Premium
Longitudinal variations of plasmapause radius and the propagation of VLF noise within small (ΔL ∼ 0.5) extensions of the plasmasphere
Author(s) -
Smith A. J.,
Carpenter D. L.,
Lester M.
Publication year - 1981
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/gl008i009p00980
Subject(s) - plasmasphere , whistler , physics , radius , earth radius , geophysics , noise (video) , computational physics , local time , electron , electron density , van allen radiation belt , magnetosphere , astrophysics , plasma , statistics , computer security , mathematics , quantum mechanics , artificial intelligence , computer science , image (mathematics)
Simultaneous broadband whistler recordings made during the International Magnetospheric Study (IMS) at the two Antarctic stations Halley and Siple have been used to study longitudinal variations in the radius of the plasmapause observed during local afternoon. In both of the two periods studied thus far, whistler‐derived equatorial electron density profiles imply an increase in plasmapause radius between the longitudes of Siple and Halley (Δϕ ∼ 30°) of ΔL ∼ 0.5. Intense VLF noise (∼2.5 kHz) was observed at Halley but not at Siple, and by echo analysis its propagation path was identified with that of a whistler component travelling close to the plasmapause within the region of larger radius. This leads to the conclusion that the noise was generated by a gyroresonance instability when energetic electrons (typically 10 keV), drifting eastwards in the plasmatrough, encountered enhanced plasma density in the small extension of the plasmasphere.