Beam-Driven Return Current Instability and Anomalous Plasma Heating in Solar Flares
Abstract
We consider the problem of ion-acoustic wave generation, and resultant anomalous Joule heating, by a return current driven unstable by a small-area thick-target electron beam in solar flares. With a prescribed beam current evolution, jb(t) (and, therefore, a prescribed return current jp(t) = −jb(t)), and using an approximate local treatment with a two component Maxwellian plasma, and neglecting energy losses, we demonstrate the existence of two quite distinct types of ion-acoustic unstable heating regimes. First, marginally stable heating occurs when the onset of instability occurs at electron-ion temperature ratios Te/Ti > 4.8. Secondly, there exists a `catastrophic' heating regime for which marginally stable evolution is impossible, when the onset of instability occurs at Te/Ti < 4.8.
- Publication:
-
Solar Physics
- Pub Date:
- September 1988
- DOI:
- 10.1007/BF00148730
- Bibcode:
- 1988SoPh..115..289C
- Keywords:
-
- Beam Currents;
- Magnetohydrodynamic Stability;
- Plasma Heating;
- Solar Flares;
- Solar Wind;
- Electron Beams;
- Electron Energy;
- Ion Acoustic Waves;
- Ohmic Dissipation;
- Resistance Heating;
- Wave Generation;
- Solar Physics;
- Flare;
- Solar Flare;
- Ohmic Heating;
- Thick Target;
- Heating Regime