Kinetic Alfvén waves in extended radio sources
Abstract
Electric current generation by kinetic Alfvén waves (KAW) is discussed for the case of extended radio sources (ERS), in particular, extragalactic jets (EJ). These currents are generated parallel to the background magnetic field due to Landau damping by which KAW accelerate electrons. We find that the KAW generated currents are in excess of the currents necessary for an EJ to be magnetically selfconfined. We address the problem of determining the process that can maintain ERS inhomogeneous. We study the stability of a plasma which has: (1) the average local current density due to KAW given by our calculations; (2) the average local electrical conductivity (anomalous) due to KAW indicated by our calculations and the calculations of Hasegawa and Mima (1978); and (3) wave heating by surface Alfvén waves, independent of plasma temperature. We show that this plasma is subject to the thermal Joule instability. We suggest the thermal Joule instability as the process that maintains ERS inhomogeneous. Our KAW analysis correlates the important problems of ERS of (re)acceleration, current generation, collimation, and maintenance of inhomogeneities.
 Publication:

Astrophysics and Space Science
 Pub Date:
 November 1987
 DOI:
 10.1007/BF00642860
 Bibcode:
 1987Ap&SS.138...23J
 Keywords:

 Current Density;
 Electron Acceleration;
 Landau Damping;
 Magnetohydrodynamic Stability;
 Magnetohydrodynamic Waves;
 Radio Sources (Astronomy);
 Electrical Resistivity;
 Magnetic Fields;
 Plasma Temperature;
 Astrophysics