microwave devices, which can be applicable to a conventional 3D electromagnetic-field simulator, has been proposed. Calculation results of characteristic impedance of superconducting microstrip lines show very good agreements with the theoretically calculated vales. The frequency response of a superconducting Nb microwave filter designed by the proposed calculation method agrees well with the experimental results. This calculation method enables us to precisely estimate microwave characteristics of superconducting devices.
Numerical simulation of compact intracloud discharge and generated electromagnetic pulse
Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.
2015-06-01
Using the concept of the relativistic runaway electron avalanche, numerical simulation of compact intracloud discharge as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-UHF range was conducted. We evaluated the numbers of electrons initiating the avalanche, with which the calculated EMP characteristics are consistent with measured ones. The discharge capable of generating EMPs produces runaway electrons in numbers close to those in the source of terrestrial γ-flashes (TGF) registered in the nearest space, which may be an argument for a joint EMP and TGF source.
Boundary Plasma Turbulence Simulations for Tokamaks
International Nuclear Information System (INIS)
Xu, X.; Umansky, M.; Dudson, B.; Snyder, P.
2008-05-01
The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T e ; T i ) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics
Deca, J.; Divin, A.; Lapenta, G.; Lembège, B.; Markidis, S.; Horányi, M.
2014-04-01
We present the first three-dimensional fully kinetic and electromagnetic simulations of the solar wind interaction with lunar crustal magnetic anomalies (LMAs). Using the implicit particle-in-cell code iPic3D, we confirm that LMAs may indeed be strong enough to stand off the solar wind from directly impacting the lunar surface forming a mini-magnetosphere, as suggested by spacecraft observations and theory. In contrast to earlier magnetohydrodynamics and hybrid simulations, the fully kinetic nature of iPic3D allows us to investigate the space charge effects and in particular the electron dynamics dominating the near-surface lunar plasma environment. We describe for the first time the interaction of a dipole model centered just below the lunar surface under plasma conditions such that only the electron population is magnetized. The fully kinetic treatment identifies electromagnetic modes that alter the magnetic field at scales determined by the electron physics. Driven by strong pressure anisotropies, the mini-magnetosphere is unstable over time, leading to only temporal shielding of the surface underneath. Future human exploration as well as lunar science in general therefore hinges on a better understanding of LMAs.
Rothwell, Edward J
2009-01-01
Introductory concepts Notation, conventions, and symbology The field concept of electromagneticsThe sources of the electromagnetic field Problems Maxwell's theory of electromagnetism The postulate Maxwell's equations in moving frames The Maxwell-Boffi equations Large-scale form of Maxwell's equationsThe nature of the four field quantities Maxwell's equations with magnetic sources Boundary (jump) conditions Fundamental theorems The wave nature of the electromagnetic field ProblemsThe static electromagnetic field Static fields and steady currents ElectrostaticsMagnetostatics Static field theorem
Underwater Electromagnetic Sensor Networks, Part II: Localization and Network Simulations
Directory of Open Access Journals (Sweden)
Javier Zazo
2016-12-01
Full Text Available In the first part of the paper, we modeled and characterized the underwater radio channel in shallowwaters. In the second part,we analyze the application requirements for an underwaterwireless sensor network (U-WSN operating in the same environment and perform detailed simulations. We consider two localization applications, namely self-localization and navigation aid, and propose algorithms that work well under the specific constraints associated with U-WSN, namely low connectivity, low data rates and high packet loss probability. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network using a low number of anchor nodes and distance measurements from the underwater channel. Once the network has been self-located, we consider a node estimating its position for underwater navigation communicating with neighboring nodes. We also propose a communication system and simulate the whole electromagnetic U-WSN in the Castalia simulator to evaluate the network performance, including propagation impairments (e.g., noise, interference, radio parameters (e.g., modulation scheme, bandwidth, transmit power, hardware limitations (e.g., clock drift, transmission buffer and complete MAC and routing protocols. We also explain the changes that have to be done to Castalia in order to perform the simulations. In addition, we propose a parametric model of the communication channel that matches well with the results from the first part of this paper. Finally, we provide simulation results for some illustrative scenarios.
Plasma scattering of electromagnetic radiation theory and measurement techniques
Froula, Dustin H; Luhmann, Neville C Jr; Sheffield, John
2011-01-01
This work presents one of the most powerful methods of plasma diagnosis in exquisite detail to guide researchers in the theory and measurement techniques of light scattering in plasmas. Light scattering in plasmas is essential in the research and development of fusion energy, environmental solutions, and electronics.Referred to as the "Bible" by researchers the work encompasses fusion and industrial applications essential in plasma research. It is the only comprehensive resource specific to the plasma scattering technique. It provides a wide-range of experimental examples and discussion of the
Electromagnetic and Thermal Simulations of Human Neurons for SAR Applications.
Perez, Felipe; Millholland, Gilbert; Peddinti, Seshasai Vamsi Krishna; Thella, Ashok Kumar; Rizkalla, James; Salama, Paul; Rizkalla, Maher; Morisaki, Jorge; Rizkalla, Maher E
2016-08-01
The impact of the electromagnetic waves (EM) on human neurons (HN) has been under investigation for decades, in efforts to understand the impact of cell phones (radiation) on human health, or radiation absorption by HN for medical diagnosis and treatment. Research issues including the wave frequency, power intensity, reflections and scattering, and penetration depths are of important considerations to be incorporated into the research study. In this study, computer simulation for the EM exposure to HN was studied for the purpose of determining the upper limits of the electric and magnetic field intensities, power consumption, reflections and transmissions, and the change in temperature resulting from the power absorption by human neurons. Both high frequency structural simulators (HFSS) from ANSYS software, and COMSOL multi-physics were used for the simulation of the EM transmissions and reflections, and the temperature profile within the cells, respectively. For the temperature profile estimation, the study considers an electrical source of 0.5 watt input power, 64 MHz. The EM simulation was looking into the uniformity of the fields within the sample cells. The size of the waveguide was set to be appropriate for a small animal model to be conducted in the future. The incident power was fully transmitted throughout the waveguide, and less than 1% reflections were observed from the simulation. The minimum reflected power near the sample under investigation was found to be with negligible reflected field strengths. The temperature profile resulting from the COMSOL simulation was found to be near 0.25 m°K, indicating no change in temperature on the neuro cells under the EM exposure. The paper details the simulation results for the EM response determined by HFSS, and temperature profile simulated by COMSOL.
Blob dynamics simulations for the TJ-K plasma
Energy Technology Data Exchange (ETDEWEB)
Rakha, Allah; Garland, Stephen; Ramisch, Mirko [Institut fuer Grenzflaechenverfahrenstechnik und Plasmatechnologie, Universitaet Stuttgart (Germany); Scott, Bruce [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, D-85748 Garching (Germany)
2015-05-01
Radially propagating filaments elongated along magnetic field lines, known as blobs, are responsible for a major part of particle density and energy cross-field transport in the scrape-off layer (SOL) of fusion devices. Blobs, which are born in the vicinity of the last closed flux surface, are denser and hotter than the background SOL plasma, and can cause damage to plasma facing components. A good understanding of their trajectories is therefore important for the design of future fusion reactors. As the dynamics of blobs in the SOL is governed by nonlinear phenomena, and analytical models are insufficient for their detailed study, nonlinear simulations are necessary to gain a better understanding. First simulations of plasmas with TJ-K equivalent parameters have been carried out using the GEMR gyrofluid code (an energy conserving electromagnetic six field gyrofluid model with radially dependent geometry). The simulation results are compared with experimental data from the TJ-K Stellarator in order to improve the understanding of SOL transport.
Numerical Simulation Modelling for Velocity Measurement of Electromagnetic Flow Meter
International Nuclear Information System (INIS)
Wang, J Z; Gong, C L; Tian, G Y; Lucas, G P
2006-01-01
An induced voltage EMF in the area of measuring single-phase flow rate in pipes has been used in many industrial areas. To measure the continuous phase velocity profile in multiphase flows where the continuous phase is an electrical conductor, Electrical capacitance and resistance tomography has been comprehensively investigated, except for continuous phase velocity profile measurement. This paper tries to design the numerical simulation model according to the basic electromagnetic induction law and to investigate the relationship between induced electric potential or potential drop and the velocity distribution of the conductive continuous phase in the flow. First, the 3-Dimenssion simulating module for EMF is built. Given the most simple velocity profile of the fluid in the pipe, the value of the induced potential difference between electrodes is obtained by simulation and theoretical computation according to J A Shercliff's weight function. The relative error is 6.066 . This proves that the simulation model is accurate enough to investigate the characteristic of the induced potential difference of EMF. Finally, the relationship between induced potential difference and the velocity profile is analysed in detail where the complicated velocity profile is expressed as vz = 1m/s when 0.022< x2+y2< = 0.02652 and vz = 5m/s when x2+y2< = 0.022
International Nuclear Information System (INIS)
Cohen, B.I.
1987-01-01
The existence of compact dispersion relations for parametric instabilities of coherent electromagnetic waves in magnetized plasmas is addressed here. In general, comprehensive dispersion relations for parametric instabilities in unmagnetized plasmas become more complicated in the presence of an applied time-independent magnetic field. This is demonstrated with a fluid perturbation theory. A compact dispersion relation for parametric instabilities in unmagnetized plasma is heuristically extended here to the case of a magnetized plasma. This dispersion relation gives the correct results in a variety of circumstances of interest in considering electron cyclotron heating applications
International Nuclear Information System (INIS)
Kato, Tsunehiko N.; Takabe, Hideaki
2010-01-01
A two-dimensional electromagnetic particle-in-cell simulation with the realistic ion-to-electron mass ratio of 1836 is carried out to investigate the electrostatic collisionless shocks in relatively high-speed (∼3000 km s -1 ) plasma flows and also the influence of both electrostatic and electromagnetic instabilities, which can develop around the shocks, on the shock dynamics. It is shown that the electrostatic ion-ion instability can develop in front of the shocks, where the plasma is under counterstreaming condition, with highly oblique wave vectors as was shown previously. The electrostatic potential generated by the electrostatic ion-ion instability propagating obliquely to the shock surface becomes comparable with the shock potential and finally the shock structure is destroyed. It is also shown that in front of the shock the beam-Weibel instability gradually grows as well, consequently suggesting that the magnetic field generated by the beam-Weibel instability becomes important in long-term evolution of the shock and the Weibel-mediated shock forms long after the electrostatic shock vanished. It is also observed that the secondary electrostatic shock forms in the reflected ions in front of the primary electrostatic shock.
International Nuclear Information System (INIS)
Salem, S.L.; Listvinsky, G.; Lee, M.Y.; Bailey, C.
1987-01-01
Studies of the electromagnetic loads produced by a variety of plasma disruptions, and the resulting structural effects on the compact Ignition Tokamak (CIT) vacuum vessel (VV), have been performed to help optimize the VV design. A series of stationary and moving plasmas, with disruption rates from 0.7--10.0 MA/ms, have been analyzed using the EMPRES code to compute eddy currents and electromagnetic pressures, and the NASTRAN code to evaluate the structural response of the vacuum vessel. Key factors contributing to the magnitude of EM forces and resulting stresses on the vessel have been found to include disruption rate, and direction and synchronization of plasma motion with the onset of plasma current decay. As a result of these analyses, a number of design changes have been made, and design margins for the present 1.75 meter design have been improved over the original CIT configuration. 1 ref., 10 figs., 4 tabs
Guiding-center models for edge plasmas and numerical simulations of isolated plasma filaments
International Nuclear Information System (INIS)
Madsen, Jens
2010-09-01
The work presented in this thesis falls into two categories: development of reduced dynamical models applicable to edge turbulence in magnetically confined fusion plasmas and numerical simulations of isolated plasma filaments in the scrape-off layer region investigating the influence of finite Larmor radius effects on the radial plasma transport. The coexistence of low-frequency fluctuations, having length scales comparable to the ion gyroradius, steep pressure gradients and strong E x B flows in the edge region of fusion plasmas violates the standard gyrokinetic ordering. In this thesis two models are presented that overcome some of the difficulties associated with the development of reduced dynamical models applicable to the edge. Second order guiding-center coordinates are derived using the phasespace Lie transform method. Using a variational principle the corresponding Vlasov-Maxwell equations expressed in guiding-center coordinates are derived including a local energy theorem. The second order terms describe lowest order finite Larmor radius effects. This set of equations might be relevant for edge plasmas due to the capability of capturing strong E x B flows and lowest order finite Larmor radius effects self-consistently. Next, an extension of the existing gyrokinetic formalism with strong flows is presented. In this work the background electric fields is dynamical, whereas earlier contributions did only incorporate a stationary electric field. In an ordering relevant for edge plasma turbulence, fully electromagnetic second order gyrokinetic coordinates and the corresponding gyrokinetic Vlasov-Maxwell equations are derived, including a local energy theorem. By taking the polarization and magnetization densities in the drift kinetic limit, we present the gyrokinetic Vlasov-Maxwell equations in a more tractable form, which could be relevant for direct numerical simulations of edge plasma turbulence. Finally, an investigation of the influence of finite Larmor
Guiding-center models for edge plasmas and numerical simulations of isolated plasma filaments
Energy Technology Data Exchange (ETDEWEB)
Madsen, Jens
2010-09-15
The work presented in this thesis falls into two categories: development of reduced dynamical models applicable to edge turbulence in magnetically confined fusion plasmas and numerical simulations of isolated plasma filaments in the scrape-off layer region investigating the influence of finite Larmor radius effects on the radial plasma transport. The coexistence of low-frequency fluctuations, having length scales comparable to the ion gyroradius, steep pressure gradients and strong E x B flows in the edge region of fusion plasmas violates the standard gyrokinetic ordering. In this thesis two models are presented that overcome some of the difficulties associated with the development of reduced dynamical models applicable to the edge. Second order guiding-center coordinates are derived using the phasespace Lie transform method. Using a variational principle the corresponding Vlasov-Maxwell equations expressed in guiding-center coordinates are derived including a local energy theorem. The second order terms describe lowest order finite Larmor radius effects. This set of equations might be relevant for edge plasmas due to the capability of capturing strong E x B flows and lowest order finite Larmor radius effects self-consistently. Next, an extension of the existing gyrokinetic formalism with strong flows is presented. In this work the background electric fields is dynamical, whereas earlier contributions did only incorporate a stationary electric field. In an ordering relevant for edge plasma turbulence, fully electromagnetic second order gyrokinetic coordinates and the corresponding gyrokinetic Vlasov-Maxwell equations are derived, including a local energy theorem. By taking the polarization and magnetization densities in the drift kinetic limit, we present the gyrokinetic Vlasov-Maxwell equations in a more tractable form, which could be relevant for direct numerical simulations of edge plasma turbulence. Finally, an investigation of the influence of finite Larmor
2016-01-22
Electromagnetic Simulations for an Axisymmetric Gregorian Reflector System for a Space-Deployed Inflatable Antenna Alan J. Fenn Lincoln...system for potential space deployment is explored. The antenna utilizes a planar array located near the vertex of the primary reflector. Numerical...electromagnetic simulations based on the multilevel fast multipole method (MLFMM) were used to analyze and optimize the antenna parameters for
Beam equipment electromagnetic interaction in accelerators: simulation and experimental benchmarking
Passarelli, Andrea; Vaccaro, Vittorio Giorgio; Massa, Rita; Masullo, Maria Rosaria
One of the most significant technological problems to achieve the nominal performances in the Large Hadron Collider (LHC) concerns the system of collimation of particle beams. The use of collimators crystals, exploiting the channeling effect on extracted beam, has been experimentally demonstrated. The first part of this thesis is about the optimization of UA9 goniometer at CERN, this device used for beam collimation will replace a part of the vacuum chamber. The optimization process, however, requires the calculation of the coupling impedance between the circulating beam and this structure in order to define the threshold of admissible intensity to do not trigger instability processes. Simulations have been performed with electromagnetic codes to evaluate the coupling impedance and to assess the beam-structure interaction. The results clearly showed that the most concerned resonance frequencies are due solely to the open cavity to the compartment of the motors and position sensors considering the crystal in o...
First experience of vectorizing electromagnetic physics models for detector simulation
Energy Technology Data Exchange (ETDEWEB)
Amadio, G. [Sao Paulo State U.; Apostolakis, J. [CERN; Bandieramonte, M. [Catania Astrophys. Observ.; Bianchini, C. [Mackenzie Presbiteriana U.; Bitzes, G. [CERN; Brun, R. [CERN; Canal, P. [Fermilab; Carminati, F. [CERN; Licht, J.de Fine [U. Copenhagen (main); Duhem, L. [Intel, Santa Clara; Elvira, D. [Fermilab; Gheata, A. [CERN; Jun, S. Y. [Fermilab; Lima, G. [Fermilab; Novak, M. [CERN; Presbyterian, M. [Bhabha Atomic Res. Ctr.; Shadura, O. [CERN; Seghal, R. [Bhabha Atomic Res. Ctr.; Wenzel, S. [CERN
2015-12-23
The recent emergence of hardware architectures characterized by many-core or accelerated processors has opened new opportunities for concurrent programming models taking advantage of both SIMD and SIMT architectures. The GeantV vector prototype for detector simulations has been designed to exploit both the vector capability of mainstream CPUs and multi-threading capabilities of coprocessors including NVidia GPUs and Intel Xeon Phi. The characteristics of these architectures are very different in terms of the vectorization depth, parallelization needed to achieve optimal performance or memory access latency and speed. An additional challenge is to avoid the code duplication often inherent to supporting heterogeneous platforms. In this paper we present the first experience of vectorizing electromagnetic physics models developed for the GeantV project.
Plasma crystals: experiments and simulation
Piel, A.
2017-01-01
Dusty plasmas are a well accessible system to study crystallization of charged-particle systems at room temperature. The large mass compared to atomic particles dramatically slows down the particle velocities. The high transparency of the system allows to trace simultaneously the motion of all particles with quasi-atomic resolution. After a brief overview, the progress in this field is exemplified by studies of spherical three-dimensional plasma crystals, the so-called Yukawa balls. The static structure and eigenmodes are explained in simple terms. It is shown that shielding modifies the expansion of a Yukawa ball from a self-similar explosion to a continuous ablation process that starts at the surface. The experimental progress with three-dimensional diagnostics and laser heating and sophisticated methods for visualising the order inside the shell structure are described. Together with quantifying the diffusion coefficient these investigations reveal the details of the solid-liquid phase transition. Besides thermodynamic aspects, the liquid phase of dusty plasmas also gives access to hydrodynamic phenomena at the individual particle scale.
A Concept for Directly Coupled Pulsed Electromagnetic Acceleration of Plasmas
Thio, Y.C. Francis; Cassibry, Jason T.; Eskridge, Richard; Smith, James; Wu, S. T.; Rodgers, Stephen L. (Technical Monitor)
2001-01-01
Plasma jets with high momentum flux density are required for a variety of applications in propulsion research. Methods of producing these plasma jets are being investigated at NASA Marshall Space Flight Center. The experimental goal in the immediate future is to develop plasma accelerators which are capable of producing plasma jets with momentum flux density represented by velocities up to 200 km/s and ion density up to 10(exp 24) per cu m, with sufficient precision and reproducibility in their properties, and with sufficiently high efficiency. The jets must be sufficiently focused to allow them to be transported over several meters. A plasma accelerator concept is presented that might be able to meet these requirements. It is a self-switching, shaped coaxial pulsed plasma thruster, with focusing of the plasma flow by shaping muzzle current distribution as in plasma focus devices, and by mechanical tapering of the gun walls. Some 2-D MHD modeling in support of the conceptual design will be presented.
International Nuclear Information System (INIS)
Li Hanyu; Zhou Haijing; Dong Zhiwei; Liao Cheng; Chang Lei; Cao Xiaolin; Xiao Li
2010-01-01
A large-scale parallel electromagnetic field simulation program JEMS-FDTD(J Electromagnetic Solver-Finite Difference Time Domain) is designed and implemented on JASMIN (J parallel Adaptive Structured Mesh applications INfrastructure). This program can simulate propagation, radiation, couple of electromagnetic field by solving Maxwell equations on structured mesh explicitly with FDTD method. JEMS-FDTD is able to simulate billion-mesh-scale problems on thousands of processors. In this article, the program is verified by simulating the radiation of an electric dipole. A beam waveguide is simulated to demonstrate the capability of large scale parallel computation. A parallel performance test indicates that a high parallel efficiency is obtained. (authors)
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.
Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode
Poehlmann, Flavio R.; Cappelli, Mark A.; Rieker, Gregory B.
2010-01-01
Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma def...
Resting charge potential in a magnetoactive plasma in an alternating electromagnetic field
International Nuclear Information System (INIS)
Uryupin, S.A.
1982-01-01
The effect of a strong constant magnetic field on the resting charge potential in plasma in a high-frequency electromagnetic field is investigated. The potential ''magnetic anysotropy'' caused by the change in electron trajectories in the alternating electromagnetic field under the effect of a constant magnetic field is revealed. The influence of the finite value of electromagnetic radiation wave length of the test charqe potential is studied. It is shown that at the distances from ion, small as compared with the wave length r > lambda and r >> rsub(D) (rsub(D)- Debye electron radius) the potential form essentially depends on wave length value as well as on direction of propagation of electromagnetic radiation. However the statement on existence of charge field ''descreening'' obtained under the conditions rsub(D) lambda distances as well
DEFF Research Database (Denmark)
Smistrup, Kristian; Hansen, Ole; Bruus, Henrik
2005-01-01
We present experiments and simulations of magnetic separation of magnetic beads in a microfluidic channel. The separation is obtained by microfabricated electromagnets. The results of our simulations using FEMLAB and Mathematica are compared with experimental results obtained using our own...
International Nuclear Information System (INIS)
Tirsky, V.V.; Ledenev, V.G.; Tomozov, V.M.
2001-01-01
We consider the process of generation of electromagnetic waves as a consequence of the merging of two Langmuir plasmons. The case of a hot plasma in a magnetic field is investigated. It is shown that under such conditions the frequency of Langmuir plasmons can vary over the range from 0.8 to 1.1 of the Langmuir frequency of electrons. The spectrum and polarization of electromagnetic radiation are analyzed. It is shown that allowance for the thermal motion of plasma particles under the conditions involved permits electromagnetic waves in the range from 1.6 to 2.2 of the Langmuir frequency of electrons to be generated. The degree of circular polarization of the radiation can reach 50% even in the case of an isotropic spectrum of Langmuir turbulence. (orig.)
Non linear dynamic of Langmuir and electromagnetic waves in space plasmas
International Nuclear Information System (INIS)
Guede, Jose Ricardo Abalde
1995-11-01
The aim of this work is to study the nonlinear dynamics of Langmuir and electromagnetic waves in space plasmas. Firstly, the generalized Zakharov equations are derived which are used to study the hybrid parametric instability involving the generation of daughter Langmuir, electromagnetic and ion-acoustic waves induced by two counter-propagating Langmuir pump waves with different amplitudes based on a coupled dispersion relation. Secondly, starting from the generalized Zakharov equations the linear and nonlinear coupled mode theories of three-wave and four-wave parametric interactions are developed, respectively. In three-waves processes, a Langmuir wave decays into another Langmuir wave and an ion-acoustic wave (electrostatic parametric decay) or into an electromagnetic wave and an ion-acoustic wave (electromagnetic parametric decay). In four-wave (modulational) processes, the interaction involves two wave triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplet the coupling of a pump wave with a low-frequency wave generate an anti-Stokes wave. These modulational processes are convective and resonant processes wherein the low-frequency modes are Eigenmodes of plasma and are known as the stimulated modulational processes. Four such processes are investigated in this thesis: two with Langmuir pump waves (electrostatic and hybrid stimulated modulation processes) and the other two with electromagnetic pump waves (stimulated modulation Brillouin scattering and electromagnetic stimulated modulation process). Applications of the theoretical results in space plasmas are discussed. In particular, it is shown that the electrostatic and electromagnetic parametric decay processes of Langmuir waves can model the generation and modulation of radio emissions and Langmuir waves in the
Effect of frequency variation on electromagnetic pulse interaction with charges and plasma
Khachatryan, A.G.; van Goor, F.A.; Verschuur, Jeroen W.J.; Boller, Klaus J.
2005-01-01
The effect of frequency variation (chirp) in an electromagnetic (EM) pulse on the pulse interaction with a charged particle and plasma is studied. Various types of chirp and pulse envelopes are considered. In vacuum, a charged particle receives a kick in the polarization direction after interaction
Computer simulation of complexity in plasmas
International Nuclear Information System (INIS)
Hayashi, Takaya; Sato, Tetsuya
1998-01-01
By making a comprehensive comparative study of many self-organizing phenomena occurring in magnetohydrodynamics and kinetic plasmas, we came up with a hypothetical grand view of self-organization. This assertion is confirmed by a recent computer simulation for a broader science field, specifically, the structure formation of short polymer chains, where the nature of the interaction is completely different from that of plasmas. It is found that the formation of the global orientation order proceeds stepwise. (author)
Theory and Simulations of Solar System Plasmas
Goldstein, Melvyn L.
2011-01-01
"Theory and simulations of solar system plasmas" aims to highlight results from microscopic to global scales, achieved by theoretical investigations and numerical simulations of the plasma dynamics in the solar system. The theoretical approach must allow evidencing the universality of the phenomena being considered, whatever the region is where their role is studied; at the Sun, in the solar corona, in the interplanetary space or in planetary magnetospheres. All possible theoretical issues concerning plasma dynamics are welcome, especially those using numerical models and simulations, since these tools are mandatory whenever analytical treatments fail, in particular when complex nonlinear phenomena are at work. Comparative studies for ongoing missions like Cassini, Cluster, Demeter, Stereo, Wind, SDO, Hinode, as well as those preparing future missions and proposals, like, e.g., MMS and Solar Orbiter, are especially encouraged.
Towards a realistic plasma simulation code
International Nuclear Information System (INIS)
Anderson, D.V.
1991-06-01
Several new developments in the technology of simulating plasmas, both in particle and fluid models, now allow a stage of synthesis in which many of these advances can be combined into one simulation model. Accuracy and efficiency are the criteria to be satisfied in this quest. We want to build on the following research: 1. the development of the δf method of Barnes. 2. The moving node Galerkin model of Glasser, Miller and Carlson. 3. Particle moving schemes on unstructured grids by Ambrosiano and Bradon. 4. Particle simulations using sorted particles Anderson and Shumaker. Rather than being competing developments,these presumably can be combined into one computational model. We begin by summarizing the physics model for the plasma. The Vlasov equation can be solved as an initial value problem by integrating the plasma distribution function forward in time. 5 refs
Simulation of current generation in a 3-D plasma model
International Nuclear Information System (INIS)
Tsung, F.S.; Dawson, J.M.
1996-01-01
Two wires carrying current in the same direction will attract each other, and two wires carrying current in the opposite direction will repel each other. Now, consider a test charge in a plasma. If the test charge carries current parallel to the plasma, then it will be pulled toward the plasma core, and if the test charge carries current anti-parallel to the plasma, then it will be pushed to the edge. The electromagnetic coupling between the plasma and a test charge (i.e., the A parallel circ v parallel term in the test charge's Hamiltonian) breaks the symmetry in the parallel direction, and gives rise to a diffusion coefficient which is dependent on the particle's parallel velocity. This is the basis for the open-quotes preferential lossclose quotes mechanism described in the work by Nunan et al. In our previous 2+1/2 D work, in both cylindrical and toroidal geometries, showed that if the plasma column is centrally fueled, then an initial current increases steadily. The results in straight, cylindrical plasmas showed that self generated parallel current arises without trapped particle or neoclassical diffusion, as assumed by the bootstrap theory. It suggests that the fundamental mechanism seems to be the conservation of particles canonical momenta in the direction of the ignorable coordinate. We have extended the simulation to 3D to verify the model put forth. A scalable 3D EM-PIC code, with a localized field-solver, has been implemented to run on a large class of parallel computers. On the 512-node SP2 at Cornell Theory Center, we have benchmarked the 2+1/2 D calculations using 32 grids in the previously ignored direction, and a 100-fold increase in the number of particles. Our preliminary results show good agreements between the 2+1/2 D and the 3D calculations. We will present our 3D results at the meeting
Issues in direct numerical simulation of plasma turbulence and transport
Thyagaraja, A.; Arter, W.; Haas, F. A.
1991-04-01
The problem of direct numerical simulation of plasma turbulence in magnetic confinement systems such as a tokamak is important in gaining a theoretical understanding of anomalous transport of particles, energy, momentum and impurities in such systems. Two approaches to this question are being developed. The design philosophy and the basic numerical problems encountered and solved in the construction of a two-fluid, 3-D, electro-magnetic, finite difference, time evolution code, CUTIE, are outlined. The importance of qualitative consistency, time-reversal, conservation properties, phase mixing, and boundary conditions are illustrated in the context of both passive and active electrostatic turbulence. A separate study was undertaken to aid in the understanding of drift wave turbulence in tokamak plasmas. In this connection a 3-D, time-dependant, electrostatic drift wave code called DRIFT was written. This has features which take account of toroidicity, non-adiabaticity and magnetic shear. The resulting code is very flexible, and was used to solve the Hasegawa-Mima equation efficiently in 2-D. Results from time-dependant, 3-D calculation run on a Cray-2 are presented. The aim is to obtain a proper physical understanding of plasma turbulence in typical tokamak conditions by calculating the power spectra of the turbulent fluctuations and their transport consequences. It is believed that this can only be achieved by a step-by-step approach to the numerics, making sure that the calculated effects represent genuine physics and are not mere artifacts of the numerical simulation.
Numerical simulation of a novel non-transferred arc plasma torch operating with nitrogen
International Nuclear Information System (INIS)
Hiremath, Gavisiddayya; Kandasamy, Ramachandran; Ganesh, Ravi
2015-01-01
High power plasma torches with higher electro-thermal efficiency are required for industrial applications. To increase the plasma power and electrothermal efficiency, conventional torches are being modified to operate with molecular gases such as air and nitrogen. Since increasing arc current enhances the heat loss to the anode, torches are being developed to operate under high voltage and low current. The plasma flow dynamics and electromagnetic coupling with plasma flow inside the torch etc. are highly complex and knowledge on the same is required to develop high torches with higher efficiency. Unfortunately detailed experimentation on the same is very difficult. Numerical modeling and simulation is one of the best tools to understand the physics involved in such complex processes. A 2D numerical model is developed to simulate the characteristics of the plasma inside the torch. Though plasma is not in local thermodynamic equilibrium (LTE) close to the electrodes, LTE is assumed everywhere in the plasma to avoid complex and time consuming calculations. Other valid assumptions used in the model are plasma flow is optically thin, laminar and incompressible. Flow, energy and electromagnetic equations are solved with appropriate boundary conditions and volume sources using SIMPLE algorithm with finite volume method. Temperature dependent thermophysical properties of nitrogen are used for the simulations. Simulations are carried out for different experimental conditions. The effects of arc current, gas flow rate of plasma generating gas and sheath gas injected above the bottom anode on the arc voltage, electrothermal efficiency of the torch, plasma temperature and plasma velocity are simulated. Predicted results are compared with experimental results. (author)
Electromagnetic waves in uniaxial anisotropic chiral waveguides in magnetized plasma
Ghaffar, A.; Alkanhal, Majeed A. S.
2015-07-01
The characteristics of guided modes in circular waveguides of a uniaxial anisotropic chiral core and a cladding filled with anisotropic plasma are presented. The cladding region is assumed to be infinitely extended with an external applied magnetic field oriented along the direction of propagation in the waveguide. The characteristics equation for the modes in this waveguide are obtained. The variations of the propagation properties with the plasma parameters, chiral parameters, and the cyclotron frequency of plasma have been investigated. Particularly, the effects of the chirality and the cyclotron frequency of plasma on the magnitude and orientation of the energy flux of the guided modes for three kinds of uniaxial anisotropic chiral media have been numerically investigated. Comparisons of the computed results of the presented formulations with published results for some special cases confirm the accuracy of the presented analyses.
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.
Electromagnetic plasma wave emissions from the auroral field lines
Gurnett, D. A.
1978-01-01
The most important types of auroral radio emissions are reviewed. Particular attention is given to the following four types of electromagnetic emissions: auroral hiss, saucers, ELF noise bands, and auroral kilometric radiation. It is shown that the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances in the range of 2.5-5 earth radii, probably in direct association with auroral-particle acceleration by parallel electric fields. The auroral hiss appears to be generated by amplified Cerenkov radiation. Several mechanisms are proposed for the auroral kilometric radiation, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.
MHD simulation of plasma compression experiments
Reynolds, Meritt; Barsky, Sandra; de Vietien, Peter
2017-10-01
General Fusion (GF) is working to build a magnetized target fusion (MTF) power plant based on compression of magnetically-confined plasma by liquid metal. GF is testing this compression concept by collapsing solid aluminum liners onto plasmas formed by coaxial helicity injection in a series of experiments called PCS (Plasma Compression, Small). We simulate the PCS experiments using the finite-volume MHD code VAC. The single-fluid plasma model includes temperature-dependent resistivity and anisotropic heat transport. The time-dependent curvilinear mesh for MHD simulation is derived from LS-DYNA simulations of actual field tests of liner implosion. We will discuss how 3D simulations reproduced instability observed in the PCS13 experiment and correctly predicted stabilization of PCS14 by ramping the shaft current during compression. We will also present a comparison of simulated Mirnov and x-ray diagnostics with experimental measurements indicating that PCS14 compressed well to a linear compression ratio of 2.5:1.
Laboratory simulation of space plasma phenomena*
Amatucci, B.; Tejero, E. M.; Ganguli, G.; Blackwell, D.; Enloe, C. L.; Gillman, E.; Walker, D.; Gatling, G.
2017-12-01
Laboratory devices, such as the Naval Research Laboratory's Space Physics Simulation Chamber, are large-scale experiments dedicated to the creation of large-volume plasmas with parameters realistically scaled to those found in various regions of the near-Earth space plasma environment. Such devices make valuable contributions to the understanding of space plasmas by investigating phenomena under carefully controlled, reproducible conditions, allowing for the validation of theoretical models being applied to space data. By working in collaboration with in situ experimentalists to create realistic conditions scaled to those found during the observations of interest, the microphysics responsible for the observed events can be investigated in detail not possible in space. To date, numerous investigations of phenomena such as plasma waves, wave-particle interactions, and particle energization have been successfully performed in the laboratory. In addition to investigations such as plasma wave and instability studies, the laboratory devices can also make valuable contributions to the development and testing of space plasma diagnostics. One example is the plasma impedance probe developed at NRL. Originally developed as a laboratory diagnostic, the sensor has now been flown on a sounding rocket, is included on a CubeSat experiment, and will be included on the DoD Space Test Program's STP-H6 experiment on the International Space Station. In this presentation, we will describe several examples of the laboratory investigation of space plasma waves and instabilities and diagnostic development. *This work supported by the NRL Base Program.
Simulation on solidification of an Al-Ni alloy under electromagnetic stirring
Directory of Open Access Journals (Sweden)
Sha Minghong
2012-08-01
Full Text Available The microstructure of Al-Ni alloy has a significant influence on its performance, while electromagnetic stirring is one of the most effective methods for control of solidification structure of Al alloy. To investigate the effect of electromagnetic stirring on the solidification of the ingot, the solidification of the Al-50Ni alloy in vacuum with electromagnetic stirring was described by numerical simulation in this paper; and a three dimensional mathematical model was established. The electromagnetic field was simulated by ANSYS software and the thermal-flow field was simulated by FLUENT software. The coupling between the electromagnetic field and the thermal-flow field was implemented by user-defined subroutines. It is found that the current intensity has significant influences on the fluid flow and the microstructure of the alloy. The simulation results agree well with the experimental results, and the optimum current intensity under the exprimental conditions is 80 A, while the frequency is 50 Hz.
Electromagnetic energy density and stress tensor in a warm plasma with finite flow velocity
International Nuclear Information System (INIS)
Choi, Cheong R.; Lee, Nam C.
2004-01-01
The expressions of the average of energy density and the average stress tensor of the electromagnetic field in a warm collisionless plasma moving with a finite velocity are obtained by using a microscopic method that uses the fluid description of plasma. The result contains terms involved with derivatives of the dielectric tensor with respect to the velocity, which explicitly represent the effects of the finite velocity of the medium. In the zero-velocity limit, the results reduce to the well-known expressions for a plasma at rest with temporal and spatial dispersion
Chabert, P.
2007-02-01
In plasma processing, capacitive discharges have classically been operated in the electrostatic regime, for which the excitation wavelength λ is much greater than the electrode radius, and the plasma skin depth δ is much greater than the electrode spacing. However, contemporary reactors are larger and excited at higher frequencies which leads to strong electromagnetic effects. This paper gives a review of the work that has recently been carried out to carefully model and diagnose these effects, which cause major uniformity problems in plasma processing for microelectronics and flat panel displays industries.
Scattering of electromagnetic waves by a nonuniform cylindrical plasma in the eikonal approximation
International Nuclear Information System (INIS)
Sharma, S.K.; Dasgupta, B.
1987-01-01
The scattering of a uniform plane electromagnetic wave from an inhomogeneous cylindrical plasma in the presence of an axial static magnetic field is treated in the eikonal approximation. A simple expression is presented for the scattering function for ordinary wave scattering. This expression is expected to be a good approximation at small angles and for refractive indices close to unity (ω 2 >> ω 2 sub(p)). In order to show the accuracy of the eikonal approximation numerical comparisons with the exact results are presented for the simple model of homogeneous plasma. Implications of the eikonal results in the plasma diagnostics are discussed. (author)
Numerical simulation of the plasma current quench following a disruptive energy loss
International Nuclear Information System (INIS)
Strickler, D.J.; Peng, Y.K.M.; Holmes, J.A.; Miller, J.B.; Rothe, K.E.
1983-11-01
The plasma electromagnetic interaction with poloidal field coils and nearby passive conductor loops during the current quench following a disruptive loss of plasma energy is simulated. By solving a differential/algebraic system consisting of a set of circuit equations (including the plasma circuit) coupled to a plasma energy balance equation and an equilibrium condition, the electromagnetic consequences of an abrupt thermal quench are observed. Limiters on the small and large major radium sides of the plasma are assumed to define the plasma cross section. The presence of good conductors near the plasma and a small initial distance (i.e., 5 to 10% of the plasma minor radius) between the plasma edge and an inboard limiter are shown to lead to long current decay times. For a plasma with an initial major radius R/sub o/ = 4.3 m, aspect ratio A = 3.6, and current I/sub P/ = 4.0 MA, introducing nearby passive conductors lengthens the current decay from milliseconds to hundreds of milliseconds
Some preliminary views of plasma interaction: electromagnetic-launch systems
International Nuclear Information System (INIS)
Buckingham, A.C.; Hawke, R.S.
1982-01-01
This discussion outlines a few areas of fundamental research which appear vital for progress in developing advanced propulsion concepts using dc railgun thrusters. We have placed emphasis on the following: (1) dense plasma and high current density influences on changes in microstructure and properties of conventional rail conductors such as Cu, Al, and W alloys or composites; (2) the influences described in (1) on more advanced high temperature, microstrain resistant, materials such as amorphous tungsten; (3) location, description and temporal evolution of current, magnetic field, and losses during intense plasma-current field interactions with conductors; and (4) composite materials and sequentially sectioned structures for more efficient EM dc launcher configuration
Ruhai Li; Chaoshun Li; Xuanlin Peng; Wei Wei
2017-01-01
The electromagnetic vibration caused by electromagnetic force on the stator has threatened large hydro generators operating safely and stably. At the Zhexi hydropower station, the hydro generator was beset by electromagnetic vibration for a long time. Therefore, the paper provided a new method to help to find the vibration source and detect the hydro generator fault, through the combination of simulation and experiments. In this paper, the 3D stator pack structure model and the 2D hydro gener...
Spectrum of harmonic emission by inhomogeneous plasma in intense electromagnetic wave
International Nuclear Information System (INIS)
Kovalev, V.F.; Pustovalov, V.V.
1989-01-01
The spectrum and angular distribution of the harmonics of arbitrary index emitted by a cold, inhomogeneous electron plasma subjected to a p-polarized electromagnetic wave have been studied analytically. The results are shown in graphical form. The intensity of the wave was varied over a wide range. At energy flux densities of the electromagnetic wave at which the inverse effect of the higher harmonics on the lower harmonics becomes appreciable, it becomes possible to observe a decay of the absolute value of the complex amplitude of a harmonic with increasing harmonic index in vacuum which is substantially slower than that predicted by the theory for a weak nonlinearity
Plasma temperature measurements in disruption simulated experiment
Energy Technology Data Exchange (ETDEWEB)
Arkhipov, N.I. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Bakhtin, V.P. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Toporkov, D.A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Vasenin, S.G. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Wurz, H. [Kernforschungszentrum Karlsruhe, INR (Germany); Zhitlukhin, A.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation)
1995-12-31
Results are reported of experiments to measure the temporal and spatial distributions of a temperature and radiation of a near surface plasma cloud appearing in the disruption simulated experiments. These measurements are needed to verificate the different numerical models of vapor shielding layer which appears to arise near the divertor plates surface and prevents them from the bulk of the incoming energy. Experiments with graphite and tungsten samples were carried out at the 2MK-200 plasma facility. Long CUSP trap was used as a source of high temperature deuterium plasma with a power density W = 10 MW/cm{sup 2} and time duration t = 20 mcs. Laser scattering, space and time resolved soft x-ray spectroscopy was employed to measure the plasma cloud temperature and radiation. The different behaviour of shielding layer parameters was shown for a graphite and tungsten samples. For a tungsten the sharp boundary existed between the incoming deuterium plasma and the thin layer of ablated material plasma and the strong gradient of electron temperature took place in this zone. For a graphite this boundary was broadened at the distance and the main part of the screening layer consisted of the mixture of the incoming deuterium and ablated carbon plasma. (orig.).
Simulation of plasma erosion opening switches
International Nuclear Information System (INIS)
Mason, R.J.; Jones, M.E.
