Assuming a single loop model during flare emission, continuous heating should give rise to multi-thermal plasma. This statement can only be debated if the thermalization time scale of the plasma is much smaller than heating time scale. So, there should be an time-integration limit for spectral analysis for iso-thermal and multi-thermal approximation.
What is your comment on this? How to estimate the thermalisation time?
To order of magnitude, an estimate of the thermalization time would be the inverse Ion-Electron Coulomb Collision frequency. The caveat is that this Coulomb Collision frequency is inversely proportional to the cube of the relative speed of the interacting particles, so you expect some runaway tails to pertain after this time yet you might think that they represent a small fraction of the electron population.
Thanks for your reply on this query. Kindly share a reference on the same. Thanks for your time.
Hello Arun
I think a number of books on plasma, see D. Nicholson's or Krall and Trievelpiece , to mention but two, include this comment although briefly. If memory serves, in Nicholson you will find the derivation of Coulomb Collision frequency as inversely proportional to the cube of the relative speed. Now the thermalization is brought up in the discussion whether a single fluid MHD is appropriate description of plasma (Ion-electron full thermalization) versus a two-fluid model or a kinetic approach. I think I have seen this in Chen also but I am not sure.
I hope this helps
Hi Neeraj,
Best wishes for your work on promoting information of the Sun through this quiz. How do you want to relate this questionnaire with the question I asked above?
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