Analysis On The Energy Release Process Of Small Space-time Scale Of A Magnetosphere Substorm

In this paper,we analysis the energy release process of small space-time scale of a magnetosphere substorm.The thesis is divided into three parts.The first part introduces the background and research signifance of magne-tosphere?s structure and substorm,and gives a brief introduction to THEMIS p-rogram and its related data.In the second part,a moderately intense substorm on 13 March 2008,fro-m 1040UT to 1210UT,observed by THEMIS probes and the Ground Based O-bservatory?GBO?is examined to analyse the global evolution of the substorm in the magnetotail.During this substorm,five THEMIS probes are arranged al-ong the X-axis in the vicinity of the midnight,from the radical distance of⁸.7Re to¹3.2Re.After the substorm onset,magnetic field dipolarization and plasma sheet expansions are all observed by different probes in the magnetotail.The average velocity of the plasma sheet expansions is 140km/s.Two types of dipolarization are detected in this substorm.The first type is?ipolarization front?which is associated wi-th the bursty bulkflow?BBF?.While the second type,which we call?global dipolariz-ation?,is associated with plasma sheet expansions.7 minutes later after the substrom onset,the occurrence of Pi2 pulsation can be observed at low,medium and high latit-udes.The amplitude of Pi2 pulsation gradually increases with the increase of latitude.The ion bulk velocity in the substorm event is mainly caused by the ion drift velocit-y,and the measured electric field is very likely to be the induced electric field gener-ated by the change of the local magnetic flux.The third part analyzes three substorm events.For the first time,the ano-malous resistance and the corresponding magnetic Reynolds number in the pro-cess of magnetic reconnection of the space plasma are calculated by using the data of the satellites.The calculation results show that:1?Abnormal resistivity varies greatly with time,the minimum up to 10³??8),the maximum up to 10¹²??8).The variation tendency of the anomalous resistivity obtained by the two computing methods is highly similar,and the magnitude of the two is close,but the magnitude of oscillation differs by one to two orders of magnitude.Magnetic Reynolds number also changes largely with time,the minimum up to 10;⁷/????,the maximum up to 10²/????.2?For different substorm events,the anomalous resistivity and its corresp-onding magnetic Reynolds number changes vary largely,indicating that the ma-gnitude of the anomalous resistivity is very likely to be related to the intensity of the substorm.