1988-01-01
Recent progress in the modeling of Plasma Erosion Opening Switches is reviewed, and new results from both fluid and particle simulation compared. Three-fluid simulations with the ANTHEM code for switches on the NRL GAMBLE I machine and SNL PBFA II machine have shown strong dependence of the opening dynamics on the anode structure, the threshold for electron emission, on the possible presence of anomalous resistivity, and on advection of the magnetic field with cathode emitted electrons. Simulations with the implicit particle-in-cell code ISIS confirm these observations, but manifest broader current channels---in better agreement with GAMBLE I experimental results. 7 refs., 3 figs
Branch companion modeling for diverse simulation of electromagnetic and electromechanical transients
Energy Technology Data Exchange (ETDEWEB)
Shintaku, Rachel; Strunz, Kai [SESAME Laboratory, Department of Electrical Engineering, University of Washington, Seattle (United States)
2007-09-15
Simulators of the Electromagnetic Transients Program (EMTP) type are widely used for the study of high-frequency transients in power electric systems. For the study of electromechanical transients, where the main interest is to focus only on deviations from the ac waveform, the EMTP approach is not efficient. In this paper, a branch companion model that is suitable for both electromagnetic and electromechanical transients simulation is proposed. It processes analytic signals whose Fourier spectrum can be shifted in accordance with the objective of the study. The proposed method opens the way for a unified description of electromagnetic and electromechanical transients simulation. (author)
Bow Wave from Ultraintense Electromagnetic Pulses in Plasmas
International Nuclear Information System (INIS)
Esirkepov, T. Zh.; Bulanov, S. V.; Kato, Y.
2008-01-01
We show a new effect of the bow-wave excitation by an intense short laser pulse propagating in underdense plasma. Because of spreading of the laser pulse energy in transverse direction, the bow wave causes a large-scale transverse modulation of the electron density. This can significantly increase the electric potential of the wake wave since the wake wave is generated in the region much wider than the laser pulse waist
Fast simulation of electromagnetic showers in the ATLAS calorimeter Frozen showers
Barberio, E; Butler, B; Cheung, S L; Dell'Acqua, A; Di Simone, A; Ehrenfeld, E; Gallas, M V; Glazov, A; Marshall, Z; Mueller, J; Plačakyte, R; Rimoldi, A; Savard, P; Tsulaia, V; Waugh, A; Young, C C
2009-01-01
One of the most time consuming process simulating pp interactions in the ATLAS detector at LHC is the simulation of electromagnetic showers in the calorimeter. In order to speed up the event simulation several parametrisation methods are available in ATLAS. In this paper we present a short description of a frozen shower technique, together with some recent benchmarks and comparison with full simulation.
Recent progress of Geant4 electromagnetic physics for calorimeter simulation
Incerti, S.; Ivanchenko, V.; Novak, M.
2018-02-01
We report on recent progress in the Geant4 electromagnetic (EM) physics sub-packages. New interfaces and models introduced recently in Geant4 10.3 are already used in LHC applications and may be useful for any type of simulation. Additional developments for EM physics are available with the new public version Geant4 10.4 (December, 2017). Important developments for calorimetry applications were carried out for the modeling of single and multiple scattering of charged particles. Corrections to scattering of positrons and to sampling of displacement have recently been added to the Geant4 default Urban model. The fully theory-based Goudsmit-Saunderson (GS) model for electron/positron multiple scattering was recently reviewed and a new improved version is available in Geant4 10.4. For testing purposes for novel calorimeters we provide a configuration of electron scattering based on the GS model or on the single scattering model (SS) instead of the Urban model. In addition, the GS model with Mott corrections enabled is included in the option4 EM physics constructor. This EM configuration provides the most accurate results for scattering of electrons and positrons.
Grishin, Yu. M.; Long, Miao
2017-11-01
The results of numerical simulation of plasma flow in the channel of technological radio frequency (RF) plasma torch with three coils and frequency at 3 MHz are presented. The mixture of argon with hydrogen is considered as the working gas at a variation of hydrogen volume fraction α from 0 to 10%. The distributions of electromagnetic fields and gas-dynamic parameters of the plasma flow are calculated. It is shown that when the amplitude of discharge current exceeds the critical value Jcr (depends on α), the regime of plasma flow transforms from the potential to vortical regime, in which a toroidal vortex is formed before or in the inductor zone. The dependence of the values of the critical current Jcr on the volume concentration of hydrogen α is established. The influences of volume fraction α and discharge current Jcoil on the intensities and the position of the vortex center are determined.
International Nuclear Information System (INIS)
Roderick, N.F.; Hussey, T.W.; Faehl, R.J.; Boyd, R.W.
1978-01-01
Two-dimensional (r-z) magnetohydrodynamic simulations of the electromagnetic implosion of metallic foil plasmas show, for certain initial configurations, a tendency to develop large-amplitude perturbations characteristic of the hydromagnetic Rayleigh-Taylor instability. These perturbations develop at the plasma magnetic field interface for plasma configurations where the density gradient scale length, the characteristic dimension for the instability, is short. The effects on the plasma dynamics of the implosion will be discussed for several initial foil configurations. In general, the growth rates and linear mode structure are found to be influenced by the plasma shell thickness and density gradient scale length, in agreement with theory. The most destructive modes are found to be those with wavelengths of the order of the plasma shell thickness
International Nuclear Information System (INIS)
Isanin, A.V.; Kamenets, F.F.; Bulanov, S.S.; Pegoraro, F.
2005-01-01
During the interaction of a low-frequency relativistic soliton with the electron density modulations of a wake plasma wave, part of the electromagnetic energy of the soliton is reflected in the form of an extremely short and ultraintense electromagnetic pulse. We calculate the spectra of the reflected and of the transmitted electromagnetic pulses analytically. The reflected wave has the form of a single cycle attosecond pulse
Simulations of JET pellet fuelled ITB plasmas
Garzotti, L.; Garbet, X.; Thyagaraja, A.; de Baar, M. R.; Frigione, D.; Mantica, P.; Parail, V.; Pégourié, B.; Zabeo, L.; EFDA contributors, JET
2006-01-01
Experiments were performed on JET where high-density plasmas with an internal transport barrier (ITB) were created by means of combined use of lower hybrid current drive (LHCD) and pellet injection before the barrier formation. Attempts were also made to use pellets to fuel the plasma and to sustain the density during the ITB phase. It was found that shallow pellets ablating in the region r/a >= 0.8 and far from the foot of the barrier did not destroy the ITB, whereas deeper pellets penetrating up to 0.6 CUTIE, a global electromagnetic fluid turbulence code. The results show that for the shallow pellet case all codes reproduce the general features of the experiment, whereas for the deep pellet case, there are differences in the degree of agreement between the different codes and the experiment. Runs performed varying the pellet penetration depth indicate that not only the pellet penetration, but also the barrier strength plays a key role in the dynamics of the pellet-ITB interaction.
Modulation of a compressional electromagnetic wave in a magnetized electron-positron quantum plasma
Amin, M. R.
2015-09-01
Amplitude modulation of a compressional electromagnetic wave in a strongly magnetized electron-positron pair plasma is considered in the quantum magnetohydrodynamic regime. The important ingredients of this study are the inclusion of the external strong magnetic field, Fermi quantum degeneracy pressure, particle exchange potential, quantum diffraction effects via the Bohm potential, and dissipative effect due to collision of the charged carriers. A modified-nonlinear Schödinger equation is developed for the compressional magnetic field of the electromagnetic wave by employing the standard reductive perturbation technique. The linear and nonlinear dispersions of the electromagnetic wave are discussed in detail. For some parameter ranges, relevant to dense astrophysical objects such as the outer layers of white dwarfs, neutron stars, and magnetars, etc., it is found that the compressional electromagnetic wave is modulationally unstable and propagates as a dissipated electromagnetic wave. It is also found that the quantum effects due to the particle exchange potential and the Bohm potential are negligibly small in comparison to the effects of the Fermi quantum degeneracy pressure. The numerical results on the growth rate of the modulation instability is also presented.
Time-stepped & discrete-event simulations of electromagnetic propulsion systems, Phase I
National Aeronautics and Space Administration — We propose to develop a new generation of electromagnetic simulation codes with mixed resolution modeling capabilities. The need for such codes arises in many fields...
Atomic configuration average simulations for plasma spectroscopy
International Nuclear Information System (INIS)
Kilcrease, D.P.; Abdallah, J. Jr.; Keady, J.J.; Clark, R.E.H.
1993-01-01
Configuration average atomic physics based on Hartree-Fock methods and an unresolved transition array (UTA) simulation theory are combined to provide a computationally efficient approach for calculating the spectral properties of plasmas involving complex ions. The UTA theory gives an overall representation for the many lines associated with a radiative transition from one configuration to another without calculating the fine structure in full detail. All of the atomic quantities required for synthesis of the spectrum are calculated in the same approximation and used to generate the parameters required for representation of each UTA, the populations of the various atomic states, and the oscillator strengths. We use this method to simulate the transmission of x-rays through an aluminium plasma. (author)
Stability of strong electromagnetic waves in overdense plasmas
Energy Technology Data Exchange (ETDEWEB)
Romeiras, F.J. (Instituto Superior Tecnico, Lisbon (Portugal). Centro de Electrodinamica)
1982-04-01
The stability against small perturbations of a class of exact wave solutions of the equations that describe an unmagnetized relativistic cold electron plasma is considered. The main feature of these nonlinear waves is a transverse circularly polarized electric field with periodic amplitude modulation in the longitudinal direction. Floquet's theory of linear differential equations with periodic coefficients is used to solve the perturbation equations and obtain the instability growth rates. Both an approximate solution for small modulation depth and a numerical treatment for arbitrary depth are presented. It is shown that the well-known small-wavenumber instability of the purely transverse circularly polarized waves of constant amplitude is reduced as the modulation depth increases from zero to its maximum allowed value.
Yao, Bo; Li, Xiaoping; Shi, Lei; Liu, Yanming; Lei, Fan; Zhu, Congying
2017-10-01
An experiment on the propagation of electromagnetic (EM) signals in continuous time-varying plasma is designed to establish the nonlinear mirror between electron density and transmission coefficient. The nonlinearity is confirmed from the theoretical and experimental results. The amplitude and phase can be considered nonlinear functions of electron density when the complex interaction between plasma and EM waves is ignored. Results show that amplitude and phase distributions are asymmetrical when electron density follows symmetric distribution. The skewness of amplitude is positive, whereas the skewness of phase is negative. The nonlinear degree is closely related to the ratio of plasma frequency to the incident wave frequency and the range of electron density. The conclusions are crucial to the modeling of plasma sheath channels and understanding the blackout problem.
Analog modeling of splitting the envelope of an electromagnetic pulse reflected from a plasma layer
International Nuclear Information System (INIS)
Bakunov, M.I.; Rogozhin, I.Yu.
1997-01-01
By means of a simple radio engineering model, an experimental study is carried out of the effect of the strong deformation of the envelope of a quasimonochromatic electromagnetic pulse reflected from a thin plasma layer placed on the surface of an ideal conductor. This deformation is considered under the conditions of the plasma resonance in the plasma layer and when the thickness of the layer is less then the wavelength of the incident radiation. It is shown that the pulse whose initial profile is Gaussian, after the reflection, is separated (entirely of partially) into two pulses with amplitudes that can be controlled by means of varying the parameters of the incident pulse and plasma layer
Analysis of Simulated Aircraft Lightning Strikes and Their Electromagnetic Effects
National Research Council Canada - National Science Library
Gruden, James
2001-01-01
To survive the intense electromagnetic fields associated with a lightning strike, proper design of aircraft electrical control systems requires knowledge of the transient current pulse associated with a lightning strike...
DEFF Research Database (Denmark)
This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis......, material characterization, electromagnetic properties of plasma, analysis and applications of periodic structures and waveguide components, etc....
Directory of Open Access Journals (Sweden)
Ruhai Li
2017-12-01
Full Text Available The electromagnetic vibration caused by electromagnetic force on the stator has threatened large hydro generators operating safely and stably. At the Zhexi hydropower station, the hydro generator was beset by electromagnetic vibration for a long time. Therefore, the paper provided a new method to help to find the vibration source and detect the hydro generator fault, through the combination of simulation and experiments. In this paper, the 3D stator pack structure model and the 2D hydro generator electromagnetic models under rotor eccentricity and rotor ellipse deformation conditions were built. Then, electromagnetism simulations were conducted to study the characteristics of the electromagnetic flux and electromagnetic force under different conditions by using the finite element method (FEM. Lastly, the vibration testing experiments and harmonic response simulations of stator frame were performed to present the characteristics of vibration distribution in frequency conditions. The simulation results were compared with the generator measured data to try to find out the main vibration source and guide the overhaul.
Numerical simulations of electromagnetic scattering by Solar system objects
Dlugach, Janna M.
2016-11-01
Having been profoundly stimulated by the seminal work of Viktor V. Sobolev, I have been involved in multi-decadal research in the fields of radiative transfer, electromagnetic scattering by morphologically complex particles and particulate media, and planetary remote sensing. Much of this research has been done in close collaboration with other "descendants" of Academician Sobolev. This tutorial paper gives a representative overview of the results of extensive numerical simulations (in the vast majority carried out in collaboration with Michael Mishchenko) used to analyze remote-sensing observations of Solar system objects and based on highly accurate methods of the radiative transfer theory and direct computer solvers of the Maxwell equations. Using the atmosphere of Jupiter as a proving ground and performing T-matrix and radiative-transfer calculations helps demonstrate the strong effect of aerosol-particle shapes on the accuracy of remote-sensing retrievals. I then discuss the application of the T-matrix method, a numerically exact solution of the vector radiative transfer equation, and the theory of coherent backscattering to an analysis of polarimetric radar observations of Saturn's rings. Numerical modeling performed by using the superposition T-matrix method in application to cometary dust in the form of aggregates serves to reproduce the results of polarimetric observations of the distant comet C/2010 S1. On the basis of direct computer solutions of the Maxwell equations, it is demonstrated that all backscattering effects predicted by the low-density theories of radiative transfer and coherent backscattering can also be identified for media with volume packing densities typically encountered in natural and artificial environments. This result implies that spectacular opposition effects observed for some high-albedo atmoshereless Solar system bodies can be attributed to coherent backscattering of sunlight by regolith layers composed of microscopic particles.
International Nuclear Information System (INIS)
Sanchez-Arriaga, G.; Lefebvre, E.
2011-01-01
The dynamics of two-dimensional s-polarized solitary waves is investigated with the aid of particle-in-cell (PIC) simulations. Instead of the usual excitation of the waves with a laser pulse, the PIC code was directly initialized with the numerical solutions from the fluid plasma model. This technique allows the analysis of different scenarios including the theoretical problems of the solitary wave stability and their collision as well as features already measured during laser-plasma experiments such as the emission of electromagnetic bursts when the waves reach the plasma-vacuum interface, or their expansion on the ion time scale, usually named post-soliton evolution. Waves with a single density depression are stable whereas multihump solutions decay to several waves. Contrary to solitons, two waves always interact through a force that depends on their relative phases, their amplitudes, and the distance between them. On the other hand, the radiation pattern at the plasma-vacuum interface was characterized, and the evolution of the diameter of different waves was computed and compared with the ''snow plow'' model.
Electron cloud simulation of the ECR plasma
International Nuclear Information System (INIS)
Racz, R.; Biri, S.; Palinkas, J.
2011-01-01
Complete text of publication follows. The plasma of the Electron Cyclotron Resonance Ion Source (ECRIS) of ATOMKI is being continuously investigated by different diagnostic methods: using small-sized probes or taking X-ray and visible light photographs. In 2011 three articles were published by our team in a special edition of the IEEE Transactions on Plasma Science (Special Issue on Images in Plasma Science) describing our X-ray and visible light measurements and plasma modeling and simulating studies. Simulation is in many cases the base for the analysis of the photographs. The outcomes of the X-ray and visible light experiments were presented already in earlier issues of the Atomki Annual Report, therefore in this year we concentrate on the results of the simulating studies. The spatial distribution of the three main electron components (cold, warm and hot electron clouds) of the ECR plasmas was simulated by TrapCAD code. TrapCAD is a 'limited' plasma simulation code. The spatial and energy evolution of a large number of electrons can be realistically followed; however, these particles are independent, and no particle interactions are included. In ECRISs, the magnetic trap confines the electrons which keep together the ion component by their space charge. The electrons gain high energies while the ions remain very cold throughout the whole process. Thus, the spatial and energy simulation of the electron component gives much important and numerical information even for the ions. The electron components of ECRISs can artificially be grouped into three populations: cold, warm, and hot electrons. Cold electrons (1-200 eV) have not been heated by the microwave; they are mainly responsible for the visible light emission of the plasma. The energized warm electrons (several kiloelectronvolts) are able to ionize atoms and ions and they are mainly responsible for the characteristic Xray photons emitted by the plasma. Electrons having much higher energy than necessary for
MAGNETIC NULL POINTS IN KINETIC SIMULATIONS OF SPACE PLASMAS
International Nuclear Information System (INIS)
Olshevsky, Vyacheslav; Innocenti, Maria Elena; Cazzola, Emanuele; Lapenta, Giovanni; Deca, Jan; Divin, Andrey; Peng, Ivy Bo; Markidis, Stefano
2016-01-01
We present a systematic attempt to study magnetic null points and the associated magnetic energy conversion in kinetic particle-in-cell simulations of various plasma configurations. We address three-dimensional simulations performed with the semi-implicit kinetic electromagnetic code iPic3D in different setups: variations of a Harris current sheet, dipolar and quadrupolar magnetospheres interacting with the solar wind, and a relaxing turbulent configuration with multiple null points. Spiral nulls are more likely created in space plasmas: in all our simulations except lunar magnetic anomaly (LMA) and quadrupolar mini-magnetosphere the number of spiral nulls prevails over the number of radial nulls by a factor of 3–9. We show that often magnetic nulls do not indicate the regions of intensive energy dissipation. Energy dissipation events caused by topological bifurcations at radial nulls are rather rare and short-lived. The so-called X-lines formed by the radial nulls in the Harris current sheet and LMA simulations are rather stable and do not exhibit any energy dissipation. Energy dissipation is more powerful in the vicinity of spiral nulls enclosed by magnetic flux ropes with strong currents at their axes (their cross sections resemble 2D magnetic islands). These null lines reminiscent of Z-pinches efficiently dissipate magnetic energy due to secondary instabilities such as the two-stream or kinking instability, accompanied by changes in magnetic topology. Current enhancements accompanied by spiral nulls may signal magnetic energy conversion sites in the observational data
Gao, Xiatian; Wang, Xiaogang; Jiang, Binhao
2017-10-01
UPSF (Universal Plasma Simulation Framework) is a new plasma simulation code designed for maximum flexibility by using edge-cutting techniques supported by C++17 standard. Through use of metaprogramming technique, UPSF provides arbitrary dimensional data structures and methods to support various kinds of plasma simulation models, like, Vlasov, particle in cell (PIC), fluid, Fokker-Planck, and their variants and hybrid methods. Through C++ metaprogramming technique, a single code can be used to arbitrary dimensional systems with no loss of performance. UPSF can also automatically parallelize the distributed data structure and accelerate matrix and tensor operations by BLAS. A three-dimensional particle in cell code is developed based on UPSF. Two test cases, Landau damping and Weibel instability for electrostatic and electromagnetic situation respectively, are presented to show the validation and performance of the UPSF code.
Comparisons of dense-plasma-focus kinetic simulations with experimental measurements
Energy Technology Data Exchange (ETDEWEB)
Schmidt, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Link, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Welch, D. [Voss Scientific, Inc., Albuquerque, NM (United States); Ellsworth, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Falabella, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tang, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2014-06-01
Dense-plasma-focus (DPF) Z-pinch devices are sources of copious high-energy electrons and ions, x rays, and neutrons. The mechanisms through which these physically simple devices generate such high-energy beams in a relatively short distance are not fully understood and past optimization efforts of these devices have been largely empirical. Previously we reported on fully kinetic simulations of a DPF and compared them with hybrid and fluid simulations of the same device. Here we present detailed comparisons between fully kinetic simulations and experimental data on a 1.2 kJ DPF with two electrode geometries, including neutron yield and ion beam energy distributions. A more intensive third calculation is presented which examines the effects of a fully detailed pulsed power driver model. We also compare simulated electromagnetic fluctuations with direct measurement of radiofrequency electromagnetic fluctuations in a DPF plasma. These comparisons indicate that the fully kinetic model captures the essential physics of these plasmas with high fidelity, and provide further evidence that anomalous resistivity in the plasma arises due to a kinetic instability near the lower hybrid frequency.
Nonlinear electromagnetic perturbations in a degenerate ultrarelativistic electron-positron plasma.
El-Taibany, W F; Mamun, A A
2012-02-01
Nonlinear propagation of fast and slow magnetosonic perturbation modes in an ultrarelativistic, ultracold, degenerate (extremely dense) electron positron (EP) plasma (containing ultrarelativistic, ultracold, degenerate electron and positron fluids) has been investigated by the reductive perturbation method. The Alfvén wave velocity is modified due to the presence of the enthalpy correction in the fluid equations of motion. The degenerate EP plasma system (under consideration) supports the Korteweg-de Vries (KdV) solitons, which are associated with either fast or slow magnetosonic perturbation modes. It is found that the ultrarelativistic model leads to compressive (rarefactive) electromagnetic solitons corresponding to the fast (slow) wave mode. There are certain critical angles, θ(c), at which no soliton solution is found corresponding to the fast wave mode. For the slow mode, the magnetic-field intensity affects both the soliton amplitude and width. It is also illustrated that the basic features of the electromagnetic solitary structures, which are found to exist in such a degenerate EP plasma, are significantly modified by the effects of enthalpy correction, electron and positron degeneracy, magnetic-field strength, and the relativistic effect. The applications of the results in a pair-plasma medium, which occurs in many astrophysical objects (e.g., pulsars, white dwarfs, and neutron stars) are briefly discussed.
Simulation models for computational plasma physics: Concluding report
International Nuclear Information System (INIS)
Hewett, D.W.
1994-01-01
In this project, the authors enhanced their ability to numerically simulate bounded plasmas that are dominated by low-frequency electric and magnetic fields. They moved towards this goal in several ways; they are now in a position to play significant roles in the modeling of low-frequency electromagnetic plasmas in several new industrial applications. They have significantly increased their facility with the computational methods invented to solve the low frequency limit of Maxwell's equations (DiPeso, Hewett, accepted, J. Comp. Phys., 1993). This low frequency model is called the Streamlined Darwin Field model (SDF, Hewett, Larson, and Doss, J. Comp. Phys., 1992) has now been implemented in a fully non-neutral SDF code BEAGLE (Larson, Ph.D. dissertation, 1993) and has further extended to the quasi-neutral limit (DiPeso, Hewett, Comp. Phys. Comm., 1993). In addition, they have resurrected the quasi-neutral, zero-electron-inertia model (ZMR) and began the task of incorporating internal boundary conditions into this model that have the flexibility of those in GYMNOS, a magnetostatic code now used in ion source work (Hewett, Chen, ICF Quarterly Report, July--September, 1993). Finally, near the end of this project, they invented a new type of banded matrix solver that can be implemented on a massively parallel computer -- thus opening the door for the use of all their ADI schemes on these new computer architecture's (Mattor, Williams, Hewett, submitted to Parallel Computing, 1993)
Simulation of plasma double-layer structures
International Nuclear Information System (INIS)
Borovsky, J.E.; Joyce, G.
1982-01-01
Electrostatic plasma double layers are numerically simulated by means of a magnetized 2 1/2-dimensional particle-in-cell method. The investigation of planar double layers indicates that these one-dimensional potential structures are susceptible to periodic disruption by instabilities in the low-potential plasmas. Only a slight increase in the double-layer thickness with an increase in its obliqueness to the magnetic field is observed. Weak magnetization results in the double-layer electric-field alignment of accelerated particles and strong magnetization results in their magnetic-field alignment. The numerial simulations of spatially periodic two-dimensional double layers also exhibit cyclical instability. A morphological invariance in two-dimensional double layers with respect to the degree of magnetization implies that the potential structures scale with Debye lengths rather than with gyroradii. Electron-beam excited electrostatic electron-cyclotron waves and (ion-beam driven) solitary waves are present in the plasmas adjacent to the double layers
Scattering of electromagnetic waves by an non-uniform cylindrical plasma
International Nuclear Information System (INIS)
Faugeras, P.E.
1966-12-01
The problem of the scattering of plane electromagnetic waves from a non-uniform, cylindrically symmetrical plasma is solved analytically, by a self-consistent field method, for a wave with the electric field parallel to the cylinder axis. Numerical results for the diffracted field are plotted for interesting ranges of the parameters involved: diameter, density on the axis, radial profile of the density, and collision frequencies. The case where the incident field is cylindric (waves surfaces parallel to the cylinder axis) is examined - this permits to connect theoretical calculations and experimental diffraction patterns, and also to explain the diffraction effects observed in a classical microwave interferometry experiment. These results, and the possibility of measuring exactly the diffracted field (showed by experiments with dielectric and metallic rods) lead to a new plasma diagnostic method, based on the diffraction, which has no theoretical limitations and it usable when the classical free-space wave methods are not (plasma diameter lower than 10 wave lengths). The feasibility of this method is tested with a plasma at atmospheric pressure and a 2 mm incident wavelength. The plasma is obtained by the laminar flow of a plasma torch, with a working gas (He or Ar) seeded by potassium (density continuously variable between 10 11 and 10 15 e/cm 3 . Some diffraction patterns by this plasma and for various incident waves, are also given and explained with theoretical calculations. (author) [fr
International Nuclear Information System (INIS)
Jamali, J.; Aghajafari, R.; Moini, R.; Sadeghi, H.
2002-01-01
A time-domain approach is presented to calculate electromagnetic fields inside a large Electromagnetic Pulse (EMP) simulator. This type of EMP simulator is used for studying the effect of electromagnetic pulses on electrical apparatus in various structures such as vehicles, a reoplanes, etc. The simulator consists of three planar transmission lines. To solve the problem, we first model the metallic structure of the simulator as a grid of conducting wires. The numerical solution of the governing electric field integral equation is then obtained using the method of moments in time domain. To demonstrate the accuracy of the model, we consider a typical EMP simulator. The comparison of our results with those obtained experimentally in the literature validates the model introduced in this paper
Energy Technology Data Exchange (ETDEWEB)
Assous, F.; Degond, P.; Segre, J. [CEA Limeil, 94 - Villeneuve-Saint-Georges (France); Degond, P. [MIP, UFR MIG, UPS, 31 - Toulouse (France)
1997-10-01
The aim of this paper is to present a new explicit time scheme for electromagnetic particle simulations. The main property of this new scheme, which depends on a parameter, is to reduce and in some cases to suppress numerical instabilities that can appear in this context, and are widely described in the literature. Other numerical properties are also investigated, and a numerical example is finally given to illustrate our purpose. This scheme is expected to be useful in the field of plasma modelling. (authors) 16 refs.
Grant, Ian S
1990-01-01
The Manchester Physics Series General Editors: D. J. Sandiford; F. Mandl; A. C. Phillips Department of Physics and Astronomy, University of Manchester Properties of Matter B. H. Flowers and E. Mendoza Optics Second Edition F. G. Smith and J. H. Thomson Statistical Physics Second Edition F. Mandl Electromagnetism Second Edition I. S. Grant and W. R. Phillips Statistics R. J. Barlow Solid State Physics Second Edition J. R. Hook and H. E. Hall Quantum Mechanics F. Mandl Particle Physics Second Edition B. R. Martin and G. Shaw the Physics of Stars Second Edition A. C. Phillips Computing for Scient
Nonlinear electromagnetic fields in 0.5 MHz inductively coupled plasmas
DEFF Research Database (Denmark)
Ostrikov, K.N.; Tsakadze, E.L.; Xu, S.
2003-01-01
Radial profiles of magnetic fields in the electrostatic (E) and electromagnetic (H) modes of low-frequency (similar to500 kHz) inductively coupled plasmas have been measured using miniature magnetic probes. In the low-power (similar to170 W) E-mode, the magnetic field pattern is purely linear......, with the fundamental frequency harmonics only. After transition to higher-power (similar to1130 W) H-mode, the second-harmonic nonlinear azimuthal magnetic field B-phi(2omega) that is in 4-6 times larger than the fundamental frequency component B-phi(omega), has been observed. A simplified plasma fluid model...... explaining the generation of the second harmonics of the azimuthal magnetic field in the plasma source is proposed. The nonlinear second harmonic poloidal (r-z) rf current generating the azimuthal magnetic field B-phi(2omega) is attributed to nonlinear interactions between the fundamental frequency radial...
International Nuclear Information System (INIS)
Glasser, A.H.; Swanson, D.G.; Wersinger, J.M.
1982-01-01
The continuation of a program of theoretical studies of the heating of toroidal plasmas with radio frequency (RF) electromagnetic radiation is proposed. Funding for this project first began on September 3, 1981, and will expire on April 2, 1982. A summary of the principal accomplishments of the first five months of the project is presented. These include the acquisition of computer terminals and modems, the implementation of existing codes on the MFECC C Cray Computer, the extension of the LHTOR lower hybrid toroidal ray tracing code to the full electromagnetic dispersion relation, the implementation of graphic output from the code, the beginning of extensive parameter studies, the beginning of an analytical treatment of the mode conversion layer associated with singular harmonic absorption, and the introduction of a graduate student into the program
Spectral methods in numerical plasma simulation
International Nuclear Information System (INIS)
Coutsias, E.A.; Hansen, F.R.; Huld, T.; Knorr, G.; Lynov, J.P.
1989-01-01
An introduction is given to the use of spectral methods in numerical plasma simulation. As examples of the use of spectral methods, solutions to the two-dimensional Euler equations in both a simple, doubly periodic region, and on an annulus will be shown. In the first case, the solution is expanded in a two-dimensional Fourier series, while a Chebyshev-Fourier expansion is employed in the second case. A new, efficient algorithm for the solution of Poisson's equation on an annulus is introduced. Problems connected to aliasing and to short wavelength noise generated by gradient steepening are discussed. (orig.)
Spectral Methods in Numerical Plasma Simulation
DEFF Research Database (Denmark)
Coutsias, E.A.; Hansen, F.R.; Huld, T.
1989-01-01
in a two-dimensional Fourier series, while a Chebyshev-Fourier expansion is employed in the second case. A new, efficient algorithm for the solution of Poisson's equation on an annulus is introduced. Problems connected to aliasing and to short wavelength noise generated by gradient steepening are discussed.......An introduction is given to the use of spectral methods in numerical plasma simulation. As examples of the use of spectral methods, solutions to the two-dimensional Euler equations in both a simple, doubly periodic region, and on an annulus will be shown. In the first case, the solution is expanded...
Computational physics of plasma turbulence: CUTIE simulations
Energy Technology Data Exchange (ETDEWEB)
Thyagaraja, A.
1995-11-01
In this work, direct numerical simulations of two-fluid plasma turbulence using the CUTIE code developed at Culham are briefly described. It presents the formulation of the model, an outline of the solution methods employed and a set of results obtained for COMPASS-D-like conditions with the code. The calculations show the formation of self-organized coherent structures and the existence of ``meso-scale`` current and vorticity fluctuations in the presence of imposed toroidal flow and self-generated poloidal electric drifts. (author).
THE SIMULATION OF SCATTERING OF ELECTROMAGNETIC WAVES ON ANGULAR STRUCTURES.
Directory of Open Access Journals (Sweden)
P. A. Preobrazhensky
2017-02-01
Full Text Available The paper discusses the characteristics of scattering of electromagnetic waves on the angular diffraction structures. The solution of the problem is based on the method of integral equations. A comparative analysis of the scattering characteristics of structures with different shape is carried out.
Direct numerical simulations of two-fluid plasma turbulence
Energy Technology Data Exchange (ETDEWEB)
Thyagaraja, A.
1995-06-01
This report presents initial results on the direct numerical simulations of two-fluid plasma turbulence using the CUTIE code developed at Culham. This code seeks to simulate low frequency ({omega} {approx} {omega}{sub *} << {omega}{sub ci}), relatively long wavelength (k{sub perpendicular} {sub to}{rho}{sub i} << 1;m, n up to 20-30) drift-like fluctuations. It employs a periodic cylinder ({tau},{theta},{phi} {identical_to} z/R) geometry and takes advantage of tokamak ordering (ie a/R << 1, B{sub {theta}}/B{sub z} << 1, {beta} << 1) in appropriate circumstances. Quasi-neutrality is assumed and standard two-fluid/Maxwell equations are solved for the seven variables, n{sub e}, T{sub e}, T{sub i}, V {sub parallel} {sub to}, {Phi}, {Psi} and {Omega} taking account of the appropriate sources and relevant transport co-efficients. The system is fully nonlinear, electromagnetic and takes account of neoclassical/classical `parallel` effects. (author).
International Nuclear Information System (INIS)
Gao Chunxia; Wang Lianghou
2005-01-01
The characteristics of different types of PML were analyzed and the convolutional PML was chosen to truncate the open boundaries in numerical simulation of nuclear electromagnetic pulse from air explosions. On the basis of the split-field PML and the plane-wave solution of electromagnetic field in free space, the unsplit-field PML was constructed. By applying the convolutional theorem of Fourier transform, the discrete iterative equations of electromagnetic field components were presented in the CPML media under the two-dimension prolate-spheroidal coordinate system. The numerical results indicate that the method of CPML can largely decrease calculation errors of boundary fields. (authors)
International Nuclear Information System (INIS)
Nonaka, S.
1992-01-01
Recently, large-area plasma production has been tested by means of a 13.56 MHz radio-frequency (RF) discharge between a pair of large-area planar electrodes, approximately 0.5 m x 1.4 m, as one of the semiconductor technologies for fabrication of large-area amorphous silicon solar cells in the ''Sunshine Project'' of the Agency of Industrial Science and Technology in Japan. We also confirmed long plasma production between a pair of long electrodes. In this paper, normal electromagnetic (EM) waves propagating in a region between a planar waveguide with one plasma and two dielectric layers are analyzed in order to study the feasibility of large-area plasma productions by EM wave-discharges between a pair of large-area RF electrodes larger than the half-wavelength of RF wave. In conclusion, plasmas higher than an electron plasma frequency will be produced by an odd TMoo surface mode. (author) 4 refs., 3 figs
Collective scattering of electromagnetic waves and cross-B plasma diffusion
International Nuclear Information System (INIS)
Gresillon, D.; Cabrit, B.; Truc, A.
1992-01-01
Magnetized plasmas occuring in nature as well as in fusion laboratories are oftenly irregularly shaked by magnetic field fluctuations. The so-called ''coherent scattering'' of electromagnetic wave from nonuniform, irregularly moving plasmas is investigated in the case where the scattering wavelength is large compared to the Debye length, but of the order of the irregularities correlation length. The scattered signal frequency spectrum is shown to be a transform of the plasma motion statistical characteristics. When the scattering wavelength is larger than the plasma motion correlation length, the frequency spectrum is shown to be of a lorentzian shape, with a frequency width that provides a direct measurement of the cross-B particle diffusion coefficient. This is illustrated by two series of recently obtained experimental results: radar coherent backscattering observations of the auroral plasma, and far infrared scattering from tokamak fusion plasma. Radar coherent backscattering shows the transition from Gauss to Lorentz scattered frequency spectra. In infrared Laser coherent scattering experiments from the Tore-Supra tokamak, a particular frequency line is observed to present a Lorentzian shape, that directly provides an electron cross-field diffusion coefficient. This diffusion coefficient agrees with the electron heat conductivity coefficient that is obtained from the observation of temperature profiles and energy balance. (Author)
Particle-in-cell simulations of plasma accelerators and electron-neutral collisions
Directory of Open Access Journals (Sweden)
David L. Bruhwiler
2001-10-01
Full Text Available We present 2D simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented particle-in-cell code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low \\(∼10^{16} W/cm^{2}\\ and high \\(∼10^{18} W/cm^{2}\\ peak intensity laser pulses are conducted in slab geometry, showing agreement with theory and fluid simulations. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications to XOOPIC required by this work, and summarize the issues relevant to modeling relativistic electron-neutral collisions in a particle-in-cell code.
High-Fidelity Simulations of Electromagnetic Propagation and RF Communication Systems
2017-05-01
Propagation and RF Communication Systems T53 Final Report Samuel S. Streeter, Daniel J. Breton, and Michele L. Maxson U.S. Army Engineer Research...Electromagnetic U.S. Army Engineer Research and Development Center Finite-Difference Time-Domain Geographic Information System Graphics Processing Unit...ER D C TR -1 7- 2 Military Engineering Applied Research High-Fidelity Simulations of Electromagnetic Propagation and RF Communication
Design and numerical simulation of the electromagnetic field of linear anode layer ion source
International Nuclear Information System (INIS)
Wang Lisheng; Tang Deli; Cheng Changming
2006-01-01
The principle of anode layer ion source for etching, pre-cleaning and ion beam assisted deposition was described. The influence of the magnetic field on the performance of anode layer ion source was analyzed. Design of the magnetic loop for the linear anode layer ion source was given. The electromagnetic field distribution of the ion source was simulated by means of ANSYS code and the simulation results were in agreement with experimental ones. The numerical simulation results of the electromagnetic field are useful for improving the anode layer ion source. (authors)
International Nuclear Information System (INIS)
Arzate P, N.
1994-01-01
Based on the fundamental theory of cylindrical waveguides and resonant cavities, the main characteristic parameters of the microwave plasma source reported in [1] are calculated. The absorption coefficient of an electromagnetic wave which is excited in H 11 mode in a cylindrical waveguide that contains a cold, inhomogeneous and magnetized plasma column is determined by using the perturbative method describe in [2]. In similar way, due to the presence of the plasma column, the shifts of the resonant frequency and of the inverse of the quality of a cylindrical resonant cavity where a TE 111 mode is oscilating are obtained. Finally, based on the linear theory, an analysis of the penetration of electromagnetic fields in a semi-bounded plasma and a plasma layer is done. The reflexion, transmission and absorption coefficients of H waves for the cases of an isotropic homogeneous and weak inhomogeneous plasma are calculated. (Author)
Kinetic Simulations of Dense Plasma Focus Breakdown
Schmidt, A.; Higginson, D. P.; Jiang, S.; Link, A.; Povilus, A.; Sears, J.; Bennett, N.; Rose, D. V.; Welch, D. R.
2015-11-01
A dense plasma focus (DPF) device is a type of plasma gun that drives current through a set of coaxial electrodes to assemble gas inside the device and then implode that gas on axis to form a Z-pinch. This implosion drives hydrodynamic and kinetic instabilities that generate strong electric fields, which produces a short intense pulse of x-rays, high-energy (>100 keV) electrons and ions, and (in deuterium gas) neutrons. A strong factor in pinch performance is the initial breakdown and ionization of the gas along the insulator surface separating the two electrodes. The smoothness and isotropy of this ionized sheath are imprinted on the current sheath that travels along the electrodes, thus making it an important portion of the DPF to both understand and optimize. Here we use kinetic simulations in the Particle-in-cell code LSP to model the breakdown. Simulations are initiated with neutral gas and the breakdown modeled self-consistently as driven by a charged capacitor system. We also investigate novel geometries for the insulator and electrodes to attempt to control the electric field profile. The initial ionization fraction of gas is explored computationally to gauge possible advantages of pre-ionization which could be created experimentally via lasers or a glow-discharge. Prepared by LLNL under Contract DE-AC52-07NA27344.
Multisymplectic Integration for Beam and Plasma Simulations
Webb, Stephen; RadiaSoft, LLC Team
2015-11-01
Particle-in-cell methods are a standard tool for simulating charged particle systems such as fusion plasmas, intense beams, and laser- and beam-driven wakefield accelerators. Conventional methods have been successful in studying short-term dynamics, however numerical instabilities and artifacts such as grid heating make long-time simulations unreliable. A similar issue existed in single particle tracking for storage rings in the 1980s, which led to the development of symplectic algorithms. The essential insight that if the physical equations of motion derive from a least-action principle, then so too should the numerical equations of motion. The resulting update sequence preserves a symplectic 2-form, which is a strong constraint on the numerical solutions. The resulting algorithms are stable and accurate over very long simulation times. This same structure exists for field theories as well as single-particle dynamics. Such multisymplectic integrators have good stability properties and naturally encode conservation laws, making them ideal for simulations over many oscillations of the system. We present here a number of examples where multisymplectic algorithms have been used over very long time scales. This work was sponsored by the Air Force Office of Scientific Research, Young Investigator Program, under contract no. FA9550-15-C-0031. Distribution Statement A. Approved for public release; distribution is unlimited.
Subramaniam, Vivek; Raja, Laxminarayan L.
2017-06-01
Recent experiments by Loebner et al. [IEEE Trans. Plasma Sci. 44, 1534 (2016)] studied the effect of a hypervelocity jet emanating from a coaxial plasma accelerator incident on target surfaces in an effort to mimic the transient loading created during edge localized mode disruption events in fusion plasmas. In this paper, we present a magnetohydrodynamic (MHD) numerical model to simulate plasma jet formation and plasma-surface contact in this coaxial plasma accelerator experiment. The MHD system of equations is spatially discretized using a cell-centered finite volume formulation. The temporal discretization is performed using a fully implicit backward Euler scheme and the resultant stiff system of nonlinear equations is solved using the Newton method. The numerical model is employed to obtain some key insights into the physical processes responsible for the generation of extreme stagnation conditions on the target surfaces. Simulations of the plume (without the target plate) are performed to isolate and study phenomena such as the magnetic pinch effect that is responsible for launching pressure pulses into the jet free stream. The simulations also yield insights into the incipient conditions responsible for producing the pinch, such as the formation of conductive channels. The jet-target impact studies indicate the existence of two distinct stages involved in the plasma-surface interaction. A fast transient stage characterized by a thin normal shock transitions into a pseudo-steady stage that exhibits an extended oblique shock structure. A quadratic scaling of the pinch and stagnation conditions with the total current discharged between the electrodes is in qualitative agreement with the results obtained in the experiments. This also illustrates the dominant contribution of the magnetic pressure term in determining the magnitude of the quantities of interest.
Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode.
Poehlmann, Flavio R; Cappelli, Mark A; Rieker, Gregory B
2010-12-01
Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively.
