Influence of Finite Ion Larmor Radius Effects on the Ion Resonance Instability in a Nonneutral Plasma Column,
MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS AND ASTRONOMY
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This paper investigates the influence of finite ion Larmor radius effects on the ion resonance instability in a nonneutral plasma column aligned parallel to a uniform axial magnetic field B sub 0 e sub z. The analysis is carried out within the framework of a hybrid Vlasov-fluid model in which the ions are described by the Vlasov equation and the electrons are described as a macroscopic, cold fluid. Electrostatic stability properties are calculated for the case in which the equilibrium electron and ion density profiles are rectangular and the ion distribution function is specified. The resulting eigenvalue equation for the perturbed electrostatic potential is solved exactly to give a closed algebraic dispersion relation. This dispersion relation is solved numerically, and it is shown that the growth rate of the ion resonance instability exhibits a sensitive dependence on plasma parameters. For example, finite ion Larmor radius effects can have a strong stabilizing influence for azimuthal mode numbers l or 2, particularly when the equilibrium self electric field is sufficiently weak. For the fundamental mode l1, however, stability properties are identical to those calculated from a macroscopic two-fluid model, and the growth rate is unaffected by the value of ion Larmor radius.
- Electricity and Magnetism
- Plasma Physics and Magnetohydrodynamics