Experimental Study of Ion Heating and Acceleration during Magnetic Reconnection
Authors: S.C. Hsu, T.A. Carter, G. Fiksel, H. Ji, R.M. Kulsrud, and M. Yamada
Date of PPPL Report: October 2000
Published in: Phys. Plasmas 8 (May 2001) 1916-1928.
Ion heating and acceleration has been studied in the well-characterized reconnection layer of the Magnetic Reconnection Experiment [M. Yamada et al., Phys. Plasmas 4, 1936 (1997)]. Ion temperature in the layer rises substantially during null-helicity reconnection in which reconnecting field lines are anti-parallel. The plasma out flow is sub-Alfvénic due to a downstream back pressure. An ion energy balance calculation based on the data and including classical viscous heating indicates that the ions are heated largely due to nonclassical mechanisms. The ion temperature rise is much smaller during co-helicity reconnection in which field lines reconnect obliquely. This is consistent with a slower reconnection rate and a smaller resistivity enhancement over the Spitzer value. These observations indicate strongly that nonclassical dissipation mechanisms can play an important role both in heating the ions and in facilitating the reconnection process.