Directory of Open Access Journals (Sweden)
Yingnian Wu
2014-01-01
Full Text Available Electromagnetic calculation plays an important role in both military and civic fields. Some methods and models proposed for calculation of electromagnetic wave propagation in a large range bring heavy burden in CPU computation and also require huge amount of memory. Using the GPU to accelerate computation and visualization can reduce the computational burden on the CPU. Based on forward ray-tracing method, a transmission particle model (TPM for calculating electromagnetic field is presented to combine the particle method. The movement of a particle obeys the principle of the propagation of electromagnetic wave, and then the particle distribution density in space reflects the electromagnetic distribution status. The algorithm with particle transmission, movement, reflection, and diffraction is described in detail. Since the particles in TPM are completely independent, it is very suitable for the parallel computing based on GPU. Deduction verification of TPM with the electric dipole antenna as the transmission source is conducted to prove that the particle movement itself represents the variation of electromagnetic field intensity caused by diffusion. Finally, the simulation comparisons are made against the forward and backward ray-tracing methods. The simulation results verified the effectiveness of the proposed method.
Scattering of electromagnetic waves by counter-rotating vortex streets in plasmas
Energy Technology Data Exchange (ETDEWEB)
Guerra, R.; Mendonca, J.T. [Centro de Electrodinamica, Instituto Superior Tecnico, 1096 Lisboa Codex (Portugal); Dendy, R.O. [UKAEA Government Division, Fusion (UKAEA---Euratom Fusion Association), Culham, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Shukla, P.K. [Institut fuer Theoretische Physik IV, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)
1996-03-01
The scattering of electromagnetic waves from counter-rotating vortex streets associated with nonlinear convective cells in uniform plasmas has been considered. The vortex street solution of the Navier{endash}Stokes or the Hasegawa{endash}Mima (and of the {open_quote}{open_quote}sinh-Poisson{close_quote}{close_quote}) equation is adopted as a scatterer. Assuming arbitrary polarization and profile function for the incident electromagnetic field, a compact expression for the scattering cross section has been obtained. Specific results for the differential cross section are obtained for the case in which the incident beam has a Gaussian profile and propagates as an ordinary mode. The results show that when the characteristic wavelength of the vortex street ({lambda}{sub {ital v}}=2{pi}/{ital a}) is larger than that of the incident electromagnetic wave ({lambda}{sub {ital i}}=2{pi}/{ital k}{sub {ital i}}), the differential cross section {ital d}{sigma}/{ital d}{Omega} has a very well-defined angular periodicity; in fact, it is a collection of Gaussians varying as exp[{minus}{ital f}({ital k}{sub {ital iw}}){sup 2}], where {ital w} is the waist and {ital f} is a function expressing a kind of {open_quote}{open_quote}Bragg condition.{close_quote}{close_quote} On the other hand, for {lambda}{sub {ital i}}{approx_gt}{lambda}{sub {ital v}} the incident electromagnetic beam is unable to distinguish the periodic structure of the vortex street. The effects of the vortex street as well as the incident beam parameters on the scattering cross section are examined. {copyright} {ital 1996 American Institute of Physics.}
Mildaziene, Vida; Pauzaite, Giedre; Malakauskiene, Asta; Zukiene, Rasa; Nauciene, Zita; Filatova, Irina; Azharonok, Viktor; Lyushkevich, Veronika
2016-08-30
Radiofrequency (5.28 MHz) electromagnetic radiation and low-temperature plasma were applied as short-term (2-15 min) seed treatments to two perennial woody plant species, including Smirnov's rhododendron (Rhododendron smirnowii Trautv.) and black mulberry (Morus nigra L.). Potential effects were evaluated using germination indices and morphometry. The results suggest that treatment with electromagnetic field stimulated germination of freshly harvested R. smirnowii seeds (increased germination percentage up to 70%), but reduced germination of fresh M. nigra seeds (by 24%). Treatment with low-temperature plasma negatively affected germination for R. smirnowii, and positively for M. nigra. The treatment-induced changes in germination depended on seed dormancy state. Longer-term observations revealed that the effects persisted for more than a year; however, even negative effects on germination came out as positive effects on plant morphometric traits over time. Treatments characterized as distressful based on changes in germination and seedling length increased growth of R. smirnowii after 13 months. Specific changes included stem and root branching, as well as increased leaf count and surface area. These findings imply that longer-term patterns of response to seed stressors may be complex, and therefore, commonly used stressor-effects estimates, such as germination rate or seedling morphology, may be insufficient for qualifying stress response. Bioelectromagnetics. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Plasma simulation studies using multilevel physics models
International Nuclear Information System (INIS)
Park, W.; Belova, E.V.; Fu, G.Y.
2000-01-01
The question of how to proceed toward ever more realistic plasma simulation studies using ever increasing computing power is addressed. The answer presented here is the M3D (Multilevel 3D) project, which has developed a code package with a hierarchy of physics levels that resolve increasingly complete subsets of phase-spaces and are thus increasingly more realistic. The rationale for the multilevel physics models is given. Each physics level is described and examples of its application are given. The existing physics levels are fluid models (3D configuration space), namely magnetohydrodynamic (MHD) and two-fluids; and hybrid models, namely gyrokinetic-energetic-particle/MHD (5D energetic particle phase-space), gyrokinetic-particle-ion/fluid-electron (5D ion phase-space), and full-kinetic-particle-ion/fluid-electron level (6D ion phase-space). Resolving electron phase-space (5D or 6D) remains a future project. Phase-space-fluid models are not used in favor of delta f particle models. A practical and accurate nonlinear fluid closure for noncollisional plasmas seems not likely in the near future
Plasma simulation studies using multilevel physics models
Energy Technology Data Exchange (ETDEWEB)
Park, W.; Belova, E.V.; Fu, G.Y. [and others
2000-01-19
The question of how to proceed toward ever more realistic plasma simulation studies using ever increasing computing power is addressed. The answer presented here is the M3D (Multilevel 3D) project, which has developed a code package with a hierarchy of physics levels that resolve increasingly complete subsets of phase-spaces and are thus increasingly more realistic. The rationale for the multilevel physics models is given. Each physics level is described and examples of its application are given. The existing physics levels are fluid models (3D configuration space), namely magnetohydrodynamic (MHD) and two-fluids; and hybrid models, namely gyrokinetic-energetic-particle/MHD (5D energetic particle phase-space), gyrokinetic-particle-ion/fluid-electron (5D ion phase-space), and full-kinetic-particle-ion/fluid-electron level (6D ion phase-space). Resolving electron phase-space (5D or 6D) remains a future project. Phase-space-fluid models are not used in favor of delta f particle models. A practical and accurate nonlinear fluid closure for noncollisional plasmas seems not likely in the near future.
International Nuclear Information System (INIS)
Cristofolini, Andrea; Neretti, Gabriele; Borghi, Carlo A.
2012-01-01
This work proposes an experimental analysis on the magneto hydro dynamic (MHD) interaction induced by a magnetic test body immersed into a hypersonic argon flow. The characteristic plasma parameters are measured. They are related to the voltages arising in the Hall direction and to the variation of the fluid dynamic properties induced by the interaction. The tests have been performed in a hypersonic wind tunnel at Mach 6 and Mach 15. The plasma parameters are measured in the stagnation region in front of the nozzle of the wind tunnel and in the free stream region at the nozzle exit. The test body has a conical shape with the cone axis in the gas flow direction and the cone vertex against the flow. It is placed at the nozzle exit and is equipped with three permanent magnets. In the configuration adopted, the Faraday current flows in a closed loop completely immersed into the plasma of the shock layer. The electric field and the pressure variation due to MHD interaction have been measured on the test body walls. Microwave adsorption measurements have been used for the determination of the electron number density and the electron collision frequency. Continuum recombination radiation and line radiation emissions have been detected. The electron temperature has been determined by means of the spectroscopic data by using different methods. The electron number density has been also determined by means of the Stark broadening of H α and the H β lines. Optical imaging has been utilized to visualize the pattern of the electric current distribution in the shock layer around the test body. The experiments show a considerable effect of the electromagnetic forces produced by the MHD interaction acting on the plasma flow around the test body. A comparison of the experimental data with simulation results shows a good agreement.
Computational electromagnetic-aerodynamics
Shang, Joseph J S
2016-01-01
Presents numerical algorithms, procedures, and techniques required to solve engineering problems relating to the interactions between electromagnetic fields, fluid flow, and interdisciplinary technology for aerodynamics, electromagnetics, chemical-physics kinetics, and plasmadynamics This book addresses modeling and simulation science and technology for studying ionized gas phenomena in engineering applications. Computational Electromagnetic-Aerodynamics is organized into ten chapters. Chapter one to three introduce the fundamental concepts of plasmadynamics, chemical-physics of ionization, classical magnetohydrodynamics, and their extensions to plasma-based flow control actuators, high-speed flows of interplanetary re-entry, and ion thrusters in space exploration. Chapter four to six explain numerical algorithms and procedures for solving Maxwell’s equation in the time domain for computational electromagnetics, plasma wave propagation, and the time-dependent c mpressible Navier-Stokes equation for aerodyn...
PIC Simulations of Dense Plasma Focus Z-pinch
Schmidt, A.; Blackfield, D.; Tang, V.; Welch, D.; Rose, D.
2011-10-01
Dense Plasma Focus (DPF) Z-pinches are abundant sources of radiation, including neutrons, x-rays, and energetic electron and ion beams. Energetic protons and deuterons up to 10 MeV have been observed from cm-scale-length pinches, implying average acceleration gradients up to 1 GV/m. Gradients of this magnitude could potentially be exploited in the design of a compact accelerator. However, the physical mechanisms behind these immense electric fields are not well understood and thus DPF design cannot currently be optimized to maximize these gradients. At LLNL, we have assembled a DPF Z-pinch experiment and will be using a 4 MV ion probe beam to directly measure pinch-induced gradients. LSP, a fully relativistic electromagnetic Particle-In-Cell (PIC) code is used to perform time-dependent simulations of the pinch phase of the DPF and to gain insight into the origin and evolution of the large accelerating fields. LSP can be used in 2D or 3D geometries and can model the ions kinetically with fluid electrons (hybrid model) or model both species kinetically (fully kinetic model). We present results from both pressure and sheath width scans using LSP. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (11-ERD-063) at LLNL.
Electromagnetic Simulations for Aerospace Application Final Report CRADA No. TC-0376-92
Energy Technology Data Exchange (ETDEWEB)
Madsen, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Meredith, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2018-01-24
Electromagnetic (EM) simulation tools play an important role in the design cycle, allowing optimization of a design before it is fabricated for testing. The purpose of this cooperative project was to provide Lockheed with state-of-the-art electromagnetic (EM) simulation software that will enable the optimal design of the next generation of low-observable (LO) military aircraft through the VHF regime. More particularly, the project was principally code development and validation, its goal to produce a 3-D, conforming grid,time-domain (TD) EM simulation tool, consisting of a mesh generator, a DS13D-based simulation kernel, and an RCS postprocessor, which was useful in the optimization of LO aircraft, both for full-aircraft simulations run on a massively parallel computer and for small scale problems run on a UNIX workstation.
Frozen-shower simulation of electromagnetic showers in the ATLAS forward calorimeter
Gasnikova, Ksenia; The ATLAS collaboration
2016-01-01
Accurate simulation of calorimeter response for high energy electromagnetic particles is essential for the LHC experiments. Detailed simulation of the electromagnetic showers using Geant4 is however very CPU intensive and various fast simulation methods were proposed instead. The frozen shower simulation substitutes the full propagation of the showers for energies below 1~GeV by showers taken from a pre-simulated library. The method is used for production of the main ATLAS Monte Carlo samples, greatly improving the production time. The frozen showers describe shower shapes, sampling fraction, sampling and noise-related fluctuations very well, while description of the constant term, related to calorimeter non-uniformity, requires a careful choice of the shower library binning. A new method is proposed to tune the binning variables, using multivariate techniques. The method is tested and optimized for the description of the ATLAS forward calorimeter.
Directory of Open Access Journals (Sweden)
Bing He
2015-01-01
Full Text Available Using parallel computation can enhance the performance of numerical simulation of electromagnetic radiation and get great runtime reduction. We simulate the electromagnetic radiation calculation based on the multicore CPU and GPU Parallel Architecture Clusters by using MPI-OpenMP and MPI-CUDA hybrid parallel algorithm. This is an effective solution comparing to the traditional finite-difference time-domain method which has a shortage in the calculation of the electromagnetic radiation on the problem of inadequate large data space and time. What is more, we use regional segmentation, subregional data communications, consolidation, and other methods to improve procedures nested parallelism and finally verify the correctness of the calculation results. Studying these two hybrid models of parallel algorithms run on the high-performance cluster computer, we draw the conclusion that both models are suitable for large-scale numerical calculations, and MPI-CUDA hybrid model can achieve higher speedup.
Kotoka, Jonas; Kriek, Jeanne
2014-01-01
The impact of computer simulations on the performance of 65 grade 11 learners in electromagnetism in a South African high school in the Mpumalanga province is investigated. Learners did not use the simulations individually, but teachers used them as an interactive demonstration tool. Basic concepts in electromagnetism are difficult to understand…
RF wave simulation for cold edge plasmas using the MFEM library
Shiraiwa, S.; Wright, J. C.; Bonoli, P. T.; Kolev, T.; Stowell, M.
2017-10-01
A newly developed generic electro-magnetic (EM) simulation tool for modeling RF wave propagation in SOL plasmas is presented. The primary motivation of this development is to extend the domain partitioning approach for incorporating arbitrarily shaped SOL plasmas and antenna to the TORIC core ICRF solver, which was previously demonstrated in the 2D geometry [S. Shiraiwa, et. al., "HISTORIC: extending core ICRF wave simulation to include realistic SOL plasmas", Nucl. Fusion in press], to larger and more complicated simulations by including a 3D realistic antenna and integrating RF rectified sheath potential model. Such an extension requires a scalable high fidelity 3D edge plasma wave simulation. We used the MFEM [http://mfem.org], open source scalable C++ finite element method library, and developed a Python wrapper for MFEM (PyMFEM), and then a radio frequency (RF) wave physics module in Python. This approach allows for building a physics layer rapidly, while separating the physics implementation being apart from the numerical FEM implementation. An interactive modeling interface was built on pScope [S Shiraiwa, et. al. Fusion Eng. Des. 112, 835] to work with an RF simulation model in a complicated geometry.
Simulating magnetised plasma with the versatile advection code
Keppens, R.; Toth, G.; Palma, J. M. L.; Dongarra, J.; Hernandez, V.
1999-01-01
Matter in the universe mainly consists of plasma. The dynamics of plasmas is controlled by magnetic fields. To simulate the evolution of magnetised plasma, we solve the equations of magnetohydrodynamics using the Versatile Advection Code (VAC). To demonstrate the versatility of VAC, we present
Emergence of MHD structures in a collisionless PIC simulation plasma
Dieckmann, M. E.; Folini, D.; Walder, R.; Romagnani, L.; d'Humieres, E.; Bret, A.; Karlsson, T.; Ynnerman, A.
2017-09-01
The expansion of a dense plasma into a dilute plasma across an initially uniform perpendicular magnetic field is followed with a one-dimensional particle-in-cell simulation over magnetohydrodynamics time scales. The dense plasma expands in the form of a fast rarefaction wave. The accelerated dilute plasma becomes separated from the dense plasma by a tangential discontinuity at its back. A fast magnetosonic shock with the Mach number 1.5 forms at its front. Our simulation demonstrates how wave dispersion widens the shock transition layer into a train of nonlinear fast magnetosonic waves.
Detailed electromagnetic simulation for the structural color of butterfly wings.
Lee, R Todd; Smith, Glenn S
2009-07-20
Many species of butterflies exhibit interesting optical phenomena due to structural color. The physical reason for this color is subwavelength features on the surface of a single scale. The exposed surface of a scale is covered with a ridge structure. The fully three-dimensional, periodic, finite-difference time-domain method is used to create a detailed electromagnetic model of a generic ridge. A novel method for presenting the three-dimensional observed color pattern is developed. Using these tools, the change in color that is a result of varying individual features of the scale is explored. Computational models are developed that are similar to three butterflies: Morpho rhetenor, Troides magellanus, and Ancyluris meliboeus.
International Nuclear Information System (INIS)
Kawamura, E; Lichtenberg, A J; Lieberman, M A; Marakhtanov, A M
2016-01-01
A fast 2D axisymmetric fluid-analytical multifrequency capacitively coupled plasma (CCP) reactor code is used to study center high nonuniformity in a low pressure electronegative chlorine discharge. In the code, a time-independent Helmholtz wave equation is used to solve for the capacitive fields in the linearized frequency domain. This eliminates the time dependence from the electromagnetic (EM) solve, greatly speeding up the simulations at the cost of neglecting higher harmonics. However, since the code allows up to three driving frequencies, we can add the two most important harmonics to the CCP simulations as the second and third input frequencies. The amplitude and phase of these harmonics are estimated by using a recently developed 1D radial nonlinear transmission line (TL) model of a highly asymmetric cylindrical discharge (Lieberman et al 2015 Plasma Sources Sci. Technol. 24 055011). We find that at higher applied frequencies, the higher harmonics contribute significantly to the center high nonuniformity due to their shorter plasma wavelengths. (paper)
Chen, Wei; Guo, Li-xin; Li, Jiang-ting
2017-04-01
This study analyzes the scattering characteristics of obliquely incident electromagnetic (EM) waves in a time-varying plasma sheath. The finite-difference time-domain algorithm is applied. According to the empirical formula of the collision frequency in a plasma sheath, the plasma frequency, temperature, and pressure are assumed to vary with time in the form of exponential rise. Some scattering problems of EM waves are discussed by calculating the radar cross section (RCS) of the time-varying plasma. The laws of the RCS varying with time are summarized at the L and S wave bands.
Mattei, S.; Nishida, K.; Onai, M.; Lettry, J.; Tran, M. Q.; Hatayama, A.
2017-12-01
We present a fully-implicit electromagnetic Particle-In-Cell Monte Carlo collision code, called NINJA, written for the simulation of inductively coupled plasmas. NINJA employs a kinetic enslaved Jacobian-Free Newton Krylov method to solve self-consistently the interaction between the electromagnetic field generated by the radio-frequency coil and the plasma response. The simulated plasma includes a kinetic description of charged and neutral species as well as the collision processes between them. The algorithm allows simulations with cell sizes much larger than the Debye length and time steps in excess of the Courant-Friedrichs-Lewy condition whilst preserving the conservation of the total energy. The code is applied to the simulation of the plasma discharge of the Linac4 H- ion source at CERN. Simulation results of plasma density, temperature and EEDF are discussed and compared with optical emission spectroscopy measurements. A systematic study of the energy conservation as a function of the numerical parameters is presented.
Plasma radiation in tokamak disruption simulation experiments
International Nuclear Information System (INIS)
Arkhipov, N.; Bakhtin, V.; Safronov, V.; Toporkov, D.; Vasenin, S.; Zhitlukhin, A.; Wuerz, H.
1995-01-01
Plasma impact results in sudden evaporation of divertor plate material and produces a plasma cloud which acts as a protective shield. The incoming energy flux is absorbed in the plasma shield and is converted mainly into radiation. Thus the radiative characteristics of the target plasma determine the dissipation of the incoming energy and the heat load at the target. Radiation of target plasma is studied at the two plasma gun facility 2MK-200 at Troitsk. Space- and time-resolved spectroscopy and time-integrated space-resolved calorimetry are employed as diagnostics. Graphite and tungsten samples are exposed to deuterium plasma streams. It is found that the radiative characteristics depend strongly on the target material. Tungsten plasma arises within 1 micros close to the surface and shows continuum radiation only. Expansion of tungsten plasma is restricted. For a graphite target the plasma shield is a mixture of carbon and deuterium. It expands along the magnetic field lines with a velocity of v = (3--4) 10 6 cm/s. The plasma shield is a two zone plasma with a hot low dense corona and a cold dense layer close to the target. The plasma corona emits intense soft x-ray (SXR) line radiation in the frequency range from 300--380 eV mainly from CV ions. It acts as effective dissipation system and converts volumetrically the incoming energy flux into SXR radiation
Plasma radiation in tokamak disruption simulation experiments
Energy Technology Data Exchange (ETDEWEB)
Arkhipov, N.; Bakhtin, V.; Safronov, V.; Toporkov, D.; Vasenin, S.; Zhitlukhin, A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Wuerz, H. [Forschungszentrum Karlsruhe (Germany)
1995-12-31
Plasma impact results in sudden evaporation of divertor plate material and produces a plasma cloud which acts as a protective shield. The incoming energy flux is absorbed in the plasma shield and is converted mainly into radiation. Thus the radiative characteristics of the target plasma determine the dissipation of the incoming energy and the heat load at the target. Radiation of target plasma is studied at the two plasma gun facility 2MK-200 at Troitsk. Space- and time-resolved spectroscopy and time-integrated space-resolved calorimetry are employed as diagnostics. Graphite and tungsten samples are exposed to deuterium plasma streams. It is found that the radiative characteristics depend strongly on the target material. Tungsten plasma arises within 1 {micro}s close to the surface and shows continuum radiation only. Expansion of tungsten plasma is restricted. For a graphite target the plasma shield is a mixture of carbon and deuterium. It expands along the magnetic field lines with a velocity of v = (3--4) 10{sub 6} cm/s. The plasma shield is a two zone plasma with a hot low dense corona and a cold dense layer close to the target. The plasma corona emits intense soft x-ray (SXR) line radiation in the frequency range from 300--380 eV mainly from CV ions. It acts as effective dissipation system and converts volumetrically the incoming energy flux into SXR radiation.
Directory of Open Access Journals (Sweden)
Ji Han
2018-02-01
Full Text Available The electromagnetic transient simulation of a power system with nonlinear characteristics is very time-consuming due to numerous inversion calculations of the admittance matrix. To speed up the simulation of the power system with nonlinear characteristics, a multi-rate and parallel electromagnetic transient simulation method is proposed. Firstly, a Multi-Area Thevenin Equivalents (MATE-based parallel algorithm considering nonlinear characteristics of the power system is proposed. This method guarantees the admittance matrix is constant by considering changing branches as link current without dividing the subnet again. Secondly, considering the differences of the time constant of the AC/DC subnet, different simulation steps are used for these subnets. The Lagrange interpolation method is used for calculating the Thevenin voltage of the AC subnet in non-synchronous time. Calculation methods of the DC subnet Thevenin voltage is proposed by considering the simulation results during the entire large simulation step. Finally, the simulation process is optimized for improving the simulation efficiency further. The simulation results show that the proposed method could greatly improve the simulation efficiency without losing simulation accuracy too much compared with the traditional method.
Full wave simulation of waves in ECRIS plasmas based on the finite element method
Energy Technology Data Exchange (ETDEWEB)
Torrisi, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123, Catania, Italy and Università Mediterranea di Reggio Calabria, Dipartimento di Ingegneria dell' Informazione, delle Infrastrutture e dell' Energia Sostenibile (DIIES), Via Graziella, I (Italy); Mascali, D.; Neri, L.; Castro, G.; Patti, G.; Celona, L.; Gammino, S.; Ciavola, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123, Catania (Italy); Di Donato, L. [Università degli Studi di Catania, Dipartimento di Ingegneria Elettrica Elettronica ed Informatica (DIEEI), Viale Andrea Doria 6, 95125 Catania (Italy); Sorbello, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123, Catania, Italy and Università degli Studi di Catania, Dipartimento di Ingegneria Elettrica Elettronica ed Informatica (DIEEI), Viale Andrea Doria 6, 95125 Catania (Italy); Isernia, T. [Università Mediterranea di Reggio Calabria, Dipartimento di Ingegneria dell' Informazione, delle Infrastrutture e dell' Energia Sostenibile (DIIES), Via Graziella, I-89100 Reggio Calabria (Italy)
2014-02-12
This paper describes the modeling and the full wave numerical simulation of electromagnetic waves propagation and absorption in an anisotropic magnetized plasma filling the resonant cavity of an electron cyclotron resonance ion source (ECRIS). The model assumes inhomogeneous, dispersive and tensorial constitutive relations. Maxwell's equations are solved by the finite element method (FEM), using the COMSOL Multiphysics{sup ®} suite. All the relevant details have been considered in the model, including the non uniform external magnetostatic field used for plasma confinement, the local electron density profile resulting in the full-3D non uniform magnetized plasma complex dielectric tensor. The more accurate plasma simulations clearly show the importance of cavity effect on wave propagation and the effects of a resonant surface. These studies are the pillars for an improved ECRIS plasma modeling, that is mandatory to optimize the ion source output (beam intensity distribution and charge state, especially). Any new project concerning the advanced ECRIS design will take benefit by an adequate modeling of self-consistent wave absorption simulations.
Simulation of plasma sheath turbulence for magneto-inertial fusion (MIF)
Krasheninnikova, Natalia; Tang, Xianzhu; Roytershteyn, Vadim; Daughton, William
2009-05-01
A leading approach to achieve MIF is to use an imploding metal liner to compress magnetized target plasma to thermonuclear temperatures. For MIF applications, the magnetic field is parallel to the liner surface, which causes the ions, with their large gyro-radii, to positively charge the liner. This creates a strong ExB shear flow which can cause turbulence and regulate. Here we report on progress of the simulation studies of plasma sheath turbulence using a state-of-the-art VPIC [1] code. Baseline calculations are carried out examine the possibility of establishing a quiescent sheath plasma equilibrium in 1D for a flat liner surface and 2D for the shaped one, which should be unstable when 2D and 3D dynamics are allowed. The details of plasma sheath parameters from these runs, allows us to examine the regimes of various instabilities and their nonlinear saturation.[3pt] [1] K. J. Bowers, et al., ``Ultra high performance 3D electromagnetic relativistic kinetic plasma simulation,'' Phys. Plasmas 15, 055703 (2008).
Speeding up predictive electromagnetic simulations for ITER application
Energy Technology Data Exchange (ETDEWEB)
Alekseev, A.B. [ITER Organization, Route de Vinon sur Verdon, 13067 St. Paul Lez Durance Cedex (France); Amoskov, V.M. [JSC “NIIEFA”, Doroga na Metallostroy 3, St. Petersburg, 196641 (Russian Federation); Bazarov, A.M., E-mail: alexander.bazarov@gmail.com [JSC “NIIEFA”, Doroga na Metallostroy 3, St. Petersburg, 196641 (Russian Federation); Belov, A.V. [JSC “NIIEFA”, Doroga na Metallostroy 3, St. Petersburg, 196641 (Russian Federation); Belyakov, V.A. [JSC “NIIEFA”, Doroga na Metallostroy 3, St. Petersburg, 196641 (Russian Federation); St. Petersburg State University, 7/9 Universitetskaya Embankment, St. Petersburg, 199034 (Russian Federation); Gapionok, E.I. [JSC “NIIEFA”, Doroga na Metallostroy 3, St. Petersburg, 196641 (Russian Federation); Gornikel, I.V. [Alphysica GmbH, Unterreut, 6, D-76135, Karlsruhe (Germany); Gribov, Yu. V. [ITER Organization, Route de Vinon sur Verdon, 13067 St. Paul Lez Durance Cedex (France); Kukhtin, V.P.; Lamzin, E.A. [JSC “NIIEFA”, Doroga na Metallostroy 3, St. Petersburg, 196641 (Russian Federation); Sytchevsky, S.E. [JSC “NIIEFA”, Doroga na Metallostroy 3, St. Petersburg, 196641 (Russian Federation); St. Petersburg State University, 7/9 Universitetskaya Embankment, St. Petersburg, 199034 (Russian Federation)
2017-05-15
Highlights: • A general concept of engineering EM simulator for tokamak application is proposed. • An algorithm is based on influence functions and superposition principle. • The software works with extensive databases and offers parallel processing. • The simulator allows us to obtain the solution hundreds times faster. - Abstract: The paper presents an attempt to proceed to a general concept of software environment for fast and consistent multi-task simulation of EM transients (engineering simulator for tokamak applications). As an example, the ITER tokamak is taken to introduce a computational technique. The strategy exploits parallel processing with optimized simulation algorithms based on using of influence functions and superposition principle to take full advantage of parallelism. The software has been tested on a multi-core supercomputer. The results were compared with data obtained in TYPHOON computations. A discrepancy was found to be below 0.4%. The computation cost for the simulator is proportional to the number of observation points. An average computation time with the simulator is found to be by hundreds times less than the time required to solve numerically a relevant system of differential equations for known software tools.
The Parameterized Simulation of Electromagnetic Showers in Homogeneous and Sampling Calorimeters
Grindhammer, G.; Peters, S.
2000-01-01
A general approach to a fast simulation of electromagnetic showers using parameterizations of the longitudinal and radial profiles in homogeneous and sampling calorimeters is described. The dependence of the shower development on the materials used and the sampling geometry is taken into account explicitly. Comparisons with detailed simulations of various calorimeters and with data from the liquid argon calorimeter of the H1 experiment are made.
Evidence of L-mode electromagnetic wave pumping of ionospheric plasma near geomagnetic zenith
Leyser, Thomas B.; James, H. Gordon; Gustavsson, Björn; Rietveld, Michael T.
2018-02-01
The response of ionospheric plasma to pumping by powerful HF (high frequency) electromagnetic waves transmitted from the ground into the ionosphere is the strongest in the direction of geomagnetic zenith. We present experimental results from transmitting a left-handed circularly polarized HF beam from the EISCAT (European Incoherent SCATter association) Heating facility in magnetic zenith. The CASSIOPE (CAScade, Smallsat and IOnospheric Polar Explorer) spacecraft in the topside ionosphere above the F-region density peak detected transionospheric pump radiation, although the pump frequency was below the maximum ionospheric plasma frequency. The pump wave is deduced to arrive at CASSIOPE through L-mode propagation and associated double (O to Z, Z to O) conversion in pump-induced radio windows. L-mode propagation allows the pump wave to reach higher plasma densities and higher ionospheric altitudes than O-mode propagation so that a pump wave in the L-mode can facilitate excitation of upper hybrid phenomena localized in density depletions in a larger altitude range. L-mode propagation is therefore suggested to be important in explaining the magnetic zenith effect.
Evidence of L-mode electromagnetic wave pumping of ionospheric plasma near geomagnetic zenith
Directory of Open Access Journals (Sweden)
T. B. Leyser
2018-02-01
Full Text Available The response of ionospheric plasma to pumping by powerful HF (high frequency electromagnetic waves transmitted from the ground into the ionosphere is the strongest in the direction of geomagnetic zenith. We present experimental results from transmitting a left-handed circularly polarized HF beam from the EISCAT (European Incoherent SCATter association Heating facility in magnetic zenith. The CASSIOPE (CAScade, Smallsat and IOnospheric Polar Explorer spacecraft in the topside ionosphere above the F-region density peak detected transionospheric pump radiation, although the pump frequency was below the maximum ionospheric plasma frequency. The pump wave is deduced to arrive at CASSIOPE through L-mode propagation and associated double (O to Z, Z to O conversion in pump-induced radio windows. L-mode propagation allows the pump wave to reach higher plasma densities and higher ionospheric altitudes than O-mode propagation so that a pump wave in the L-mode can facilitate excitation of upper hybrid phenomena localized in density depletions in a larger altitude range. L-mode propagation is therefore suggested to be important in explaining the magnetic zenith effect.
The polarization evolution of electromagnetic waves as a diagnostic method for a motional plasma
Shahrokhi, Alireza; Mehdian, Hassan; Hajisharifi, Kamal; Hasanbeigi, Ali
2017-12-01
The polarization evolution of electromagnetic (EM) radiation propagating through an electron beam-ion channel system is studied in the presence of self-magnetic field. Solving the fluid-Maxwell equations to obtain the medium dielectric tensor, the Stokes vector-Mueller matrix approach is employed to determine the polarization of the launched EM wave at any point in the propagation direction, applying the space-dependent Mueller matrix on the initial polarization vector of the wave at the plasma-vacuum interface. Results show that the polarization evolution of the wave is periodic in space along the beam axis with the specified polarization wavelength. Using the obtained results, a novel diagnostic method based on the polarization evolution of the EM waves is proposed to evaluate the electron beam density and velocity. Moreover, to use the mentioned plasma system as a polarizer, the fraction of the output radiation power transmitted through a motional plasma crossed with the input polarization is calculated. The results of the present investigation will greatly contribute to design a new EM amplifier with fixed polarization or EM polarizer, as well as a new diagnostic approach for the electron beam system where the polarimetric method is employed.
Resistive Magnetohydrodynamics Simulation of Fusion Plasmas
International Nuclear Information System (INIS)
Tang, X.Z.; Fu, G.Y.; Jardin, S.C.; Lowe, L.L.; Park, W.; Strauss, H.R.
2001-01-01
Although high-temperature plasmas in laboratory magnetic fusion confinements are sufficiently collisionless that formal fluid closures are difficult to attain, the resistive MHD model has proven, by comparison with experimental data, to be useful for describing the large scale dynamics of magnetized plasmas. Resistive MHD model consists of Faraday's law for the evolution of the magnetic field and Navier-Stokes equation for the plasma flow. These equations are closed by the Ohm's law and an equation of state for the plasma
Electro-magnetic design and simulation of wall current monitor sensor for LEHIPA
International Nuclear Information System (INIS)
Shukla, Hitesh; Kumar, Amit; Singh, S.K.; Dixit, M.Y.; Joshi, Gopal
2015-01-01
Beam diagnostic instruments are essential component of any accelerator. Wall current monitors (WCMs) are common beam diagnostic tools used for acquiring the temporal distribution of the charged particle bunches. This paper discusses the electro-magnetic design and simulation results of Wall current Monitor sensor being developed at Electronics Division, BARC with a bandwidth from 16.9 MHz to 30 GHz. As per the simulation results, output of the sensor for a 0.30A peak current bunched beam will be 0.8 Vpeak to peak. The simulations were carried out for Eigen modes, Particle In Cell (PIC) and Wake-field simulations using CST Microwave Studio Suite. (author)
International Nuclear Information System (INIS)
Holm, D.D.; Kupershmidt, B.A.
1987-01-01
Four levels of nonlinear hydrodynamic description are presented for a nondissipative multicondensate solution of superfluids with vorticity. First, the multivelocity superfluid (MVSF) theory is extended to the case of a multivelocity superfluid plasma (MVSP), in which some of the superfluid condensates (protons, say) are charged and coupled electromagnetically to an additional, normal, charged fluid (electrons). The resulting drag-current density is derived due to the electromagnetic coupling of the condensates with the normal fluids. For the case of one charged condensate, the MVSP equations simplify to what we call superfluid Hall magnetohydrodynamics (SHMHD) in the approximation that displacement current and electron inertia are negligible, and local charge neutrality is imposed. The contribution of the charged condensate to the Hall drift force is determined. In turn, neglecting the Hall effect in SHMHD gives the equations of superfluid magnetohydrodynamics (SMHD). Each set of equations (MVSF, MVSP, SHMHD, and SMHD) is shown to be Hamiltonian and to possess a Poisson bracket associated with the dual space of a corresponding semidirect-product Lie algebra with a generalized two-cocycle defined on it. Topological conservation laws (helicities) associated with the kernels of these Lie algebras are also discussed as well as those associated physically with generalized Kelvin theorems for conservation of superfluid circulation around closed loops moving with the normal fluid
Frequency-domain multiscale quantum mechanics/electromagnetics simulation method
Energy Technology Data Exchange (ETDEWEB)
Meng, Lingyi; Yin, Zhenyu; Yam, ChiYung, E-mail: yamcy@yangtze.hku.hk, E-mail: ghc@everest.hku.hk; Koo, SiuKong; Chen, GuanHua, E-mail: yamcy@yangtze.hku.hk, E-mail: ghc@everest.hku.hk [Department of Chemistry, The University of Hong Kong, Pokfulam Road (Hong Kong); Chen, Quan; Wong, Ngai [Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)
2013-12-28
A frequency-domain quantum mechanics and electromagnetics (QM/EM) method is developed. Compared with the time-domain QM/EM method [Meng et al., J. Chem. Theory Comput. 8, 1190–1199 (2012)], the newly developed frequency-domain QM/EM method could effectively capture the dynamic properties of electronic devices over a broader range of operating frequencies. The system is divided into QM and EM regions and solved in a self-consistent manner via updating the boundary conditions at the QM and EM interface. The calculated potential distributions and current densities at the interface are taken as the boundary conditions for the QM and EM calculations, respectively, which facilitate the information exchange between the QM and EM calculations and ensure that the potential, charge, and current distributions are continuous across the QM/EM interface. Via Fourier transformation, the dynamic admittance calculated from the time-domain and frequency-domain QM/EM methods is compared for a carbon nanotube based molecular device.
Hajijamali-Arani, Zeinab; Jazi, Bahram
2017-11-01
This article presents a formulation for the dielectric permittivity tensor in a long column of warm drift homogeneous plasma taking into account the drift velocity of the particles, the rotating magnetic field and the effects of the electron-ion collisions. In this formulation, the study of the waves propagating along the cylindrical axis is employed, in the case for which the ions and electrons are described by the different drift velocities. Using the fundamental electromagnetic equations and the fluid equations in a cylindrical coordinate system, the time variable dielectric permittivity tensor is obtained and the coupling equations of the fields will be derived. It is shown that in the absence of the thermal and the collisional effects the limiting special cases will be satisfied.
Rustan, Pedro L., Jr.
1987-01-01
Lightning data obtained by measuring the surface electromagnetic fields on a CV-580 research aircraft during 48 lightning strikes between 1500 and 18,000 feet in central Florida during the summers of 1984 and 1985, and nuclear electromagnetic pulse (NEMP) data obtained by surface electromagnetic field measurements using a 1:74 CV-580 scale model, are presented. From one lightning event, maximum values of 3750 T/s for the time rate of change of the surface magnetic flux density, and 4.7 kA for the peak current, were obtained. From the simulated NEMP test, maximum values of 40,000 T/s for the time rate of change of the surface magnetic flux density, and 90 A/sq m for the total normal current density, were found. The data have application to the development of a military aircraft lightning/NEMP standard.
GENERAL RELATIVISTIC SIMULATIONS OF MAGNETIZED PLASMAS AROUND MERGING SUPERMASSIVE BLACK HOLES
Energy Technology Data Exchange (ETDEWEB)
Giacomazzo, Bruno [JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, CO 80309 (United States); Baker, John G.; Van Meter, James R. [Gravitational Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 21114 (United States); Coleman Miller, M.; Reynolds, Christopher S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
2012-06-10
Coalescing supermassive black hole binaries are produced by the mergers of galaxies and are the most powerful sources of gravitational waves accessible to space-based gravitational observatories. Some such mergers may occur in the presence of matter and magnetic fields and hence generate an electromagnetic counterpart. In this Letter, we present the first general relativistic simulations of magnetized plasma around merging supermassive black holes using the general relativistic magnetohydrodynamic code Whisky. By considering different magnetic field strengths, going from non-magnetically dominated to magnetically dominated regimes, we explore how magnetic fields affect the dynamics of the plasma and the possible emission of electromagnetic signals. In particular, we observe a total amplification of the magnetic field of {approx}2 orders of magnitude, which is driven by the accretion onto the binary and that leads to much stronger electromagnetic signals, more than a factor of 10{sup 4} larger than comparable calculations done in the force-free regime where such amplifications are not possible.
International Nuclear Information System (INIS)
Wang, Jing; Yusa, Noritaka; Hashizume, Hidetoshi; Pan Hongliang; Kemppainen, Mika; Virkkuen, Iikka
2012-01-01
The present study discusses electromagnetic characteristics of modeling thermal fatigue crack in numerical simulation from view point of eddy current testing. Two thermal fatigue cracks introduced into SUS304 stainless steel plates are investigated. Eddy current signals are gathered by a differential plus point probe with several frequencies, 50 kHz, 100 kHz and 400 kHz. In the numerical simulation thermal fatigue crack is modeled as a region with constant width, true profile revealed by results of destructive testing, and uniform conductivity firstly. Further simulations are carried out to consider the possibility of variation of electromagnetic characteristics around the edge of crack. The results show that thermal fatigue cracks should be modeled as an almost nonconductive region no matter how the frequency is utilized. (author)
Numerical simulation of hull curved plate forming by electromagnetic force assisted line heating
Wang, Ji; Wang, Shun; Liu, Yujun; Li, Rui; Liu, xiao
2017-11-01
Line heating is a common method in shipyards for forming of hull curved plate. The aluminum alloy plate is widely used in shipbuilding. To solve the problem of thick aluminum alloy plate forming with complex curved surface, a new technology named electromagnetic force assisted line heating(EFALH) was proposed in this paper. The FEM model of EFALH was established and the effect of electromagnetic force assisted forming was verified by self development equipment. Firstly, the solving idea of numerical simulation for EFALH was illustrated. Then, the coupled numerical simulation model of multi physical fields were established. Lastly, the reliability of the numerical simulation model was verified by comparing the experimental data. This paper lays a foundation for solving the forming problems of thick aluminum alloy curved plate in shipbuilding.
Liu, Wei; Hsu, Scott C.
2010-01-01
We present results from three-dimensional ideal magnetohydrodynamic simulations of unmagnetized dense plasma jet injection into a uniform hot strongly magnetized plasma, with the aim of providing insight into core fueling of a tokamak with parameters relevant for ITER and NSTX (National Spherical Torus Experiment). Unmagnetized dense plasma jet injection is similar to compact toroid injection but with much higher plasma density and total mass, and consequently lower required injection velocit...
Fluid simulation of the conduction phase of the plasma erosion opening switch
International Nuclear Information System (INIS)
Grossmann, J.M.; Mosher, D.; Ottinger, P.F.
