Helium Ion Temperatures During Magnetic Reconnection in PHASMA

Recently, the PHASMA experiment has begun studies of magnetic reconnection in helium plasmas. Compared to argon, the smaller gyro-radius of helium allows the ions to begin to participate in the reconnection physics. However, the velocity distribution function of helium ions is not easily measured with laser induced fluorescence. To obtain a line-averaged (along the viewing chord) measurement of the helium ion temperature during reconnection, we used a custom-built .5 pm resolution LightMachinery spectrometer. The linewidth of helium ion lines is then measured as a function of time during a strong guide field magnetic reconnection study in PHASMA. Preliminary measurements using a lower resolution, 1.3 m focal length, McPherson spectrometer will also be presented.