High latitude artificial aurora from EISCAT: An unique phenomenon?

Kosch, M. J. and Rietveld, M. T. and Honary, F. and Hagfors, T. (2001) High latitude artificial aurora from EISCAT: An unique phenomenon? In: 28th Annual European Meeting on Atmospheric Studies by Optical Methods, 1900-01-01.

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Abstract

The EISCAT HF-facility is capable of transmitting up to 210MW of effective radiated power into the ionosphere around 4 MHz. Beam swinging experiments have been undertaken with O- and X-mode transmissions. During O-mode pumping soon after sunset, F-region electrons were accelerated sufficiently to excite the oxygen atoms, resulting in observable optical emissions. It has been found that the O1D emission at 630 nm appears near the magnetic field aligned direction regardless of the HF transmitter beam pointing direction. This is not consistent with similar lower latitude observations. The strongest optical emission is produced when HF-pumping is approximately along the magnetic field line direction. This geometric phenomenon is presented for the first time and suggests that the magnetic field orientation is important for the mechanism of high-latitude artificial aurora. X-mode pumping does not produce an artificial aurora.

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