THE RESPONSE OF THE MAGNETOSPHERE TO AN INTERPLANETARY SHOCK GROUNDBASED
OBSERVATIONS OF THE SUDDEN IMPULSE ON SEPTEMBER 24

P. Chi, Guan Le, J. Raeder, C.T. RUSSELL, and E. Zesta (All at the Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA, email: pchi@igpp.ucla.edu; K. Yumoto, H. Kawano, and K. Kitamura (All at Kyushu University , Fukuoka, Japan; V. Angelopoulos (University of California, Berkeley, CA, USA): M. Moldwin (Florida Institute of Technology, FL, USA)

 

The strong interplanetary shock wave that intersected the front of the magnetosphere at about 2344 T on Sept 24, 1998 launched a compression of the magnetosphere that was followed around the world by a new generation of magnetometers with rapid sampling and precise GPS-synchronized timing. Magnetometers of these chains included those in the Circum Pan

Pacific Magnetometer Network, those in the IGPP/LANL array, those in the MEASURE array and those in the MACCS array. The event exhibited all the classical signatures of an SI including preliminary decrease before the main increase in the H-component. The ability to model this event and its induced ionospheric currents using an MHD code allows us to compare the compression as it is seen in the magnetosphere with the response of the ionospheric currents.