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High‐latitude pump‐induced optical emissions for frequencies close to the third electron gyro‐harmonic
Author(s) -
Kosch M. J.,
Rietveld M. T.,
Kavanagh A. J.,
Davis C.,
Yeoman T. K.,
Honary F.,
Hagfors T.
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 - 10.1029/2002gl015744
Subject(s) - langmuir turbulence , physics , ionosphere , electron , backscatter (email) , harmonic , computational physics , turbulence , photon , f region , radar , optics , atomic physics , plasma oscillation , geophysics , mechanics , acoustics , nuclear physics , telecommunications , computer science , wireless
It has been long established that high‐power O‐mode HF pumping of the ionosphere can produce artificial optical emissions. 630 nm O( 1 D) photons are produced by pump‐accelerated electrons colliding with the F‐layer neutral oxygen. However, the mechanism for artificial electron acceleration remains unclear. Competing theories include Langmuir and upper‐hybrid turbulence. Pump‐induced HF coherent radar backscatter power is closely linked with upper‐hybrid turbulence, both of which are known to reduce when pumping on an electron gyro‐harmonic frequency. On 3 November 2000, the EISCAT HF facility was systematically stepped in frequency through the 3rd gyro‐harmonic. A significant reduction in the artificial optical intensity coincides with that of CUTLASS radar backscatter power. This is conclusive proof that upper‐hybrid turbulence is intimately linked to the mechanism for high‐latitude pump‐induced aurora, at least for 630 nm photons and the steady state.