Wave Propagation in Pulsar Magnetospheres: Dispersion Relations and Normal Modes of Plasmas in Superstrong Magnetic Fields
Abstract
We derive the dispersion relations and polarization characteristics of the normal modes of radiation in superstrong magnetic fields, with particular attention to those attributes of importance to the transfer of radiation in the relativistic electron-positron plasmas expected to occur in the magnetospheres of radio pulsars. We restrict ourselves to the regions where the proper frequency of cyclotron resonance greatly exceeds the proper frequencies of the radiative normal modes. The normal modes are derived when the plasma has no momentum dispersion across the magnetic field but has arbitrary momentum dispersion along the field. The contribution of displacement current to the propagation of these "hydromagnetic" waves is consistently included. The distinction between superluminous and subluminous modes is made in the superstrong regime, where drift motions across the field are negligible, and useful formulae for the Landau damping of the subluminous branch of ordinary mode (the Alfven wave) are derived. These are used to set observational constraints on the geometry of the emission zone in radio pulsars, if the emission mechanism generates radiation in the form of subluminous waves. A brief discussion is given of the relevance of nonvacuum propagation to Razin suppression of bunched coherent curvature emission.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1986
- DOI:
- 10.1086/163978
- Bibcode:
- 1986ApJ...302..120A
- Keywords:
-
- Electron Plasma;
- Propagation Modes;
- Pulsar Magnetospheres;
- Pulsars;
- Relativistic Plasmas;
- Wave Dispersion;
- Wave Propagation;
- Computational Astrophysics;
- Landau Damping;
- Magnetic Flux;
- Magnetohydrodynamic Waves;
- Radiation Transport;
- Stellar Magnetic Fields;
- Astrophysics;
- HYDROMAGNETICS;
- POLARIZATION;
- PULSARS;
- RADIATION MECHANISMS