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A quantitative theory for terrestrial foreshock radio emissions
Author(s) -
Kuncic Z.,
Cairns I. H.,
Knock S.,
Robinson P. A.
Publication year - 2002
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 - 10.1029/2001gl014524
Subject(s) - physics , foreshock , flux (metallurgy) , earth radius , radiation , tangent , computational physics , plasma , magnetic field , atomic physics , astrophysics , magnetosphere , optics , nuclear physics , geology , quantum mechanics , seismology , aftershock , materials science , geometry , mathematics , metallurgy
We present the first quantitative theoretical results for the spatial distribution and flux levels of fundamental ( f p ) and second harmonic (2 f p ) plasma radiation generated in Earth's foreshock by beam‐driven Langmuir waves. The theory predicts that both the f p and 2 f p source regions typically extend over several hundred Earth radii ( R E ) along the tangent magnetic field line. In the direction perpendicular to the magnetic tangent, however, the source regions are more localized, with the peak emission confined to ≲10 R E for 2 f p radiation and ≲1 R E for f p radiation. The flux levels predicted by our model are in close agreement with the levels measured in situ by various spacecraft, with typical values ∼10 −14 W m −2 for 2 f p radiation. The f p flux densities are typically 2–3 orders of magnitude lower.