Streamer evaporation

Streamer evaporation is the consequence of heating in ideal MHD models beca use plasma is weakly contained by the magnetic field. Heating causes inflat ion, opening of field lines, and release of solar wind. It was discovered i n simulations and, due to the absence of loss mechanisms, the ultimate end point is the complete evaporation of the streamer. Of course streamers do n ot behave in this way because of tosses by thermal conduction and radiation . Heating is also expected to depend on ambient conditions. We use a global MHD model with thermal conduction to examine the effect of changing the he ating scale height. We also extend an analytic model of streamers developed by Pneuman (1968) to show that steady streamers are unable to contain plas ma for temperatures near the cusp greater than similar to 2 X 10(6) K.