Instabilities, Wave Emission, and Energy Transport along Bursty Bulk Flows and Supra-arcade Downflows: Differences, Similarities, and Effects on the Surrounding Regions

Abstract We examine the stability conditions for two posteruptive phenomena in the solar–terrestrial environment, namely, bursty bulk flows (BBFs) in the Earth’s magnetotail and supra-arcade downflows (SADs) in the solar corona. We investigate the possibility of Kelvin–Helmholtz instability (KHI) and magnetohydrodynamic (MHD) wave emission along these two shear flow regions that have striking similarities. Our results suggest that the KHI and emission of propagating MHD waves due to KHI are possible along both SADs and BBFs with varying strengths depending on the background plasma parameters. These waves offer a means of energy transport out of SADs and BBFs. In the case of SADs, KHI-emitted MHD waves may transport energy into the surrounding regions and contribute to solar coronal heating. In the case of BBFs, KHI waves may influence the magnetosphere–ionosphere coupling in the near-Earth magnetotail regions by enhancing particle injections, auroral brightenings, and field-aligned currents. Moreover, the reduction of the kinetic energy of the flows arising from the emission of MHD waves may contribute to the braking of both SADs and BBFs.