1987-01-01
The conduction phase of the plasma erosion openings switch (PEOS) is studied using a 1 1/2-D electromagnetic two-fluid code. The focus of this work is on understanding how two effects, a current-limiting model of electron emission, and the magnetic insulation of electrons at the cathode, determine current conduction in the plasma. Simulations are performed in the parameter regimes of the Gamble I, POP, and PBFA II pulsed power generators, and previous low-density, short-rise time simulations of the PEOS. Fluid code results are compared to a 1-D analytic theory and to the Gamble I and POP experiments. Good agreement between theory and simulation, but mixed agreement between simulation and experiment is found. Experimental Β-field measurements on POP show weaker j x Β compression than the simulation. Current penetration and plasma current channels qualitatively similar to experimental observation are found in the Gamble I regime. However, magnetic insulation of electrons emitted from the cathode bunches the electron flow into narrower current channels than observed experimentally. In several cases, the presence of an electron-scattering or energy-loss mechanism near the cathode must be invoked to overcome magnetic insulation and widen the current channels
Energy Technology Data Exchange (ETDEWEB)
Yuan, Hongwei; Yuan, Zhensheng; Li, Weixin; Pei, Cuixiang; Xie, Shejuan [State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Research Center for NDT and Structural Integrity Evaluation, Xi’an Jiaotong University, Xi’an 710049 (China); Chen, Zhenmao, E-mail: chenzm@mail.xjtu.edu.cn [State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Research Center for NDT and Structural Integrity Evaluation, Xi’an Jiaotong University, Xi’an 710049 (China); Pan, Yudong; Cai, Lijun; Li, Jiaxian [Southwestern Institute of Physics, Chengdu 610041 (China)
2016-11-01
Highlights: • A 1/5 numerical model is established and validated for HL-2M vacuum vessel. • The Lagrangian approach used for treating the EM-mechanical coupling problem is introduced. • The EM field and structural dynamic response of HL-2M VV during plasma disruptions are simulated by using the Lagrangian strategy. • The dynamic responses of the VV of HL-2M are compared to clarify the effect of the EM-mechanical coupling under the MD and VED conditions. • The results present a basis for the safe operation of the HL-2M VV device. - Abstract: During plasma disruptions (PDs), transient eddy currents are induced in the HL-2M vacuum vessel (VV) which is a D-shaped, double thin-wall structure. Under the circumstance of high magnetic field, the resulting electromagnetic (EM) forces during PDs are large and the dynamic response of related structures may be violent. In this complicated EM circumstance, the EM-mechanical coupling effect may also have a great influence on the dynamic response of VV structure. In this paper, the EM field and structural dynamic response of HL-2M VV during PDs are simulated by adopting a numerical code of the Lagrangian approach. The Lagrangian approach is on the basis of the Maxwell equations in the Lagrangian description, which treats the coupling behavior of magnetic damping effect without explicitly using the velocity term. This approach can be easily applied to actual structures by updating FEM meshes and reforming coefficient matrices before calculating EM field at each time step. In this work, the disruption plasma currents of operating conditions are simulated by using the DINA code and then the dynamic responses of displacements and stresses of the VV of HL-2M are obtained for both cases with and without considering the coupling effect. The numerical results show that stresses under the disruptions (MD and VDE) are not significant and the coupling effect does not significantly affect the peak dynamic response for the HL-2M
Miotk, R.; Jasiński, M.; Mizeraczyk, J.
2018-03-01
This paper presents the partial electromagnetic optimisation of a 2.45 GHz cylindrical-type microwave plasma source (MPS) operated at atmospheric pressure. The presented device is designed for hydrogen production from liquid fuels, e.g. hydrocarbons and alcohols. Due to industrial requirements regarding low costs for hydrogen produced in this way, previous testing indicated that improvements were required to the electromagnetic performance of the MPS. The MPS has a duct discontinuity region, which is a result of the cylindrical structure located within the device. The microwave plasma is generated in this discontinuity region. Rigorous analysis of the region requires solving a set of Maxwell equations, which is burdensome for complicated structures. Furthermore, the presence of the microwave plasma increases the complexity of this task. To avoid calculating the complex Maxwell equations, we suggest the use of the equivalent circuit method. This work is based upon the idea of using a Weissfloch circuit to characterize the area of the duct discontinuity and the plasma. The resulting MPS equivalent circuit allowed the calculation of a capacitive metallic diaphragm, through which an improvement in the electromagnetic performance of the plasma source was obtained.
International Nuclear Information System (INIS)
Xia Xiongping; Yi Lin
2012-01-01
Effect of higher order axial electron temperature on self-focusing of electromagnetic pulsed beam in collisional plasma is investigated. It is shown that higher order axial electron temperature T p4 is not trivial than T p0 and T p2 , which can modify slightly radial redistribution of electron density and increases effective dielectric constant. As a result, on one hand, slightly reduce electromagnetic beam self-focusing in the course of oscillatory convergence, on the other hand, quicken beam divergence in the course of steady divergence, i.e., higher order axial electron temperature T p4 can decrease the influence of collisional nonlinearity in collisional plasma. (physics of gases, plasmas, and electric discharges)
HIDENEK: an implicit particle simulation of kinetic-MHD phenomena in three-dimensional plasmas
International Nuclear Information System (INIS)
Tanaka, Motohiko.
1993-05-01
An advanced 'kinetic-MHD' simulation method and its applications to plasma physics are given in this lecture. This method is quite suitable for studying strong nonlinear, kinetic processes associated with large space-scale, low-frequency electromagnetic phenomena of plasmas. A full set of the Maxwell equations, and the Newton-Lorentz equations of motion for particle ions and guiding-center electrons are adopted. In order to retain only the low-frequency waves and instabilities, implicit particle-field equations are derived. The present implicit-particle method is proved to reproduce the MHD eigenmodes such as Alfven, magnetosonic and kinetic Alfven waves in a thermally near-equilibrium plasma. In the second part of the lecture, several physics applications are shown. These include not only the growth of the instabilities of beam ions against the background plasmas and helical kink of the current, but they also demonstrate nonlinear results such as pitch-angle scattering of the ions. Recent progress in the simulation of the Kelvin-Helmholtz instability is also presented with a special emphasis on the mixing of plasma particles. (author)
Tzenov, Stephan I.
2017-12-01
Starting from the Vlasov-Maxwell equations describing the dynamics of various species in a quasi-neutral plasma, an exact relativistic hydrodynamic closure for a special type of water-bag distribution satisfying the Vlasov equation has been derived. It has been shown that the set of equations for the macroscopic hydrodynamic variables coupled to the wave equations for the self-consistent electromagnetic field is fully equivalent to the Vlasov-Maxwell system. Based on the method of multiple scales, a system comprising a vector nonlinear Schrodinger equation for the transverse envelopes of the self-consistent plasma wakefield, coupled to a scalar nonlinear Schrodinger equation for the electron current velocity envelope, has been derived. Using the method of formal series of Dubois-Violette, a traveling wave solution of the derived set of coupled nonlinear Schrodinger equations in the case of circular wave polarization has been obtained. This solution is represented as a ratio of two formal Volterra series. The terms of these series can be calculated explicitly to every desired order.
Implementation of SoC Based Real-Time Electromagnetic Transient Simulator
Directory of Open Access Journals (Sweden)
I. Herrera-Leandro
2017-01-01
Full Text Available Real-time electromagnetic transient simulators are important tools in the design stage of new control and protection systems for power systems. Real-time simulators are used to test and stress new devices under similar conditions that the device will deal with in a real network with the purpose of finding errors and bugs in the design. The computation of an electromagnetic transient is complex and computationally demanding, due to features such as the speed of the phenomenon, the size of the network, and the presence of time variant and nonlinear elements in the network. In this work, the development of a SoC based real-time and also offline electromagnetic transient simulator is presented. In the design, the required performance is met from two sides, (a using a technique to split the power system into smaller subsystems, which allows parallelizing the algorithm, and (b with specialized and parallel hardware designed to boost the solution flow. The results of this work have shown that for the proposed case studies, based on a balanced distribution of the node of subsystems, the proposed approach has decreased the total simulation time by up to 99 times compared with the classical approach running on a single high performance 32-bit embedded processor ARM-Cortex A9.
Directory of Open Access Journals (Sweden)
Munkhbaatar Batmunkh
2015-12-01
Full Text Available Problems of the radiobiology and the nuclear medicine require clarifying the specifi cs of radionuclides interactions with unhealthy cells. In this work we aimed to simulate emitting particles tracks of radionuclides and their radioactive decays at DNA level inside the cell nucleus. Accordingly, using the Monte Carlo-based track structure simulation technique, we estimated the radial distribution of deposited energy and kinetic energy spectra of electrons produced by primary particles resulting from radioactive decays of diff erent radionuclides within cell nucleus. To address the possibility of DNA damage, we performed the cluster analysis of track structures of emitted particles inside the volumes corresponding to the size of the native double-stranded DNA. For this purpose, G4-RadioactiveDecay and low- energy electromagnetic packages form Geant4 Monte-Carlo toolkit were combined together. Besides, a comparative analysis was performed for various low-energy electromagnetic packages as G4-DNA and G4-Livermore
Directory of Open Access Journals (Sweden)
Ping Li
2018-03-01
Full Text Available In this paper, performances of vibration energy harvester combined piezoelectric (PE and electromagnetic (EM mechanism are studied by theoretical analysis, simulation and experimental test. For the designed harvester, electromechanical coupling modeling is established, and expressions of vibration response, output voltage, current and power are derived. Then, performances of the harvester are simulated and tested; moreover, the power charging rechargeable battery is realized through designed energy storage circuit. By the results, it’s found that compared with piezoelectric-only and electromagnetic-only energy harvester, the hybrid energy harvester can enhance the output power and harvesting efficiency; furthermore, at the harmonic excitation, output power of harvester linearly increases with acceleration amplitude increasing; while it enhances with acceleration spectral density increasing at the random excitation. In addition, the bigger coupling strength, the bigger output power is, and there is the optimal load resistance to make the harvester output the maximal power.
Analysis and simulation of electromagnetic transients in HVAC cable transmission grids
Energy Technology Data Exchange (ETDEWEB)
DA Silva, F.M.F.
2011-07-15
Denmark is the first country in the world undergrounding most of its transmission network. As a result, several technical barriers and challenges associated to the use of an undergrounded transmission grid must first be dealt with. For that purpose, several research and development projects were initiated by the Danish TSO, among them this PhD thesis. The main objective of this PhD is to study electromagnetic transient phenomena. Thereto, the thesis is divided into two main parts: 1) Description of the different electromagnetic phenomena likely to occur in transmission grids with a large amount of HVAC cables and respective countermeasures; 2) Guidelines for the proper simulation of those phenomena when using EMTP software, more specifically PSCAD/EMTDC, and methods to optimize the simulations; A simulation network based on the Transmission Grid of West Denmark as planned for 2030 has been used as simulation base case to identify the dimensioning transient phenomena and find the right countermeasures for an undergrounded transmission network. In order to ensure that the transient studies are made on a proper model basis, the frequency dependent phasor model in PSCAD/EMTDC has been verified by measurements on a 100 km, 58 km of land cable plus 42 km of submarine cable, 165 kV cable, which is connecting an offshore wind farm to the Danish transmission network. The 2030 West Denmark Grid has two voltage levels, 165 kV and 400 kV. The 165 kV level will be all cables, whereas the 400 kV level will mostly be cables. This network provides the necessary complexity for the electromagnetic studies. The accuracy of cable simulation models has been addressed by several authors prior to this thesis. However, the validations were normally made for short cables, whereas in this thesis are analysed cables with dozens of km length. The thesis shows the measurement's results and demonstrates that the land cable model is accurate, yet the same is not true for the used submarine
Modelling of dusty plasma properties by computer simulation methods
Energy Technology Data Exchange (ETDEWEB)
Baimbetov, F B [IETP, Al Farabi Kazakh National University, 96a, Tole bi St, Almaty 050012 (Kazakhstan); Ramazanov, T S [IETP, Al Farabi Kazakh National University, 96a, Tole bi St, Almaty 050012 (Kazakhstan); Dzhumagulova, K N [IETP, Al Farabi Kazakh National University, 96a, Tole bi St, Almaty 050012 (Kazakhstan); Kadyrsizov, E R [Institute for High Energy Densities of RAS, Izhorskaya 13/19, Moscow 125412 (Russian Federation); Petrov, O F [IETP, Al Farabi Kazakh National University, 96a, Tole bi St, Almaty 050012 (Kazakhstan); Gavrikov, A V [IETP, Al Farabi Kazakh National University, 96a, Tole bi St, Almaty 050012 (Kazakhstan)
2006-04-28
Computer simulation of dusty plasma properties is performed. The radial distribution functions, the diffusion coefficient are calculated on the basis of the Langevin dynamics. A comparison with the experimental data is made.
Two-dimensional Simulations of Correlation Reflectometry in Fusion Plasmas
International Nuclear Information System (INIS)
Valeo, E.J.; Kramer, G.J.; Nazikian, R.
2001-01-01
A two-dimensional wave propagation code, developed specifically to simulate correlation reflectometry in large-scale fusion plasmas is described. The code makes use of separate computational methods in the vacuum, underdense and reflection regions of the plasma in order to obtain the high computational efficiency necessary for correlation analysis. Simulations of Tokamak Fusion Test Reactor (TFTR) plasma with internal transport barriers are presented and compared with one-dimensional full-wave simulations. It is shown that the two-dimensional simulations are remarkably similar to the results of the one-dimensional full-wave analysis for a wide range of turbulent correlation lengths. Implications for the interpretation of correlation reflectometer measurements in fusion plasma are discussed
Three-dimensional simulation of laser–plasma-based electron ...
Indian Academy of Sciences (India)
–plasma-based electron acceleration has been carried out to assess the performance of this code. Simulations have been ... The electron energy spectrum has been evaluated at different time-steps during the propagation of the laser beam.
Three-dimensional simulation of laser–plasma-based electron ...
Indian Academy of Sciences (India)
Abstract. A sequential three-dimensional (3D) particle-in-cell simulation code PICPSI-3D with a user friendly graphical user interface (GUI) has been developed and used to study the interaction of plasma with ultrahigh intensity laser radiation. A case study of laser–plasma-based electron acceleration has been carried out ...
Plasma simulations using the Car-Parrinello method
International Nuclear Information System (INIS)
Clerouin, J.; Zerah, G.; Benisti, D.; Hansen, J.P.
1990-01-01
A simplified version of the Car-Parrinello method, based on the Thomas-Fermi (local density) functional for the electrons, is adapted to the simulation of the ionic dynamics in dense plasmas. The method is illustrated by an explicit application to a degenerate one-dimensional hydrogen plasma
Voitcu, Gabriel; Echim, Marius
2014-05-01
The dynamics of collisionless plasma jets/clouds in magnetic field configurations typical for the terrestrial magnetotail and frontside magnetosheath is a topic of interest for understanding the physics of the magnetosphere and its interaction with the solar wind. The presence of high-speed jets in the frontside magnetosheath has been recently proved experimentally by Cluster and THEMIS spacecrafts. There is increasing evidence that the bursty bulk flows in the magnetotail have jet-like features. In the present paper we use fully electromagnetic 3D explicit particle-in-cell (PIC) simulations to investigate the interaction of a localized three-dimensional plasma element/jet/cloud with a transverse magnetic field. We consider a plasma jet/cloud that moves in vacuum and perpendicular to an ambient magnetic field. Ampère and Faraday's laws are used to compute the self-consistent electric and magnetic fields on a three-dimensional spatial grid having a step-size of the order of the Debye length and using a time-step that resolves the plasma frequency. The initial magnetic field inside the simulation domain is uniform and the plasma bulk velocity at the beginning of the simulation is normal to the magnetic field direction. The total time scale of the simulation is of the order of few ion Larmor periods. Space and time variations of the plasma parameters and of the electromagnetic field are analyzed and discussed. We emphasize non-MHD effects like the energy-dispersion signatures at the edges of the plasma element, similar to results previously reported by Voitcu and Echim (2012) using test-kinetic simulations. Acknowledgments: Research supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 313038/STORM, and a grant of the Romanian Ministry of National Education, CNCS - UEFISCDI, project number PN-II-ID-PCE-2012-4-0418.
Electromagnetic field effect simulation over a realistic pixel ed phantom human's brain
International Nuclear Information System (INIS)
Rojas, R.; Calderon, J. A.; Rivera, T.; Azorin, J.
2012-10-01
The exposition to different types of electromagnetic radiations can produce damages and injures on the people's tissues. The scientist, spend time and resources studying the effects of electromagnetic fields over the organs. Particularly in medical areas, the specialist in imaging methodologies and radiological treatment, are very worried about no injure there patient. Determination of matter radiation interaction, can be experimental or theoretical is not an easy task anyway. At first case, is not possible make measures inside the patient, then the experimental procedure consist in make measures in human's dummy, however, is not possible see deformations of electromagnetic fields due the organs presence. In the second case, is necessary solve, the Maxwell's equations with the electromagnetic field, crossing a lot of organs and tissues with different electric and magnetic properties each one. One alternative for theoretical solution, is make a computational simulation, however, this option, require an enormous quantity of memory and large computational times. Then, the most simulations are making in 2 dimensional or in 3 dimensional although using human models approximations, build ed with basic geometrical figures, like spheres, cylinders, ellipsoids, etc. Obviously this models just lets obtain a coarse solution of the actually situation. In this work, we propose a novel methodology to build a realistic pixel ed phantom of human's organs, and solve the Maxwell's equations over this models, evidently, the solutions are more approximated to the real behaviour. Additionally, there models results optimized when they are discretized and the finite element method is used to calculate the electromagnetic field and the induced currents. (Author)
MED101: a laser-plasma simulation code. User guide
International Nuclear Information System (INIS)
Rodgers, P.A.; Rose, S.J.; Rogoyski, A.M.
1989-12-01
Complete details for running the 1-D laser-plasma simulation code MED101 are given including: an explanation of the input parameters, instructions for running on the Rutherford Appleton Laboratory IBM, Atlas Centre Cray X-MP and DEC VAX, and information on three new graphics packages. The code, based on the existing MEDUSA code, is capable of simulating a wide range of laser-produced plasma experiments including the calculation of X-ray laser gain. (author)
Conceptual Design and Simulation of a Miniature Plasma Focus
International Nuclear Information System (INIS)
Jafari, H.; Habibi, M.; Amrollahi, R.
2012-01-01
Design and construction of a miniature plasma focus device with 3.6 J of energy bank is reported. In design the device, some of very important parameters of designing such as plasma energy density and derive parameter was used. Regarding to the electrical and geometrical parameters of the device, a simulation is carried out by MATLAB software. Simulation results showed that the formation of the pinch have occurred at the moment of the peak discharge current.
Computational Simulation of High Energy Density Plasmas
2009-10-30
the imploding liner. The PFS depends on a lithium barrier foil slowing the advance of deuterium up the coaxial gun to the corner. There the plasma ...the coaxial gun section, and Figure 4 shows the physical state of the plasma just prior to pinch. Figure 5 shows neutron yield reaching 1014 in this...details the channel geometry between the center cylinder and coaxial gas gun . The deuterium injection starts when the pressure of the deuterium gas in
3D electromagnetic simulation of spatial autoresonance acceleration of electron beams
International Nuclear Information System (INIS)
Dugar-Zhabon, V D; Orozco, E A; González, J D
2016-01-01
The results of full electromagnetic simulations of the electron beam acceleration by a TE 112 linear polarized electromagnetic field through Space Autoresonance Acceleration mechanism are presented. In the simulations, both the self-sustaned electric field and selfsustained magnetic field produced by the beam electrons are included into the elaborated 3D Particle in Cell code. In this system, the space profile of the magnetostatic field maintains the electron beams in the acceleration regime along their trajectories. The beam current density evolution is calculated applying the charge conservation method. The full magnetic field in the superparticle positions is found by employing the trilinear interpolation of the mesh node data. The relativistic Newton-Lorentz equation presented in the centered finite difference form is solved using the Boris algorithm that provides visualization of the beam electrons pathway and energy evolution. A comparison between the data obtained from the full electromagnetic simulations and the results derived from the motion equation depicted in an electrostatic approximation is carried out. It is found that the self-sustained magnetic field is a factor which improves the resonance phase conditions and reduces the beam energy spread. (paper)
Comparing DINA code simulations with TCV experimental plasma equilibrium responses
International Nuclear Information System (INIS)
Khayrutdinov, R.R.; Lister, J.B.; Lukash, V.E.; Wainwright, J.P.
2000-08-01
The DINA non-linear time dependent simulation code has been validated against an extensive set of plasma equilibrium response experiments carried out on the TCV tokamak. Limited and diverted plasmas are found to be well modelled during the plasma current flat top. In some simulations the application of the PF coil voltage stimulation pulse sufficiently changed the plasma equilibrium that the vertical position feedback control loop became unstable. This behaviour was also found in the experimental work, and cannot be reproduced using linear time-independent models. A single null diverted plasma discharge was also simulated from start-up to shut-down and the results were found to accurately reproduce their experimental equivalents. The most significant difference noted was the penetration time of the poloidal flux, leading to a delayed onset of sawtoothing in the DINA simulation. The complete set of frequency stimulation experiments used to measure the open loop tokamak plasma equilibrium response was also simulated using DINA and the results were analysed in an identical fashion to the experimental data. The frequency response of the DINA simulations agrees with the experimental results. Comparisons with linear models are also discussed to identify areas of good and only occasionally less good agreement. (author)
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...
International Nuclear Information System (INIS)
Bradley, J. III; Sharp, G.; Gahl, J.M. Kuznetsov, V.; Rockett, P.; Hunter, J.
1995-01-01
Tokamak disruption simulation experiments are being conducted at the University of New Mexico (UNM) using the PLADIS I plasma gun system. PLADIS I is a high power, high energy coaxial plasma gun configured to produce an intense plasma beam. First wall candidate materials are placed in the beam path to determine their response under disruption relevant energy densities. An optically thick vapor shield plasma has been observed to form above the target surface in PLADIS I. Various diagnostics have been used to determine the characteristics of the incident plasma and the vapor shielding plasma. The cross sectional area of the incident plasma beam is a critical characteristic, as it is used in the calculation of the incident plasma energy density. Recently, a HeNe interferometer in the Mach-Zehnder configuration has been constructed and used to probe the electron density of the incident plasma beam and vapor shield plasma. The object beam of the interferometer is scanned across the plasma beam on successive shots, yielding line integrals of beam density on different chords through the plasma. Data from the interferometer is used to determine the electron density profile of the incident plasma beam as a function of beam radius. This data is then used to calculate the effective beam area. Estimates. of beam area, obtained from other diagnostics such as damage targets, calorimeter arrays and off-axis measurements of surface pressure, will be compared with data from the interferometer to obtain a better estimate of the beam cross sectional area
Three-dimensional plasma simulation models and their application to magnetically confined plasmas
International Nuclear Information System (INIS)
Okuda, H.
1977-03-01
Three-dimensional plasma simulation models using particles have been described and applied to the various microscopic processes in a plasma in a magnetic field. The model makes use of the hybrid approach using eigenfunction expansion in one direction and multipole expansion on a two-dimensional spatial grid introduced in the cross section of a plasma. The models for cylindrical and toroidal systems correctly reproduce the expected fluctuation spectrum in thermal equilibrium. Application to the study of anomalous plasma diffusion due to collisionless drift instabilities in a cylindrical plasma is shown. Some considerations are given as to how to construct a quasi-neutral particle simulation model and particle-fluid hybrid plasma model which eliminate the high frequency oscillations associated with the electrons
A spectral Poisson solver for kinetic plasma simulation
Szeremley, Daniel; Obberath, Jens; Brinkmann, Ralf
2011-10-01
Plasma resonance spectroscopy is a well established plasma diagnostic method, realized in several designs. One of these designs is the multipole resonance probe (MRP). In its idealized - geometrically simplified - version it consists of two dielectrically shielded, hemispherical electrodes to which an RF signal is applied. A numerical tool is under development which is capable of simulating the dynamics of the plasma surrounding the MRP in electrostatic approximation. In this contribution we concentrate on the specialized Poisson solver for that tool. The plasma is represented by an ensemble of point charges. By expanding both the charge density and the potential into spherical harmonics, a largely analytical solution of the Poisson problem can be employed. For a practical implementation, the expansion must be appropriately truncated. With this spectral solver we are able to efficiently solve the Poisson equation in a kinetic plasma simulation without the need of introducing a spatial discretization.
Simulations of radiative shocks and jet formation in laboratory plasmas
Energy Technology Data Exchange (ETDEWEB)
Velarde, P; Gonzalez, M; GarcIa-Fernandez, C; Oliva, E [Instituto de Fusion Nuclear, Universidad Politcnica de Madrid, Madrid (Spain) (Spain); Kasperczuk, A; Pisarczyk, T [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland) (Poland); Ullschmied, J [Institute of Plasma Physics AS CR, Prague (Czech Republic) (Czech Republic); Stehle, C [LERMA, Observatoire de Paris, Meudon (France) (France); Rus, B [Institute of Physics, PALS Center, Prague (Czech Republic) (Czech Republic); GarcIa-Senz, D; Bravo, E; Relano, A [Departament de Fisica i Enginyeria Nuclear. Universitat Politecnica de Catalunya. Barcelona (Spain) (Spain)], E-mail: velarde@din.upm.es
2008-05-01
We present the simulations of two relevant hydrodynamical problems related to astrophysical phenomena performed by three different codes. The numerical results from these codes will be compared in order to test both the numerical method implemented inside them and the influence of the physical phenomena simulated by the codes. Under some conditions laser produced plasmas could be scaled to the typical conditions prevailing in astrophysical plasmas. Therefore, such similarity allows to use existing laser facilities and numerical codes suitable to a laser plasma regime, for studying astrophysical proccesses. The codes are the radiation fluid dynamic 2D ARWEN code and the 3D HERACLES, and, without radiation energy transport, a Smoothed-Particle Hydrodynamics (SPH) code. These codes use different numerical techniques and have overlapping range of application, from laser produced plasmas to astrophysical plasmas. We also present the first laser experiments obtaining cumulative jets with a velocity higher than 100 km/s.
Monte Carlo simulations for plasma physics
International Nuclear Information System (INIS)
Okamoto, M.; Murakami, S.; Nakajima, N.; Wang, W.X.
2000-07-01
Plasma behaviours are very complicated and the analyses are generally difficult. However, when the collisional processes play an important role in the plasma behaviour, the Monte Carlo method is often employed as a useful tool. For examples, in neutral particle injection heating (NBI heating), electron or ion cyclotron heating, and alpha heating, Coulomb collisions slow down high energetic particles and pitch angle scatter them. These processes are often studied by the Monte Carlo technique and good agreements can be obtained with the experimental results. Recently, Monte Carlo Method has been developed to study fast particle transports associated with heating and generating the radial electric field. Further it is applied to investigating the neoclassical transport in the plasma with steep gradients of density and temperatures which is beyong the conventional neoclassical theory. In this report, we briefly summarize the researches done by the present authors utilizing the Monte Carlo method. (author)
International Nuclear Information System (INIS)
Kriegsmann, G.A.
1976-01-01
In this paper we apply the method of geometrical optics to study the scattering of plane electromagnetic waves off a cylindrically confined cold plasma. For simplicity, we assume two types of incident polarization. In both cases scalar second order elliptic partial differential equations describe the fields. These problems are studied in the asymptotic limit aω/c→infinity (where a is the radius of the cylinder, ω is the frequency of the incident plane wave, and c is the velocity of light in free space). We furthermore assume a quadratic plasma density. This allows us to calculate explicitly the rays, amplitudes, caustics, and other features which arise in the geometrical optics approach. The assumed density also gives rise to the interesting cutoff and resonance phenomenon. Thus the amplification of the electromagnetic fields is observed. This phenomenon may have applications in laser fusion
Simulation on change of generic satellite radar cross section via artificially created plasma sprays
International Nuclear Information System (INIS)
Chung, Shen Shou Max; Chuang, Yu-Chou
2016-01-01
Recent advancements in antisatellite missile technologies have proven the effectiveness of such attacks, and the vulnerability of satellites in such exercises inspires a new paradigm in RF Stealth techniques suitable for satellites. In this paper we examine the possibility of using artificially created plasma sprays on the surface of the satellite’s main body to alter its radar cross section (RCS). First, we briefly review past research related to RF Stealth using plasma. Next, we discuss the physics between electromagnetic waves and plasma, and the RCS number game in RF Stealth design. A comparison of RCS in a generic satellite and a more complicated model is made to illustrate the effect of the RCS number game, and its meaning for a simulation model. We also run a comparison between finite-difference-time-domain (FDTD) and multilevel fast multipole method (MLFMM) codes, and find the RCS results are very close. We then compare the RCS of the generic satellite and the plasma-covered satellite. The incident radar wave is a differentiated Gaussian monopulse, with 3 dB bandwidth between 1.2 GHz and 4 GHz, and we simulate three kinds of plasma density, with a characteristic plasma frequency ω P = 0.1, 1, and 10 GHz. The electron-neutral collision frequency ν en is set at 0.01 GHz. We found the RCS of plasma-covered satellite is not necessarily smaller than the originally satellite. When ω P is 0.1 GHz, the plasma spray behaves like a dielectric, and there is minor reduction in the RCS. When ω P is 1 GHz, the X–Y cut RCS increases. When ω P is 10 GHz, the plasma behaves more like a metal to the radar wave, and stronger RCS dependency to frequency appears. Therefore, to use plasma as an RCS adjustment tool requires careful fine-tuning of plasma density and shape, in order to achieve the so-called plasma stealth effect. (paper)
International Nuclear Information System (INIS)
Deng, Jing; Li, Yaojian; Xu, Yongxiang; Sheng, Hongzhi
2010-01-01
In this work, Magnetic Fluid dynamics (MHD) model is used to stimulate the electromagnetic field, heat transfer and fluid flow in a DC non-transferred arc plasma torch. Through the coupled iterative computation about the electromagnetic equations described by magnetic vector potential format and the modified fluid dynamics equations, the electric potential, temperature and velocity distributions in the torch are obtained. The fluid-solid coupled computation method is applied to treat the electric current and heat transfer at the interface between the electrodes and fluid. The location of arc root attachment at the inside surface of anode and the arc voltage of the torch that we have predicted are very consistent with the corresponding experimental results. The calculated results of the torch are applied to the numerical simulation of the plasma jets under the laminar and turbulent condition. (author)
International Nuclear Information System (INIS)
Yi, Xiaohua; Cho, Chunhee; Wang, Yang; Cooper, James; Tentzeris, Manos M; Leon, Roberto T
2013-01-01
This research investigates a passive wireless antenna sensor designed for strain and crack sensing. When the antenna experiences deformation, the antenna shape changes, causing a shift in the electromagnetic resonance frequency of the antenna. A radio frequency identification (RFID) chip is adopted for antenna signal modulation, so that a wireless reader can easily distinguish the backscattered sensor signal from unwanted environmental reflections. The RFID chip captures its operating power from an interrogation electromagnetic wave emitted by the reader, which allows the antenna sensor to be passive (battery-free). This paper first reports the latest simulation results on radiation patterns, surface current density, and electromagnetic field distribution. The simulation results are followed with experimental results on the strain and crack sensing performance of the antenna sensor. Tensile tests show that the wireless antenna sensor can detect small strain changes lower than 20 με, and can perform well at large strains higher than 10 000 με. With a high-gain reader antenna, the wireless interrogation distance can be increased up to 2.1 m. Furthermore, an array of antenna sensors is capable of measuring the strain distribution in close proximity. During emulated crack and fatigue crack tests, the antenna sensor is able to detect the growth of a small crack. (paper)
Heavy Plasma NAPALM Propulsion Simulation Code
Lörincz, I.; Rugescu, R.D.; Kohlenberg, J.; Prathaban, M.
2010-01-01
The NAPALM project addresses a new and revolutionary space propulsion system, able to deliver a very high specific impulse through a new working fluid and accelerator principle for the electric plasma thruster. The new motor will impressively exceed, by between ten and sixty percent, the vacuum
International Nuclear Information System (INIS)
Bell, T.F.; Ngo, H.D.
1990-01-01
Recent satellite observations demonstrate that high amplitude, short wavelength (5 m ≤ λ ≤ 100 m) electrostatic waves are commonly excited by electromagnetic whistler mode waves propagating in regions of the magnetosphere and topside ionosphere where small-scale magnetic-field-aligned plasma density irregularities are thought to exist. A new theoretical model of this phenomenon is presented, based upon passive linear scattering in a cold magnetoplasma. In this model the electrostatic waves are excited by linear mode coupling as the incident electromagnetic whistler mode waves scatter from the magnetic-field-aligned plasma density irregularities. The excited short wavelength waves are quasi-electrostatic whistler mode waves, a type of lower hybrid wave, whose wave normal lies near the whistler mode resonance cone where the wave refractive index becomes very large. The amplitude of the excited electrostatic lower hybrid waves is calculated for a wide range of values of input electromagnetic wave frequency, wave normal direction, electron plasma frequency, gyrofrequency, ion composition, and irregularity scale and density enhancement. Results indicate that high amplitude lower hybrid waves can be excited over a wide range of parameters for irregularity density enhancements as low as 5% whenever the scale of the irregularity is of the same order as the lower hybrid wavelength
Energy Technology Data Exchange (ETDEWEB)
Guede, Jose Ricardo Abalde
1995-11-01
The aim of this work is to study the nonlinear dynamics of Langmuir and electromagnetic waves in space plasmas. Firstly, the generalized Zakharov equations are derived which are used to study the hybrid parametric instability involving the generation of daughter Langmuir, electromagnetic and ion-acoustic waves induced by two counter-propagating Langmuir pump waves with different amplitudes based on a coupled dispersion relation. Secondly, starting from the generalized Zakharov equations the linear and nonlinear coupled mode theories of three-wave and four-wave parametric interactions are developed, respectively. In three-waves processes, a Langmuir wave decays into another Langmuir wave and an ion-acoustic wave (electrostatic parametric decay) or into an electromagnetic wave and an ion-acoustic wave (electromagnetic parametric decay). In four-wave (modulational) processes, the interaction involves two wave triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplet the coupling of a pump wave with a low-frequency wave generate an anti-Stokes wave. These modulational processes are convective and resonant processes wherein the low-frequency modes are Eigenmodes of plasma and are known as the stimulated modulational processes. Four such processes are investigated in this thesis: two with Langmuir pump waves (electrostatic and hybrid stimulated modulation processes) and the other two with electromagnetic pump waves (stimulated modulation Brillouin scattering and electromagnetic stimulated modulation process). Applications of the theoretical results in space plasmas are discussed. In particular, it is shown that the electrostatic and electromagnetic parametric decay processes of Langmuir waves can model the generation and modulation of radio emissions and Langmuir waves in the
Yatsuka, Eiichi; Kinjo, Kiyotake; Morikawa, Junji; Ogawa, Yuichi
2009-02-01
To identify the mode-converted electron Bernstein wave (EBW) in a torus plasma directly, we have developed an interferometry system, in which a diagnostic microwave injected outside of the plasma column was directly detected with the probing antenna inserted into the plasma. In this work, plasma production and heating are achieved with 2.45 GHz, 2.5 kW electron cyclotron heating (ECH), whereas diagnostics are carried out with a lower power (10 W) separate frequency (1-2.1 GHz) microwave. Three components, i.e., two electromagnetic (toroidal and poloidal directions) and an electrostatic (if refractive index is sufficiently higher than unity, it corresponds to radial component), of ECRF electric field are simultaneously measured with three probing antennas, which are inserted into plasma. Selectivities of each component signal were checked experimentally. Excitation antennas have quite high selectivity of direction of linear polarization. As probing antennas for detecting electromagnetic components, we employed a monopole antenna with a length of 35 mm, and the separation of the poloidal (O-wave) and toroidal (X-wave) components of ECRF electric field could be available with this antenna. To detect EBW, which is an electrostatic wave, a small tip (1 mm) antenna was used. As the preliminary results, we detected signals that have three characteristics of EBW, i.e., short wavelength, backward propagation, and electrostatic.
Simulation of QED effects in ultrahigh intensity laser-plasma interaction
International Nuclear Information System (INIS)
Kostyukov, I.; Nerush, E.
2010-01-01
Complete text of publication follows. Due to an impressive progress in laser technology, laser pulses with peak intensity of nearly 2 x 10 22 W/cm 2 are now available in laboratory. When the matter is irradiated by so intense laser pulses high energy density plasma is produced. Besides of fundamental interest such plasma is the efficient source of particles and radiation with extreme parameters that opens bright perspectives in developments of advanced particle accelerators, next generation of radiation sources, laboratory modelling of astrophysics phenomena etc. Even high laser intensity the radiation reaction and QED effects become important. One of the QED effects, which recently attracts much attention, is the electron-positron plasma creation in strong laser field. The plasma can be produced via electromagnetic cascades: the seeded charged particles is accelerated in the field of counter-propagating laser pulses, then they emit energetic photons, the photons by turn decay in the laser field and create electron-positron pairs. The pair particles accelerated in the laser field produce new generation of the photons and pairs. For self-consistent study of the electron-positron plasma dynamics in the laser field we develop 2D code based on particle-in-cell and Monte-Carlo methods. The electron, positron and photon dynamics as well as evolution of the plasma and laser fields are calculated by PIC technique while photon emission and pair production are calculated by Monte-Carlo method. We simulate pair production in the field of counter-propagating linearly polarized laser pulses. It is shown that for the laser intensity above threshold the plasma production becomes so intense that the laser pulse are strongly absorbed in the plasma. The laser intensity threshold and the rate of laser field absorption are calculated. Acknowledgements. This work has been supported by federal target 'The scientific and scientific-pedagogical personnel of innovation in Russia' and by
Third and fourth quarter progress report on plasma theory and simulation, July 1-December 31, 1986
International Nuclear Information System (INIS)
Birdsall, C.K.
1987-01-01
Our group uses theory and simulation as tools in order to increase the understanding of plasma instabilities, heating, transport, plasma-wall interactions, and large potentials in plasmas. We also work on the improvement of simulation both theoretically and practically
International Nuclear Information System (INIS)
Dieckmann, M.E.
1999-01-01
In this work the emission of high amplitude wave packets into a plasma is examined. The plasma is modelled by an 1 1/2D electromagnetic and relativistic particle in cell code. The antenna is modelled by applying forced electrostatic field oscillations to a subset of the simulation grid cells. The emitted wave packets are followed in space and time. It is investigated how the wave packets are affected by instabilities. The detected instabilities affecting ECH waves have been identified as wave decay, nonlinear damping due to trapping and modulational instabilities. These instabilities have been discussed with hindsight to the plasma sounding experiment. A plasma sounder is an experiment emitting short wave packets into the ambient plasma and then it listens to the response. The assumption that the emitted waves are linear waves then allows to determine the plasma magnetic field strength, the electron density and possibly the electron thermal velocity from the response spectrum. The impact of the non-linear instabilities on the plasma wave response spectrum provided by a sounder have been predicted in this work and the predictions have been shown to match a wide range of experimental observations. A dependence of the instabilities on the simulation noise levels, for example the dependence of the wave interaction time in a wave decay on the noise electric field amplitudes, required it to investigate the simulation noise properties (spectral distribution) and to compare it to real plasma thermal noise. It has also been examined how a finite length antenna would filter the simulation noise. (author)
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.
Numerical Simulations of Plasma Based Flow Control Applications
Suzen, Y. B.; Huang, P. G.; Jacob, J. D.; Ashpis, D. E.
2005-01-01
A mathematical model was developed to simulate flow control applications using plasma actuators. The effects of the plasma actuators on the external flow are incorporated into Navier Stokes computations as a body force vector. In order to compute this body force vector, the model solves two additional equations: one for the electric field due to the applied AC voltage at the electrodes and the other for the charge density representing the ionized air. The model is calibrated against an experiment having plasma-driven flow in a quiescent environment and is then applied to simulate a low pressure turbine flow with large flow separation. The effects of the plasma actuator on control of flow separation are demonstrated numerically.
International Nuclear Information System (INIS)
Dragila, R.; Vukovic, S.
1988-01-01
The properties of surfave waves that are associated with a boundary between a rare plasma and a dense magnetoactive plasma and that propagate along a dc magnetic field are investigated. It is shown that the presence of the magnetic field introduces symmetry in terms of the polarization of the incident electromagnetic wave that excites the surface waves. A surface wave excited by an incident p-polarized (s-polarized) electromagnetic wave leaks in the form of an s-polarized (p-polarized) electromagnetic wave. The rate of rotation of polarization is independent of the polarization of the incident wave. Because a surface wave can leak in the form of an s-polarized electromagnetic wave, it can also be pumped by such a wave, and conditions were found for excitation of a surface wave by an s-polarized incident electromagnetic wave
Mesoscale plasma dynamics, transport barriers and zonal flows: simulations and paradigms
Energy Technology Data Exchange (ETDEWEB)
Thyagaraja, A.; Knight, P.J. [Euratom/Ukaea Fusion Association, Culham Science Centre, Abingdon, OX (United Kingdom); Loureiro, N. [Plasma Physics Group, Imperial College of Science, Technology and Medicine, London (United Kingdom)
2004-06-01
Tokamaks are magnetic confinement fusion devices which seek to produce power from fusion reactions between the isotopes of hydrogen (deuterium and tritium). The understanding of turbulent transport processes which govern the energy, momentum and current distributions in tokamak plasmas is important to optimising the economically viable design of future power plants based on the tokamak concept. With the advent of powerful modern computers it has become possible to model the plasma dynamics on the so-called 'mesoscale' which consists of electromagnetic turbulence with wavelengths intermediate to the ion gyro radius and the system size of typical tokamaks. This paper attempts to describe one such approach which evolves the two-fluid model of a tokamak plasma globally (i.e., both on the macro-scale and the mesoscale), using a nonlinear, electromagnetic, three-dimensional code CUTIE. Recent researches, both theoretical and experimental, on tokamaks indicate the spontaneous (or, externally induced) generation of so-called 'zonal flows', which, under well-defined conditions, can lead to substantial reduction of turbulent transport in localized regions known as transport barriers. This type of confinement enhancement is of great importance in the design and construction of practical fusion power plants and has been the subject of intensive study. In addition to the computational approach based on CUTIE simulations, we also describe some simpler paradigmatic models which are designed to illustrate the genesis of zonal flows by characteristic drift wave fluctuations and the effects of such highly sheared advective flows on the system dynamics. These models help one to understand in a much clearer fashion the rather complex processes simulated by CUTIE. (authors)
Moment aberrations in magneto-electrostatic plasma lenses (computer simulation)
Butenko, V I
2001-01-01
In this work moment aberrations in the plasma magneto-electrostatic lenses are considered in more detail with the use of the computer modeling. For solution of the problem we have developed a special computer code - the model of plasma optical focusing device, allowing to display the main parameters and operations of experimental sample of a lens, to simulate the moment and geometrical aberrations and give recommendations on their elimination.
Computer simulation of plasma turbulence in open systems
International Nuclear Information System (INIS)
Sigov, Yu.S.
