Origin of the soft X-ray emission after the impulsive phase of the March 26, 1991 solar flare

This study is based on the GOES soft X-ray measurements in two energy bands for the March 26, 1991 solar flare. The hard gamma-ray measurements during this flare suggest an additional energy release after the impulsive phase (Akimov et al. 1994). The X-ray data are used to determine the time behavior of the temperature and emission measure in the gamma-ray source for the entire event. Based on a numerical solution of the system of gas-dynamical equations, we consider the energy balance in the source. We have found that the observed time behavior of the temperature in the second flare phase can be modeled only by assuming that there is additional heating of the upper part of the loop. The density at the top of the loop is 3 x 10¹⁰ cm^-3.