Flow Streaming in the Magnetotail

Recently there has been renewed interest in the relationship between streaming flows in the magnetotail and observations in the auroral ionosphere. Therefore, we have investigated the earthward streaming of plasma in the magnetotail associated with magnetic reconnection by using the IPic3D implicit particle-in-cell simulation embedded in the UCLA global magnetohydrodynamic simulation of the solar wind interaction with the magnetosphere and ionosphere. In particular, we have investigated the flows of electrons and ions during a magnetospheric substorm on February 15, 2008. In the simulation, magnetotail reconnection began at 0348:38 UT in the pre-midnight tail at about XGSM= -32 R_E. Electrons from the reconnection region jetted earthward (V_xGSM » 700-800 km/s) and toward dawn (V_yGSM » 1500 km/s). The ions moved earthward at < 100 km/s and toward dusk at » 300 km/s. During the next minute, the location of reconnection moved tailward to X_GSM » -37 R_E. The earthward electron velocity at the reconnection site increased (V_xGSM > 900 km/s). However, closer to the Earth the electron velocity remained approximately constant (» 700-800 km/s), while the ion velocity increased to approximately the same value. This jetting of plasma resulted from a large E_x electric field (> 4.5 mV/m). The region of jetting electrons was in a narrow band (< 0.5 R_E in the north-south direction) that extended several R_E (2-10 R_E) from the reconnection site before the particles began moving along the separatrices. There are both all sky camera images and spherical equivalent current results available for this substorm and we will examine them for evidence of streaming and make general comparisons with the simulation results.