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High Temperature Gas Above Flares and Surges

Emission lines from very highly ionized iron have been observed during solar flares. The UVCS range includes [Fe XVIII] 974.9, [Fe XIX] 1118.1, and [Fe XXI] 1354.0, which are formed at log T = 6.8, 6.9 and 7.0, respectively. The aim of this proposal is to observe material ejected by flares and investigate the spatial distribution of very hot material above the flare. Line shape and shifts in the different parts of the source will allow mapping of the strong non-thermal velocity components which are expected in these events.

We will determine if hot plasma is observed, its spatial distribution and the upper limit of the region where hot material can be formed and transported in the corona. Hot plasma can be ejected at high velocity during flare phenomena in association with the impulsive phase. The Hard X-ray Imaging Spectrometer on SMM showed that very extended post-flare loops develop in the corona at the end of very intense flares. They expand at least up to 1.3 , maintaining flare temperatures ( 10 K) and relatively high density (2.5 10 cm).



Peter Smith
Fri Jan 17 12:11:15 EST 1997