Properties of fast submillimeter time structures during a large solar flare

Abstract

We report properties of fast varying submillimeter emission during one of the strongest solar radio flares of solar cycle 23. Emission was obtained by the Solar Submillimeter-Wave Telescope at 212 and 405 GHz and compared with hard X-ray and γ-ray counts up to few tens of MeV photon energy ranges. We employ different methods to detect and characterize flux density variations and find that during the impulsive phase of the event, the closer in time to the peak flare, the higher the occurrence of the fastest and brightest time structures. The good comparison with hard X-ray and γ-ray count rates indicates that fast submillimeter pulses are the signatures of primary energetic injections. The characteristics of the fast spikes at 212 and 405 GHz, such as their flux density and localization, compared to those of the underlying slower impulsive component, also suggest that their nature is different.