On the Current System and Electric Field Associated with the Boundary of Plasma Bubble

Tuesday, 16 December 2014
WeiJie Sun1, Suiyan Fu1, George K Parks2, Zuyin Pu1 and James A Slavin3, (1)Peking University, Beijing, China, (2)University of California Berkeley, Berkeley, CA, United States, (3)University of Michigan Ann Arbor, Ann Arbor, MI, United States
The current and electric fields associated with the dipolarization fronts (DFs, the leading edge of plasma bubble) have been investigated in the magnetotail plasma sheet using Cluster multi-point observations. We have studied each term in the generalized Ohm's law and showed that electric fields are directed normal to the DF in the magnetic dip region ahead of the DF as well as in the DF layer but in opposite directions in the plasma flow frame. The ions decouple from the magnetic field in the DF layer and dip region, whereas electrons remain frozen-in [Sun et al., 2014]. The field-aligned current on the DFs is similar to region-1-sense and is similar to region-2-sense just earthward of the boundary [Sun et al., 2013]. Further study has revealed a full picture of current system associated with the boundary of plasma bubble. Sun, W. J., et al. (2013), Field-aligned currents associated with dipolarization fronts, Geophys. Res. Lett., 40, 4503–4508, doi:10.1002/grl.50902. Sun, W.-J., et al. (2014), Electric fields associated with dipolarization fronts, J. Geophys. Res. Space Physics, 119, doi:10.1002/2014JA020045.