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During the March 20-22, 1990, magnetic storm, Millstone Hill radar and DMSP satellite observations detailed the conditions surrounding the occurrence of a SAR arc which was observed continuously through an 8-hour interval from dusk till past midnight in the North American sector. All-sky imaging with a 630.0-nm imager continually monitored the(More)
The focus of the study is a region of enhanced ionospheric densities observed by the EISCAT Svalbard radar in the polar F-region near local magnetic noon under conditions of IMF B z <0. Multi-instrument observations, using optical, spacecraft and radar instrumentation, together with radio tomographic imaging, have been used to identify the source of the(More)
In this paper we focus on flux transfer events (FTEs) and poleward moving auroral forms (PMAFs) in the cusp region, combining data from the EISCAT Sval-bard radar, SuperDARN HF radars, ground-based optics, and three low-altitude polar-orbiting spacecraft. During an interval of southward interplanetary magnetic field the EISCAT Svalbard radar tracked a train(More)
Results are presented from a multi-instrument study of the spatial distribution of the summertime, polar ionospheric electron density under conditions of relatively stable IMF B z <0. The EISCAT Svalbard radar revealed a region of enhanced densities near magnetic noon that, when comparing radar scans from different local times, appeared to be spatially(More)
Spatial structures in ionospheric electron density revealed in a tomographic image have been identi®ed with auroral forms and related to their sources in precipitating particles observed by DMSP satellites. The observations of plasma enhancements relate to discrete auroral arcs seen in the post-noon sector, identi®ed by both red-and green-line emissions(More)
Annales Geophysicae Multi-site observations of the association between aurora and plasma convection in the cusp/polar cap during a southeastward (B y |B z |) IMF orientation Abstract. In a case study we demonstrate the spatiotemporal structure of aurora and plasma convection in the cusp/polar cap when the interplanetary magnetic field (IMF) B z < 0 and B y(More)
The Cluster spacecraft experienced several boundary layer encounters when flying outbound from the mag-netosphere to the magnetosheath in the dusk sector on 14 January 2001. The dayside boundary layer was populated by magnetosheath electrons, but not with quite as high densities as in the magnetosheath itself. The Cluster ground track was calculated using(More)
In a case study, we investigate transitions between fundamental magnetosphere–ionosphere (M-I) coupling modes during storm-time conditions (SYM-H between −100 and −160 nT) driven by an interplanetary coronal mass ejection (ICME). We combine observations from the near tail, at geostationary altitude (GOES-10), and electrojet activities across the auroral(More)