1982-01-01
A short review of the results of kinetic simulation of collective phenomena in open plasma systems with the variable total energy and number of particles, i.e., the particle and energy fluxes on boundary surfaces and/or their internal sources and channels is given. Three specific problems are considered in different detail for such systems in one-dimensional geometry: the generation and evolution of double layers in a currently unstable plasma; the collisionless relaxation of strongly non-equilibrium electron distributions; the Langmuir collapse and strong electrostatic turbulence in systems with parametric excitation of a plasma by an external pumping wave and with cooling the fast non-Maxwell electrons. In all these cases the non-linearity and a collective character of processes give examples of new dissipative plasma structures that essentially widen our idea about the nature of the plasma turbulence in non-homogeneous open systems. (Auth.)
Three-fluid magnetohydrodynamical simulation of plasma focus discharges
International Nuclear Information System (INIS)
Behler, K.; Bruhns, H.
1987-01-01
A two-dimensional, three-fluid code based on the two-fluid Potter code [Methods in Computational Physics (Academic, New York, 1970), Vol. 9, p. 340] was developed for simulating the plasma focus discharge. With this code it is possible to treat the neutral gas in addition to the plasma components and to model the ionization and recombination phenomena. Thus the sheet dynamics in a plasma focus can be studied and effects investigated such as the occurrence of residual gas (or plasma) density behind the current sheet in the run-down phase. This is a prerequisite to the occurrence of leak currents, which are one of the causes limiting the performance of large plasma focus devices. It is shown that fast operating foci with small dimensions behave favorably compared with the ''classical'' Mather focus [Methods of Experimental Physics (Academic, New York, 1971), Vol. 9B, p. 187] with long coaxial electrodes
Energy Technology Data Exchange (ETDEWEB)
Xie, Wei, E-mail: cslggncl@163.com [Key Laboratory of Safety Design and Reliability Technology for Engineering Vehicle, Hunan Province, Changsha University of Science and Technology, Changsha 410114 (China); Hunan Province Higher Education Key Laboratory of Modeling and Monitoring on the Near-Earth Electromagnetic Environments, Changsha University of Science & Technology, Changsha 410114 (China); College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Chemical and Biomolecular Engineering Department, University of Tennessee, Knoxville, TN 37996 (United States); Zhu, Xukun; Kuang, Jiacai [Key Laboratory of Safety Design and Reliability Technology for Engineering Vehicle, Hunan Province, Changsha University of Science and Technology, Changsha 410114 (China); Hunan Province Higher Education Key Laboratory of Modeling and Monitoring on the Near-Earth Electromagnetic Environments, Changsha University of Science & Technology, Changsha 410114 (China); Yi, Shihe; Cheng, Haifeng [College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Guo, Zhanhu; He, Qingliang [Chemical and Biomolecular Engineering Department, University of Tennessee, Knoxville, TN 37996 (United States)
2017-06-15
Highlights: • Theoretical formula and calculation results of effective permeability and effective permittivity of the Fe-C coaxial fiber are obtained based on the Maxwell equation. • The coaxial fiber has stronger anisotropy and better electromagnetic dissipation performance than the hollow carbon fiber and solid iron fiber with the same volume content. • Greater conductivity, larger aspect ratio, thin iron shell play important roles to improve the electromagnetic matching ability and microwave attenuation for the Fe-C coaxial fibers. - Abstract: Based on the Maxwell equation, the electromagnetic model in the coaxial fiber was described. The interaction with electromagnetic wave was analysed and the theoretical formula of axial permeability (μ{sub ∥}), axial permittivity (ε{sub ∥}), radial permeability (μ{sub ⊥}) and radial permittivity (ε{sub ⊥}) of Fe-C coaxial fiber were derived, and the demagnetization factor (N) of fibrous material was revised. Calculation results indicate that the composite fiber has stronger anisotropy and better EM dissipation performance than the hollow carbon fiber and solid iron fiber with the same volume content. These properties can be enhanced through increasing aspect ratio and carbon content. The μ{sub ‖} is 5.18-4.46i, μ{sub ⊥} is 2.58-0.50i, ε{sub ∥} is 7.63-6.97i, and ε{sub ⊥} is 1.98-0.15i when the electromagnetic wave frequency is 5 GHz with the outer diameter of 0.866 μm, inner diameter of 0.500 μm, and length of 20 μm. The maximum of the imaginary part of μ{sub ∥} and ε{sub ∥} are much larger than that of μ{sub ⊥} and ε{sub ⊥} when the structural parameters change, and the maximum of μ{sub ∥} and ε{sub ∥} can reach 6.429 and 23.59. Simulation results show that greater conductivity, larger aspect ratio, thin iron shell play important roles to improve the electromagnetic matching ability and microwave attenuation for the Fe-C coaxial fibers.
Energy Technology Data Exchange (ETDEWEB)
Aker, Pamela M.; Bunch, Kyle J.; Jones, Anthony M.
2013-01-01
Previous research at the Pacific Northwest National Laboratory (PNNL) has demonstrated that the low frequency electromagnetic (EM) response of a sealed metallic container interrogated with an encircling coil is a strong function of its contents and can be used to form a distinct signature which can confirm the presence of specific components without revealing hidden geometry or classified design information. Finite element simulations have recently been performed to further investigate this response for a variety of configurations composed of an encircling coil and a typical nuclear material storage container. Excellent agreement was obtained between simulated and measured impedance signatures of electrically conducting spheres placed inside an AT-400R nuclear container. Simulations were used to determine the effects of excitation frequency and the geometry of the encircling coil, nuclear container, and internal contents. The results show that it is possible to use electromagnetic models to evaluate the application of the EM signature technique to proposed versions of nuclear weapons containers which can accommodate restrictions imposed by international arms control and treaty verification legislation.
Progress on the Multiphysics Capabilities of the Parallel Electromagnetic ACE3P Simulation Suite
Energy Technology Data Exchange (ETDEWEB)
Kononenko, Oleksiy [SLAC National Accelerator Lab., Menlo Park, CA (United States)
2015-03-26
ACE3P is a 3D parallel simulation suite that is being developed at SLAC National Accelerator Laboratory. Effectively utilizing supercomputer resources, ACE3P has become a key tool for the coupled electromagnetic, thermal and mechanical research and design of particle accelerators. Based on the existing finite-element infrastructure, a massively parallel eigensolver is developed for modal analysis of mechanical structures. It complements a set of the multiphysics tools in ACE3P and, in particular, can be used for the comprehensive study of microphonics in accelerating cavities ensuring the operational reliability of a particle accelerator.
Packaging of photodetector modules for 100 Gbit/s applications using electromagnetic simulations
DEFF Research Database (Denmark)
Jiang, Chenhui; Krozer, Viktor; Bach, H.-G.
2009-01-01
In this paper we demonstrate ultra-broadband packaging and interconnection designs for photodetector (PD) modules for 100 Gbit/s data transmission applications. The design of packaging and interconnection structures is based on accurate and reliable 3D electromagnetic (EM) simulations. Mode...... conversion loss due to mode mismatch is identified as the dominant effect of limiting bandwidth of packaged modules. Finally, PD chips are successfully packaged by using wire-bonding technology and conventional coplanar waveguide (CPW) for avoiding mode mismatch. The new packaged PD module demonstrates...
Xiong, Hong-Bing; Qian, Li-Juan; Lin, Jian-Zhong
2012-03-01
In this paper, a comprehensive model was developed to investigate the suspension spray for a radio frequency (RF) plasma torch coupled with an effervescent atomizer. Firstly, the RF plasma is simulated by solving the thermo-fluid transport equations with electromagnetic Maxwell equation. Secondly, primary atomization of the suspension is solved by a proposed one-dimensional breakup model and validated with the experimental data. Thirdly, the suspension droplets and discharged nanoparticles are modeled in Lagrangian manner, to calculate each particle tracking, acceleration, heating, melting and evaporation. Saffman lift force, Brownian force and non-continuum effect are considered for nanoparticle momentum transfer, as well as the effects of evaporation on heat transfer. This model predicts the nanoparticle trajectory, velocity, temperature and size in the RF suspension plasma spray. Effects of the torch and atomizer operating conditions on the particle characteristics are investigated. Such operating conditions include gas-to-liquid flow ratio, atomizer orifice diameter, injection pressure, power input level, plasmas gas flow rate, and powder material. The statistical distributions for the multiple particles are also discussed for different cases.
Energy Technology Data Exchange (ETDEWEB)
Rostampooran, Shabnam; Dorranian, Davoud, E-mail: doran@srbiau.ac.ir [Laser Laboratory, Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)
2016-08-15
A system of nonlinear one-dimensional equations of the electron hydrodynamics with Maxwell's equations was developed to describe electromagnetic (EM) solitons in plasma with nonthermal electrons. Equation of vector potential was derived in relativistic regime by implementing the multiple scales technique, and their solitonic answers were introduced. The allowed regions for bright and dark electromagnetic solitons were discussed in detail. Roles of number density of nonthermal electrons, temperature of electrons, and frequency of fast participate of vector potential on the Sagdeev potential and properties of EM soliton were investigated. Results show that with increasing the number of nonthermal electrons, the amplitude of vector potential of bright solitons increases. By increasing the number of nonthermal electrons, dark EM solitons may be changed to bright solitons. Increasing the energy of nonthermal electrons leads to generation of high amplitude solitons.
International Nuclear Information System (INIS)
Sugaya, Reiji
1989-01-01
General expressions of the matrix elements for nonlinear wave-particle scattering (nonlinear Landau and cyclotron damping) of electromagnetic and electrostatic waves in a homogeneous magnetized plasma are derived from the Vlasov-Maxwell equations. The kinetic wave equations obtained for electromagnetic waves are expressed by four-order tensors in the rotating and cartesian coordinates. No restrictions are imposed on the propagation angle to a uniform magnetic field, the Larmor radius, the frequencies, or the wave numbers. By electrostatic approximation of the dielectric tensor and the matrix elements the kinetic wave equations can be applied to the case in which two scattering waves are electrostatic or they are partially electrostatic. Further, the matrix elements in the limit of parallel or perpendicular propagation to the magnetic field are given. (author)
Studies of the ablated plasma from experimental plasma gun disruption simulations
Energy Technology Data Exchange (ETDEWEB)
Rockett, P.D. [Fusion Technology Dept., Sandia National Laboratories, Albuquerque, NM 87185-1129 (United States); Hunter, J.A. [Fusion Technology Dept., Sandia National Laboratories, Albuquerque, NM 87185-1129 (United States); Bradley, J.T. III [Elect. Engin. and Comp. Engin. Dept., Univ. of New Mexico, Albuquerque, NM 87131 (United States); Gahl, J.M. [Elect. Engin. and Comp. Engin. Dept., Univ. of New Mexico, Albuquerque, NM 87131 (United States); Litunovsky, V.N. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus, 189631, St. Petersburg (Russian Federation); Ovchinnokov, I.B. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus, 189631, St. Petersburg (Russian Federation); Ljublin, B.V. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus, 189631, St. Petersburg (Russian Federation); Kuznetsov, B.E. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus, 189631, St. Petersburg (Russian Federation); Titov, V.A. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus, 189631, St. Petersburg (Russian Federation); Zhitlukhin, A. [Troitsk Institute for Innovation and Technology (TRINITI), Troitsk, Moscow Reg. (Russian Federation); Arkhipov, K. [Troitsk Institute for Innovation and Technology (TRINITI), Troitsk, Moscow Reg. (Russian Federation); Bakhtin, V. [Troitsk Institute for Innovation and Technology (TRINITI), Troitsk, Moscow Reg. (Russian Federation); Toporkov, D. [Troitsk Institute for Innovation and Technology (TRINITI), Troitsk, Moscow Reg. (Russian Federation)
1995-04-01
Extensive simulations of tokamak disruptions have provided a picture of material erosion that is limited by the transfer of energy from the incident plasma to the armor solid surface through a dense plasma shield. Radiation spectra were recorded in the VUV and in the visible at the Efremov Laboratories on VIKA using graphite targets. The VUV data were recorded with a Sandia Labs transmission grating spectrograph, covering 1-40 nm. Plasma parameters were evaluated with incident plasma energy densities varying from 10-100 MJ/m{sup 2}. A second transmission grating spectrograph was taken to 2MK-200 at TRINITI to study the plasma-material interface in magnetic cusp plasma. Target materials included POCO graphite, ATJ graphite, boron nitride, and plasma-sprayed tungsten. Detailed spectra were recorded with a spatial resolution of similar 1 mm. Time-resolved data with 40-200 ns resolution was also recorded. The data from both plasma gun facilities demonstrated that the hottest plasma region was sitting several millimeters above the armor tile surface. ((orig.)).
Development of high energy pulsed plasma simulator for plasma-lithium trench experiment
Jung, Soonwook
To simulate detrimental events in a tokamak and provide a test-stand for a liquid lithium infused trench (LiMIT) device, a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. An overall objective of the project is to develop a compact device that can produce 100 MW/m2 to 1 GW/m2 of plasma heat flux (a typical heat flux level in a major fusion device) in ~ 100 mus (≤ 0.1 MJ/m2) for a liquid lithium plasma facing component research. The existing theta pinch device, DEVeX, was built and operated for study on lithium vapor shielding effect. However, a typical plasma energy of 3 - 4 kJ/m2 is too low to study an interaction of plasma and plasma facing components in fusion devices. No or little preionized plasma, ringing of magnetic field, collisions of high energy particles with background gas have been reported as the main issues. Therefore, DEVeX is reconfigured to mitigate these issues. The new device is mainly composed of a plasma gun for a preionization source, a theta pinch for heating, and guiding magnets for a better plasma transportation. Each component will be driven by capacitor banks and controlled by high voltage / current switches. Several diagnostics including triple Langmuir probe, calorimeter, optical emission measurement, Rogowski coil, flux loop, and fast ionization gauge are used to characterize the new device. A coaxial plasma gun is manufactured and installed in the previous theta pinch chamber. The plasma gun is equipped with 500 uF capacitor and a gas puff valve. The increase of the plasma velocity with the plasma gun capacitor voltage is consistent with the theoretical predictions and the velocity is located between the snowplow model and the weak - coupling limit. Plasma energies measured with the calorimeter ranges from 0.02 - 0.065 MJ/m2 and increases with the voltage at the capacitor bank. A cross-check between the plasma energy measured with the calorimeter and the triple probe
International Nuclear Information System (INIS)
Cook, J W S; Chapman, S C; Dendy, R O; Brady, C S
2011-01-01
We present particle-in-cell (PIC) simulations of minority energetic protons in deuterium plasmas, which demonstrate a collective instability responsible for emission near the lower hybrid frequency and its harmonics. The simulations capture the lower hybrid drift instability in a parameter regime motivated by tokamak fusion plasma conditions, and show further that the excited electromagnetic fields collectively and collisionlessly couple free energy from the protons to directed electron motion. This results in an asymmetric tail antiparallel to the magnetic field. We focus on obliquely propagating modes excited by energetic ions, whose ring-beam distribution is motivated by population inversions related to ion cyclotron emission, in a background plasma with a temperature similar to that of the core of a large tokamak plasma. A fully self-consistent electromagnetic relativistic PIC code representing all vector field quantities and particle velocities in three dimensions as functions of a single spatial dimension is used to model this situation, by evolving the initial antiparallel travelling ring-beam distribution of 3 MeV protons in a background 10 keV Maxwellian deuterium plasma with realistic ion-electron mass ratio. These simulations provide a proof-of-principle for a key plasma physics process that may be exploited in future alpha channelling scenarios for magnetically confined burning plasmas.
Modeling of subtle kinetic processes in plasma simulation
International Nuclear Information System (INIS)
Sydora, R.D.; Decyk, V.K.; Dawson, J.M.
1988-01-01
A new diagnostic method for plasma simulation models is presented which enables one to probe the subtle dielectric properties of the plasma medium. The procedure involves the removal of the background plasma response in order to isolate the effects of small perturbing influences which are externally added. We have found the technique accurately describes fundamental kinetic plasma behavior such as the shielding of individual test charges and currents. Wave emission studies and drag of test particles has been carried out in explicit particle algorithms as well as large time step implicit and gyrokinetic models. Accurate plasma behavior is produced and it is possible to investigate in detail, processes which can be compared with plasma kinetic theory. The technique of subtraction is not only limited to particle simulation models but also can be used in MHD or fluid models where resolution is difficult due to the intensity of the background response relative to the phenomena one is interested in measuring, such as a weakly grouwing instability or nonlinear mode coupling effect. (author)
Recent Progress in BOUT + + boundary plasma turbulence simulations
Xu, X. Q.; BOUT++ Team
2017-10-01
BOUT + + has been developed and applied for a range of problems that impact on boundary plasma turbulence and transport. A summary of simulation progress and results will be presented including, but not limited to: (1) Modeling tokamak boundary plasma turbulence and understanding its role in setting divertor heat flux widths; (2) Self-consistent calculation of the radial electric field with ion orbit loss mechanism; (3) Simulating the DIII-D and EAST grassy ELM regime; (4) Simulation comparison of EHO state and broadband MHD phase in near-zero torque QH-mode on DIII-D; (5) Simulation of the ELMs triggering by lithium pellet on EAST tokamak; (6) Ideal MHD Stability and Characteristics of Edge Localized Modes on CFETR Our latest transport module solves a set of transport equations with quasi-neutral constraint using vorticity formulation under the BOUT + + framework. This new capability enables BOUT + + team to simulate boundary plasma transport across the separatrix with self-consistent electric and magnetic drifts, ion orbit loss, and sheath boundary conditions in the scrape-off-layer. Preliminary results of the coupled turbulence and transport simulations will also presented. Prepared by LLNL under Contract DE-AC52-07NA27344.
Electromagnetic simulation of electronic packaging designs (95-ERP-003). 1995 LDRD final report
Energy Technology Data Exchange (ETDEWEB)
Swegle, J.A.
1996-05-01
The primary focus of the project summarized in this report has been to evaluate the performance of the 3D, time-domain electromagnetic code DS13D in the simulation of structures used in microwave microelectronics circuits. We`ve adopted two test cases, coaxial and stripline transmission lines, for which well-known results are available so that results obtained with DS13D could be easily and accurately checked. Our goals have been three-fold: (1) To develop specialized mode-launching capabilities for single-mode signals typically found in test geometries and the diagnostics necessary to evaluate the performance of the code in modeling the propagation of those signals. (2) To analyze the effect of different zoning schemes on the accuracy with which the code models the propagation of signals through the geometries by checking against known analytic results and calculations performed with other codes. (3) To examine the effect of code modifications aimed at enhancing the accuracy of the simulations. The calculated transmission line impedance was chosen as the primary means of evaluating code performance. Since the lowest-order propagating modes for the test cases were transverse electromagnetic (TEM) modes, the computation of impedance was reasonably straightforward. Both time- and frequency-domain values (the latter obtained from the code output by post-processing with a discrete Fourier transform) were obtained and compared.
An Optimized Parallel FDTD Topology for Challenging Electromagnetic Simulations on Supercomputers
Directory of Open Access Journals (Sweden)
Shugang Jiang
2015-01-01
Full Text Available It may not be a challenge to run a Finite-Difference Time-Domain (FDTD code for electromagnetic simulations on a supercomputer with more than 10 thousands of CPU cores; however, to make FDTD code work with the highest efficiency is a challenge. In this paper, the performance of parallel FDTD is optimized through MPI (message passing interface virtual topology, based on which a communication model is established. The general rules of optimal topology are presented according to the model. The performance of the method is tested and analyzed on three high performance computing platforms with different architectures in China. Simulations including an airplane with a 700-wavelength wingspan, and a complex microstrip antenna array with nearly 2000 elements are performed very efficiently using a maximum of 10240 CPU cores.
Plasma-material interaction under simulated disruption conditions
International Nuclear Information System (INIS)
Arkhipov, N.I.; Bakhtin, V.P.; Safronov, V.M.; Toporkov, D.A.; Vasenin, S.G.; Wurz, H.; Zhitlukhin, A.M.
1995-01-01
Sudden evaporation of divertor plate surface under high heat load during tokamak plasma disruption instantaneously produces a vapor shield. The cloud of vaporized material prevents the divertor plates from the bulk of incoming energy flux and thus reduces the further material erosion. Dynamics and effectiveness of the vapor shield are studied experimentally at the 2MK-200 facility under simulated disruption conditions. (orig.)
Plasma-material interaction under simulated disruption conditions
Energy Technology Data Exchange (ETDEWEB)
Arkhipov, N.I. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Bakhtin, V.P. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Toporkov, D.A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Vasenin, S.G. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Wurz, H. [Kernforschungszentrum Karlsruhe, INR (Germany); Zhitlukhin, A.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation)
1995-12-31
Sudden evaporation of divertor plate surface under high heat load during tokamak plasma disruption instantaneously produces a vapor shield. The cloud of vaporized material prevents the divertor plates from the bulk of incoming energy flux and thus reduces the further material erosion. Dynamics and effectiveness of the vapor shield are studied experimentally at the 2MK-200 facility under simulated disruption conditions. (orig.).
Simulation of density measurements in plasma wakefields using photon acceleration
Directory of Open Access Journals (Sweden)
Muhammad Firmansyah Kasim
2015-03-01
Full Text Available One obstacle in plasma accelerator development is the limitation of techniques to diagnose and measure plasma wakefield parameters. In this paper, we present a novel concept for the density measurement of a plasma wakefield using photon acceleration, supported by extensive particle in cell simulations of a laser pulse that copropagates with a wakefield. The technique can provide the perturbed electron density profile in the laser’s reference frame, averaged over the propagation length, to be accurate within 10%. We discuss the limitations that affect the measurement: small frequency changes, photon trapping, laser displacement, stimulated Raman scattering, and laser beam divergence. By considering these processes, one can determine the optimal parameters of the laser pulse and its propagation length. This new technique allows a characterization of the density perturbation within a plasma wakefield accelerator.
Simulation of density measurements in plasma wakefields using photo acceleration
Kasim, Muhammad Firmansyah; Ceurvorst, Luke; Sadler, James; Burrows, Philip N; Trines, Raoul; Holloway, James; Wing, Matthew; Bingham, Robert; Norreys, Peter
2015-01-01
One obstacle in plasma accelerator development is the limitation of techniques to diagnose and measure plasma wakefield parameters. In this paper, we present a novel concept for the density measurement of a plasma wakefield using photon acceleration, supported by extensive particle in cell simulations of a laser pulse that copropagates with a wakefield. The technique can provide the perturbed electron density profile in the laser’s reference frame, averaged over the propagation length, to be accurate within 10%. We discuss the limitations that affect the measurement: small frequency changes, photon trapping, laser displacement, stimulated Raman scattering, and laser beam divergence. By considering these processes, one can determine the optimal parameters of the laser pulse and its propagation length. This new technique allows a characterization of the density perturbation within a plasma wakefield accelerator.
Advances in petascale kinetic plasma simulation with VPIC and Roadrunner
Energy Technology Data Exchange (ETDEWEB)
Bowers, Kevin J [Los Alamos National Laboratory; Albright, Brian J [Los Alamos National Laboratory; Yin, Lin [Los Alamos National Laboratory; Daughton, William S [Los Alamos National Laboratory; Roytershteyn, Vadim [Los Alamos National Laboratory; Kwan, Thomas J T [Los Alamos National Laboratory
2009-01-01
VPIC, a first-principles 3d electromagnetic charge-conserving relativistic kinetic particle-in-cell (PIC) code, was recently adapted to run on Los Alamos's Roadrunner, the first supercomputer to break a petaflop (10{sup 15} floating point operations per second) in the TOP500 supercomputer performance rankings. They give a brief overview of the modeling capabilities and optimization techniques used in VPIC and the computational characteristics of petascale supercomputers like Roadrunner. They then discuss three applications enabled by VPIC's unprecedented performance on Roadrunner: modeling laser plasma interaction in upcoming inertial confinement fusion experiments at the National Ignition Facility (NIF), modeling short pulse laser GeV ion acceleration and modeling reconnection in magnetic confinement fusion experiments.
Energy Technology Data Exchange (ETDEWEB)
Chen Ziyu; Chen Shi; Dan Jiakun; Li Jianfeng; Peng Qixian, E-mail: ziyuch@gmail.com [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China)
2011-10-15
A simple one-dimensional analytical model for electromagnetic emission from an unmagnetized wakefield excited by an intense short-pulse laser in the nonlinear regime has been developed in this paper. The expressions for the spectral and angular distributions of the radiation have been derived. The model suggests that the origin of the radiation can be attributed to the violent sudden acceleration of plasma electrons experiencing the accelerating potential of the laser wakefield. The radiation process could help to provide a qualitative interpretation of existing experimental results, and offers useful information for future laser wakefield experiments.
International Nuclear Information System (INIS)
Chen Ziyu; Chen Shi; Dan Jiakun; Li Jianfeng; Peng Qixian
2011-01-01
A simple one-dimensional analytical model for electromagnetic emission from an unmagnetized wakefield excited by an intense short-pulse laser in the nonlinear regime has been developed in this paper. The expressions for the spectral and angular distributions of the radiation have been derived. The model suggests that the origin of the radiation can be attributed to the violent sudden acceleration of plasma electrons experiencing the accelerating potential of the laser wakefield. The radiation process could help to provide a qualitative interpretation of existing experimental results, and offers useful information for future laser wakefield experiments.
Studies of the ablated plasma from experimental plasma gun disruption simulations
Energy Technology Data Exchange (ETDEWEB)
Rockett, P.D.; Hunter, J.A. [Sandia National Labs., Albuquerque, NM (United States); Bradley, J.T. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering
1994-07-01
Extensive simulations of Tokamak disruptions have provided a picture of material erosion that is limited by the transfer of energy from the incident plasma to the armor solid surface through a dense vapor shield. Radiation spectra were recorded in the VUV and in the visible at the Efremov Laboratories on VIKA using graphite targets. The VUV data were recorded with a Sandia Labs transmission grating spectrograph, covering 1--40 nm. Plasma parameters were evaluated with incident plasma energy densities varying from 1--10 kJ/cm{sup 2}. A second transmission grating spectrograph was taken to 2MK-200 at TRINITI to study the plasma-material interface in magnetic cusp plasma. Target materials included POCO graphite, ATJ graphite, boron nitride, and plasma-sprayed tungsten. Detailed spectra were recorded with a spatial resolution of {approximately}1 mm resolution. Time-resolved data with 40--200 ns resolution was also recorded. The data from both plasma gun facilities demonstrated that the hottest plasma region was sitting several millimeters above the armor tile surface.
International Nuclear Information System (INIS)
Yamashita, H.; Marinova, I.; Cingoski, V.
2002-01-01
These proceedings contain papers relating to the 3rd Japanese-Bulgarian-Macedonian Joint Seminar on Applied Electromagnetics. Included are the following groups: Numerical Methods I; Electrical and Mechanical System Analysis and Simulations; Inverse Problems and Optimizations; Software Methodology; Numerical Methods II; Applied Electromagnetics
Numerical simulation of primary cluster formation in silane plasmas
Gupta, N; Kroesen, G
2003-01-01
The usage of low-cost silicon-based solar cells is limited by their tendency to degrade on prolonged exposure to sunlight. Current research has indicated that the inclusion of nano-particles in the plasma-deposited film enhances its efficiency considerably. It is therefore essential to identify the plasma operating conditions such that nano-particles are formed and deposited in the film. The early stages of cluster formation, nucleation and coagulation are still open to experimental and theoretical investigation. In this paper, a simulation of the first stage of particle formation in capacitively coupled radio-frequency discharges in SiH sub 4 is attempted. A molecular dynamics based model has been set up to simulate one of the principal reaction pathways in cluster formation. This simulation model appears to produce valid and meaningful trends. Further studies are planned to explore the effect of other parameters and alternate pathways.
Nonlinear MHD simulations of spherical tokamak and helical plasmas
Energy Technology Data Exchange (ETDEWEB)
Hayashi, T.; Mizuguchi, N.; Miura, H.; Kanno, R.; Nakajima, N.; Okamoto, M. [National Inst. for Fusion Science, Toki, Gifu (Japan)
2002-11-01
Nonlinear magnetohydrodynamic (MHD) simulations on relaxation phenomena in a spherical tokamak and a helical plasma, including three-dimensional (3D) equilibrium computations, are executed in full toroidal geometries. For a spherical tokamak, two-step evolution of the medium-n ballooning instabilities and a successive excitation of an internal n=1 crash has been observed. A similar process has been observed in an actual tokamak experiment of TFTR. The process is compared with a previous simulation for another MHD activity that is called the internal reconnection event (IRE). Three dimensional equilibrium code HINT is modified to extend functions, by which an n=1 island structure used for the local island diverter (LID) experiment in the LHD device is analyzed in finite pressure equilibria. Nonlinear simulations are executed for LHD plasma and pressure deformation due to evolution of m=2/n=1 pressure driven mode is observed, which has larger growth rate and saturation level than medium-n ballooning modes. (author)
International Nuclear Information System (INIS)
Meziani, T.; Colpo, P.; Rossi, F.
2006-01-01
The magnetic pole enhanced inductively coupled source (MaPE-ICP) is an innovative low-pressure plasma source that allows for high plasma density and high plasma uniformity, as well as large-area plasma generation. This article presents an electrical characterization of this source, and the experimental measurements are compared to the results obtained after modeling the source by the equivalent circuit of the transformer. In particular, the method applied consists in performing a reverse electromagnetic modeling of the source by providing the measured plasma parameters such as plasma density and electron temperature as an input, and computing the total impedance seen at the primary of the transformer. The impedance results given by the model are compared to the experimental results. This approach allows for a more comprehensive refinement of the electrical model in order to obtain a better fitting of the results. The electrical characteristics of the system, and in particular the total impedance, were measured at the inductive coil antenna (primary of the transformer). The source was modeled electrically by a finite element method, treating the plasma as a conductive load and taking into account the complex plasma conductivity, the value of which was calculated from the electron density and electron temperature measurements carried out previously. The electrical characterization of the inductive excitation source itself versus frequency showed that the source cannot be treated as purely inductive and that the effect of parasitic capacitances must be taken into account in the model. Finally, considerations on the effect of the magnetic core addition on the capacitive component of the coupling are made
International Nuclear Information System (INIS)
Borges, E.M.
1991-01-01
Thermoelectric Electromagnetic (TEEM) Pumps can be used for controlling the fluid flow in the primary and secondary circuits of liquid metal cooled space nuclear reactor. In order to simulate and to evaluate the pumps performance, in steady-state, the computer program BEMTE has been developed to study the main operational parameters and to determine the system actuation point, for a given reactor operating power. The results for each stage of the program were satisfactory, compared to experimental data. The program shows to be adequate for the design and simulating of direct current electromagnetic pumps. (author)
Vinas, Adolfo F.; Moya, Pablo S.; Navarro, Roberto; Araneda, Jamie A.
2014-01-01
Two fundamental challenging problems of laboratory and astrophysical plasmas are the understanding of the relaxation of a collisionless plasmas with nearly isotropic velocity distribution functions and the resultant state of nearly equipartition energy density with electromagnetic plasma turbulence. Here, we present the results of a study which shows the role that higher-order-modes play in limiting the electromagnetic whistler-like fluctuations in a thermal and non-thermal plasma. Our main results show that for a thermal plasma the magnetic fluctuations are confined by regions that are bounded by the least-damped higher order modes. We further show that the zone where the whistler-cyclotron normal modes merges the electromagnetic fluctuations shifts to longer wavelengths as the beta(sub e) increases. This merging zone has been interpreted as the beginning of the region where the whistler-cyclotron waves losses their identity and become heavily damped while merging with the fluctuations. Our results further indicate that in the case of nonthermal plasmas, the higher-order modes do not confine the fluctuations due to the effective higher-temperature effects and the excess of suprathermal plasma particles. The analysis presented here considers the second-order theory of fluctuations and the dispersion relation of weakly transverse fluctuations, with wave vectors parallel to the uniform background magnetic field, in a finite temperature isotropic bi-Maxwellian and Tsallis-kappa-like magnetized electron-proton plasma. Our results indicate that the spontaneously emitted electromagnetic fluctuations are in fact enhanced over these quasi modes suggesting that such modes play an important role in the emission and absorption of electromagnetic fluctuations in thermal or quasi-thermal plasmas.
Simulating the effects of plasma disruption with a 1 MA current pulse in a coaxial test fixture
International Nuclear Information System (INIS)
Praeg, W.F.
1985-01-01
A test fixture for simulating plasma disruptions, comprising two coaxial cylinders, has been designed for use with Argonne's electromagnetic test facility FELIX. A pulsed power supply drives a half cycle sine wave current of 10 0 A through the test fixture generating fields of -1 . The coaxial structure is 140 cm long, has an outer cylinder with an OD of 78 cm and an inner cylinder with an OD of 8.3 cm. It is surrounded by the FELIX solenoid field of 1 T. This proposed upgrade of the FELIX facility should be useful for testing the effect of plasma disruption on First Wall-Blanket-Shield (FWBS) structures; a future upgrade of the solenoid field to 4 T will allow to simulate reactor conditions even better
Directory of Open Access Journals (Sweden)
D. V. Rose
2010-09-01
Full Text Available A 3D fully electromagnetic (EM model of the principal pulsed-power components of a high-current linear transformer driver (LTD has been developed. LTD systems are a relatively new modular and compact pulsed-power technology based on high-energy density capacitors and low-inductance switches located within a linear-induction cavity. We model 1-MA, 100-kV, 100-ns rise-time LTD cavities [A. A. Kim et al., Phys. Rev. ST Accel. Beams 12, 050402 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.050402] which can be used to drive z-pinch and material dynamics experiments. The model simulates the generation and propagation of electromagnetic power from individual capacitors and triggered gas switches to a radially symmetric output line. Multiple cavities, combined to provide voltage addition, drive a water-filled coaxial transmission line. A 3D fully EM model of a single 1-MA 100-kV LTD cavity driving a simple resistive load is presented and compared to electrical measurements. A new model of the current loss through the ferromagnetic cores is developed for use both in circuit representations of an LTD cavity and in the 3D EM simulations. Good agreement between the measured core current, a simple circuit model, and the 3D simulation model is obtained. A 3D EM model of an idealized ten-cavity LTD accelerator is also developed. The model results demonstrate efficient voltage addition when driving a matched impedance load, in good agreement with an idealized circuit model.
Plasma environment of Titan: a 3-D hybrid simulation study
Directory of Open Access Journals (Sweden)
S. Simon
2006-05-01
Full Text Available Titan possesses a dense atmosphere, consisting mainly of molecular nitrogen. Titan's orbit is located within the Saturnian magnetosphere most of the time, where the corotating plasma flow is super-Alfvénic, yet subsonic and submagnetosonic. Since Titan does not possess a significant intrinsic magnetic field, the incident plasma interacts directly with the atmosphere and ionosphere. Due to the characteristic length scales of the interaction region being comparable to the ion gyroradii in the vicinity of Titan, magnetohydrodynamic models can only offer a rough description of Titan's interaction with the corotating magnetospheric plasma flow. For this reason, Titan's plasma environment has been studied by using a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. The calculations are performed on a curvilinear simulation grid which is adapted to the spherical geometry of the obstacle. In the model, Titan's dayside ionosphere is mainly generated by solar UV radiation; hence, the local ion production rate depends on the solar zenith angle. Because the Titan interaction features the possibility of having the densest ionosphere located on a face not aligned with the ram flow of the magnetospheric plasma, a variety of different scenarios can be studied. The simulations show the formation of a strong magnetic draping pattern and an extended pick-up region, being highly asymmetric with respect to the direction of the convective electric field. In general, the mechanism giving rise to these structures exhibits similarities to the interaction of the ionospheres of Mars and Venus with the supersonic solar wind. The simulation results are in agreement with data from recent Cassini flybys.
Plasma environment of Titan: a 3-D hybrid simulation study
Directory of Open Access Journals (Sweden)
S. Simon
2006-05-01
Full Text Available Titan possesses a dense atmosphere, consisting mainly of molecular nitrogen. Titan's orbit is located within the Saturnian magnetosphere most of the time, where the corotating plasma flow is super-Alfvénic, yet subsonic and submagnetosonic. Since Titan does not possess a significant intrinsic magnetic field, the incident plasma interacts directly with the atmosphere and ionosphere. Due to the characteristic length scales of the interaction region being comparable to the ion gyroradii in the vicinity of Titan, magnetohydrodynamic models can only offer a rough description of Titan's interaction with the corotating magnetospheric plasma flow. For this reason, Titan's plasma environment has been studied by using a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. The calculations are performed on a curvilinear simulation grid which is adapted to the spherical geometry of the obstacle. In the model, Titan's dayside ionosphere is mainly generated by solar UV radiation; hence, the local ion production rate depends on the solar zenith angle. Because the Titan interaction features the possibility of having the densest ionosphere located on a face not aligned with the ram flow of the magnetospheric plasma, a variety of different scenarios can be studied. The simulations show the formation of a strong magnetic draping pattern and an extended pick-up region, being highly asymmetric with respect to the direction of the convective electric field. In general, the mechanism giving rise to these structures exhibits similarities to the interaction of the ionospheres of Mars and Venus with the supersonic solar wind. The simulation results are in agreement with data from recent Cassini flybys.
Methodology of modeling and measuring computer architectures for plasma simulations
Wang, L. P. T.
1977-01-01
A brief introduction to plasma simulation using computers and the difficulties on currently available computers is given. Through the use of an analyzing and measuring methodology - SARA, the control flow and data flow of a particle simulation model REM2-1/2D are exemplified. After recursive refinements the total execution time may be greatly shortened and a fully parallel data flow can be obtained. From this data flow, a matched computer architecture or organization could be configured to achieve the computation bound of an application problem. A sequential type simulation model, an array/pipeline type simulation model, and a fully parallel simulation model of a code REM2-1/2D are proposed and analyzed. This methodology can be applied to other application problems which have implicitly parallel nature.
Numerical simulation of laser filamentation in underdense plasma
International Nuclear Information System (INIS)
Yu Lichun; Chen Zhihua; Tu Qinfen
2000-01-01
Developing process of filamentation and effect of characteristic parameters in underdense plasma have been studied using numerical simulation method. Production and development of two-dimensional cylinder filamentation instability were presented clearly. The results indicate incidence laser intensity and plasma background density are important factors affecting convergent intensity. At the same time, it was showed that different laser wavelength or different electron background density could affect filamentation process. The results are consistent with theory and experiments of alien reports. It can provide reference for restraining filamentation
Domínguez, Macarena; Muñoz, Víctor; Valdivia, Juan Alejandro
2012-05-01
The propagation of circularly polarized electromagnetic waves along a constant background magnetic field in an electron-positron plasma is calculated by means of both a fluid and a kinetic theory treatment. In the fluid theory, relativistic effects are included in the particle motion, the wave field, and in the thermal motion by means of a function f, which depends only on the plasma temperature. In this work we analyze the consistency of the fluid results with those obtained from a kinetic treatment, based on the relativistic Vlasov equation. The corresponding kinetic dispersion relation is numerically studied for various temperatures, and results are compared with the fluid treatment. Analytic expressions for the Alfvén velocity are obtained for the fluid and kinetic models, and it is shown that, in the kinetic treatment, the Alfvén branch is suppressed for large temperatures.
2D full-wave simulation of waves in space and tokamak plasmas
Directory of Open Access Journals (Sweden)
Kim Eun-Hwa
2017-01-01
Full Text Available Simulation results using a 2D full-wave code (FW2D for space and NSTX fusion plasmas are presented. The FW2D code solves the cold plasma wave equations using the finite element method. The wave code has been successfully applied to describe low frequency waves in planetary magnetospheres (i.e., dipole geometry and the results include generation and propagation of externally driven ultra-low frequency waves via mode conversion at Mercury and mode coupling, refraction and reflection of internally driven field-aligned propagating left-handed electromagnetic ion cyclotron (EMIC waves at Earth. In this paper, global structure of linearly polarized EMIC waves is examined and the result shows such resonant wave modes can be localized near the equatorial plane. We also adopt the FW2D code to tokamak geometry and examine radio frequency (RF waves in the scape-off layer (SOL of tokamaks. By adopting the rectangular and limiter boundary, we compare the results with existing AORSA simulations. The FW2D code results for the high harmonic fast wave heating case on NSTX with a rectangular vessel boundary shows excellent agreement with the AORSA code.
2D full-wave simulation of waves in space and tokamak plasmas
Kim, Eun-Hwa; Bertelli, Nicola; Johnson, Jay; Valeo, Ernest; Hosea, Joel
2017-10-01
Simulation results using a 2D full-wave code (FW2D) for space and NSTX fusion plasmas are presented. The FW2D code solves the cold plasma wave equations using the finite element method. The wave code has been successfully applied to describe low frequency waves in planetary magnetospheres (i.e., dipole geometry) and the results include generation and propagation of externally driven ultra-low frequency waves via mode conversion at Mercury and mode coupling, refraction and reflection of internally driven field-aligned propagating left-handed electromagnetic ion cyclotron (EMIC) waves at Earth. In this paper, global structure of linearly polarized EMIC waves is examined and the result shows such resonant wave modes can be localized near the equatorial plane. We also adopt the FW2D code to tokamak geometry and examine radio frequency (RF) waves in the scape-off layer (SOL) of tokamaks. By adopting the rectangular and limiter boundary, we compare the results with existing AORSA simulations. The FW2D code results for the high harmonic fast wave heating case on NSTX with a rectangular vessel boundary shows excellent agreement with the AORSA code.
Early MIMD experience with a plasma physics simulation program on the CRAY X-MP
International Nuclear Information System (INIS)
Rhoades, C.E. Jr.
