Title: H alpha Surges in Solar Active Regions
Heesu Yang / Korea Astronomy and Space Science Institute
Solar H alpha surges are jets of cool chromospheric plasma, are protruding into the solar corona with the speed exceeding several tens of km/s. They are often observed in conjunction with magnetic reconnection phenomena such as Ellerman Bombs. In this presentation We focus on the studies of the triggering mechanisms and effects of the surges have been done using the Goode Solar Telescope at Big Bear Solar Observatory. Especially we present recent findings of the successive occurrence of 0.5'' wide photospheric vortices with strong transverse shear flows at the edge of a sunspot light bridge, and the subsequent ejection of chromospheric surges. The surges may result from either the magnetic tension generated after magnetic reconnection or an acoustic impulse of a fast photospheric transverse flow. Otherwise, the surges could also be associated with Alfvenic waves, in which case their origin could be torsional magnetic fields generated in the process of the vortex formation.