The Effect of Hot Protons on Magnetosonic Waves Inside and Outside the Plasmapause: New Observations and Theoretic Results

TitleThe Effect of Hot Protons on Magnetosonic Waves Inside and Outside the Plasmapause: New Observations and Theoretic Results
Publication TypeJournal Article
Year of Publication2018
AuthorsLiu, B, Li, L, Yu, J, Cao, J
JournalJournal of Geophysical Research: Space Physics
Date Published01/2018
Keywordsdamping of magnetosonic waves; growth of magnetosonic waves; magnetosonic waves; magnetospheric hot protons; Van Allen Probes; wave-particle interactions
AbstractBased on the wave and proton observations by Van Allen Probes A and B, we examined the effects of hot protons (0.01–50 keV) on fast magnetosonic (MS) waves inside and outside the Earth's plasmasphere. In the low-density plasma trough outside the plasmapause, the gyroresonance interactions between hot protons and MS waves not only cause the MS wave growth at some frequencies but also lead to the damping of MS waves at other frequencies, which depends on the proton phase space density gradient and the ambient plasma density. The gyroresonance of the observed hot protons cannot excite MS waves near the lower hybrid resonance frequency and even causes the MS wave damping. Thus, the frequencies of the observed MS waves outside the plasmapause are usually lower than the lower hybrid resonance frequency. In the high-density plasmasphere, the observed hot protons merely lead to the weak gyrodamping of MS waves. The persistent existence of lower band MS waves indicates that the weak gyrodamping effect of hot protons on MS waves is ignorable in the high-density plasmasphere.
URLhttp://onlinelibrary.wiley.com/doi/10.1002/2017JA024676/full
DOI10.1002/2017JA024676
Short TitleJ. Geophys. Res. Space Physics


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