1986-02-01
This paper describes some early experience with converting a plasma physics simulation program to the CRAY X-MP, a current multiple instruction, multiple data (MIMD) computer consisting of two processors with architecture similar to that of the CRAY-1. The computer program used in this study is an all Fortran version of SELF, a two species, one space, two velocity, electromagnetic, Newtonian, particle in cell, plasma simulation code. The approach to converting SELF to use both processors of the CRAY X-MP is described in some detail. The resulting multiprocessor version of SELF is nearly a factor of two faster in real time than the single processor version. The multiprocessor version obtains 58.2+-.1 seconds of central processor time in 30+-.5 seconds of real time. For comparison, the CRAY-1 execution time if 74.5 seconds. For SELF, which is mostly scalar coding, the CRAY X-MP is about 2.5 times faster overall than the CRAY-1
Jung, Ho-Yeon; Kim, In-Ho; Jung, Hyung-Jo
2017-10-31
Cable structure is a major component of long-span bridges, such as cable-stayed and suspension bridges, and it transfers the main loads of bridges to the pylons. As these cable structures are exposed to continuous external loads, such as vehicle and wind loads, vibration control and continuous monitoring of the cable are required. In this study, an electromagnetic (EM) damper was designed and fabricated for vibration control and monitoring of the cable structure. EM dampers, also called regenerative dampers, consist of permanent magnets and coils. The electromagnetic force due to the relative motion between the coil and the permanent magnet can be used to control the vibration of the structure. The electrical energy can be used as a power source for the monitoring system. The effects of the design parameters of the damper were numerically analyzed and the damper was fabricated. The characteristics of the damper were analyzed with various external load changes. Finally, the vibration-control and energy-harvesting performances of the cable structure were evaluated through a hybrid simulation. The vibration-control and energy-harvesting performances for various loads were analyzed and the applicability to the cable structure of the EM damper was evaluated.
Directory of Open Access Journals (Sweden)
Ho-Yeon Jung
2017-10-01
Full Text Available Cable structure is a major component of long-span bridges, such as cable-stayed and suspension bridges, and it transfers the main loads of bridges to the pylons. As these cable structures are exposed to continuous external loads, such as vehicle and wind loads, vibration control and continuous monitoring of the cable are required. In this study, an electromagnetic (EM damper was designed and fabricated for vibration control and monitoring of the cable structure. EM dampers, also called regenerative dampers, consist of permanent magnets and coils. The electromagnetic force due to the relative motion between the coil and the permanent magnet can be used to control the vibration of the structure. The electrical energy can be used as a power source for the monitoring system. The effects of the design parameters of the damper were numerically analyzed and the damper was fabricated. The characteristics of the damper were analyzed with various external load changes. Finally, the vibration-control and energy-harvesting performances of the cable structure were evaluated through a hybrid simulation. The vibration-control and energy-harvesting performances for various loads were analyzed and the applicability to the cable structure of the EM damper was evaluated.
Simulation and testing of a micro electromagnetic energy harvester for self-powered system
Directory of Open Access Journals (Sweden)
Yiming Lei
2014-01-01
Full Text Available This paper describes a low cost and efficient electromagnetic vibration energy harvester (EVEH for a self-powered system. The EVEH consists of a resistant (copper spring, a permanent magnet (NdFeB35 and a wire-wound copper coil. The copper spring was fabricated by the laser precision cutting technology. A numerical model was adopted to analyze magnetic field distribution of a rectangle permanent magnet. The finite element (FEM soft ANSYS was used to simulate the mechanical properties of the system. The testing results show that the micro electromagnetic vibration energy harvester can generate the maximal power 205.38 μW at a resonance frequency of 124.2 Hz with an acceleration of 0.5 g (g = 9.8 ms−2 across a load the 265 Ω and a superior normalized power density (NPD of 456.5 μW cm−3 g−2. The magnetic field distribution of the permanent magnet was calculated to optimize geometric parameters of the coil. The proposed EVEH has a high efficiency with the lower cost.
SU-E-T-512: Electromagnetic Simulations of the Dielectric Wall Accelerator
International Nuclear Information System (INIS)
Uselmann, A; Mackie, T
2014-01-01
Purpose: To characterize and parametrically study the key components of a dielectric wall accelerator through electromagnetic modeling and particle tracking. Methods: Electromagnetic and particle tracking simulations were performed using a commercial code (CST Microwave Studio, CST Inc.) utilizing the finite integration technique. A dielectric wall accelerator consists of a series of stacked transmission lines sequentially fired in synchrony with an ion pulse. Numerous properties of the stacked transmission lines, including geometric, material, and electronic properties, were analyzed and varied in order to assess their impact on the transverse and axial electric fields. Additionally, stacks of transmission lines were simulated in order to quantify the parasitic effect observed in closely packed lines. Particle tracking simulations using the particle-in-cell method were performed on the various stacks to determine the impact of the above properties on the resultant phase space of the ions. Results: Examination of the simulation results show that novel geometries can shape the accelerating pulse in order to reduce the energy spread and increase the average energy of accelerated ions. Parasitic effects were quantified for various geometries and found to vary with distance from the end of the transmission line and along the beam axis. An optimal arrival time of an ion pulse relative to the triggering of the transmission lines for a given geometry was determined through parametric study. Benchmark simulations of single transmission lines agree well with published experimental results. Conclusion: This work characterized the behavior of the transmission lines used in a dielectric wall accelerator and used this information to improve them in novel ways. Utilizing novel geometries, we were able to improve the accelerating gradient and phase space of the accelerated particle bunch. Through simulation, we were able to discover and optimize design issues with the device at
Simulations of galaxy cluster collisions with a dark plasma component
Spethmann, Christian; Veermäe, Hardi; Sepp, Tiit; Heikinheimo, Matti; Deshev, Boris; Hektor, Andi; Raidal, Martti
2017-12-01
Context. Dark plasma is an intriguing form of self-interacting dark matter with an effective fluid-like behavior, which is well motivated by various theoretical particle physics models. Aims: We aim to find an explanation for an isolated mass clump in the Abell 520 system, which cannot be explained by traditional models of dark matter, but has been detected in weak lensing observations. Methods: We performed N-body smoothed particle hydrodynamics simulations of galaxy cluster collisions with a two component model of dark matter, which is assumed to consist of a predominant non-interacting dark matter component and a 10-40% mass fraction of dark plasma. Results: The mass of a possible dark clump was calculated for each simulation in a parameter scan over the underlying model parameters. In two higher resolution simulations shock-waves and Mach cones were observed to form in the dark plasma halos. Conclusions: By choosing suitable simulation parameters, the observed distributions of dark matter in both the Bullet cluster (1E 0657-558) and Abell 520 (MS 0451.5+0250) can be qualitatively reproduced. Movies associated to Figs. A.1 and A.2 are available at http://www.aanda.org
Low-noise electromagnetic δf particle-in-cell simulation of electron Bernstein waves
International Nuclear Information System (INIS)
Xiang Nong; Cary, John R.; Barnes, Daniel C.; Carlsson, John
2006-01-01
The conversion of the extraordinary (X) mode to an electron Bernstein wave (EBW) is one way to get rf energy into an overdense plasma. Analysis of this is complex, as the EBW is a fully kinetic wave, and so its linear propagation is described by an intractable integro-differential equation. Nonlinear effects cannot be calculated within this rubric at all. Full particle-in-cell (PIC) simulations cannot be used for these analyses, as the noise levels for reasonable simulation parameters are much greater than the typical rf amplitudes. It is shown that the delta-f computations are effective for this analysis. In particular, the accuracy of those computations has been verified by comparison with full PIC, cold plasma theory, and small gyroradius theory. This computational method is then used to analyze mode conversion in different frequency regimes. In particular, reasonable agreement with the theoretical predictions of Ram and Schultz [Phys. Plasmas 7, 4084 (2000)] in the linear regime is found, where 100% X-B mode conversion has been obtained when the driving frequency is less than twice the electron gyrofrequency. The results show that cold-plasma theory well predicts the mode conversion efficiency, as is consistent with the phase-space picture of mode conversion. From this it can be shown that nearly 100% X-B mode conversion cannot be obtained when the frequency is higher than the electron second harmonic cyclotron frequency
Schreyer, W.; Kikawa, T.; Losekamm, M. J.; Paul, S.; Picker, R.
2017-06-01
Modern precision experiments trapping low-energy particles require detailed simulations of particle trajectories and spin precession to determine systematic measurement limitations and apparatus deficiencies. We developed PENTrack, a tool that allows to simulate trajectories of ultracold neutrons and their decay products-protons and electrons-and the precession of their spins in complex geometries and electromagnetic fields. The interaction of ultracold neutrons with matter is implemented with the Fermi-potential formalism and diffuse scattering using Lambert and microroughness models. The results of several benchmark simulations agree with STARucn v1.2, uncovered several flaws in Geant4 v10.2.2, and agree with experimental data. Experiment geometry and electromagnetic fields can be imported from commercial computer-aided-design and finite-element software. All simulation parameters are defined in simple text files allowing quick changes. The simulation code is written in C++ and is freely available at github.com/wschreyer/PENTrack.git.
International Nuclear Information System (INIS)
Juhl, B.; Treumann, R.A.
1980-01-01
Observation of the adiabatic behaviour of energetic particle pitch-angle distributions in the magnetosphere (Lyons, 1977, and others) in the past indicated the development of pronounced minima or drift-loss cones on the pitch-angle distributions centred at α approx.= 90 0 in connection with storm-time changes in magnetospheric convection and magnetic field. Using a model of a drift-modified loss-cone distribution (MLCD) of the butterfly type, the linear stability of electromagnetic whistler or ion-cyclotron waves propagating parallel to the magnetic field has been investigated. The instability is shown to be quenched at high frequencies ω 0 are identified as generating electromagnetic cyclotron waves near the marginally stable frequency ωsub(m). It is concluded that the absence of electromagnetic VLF and ELF noise during times when MLCD develops is the result of the shift of the unstable spectrum to low frequencies. (orig.)
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.
Simulation of uranium and plutonium oxides compounds obtained in plasma
Novoselov, Ivan Yu.; Karengin, Alexander G.; Babaev, Renat G.
2018-03-01
The aim of this paper is to carry out thermodynamic simulation of mixed plutonium and uranium oxides compounds obtained after plasma treatment of plutonium and uranium nitrates and to determine optimal water-salt-organic mixture composition as well as conditions for their plasma treatment (temperature, air mass fraction). Authors conclude that it needs to complete the treatment of nitric solutions in form of water-salt-organic mixtures to guarantee energy saving obtainment of oxide compounds for mixed-oxide fuel and explain the choice of chemical composition of water-salt-organic mixture. It has been confirmed that temperature of 1200 °C is optimal to practice the process. Authors have demonstrated that condensed products after plasma treatment of water-salt-organic mixture contains targeted products (uranium and plutonium oxides) and gaseous products are environmental friendly. In conclusion basic operational modes for practicing the process are showed.
Implicit multi-fluid simulation of interpenetrating plasmas
International Nuclear Information System (INIS)
Rambo, P.W.; Denavit, J.
1992-01-01
A one dimensional simulation code for interpenetrating multi-component plasmas is presented. Separate fluid equations for multiple species and the Poisson equation for the electric field are solved implicitly to allow stable accurate solutions over a wide range of the time scale parameters ω p Δt and ν c Δt (ω p is the plasma frequency, ν c a typical collision frequency and Δt the time step). In regions where ω p Δt c Δt p Δt >>1 and/or ν c Δt>>1, the ambipolar and/or diffusion models are recovered. In regions of low collisionality, particles may be created and deleted which are followed using particle and cell techniques combined with scatter and drag due to collisions with the fluids. Applications of this code to interpenetrating laser generated plasmas are presented
GPU-advanced 3D electromagnetic simulations of superconductors in the Ginzburg–Landau formalism
Energy Technology Data Exchange (ETDEWEB)
Stošić, Darko; Stošić, Dušan; Ludermir, Teresa [Centro de Informática, Universidade Federal de Pernambuco, Av. Luiz Freire s/n, 50670-901, Recife, PE (Brazil); Stošić, Borko [Departamento de Estatística e Informática, Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros s/n, Dois Irmãos, 52171-900 Recife, PE (Brazil); Milošević, Milorad V., E-mail: milorad.milosevic@uantwerpen.be [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)
2016-10-01
Ginzburg–Landau theory is one of the most powerful phenomenological theories in physics, with particular predictive value in superconductivity. The formalism solves coupled nonlinear differential equations for both the electronic and magnetic responsiveness of a given superconductor to external electromagnetic excitations. With order parameter varying on the short scale of the coherence length, and the magnetic field being long-range, the numerical handling of 3D simulations becomes extremely challenging and time-consuming for realistic samples. Here we show precisely how one can employ graphics-processing units (GPUs) for this type of calculations, and obtain physics answers of interest in a reasonable time-frame – with speedup of over 100× compared to best available CPU implementations of the theory on a 256{sup 3} grid.
Geant4 electromagnetic physics for high statistic simulation of LHC experiments
Allison, J; Bagulya, A; Champion, C; Elles, S; Garay, F; Grichine, V; Howard, A; Incerti, S; Ivanchenko, V; Jacquemier, J; Maire, M; Mantero, A; Nieminen, P; Pandola, L; Santin, G; Sawkey, D; Schalicke, A; Urban, L
2012-01-01
An overview of the current status of electromagnetic physics (EM) of the Geant4 toolkit is presented. Recent improvements are focused on the performance of large scale production for LHC and on the precision of simulation results over a wide energy range. Significant efforts have been made to improve the accuracy without compromising of CPU speed for EM particle transport. New biasing options have been introduced, which are applicable to any EM process. These include algorithms to enhance and suppress processes, force interactions or splitting of secondary particles. It is shown that the performance of the EM sub-package is improved. We will report extensions of the testing suite allowing high statistics validation of EM physics. It includes validation of multiple scattering, bremsstrahlung and other models. Cross checks between standard and low-energy EM models have been performed using evaluated data libraries and reference benchmark results.
Numerical simulation of narrow bipolar electromagnetic pulses generated by thunderstorm discharges
Bochkov, E. I.; Babich, L. P.; Kutsyk, I. M.
2013-07-01
Using the concept of avalanche relativistic runaway electrons (REs), we perform numerical simulations of compact intracloud discharge (CID) as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-VHF range, called narrow bipolar pulses (NBPs). For several values of the field overvoltage and altitude at which the discharge develops, the numbers of seed electrons initiating the avalanche are evaluated, with which the calculated EMP characteristics are consistent with the measured NBP parameters. We note shortcomings in the hypothesis assuming participation of cosmic ray air showers in avalanche initiation. The discharge capable of generating NBPs produces REs in numbers close to those in the source of terrestrial γ-ray flashes (TGFs), which can be an argument in favor of a unified NBP and TGF source.
Numerical simulation of narrow bipolar electromagnetic pulses generated by thunderstorm discharges
International Nuclear Information System (INIS)
Bochkov, E. I.; Babich, L. P.; Kutsyk, I. M.
2013-01-01
Using the concept of avalanche relativistic runaway electrons (REs), we perform numerical simulations of compact intracloud discharge (CID) as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-VHF range, called narrow bipolar pulses (NBPs). For several values of the field overvoltage and altitude at which the discharge develops, the numbers of seed electrons initiating the avalanche are evaluated, with which the calculated EMP characteristics are consistent with the measured NBP parameters. We note shortcomings in the hypothesis assuming participation of cosmic ray air showers in avalanche initiation. The discharge capable of generating NBPs produces REs in numbers close to those in the source of terrestrial γ-ray flashes (TGFs), which can be an argument in favor of a unified NBP and TGF source
A Moving Window Technique in Parallel Finite Element Time Domain Electromagnetic Simulation
Energy Technology Data Exchange (ETDEWEB)
Lee, Lie-Quan; Candel, Arno; Ng, Cho; Ko, Kwok; /SLAC
2010-06-07
A moving window technique for the finite element time domain (FETD) method is developed to simulate the propagation of electromagnetic waves induced by the transit of a charged particle beam inside large and long structures. The window moving along with the beam in the computational domain adopts high-order finite-element basis functions through p refinement and/or a high-resolution mesh through h refinement so that a sufficient accuracy is attained with substantially reduced computational costs. Algorithms to transfer discretized fields from one mesh to another, which are the key to implementing a moving window in a finite-element unstructured mesh, are presented. Numerical experiments are carried out using the moving window technique to compute short-range wakefields in long accelerator structures. The results are compared with those obtained from the normal FETD method and the advantages of using the moving window technique are discussed.
FD_BH: a program for simulating electromagnetic waves from a borehole antenna
Ellefsen, Karl J.
2002-01-01
Program FD_BH is used to simulate the electromagnetic waves generated by an antenna in a borehole. The model representing the antenna may include metallic parts, a coaxial cable as a feed to the driving point, and resistive loading. The program is written in the C programming language, and the program has been tested on both the Windows and the UNIX operating systems. This Open-File Report describes • The contents and organization of the Zip file (section 2). • The program files, the installation of the program, the input files, and the execution of the program (section 3). • Address to which suggestions for improving the program may be sent (section 4).
International Nuclear Information System (INIS)
Lecompte, J.-C.; Buisson, Jacques.
1981-01-01
Neutronics and thermodynamics measuring devices realize the control and nuclear safety of the reactor and the core. They cause the emergency stop of the reactor if the informations given by the sensors are out of the normal operation tolerances. Defining and assuring a protection level sufficiently high against electromagnetic disturbances is essential for avoiding those measuring devices of giving erroneous indications in the environment where they are located. To obtain this result, one procceds according to the following three steps: a) In situ measurements of the ambient level of disturbances (oscilloscope analysis, statistical measurements). b) Measurement in laboratory of the immunity against the disturbances caused by every constituent of the device (electronic cables, connectors) and then the complete device. c) In situ simulation on the devices of the perturbations caused by the measured ambient level [fr
Zou, Yi
The present work involves the study of a simplified atomic system to gain better understanding of controlling and manipulating Rydberg-like systems. Detailed simulations of the classical hydrogen atom have been carried out using, first, the nonrelativistic Lorentz-Dirac classical equation of motion for a charged point particle under the action of a Coulombic binding force, plus applied radiation, then progressing to include the effects of the classical electromagnetic zero-point (ZP) radiation spectrum. This work has been carried out under the guide of the theory called stochastic electrodynamics (SED). Many applications involving atoms in excited Rydberg states can be developed, based on the work described here, to aid in carefully controlled thin film deposition, ion implantation, etching, and sputtering in micro and nanoelectronics, as well as optical instrumentation related applications, via applied electromagnetic fields. The improved simulation code for the long-term numerical integration of non-linear differential equations for tracking particles, should be helpful for a number of other closely related areas. Specifically, investigations into astronomy, including the Kepler problem treated in satellite and planetary orbit simulations in celestial mechanics, as well as problems in such areas as atomic and molecular dynamic studies, may well find benefit from the investigations here. As shown in the present study, very nonlinear behavior occurs for such Rydberg-like system, making a numerical study of the system nearly essential. Little of this work has been explored before in the literature. Resonances, rapid transitions, very long decay times, all influenced by applied radiation, are described and analyzed in detail here. Such results are expected to have significant bearing on recent experiments reported in the literature on "kicked Rydberg" atoms. Moreover, as reported here, the ZP field was included in very lengthy numerical simulations, resulting in a
Agglomeration processes in carbonaceous dusty plasmas, experiments and numerical simulations
International Nuclear Information System (INIS)
Dap, S; Hugon, R; De Poucques, L; Bougdira, J; Lacroix, D; Patisson, F
2010-01-01
This paper deals with carbon dust agglomeration in radio frequency acetylene/argon plasma. Two studies, an experimental and a numerical one, were carried out to model dust formation mechanisms. Firstly, in situ transmission spectroscopy of dust clouds in the visible range was performed in order to observe the main features of the agglomeration process of the produced carbonaceous dust. Secondly, numerical simulation tools dedicated to understanding the achieved experiments were developed. A first model was used for the discretization of the continuous population balance equations that characterize the dust agglomeration process. The second model is based on a Monte Carlo ray-tracing code coupled to a Mie theory calculation of dust absorption and scattering parameters. These two simulation tools were used together in order to numerically predict the light transmissivity through a dusty plasma and make comparisons with experiments.
TSC simulation of the ohmic discharges for the tokamak plasmas
International Nuclear Information System (INIS)
Li Jiaxian; Pan Yudong; Zhang Jihua
2010-01-01
TSC (Tokamak simulation Code) is a famous numerical simulation code in fusion research, which is developed by Princeton Plasma Physics Laboratory. The code has been used to provide the physics studies to support the design of the poloidal field system in the new tokamak in Southwestern of Institute of Physics (SWIP). These studies have been performed in some depth. We briefly summarize the analysis methods used, but concentrate on giving the key results. This work firstly confirmed the plasma configuration designed by the SWEQU and EFIT code. We presented the main results of standard ohmic discharge evolution of the new tokamak in SWIP. The real-time feedback control system has been combined which considering the plasma displacement control and the current control. The output physical parameters have been detailed analyzed in this thesis, which including the plasma magnetic axis evolution, current profile evoultion, loop voltage evolution, electron temperature profile evolution, ion temperature profile evolution, density profile, pressure profile and so on. These parameters may supply the benchmarch to future experimental diagnostic information. (authors)
Equilibrium statistical mechanics of strongly coupled plasmas by numerical simulation
International Nuclear Information System (INIS)
DeWitt, H.E.
1977-01-01
Numerical experiments using the Monte Carlo method have led to systematic and accurate results for the thermodynamic properties of strongly coupled one-component plasmas and mixtures of two nuclear components. These talks are intended to summarize the results of Monte Carlo simulations from Paris and from Livermore. Simple analytic expressions for the equation of state and other thermodynamic functions have been obtained in which there is a clear distinction between a lattice-like static portion and a thermal portion. The thermal energy for the one-component plasma has a simple power dependence on temperature, (kT)/sup 3 / 4 /, that is identical to Monte Carlo results obtained for strongly coupled fluids governed by repulsive l/r/sup n/ potentials. For two-component plasmas the ion-sphere model is shown to accurately represent the static portion of the energy. Electron screening is included in the Monte Carlo simulations using linear response theory and the Lindhard dielectric function. Free energy expressions have been constructed for one and two component plasmas that allow easy computation of all thermodynamic functions
Snelling, J. M.; Johnson, J.; Engebretson, M. J.; Kim, E. H.; Tian, S.
2017-12-01
While it is currently well accepted that the free energy for growth of electromagnetic ion cyclotron (EMIC) waves in Earth's magnetosphere comes from unstable configurations of hot anisotropic ions that are injected into the ring current, several questions remain about what controls the instability. A recent study of the occurrence of EMIC waves relative to the plasmapause in Vallen Probes Data showed that plasma density gradients or enhancements were not the dominant factor in determining the site of EMIC wave generation [Tetrick et al. 2017]. However, the factors that control wave growth on each of the branches are not fully understood. For example, in some cases, the measured anisotropy is not adequate to explain local instability, and the relative importance of the density and composition of a cold plasma population is still uncertain. Several intervals of EMIC wave activity are analyzed to determine the role of a cold population in driving instability on each of the wave branches. This study utilizes the WHAMP (Waves in Homogeneous Anisotropic Magnetized Plasma) stability code with plasma distributions optimized to fit the observed distributions including temperature anisotropy, loss cone, and ring beam populations.
Laser-Plasma Modeling Using PERSEUS Extended-MHD Simulation Code for HED Plasmas
Hamlin, Nathaniel; Seyler, Charles
2017-10-01
We discuss the use of the PERSEUS extended-MHD simulation code for high-energy-density (HED) plasmas in modeling the influence of Hall and electron inertial physics on laser-plasma interactions. By formulating the extended-MHD equations as a relaxation system in which the current is semi-implicitly time-advanced using the Generalized Ohm's Law, PERSEUS enables modeling of extended-MHD phenomena (Hall and electron inertial physics) without the need to resolve the smallest electron time scales, which would otherwise be computationally prohibitive in HED plasma simulations. We first consider a laser-produced plasma plume pinched by an applied magnetic field parallel to the laser axis in axisymmetric cylindrical geometry, forming a conical shock structure and a jet above the flow convergence. The Hall term produces low-density outer plasma, a helical field structure, flow rotation, and field-aligned current, rendering the shock structure dispersive. We then model a laser-foil interaction by explicitly driving the oscillating laser fields, and examine the essential physics governing the interaction. This work is supported by the National Nuclear Security Administration stewardship sciences academic program under Department of Energy cooperative agreements DE-FOA-0001153 and DE-NA0001836.
Parallel simulation of radio-frequency plasma discharges
International Nuclear Information System (INIS)
Fivaz, M.; Howling, A.; Ruegsegger, L.; Schwarzenbach, W.; Baeumle, B.
1994-01-01
The 1D Particle-In-Cell and Monte Carlo collision code XPDP1 is used to model radio-frequency argon plasma discharges. The code runs faster on a single-user parallel system called MUSIC than on a CRAY-YMP. The low cost of the MUSIC system allows a 24-hours-per-day use and the simulation results are available one to two orders of magnitude quicker than with a super computer shared with other users. The parallelization strategy and its implementation are discussed. Very good agreement is found between simulation results and measurements done in an experimental argon discharge. (author) 2 figs., 3 refs
PIC Simulation of Laser Plasma Interactions with Temporal Bandwidths
Tsung, Frank; Weaver, J.; Lehmberg, R.
2015-11-01
We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temperal bandwidths under conditions relevant to current and future shock ignition experiments on the NIKE laser. Our simulations show that, for sufficiently large bandwidth, the saturation level, and the distribution of hot electrons, can be effected by the addition of temporal bandwidths (which can be accomplished in experiments using smoothing techniques such as SSD or ISI). We will show that temporal bandwidth along play an important role in the control of LPI's in these lasers and discuss future directions. This work is conducted under the auspices of NRL.
Multigrid Particle-in-cell Simulations of Plasma Microturbulence
Energy Technology Data Exchange (ETDEWEB)
J.L.V. Lewandowski
2003-06-17
A new scheme to accurately retain kinetic electron effects in particle-in-cell (PIC) simulations for the case of electrostatic drift waves is presented. The splitting scheme, which is based on exact separation between adiabatic and on adiabatic electron responses, is shown to yield more accurate linear growth rates than the standard df scheme. The linear and nonlinear elliptic problems that arise in the splitting scheme are solved using a multi-grid solver. The multi-grid particle-in-cell approach offers an attractive path, both from the physics and numerical points of view, to simulate kinetic electron dynamics in global toroidal plasmas.
Computer simulation of kinetic properties of plasmas. Final report
International Nuclear Information System (INIS)
Denavit, J.
1982-08-01
The research was directed toward the development and testing of new numerical methods for particle and hybrid simulation of plasmas, and their application to physical problems of current significance to Magnetic Fusion Energy. This project will terminate on August 31, 1982 and this Final Report describes: (1) the research accomplished since the last renewal on October 1, 1981; and (2) a perspective of the work done since the beginning of the project in February 1972
Two-dimensional heat conducting simulation of plasma armatures
International Nuclear Information System (INIS)
Huerta, M.A.; Boynton, G.
1991-01-01
This paper reports on our development of a two-dimensional MHD code to simulate internal motions in a railgun plasma armature. The authors use the equations of resistive MHD, with Ohmic heating, and radiation heat transport. The authors use a Flux Corrected Transport code to advance all quantities in time. Our runs show the development of complex flows, subsequent shedding of secondary arcs, and a drop in the acceleration of the armature
A Computational Cluster for Advanced Plasma Physics Simulations
2010-02-08
were made amongst several cluster manufacturers, including Cray, IBM, Dell, Silicon Mechanics, Rackable Sytems , and SiCortex before deciding on the...simulated. The algorithm implements the discontinuous Galerkin method to achieve high-order accuracy and will use body -fitted computational meshes to...APS Poster’s work and ICC 2010 made use of the ICE cluster: 2009 APS: ”Plasma Solution Quality in Distorted, Body -Fitted Meshes in SEL/HiFi”, W
Energy Technology Data Exchange (ETDEWEB)
Ng, Cho; Akcelik, Volkan; Candel, Arno; Chen, Sheng; Ge, Lixin; Kabel, Andreas; Lee, Lie-Quan; Li, Zenghai; Prudencio, Ernesto; Schussman, Greg; Uplenchwar1, Ravi; Xiao1, Liling; Ko1, Kwok; Austin, T.; Cary, J.R.; Ovtchinnikov, S.; Smith, D.N.; Werner, G.R.; Bellantoni, L.; /SLAC /TechX Corp. /Fermilab
2008-08-01
SciDAC1, with its support for the 'Advanced Computing for 21st Century Accelerator Science and Technology' (AST) project, witnessed dramatic advances in electromagnetic (EM) simulations for the design and optimization of important accelerators across the Office of Science. In SciDAC2, EM simulations continue to play an important role in the 'Community Petascale Project for Accelerator Science and Simulation' (ComPASS), through close collaborations with SciDAC CETs/Institutes in computational science. Existing codes will be improved and new multi-physics tools will be developed to model large accelerator systems with unprecedented realism and high accuracy using computing resources at petascale. These tools aim at targeting the most challenging problems facing the ComPASS project. Supported by advances in computational science research, they have been successfully applied to the International Linear Collider (ILC) and the Large Hadron Collider (LHC) in High Energy Physics (HEP), the JLab 12-GeV Upgrade in Nuclear Physics (NP), as well as the Spallation Neutron Source (SNS) and the Linac Coherent Light Source (LCLS) in Basic Energy Sciences (BES).
International Nuclear Information System (INIS)
Ng, Cho; Akcelik, Volkan; Candel, Arno; Chen, Sheng; Ge, Lixin; Kabel, Andreas; Lee, Lie-Quan; Li, Zenghai; Prudencio, Ernesto; Schussman, Greg; Uplenchwar1, Ravi; Xiao1, Liling; Ko1, Kwok; Austin, T.; Cary, J.R.; Ovtchinnikov, S.; Smith, D.N.; Werner, G.R.; Bellantoni, L.; TechX Corp.; Fermilab
2008-01-01
SciDAC1, with its support for the 'Advanced Computing for 21st Century Accelerator Science and Technology' (AST) project, witnessed dramatic advances in electromagnetic (EM) simulations for the design and optimization of important accelerators across the Office of Science. In SciDAC2, EM simulations continue to play an important role in the 'Community Petascale Project for Accelerator Science and Simulation' (ComPASS), through close collaborations with SciDAC CETs/Institutes in computational science. Existing codes will be improved and new multi-physics tools will be developed to model large accelerator systems with unprecedented realism and high accuracy using computing resources at petascale. These tools aim at targeting the most challenging problems facing the ComPASS project. Supported by advances in computational science research, they have been successfully applied to the International Linear Collider (ILC) and the Large Hadron Collider (LHC) in High Energy Physics (HEP), the JLab 12-GeV Upgrade in Nuclear Physics (NP), as well as the Spallation Neutron Source (SNS) and the Linac Coherent Light Source (LCLS) in Basic Energy Sciences (BES)
International Nuclear Information System (INIS)
Ng, C; Akcelik, V; Candel, A; Chen, S; Ge, L; Kabel, A; Lee, Lie-Quan; Li, Z; Prudencio, E; Schussman, G; Uplenchwar, R; Xiao, L; Ko, K; Austin, T; Cary, J R; Ovtchinnikov, S; Smith, D N; Werner, G R; Bellantoni, L
2008-01-01
SciDAC-1, with its support for the 'Advanced Computing for 21st Century Accelerator Science and Technology' project, witnessed dramatic advances in electromagnetic (EM) simulations for the design and optimization of important accelerators across the Office of Science. In SciDAC2, EM simulations continue to play an important role in the 'Community Petascale Project for Accelerator Science and Simulation' (ComPASS), through close collaborations with SciDAC Centers and Insitutes in computational science. Existing codes will be improved and new multi-physics tools will be developed to model large accelerator systems with unprecedented realism and high accuracy using computing resources at petascale. These tools aim at targeting the most challenging problems facing the ComPASS project. Supported by advances in computational science research, they have been successfully applied to the International Linear Collider and the Large Hadron Collider in high energy physics, the JLab 12-GeV Upgrade in nuclear physics, and the Spallation Neutron Source and the Linac Coherent Light Source in basic energy sciences
Kenjeres, S.
2009-01-01
We conducted a large eddy simulation (LES) of a locally applied electromagnetic control of turbulent thermal convection of an electrically conductive fluid (electrolyte solution) inside of a slender enclosure. Generic configurations, consisting of two or three magnets of opposite polarities located
Hybrid simulation of electrode plasmas in high-power diodes
International Nuclear Information System (INIS)
Welch, Dale R.; Rose, David V.; Bruner, Nichelle; Clark, Robert E.; Oliver, Bryan V.; Hahn, Kelly D.; Johnston, Mark D.
2009-01-01
New numerical techniques for simulating the formation and evolution of cathode and anode plasmas have been successfully implemented in a hybrid code. The dynamics of expanding electrode plasmas has long been recognized as a limiting factor in the impedance lifetimes of high-power vacuum diodes and magnetically insulated transmission lines. Realistic modeling of such plasmas is being pursued to aid in understanding the operating characteristics of these devices as well as establishing scaling relations for reliable extrapolation to higher voltages. Here, in addition to kinetic and fluid modeling, a hybrid particle-in-cell technique is described that models high density, thermal plasmas as an inertial fluid which transitions to kinetic electron or ion macroparticles above a prescribed energy. The hybrid technique is computationally efficient and does not require resolution of the Debye length. These techniques are first tested on a simple planar diode then applied to the evolution of both cathode and anode plasmas in a high-power self-magnetic pinch diode. The impact of an intense electron flux on the anode surface leads to rapid heating of contaminant material and diode impedance loss.
Lardeau, Sylvain; Ferrari, Simone; Rossi, Lionel
2008-12-01
Three-dimensional (3D) direct numerical simulations of a flow driven by multiscale electromagnetic forcing are performed in order to reproduce with maximum accuracy the quasi-two-dimensional (2D) flow generated by the same multiscale forcing in the laboratory. The method presented is based on a 3D description of the flow and the electromagnetic forcing. Very good agreements between our simulations and the experiments are found both on velocity and acceleration field, this last comparison being, to our knowledge, done for the first time. Such agreement requires that both experiments and simulations are carefully performed and, more importantly, that the underlying simplification to model the experiments and the multiscale electromagnetic forcing do not introduce significant errors. The results presented in this paper differ significantly from previous 2D direct numerical simulation in which a classical linear Rayleigh friction modeling term was used to mimic the effect of the wall-normal friction. Indeed, purely 2D simulations are found to underestimate the Reynolds number and, due to the dominance of nonhomogeneous bottom friction, lead to the wrong physical mechanism. For the range of conditions presented in this paper, the Reynolds number, defined by the ratio between acceleration and viscous terms, remains the order of unity, and the Hartmann number, defined by the ratio between electromagnetic force terms and viscous terms, is about 2. The main conclusion is that 3D simulations are required to model the (3D) electromagnetic forces and the wall-normal shear. Indeed, even if the flow is quasi-2D in terms of energy, a full 3D approach is required to simulate these shallow layer flows driven by multiscale electromagnetic forcing. In the range of forcing intensity investigated in this paper, these multiscale flows remain quasi-2D, with negligible energy in the wall-normal velocity component. It is also shown that the driving terms are the electromagnetic forcing and
Electromagnetic simulators for Ground Penetrating Radar applications developed in COST Action TU1208
Pajewski, Lara; Giannopoulos, Antonios; Warren, Craig; Antonijevic, Sinisa; Doric, Vicko; Poljak, Dragan
2017-04-01
Founded in 1971, COST (European COoperation in Science and Technology) is the first and widest European framework for the transnational coordination of research activities. It operates through Actions, science and technology networks with a duration of four years. The main objective of the COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (4 April 2013 - 3 October 2017) is to exchange and increase knowledge and experience on Ground-Penetrating Radar (GPR) techniques in civil engineering, whilst promoting in Europe a wider use of this technique. Research activities carried out in TU1208 include all aspects of the GPR technology and methodology: design, realization and testing of radar systems and antennas; development and testing of surveying procedures for the monitoring and inspection of structures; integration of GPR with other non-destructive testing approaches; advancement of electromagnetic-modelling, inversion and data-processing techniques for radargram analysis and interpretation. GPR radargrams often have no resemblance to the subsurface or structures over which the profiles were recorded. Various factors, including the innate design of the survey equipment and the complexity of electromagnetic propagation in composite scenarios, can disguise complex structures recorded on reflection profiles. Electromagnetic simulators can help to understand how target structures get translated into radargrams. They can show the limitations of GPR technique, highlight its capabilities, and support the user in understanding where and in what environment GPR can be effectively used. Furthermore, electromagnetic modelling can aid the choice of the most proper GPR equipment for a survey, facilitate the interpretation of complex datasets and be used for the design of new antennas. Electromagnetic simulators can be employed to produce synthetic radargrams with the purposes of testing new data-processing, imaging and inversion algorithms, or assess
In situ electromagnetic field diagnostics with an electron plasma in a Penning-Malmberg trap
Amole, C; Baquero-Ruiz, M.; Bertsche, W.; Butler, E.; Capra, A.; Cesar, C.L.; Charlton, M.; Deller, A.; Evetts, N.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M.C.; Gill, D.R.; Gutierrez, A.; Hangst, J.S.; Hardy, W.N.; Hayden, M.E.; Isaac, C.A.; Jonsell, S.; Kurchaninov, L.; Little, A.; Madsen, N.; McKenna, J.T.K.; Menary, S.; Napoli, S.C.; Olchanski, K.; Olin, A.; Pusa, P.; Rasmussen, C.; Robicheaux, F.; Sarid, E.; Silveira, D.M.; So, C.; Stracka, S.; Tharp, T.; Thompson, R.I.; van der Werf, D.P.; Wurtele, J.S.
2014-01-01
We demonstrate a novel detection method for the cyclotron resonance frequency of an electron plasma in a Penning-Malmberg trap. With this technique, the electron plasma is used as an in situ diagnostic tool for measurement of the static magnetic field and the microwave electric field in the trap. The cyclotron motion of the electron plasma is excited by microwave radiation and the temperature change of the plasma is measured non-destructively by monitoring the plasma's quadrupole mode frequency. The spatially-resolved microwave electric field strength can be inferred from the plasma temperature change and the magnetic field is found through the cyclotron resonance frequency. These measurements were used extensively in the recently reported demonstration of resonant quantum interactions with antihydrogen.
Plasma theory and simulation. Quarterly progress report I, II, January 1-June 30, 1984
International Nuclear Information System (INIS)
Birdsall, C.K.
1984-01-01
Our group uses theory and simulation as tools in order to increase the understanding of instabilities, heating, transport, and other phenomena in plasmas. We also work on the improvement of simulation both theoretically and practically. Research in plasma theory and simulation has centered on the following: (1) electron Bernstein wave investigations; (2) simulation of plasma-sheath region, including ion reflection; (3) single ended plasma device, general behavior dc or ac; (4) single ended plasma device, unstable states; (5) corrections to time-independent Q-machine equilibria; (6) multifluid derivation of the Alfven ion-cyclotron linear dispersion relation; and (7) potential barrier between hot and cool plasmas
International Nuclear Information System (INIS)
Horioka, Kazuhiko
2002-06-01
The papers presented at the symposium on ''Physics and application of high energy density plasmas, held December 20-21, 2001 at NIFS'' are collected in this proceedings. The topics covered in the meeting include dense z-pinches, plasma focus, intense charged particle beams, intense radiation sources, discharge pumped X-ray lasers, their diagnostics, and applications of them. The papers reflect the present status and trends in the research field of high energy density plasmas. (author)
Numerical simulation of collision-free plasma using Vlasov hybrid simulation
International Nuclear Information System (INIS)
Nunn, D.
1990-01-01
A novel scheme for the numerical simulation of wave particle interactions in space plasmas has been developed. The method, termed VHS or Vlasov Hybrid Simulation, is applicable to hot collision free plasmas in which the unperturbed distribution functions is smooth and free of delta function singularities. The particle population is described as a continuous Vlasov fluid in phase space-granularity and collisional effects being ignored. In traditional PIC/CIC codes the charge/current due to each simulation particle is assigned to a fixed spatial grid. In the VHS method the simulation particles sample the Vlasov fluid and provide information about the value of distribution function (F(r,v) at random points in phase space. Values of F are interpolated from the simulation particles onto a fixed grid in velocity/position or phase space. With distribution function defined on a phase space grid the plasma charge/current field is quickly calculated. The simulation particles serve only to provide information, and thus the particle population may be dynamic. Particles no longer resonant with the wavefield may be discarded from the simulation, and new particles may be inserted into the Vlasov fluid where required
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)
International Nuclear Information System (INIS)
Ding Lei; Lai Yuan; He Bin
2005-01-01
It is of importance to localize neural sources from scalp recorded EEG. Low resolution brain electromagnetic tomography (LORETA) has received considerable attention for localizing brain electrical sources. However, most such efforts have used spherical head models in representing the head volume conductor. Investigation of the performance of LORETA in a realistic geometry head model, as compared with the spherical model, will provide useful information guiding interpretation of data obtained by using the spherical head model. The performance of LORETA was evaluated by means of computer simulations. The boundary element method was used to solve the forward problem. A three-shell realistic geometry (RG) head model was constructed from MRI scans of a human subject. Dipole source configurations of a single dipole located at different regions of the brain with varying depth were used to assess the performance of LORETA in different regions of the brain. A three-sphere head model was also used to approximate the RG head model, and similar simulations performed, and results compared with the RG-LORETA with reference to the locations of the simulated sources. Multi-source localizations were discussed and examples given in the RG head model. Localization errors employing the spherical LORETA, with reference to the source locations within the realistic geometry head, were about 20-30 mm, for four brain regions evaluated: frontal, parietal, temporal and occipital regions. Localization errors employing the RG head model were about 10 mm over the same four brain regions. The present simulation results suggest that the use of the RG head model reduces the localization error of LORETA, and that the RG head model based LORETA is desirable if high localization accuracy is needed
Edge-relevant plasma simulations with the continuum code COGENT
Dorf, M.; Dorr, M.; Ghosh, D.; Hittinger, J.; Rognlien, T.; Cohen, R.; Lee, W.; Schwartz, P.
2016-10-01
We describe recent advances in cross-separatrix and other edge-relevant plasma simulations with COGENT, a continuum gyro-kinetic code being developed by the Edge Simulation Laboratory (ESL) collaboration. The distinguishing feature of the COGENT code is its high-order finite-volume discretization methods, which employ arbitrary mapped multiblock grid technology (nearly field-aligned on blocks) to handle the complexity of tokamak divertor geometry with high accuracy. This paper discusses the 4D (axisymmetric) electrostatic version of the code, and the presented topics include: (a) initial simulations with kinetic electrons and development of reduced fluid models; (b) development and application of implicit-explicit (IMEX) time integration schemes; and (c) conservative modeling of drift-waves and the universal instability. Work performed for USDOE, at LLNL under contract DE-AC52-07NA27344 and at LBNL under contract DE-AC02-05CH11231.
