12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > High-latitude HF-induced airglow displaced equa...
View graph of relations

« Back

High-latitude HF-induced airglow displaced equatorwards of the pump beam

Research output: Contribution to journalJournal article

Published

Journal publication date09/2000
JournalGeophysical Research Letters
Journal number17
Volume27
Number of pages4
Pages2817-2820
Original languageEnglish

Abstract

HF-induced airglow at 630 nm was observed by the Digital All-sky Imager, located near Skibotn in Norway, at F-region altitudes above the EISCAT HF facility near Tromsø on 21 February 1999. The transmitter was operated in a 4-min on, 4-min off sequence at 4.04 MHz O-mode with the beam pointing vertically. The airglow reached a peak intensity of about 100 R above background and appeared equatorward of the HF beam’s projection on the reflection altitude, which was obtained from ionograms. Generally, the region of maximum airglow was displaced towards the magnetic field line (zenith angle = 12.8° S) passing through the HF facility. This is a unique feature of these observations. From mid-latitude studies, such airglow is thought to be excited either by electrons energised to several eV by plasma turbulence, or by thermal electron temperature enhancement. Such localisation towards the magnetic field is unexpected for both mechanisms of airglow generation and suggests this feature may be important at high latitudes.