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Title: On the marginal instability threshold condition of the aperiodic ordinary mode

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.
Authors:
 [1] ;  [2] ;  [3]
  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)
  3. (Korea, Republic of)
Publication Date:
OSTI Identifier:
22299810
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANISOTROPY; DISTRIBUTION FUNCTIONS; FREE ENERGY; PARTICLES; PLASMA; SOLAR WIND