Ground-based and satellite observations of high-latitude auroral activity in the dusk sector of the auroral oval

• Main Authors: Kauristie, K., Pulkkinen, T. I., Amm, O., Viljanen, A., Syrjäsuo, M., Janhunen, P., Massetti, S., Orsini, S., Candidi, M., Watermann, J., Donovan, E., Prikryl, P., Mann, I. R., Eglitis, P., Smith, C., Denig, W. F., Opgenoorth, H. J., Lockwood, M., Dunlop, M., Vaivads, A., André, M.
• Other Authors: Geophysical Research Division Helsinki, Finnish Meteorological Institute (FMI), National Research Council of Italy, Danish Meteorological Institute (DMI), University of Calgary, Communications Research Centre Canada (CRC), University of York York, UK, Swedish Institute of Space Physics Kiruna (IRF), Bartol Research Institute, Air Force Research Laboratory (AFRL), United States Air Force (USAF), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Imperial College London
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2001
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Ny-Ålesund; Ny Ålesund
• Online Access: https://hal.science/hal-00316959; https://hal.science/hal-00316959/document; https://hal.science/hal-00316959/file/angeo-19-1683-2001.pdf

International audience On 7 December 2000, during 13:30?15:30 UT the MIRACLE all-sky camera at Ny Ålesund observed auroras at high-latitudes (MLAT ~ 76) simultaneously when the Cluster spacecraft were skimming the magnetopause in the same MLT sector (at ~ 16:00?18:00 MLT). The location of the auroras (near the ionospheric convection reversal boundary) and the clear correlation between their dynamics and IMF variations suggests their close relationship with R1 currents. Consequently, we can assume that the Cluster spacecraft were making observations in the magnetospheric region associated with the auroras, although exact magnetic conjugacy between the ground-based and satellite observations did not exist. The solar wind variations appeared to control both the behaviour of the auroras and the magnetopause dynamics. Auroral structures were observed at Ny Ålesund especially during periods of negative IMF B Z . In addition, the Cluster spacecraft experienced periodic ( T ~ 4 - 6 min) encounters between magnetospheric and magnetosheath plasmas. These undulations of the boundary can be interpreted as a consequence of tailward propagating magnetopause surface waves. Simultaneous dusk sector ground-based observations show weak, but discernible magnetic pulsations (Pc 5) and occasionally periodic variations ( T ~ 2 - 3 min) in the high-latitude auroras. In the dusk sector, Pc 5 activity was stronger and had characteristics that were consistent with a field line resonance type of activity. When IMF B Z stayed positive for a longer period, the auroras were dimmer and the spacecraft stayed at the outer edge of the magnetopause where they observed electromagnetic pulsations with T ~ 1 min. We find these observations interesting especially from the viewpoint of previously presented studies relating poleward-moving high-latitude auroras with pulsation activity and MHD waves propagating at the magnetospheric boundary layers.