THE DYNAMICS OF DAYSIDE AND NIGHTSIDE AURORAS OVER SVALBARD

摘要

Aurora is the most spectacular optical visualisation of solar events. Svalbard, due to the location in the high Arctic, is a favourable and unique platform to observe two main forms of aurora: dayside and nightside. Dayside cusp auroras are mainly controlled by the interplanetary magnetic field (IMF) Bz component, which can reconnect with the Earth magnetic field and enable low energy particles to reach the ionosphere and excite atmospheric species. The most significant pattern of nightside aurora is the substorm that is generated by tail reconnection and can be regarded as a process, which releases energy from the central plasma sheet and high-energy radiation belts. On the 1st of January 2004 both dayside and nightside auroras were observed over Svalbard. The Meridian Scanning Photometer (MSP) at the Auroral Station in Adventdalen (78,20 N, 15,84 E) measured intense dayside aurora during the daytime and two big substorms pre and post local magnetic midnight. The data from the MSP were supported by magnetometer data and satellite data from ACE and NOAA Space Environment Center. In this paper the dynamics of the solar plasma for the energetic particles precipitating into Earth's magnetosphere/ionosphere system on the 1st of January 2004 is discussed. Both satellite and ground based measurements are analysed together to obtain the most complete result.