Réme, H.: Observations of the cusp region under northward IMF

• Main Authors: F. Pitout, J. -m. Bosqued, W. F. Denig
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Svalbard; EISCAT
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.592.7461; http://hal.archives-ouvertes.fr/docs/00/32/92/20/PDF/angeo-19-1641-2001.pdf

Abstract. We present a comparative study of the cusp region using the EISCAT Svalbard Radars (ESR) and the Cluster spacecraft. We focus in this paper on 2 February 2001, over the time period from 07:30 UT to 12:00 UT when the oblique ESR antenna pointing northward at a low elevation recorded latitudinal motions of the cusp region in response to the IMF. Meanwhile, the Cluster satellites were flying over the EIS-CAT Svalbard Radar field-of-view around local magnetic noon. The spacecraft first flew near ESR, north-east of Sval-bard and then passed over the field-of-view of the antenna at about 11:30 UT. From 08:00 UT to 09:00 UT, the IMF re-mains primarily southward yet several variations in the Z-component are seen to move the cusp. Around 09:00 UT, an abrupt northward turning of the IMF moves the cusp region to higher latitudes. As a result, the Cluster satellites ended up in the northernmost boundary of the high-altitude cusp region where the CIS instrument recorded highly structured plasma due to ion injections in the lobe of the magnetosphere. Af-ter 09:00 UT, the IMF remains northward for more than two hours. Over this period, the ESR records sunward plasma flow in the cusp region due to lobe reconnection, while Clus-ter spacecraft remain in the high-altitude cusp. Key words. Magnetospheric physics (magnetopause, cusp, and boundary layers; plasma convection) Ionosphere (polar ionosphere) 1