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Title: Hybrid simulations of the interaction of hot gyrokinetic particles with MHD waves

Abstract

A self-consistent study of the interaction of energetic ions with low-frequency MHD waves is performed using hybrid MHD-gyrokinetic particle simulations. In particular, the excitation of magnetospheric hydromagnetic waves by magnetic drift-bounce resonance with energetic ring current ions is investigated. In the model, energetic ions are treated as gyrokinetic particles using fully electromagnetic gyro-center equations, while the cold background plasma is treated as a fluid. The particles are coupled to the fluid equations through their current which appear in the bulk plasma momentum equation: where {rho}{sub b}, V{sub b} and p{sub b} are bulk plasma density, velocity and pressure, n{sub h} and j{sub h} axe hot ion density and current density. Other equations for the bulk plasma axe that of the MHD equations including E = - V{sub b} x B/c. It is assumed that n{sub h} {much_lt} n{sub b}. Spatial gyroaveraging in the gyro-center equations of motion as well as transformation to physical space axe performed by using four or eight point gyroangle distribution, in order to include the finite Larmor radius effects. In test runs, good conservation of the total energy was obtained and the finite Larmor radius effects were well reproduced for k{sub {perpendicular}}{rho}{sub h} {approximately} 1. Sincemore » magnetic drift-bounce resonant instability is driven by radial pressure gradients and requires resonance between azimuthal ion drift motion and bounce motion along magnetic field line, 3-D simulations are necessary for its investigation. The use of a multiple spatial scale expansion method enables to separate the equilibrium spatial scale lengths from those of the perturbations. In this case the zero-order ion pressure and magnetic field gradients become input parameters for the 2-D simulation. The 2-D numerical model with fixed background inhomogeneity was developed and it is used to study the drift-bounce resonant instability in 2-D box geometry.« less

Authors:
; ;  [1];  [2]
  1. Dartmouth College, Hanover, NH (United States)
  2. Rice Univ., Houston, TX (United States)
Publication Date:
OSTI Identifier:
489426
Report Number(s):
CONF-960354-
TRN: 97:011570
Resource Type:
Conference
Resource Relation:
Conference: International Sherwood fusion theory conference, Philadelphia, PA (United States), 18-20 Mar 1996; Other Information: PBD: 1996; Related Information: Is Part Of 1996 international Sherwood fusion theory conference; PB: 244 p.
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; 70 PLASMA PHYSICS AND FUSION; MHD EQUILIBRIUM; PLASMA SIMULATION; EARTH MAGNETOSPHERE; EQUATIONS OF MOTION; PLASMA DENSITY; PLASMA WAVES

Citation Formats

Belova, E V, Denton, R E, Hudson, M K, and Chan, A A. Hybrid simulations of the interaction of hot gyrokinetic particles with MHD waves. United States: N. p., 1996. Web.
Belova, E V, Denton, R E, Hudson, M K, & Chan, A A. Hybrid simulations of the interaction of hot gyrokinetic particles with MHD waves. United States.
Belova, E V, Denton, R E, Hudson, M K, and Chan, A A. 1996. "Hybrid simulations of the interaction of hot gyrokinetic particles with MHD waves". United States.
@article{osti_489426,
title = {Hybrid simulations of the interaction of hot gyrokinetic particles with MHD waves},
author = {Belova, E V and Denton, R E and Hudson, M K and Chan, A A},
abstractNote = {A self-consistent study of the interaction of energetic ions with low-frequency MHD waves is performed using hybrid MHD-gyrokinetic particle simulations. In particular, the excitation of magnetospheric hydromagnetic waves by magnetic drift-bounce resonance with energetic ring current ions is investigated. In the model, energetic ions are treated as gyrokinetic particles using fully electromagnetic gyro-center equations, while the cold background plasma is treated as a fluid. The particles are coupled to the fluid equations through their current which appear in the bulk plasma momentum equation: where {rho}{sub b}, V{sub b} and p{sub b} are bulk plasma density, velocity and pressure, n{sub h} and j{sub h} axe hot ion density and current density. Other equations for the bulk plasma axe that of the MHD equations including E = - V{sub b} x B/c. It is assumed that n{sub h} {much_lt} n{sub b}. Spatial gyroaveraging in the gyro-center equations of motion as well as transformation to physical space axe performed by using four or eight point gyroangle distribution, in order to include the finite Larmor radius effects. In test runs, good conservation of the total energy was obtained and the finite Larmor radius effects were well reproduced for k{sub {perpendicular}}{rho}{sub h} {approximately} 1. Since magnetic drift-bounce resonant instability is driven by radial pressure gradients and requires resonance between azimuthal ion drift motion and bounce motion along magnetic field line, 3-D simulations are necessary for its investigation. The use of a multiple spatial scale expansion method enables to separate the equilibrium spatial scale lengths from those of the perturbations. In this case the zero-order ion pressure and magnetic field gradients become input parameters for the 2-D simulation. The 2-D numerical model with fixed background inhomogeneity was developed and it is used to study the drift-bounce resonant instability in 2-D box geometry.},
doi = {},
url = {https://www.osti.gov/biblio/489426}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Dec 31 00:00:00 EST 1996},
month = {Tue Dec 31 00:00:00 EST 1996}
}

Conference:
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