A HYDRODYNAMIC MODEL OF THE IMPULSIVE PHASE OF A SOLAR-FLARE LOOP

With improvements in modeling of the chromospheric radiative loss and in the resolution of the transition region, together with the introduction of the mechanism of chromospheric heating by coronal soft X-rays, we have numerically simulated the hydrodynamic response of a solar flare loop to the thermal energy deposition around the top of the loop. Detailed evolutionary pictures have been obtained during the early stage of the impulsive phase for the conductively heated model, showing the fast heating of the flaring atmosphere, the formation and the development of chromospheric evaporation and condensation, the motion of the transition region, the consequences of the high-speed collision of evaporated material at the top, and so on. A comparison with previous work is also discussed.