Fine scale structure in the current sheet and electrostatic fields during driven magnetic reconnection on the VTF experiment.

We have conducted a series of experiments in the VTF reconnection experiment[1] to measure with high resolution the current channel and electric structures that form in response to driven reconnection. Preliminary measurements have revealed that the current sheet is not symmetric across the X-line, contradicting an assumption fundamental to nearly every reconnection theory. Importantly, effects related to this asymmetry can account for momentum balance for the electrons at the X-line (i.e. fulfillment of the generalized Ohm's law) via convective inertia ($m n v_\perp \cdot \nabla v_{||}$). Measurements of strong in-plane electric field structures ($E_\perp \sim $ 1~kV/m) near the X-point reveal a mechanism to efficiently heat ions, as has been recently observed by laser induced fluorescence (LIF) measurements of the ion distribution function[2].\\ \\ This work was supported by a DoE Fusion Energy Sciences Fellowship.\\ \\ $[1]$ J. Egedal, {\it et. al.} (2001), {\it Rev. Sci. Instrum.} 71, 3351 \\ $[2]$ A. Stark, W. Fox, J.Egedal, O. Grulke, T. Klinger, (2005), submitted to Phys. Rev. Lett.