2013 Volume 8 Pages 2401130
Radial profile of floating potential inside the current sheet was measured for the purpose of investigating the two-fluid (Hall) effect during magnetic reconnection in the UTST merging experiment. During magnetic reconnection, the floating potential drop was formed spontaneously inside the current sheet, forming a steep electric potential gradient on its both downstream areas. Magnetic probe array measurement indicates that this potential drop appears spontaneously when the reconnection rate rapidly increase due to change in current sheet structure. The IDS probe measurement observed outflow almost equal to poloidal Alfvén speed in radial direction from the X-point, where steep gradient of floating potential is formed. This fact suggests that ion acceleration/heating is caused by the steep potential gradient formed in the downstream by magnetized electrons.