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 gyroradius 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 have

mounted a gated Andor camera on a 1.3 m double pass 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.