Long-duration exohiss waves outside the plasmasphere: observed by Van Allen Probes
Thursday, 18 December 2014
We report an exohiss event in the low-density trough region observed by Van Allen Probes on 2 February 2014. These exohiss waves are discovered in the wide MLT distribution [9.1,13.4] and low magnetic latitude, with narrow-band structure and weak intensity compared with plasmaspheric hiss. Using the Continue Waveform Burst Mode data and MAG data on the EMFISIS, we analyze the normal angle, electromagnetic planarity and anti~/parallel-propagating Poynting flux of exohiss wave. The results show indicate that exohiss waves are the result of plasmaspheric hiss leakage into the trough region. The dependence of the proportion of anti~/parallel-propagating Poynting flux on MLT can be explained by Landau damping associated with suprathermal eletrons.