Magnetoacoustic instability driven by Alfven waves excited by cosmic rays

Conference · Sun Jan 01 04:00:00 EST 1984 · Adv. Space Res.; (United States)

OSTI ID:5822214

Mckenzie, J F; Webb, G M

This paper analyzes the question of the stability of a four component system consisting of a magnetic field embedded in a thermal plasma in the presence of cosmic rays and Alfven waves. Using MHD equations, modified to account self-consistently for the various exchanges of energy and momentum between the four components, the wave equation governing the propagation of long wavelength compressive perturbations of the system is presented. It is found that backward propagating slow magnetoacoustic waves can be driven unstable by the pressure of the self-excited Alfven waves. Marginal stability curves in a suitably defined parameter space are given as well as sample calculations of the growth rate in the unstable regime. Possible applications of this instability to astrophysical situations, such as the cosmic ray shock problem and the dynamic effect of cosmic rays and Alfven waves on the structure of the galactic halo, are briefly discussed. 14 references.

• Research Organization: Natal Univ., Durban, Republic of South Africa
• OSTI ID: 5822214
• Report Number(s): CONF-8406167-
• Conference Information: Journal Name: Adv. Space Res.; (United States) Journal Volume: 4
• Country of Publication: United States
• Language: English

Related Subjects

640430* -- Fluid Physics-- Magnetohydrodynamics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACOUSTICS
ALFVEN WAVES
COSMIC RADIATION
DIFFERENTIAL EQUATIONS
EQUATIONS
HOT PLASMA
HYDROMAGNETIC WAVES
INTERACTIONS
IONIZING RADIATIONS
MAGNETOACOUSTICS
PARTIAL DIFFERENTIAL EQUATIONS
PERTURBATION THEORY
PLASMA
RADIATIONS
SHOCK WAVES
WAVE EQUATIONS