VLA supporting observations for SOLAR-A

Abstract

High-resolution VLA maps at 20-cm wavelength can be used to resolve coronal loops within individual active regions and thereby reveal the coronal magnetic interaction that can trigger solar flares. These VLA maps can complement simultaneous SXT SOLAR-A observations. Simultaneous VLA and SOLAR-A observations can extend and amplify VLA results that resolve the preflare, impulsive and post-flare components of solar flares into nearby, but spatially-separated, sources. If this result is confirmed and found to be generally applicable, it will rule out previous theoretical work that confines all of these aspects of flare activity to a single coronal loop. VLA synthesis maps at 91.6-cm wavelength indicate that widely-separated active regions are apparently linked by large-scale, transequatorial magnetic loops 100 thousand to a million kilometers ( 2 to 20 arcminutes ) long. Three-second VLA snapshot maps at this wavelength suggest that energetic electrons, accelerated during a flare in one active region, can move within these global magnetic conduits at nearly the velocity of light, thereby triggering bursts along the large-scale loops or in distant active regions. The SXT telescope aboard SOLAR-A should routinely observe the entire Sun to sample these global magnetic structures. SXT or HXT SOLAR-A observations with a limited field of view within individual active regions should be compared with simultaneous, full-disk VLA observations that can connect the localized satellite results with related activity in distant regions.