High-latitude pump-induced optical emissions for frequencies close to the third electron gyro-harmonic - art. no. 2112

摘要

1] It has been long established that high-power O-mode HF pumping of the ionosphere can produce artificial optical emissions. 630 nm O(D-1) 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. [References: 32