The CME’s structure of solar wind(interplanetary magnetic field)is different from CIR’s.The two processes in which plasma and solar wind energy are injected into the Earth’s inner magnetosphere are not the same.So,the variations of energetic elec- trons flux in the radiation belts are different between the storms associated with CMEs and CIRs.By using data from SAMPEX(Solar,Anomalous,and Magnetospheric Particle Explorer)satellite,we have investigated the dynamic variations of the outer radiation belt for 1.5–6.0 MeV electrons during 54 CME-driven storms and 26 CIR-driven recurrent storms.According to the superposed epoch analysis,for CME-and CIR-driven storms,when the Dst index reaches the minimum,the locations of the outer boundary move to L=4 and L=5.5,respectively.In the recovery phases,the locations of the outer boundary of the outer radiation belt are generally lower than and slightly higher than those before CME-and CIR-driven storms,respectively.We have found that the logarithmically decaying 1/e cut-off L-shell is a satisfying indicator of the outer boundary of the outer radiation belt.Furthermore,our study shows that the logarithmically decaying 1/e cut-off latitude is dependent on the Kp index in the main phases of CME-and CIR-driven storms,while in the recovery phases,there is no obvious correlation.In ad- dition,it has been shown that the locations of the peak electron flux are controlled by the minimum Dst index in the main phases of CME-driven storms.The influences of multiple storms on the electron flux of outer radiation belt have also been in- vestigated.
Nose event,which names after the nose-like shape of structures in ion spectrograms observed by satellite in the inner magnetosphere,refers to the deep inward penetration of ions from magnetotail at discrete energy bands.Nose events have been studied extensively both with observations and simulations since first discovered in 1970s.In this study we use the UBK method to model the different L-shell penetration characteristics for a multi-band nose event observed by Cluster/CODIF on April 11,2002.The modeled open-closed orbit separatrices are generally smaller than the observed L-shell penetrations for outbound crossing;the difference varies from 2.02 to 0.62 R E for different energy channels of H + bands and from 1.88 to 1.10 R E for O + band.The average difference is 1.46 R E.The separatrices for the inbound crossing are generally larger than those of outbound crossing and are more consistent with the observed L-shell penetration depths.The modeled open-closed orbit separatrices are smaller than the observed L-shell penetrations for 6.5-17.1 keV energy channels of H + bands but larger for 4.0-5.1 keV(due to closed banana orbits region) and 21.7-35.2 keV(due to energy increasing) energy channels of H + bands.For O + band,the difference between the modeled open-closed orbit separatrix and observed L-shell penetrations of 4.6 keV energy channel is larger(due to closed banana orbits region),the difference of 7.4 keV energy channel is smaller.The overall average difference is 0.043 R E for nose structures of inbound crossing.The discrepancies between the model and observation may come from the magnetic field and electric potential models we used.The formation of multi nose event and relations to the observed plasma flow vortices are discussed,the local intense E Y may relate to the formation of the observed multi nose structures.
