Spectroscopic Measurements of Flow and Ion Temperature at SSX

The Swarthmore Spheromak Experiment (SSX) studies magnetic reconnection by merging co- and counter-helicity spheromaks. Typical plasma parameters include electron density $n_e\sim 10^{15}$ cm$^{-3}$, temperature $T_i+T_e\sim 30$ eV, and magnetic fields $|B|\sim 0.1$ T. We present data from a new ion doppler spectroscopy (IDS) diagnostic. Our IDS system features a 1.33 m Czerny-Turner spectrometer with a 316 grooves/mm echelle grating and a 32-channel photomultiplier tube array. On any shot, we can observe any of 10 different chords through the plasma with submicrosecond time resolution and an instrument temperature $\sim 6$ eV. Current studies have focused on the evolution of the CIII 229.7 nm line which we observe at 25$^{\mathrm{th}}$ order, with dispersion 0.008 mm/nm using magnifying exit optics. Analysis to determine radial and toroidal velocities, as well as ion temperatures, via Abel inversion is underway. Preliminary results suggest near-Alfv\`enic bi-directional flows due to reconnection.