Electromagnetic Simulations of Ground-Penetrating Radar Propagation near Lunar Pits and Lava Tubes
Zimmerman, M. I.; Carter, L. M.; Farrell, W. M.; Bleacher, J. E.; Petro, N. E.
2013-01-01
Placing an Orion capsule at the Earth-Moon L2 point (EML2) would potentially enable telerobotic operation of a rover on the lunar surface. The Human Exploration Virtual Institute (HEVI) is proposing that rover operations be carried out near one of the recently discovered lunar pits, which may provide radiation shielding for long duration human stays as well as a cross-disciplinary, science-rich target for nearer-term telerobotic exploration. Ground penetrating radar (GPR) instrumentation included onboard a rover has the potential to reveal many details of underground geologic structures near a pit, as well as characteristics of the pit itself. In the present work we employ the full-wave electromagnetic code MEEP to simulate such GPR reflections from a lunar pit and other subsurface features including lava tubes. These simulations will feed forward to mission concepts requiring knowledge of where to hide from harmful radiation and other environmental hazards such as plama charging and extreme diurnal temperatures.
Energy Technology Data Exchange (ETDEWEB)
Figueroa, Aldo [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209 (Mexico); Meunier, Patrice; Villermaux, Emmanuel [Aix-Marseille Univ., CNRS, Centrale Marseille, IRPHE, Marseille F-13384 (France); Cuevas, Sergio; Ramos, Eduardo [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, A.P. 34, Temixco, Morelos 62580 (Mexico)
2014-01-15
We present a combination of experiment, theory, and modelling on laminar mixing at large Péclet number. The flow is produced by oscillating electromagnetic forces in a thin electrolytic fluid layer, leading to oscillating dipoles, quadrupoles, octopoles, and disordered flows. The numerical simulations are based on the Diffusive Strip Method (DSM) which was recently introduced (P. Meunier and E. Villermaux, “The diffusive strip method for scalar mixing in two-dimensions,” J. Fluid Mech. 662, 134–172 (2010)) to solve the advection-diffusion problem by combining Lagrangian techniques and theoretical modelling of the diffusion. Numerical simulations obtained with the DSM are in reasonable agreement with quantitative dye visualization experiments of the scalar fields. A theoretical model based on log-normal Probability Density Functions (PDFs) of stretching factors, characteristic of homogeneous turbulence in the Batchelor regime, allows to predict the PDFs of scalar in agreement with numerical and experimental results. This model also indicates that the PDFs of scalar are asymptotically close to log-normal at late stages, except for the large concentration levels which correspond to low stretching factors.
RELATIVISTIC CYCLOTRON INSTABILITY IN ANISOTROPIC PLASMAS
Energy Technology Data Exchange (ETDEWEB)
López, Rodrigo A.; Moya, Pablo S.; Muñoz, Víctor; Valdivia, J. Alejandro [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Navarro, Roberto E.; Araneda, Jaime A. [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Viñas, Adolfo F., E-mail: rlopez186@gmail.com [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, MD 20771 (United States)
2016-11-20
A sufficiently large temperature anisotropy can sometimes drive various types of electromagnetic plasma micro-instabilities, which can play an important role in the dynamics of relativistic pair plasmas in space, astrophysics, and laboratory environments. Here, we provide a detailed description of the cyclotron instability of parallel propagating electromagnetic waves in relativistic pair plasmas on the basis of a relativistic anisotropic distribution function. Using plasma kinetic theory and particle-in-cell simulations, we study the influence of the relativistic temperature and the temperature anisotropy on the collective and noncollective modes of these plasmas. Growth rates and dispersion curves from the linear theory show a good agreement with simulations results.
Computation of laminar heat transfer from gaseous plasmas in electromagnetic fields
Bose, T. K.
1972-01-01
Heat transfer analysis procedure is presented for two-temperature gaseous plasma. Analysis is based on laminar flow of singly-ionized, quasineutral plasma with variable properties. Sheath analysis is described for species in accelerating field, decelerating field, emitted from wall, and recombining at wall.
The simulation of plasma double-layer structures
International Nuclear Information System (INIS)
Borovsky, J.E.; Joyce, G.
1982-01-01
Electrostatic plasma double layers are numerically simulated by means of a magnetized 2 1/2-dimensional particle-in-cell method. The investigation of planar double layers indicates that these one-dimensional potential structures are susceptible to periodic disruption by instabilities in the low-potential plasmas. Only a slight increase in the double-layer thickness with an increase in its obliqueness to the magnetic field is observed. Weak magnetization results in the double-layer electric field alignment of accelerated particles and strong magnetization results in their magnetic field alignment. The numerical simulations of spatially periodic two-dimensional double layers also exhibit cyclical instability. A morphological invariance in two-dimensional double layers with respect to the degree of magnetization implies that the potential structures scale with Debye lengths rather than with gyroradii. Electron-beam excited electrostatic electron-cyclotron waves and (ion-beam driven) solitary waves are present in the plasmas adjacent to the double layers. (Auth.)
Theory and simulation of anode spots in low pressure plasmas
Scheiner, Brett; Barnat, Edward V.; Baalrud, Scott D.; Hopkins, Matthew M.; Yee, Benjamin T.
2017-11-01
When electrodes are biased above the plasma potential, electrons accelerated through the associated electron sheath can dramatically increase the ionization rate of neutrals near the electrode surface. It has previously been observed that if the ionization rate is great enough, a double layer separates a luminous high-potential plasma attached to the electrode surface (called an anode spot or fireball) from the bulk plasma. Here, results of the first 2D particle-in-cell simulations of anode spot formation are presented along with a theoretical model describing the formation process. It is found that ionization leads to the build-up of an ion-rich layer adjacent to the electrode, forming a narrow potential well near the electrode surface that traps electrons born from ionization. It is shown that anode spot onset occurs when a quasineutral region is established in the potential well and the density in this region becomes large enough to violate the steady-state Langmuir condition, which is a balance between electron and ion fluxes across the double layer. A model for steady-state properties of the anode spot is also presented, which predicts values for the anode spot size, double layer potential drop, and form of the sheath at the electrode by considering particle, power, and current balance. These predictions are found to be consistent with the presented simulation and previous experiments.
Energy Technology Data Exchange (ETDEWEB)
Faugeras, P.E. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires. Groupe de recherches sur la fusion controlee
1967-07-01
The problem of the scattering of plane electromagnetic waves from a non-uniform, cylindrically symmetrical plasma is solved analytically, by a self-consistent field method, for a wave with the electric field parallel to the cylinder axis. Numerical results for the diffracted field are plotted for interesting ranges of the parameters involved: diameter, density on the axis, radial profile of the density, and collision frequencies. The case where the incident field is cylindric (waves surfaces parallel to the cylinder axis) is examined - this permits to connect theoretical calculations and experimental diffraction patterns, and also to explain the diffraction effects observed in a classical microwave interferometry experiment. These results, and the possibility of measuring exactly the diffracted field (showed by experiments with dielectric and metallic rods) lead to a new plasma diagnostic method, based on the diffraction, which has no theoretical limitations and it usable when the classical free-space wave methods are not (plasma diameter lower than 10 wave lengths). The feasibility of this method is tested with a plasma at atmospheric pressure and a 2 mm incident wavelength. The plasma is obtained by the laminar flow of a plasma torch, with a working gas (He or Ar) seeded by potassium (density continuously variable between 10{sup 11} and 10{sup 15} e/cm{sup 3}. Some diffraction patterns by this plasma and for various incident waves, are also given and explained with theoretical calculations. (author) [French] On etudie la diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene par une methode de champ self-consistant, et pour une onde de vecteur electrique parallele a l'axe du cylindre. On a calcule le champ diffracte en faisant varier le diametre du cylindre, la densite sur l'axe, le profil de densite et les frequences de collisions, et on donne ici les principaux resultats. On examine ensuite le cas d'une onde
Electromagnetic radiation emitted by a plasma produced in air by laser pulses with lambda = 10.6 μm
International Nuclear Information System (INIS)
Danilychev, V.A.; Zvorykin, V.D.; Kholin, I.V.; Chugunov, A.Y.
1981-01-01
The spectrum, brightness, and energy have been measured for the electromagnetic radiation emitted by a plasma produced in air near a solid surface by pulses from a high-power CO 2 laser. The air pressure was varied over the range p 0 = 0.1--760 torr, and the laser power density was varied over the range q = 5 x 10 6 --10 8 W/cm 2 . At p 0 > or approx. =2--5 torr the radiation properties of the plasma are determined by a laser-beam absorption wave which arises in the gas. The maximum brightness temperature, T/sub b/approx. =50 000 K (lambda = 400 +- 20 nm), is reached at p 0 = 25 torr. The emission spectrum is quite different from an equilibrium spectrum, consisting primarily of NII, OII, and NIII lines. The total energy radiation by the plasma in the wavelength interval 360--2600 nm into a solid angle of 4π sr reaches 2.3% of the laser pulse energy
International Nuclear Information System (INIS)
Shvets, Gennady; Kaganovich, Igor; Startsev, Edward
2002-01-01
In a recent Letter, Cheng et al. calculated/predicted several new effects: that (a) fraction of the short laser pulse momentum can be imparted to plasma electrons via collisional damping of the laser, thereby exciting a long-lived (longer than an oscillation period) plasma wave, which (b) gives rise to a spatially uniform dipole moment of a plasma, which (c) emits far-field narrow-band radiation at the plasma frequency omega subscript ''p'' over the recombination time of the plasma. We claim that the calculation of the effect (a) is in error and the predicted effects (b,c) do not occur as described. In fact, predicted narrow-band emission at omega subscript ''p'' would not occur even if the momentum transfer and the dipole excitation were calculated correctly
Electromagnetic diagnostics of ECR-Ion Sources plasmas: optical/X-ray imaging and spectroscopy
Mascali, D.; Castro, G.; Altana, C.; Caliri, C.; Mazzaglia, M.; Romano, F. P.; Leone, F.; Musumarra, A.; Naselli, E.; Reitano, R.; Torrisi, G.; Celona, L.; Cosentino, L. G.; Giarrusso, M.; Gammino, S.
2017-12-01
Magnetoplasmas in ECR-Ion Sources are excited from gaseous elements or vapours by microwaves in the range 2.45-28 GHz via Electron Cyclotron Resonance. A B-minimum, magnetohydrodynamic stable configuration is used for trapping the plasma. The values of plasma density, temperature and confinement times are typically ne= 1011-1013 cm-3, 01 eVelectromagnetic emission of such plasmas, in the optical/X-ray domain. Fast Silicon Drift detectors with high energy resolution of 125 eV at 5.9 keV have been used for the characterization of plasma emission at 02atoms/molecules in the plasmas have been measured for different values of neutral pressure, microwave power and magnetic field profile (they are critical for high-power proton sources).
International Nuclear Information System (INIS)
Avitzour, Yoav; Shvets, Gennady
2008-01-01
A new approach to manipulating the duration and frequency of microwave pulses using magnetized plasmas is demonstrated. The plasma accomplishes two functions: (i) slowing down and spatially compressing the incident wave, and (ii) modifying the propagation properties (group velocity and frequency) of the wave in the plasma during a uniform in space adiabatic in time variation of the magnitude and/or direction of the magnetic field. The increase in the group velocity results in the shortening of the temporal pulse duration. Depending on the plasma parameters, the frequency of the outgoing compressed pulse can either change or remain unchanged. Such dynamic manipulation of radiation in plasma opens new avenues for manipulating high power microwave pulses
Three dimensional simulation study of spheromak injection into magnetized plasmas
International Nuclear Information System (INIS)
Suzuki, Y.; Watanabe, T.H.; Sato, T.; Hayashi, T.
2000-01-01
The three dimensional dynamics of a spheromak-like compact toroid (SCT) plasmoid, which is injected into a magnetized target plasma region, is investigated by using MHD numerical simulations. It is found that the process of SCT penetration into this region is much more complicated than that which has been analysed so far by using a conducting sphere (CS) model. The injected SCT suffers from a tilting instability, which grows with a similar timescale to that of the SCT penetration. The instability is accompanied by magnetic reconnection between the SCT magnetic field and the target magnetic field, which disrupts the magnetic configuration of the SCT. Magnetic reconnection plays a role in supplying the high density plasma, initially confined in the SCT magnetic field, to the target region. The penetration depth of the SCT high density plasma is also examined. It is shown to be shorter than that estimated from the CS model. The SCT high density plasma is decelerated mainly by the Lorentz force of the target magnetic field, which includes not only the magnetic pressure force but also the magnetic tension force. Furthermore, by comparing the SCT plasmoid injection with the bare plasmoid injection, magnetic reconnection is considered to relax the magnetic tension force, i.e. the deceleration of the SCT plasmoid. (author)
The Integrated Plasma Simulator: A Flexible Python Framework for Coupled Multiphysics Simulation
Energy Technology Data Exchange (ETDEWEB)
Foley, Samantha S [ORNL; Elwasif, Wael R [ORNL; Bernholdt, David E [ORNL
2011-11-01
High-fidelity coupled multiphysics simulations are an increasingly important aspect of computational science. In many domains, however, there has been very limited experience with simulations of this sort, therefore research in coupled multiphysics often requires computational frameworks with significant flexibility to respond to the changing directions of the physics and mathematics. This paper presents the Integrated Plasma Simulator (IPS), a framework designed for loosely coupled simulations of fusion plasmas. The IPS provides users with a simple component architecture into which a wide range of existing plasma physics codes can be inserted as components. Simulations can take advantage of multiple levels of parallelism supported in the IPS, and can be controlled by a high-level ``driver'' component, or by other coordination mechanisms, such as an asynchronous event service. We describe the requirements and design of the framework, and how they were implemented in the Python language. We also illustrate the flexibility of the framework by providing examples of different types of simulations that utilize various features of the IPS.
International Nuclear Information System (INIS)
Jordan, T.
1996-01-01
Some aspects concerning the coupling of quasi-stationary electromagnetics and the dynamics of structure and fluid are investigated. The necessary equations are given in a dimensionless form. The dimensionless parameters in these equations are used to evaluate the importance of the different coupling effects. A finite element formulation of the eddy-current damping in solid structures is developed. With this formulation, an existing finite element method (FEM) structural dynamics code is extended and coupled to an FEM eddy-current code. With this program system, the influence of the eddy-current damping on the dynamic loading of the dual coolant blanket during a centered plasma disruption is determined. The analysis proves that only in loosely fixed or soft structures will eddy-current damping considerably reduce the resulting stresses. Additionally, the dynamic behavior of the liquid metal in the blankets' poloidal channels is described with a simple two-dimensional magnetohydrodynamic approach. The analysis of the dimensionless parameters shows that for small-scale experiments, which are designed to model the coupled electromagnetic and structural/fluid dynamic effects in such a blanket, the same magnetic fields must be applied as in the real fusion device. This will be the easiest way to design experiments that produce transferable results. 10 refs., 7 figs
Guo, Dawei; Cheng, Mousen; Li, Xiaokang
2017-10-01
In support of our planar pulsed inductive plasma thruster research, a fast electromagnetic inductive valve for a gas propellant injection system has been built and tested. A new and important design feature is the use of a conical diaphragm as the action part, which greatly contributes to the virtue of simplicity for adopting the resultant force of the diaphragm deformation as the closing force. An optical transmission technique is adopted to measure the opening and closing characters of the valve while the gas throughput is determined by measuring the pressure change per pulse in a test chamber with a capacitance manometer. The experimental results revealed that the delay time before the valve reaction is less than 40 μs, and the valve pulse width is no longer than 160 μs full width at half maximum. The valve delivers 0-2.5 mg of argon gas per pulse varied by adjusting the drive voltage and gas pressure.
Chaos in reversed-field-pinch plasma simulation and experiment
International Nuclear Information System (INIS)
Watts, C.; Newman, D.E.; Sprott, J.C.
1994-01-01
We investigate the possibility that chaos and simple determinism are governing the dynamics of reversed-field-pinch (RFP) plasmas using data from both numerical simulations and experiment. A large repertoire of nonlinear-analysis techniques is used to identify low-dimensional chaos. These tools include phase portraits and Poincare sections, correlation dimension, the spectrum of Lyapunov exponents, and short-term predictability. In addition, nonlinear-noise-reduction techniques are applied to the experimental data in an attempt to extract any underlying deterministic dynamics. Two model systems are used to simulate the plasma dynamics. These are the DEBS computer code, which models global RFP dynamics, and the dissipative trapped-electron-mode model, which models drift-wave turbulence. Data from both simulations show strong indications of low-dimensional chaos and simple determinism. Experimental data were obtained from the Madison Symmetric Torus RFP and consist of a wide array of both global and local diagnostic signals. None of the signals shows any indication of low-dimensional chaos or other simple determinism. Moreover, most of the analysis tools indicate that the experimental system is very high dimensional with properties similar to noise. Nonlinear noise reduction is unsuccessful at extracting an underlying deterministic system
SciDAC-Center for Plasma Edge Simulation
Energy Technology Data Exchange (ETDEWEB)
Chang, Choong Seock
2012-06-04
The SciDAC ProtoFSP Center for Plasma Edge Simulation (CPES) [http://www.cims.nyu.edu/cpes/] was awarded to New York University, Courant Institute of Mathematical Sciences in FY 2006. C.S. Chang was the institutional and national project PI. It's mission was 1) to build kinetic simulation code applicable to tokamak edge region including magnetic divertor geometry, 2) to build a computer science framework which can integrate the kinetic code with MHD/fluid codes in multiscale, 3) to conduct scientific research using the developed tools. CPES has built two such edge kinetic codes XGC0 and XGC1, which are still the only working kinetic edge plasma codes capable of including the diverted magnetic field geometry. CPES has also built the code coupling framework EFFIS (End-to-end Framework for Fusion Integrated Simulation), which incubated and used the Adios (www.olcf.ornl.gov/center-projects/adios/) and eSiMon (http://www.olcf.ornl.gov/center-projects/esimmon/) technologies, together with the Kepler technology.
Energy Technology Data Exchange (ETDEWEB)
Horioka, Kazuhiko (ed.)
2002-06-01
The papers presented at the symposium on ''Physics and application of high energy density plasmas, held December 20-21, 2001 at NIFS'' are collected in this proceedings. The topics covered in the meeting include dense z-pinches, plasma focus, intense charged particle beams, intense radiation sources, discharge pumped X-ray lasers, their diagnostics, and applications of them. The papers reflect the present status and trends in the research field of high energy density plasmas. (author)
Value for money in particle-mesh plasma simulations
International Nuclear Information System (INIS)
Eastwood, J.W.
1976-01-01
The established particle-mesh method of simulating a collisionless plasma is discussed. Problems are outlined, and it is stated that given constraints on mesh size and particle number, the only way to adjust the compromise between dispersive forces, collision time and heating time is by altering the force calculating cycle. In 'value for money', schemes, matching of parts of the force calculation cycle is optimized. Interparticle forces are considered. Optimized combinations of elements of the force calculation cycle are compared. Following sections cover the dispersion relation, and comparisons with other schemes. (U.K.)
A multilevel iterative field solver for implicit, kinetic, plasma simulation
International Nuclear Information System (INIS)
Knoll, D.A.; Lapenta, G.; Brackbill, J.U.
1999-01-01
The equation for electrostatic potential which arises from the implicit moment method in plasma simulation is a nonsymmetric elliptic equation. The authors present results using a simple multigrid method as a preconditioner to General Minimum RESidual (GMRES) to iteratively solve this nonsymmetric elliptic equation in two dimensions. It is demonstrated that a simple multigrid method produces an effective preconditioner. It is also demonstrated that under some conditions the required number of linear iterations is independent of grid dimension. Results are presented for both uniform and nonuniform grid problems
End-to-end plasma bubble PIC simulations on GPUs
Germaschewski, Kai; Fox, William; Matteucci, Jackson; Bhattacharjee, Amitava
2017-10-01
Accelerator technologies play a crucial role in eventually achieving exascale computing capabilities. The current and upcoming leadership machines at ORNL (Titan and Summit) employ Nvidia GPUs, which provide vast computational power but also need specifically adapted computational kernels to fully exploit them. In this work, we will show end-to-end particle-in-cell simulations of the formation, evolution and coalescence of laser-generated plasma bubbles. This work showcases the GPU capabilities of the PSC particle-in-cell code, which has been adapted for this problem to support particle injection, a heating operator and a collision operator on GPUs.
Multiple scattering of electromagnetic waves by a collection of plasma drift turbulent vortices
International Nuclear Information System (INIS)
Resendes, D.
1995-01-01
An application of the self-consistent multiple-scattering theory of electro-magnetic waves to drift turbulent vortices is presented. Using the known single-vortex solution, the integral equation describing the scattering from a finite density of drift turbulent vortices is obtained. Rather than solving this equation and then averaging, the averaging operation is taken first to obtain statistical moment equations, from which the coherent and incoherent scattering follow. These results are expressed in a Fourier basis, and the cross-section is evaluated. Limiting forms of the theory and straightforward generalizations are discussed. (Author)
Energy Technology Data Exchange (ETDEWEB)
Wang, Zhaopin; Fei, Ying; Liu, Hui [Zhejiang Univ., Hangzhou (China). Dept. of Epidemiology and Health Statistics; Zhejiang Univ., Hangzhou (China). Chronic Disease Research Inst.; and others
2016-01-15
The potential health risks of electromagnetic fields (EMFs) have currently raised considerable public concerns. The aim of this study was to evaluate the effects of EMF exposure on levels of plasma hormonal and inflammatory pathway biomarkers in male workers of an electric power plant. Seventy-seven male workers with high occupational EMF exposure and 77 male controls with low exposure, matched by age, were selected from a cross-sectional study. Moreover, high EMF exposure group was with walkie-talkies usage and exposed to power frequency EMF at the work places for a longer duration than control group. A questionnaire was applied to obtain relevant information, including sociodemographic characteristics, lifestyle factors, and EMF exposures. Plasma levels of testosterone, estradiol, melatonin, NF-KB, heat-shock protein (HSP) 70, HSP27, and TET1 were determined by an enzyme-linked immunosorbent assay. EMF exposure group had statistically significantly lower levels of testosterone (β = -0.3 nmol/L, P = 0.015), testosterone/estradiol (T/E2) ratio (β = -15.6, P = 0.037), and NF-KB (β = -20.8 ng/L, P = 0.045) than control group. Moreover, joint effects between occupational EMF exposure and employment duration, mobile phone fees, years of mobile phone usage, and electric fees on levels of testosterone and T/E2 ratio were observed. Nevertheless, no statistically significant associations of EMF exposures with plasma estradiol, melatonin, HSP70, HSP27, and TET1 were found. The findings showed that chronic exposure to EMF could decrease male plasma testosterone and T/E2 ratio, and it might possibly affect reproductive functions in males. No significant associations of EMF exposure with inflammatory pathway biomarkers were found.
International Nuclear Information System (INIS)
Birdsall, C.K.
1986-01-01
Our group uses theory and simulation as tools in order to increase the understanding of plasma instabilities, heating, transport, plasma-wall interactions, and large potentials in plasmas. We also work on the improvement of simulation both theoretically and practically. Two separate papers are included in this report
Pellat, Rene; Le Contel, Olivier; Roux, Alain; Perraut, Sylvaine; Hurricane, Omar; Coroniti, Ferdinand V.
We describe a new self-consistent kinetic approach of collisionless plasmas. The basic equations are obtained from a linearization of the cyclotron and bounce averaged Vlasov and Maxwell equations. In the low frequency limit the Gauss equation is shown to be equivalent to the Quasi-Neutrality Condition (QNC). First we describe the work of Hurricane et al., 1995b, who investigated the effect of stochasticity on the stability of ballooning modes. An expression for the energy principle is obtained in the stochastic case, with comparisons with the adiabatic case. Notably, we show how the non adiabaticity of ions allows to recover a MHD-like theory with a modification of the polytropic index, for waves with frequencies smaller than the bounce frequency of protons. The stochasticity of protons can be due, in the far plasma sheet (beyond 10-12 RE, RE being the Earth radius), to the development of thin Current Sheet (CS) with a curvature radius that becomes smaller than the ion Larmor radius. Conversely the near Earth plasma sheet (6-8 RE), where the curvature radius is larger, is expected to be in the adiabatic regime. We give a description of slowly evolving (quasi-static) magnetic configurations, during the formation of high altitudes CS's, for instance during substorm growth phase in the Earth magnetosphere, and tentatively during the formation of CS's in the solar corona. Thanks to the use of a simple equilibrium magnetic field, a 2D dipole, the linear electromagnetic perturbations are computed analytically as functions of a forcing electrical current. The QNC, which is valid for long perpendicular wavelength electromagnetic perturbations (kλD1 where λD is the Debye length), is developed via an expansion in the small parameter Te/Ti. To the lowest order in Te/Ti (Te/Ti->0) we find that the enforcement of the QNC implies the presence of an electrostatic potential which is constant along the field line, but varies across it. The corresponding potential electric field
Simulation of an Electromagnetic Acoustic Transducer Array by Using Analytical Method and FDTD
Directory of Open Access Journals (Sweden)
Yuedong Xie
2016-01-01
Full Text Available Previously, we developed a method based on FEM and FDTD for the study of an Electromagnetic Acoustic Transducer Array (EMAT. This paper presents a new analytical solution to the eddy current problem for the meander coil used in an EMAT, which is adapted from the classic Deeds and Dodd solution originally intended for circular coils. The analytical solution resulting from this novel adaptation exploits the large radius extrapolation and shows several advantages over the finite element method (FEM, especially in the higher frequency regime. The calculated Lorentz force density from the analytical EM solver is then coupled to the ultrasonic simulations, which exploit the finite-difference time-domain (FDTD method to describe the propagation of ultrasound waves, in particular for Rayleigh waves. Radiation pattern obtained with Hilbert transform on time-domain waveforms is proposed to characterise the sensor in terms of its beam directivity and field distribution along the steering angle, which can produce performance parameters for an EMAT array, facilitating the optimum design of such sensors.
Conceptual design and performance simulations of super-compact electromagnetic calorimeter
Directory of Open Access Journals (Sweden)
Skoda Libor
2013-11-01
Full Text Available Measurements of particle production at forward rapidities in high energy p-p, p-A and A-A collisions provide access to physics processes at very low Bjorken x. These measurements will allow to study the gluon saturation scale and improve our knowledge of parton distribution in nuclei. Specific requirements must be fulfilled for a calorimeter to successfully operate in high-multiplicity forward region within often stringent space limits. Here we present a study of a conceptual design of super-compact electromagnetic calorimeter being developed at Czech Technical University in Prague. The design of the sampling calorimeter is based on a sandwich structure of thin tungsten and scintillator layers oriented in parallel to the beam. Used optical readout of individual scintillator pads guaranties the required high radiation hardness of the detector. We present simulation of the expected performance of the optical pad readout together with overall detector performance. It is aimed for the detector to allow measuring of high energy photons (1
Nagaoka, Tomoaki; Watanabe, Soichi
2012-01-01
Electromagnetic simulation with anatomically realistic computational human model using the finite-difference time domain (FDTD) method has recently been performed in a number of fields in biomedical engineering. To improve the method's calculation speed and realize large-scale computing with the computational human model, we adapt three-dimensional FDTD code to a multi-GPU cluster environment with Compute Unified Device Architecture and Message Passing Interface. Our multi-GPU cluster system consists of three nodes. The seven GPU boards (NVIDIA Tesla C2070) are mounted on each node. We examined the performance of the FDTD calculation on multi-GPU cluster environment. We confirmed that the FDTD calculation on the multi-GPU clusters is faster than that on a multi-GPU (a single workstation), and we also found that the GPU cluster system calculate faster than a vector supercomputer. In addition, our GPU cluster system allowed us to perform the large-scale FDTD calculation because were able to use GPU memory of over 100 GB.
Studies on electromagnetic and charged particles radiations from pinched plasma sources
Neog, Nirod Kumar
Nuclear fusion is a process in which under certain condition, two light nuclei combine together to form a new heavier nucleus with consequent release of energy. It is to be noted that two fusing nuclei must come closer and closer until they react to form a single nucleus. But it is very difficult to squeeze of two nuclei to form a heavy nucleus due to the electrostatic coulomb repulsion between them. So, in order to over come this mutual electrostatic repulsion, the nuclei must have enough kinetic energy. This can be achieved by giving thermal energy to the fusing nuclei. Different schemes (like pinch effect, inertial confinement, magnetic confinement, etc.) have come out to provide necessary thermal energy to the fusing nuclei. One of such remarkable scheme, pinch effect, was invented during the mid of last century to achieve nuclear fusion. When a large current is passed through a conducting gas medium, its setup an azimuthal magnetic field, which tends to pinch the gas at the axis, thus generating high temperature and high density conducting ionized gas (plasma). This phenomenon is called as pinch effect. The self-generated magnetic field of the pinching plasma gives necessary thermal energy for fuse of light nuclei. A theory of pinch effect was first put forward by Bennett and later improved by others. The attempts of getting pinch fusion plasma led to give birth of theta-pinch and Z-pinch devices. Though both the approaches have failed to achieve the desired goal due to various plasma instabilities and other factors, still these devices are used in laboratories to study pinch plasma and to understand the mechanisms of neutron production, ion and electron production, and X-ray emission. Various other devices like compressional Z-pinch, exploding wire Z-pinch, gas puff Z-pinch, vacuum spark, gas embedded Z-pinch, capillary discharge plasma and plasma focus based on the principle of Z-pinch have developed in different laboratories all around the world to over
LDRD Final Report: Adaptive Methods for Laser Plasma Simulation
International Nuclear Information System (INIS)
Dorr, M R; Garaizar, F X; Hittinger, J A
2003-01-01
The goal of this project was to investigate the utility of parallel adaptive mesh refinement (AMR) in the simulation of laser plasma interaction (LPI). The scope of work included the development of new numerical methods and parallel implementation strategies. The primary deliverables were (1) parallel adaptive algorithms to solve a system of equations combining plasma fluid and light propagation models, (2) a research code implementing these algorithms, and (3) an analysis of the performance of parallel AMR on LPI problems. The project accomplished these objectives. New algorithms were developed for the solution of a system of equations describing LPI. These algorithms were implemented in a new research code named ALPS (Adaptive Laser Plasma Simulator) that was used to test the effectiveness of the AMR algorithms on the Laboratory's large-scale computer platforms. The details of the algorithm and the results of the numerical tests were documented in an article published in the Journal of Computational Physics [2]. A principal conclusion of this investigation is that AMR is most effective for LPI systems that are ''hydrodynamically large'', i.e., problems requiring the simulation of a large plasma volume relative to the volume occupied by the laser light. Since the plasma-only regions require less resolution than the laser light, AMR enables the use of efficient meshes for such problems. In contrast, AMR is less effective for, say, a single highly filamented beam propagating through a phase plate, since the resulting speckle pattern may be too dense to adequately separate scales with a locally refined mesh. Ultimately, the gain to be expected from the use of AMR is highly problem-dependent. One class of problems investigated in this project involved a pair of laser beams crossing in a plasma flow. Under certain conditions, energy can be transferred from one beam to the other via a resonant interaction with an ion acoustic wave in the crossing region. AMR provides an
Numerical simulation of nonequilibrium effects in an argon plasma jet
International Nuclear Information System (INIS)
Chang, C.H.; Ramshaw, J.D.
1994-01-01
Departures from thermal (translational), ionization, and excitation equilibrium in an axisymmetric argon plasma jet have been studied by two-dimensional numerical simulations. Electrons, ions, and excited and ground states of neutral atoms are represented as separate chemical species in the mixture. Transitions between excited states, as well as ionization/recombination reactions due to both collisional and radiative processes, are treated as separate chemical reactions. Resonance radiation transport is represented using Holstein escape factors to simulate both the optically thin and optically thick limits. The optically thin calculation showed significant underpopulation of excited species in the upstream part of the jet core, whereas in the optically thick calculation this region remains close to local thermodynamic equilibrium, consistent with previous experimental observations. Resonance radiation absorption is therefore an important effect. The optically thick calculation results also show overpopulations (relative to equilibrium) of excited species and electron densities in the fringes and downstream part of the jet core. In these regions, however, the electrons and ions are essentially in partial local thermodynamic equilibrium with the excited state at the electron temperature, even though the ionized and excited states are no longer in equilibrium with the ground state. Departures from partial local thermodynamic equilibrium are observed in the outer fringes and far downstream part of the jet. These results are interpreted in terms of the local relative time scales for the various physical and chemical processes occurring in the plasma
Moon, Hongsik
What is the impact of multicore and associated advanced technologies on computational software for science? Most researchers and students have multicore laptops or desktops for their research and they need computing power to run computational software packages. Computing power was initially derived from Central Processing Unit (CPU) clock speed. That changed when increases in clock speed became constrained by power requirements. Chip manufacturers turned to multicore CPU architectures and associated technological advancements to create the CPUs for the future. Most software applications benefited by the increased computing power the same way that increases in clock speed helped applications run faster. However, for Computational ElectroMagnetics (CEM) software developers, this change was not an obvious benefit - it appeared to be a detriment. Developers were challenged to find a way to correctly utilize the advancements in hardware so that their codes could benefit. The solution was parallelization and this dissertation details the investigation to address these challenges. Prior to multicore CPUs, advanced computer technologies were compared with the performance using benchmark software and the metric was FLoting-point Operations Per Seconds (FLOPS) which indicates system performance for scientific applications that make heavy use of floating-point calculations. Is FLOPS an effective metric for parallelized CEM simulation tools on new multicore system? Parallel CEM software needs to be benchmarked not only by FLOPS but also by the performance of other parameters related to type and utilization of the hardware, such as CPU, Random Access Memory (RAM), hard disk, network, etc. The codes need to be optimized for more than just FLOPs and new parameters must be included in benchmarking. In this dissertation, the parallel CEM software named High Order Basis Based Integral Equation Solver (HOBBIES) is introduced. This code was developed to address the needs of the
International Nuclear Information System (INIS)
Vay, J.-L.; Colella, P.; McCorquodale, P.; Van Straalen, B.; Friedman, A.; Grote, D.P.
2002-01-01
The numerical simulation of the driving beams in a heavy ion fusion power plant is a challenging task, and simulation of the power plant as a whole, or even of the driver, is not yet possible. Despite the rapid progress in computer power, past and anticipated, one must consider the use of the most advanced numerical techniques, if we are to reach our goal expeditiously. One of the difficulties of these simulations resides in the disparity of scales, in time and in space, which must be resolved. When these disparities are in distinctive zones of the simulation region, a method which has proven to be effective in other areas (e.g., fluid dynamics simulations) is the mesh refinement technique. They discuss the challenges posed by the implementation of this technique into plasma simulations (due to the presence of particles and electromagnetic waves). They will present the prospects for and projected benefits of its application to heavy ion fusion. In particular to the simulation of the ion source and the final beam propagation in the chamber. A collaboration project is under way at LBNL between the Applied Numerical Algorithms Group (ANAG) and the HIF group to couple the Adaptive Mesh Refinement (AMR) library (CHOMBO) developed by the ANAG group to the Particle-In-Cell accelerator code WARP developed by the HIF-VNL. They describe their progress and present their initial findings
Energy Technology Data Exchange (ETDEWEB)
Vay, J.-L.; Colella, P.; McCorquodale, P.; Van Straalen, B.; Friedman, A.; Grote, D.P.
2002-05-01
The numerical simulation of the driving beams in a heavy ion fusion power plant is a challenging task, and simulation of the power plant as a whole, or even of the driver, is not yet possible. Despite the rapid progress in computer power, past and anticipated, one must consider the use of the most advanced numerical techniques, if we are to reach our goal expeditiously. One of the difficulties of these simulations resides in the disparity of scales, in time and in space, which must be resolved. When these disparities are in distinctive zones of the simulation region, a method which has proven to be effective in other areas (e.g., fluid dynamics simulations) is the mesh refinement technique. They discuss the challenges posed by the implementation of this technique into plasma simulations (due to the presence of particles and electromagnetic waves). They will present the prospects for and projected benefits of its application to heavy ion fusion. In particular to the simulation of the ion source and the final beam propagation in the chamber. A collaboration project is under way at LBNL between the Applied Numerical Algorithms Group (ANAG) and the HIF group to couple the Adaptive Mesh Refinement (AMR) library (CHOMBO) developed by the ANAG group to the Particle-In-Cell accelerator code WARP developed by the HIF-VNL. They describe their progress and present their initial findings.
Turbulent transport in magnetized plasmas
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.
Model for resonant plasma probe.
Energy Technology Data Exchange (ETDEWEB)
Warne, Larry Kevin; Johnson, William Arthur; Hebner, Gregory Albert; Jorgenson, Roy E.; Coats, Rebecca Sue
2007-04-01
This report constructs simple circuit models for a hairpin shaped resonant plasma probe. Effects of the plasma sheath region surrounding the wires making up the probe are determined. Electromagnetic simulations of the probe are compared to the circuit model results. The perturbing effects of the disc cavity in which the probe operates are also found.
Direct Simulation Monte Carlo Simulations of Low Pressure Semiconductor Plasma Processing
International Nuclear Information System (INIS)
Gochberg, L. A.; Ozawa, T.; Deng, H.; Levin, D. A.
2008-01-01
The two widely used plasma deposition tools for semiconductor processing are Ionized Metal Physical Vapor Deposition (IMPVD) of metals using either planar or hollow cathode magnetrons (HCM), and inductively-coupled plasma (ICP) deposition of dielectrics in High Density Plasma Chemical Vapor Deposition (HDP-CVD) reactors. In these systems, the injected neutral gas flows are generally in the transonic to supersonic flow regime. The Hybrid Plasma Equipment Model (HPEM) has been developed and is strategically and beneficially applied to the design of these tools and their processes. For the most part, the model uses continuum-based techniques, and thus, as pressures decrease below 10 mTorr, the continuum approaches in the model become questionable. Modifications have been previously made to the HPEM to significantly improve its accuracy in this pressure regime. In particular, the Ion Monte Carlo Simulation (IMCS) was added, wherein a Monte Carlo simulation is used to obtain ion and neutral velocity distributions in much the same way as in direct simulation Monte Carlo (DSMC). As a further refinement, this work presents the first steps towards the adaptation of full DSMC calculations to replace part of the flow module within the HPEM. Six species (Ar, Cu, Ar*, Cu*, Ar + , and Cu + ) are modeled in DSMC. To couple SMILE as a module to the HPEM, source functions for species, momentum and energy from plasma sources will be provided by the HPEM. The DSMC module will then compute a quasi-converged flow field that will provide neutral and ion species densities, momenta and temperatures. In this work, the HPEM results for a hollow cathode magnetron (HCM) IMPVD process using the Boltzmann distribution are compared with DSMC results using portions of those HPEM computations as an initial condition.
Dols, V. J.; Delamere, P. A.; Bagenal, F.; Cassidy, T. A.; Crary, F. J.
2014-12-01
We model the interaction of Europa's tenuous atmosphere with the plasma of Jupiter's torus with an improved version of our hybrid plasma code. In a hybrid plasma code, the ions are treated as kinetic Macro-particles moving under the Lorentz force and the electrons as a fluid leading to a generalized formulation of Ohm's law. In this version, the spatial simulation domain is decomposed in 2 directions and is non-uniform in the plasma convection direction. The code is run on a multi-processor supercomputer that offers 16416 cores and 2GB Ram per core. This new version allows us to tap into the large memory of the supercomputer and simulate the full interaction volume (Reuropa=1561km) with a high spatial resolution (50km). Compared to Io, Europa's atmosphere is about 100 times more tenuous, the ambient magnetic field is weaker and the density of incident plasma is lower. Consequently, the electrodynamic interaction is also weaker and substantial fluxes of thermal torus ions might reach and sputter the icy surface. Molecular O2 is the dominant atmospheric product of this surface sputtering. Observations of oxygen UV emissions (specifically the ratio of OI 1356A / 1304A emissions) are roughly consistent with an atmosphere that is composed predominantely of O2 with a small amount of atomic O. Galileo observations along flybys close to Europa have revealed the existence of induced currents in a conducting ocean under the icy crust. They also showed that, from flyby to flyby, the plasma interaction is very variable. Asymmetries of the plasma density and temperature in the wake of Europa were also observed and still elude a clear explanation. Galileo mag data also detected ion cyclotron waves, which is an indication of heavy ion pickup close to the moon. We prescribe an O2 atmosphere with a vertical density column consistent with UV observations and model the plasma properties along several Galileo flybys of the moon. We compare our results with the magnetometer
Energy Technology Data Exchange (ETDEWEB)
Whitlow, K.; Stepanyan, S.
2007-01-01
Hall B at the Thomas Jefferson National Accelerator Facility uses the CEBAF (Continuous Electron Beam Accelerator Facility) Large Acceptance Spectrometer (CLAS) to study the structure of the nucleon. An upgrade from a 6 GeV beam to a 12GeV beam is currently planned. With the beam energy upgrade, more high-energy pions will be created from the interaction of the beam and the target. Above 6GeV, the angle between the two-decay photons of high-energy pions becomes too small for the current electromagnetic calorimeter (EC) of CLAS to differentiate between two photon clusters and single photon events. Thus, a preshower calorimeter will be added in front of the EC to enable fi ner granularity and ensure better cluster separation for all CLAS experiments at higher energies. In order to optimize cost without compromising the calorimeter’s performance, three versions of the preshower, varying in number of scintillator and lead layers, were compared by their resolution and effi ciency. Using GSIM, a GEANT detector simulation program for CLAS, the passage of neutral pions and single photons through CLAS and the new preshower calorimeter (CLAS12 EC) was studied. The resolution of the CLAS12 EC was calculated from the Gaussian fi t of the sampling fraction, the energy CLAS12 EC detected over the Monte Carlo simulated energy. The single photon detection effi ciency was determined from the energy and position of the photon hits. The fractional energy resolution measured was ΔE/E = 0.0972 in the fi ve-module version, 0.111 in the four-module version, and 0.149 in the three-module version. Both the fi ve- and four-module versions had 99% single photon detection effi ciency above 0.5GeV while the 3 module version had 99% effi ciency above 1.5GeV. Based on these results, the suggested preshower confi guration is the four-module version containing twelve layers of scintillator and fi fteen layers of lead. This version provides a reasonable balance of resolution, effi ciency, and
Fully Kinetic Ion Models for Magnetized Plasma Simulations
Sturdevant, Benjamin J.
