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New results on the generation of broadband electrostatic waves in the magnetotail
Author(s) -
Grabbe Crockett L.
Publication year - 1985
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/gl012i008p00483
Subject(s) - physics , magnetic field , computational physics , dispersion relation , whistler , electron , broadband , angular spectrum method , plasma sheet , dispersion (optics) , cutoff , plasma , frequency spectrum , cutoff frequency , spectrum (functional analysis) , noise (video) , low frequency , atomic physics , optics , magnetosphere , quantum mechanics , astronomy , artificial intelligence , diffraction , computer science , spectrum analyzer , image (mathematics)
The theory of the generation of broadband electrostatic noise in the magnetotail is extended through numerical solution of the dispersion relation under conditions that exist in the plasma sheet boundary layer. It is found that the low‐frequency portion of the spectrum has a broad angular spectrum but a fairly sharp peak near 75° with respect to the magnetic field, while the high‐frequency portion has a narrower angular spectrum that is strongly concentrated along the magnetic field line. These results are in excellent agreement with observations of the broadband wave spectrum and a recent measurement of the propagation direction. The effect of a second cold component of electrons is analyzed, and it is found that it can increase the upper cutoff frequency of BEN to the observed value at about the plasma frequency.