DETECTABILITY OF CHROMOSPHERIC EVAPORATION FRONTS IN SOLAR-FLARES

We compute the surface brightness distribution of the chromospheric ev aporation front during the flare impulsive phase in the pass-band of t he imaging Soft X-ray Telescope (SXT) on board Yohkoh. Hydrodynamic si mulations of the flaring plasma allow us to derive the evolution of de nsity and temperature distribution and therefore of emission distribut ion across the evaporation fronts. We show that SXT - as well as imagi ng X-ray telescopes with equivalent or better spatial and temporal res olution - should be able to detect clearly the front and follow its ev olution along the loop.