On the marginal instability threshold condition of the aperiodic ordinary mode

Journal Article · Tue Jul 15 04:00:00 EDT 2014 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4890463· OSTI ID:22299810

Schlickeiser, R. ^[1]; Yoon, P. H. ^[2]

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1. Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- and Astrophysik, Ruhr-Universität, 44780 Bochum (Germany)
2. Institute for Physical Science and Technology, University of Maryland, College Park, 20742 Maryland (United States)

The purely growing ordinary (O) mode instability has recently received renewed attention owing to its potential applicability to the solar wind plasma. Here, an analytical marginal instability condition is derived for counter-streaming bi-Maxwellian plasma particle distribution functions. The derived marginal instability condition as a function of the temperature anisotropy and plasma beta agrees remarkably well with the numerically determined instability condition. The existence of a new instability domain of the O-mode at small plasma beta values is confirmed with the leading A∝β{sub ∥}{sup −1}-dependence, if the counter-stream parameter P{sub e} exceeds a critical value. At small plasma beta values at large enough counter-stream parameter, the O-mode also operates for temperature anisotropies A = T{sub ⊥}/T{sub ∥} > 1 even larger than unity, as the parallel counter-stream free energy exceeds the perpendicular bi-Maxwellian free energy.

• OSTI ID: 22299810
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 21; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANISOTROPY
DISTRIBUTION FUNCTIONS
FREE ENERGY
PARTICLES
PLASMA
SOLAR WIND