On the fundamental emission of type III solar radio bursts
Abstract
Radio emission from plasma waves which are generated by a beam of electrons and form nonlinear structures ('antennas' of finite size) is discussed. One-dimensional solitons emit negligible radiation at or near the plasma frequency, and can produce type III radio bursts only at the harmonic. However, fundamental emission at about 1.1 times the plasma frequency in the undisturbed medium (omegap) is possible if the plasma waves 'collapse' in 2 or 3 dimensions. It is estimated that emission from finite-sized plasma structures at 1.1 omegap yields a reasonable polarization, which is proportional to the Alfven speed, independent of the details of the emission process. The ratio of the polarizations in harmonic and fundamental emission for F-H pairs depends on the structure of the electron beam and should show strong center-limb dependence when it is in the observed range of values. A correlation between polarization and drift speed indicates that the plasma is at most marginally in the 2-D regime.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 1979
- Bibcode:
- 1979A&A....80..268W
- Keywords:
-
- Solar Physics;
- Solitary Waves;
- Type 3 Bursts;
- Electron Beams;
- Harmonic Radiation;
- Plasma Waves;
- Polarization Characteristics;
- Solar Physics