On the Importance of Reverse Current Ohmic Losses in Electron-Heated Solar Flare Atmospheres,
Abstract
We consider the passage of a beam of non-thermal electrons through the flaring solar atmosphere, paying particular attention to the requirement that the beam be stable to the generation of plasma turbulence. We then compute the ratio of energy losses due to reverse current ohmic heating, and heating by Coulomb collisions, respectively, for the greatest flux which can pass stably through the atmosphere. We show that this ratio is determined by the low energy cutoff of the beam, by the electron temperature of the ambient atmosphere, and by the electron to ion temperature ratio theta. It is also independent of the atmospheric density. The results show that ohmic energy losses are undoubtedly important in the initial transient state, in agreement with other authors, but that their role is debatable in the flare atmosphere, depending on the value of theta appropriate. Expected values for theta during the impulsive phase of the flare indicate that reverse current ohmic energy losses, and their consequent effects on the electron beam dynamics and the hard X-ray bremsstrahlung emission, may not be as important as previously suggested; however, a fully time-dependent analysis of the beam-target interaction is necessary to fully resolve the issue. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1980
- Accession Number
- ADA101485
Entities
People
- A. Gordon Emslie
Organizations
- Stanford University