Magnetic Flux Closure Directly Induced by Interplanetary Shocks: Observations Using IMAGE-FUV and SuperDARN, and Modelling With GUMICS-4.
Hubert, Benoît ; ; et al
Poster (2005, December 01)
A method has been developed to monitor the dayside and nightside reconnection rates using FUV remote sensing of the proton aurora and ionospheric convection patterns. Global images of the proton aurora ... [more ▼]
A method has been developed to monitor the dayside and nightside reconnection rates using FUV remote sensing of the proton aurora and ionospheric convection patterns. Global images of the proton aurora are obtained using the SI12 instrument of the FUV experiment on board the IMAGE satellite, and used to identify the open/closed (o/c) field line boundary. SuperDARN data are used to determine the ionospheric convection velocity, and the associated electric field. The dayside and nightside reconnection voltages are then determined accounting for the ionospheric electric field and the motion of the o/c boundary. This method is used to compute the dayside and nightside reconnection voltages during two interplanetary shocks for which the IMF was mostly northward, so that the amount of open magnetic flux was so small that no significant substorm expansion phase could develop. The flux closure voltage shows a sharp signature when the interplanetary shocks sweep by the nightside magnetosphere. MHD simulations conducted using the GUMICS-4 model for similar conditions show a similar signature in the nightside flux closure rate. We suggest that this flux closure event is directly induced by the compression of the magnetotail. [less ▲]Detailed reference viewed: 6 (0 ULg)