Alfven waves in the corona above sunspots

Abstract

From the line width in coronal arches above sunspots it is possible to estimate the amount of Alfven wave flux escaping from the spot into the solar corona. It is found to be less than 4 x 10 to the 7th ergs/sq cm/s in the corona just above the spot, which is less than 0.08% of the missing spot flux. If the Alfven-wave cooling mechanism for spots is to be valid, these waves have therefore to escape downward into the solar interior.