Abstract 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 Alfvén waves. Using MHD equations, modified to account self-consistently for the various exchanges of energy and momentum between the four components, we present the wave equation governing the propagation of long wavelength compressive perturbations of the system. It is found that backward propagating slow magnetoacoustic waves can be driven unstable by the pressure of the self-excited Alfvén 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 dynamical effect of cosmic rays and Alfvén waves on the structure of the galactic halo, are briefly discussed.


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    Title :

    Magnetoacoustic instability driven by Alfvén waves excited by cosmic rays


    Contributors:
    McKenzie, J.F. (author) / Webb, G.M. (author)

    Published in:

    Advances in Space Research ; 4 , 2-3 ; 219-223


    Publication date :

    1984-01-01


    Size :

    5 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



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