The effects of an interplanetary shock on the high-latitude ionospheric convection during an IMF By-dominated period

• Published in: Annales geophysicae (1988) Vol. 26; no. 9; pp. 2937 - 2951
• Main Authors: COCO, I, AMATA, E, MARCUCCI, M. F, AMBROSINO, D, VILLAIN, J.-P, HANUISE, C
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau European Geophysical Society 01.09.2008; European Geosciences Union; Copernicus Publications
• Subjects: Earth Sciences; Earth, ocean, space; Exact sciences and technology; External geophysics; Geophysics; Physics; Physics of the ionosphere; Physics of the magnetosphere; Sciences of the Universe; Space Physics; Interplanetary magnetic field; High latitude; Orbit; Magnetopause; Convection flow; Ionosphere magnetosphere coupling; geomagnetic field; Shock front; Interplanetary shock wave; convection; magnetosphere; Interplanetary physics (Interplanetary shocks); Dynamic pressure; Reconfiguration; Magnetospheric physics (Magnetosphere-ionosphere interactions; Plasma convection); plasma convection; magnetospheric physics; magnetosphere-ionosphere interactions; interplanetary shocks; interplanetary physics
• ISSN: 0992-7689; 1432-0576
• DOI: 10.5194/angeo-26-2937-2008

On 6 January 1998 an interplanetary shock hit the magnetosphere around 14:15 UT and caused a reconfiguration of the northern high-latitude ionospheric convection. We use SuperDARN, spacecraft and ground magnetometer data to study such reconfiguration. We find that the shock front was tilted towards the morning flank of the magnetosphere, while the Interplanetary Magnetic Field (IMF) was By-dominated, with By<0, IMF Bz>0 and |By|>>Bz. As expected, the magnetospheric compression started at the first impact point of the shock on the magnetopause causing an increase of the Chapman-Ferraro current from dawn to dusk and yielding an increase of the geomagnetic field at the geostationary orbit and on the ground. Moreover, the high-latitude magnetometer data show vortical structures clearly related to the interaction of the shock with the magnetosphere-ionosphere system. In this context, the SuperDARN convection maps show that at very high latitudes above the northern Cusp and in the morning sector, intense sunward convection fluxes appear, well correlated in time with the SI arrival, having a signature typical for Bz>0 dominated lobe reconnection. We suggest that in this case the dynamic pressure increase associated to the shock plays a role in favouring the setting up of a new lobe merging line albeit |By| >> Bz ≥ 0.