Relation between optical emissions, particles, electric fields, and Alfvén waves in a multiple rayed arc

Thomas J. Hallinan, J. Kimball, H. C. Stenbaek-Nielsen, K. Lynch, R. Arnoldy, J. Bonnell, P. Kintner

Research output: Contribution to journalArticlepeer-review

Abstract

Velocities of rays in auroral arcs were used to infer the perpendicular electric fields above the acceleration region. Using rocket measurements of electron energy as a proxy for the high-altitude potential, the high-altitude perpendicular electric fields were calculated and found to be in good agreement with those derived from the ray motions. Additionally, a 0.6 Hz oscillating electric field at high altitude was postulated on the basis of the passing rays. Such a field was also calculated from the electron energy measurements and was found to be closely related to an Alfvén wave measured on the payload following a delay of 0.8 s. The measured electron energy flux agreed well with the auroral luminosity down to scale sizes of about 10 km. The combination of ground-based imaging and the measured energy flux also allowed a determination of the lower border altitude of the arcs. They were found to be somewhat higher (130 km) than expected on the basis of the electron energy. A tall rayed arc with a lower border height of 170 km was associated with a burst of suprathermal electrons on the poleward edge of the aurora.

Original languageEnglish
Article number2000JA000321
Pages (from-to)15445-15454
Number of pages10
JournalJournal of Geophysical Research: Space Physics
Volume106
Issue numberA8
DOIs
StatePublished - Aug 1 2001

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