Expansion and nonlinear relaxation of a strongly magnetized non-neutral electron plasma due to elastic collisions with background neutral gas

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.871847· OSTI ID:254914

Davidson, R C; Moore, D A ^[1]

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1. Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

The expansion and nonlinear relaxation of a non-neutral electron plasma due to elastic collisions with constant collision frequency {nu}{sub {ital en}} between the plasma electrons and a low-density background neutral gas are investigated theoretically. The model treats the electrons as a strongly magnetized fluid ({omega}{sup 2}{sub {ital pe}}/{omega}{sup 2}{sub {ital ce}}{much_gt}1) with isothermal temperature {ital T}=const immersed in a uniform magnetic field {ital B}{sub 0}{bold e{cflx char}}{sub {ital z}}. The model also assumes an axisymmetric plasma column ({partial_derivative}/{partial_derivative}{theta}=0) with negligible axial variation ({partial_derivative}/{partial_derivative}{ital z}=0). Introducing the scaled radial coordinate {rho}={ital r}/{ital r}{sub 0}({ital t}), and the density profile {ital shape} {ital function} {eta}({rho},{ital t})=[2{pi}{ital r}{sup 2}{sub 0}({ital t})/{ital N}]{ital n}({ital r},{ital t}), a diffusion equation is derived that describes the nonlinear evolution and relaxation of {eta}({rho},{ital t}) in response to electron collisions with the neutral gas. A very important consequence of the present analysis is that electron{endash}neutral collisions ({nu}{sub {ital en}}{ne}0) cause the electron density profile to relax to a (slowly expanding) quasiequilibrium state with {ital identical} profile shape {eta}{sub eq}({rho}) to that which would be produced by relaxation to {ital thermal} {ital equilibrium} by electron{endash}electron collisions in the absence of background neutral gas ({nu}{sub {ital en}}=0). {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: Princeton Plasma Physics Laboratory
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 254914
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 3; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COLLISIONAL PLASMA
ELASTIC SCATTERING
ELECTRON DENSITY
ELECTRON GAS
ELECTRON-ATOM COLLISIONS
ELECTRON-ELECTRON COLLISIONS
PLASMA EXPANSION
RELAXATION
THERMAL EQUILIBRIUM