A Statistical Study of Lower Hybrid Waves in the Earth's Magnetosphere by Van Allen Probes

The lower hybrid (LH) waves are electrostatic emissions near the LH resonant frequency. They propagate perpendicularly with a small wavelength comparable to Larmor radius of thermal particles and can be capable of heating both ions and electrons. In this study, we statistically study the global distribution of LH waves in the inner magnetosphere by using Van Allen Probes observation from 2012 to 2018. We find that (a) LH waves are commonly observed in the inner magnetosphere. Most LH waves are confined near the magnetic equator with typical amplitudes of 0.02-0.2 mV/m and occurrence rates up to 10%. (b) LH waves extend to inner L regions with increasing wave amplitudes as AE* increases. (c) Weak LH waves occur at the nightside inside the plasmapause. Moderate and strong LH waves occur at the nightside and noon inside the plasmapause. As AE* increases, they extend to all magnetic local times inside the plasmapause and dawnside outside the plasmapause.

Automated summary

In this study, the global distribution of lower hybrid (LH) waves in the inner magnetosphere was statistically studied using Van Allen Probes observations from 2012 to 2018. It was found that LH waves are commonly observed near the magnetic equator with typical amplitudes of 0.02-0.2 mV/m and occurrence rates up to 10%. The waves extend to inner L regions with increasing amplitudes as AE* increases, and weaker waves are observed at the nightside inside the plasmapause while moderate and strong waves are observed at the nightside and noon inside the plasmapause. They extend to all magnetic local times inside the plasmapause and dawnside outside the plasmapause with increasing AE*.