Supporting data for Favored Conditions for the Generation of Banded Hiss in

Using Van Allen Probes observations, we identify 4,096 plumes, 231 of which contain banded hiss, to investigate the favorable conditions for banded hiss generation. We find that the plumes mainly occur at L = 4.0-6.5 and MLT = 18-22, while banded hiss within plumes preferentially occurs at L = 4.5-6.5 and MLT = 13-17, with weaker geomagnetic fields than those in plumes without banded hiss at lower L-shells (L < 5.5).

These results indicate that the plume regions and a weak geomagnetic field are necessary for banded hiss excitation. Under such conditions, source electron anisotropies in the plume can provide free energy to generate the banded structure of hiss. Our study sheds new light on the overall generation mechanism of banded hiss and its potential role in radiation belt electron dynamics.</p>