CORRELATED FAST TIME STRUCTURES AT MILLIMETER WAVES AND HARD X-RAYS DURING A SOLAR BURST

Abstract

We present an analysis of the time profiles detected during a solar impulsive flare, observed at one-millimeter radio frequency (48 GHz) and in three hard X-ray energy bands (25- 62, 62-111, and 111-325 keV) with high sensitivity and time resolution. The time profiles of all emissions exhibit fast time structures of 200 - 300 ms half power duration which appear in excess of a slower component varying on a typical time scale of 10 s. The amplitudes of both the slow and fast variations observed at 48 GHz are not proportional to those measured in the three hard X-ray energy bands. However, the fast time structures detected in both domains are well correlated and occur simultaneously within 64 ms, the time resolution of the hard X-ray data. In the context of a time-of-flight flare model, our results put strong constraints on the acceleration time scales of electrons to MeV energies.