Midday auroral breakup events and related energy and momentum transfer from the magnetosheath

• Main Authors: M. Lockwood, Z T. Oguti, S. W. H. Cowley, K. S. C. Freeman, B. Lybekk, D. M. Willis A
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1990
• Subjects: EISCAT
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.694.7951; http://www.eiscat.rl.ac.uk/Members/mike/publications/pdfs/1990/64_Sandholtetal_1990.pdf

Abstract. Combined observations by gions. The filamentary spatial structure meridian-scanning photometers, all-sky and the spectral characteristics of the auroral TV camera and the EISCAT radar optical signature indicate associated permitted a detailed analysis of the localized ~ 1-kV potential drops between temporal and spatial development of the the magnetopause and the ionosphere midday auroral breakup phenomenon and the during the most intense auroral events. related ionospheric ion flow pattern The duration of the events compares well within the 71ø-75 ø invariant latitude with the predicted characteristic times radar field of view. The radar data of momentum transfer to the ionosphere revealed dominating northward and west- associated with the flux transfer event-ward ion drifts, of magnitudes close to related current tubes. It is suggested the corresponding velocities of the that, after this 2-10 min interval, the discrete, transient auroral forms, during sheath particles can no longer reach the the two different events reported here, ionosphere down the open flux tube, due characterized by IMF IBy/Bzl < 1 and> 2, to the subsequent super-Alfv6nic flow