Study of local reconnection physics in a laboratory plasma

A short review of physics results obtained in the Magnetic Reconnection Exp eriment (MRX) is given with an emphasis on the local features of magnetic r econnection in a controlled environment. Stable two-dimensional (2D) curren t sheets are formed and sustained by induction using two internal coils. Th e observed reconnection rates are found to be quantitatively consistent wit h a generalized Sweet-Parker model which incorporates compressibility. unba lanced upstream-downstream pressure, and the effective resistivity. The lat ter is significantly enhanced over its classical values in the low collisio nality regime. Strong local ion heating is measured by an optical probe dur ing the reconnection process, and at least half of the increased ion energy must be due to nonclassical processes, consistent with the resistivity enh ancement. Characteristics of high frequency electrostatic and electromagnet ic fluctuations detected in the current sheet suggest presence of the lower -hybrid-drift like waves with significant magnetic components. The detailed structures of current sheet are measured and compared with Harris theory a nd two-fluid theory.