This thesis focuses on the development of simulation models, based on fully resolving the gyro-motion of ions with the Lorentz force equations of motion, for studying low-frequency phenomena in well-magnetized plasma systems. Such models, known as fully kinetic ion models, offer formal simplicity over higher order gyrokinetic ion models and may provide an important validation tool or replacement for gyrokinetic ion models in applications where the gyrokinetic ordering assumptions are in question. Methods for dealing with the added difficulty of resolving the short time scales associated with the ion gyro-motion in fully kinetic ion models are explored with the use of graphics processing units (GPUs) and advanced time integration algorithms, including sub-cycling, orbit averaging and variational integrators. Theoretical work is performed to analyze the effects of the ion Bernstein modes, which are known to cause difficulties in simulations based on fully kinetic ion models. In addition, the first simulation results for the ion temperature gradient driven instability in toroidal geometry using a fully kinetic ion model are presented. Finally, during the course of this work, a method for analyzing the effects of a finite time step size and spatial grid in the delta-f approach to the particle-in-cell method was developed for the first time. This method was applied to an implicit time integration scheme and has revealed some unusual numerical properties related to the delta-f method.
DEFF Research Database (Denmark)
Xu, G.S.; Naulin, Volker; Fundamenski, W.
2010-01-01
energy, magnetic momentum, and angular momentum. The perpendicular vortex motions and the kinetic shear Alfvén waves are coupled through the parallel current and Ampere’s law, leading to field line bending. On the timescale of interchange motion τ⊥, a thermal expansion force in the direction of curvature...... filaments in a nonuniformly and strongly magnetized plasma are revisited. We systemize the Lagrangian-invariant-based method. Six Lagrangian invariants are employed to describe structure motion and the resultant convective transport, namely, magnetic flux, background magnetic energy, specific entropy, total...... gradient is converted into the kinetic energy of convective motion and the magnetic energy of field line bending through reversible pressure-volume work as a result of the plasma compressibility in an inhomogeneous magnetic field. On the timescale of parallel acoustic response τ∥⪢τ⊥, part of the filament...
Propagation of a surface electromagnetic wave in a plasma with allowance for electron heating
International Nuclear Information System (INIS)
Boev, A.G.; Prokopov, A.V.
1978-01-01
Considered is propagation of a surface high-frequency wave in a semibounded plasma, which electron component is heated within the wave field. Dissipative effects are considered small, that is possible if wave frequency is much higher than the collision frequency and phase velocity of wave considerably exceeds electron heat velocity. Under conditions of anomalous skin-effect the distributions of electron temperature and wave damping have been found. It is established, that higher electron temperature on the boundary results in a higher decrease of temperature inside a plasma, far from the boundary temperature decreases exponentially; damping coefficient under anomalous skin-effect conditions is characterized by a stronger dependence not only on the wave amplitude, but as well as on gas pressure and wave frequency in comparison with normal conditions
Electromagnetic instability of a beam of charged particles in a dense plasma
International Nuclear Information System (INIS)
Gordeev, A.V.; Rudakov, L.I.
1982-01-01
We investigate magnetic-field generation due to filamentation of a beam of charged particles propagating in a dense plasma under conditions of strong current neutralization. The filamentation mechanism is determined by inductive or dissipative magnetic-field accumulation which leads to an inertialess restructuring of the equilibrium of the charged-particle beam. The characteristic generation times of a magnetic field that leads to a substantial increase of the angular spread of the particles are indicated for typical beam and laser experiments
International Nuclear Information System (INIS)
Khalil, Sh.M.; El-Sherif, N.; El-Siragy, N.M.; Tanta Univ.; El-Naggar, I.A.; Alexandria Univ.
1985-01-01
Investigation is made for nonlinear interaction between incident radiation and a surface wave in a magnetized plasma layer. Both interacting waves are of P polarization. The generated currents and fields at combination frequencies are obtained analytically. Unlike the S-polarized interacting waves, the magnetic field affects the fundamental waves and leads to an amplification of generated waves when their frequencies approach the cyclotron frequency. (author)
Mattei, Stefano; Lettry, Jacques
2017-07-25
Linac4 is the new negative hydrogen ion (H$^-$) linear accelerator of the European Organization for Nuclear Research (CERN). Its ion source operates on the principle of Radio-Frequency Inductively Coupled Plasma (RF-ICP) and it is required to provide 50~mA of H$^-$ beam in pulses of 600~$\\mu$s with a repetition rate up to 2 Hz and within an RMS emittance of 0.25~$\\pi$~mm~mrad in order to fullfil the requirements of the accelerator. This thesis is dedicated to the characterization of the hydrogen plasma in the Linac4 H$^-$ ion source. We have developed a Particle-In-Cell Monte Carlo Collision (PIC-MCC) code to simulate the RF-ICP heating mechanism and performed measurements to benchmark the fraction of the simulation outputs that can be experimentally accessed. The code solves self-consistently the interaction between the electromagnetic field generated by the RF coil and the resulting plasma response, including a kinetic description of charged and neutral species. A fully-implicit implementation allowed to si...
Electron Beam Propagation in a Plasma
Directory of Open Access Journals (Sweden)
Kyoung W. Min
1988-06-01
Full Text Available Electron beam propagation in a fully ionized plasma has been studied using a one-dimensional particle simulation model. We compare the results of electrostatic simulations to those of electromagnetic simulations. The electrostatic results show the essential features of beam-plasma instability which accelerates ambient plasmas. The results also show the heating of ambient plasmas and the trapping of plasmas due to the locally generated electric field. The level of the radiation generated by the same non-relativistic beam is slightly higher than the noise level. We discuss the results in context of the heating of coronal plasma during solar flares.
International Nuclear Information System (INIS)
Haruki, T.; Yousefi, H. R.; Sakai, J.-I.
2010-01-01
Two dimensional particle-in-cell simulations of a dense plasma focus were performed to investigate a plasma heating process caused by the coalescence of multiple current loops in a proton-boron-electron plasma. Recently, it was reported that the electric field produced during the coalescence of two current loops in a proton-boron-electron plasma heats up all plasma species; proton-boron nuclear fusion may therefore be achievable using a dense plasma focus device. Based on this work, the coalescence process for four and eight current loops was investigated. It was found that the return current plays an important role in both the current pinch and the plasma heating. The coalescence of four current loops led to the breakup of the return current from the pinched plasma, resulting in plasma heating. For the coalescence of eight current loops, the plasma was confined by the pinch but the plasma heating was smaller than the two and four loop cases. Therefore the heating associated with current loop coalescence depends on the number of initial current loops. These results are useful for understanding the coalescence of multiple current loops in a proton-boron-electron plasma.
Atomic physics for simulations and diagnostics of plasmas
Klapisch, Marcel
2000-10-01
Recent progress in target design for laser induced ICF[1]has shown the importance of reliable atomic physics for simulating radiation of heavy elements. As for diagnostic purposes, one can usually choose elements to generate simple spectra from which temperature and densities can be deduced. I will describe atomic physics methods addressing both needs of plasma physics. Low density (e.g. Tokamaks) and high density (e.g. laser-produced) plasmas can be described in a unified manner within the collisional radiative model (CRM), bridging between the corona equilibrium and local thermodynamic equilibrium (LTE). The domain of validity of theses two limits will be discussed. The importance of self-generated or external radiation fields raises the dilemma of including atomic models on-line with the hydrodynamics (atomic description approximated) or off-line (radiation approximated). For simple spectra (low Z elements, H and He-like heavier ions) available methods and databases for rates of the various processes involved will be described. However, for complex spectra (medium to high Z atoms not fully ionized), detailed application of the CRM is usually not possible due to the number of energy levels and/or processes. The approach of ``unresolved transition arrays" (UTA)[2] and ``super transition arrays" (STA)[3], for LTE and non-LTE [4] will be presented in some details. [1]D. G. Colombant, S. E. Bodner, A. J. Schmitt, et al., Phys. Plasmas 7, 2046 (2000); 7, 2298 (2000). [2]J. Bauche, C. Bauche-Arnoult and M. Klapisch, Advance At. Mol. Phys. 23, 131(1987). [3]A. Bar-Shalom, J. Oreg, W. H. Goldstein, et al., Phys. Rev. A 40, 3183 (1989). [4]A. Bar-Shalom, J. Oreg and M. Klapisch, J. Quant. Spectrosc. Radiat. Transfer 58, 427 (1997).
Lathrop, Daniel; Eiskowitz, Skylar; Rojas, Ruben
2017-11-01
In clouds of suspended particles, collisions electrify particles and the clouds produce electric potential differences over large scales. This is seen in the atmosphere as lightning in thunderstorms, thundersnow, dust storms, and volcanic ash plumes, but it is a general phenomena in granular systems. The electrification process is not well understood. To investigate the relative importance of particle material properties and collective phenomena in granular and atmospheric electrification, we used several tabletop experiments that excite particle-laden flows. Various electromagnetic phenomena ensue. Measured electric fields result from capacitive and direct charge transfer to electrodes. These results suggest that while particle properties do matter (as previous investigations have shown), macroscopic electrification of granular flows is somewhat material independent and large-scale collective phenomena play a major role. As well, our results on charge separation and Hall effects suggest a very different view of the dynamics of clouds, planetary rings, and cold accretion disks in proto-planetary systems. We gratefully acknowledge past funding from the Julian Schwinger Foundation as well as the Ph.D. work of Freja Nordsiek.
Parallel pic plasma simulation through particle decomposition techniques
International Nuclear Information System (INIS)
Briguglio, S.; Vlad, G.; Di Martino, B.; Naples, Univ. 'Federico II'
1998-02-01
Particle-in-cell (PIC) codes are among the major candidates to yield a satisfactory description of the detail of kinetic effects, such as the resonant wave-particle interaction, relevant in determining the transport mechanism in magnetically confined plasmas. A significant improvement of the simulation performance of such codes con be expected from parallelization, e.g., by distributing the particle population among several parallel processors. Parallelization of a hybrid magnetohydrodynamic-gyrokinetic code has been accomplished within the High Performance Fortran (HPF) framework, and tested on the IBM SP2 parallel system, using a 'particle decomposition' technique. The adopted technique requires a moderate effort in porting the code in parallel form and results in intrinsic load balancing and modest inter processor communication. The performance tests obtained confirm the hypothesis of high effectiveness of the strategy, if targeted towards moderately parallel architectures. Optimal use of resources is also discussed with reference to a specific physics problem [it
Plasma simulation of electron avalanche in a linear thyratron
International Nuclear Information System (INIS)
Kushner, M.J.
1985-01-01
Thyratrons typically operate at sufficiently small PD (pressure x electrode separation) that holdoff is obtained by operating on the near side of the Paschen curve, and by shielding the slot in the control grid so there is no straight line path for electrons to reach the anode from the cathode. Electron avalanche is initiated by pulsing the control grid to a high voltage. Upon collapse of voltage in the cathode-control grid space, the discharge is sustained by penetration of potential through the control grid slot into the cathode-control grid region. To better understand the electron avalanche process in multi-grid and slotted structures such as thyratrons, a plasma simulation code has been constructed. This effort is in support of a companion program in which a linear thyratron is being electrically and spectroscopically characterized
Simulations of Neon Pellets for Plasma Disruption Mitigation in Tokamaks
Bosviel, Nicolas; Samulyak, Roman; Parks, Paul
2017-10-01
Numerical studies of the ablation of neon pellets in tokamaks in the plasma disruption mitigation parameter space have been performed using a time-dependent pellet ablation model based on the front tracking code FronTier-MHD. The main features of the model include the explicit tracking of the solid pellet/ablated gas interface, a self-consistent evolving potential distribution in the ablation cloud, JxB forces, atomic processes, and an improved electrical conductivity model. The equation of state model accounts for atomic processes in the ablation cloud as well as deviations from the ideal gas law in the dense, cold layers of neon gas near the pellet surface. Simulations predict processes in the ablation cloud and pellet ablation rates and address the sensitivity of pellet ablation processes to details of physics models, in particular the equation of state.
Mixed-Language High-Performance Computing for Plasma Simulations
Directory of Open Access Journals (Sweden)
Quanming Lu
2003-01-01
Full Text Available Java is receiving increasing attention as the most popular platform for distributed computing. However, programmers are still reluctant to embrace Java as a tool for writing scientific and engineering applications due to its still noticeable performance drawbacks compared with other programming languages such as Fortran or C. In this paper, we present a hybrid Java/Fortran implementation of a parallel particle-in-cell (PIC algorithm for plasma simulations. In our approach, the time-consuming components of this application are designed and implemented as Fortran subroutines, while less calculation-intensive components usually involved in building the user interface are written in Java. The two types of software modules have been glued together using the Java native interface (JNI. Our mixed-language PIC code was tested and its performance compared with pure Java and Fortran versions of the same algorithm on a Sun E6500 SMP system and a Linux cluster of Pentium~III machines.
Efficient Implicit Plasma Simulation Using Quadrature Moment Inverson
Larson, David
2017-10-01
Quadrature moment inversion algorithms are one route to reducing the computational effort required for fully implicit PIC plasma simulation. These algorithms compute a sparse quadrature representation of the velocity distribution from a set of velocity moments. A Jacobian-free Newton Krylov (JFNK) solver can then be used to concurrently solve Maxwell's equations and the quadrature node equations of motion implicitly differenced in time using the midpoint rule, retaining the fully kinetic character of the overall system. The results of several test problems will be presented along with an exploration of routes to achieving convergence of the complete set of PIC particles and field equations. This work was performed under the auspices of the U.S. DOE by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
LANGMUIR WAVE DECAY IN INHOMOGENEOUS SOLAR WIND PLASMAS: SIMULATION RESULTS
Energy Technology Data Exchange (ETDEWEB)
Krafft, C. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, F-91128 Palaiseau Cedex (France); Volokitin, A. S. [IZMIRAN, Troitsk, 142190, Moscow (Russian Federation); Krasnoselskikh, V. V., E-mail: catherine.krafft@u-psud.fr [Laboratoire de Physique et Chimie de l’Environnement et de l’Espace, 3A Av. de la Recherche Scientifique, F-45071 Orléans Cedex 2 (France)
2015-08-20
Langmuir turbulence excited by electron flows in solar wind plasmas is studied on the basis of numerical simulations. In particular, nonlinear wave decay processes involving ion-sound (IS) waves are considered in order to understand their dependence on external long-wavelength plasma density fluctuations. In the presence of inhomogeneities, it is shown that the decay processes are localized in space and, due to the differences between the group velocities of Langmuir and IS waves, their duration is limited so that a full nonlinear saturation cannot be achieved. The reflection and the scattering of Langmuir wave packets on the ambient and randomly varying density fluctuations lead to crucial effects impacting the development of the IS wave spectrum. Notably, beatings between forward propagating Langmuir waves and reflected ones result in the parametric generation of waves of noticeable amplitudes and in the amplification of IS waves. These processes, repeated at different space locations, form a series of cascades of wave energy transfer, similar to those studied in the frame of weak turbulence theory. The dynamics of such a cascading mechanism and its influence on the acceleration of the most energetic part of the electron beam are studied. Finally, the role of the decay processes in the shaping of the profiles of the Langmuir wave packets is discussed, and the waveforms calculated are compared with those observed recently on board the spacecraft Solar TErrestrial RElations Observatory and WIND.
Simulation study of stepwise relaxation in a spheromak plasma
International Nuclear Information System (INIS)
Horiuchi, Ritoku; Uchida, Masaya; Sato, Tetsuya.
1991-10-01
The energy relaxation process of a spheromak plasma in a flux conserver is investigated by means of a three-dimensional magnetohydrodynamic simulation. The resistive decay of an initial force-free profile brings the spheromak plasma to an m = 1/n = 2 ideal kink unstable region. It is found that the energy relaxation takes place in two steps; namely, the relaxation consists of two physically distinguished phases, and there exists an intermediate phase in between, during which the relaxation becomes inactive temporarily. The first relaxation corresponds to the transition from an axially symmetric force-free state to a helically symmetric one with an n = 2 crescent magnetic island structure via the helical kink instability. The n = 2 helical structure is nonlinearly sustained in the intermediate phase. The helical twisting of the flux tube creates a reconnection current in the vicinity of the geometrical axis. The second relaxation is triggered by the rapid growth of the n = 1 mode when the reconnection current exceeds a critical value. The helical twisting relaxes through magnetic reconnection toward an axially symmetric force-free state. It is also found that the poloidal flux reduces during the helical twisting in the first relaxation and the generation of the toroidal flux occurs through the magnetic reconnection process in the second relaxation. (author)
Fully electromagnetic gyrokinetic eigenmode analysis of high-beta shaped plasmas
International Nuclear Information System (INIS)
Belli, E. A.; Candy, J.
2010-01-01
A new, more efficient method to compute unstable linear gyrokinetic eigenvalues and eigenvectors has been developed for drift-wave analysis of plasmas with arbitrary flux-surface shape, including both transverse and compressional magnetic perturbations. In high-beta, strongly shaped plasmas like in the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)], numerous branches of closely spaced unstable eigenmodes exist. These modes are difficult and time-consuming to adequately resolve with the existing linear initial-value solvers, which are further limited to the most unstable eigenmode. The new method is based on an eigenvalue approach and is an extension of the GYRO code [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)], reusing the existing discretization schemes in both real and velocity-space. Unlike recent methods, which use an iterative solver to compute eigenvalues of the relatively large gyrokinetic response matrix, the present scheme computes the zeros of the much smaller Maxwell dispersion matrix using a direct method. In the present work, the new eigensolver is applied to gyrokinetic stability analysis of a high-beta, NSTX-like plasma. We illustrate the smooth transformation from ion-temperature-gradient (ITG)-like to kinetic-ballooning (KBM)-like modes, and the formation of hybrid ITG/KBM modes, and further demonstrate the existence of high-k Alfvenic drift-wave 'cascades' for which the most unstable mode is a higher excited state along the field line. A new compressional electron drift wave, which is driven by a combination of strong beta and pressure gradient, is also identified for the first time. Overall, we find that accurate calculation of stability boundaries and growth rates cannot, in general, ignore the compressional component δB || of the perturbation.
Numerical simulation of electro-magnetic and flow fields of TiAl melt under electric field
Directory of Open Access Journals (Sweden)
Zhang Yong
2010-08-01
Full Text Available This article aims at building an electromagnetic and fluid model, based on the Maxwell equations and Navier-Stokes equations, in TiAl melt under two electric fields. FEM (Finite Element Method and APDL (ANSYS Parametric Design Language were employed to perform the simulation, model setup, loading and problem solving. The melt in molds of same cross section area with different flakiness ratio (i.e. width/depth under the load of sinusoidal current or pulse current was analyzed to obtain the distribution of electromagnetic field and flow field. The results show that the induced magnetic field occupies sufficiently the domain of the melt in the mold with a flakiness ratio of 5:1. The melt is driven bipolarly from the center in each electric field. It is also found that the pulse electric field actuates the TiAl melt to flow stronger than what the sinusoidal electric field does.
Jin, Kai; Vanka, Surya P.; Thomas, Brian G.
2018-02-01
In continuous casting of steel, argon gas is often injected to prevent clogging of the nozzle, but the bubbles affect the flow pattern, and may become entrapped to form defects in the final product. Further, an electromagnetic field is frequently applied to induce a braking effect on the flow field and modify the inclusion transport. In this study, a previously validated GPU-based in-house code CUFLOW is used to investigate the effect of electromagnetic braking on turbulent flow, bubble transport, and capture. Well-resolved large eddy simulations are combined with two-way coupled Lagrangian computations of the bubbles. The drag coefficient on the bubbles is modified to account for the effects of the magnetic field. The distribution of the argon bubbles, capture, and escape rates, are presented and compared with and without the magnetic field. The bubble capture patterns are also compared with results of a previous RANS model as well as with plant measurements.
International Nuclear Information System (INIS)
Iwashita, H.; Iwasa, H.; Hiraga, F.; Kamiyama, T.; Kiyanagi, Y.; Suzuki, J.; Shinohara, T.; Oku, T.; Shimizu, H.M.
2009-01-01
A pulsed sextupole electromagnetic lens with suitably controlled time-dependent magnetic field can in principle focus pulsed neutrons at the same focal point over a wide range of wavelength as the lens removes aberrations. However, in fact, it is difficult to focus neutrons over a wide range of wavelength because attenuation of a practical pulsed sextupole electromagnet is faster than an ideal case. We have devised a method of canceling the difference between the practical pulsed sextupole magnetic field and the ideal magnetic field with the use of a permanent sextupole magnet. We performed simulation calculations to investigate the feasibility of this method, and it was shown that focusing wavelength range spread compared with the case using a pulsed magnetic lens only. This result indicates the usefulness of the method.
Directory of Open Access Journals (Sweden)
Adam B. Sefkow
2008-07-01
Full Text Available Large-space-scale and long-time-scale plasma flow simulations are executed in order to study the spatial and temporal evolution of plasma parameters for two types of plasma sources used in the neutralized drift compression experiment (NDCX. The results help assess the charge neutralization conditions for ion beam compression experiments and can be employed in more sophisticated simulations, which previously neglected the dynamical evolution of the plasma. Three-dimensional simulations of a filtered cathodic-arc plasma source show the coupling efficiency of the plasma flow from the source to the drift region depends on geometrical factors. The nonuniform magnetic topology complicates the well-known general analytical considerations for evaluating guiding-center drifts, and particle-in-cell simulations provide a self-consistent evaluation of the physics in an otherwise challenging scenario. Plasma flow profiles of a ferroelectric plasma source demonstrate that the densities required for longitudinal compression experiments involving ion beams are provided over the drift length, and are in good agreement with measurements. Simulations involving azimuthally asymmetric plasma creation conditions show that symmetric profiles are nevertheless achieved at the time of peak on-axis plasma density. Also, the ferroelectric plasma expands upstream on the thermal expansion time scale, and therefore avoids the possibility of penetration into the acceleration gap and transport sections, where partial neutralization would increase the beam emittance. Future experiments on NDCX will investigate the transverse focusing of an axially compressing intense charge bunch to a sub-mm spot size with coincident focal planes using a strong final-focus solenoid. In order to fill a multi-tesla solenoid with the necessary high-density plasma for beam charge neutralization, the simulations predict that supersonically injected plasma from the low-field region will penetrate and
Barna, M.; Javurek, M.; Willers, B.; Eckert, S.; Reiter, J.
2016-07-01
At the voestalpine Stahl Donawitz GmbH the continuous casting of round steel blooms is commonly supported by electromagnetically induced stirring of the liquid steel flow. A number of beneficial effects are attributed to electromagnetic stirring in the mould region (M-EMS), e.g. the enhanced transition from columnar to equiaxed solidification, the homogenization of the liquid steel flow or the reduction of surface and subsurface defects. Although the positive effects of M-EMS can be seen on the blooms (e.g. in etchings), the link between electromagnetic stirring of the steel melt and the quality of the solidified bloom is not sufficiently understood. Theoretical considerations are often limited to general cases and their results are therefore not directly applicable to real continuous casting geometries. On the other hand, plant measurements can only be performed to a limited extent due to the harsh conditions and other restrictions (e.g. safety regulations). In this work an alternative approach is used to investigate the steel flow in a round bloom caster under the influence of M-EMS. In a 1:3 scale Perspex model of a round bloom strand, measurements of the flow under the influence of a rotating magnetic field can be conducted. These measurements provide a validation benchmark for the numeric simulations. A numeric model of the before mentioned 1:3 scale model is implemented, encompassing the strand, the submerged entry nozzle as well as the M-EMS device. In the modelling approach, the bidirectional coupling between liquid steel flow and the electromagnetic field/forces has to be considered because otherwise the resulting tangential velocities will be overestimated. With the validated modelling approach, simulations of real casting machines can then be conducted, stirring parameter influences can be shown and conclusions for the real casting process can be drawn.
High frequency electromagnetic modes in a weakly magnetized relativistic electron plasma
International Nuclear Information System (INIS)
Abbas, Gohar; Murtaza, G.; Kingham, R. J.
2010-01-01
Using the linearized Vlasov-Maxwell model, the polarization tensor for a weakly magnetized electron plasma is derived. For isotropic relativistic Maxwellian velocity distribution function, dispersion relations are obtained for both parallel and perpendicular propagations. The integrals (called Meijer G functions) that arise due to relativistic effects are examined in various limits and dispersion relations are derived for the nonrelativistic, weakly, strongly, and ultrarelativistic Maxwellian velocity distributions. It is generally observed that the propagation domains of the modes are enlarged as one proceeds from the nonrelativistic to the highly relativistic regime. Resultantly, due to the relativistic effects, the Whistler mode is suppressed in the R-wave, the nonpropagation band of X-mode is reduced, and the X-mode itself approaches the O-mode. Further, the results derived in the ultra- and nonrelativistic limits found to be in agreement with the earlier calculations [G. Abbas et al. Phys. Scr. 76, 649 (2007); F. F. Chen, Introduction to Plasma Physics and Controlled Fusion (Plenum, New York, 1984), Vol. 1].
Oh, Hyo-Jun; Dao, Van-Duong; Choi, Ho-Suk
2018-03-01
This study presents the first use of a plasma reduction reaction under atmospheric pressure to fabricate a thin silver layer on polyethylene terephthalate (PET) film without the use of toxic chemicals, high voltages, or an expensive vacuum apparatus. The developed film is applied to electromagnetic interference (EMI) shielding. After repeatedly depositing a silver layer through a plasma reduction reaction on PET, we can successfully fabricate a uniformly deposited thin silver layer. It was found that both the particle size and film thickness of thin silver layers fabricated at different AgNO3 concentrations increase with an increase in the concentration of AgNO3. However, the roughness of the thin silver layer decreases when increasing the concentration of AgNO3 from 100 to 500 mM, and the roughness increases with a further increase in the concentration of AgNO3. The EMI shielding effectiveness (SE) of the film is measured in the frequency range of 0.045 to 1 GHz. As a result of optimizing the electrical conductivity by measuring sheet resistance of the thin silver layer, the film fabricated from 500 mM AgNO3 exhibits the highest EMI SE among all fabricated films. The maximum values of the EMI SE are 60.490 dB at 0.1 GHz and 54.721 dB at 1.0 GHz with minimum sheet resistance of 0.244 Ω/□. Given that the proposed strategy is simple and effective, it is promising for fabricating various low-cost metal films with high EMI SE.
Processor-in-Loop Control System Design Using a Non-Real-Time Electro-Magnetic Transient Simulator
Chongva, Gregory
This thesis investigates using processor-in-loop techniques with non-real-time electro-magnetic tran- sient simulation software for designing microcontroller-based systems. The behaviour of a microcon- troller is included in the simulation by directly integrating the target microcontroller into an EMTP co-simulation. Additionally, to assist the design process, the optimization functionality of the EMTP program is extended to the microcontroller algorithm. Since non-realtime simulation does not require specialized test hardware to accurately simulate systems, it is both cheaper and able to be used earlier in the controller design process then hardware-in-loop real-time simulation. A component is created in the PSCAD / EMTDC program to integrate a generic controller running an arbitrary periodic algorithm into an EMTP simulation. The component operation is verified by creating a co-simulation of a three-phase induction motor V / f. speed control. The co-simulation results match the behaviour of the resulting system under a fairly broad range of operating conditions, highlighting the applicability of the technique.
International Nuclear Information System (INIS)
Swanson, D.G.; Wersinger, J.M.
1985-01-01
The program of theoretical studies of the heating of toroidal plasmas with radio frequency electromagnetic radiation has continued in three directions. A summary of principal accomplishments of the first nine months of this year's contract is presented. These include: (1) The development of a numerical program for complex ray tracing with focusing. (2) Several developments in mode conversion theory. and (3) several developments in Nonlinear Wave Energy Absorption
Blake, Douglas Clifton
A new methodology is presented for conducting numerical simulations of electromagnetic scattering and wave-propagation phenomena on massively parallel computing platforms. A process is constructed which is rooted in the Finite-Volume Time-Domain (FVTD) technique to create a simulation capability that is both versatile and practical. In terms of versatility, the method is platform independent, is easily modifiable, and is capable of solving a large number of problems with no alterations. In terms of practicality, the method is sophisticated enough to solve problems of engineering significance and is not limited to mere academic exercises. In order to achieve this capability, techniques are integrated from several scientific disciplines including computational fluid dynamics, computational electromagnetics, and parallel computing. The end result is the first FVTD solver capable of utilizing the highly flexible overset-gridding process in a distributed-memory computing environment. In the process of creating this capability, work is accomplished to conduct the first study designed to quantify the effects of domain-decomposition dimensionality on the parallel performance of hyperbolic partial differential equations solvers; to develop a new method of partitioning a computational domain comprised of overset grids; and to provide the first detailed assessment of the applicability of overset grids to the field of computational electromagnetics. Using these new methods and capabilities, results from a large number of wave propagation and scattering simulations are presented. The overset-grid FVTD algorithm is demonstrated to produce results of comparable accuracy to single-grid simulations while simultaneously shortening the grid-generation process and increasing the flexibility and utility of the FVTD technique. Furthermore, the new domain-decomposition approaches developed for overset grids are shown to be capable of producing partitions that are better load balanced and
Simulation study on the growth of grains in dusty plasmas
International Nuclear Information System (INIS)
Sato, Tetsuya; Watanabe, Kunihiko
1997-01-01
A new particle simulation code is developed for studying the dynamics of the grains which are exposed to charging by the background plasma particles. Effects of regular attachment of electrons and ions, effects of secondary electron emission, and coagulation of grains are included in this code. Simulation results show that grains randomly change their charges from negative to positive, or from positive to negative in a 'flip-flop' fashion as a result of competition between the electron attachment and secondary electron emission. It is found that the flip-flop effect becomes remarkable when the radius of grains is of the order of 10 nm, because the attachment of a single electron to a grain is less effective on the surface potential for larger grains, while the average probability of electron attachment is smaller for smaller grains. Grains with opposite charges attract each other to coagulate, so that grains of size of 10 nm are likely to grow in size. The flip-flop effect is found to be essential to the growth of grains. (author)
Electromagnetic wave matching device
International Nuclear Information System (INIS)
Hirata, Yosuke; Mitsunaka, Yoshika; Hayashi, Ken-ichi; Ito, Yasuyuki.
1997-01-01
The present invention provides an electromagnetic wave matching capable of reducing a cost for the transmission system in a system of using electromagnetic waves for plasma heating of a thermonuclear reactor. Namely, incident electromagnetic waves are reflected by using a plurality of phase correction mirrors. The reflected electromagnetic waves are connected to an external transmission system through an exit. The phase correction mirrors have such a shape to receive a plurality of beam-like electromagnetic waves and output electromagnetic waves by the number different from the number of the received electromagnetic wave beams having a predetermined distribution. Further, at least two of the phase correction mirrors have such a shape to change the phase of the electromagnetic waves beams incident to the reflection surface of the phase correction mirrors by a predetermined amount corresponding to the position of the reflection surface. Then, the cost for transmission system can greatly be reduced. (I.S.)
Progress in mesh-free plasma simulation with parallel tree codes
Czech Academy of Sciences Publication Activity Database
Gibbon, P.; Speck, R.; Karmakar, A.; Arnold, L.; Frings, W.; Berberich, B.; Reiter, D.; Mašek, Martin
2010-01-01
Roč. 38, č. 9 (2010), s. 2367-2376 ISSN 0093-3813 Institutional research plan: CEZ:AV0Z10100523 Keywords : plasma simulation * plasma transport properties * proton acceleration Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.070, year: 2010
Chemical equilibration in a viscous quark-gluon plasma and electromagnetic signals
Chaudhuri, A K
2000-01-01
We have investigated the chemical equilibration of the parton distributions in collisions of two heavy nuclei assuming the partonic fluid to be ideal as well as viscous. The initial conditions are taken from HIJING calculations for Au+Au collisions at RHIC and LHC energies. It is seen that when the viscous drag is taken into account, the lifetime of the plasma is increased by a factor of nearly two. The temperature as well as fugacities evolve more slowly than their ideal counterpart. Photon and lepton pair production are also investigated. With viscosity, there is a twofold increase in the photon and lepton pair production. The increase in the large p/sub T/ photons or large invariant mass lepton pairs is due to the slower rate of temperature evolution. (27 refs).
Time-stepped & discrete-event simulations of electromagnetic propulsion systems Project
National Aeronautics and Space Administration — The existing plasma codes are ill suited for modeling of mixed resolution problems, such as the plasma sail, where the system under study comprises subsystems with...
Time-stepped & discrete-event simulations of electromagnetic propulsion systems, Phase II
National Aeronautics and Space Administration — The existing plasma codes are ill suited for modeling of mixed resolution problems, such as the plasma sail, where the system under study comprises subsystems with...
Finite-Difference Algorithm for Simulating 3D Electromagnetic Wavefields in Conductive Media
Aldridge, D. F.; Bartel, L. C.; Knox, H. A.
2013-12-01
Electromagnetic (EM) wavefields are routinely used in geophysical exploration for detection and characterization of subsurface geological formations of economic interest. Recorded EM signals depend strongly on the current conductivity of geologic media. Hence, they are particularly useful for inferring fluid content of saturated porous bodies. In order to enhance understanding of field-recorded data, we are developing a numerical algorithm for simulating three-dimensional (3D) EM wave propagation and diffusion in heterogeneous conductive materials. Maxwell's equations are combined with isotropic constitutive relations to obtain a set of six, coupled, first-order partial differential equations governing the electric and magnetic vectors. An advantage of this system is that it does not contain spatial derivatives of the three medium parameters electric permittivity, magnetic permeability, and current conductivity. Numerical solution methodology consists of explicit, time-domain finite-differencing on a 3D staggered rectangular grid. Temporal and spatial FD operators have order 2 and N, where N is user-selectable. We use an artificially-large electric permittivity to maximize the FD timestep, and thus reduce execution time. For the low frequencies typically used in geophysical exploration, accuracy is not unduly compromised. Grid boundary reflections are mitigated via convolutional perfectly matched layers (C-PMLs) imposed at the six grid flanks. A shared-memory-parallel code implementation via OpenMP directives enables rapid algorithm execution on a multi-thread computational platform. Good agreement is obtained in comparisons of numerically-generated data with reference solutions. EM wavefields are sourced via point current density and magnetic dipole vectors. Spatially-extended inductive sources (current carrying wire loops) are under development. We are particularly interested in accurate representation of high-conductivity sub-grid-scale features that are common
International Nuclear Information System (INIS)
Nissanke, Samaya; Georgieva, Alexandra; Kasliwal, Mansi
2013-01-01
Combined gravitational wave (GW) and electromagnetic (EM) observations of compact binary mergers should enable detailed studies of astrophysical processes in the strong-field gravity regime. This decade, ground-based GW interferometers promise to routinely detect compact binary mergers. Unfortunately, networks of GW interferometers have poor angular resolution on the sky and their EM signatures are predicted to be faint. Therefore, a challenging goal will be to unambiguously pinpoint the EM counterparts of GW mergers. We perform the first comprehensive end-to-end simulation that focuses on: (1) GW sky localization, distance measures, and volume errors with two compact binary populations and four different GW networks; (2) subsequent EM detectability by a slew of multiwavelength telescopes; and (3) final identification of the merger counterpart amidst a sea of possible astrophysical false positives. First, we find that double neutron star binary mergers can be detected out to a maximum distance of 400 Mpc (or 750 Mpc) by three (or five) detector GW networks, respectively. Neutron-star-black-hole binary mergers can be detected a factor of 1.5 further out; their median to maximum sky localizations are 50-170 deg 2 (or 6-65 deg 2 ) for a three (or five) detector GW network. Second, by optimizing depth, cadence, and sky area, we quantify relative fractions of optical counterparts that are detectable by a suite of different aperture-size telescopes across the globe. Third, we present five case studies to illustrate the diversity of scenarios in secure identification of the EM counterpart. We discuss the case of a typical binary, neither beamed nor nearby, and the challenges associated with identifying an EM counterpart at both low and high Galactic latitudes. For the first time, we demonstrate how construction of low-latency GW volumes in conjunction with local universe galaxy catalogs can help solve the problem of false positives. We conclude with strategies that would
International Nuclear Information System (INIS)
Lee, W.W.
2003-01-01
Particle simulation has played an important role for the recent investigations on turbulence in magnetically confined plasmas. In this paper, theoretical and numerical properties of a gyrokinetic plasma as well as its relationship with magnetohydrodynamics (MHD) are discussed with the ultimate aim of simulating microturbulence in transport time scale using massively parallel computers
Electrostatic plasma simulation by Particle-In-Cell method using ANACONDA package
Blandón, J. S.; Grisales, J. P.; Riascos, H.
2017-06-01
Electrostatic plasma is the most representative and basic case in plasma physics field. One of its main characteristics is its ideal behavior, since it is assumed be in thermal equilibrium state. Through this assumption, it is possible to study various complex phenomena such as plasma oscillations, waves, instabilities or damping. Likewise, computational simulation of this specific plasma is the first step to analyze physics mechanisms on plasmas, which are not at equilibrium state, and hence plasma is not ideal. Particle-In-Cell (PIC) method is widely used because of its precision for this kind of cases. This work, presents PIC method implementation to simulate electrostatic plasma by Python, using ANACONDA packages. The code has been corroborated comparing previous theoretical results for three specific phenomena in cold plasmas: oscillations, Two-Stream instability (TSI) and Landau Damping(LD). Finally, parameters and results are discussed.
Numerical simulation and optimal control in plasma physics
International Nuclear Information System (INIS)
Blum, J.
1989-01-01
The topics covered in this book are: A free boundary problem: the axisymmetric equilibrium of the plasma in a Tokamak; Static control of the plasma boundary by external currents; Existence and control of a solution to the equilibrium problem in a simple case; Study of equilibrium solution branches and application to the stability of horizontal displacements; Identification of the plasma boundary and plasma current density from magnetic measurements; Evolution of the equilibrium at the diffusion time scale; Evolution of the equilibrium of a high aspect-ratio circular plasma; Stability and control of the horizontal displacement of the plasma
Optical properties of cluster plasma
Energy Technology Data Exchange (ETDEWEB)
Kishimoto, Yasuaki; Tajima, Toshiki [Japan Atomic Energy Research Inst., Neyagawa, Osaka (Japan). Kansai Research Establishment; Downer, M.C.
1998-03-01
It is shown that unlike a gas plasma or an electron plasma in a metal, an ionized clustered material (`cluster plasma`) permits propagation below the plasma cut-off of electromagnetic (EM) waves whose phase velocity is close to but below the speed of light. This results from the excitation of a plasma oscillation mode (and/or polarization mode) through the cluster surface which does not exist in usual gaseous plasma. The existence of this new optical mode, cluster mode, is confirmed via numerical simulation. (author)
International Nuclear Information System (INIS)
Okada, A.; Aso, Y.; Hosoya, H.; Kiritani, M.
2003-01-01
A coaxial plasma gun was designed for the injection of W into Cu, by employment of the high speed of W ions attained by electro-magnetic acceleration. Under acceleration at 5 kV, W atoms could be injected into a Cu substrate at depths up to about 30 μm, whereas under acceleration at 4 kV no injection was observed. The injected W was observed to have nonuniform spatial distribution provably forming clusters or small groups of particles. Under acceleration at 5 kV, the first plasma to arrive at the substrate has a velocity of 10 km s -1 , which is much higher than that of initial plasma under acceleration at 4 kV. Immediately after the initial plasma, the relationship between the velocities of the respective plasmas reverses, so that average velocity at 5 kV is lower than that at 4 kV. Maximum plasma velocity plays a major role in the injection of W; i.e. the depth of W injection may depend on the velocity of initially generated plasma. The subsequent plasma forms a W layer on the surface of the substrate
Study on Characteristics of Constricted DC Plasma Using Particle-In-Cell Simulator
International Nuclear Information System (INIS)
Jo, Jong Gap; Park, Yeong Shin; Hwang, Yong Seok
2010-01-01
In dc glow discharge, when anode size is smaller than cathode, very small and bright plasma ball occurs in front of anode. This plasma is called constricted dc plasma and characterized by a high plasma density in positive glow, so called plasma ball, compared to the conventional dc plasma. For the reason, this plasma is utilized to ion or electron beam sources since the beam currents are enhanced by the dense anode glow. However, correlations between characteristics of the plasma (plasma density, electron temperature and space potential) and discharge conditions (anode size, discharge voltage, discharge current, pressure) have been a little investigated definitely clear in previous study because of the trouble of a diagnosis. The plasma ball which is the most essential part of the constricted plasma is too small to diagnose precisely without disturbing plasma. Therefore, we tried to analyze the constricted plasma through computer simulation with Particle-In-Cell (PIC) code. In this study, simulation result of constricted dc plasma as well as conventional dc glow discharge will be addressed and compared with each others
A comparison of experimentally-determined plasma oscillation frequencies with simulation.
Peterson, Bryan G.; Hart, Grant W.; Spencer, Ross L.
2002-11-01
The frequencies of the various plasma oscillation modes (diocotron and Trivelpiece-Gould modes) in a non-neutral electron plasma are dependent on both the plasma temperature and on the plasma density profile. There have been difficulties in calculating mode frequencies that match those determined experimentally. We have experimentally measured the frequencies of the diocotron and T-G modes as well as the plasma density profile and temperature for several plasma conditions. These frequencies are compared with those obtained from kinetic simulations to determine the conditions necessary for a consistent fit to all the measured frequencies.
Gyrokinetic approach to the propagation of electromagnetic waves in nonuniform bounded plasma slabs
International Nuclear Information System (INIS)
Sauter, O.; Vaclavik, J.
1994-05-01
A new code, SEMAL, has been developed which solves the linearized Vlasov-Maxwell wave equations to all orders in Larmor radii. Arbitrary density and temperature profiles as well as nonuniform magnetic fields are considered in slab geometry. The vacuum regions adjacent to the plasma slab are limited by perfect conducting walls and contain an antenna as an excitation source. The linear response is obtained by solving the system of one first-order and two second-order integro-differential equations using a non-polluting finite element discretization. The general equations in the Fourier space, derived in a new comprehensive way, and their inverse transform, using k y =0, are described as well as the convergence and non-polluting properties of the method. We present the results concerning the influence of alpha particles on ICRF heating schemes for ITER, where we show that small alphas concentration can alter the steady-state operation envisaged with ICRF fast wave current-drive. (author) 7 figs., 3 tabs., 28 refs