Effect of finite ion gyroradius on the fire-hose instability in a high beta plasma

Journal Article · Thu Jul 01 04:00:00 EDT 1993 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860785· OSTI ID:6484955

Yoon, P H; Wu, C S; de Assis, A S ^[1]

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1. Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States)

In this paper, a generalized kinetic dispersion equation that supports various hydromagnetic waves and instabilities is derived. The general dispersion equation is derived under the usual assumption of hydromagnetic perturbations [i.e., [vert bar][omega][vert bar][sup 2][much lt][Omega][sub [ital i]][sup 2], and ([ital k][sub [ital z]][nu][sub A]/[Omega][sub [ital i]])[sup 2][much lt][beta][sub [parallel][ital i]], where [Omega][sub [ital i]] and [nu][sub A] are the ion gyrofrequency and Alfven speed, respectively, and [beta][sub [parallel][ital i]] is the parallel ion beta], but for arbitrary values of the quantity [lambda][sub [ital i]]=([ital k][sub [perpendicular]][rho][sub [perpendicular][ital i]])[sup 2]/2=([ital k][sub [perpendicular]][nu][sub A]/[Omega][sub [ital i]])[sup 2] [beta][sub [perpendicular][ital i]]/2 that appears in the dielectric tensor. Here, [rho][sub [perpendicular][ital i]] refers to the mean ion gyroradius, and [beta][sub [perpendicular][ital i]] is the perpendicular ion beta. Otherwise, the dispersion equation is fairly general with no additional approximation, such as ignoring certain off-diagonal dielectric tensor elements (which is usually done in the literature) employed. In the subsequent numerical analysis, special attention is paid to the fire-hose instability in a high beta plasma. The numerical results reveal that the conventional treatment of the fire-hose instability (i.e., taking zero ion gyroradius limit at the outset) is not adequate, and that the effect of finite ion gyroradius results in a significant enhancement of the growth rate over a large range of wave numbers.

• OSTI ID: 6484955
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 5:7; ISSN 0899-8221; ISSN PFBPEI
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
ALFVEN WAVES
CHARGED PARTICLES
DIELECTRIC TENSOR
DISPERSION RELATIONS
EQUATIONS
HIGH-BETA PLASMA
HOSE INSTABILITY
HYDROMAGNETIC WAVES
INSTABILITY
INSTABILITY GROWTH RATES
IONS
KINETIC EQUATIONS
PLASMA
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
TENSORS