Compressional instability in the solar wind driven by wave dissipation

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA01834· OSTI ID:5261826

Dougherty, M K ^[1]; McKenzie, J F ^[2]

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1. Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)
2. Max-Planck-Institut fuer Aeronomie, Katlenburg-Lindau (Germany)

In this paper, the authors examine the stability of a steady solar wind dissipatively heated by Alfven waves whose relative amplitude is saturated at a given level by nonlinear processes. It is shown that long-wavelength compressional modes can be driven unstable by dissipative heating arising from short-wavelength saturated Alfven waves. Analytic expressions are derived for the marginal stability condition and the growth rates in the unstable region for the case of a moderate to low {beta} plasma. These are supplemented by a numerical solution of the full MHD dispersion equation, including dissipative Alfvenic effects, which confirms the approximate analysis. It is shown that the growth time of the instability can be of the order of 7 times the characteristic period of an Alfven wave for a wide range of parameters appropriate to the solar wind. The implication is that the compressional instability driven by dissipative Alfven waves could play a significant role in the large-scale heating and dynamics of the solar wind, particularly in the supersonic region.

• OSTI ID: 5261826
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A1; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
ANALYTICAL SOLUTION
COMPRESSION
DYNAMICS
FLUID FLOW
FLUID MECHANICS
HEATING
HYDRODYNAMICS
HYDROMAGNETIC WAVES
INSTABILITY
LOW-BETA PLASMA
MAGNETOHYDRODYNAMICS
MECHANICS
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
PLASMA
RADIATION PRESSURE
SOLAR ACTIVITY
SOLAR WIND
SUPERSONIC FLOW