磁尾瓣区的场向电流

本文利用ISEE-2卫星的磁场和粒子资料(电子:75keVδ<1300keV,质子:170keVp<400keV),发现在磁尾远离等离子片的尾瓣区,常常同时探测到粒子脉冲和横向磁场扰动,表明有场向电流片存在。电流片的积分强度在3.3—21mA/m之间,与Frank等在磁尾等离子片边界上测量到的场向片电流积分强度可相比较。电流片总是成双成对,电流片的强度与AE指数或亚暴的关系密切。和磁层其他区域不同,在磁尾瓣区,经常探测到△B_x和△B_y同时存在,且△B_x和△B_y可相比拟的情形,它们可以用运动的线电流或不均匀密度的电流片来解释。 

Field-Aligned Current in the Magnetotail Lobe

It is found that the bursts of energetic particle (electron: 75 keV≤E_e≤1300 keV,proton: 170 keV≤E_p<400 keV) and east-west magnetic field perturbations are sometimes observed simultaneously by ISEE-2 satellite in the magnetotail lobe far from the plasma sheet,which shows that there are field-aligned currents in the magnetotail lobe.The integral densities of the current sheet range from 3.3 to 21 mA/m.These values are comparable to previous observations of field-aligned current made by Frank et al.on the plasma sheet boun-dary of the magnetotail.The current sheets always appear in pairs and their integral densities have a good correlation with AE index.Differing from the other regions,eastwest mag-netic field perturbations are sometimes accompanied by south-north ones.The fact can be explained through moving linear current model or heterogeneous density model of current sheet.