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High-latitude pump-induced optical emissions for frequencies close to the third electron gyro-harmonic

Research output: Contribution to Journal/MagazineJournal articlepeer-review

<mark>Journal publication date</mark>10/12/2002
<mark>Journal</mark>Geophysical Research Letters
Issue number23
Number of pages4
Pages (from-to)2112-2115
Publication StatusPublished
<mark>Original language</mark>English


It has been long established that high-power O-mode HF pumping of the ionosphere can produce artificial optical emissions. 630 nm O(1D) 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.