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Anisotropic proton instability magnetospheric (APIM) HISS: An introduction
Author(s) -
Parady B. K.
Publication year - 1974
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl001i006p00235
Subject(s) - hiss , physics , proton , instability , anisotropy , van allen probes , nuclear magnetic resonance , computational physics , magnetosphere , van allen radiation belt , optics , nuclear physics , electron , plasma , mechanics
It is proposed that some plasmaspheric ELF hiss is generated by ring current protons. The mechanism by which waves are generated is the Anisotropic Proton Instability Magnetospheric (APIM) Hiss mechanism. APIM hiss (with a frequency close to the lower hybrid resonance frequency) is a loss‐cone, flute instability arising from proton velocity space anisotropies. The energy driving the waves comes from the free energy of the "inverted population" of the proton loss‐cone distribution. The APIM hiss mechanism predicts the bandwidth, center frequency, source location, and wave normal angle of some types of plasmaspheric hiss. In addition, variation in intensity with proton anisotropies and fluxes are predicted. APIM hiss is suggested as a possible additional loss mechanism for ring current protons.