The Micro Solar Flare Apparatus (MiSolFA)

Abstract:

During a solar flare the rapid release of magnetic energy drives extremely efficient particle acceleration through a mechanism which remains largely unknown. Hard X-ray observations are one of the most direct signatures of flare accelerated energetic electrons at and near the acceleration site, and X-ray spectra can provide key diagnostics to the physical processes occurring in flares. In particular, a measure of the electron angular distribution (the hard X-ray directivity) is a prime diagnostic of the unknown acceleration mechanism. However, to-date, observational constraints of directivity have not been clear. Looking towards the next solar cycle, stereoscopic X-ray observations of solar flares will make significant advances at measuring the hard X-ray directivity. The Micro Solar Flare Apparatus (MiSolFA) is a CubeSat Observatory that will observe solar flares at the same time as Solar Orbiter/STIX using cross-calibrated flight-spare detectors. During the rise of the next solar maximum, STIX on board Solar Orbiter will perform X-ray observations of solar flares from 0.28 AU (at perihelion) and up to inclinations of ∼25 degrees at heliospheric angles significantly different than the Earth. These two instruments working together will be the first pair of cross-calibrated X-ray spectrometers to observe solar flares from very different points of view allowing us to measure the anisotropy of the flare hard x-rays and finally confidently constrain the flare-accelerated electron directivity in individual flares for the first time.