Sodankyla ̈ Geophysical Observatory Publications (2003) 92:7–10 High-Latitude Artificial Aurora from EISCAT: An Unique Phenomenon?

• Main Authors: M. J. Kosch, M. T. Rietveld, F. Honary, T. Hagfors
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: EISCAT
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.546.8875; http://eprints.lancs.ac.uk/6732/1/inproc_287.pdf

Abstract. The EISCAT HF-facility is capable of transmit-ting up to 210 MW of effective radiated power into the iono-sphere around 4 MHz. Beam swinging experiments have been undertaken with O- and X-mode transmissions. Dur-ing O-mode pumping soon after sunset, F-region electrons were accelerated sufficiently to excite the oxygen atoms, re-sulting in observable optical emissions. It has been found that the OD 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 pro-duced when HF-pumping is approximately along the mag-netic field line direction. This geometric phenomenon is pre-sented 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 arti-ficial aurora. 1