Simultaneous optical and radar signatures of poleward-moving auroral forms

• Published in: Annales Geophysicae
• Main Authors: Thorolfsson, A., Cerisier, J. C., Lockwood, M., Sandholt, P. E., Senior, C., Lester, Mark
• Format: Conference Object
• Language: English
• Published: European Geosciences Union (EGU), Copernicus Publications, Springer Verlag (Germany) 2015
• Subjects: Science & Technology; Physical Sciences; Astronomy & Astrophysics; Geosciences; Multidisciplinary; Meteorology & Atmospheric Sciences; Geology; ionosphere; auroral ionosphere; plasma convection; magnetospheric physics; magnetopause; cusp and boundary layers; FLUX-TRANSFER EVENTS; MAGNETOSPHERE-IONOSPHERE SYSTEM; MAGNETIC-FIELD ORIENTATION; BOUNDARY-LAYER CAMPAIGN; MULTIPLE BRIGHTENINGS; DAYSIDE MAGNETOPAUSE; ENHANCED CONVECTION; HF-RADAR; CUSP; RECONNECTION; Ny-Ålesund; Svalbard; EISCAT; Ny Ålesund
• Online Access: http://www.ann-geophys.net/18/1054/2000/angeo-18-1054-2000.html; http://hdl.handle.net/2381/31900; https://doi.org/10.1007/s00585-000-1054-2

Dayside poleward moving auroral forms (PMAFs) were detected between 06:30 and 07:00 UT on December 16, 1998, by the meridian scanning photometer and the all-sky camera at Ny Ålesund, Svalbard. Simultaneous SuperDARN HF radar measurements permitted the study of the associated ionospheric velocity pattern. A good general agreement is observed between the location and movement of velocity enhancements (flow channels) and the PMAFs. Clear signatures of equatorward flow were detected in the vicinity of PMAFs. This flow is believed to be the signature of a return flow outside the reconnected flux tube, as predicted by the Southwood model. The simulated signatures of this model reproduce globally the measured signatures, and differences with the experimental data can be explained by the simplifications of the model. Proposed schemes of the flow modification due to the presence of several flow channels and the modification of cusp and region 1 field-aligned currents at the time of sporadic reconnection events are shown to fit well with the observations. Peer-reviewed Publisher Version 9th International EISCAT Workshop, WERNIGERODE, GERMANY