Ion heating due to reconnection and turbulence in SSX

Ion heating is measured in the SSX device with a high resolution ion Doppler spectrometer. The SSX IDS instrument measures the width and Doppler shift of either the nascent $C_{III}$ impurity $229.7~nm$ line or a doped $He_{II}$ impurity $468.6~nm$ 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). Spheromak merging in a new oblate flux conserver ($R=0.25~m, L=0.4~m$) has resulted in some stable configurations but often results in excitation of several unstable MHD modes. After reconnection and instability, we measure a period of ion heating with peak temperatures for carbon $T_C = 40~eV$ but for helium only $T_{He} = 20~eV$. Our results are consistent with temperature increasing with ion mass but only scaling like $\sqrt{M_i/m_p}$. We plan a more comprehensive study of the effect of reconnection and turbulence on ion heating for various ion masses (He, C, Xe). A new high purity gas delivery and mixing system is under construction. Results of ion heating with other ions will be presented.