The existence of an ultrarelativistic plasma beyond the Alfvén cylinder of a pulsar.
Abstract
The relativistic theory of MHD shocks is employed to determine the state of the plasma across the shock discontinuity believed to exist at the critical Alfvenic surface of the flow in pulsar magnetospheres. Gradients in the plasma variables at the Alfven cylinder are analyzed along with shock relations in relativistic MHD theory. The expression derived for the mean particle energy of the shocked plasma is rewritten in terms of variables which are more directly related to the known properties of pulsars. It is found that a considerable fraction of the magnetic energy of the plasma crossing the shock is thermalized and that the available magnetic energy per particle at the Alfven cylinder is about 10 million GeV, to within an order of magnitude. It is concluded that in terms of energy, this plasma can be regarded as being responsible for a pulsar's radiation and can be identified as an efficient and relatively permanent source of cosmic rays.
 Publication:

The Astrophysical Journal
 Pub Date:
 June 1976
 DOI:
 10.1086/154445
 Bibcode:
 1976ApJ...206..822A
 Keywords:

 Magnetohydrodynamics;
 Plasma Cylinders;
 Pulsar Magnetospheres;
 Pulsars;
 Relativistic Plasmas;
 Shock Waves;
 Flow Velocity;
 Particle Energy;
 Quartic Equations;
 Shock Wave Interaction;
 Stellar Atmospheres;
 Stellar Radiation;
 Astrophysics