Mass dependent ion heating in the SSX reconnection device

Ion heating due to magnetic reconnection is measured in the SSX plasma merging device for a variety of ion masses and charge states with a high resolution ion Doppler spectrometer. The SSX IDS instrument measures the width and Doppler shift of the nascent $C_{III}$ impurity $229.7~nm$ line, a doped $He_{II}$ impurity $468.6~nm$ line, or a doped $Ar_{II}$ impurity line to determine the temperature and line-averaged flow velocity. The velocity resolution of the instrument is $\le 5~km/s$. There is enough signal to resolve the full line within an MHD dynamical time (about $1~\mu s$ in SSX). Peak ion temperatures of $80~eV$ have been recorded during reconnection events as well as flows up to $40~km/s$. Spheromak merging in a new slightly prolate flux conserver ($R=0.2~m, L=0.4~m$) often results in excitation of several unstable MHD modes. After reconnection and instability, we measure a period of reconnection driven ion heating with peak temperatures for carbon $T_C \cong 50~eV$ and for helium $T_{He} \cong 70~eV$ (averaged over many shots). During the decay phase, we observe rapid ion cooling likely due to energetic ion loss. Results from a new ion energy analyzer and Mach probe will be presented.