Ongoing Issues

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Revision as of 23:04, 13 May 2009 by Pshilaire (Talk | contribs)
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This page are notes I (P. Saint-Hilaire) took from the 2009/05/13 RHESSI ops meeting at Berkeley. It was designed to be improved and complemented by others. The idea is to write down ongoing issues in flare and SEP physics as they come to mind.

Contents

NUMBER PROBLEM


Pre-flare


Spectral issues


Type III emission


Gamma-rays


HXR footpoint issues

1. Timing: RHESSI should be able to do footpoint timing at the 0.1s level with visibilities (Hurford)

2. Flux ratios, spectral index differences: Double footpoint flares: do we have correlation between spectral index difference and flux ratios? --> Actually, some. Saint-Hilaire et al. (2008) have demonstrated that differences in column densities between leg of loops cannot explain all observed footpoint spectral index differences and flux ratios. Some other important mechanism is at play, most probably magnetic mirroring. Liu et al. (2008) basically agree, saying that neither a difference in column densities nor magnetic mirroring alone can explain all observations: we have interplay between the two (or there is even something else that comes into play).



Flare T, EM

Hottest temperatures in flares (45 MK) occur early in flare, at end of HXR emission (Neupert effect). EM goes on to rise and peaks much later (Caspi). In an event analysed by Saint-Hilaire et al. (2009), EM increases during more than 10 hours.


Neutral SEPs


Energetics


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