Ion Temperature Measurements during Multiscale Reconnection on the FLARE Device

Magnetic reconnection is known to be one of the most efficient processes for converting magnetic energy in a plasma system into the kinetic energy of particles. Both electrons and ions are heated during the process, and ion heating can often produce highly energetic ions whose velocities exceed the reconnection-driven Alfvén velocity. There are various models proposed to explain ion acceleration, depending on specific spatial scales and parameter regimes, but no systematic experimental scan has verified the dominant ion-heating mechanism in a system that simultaneously accesses small-and large-scale physics, which is necessary for inherently multiscale reconnection. Here, we present preliminary experimental work to measure ion temperature and analyze ion-heating mechanism in the multiscale laboratory reconnection device, the Facility for Laboratory Reconnection Experiments (FLARE) [1]. FLARE is designed to provide experimental access to various multiscale reconnection regimes, including multiple X-line reconnection. Using a multichannel, 1D ion Doppler spectroscopy system, we plan to measure ion temperature and flow velocity during the reconnection process. The diagnostic setup, calibration, and data-processing methods are discussed.

[1] H. Ji, W. Daughton, J. Jara-Almonte, A. Le, A. Stanier, J. Yoo, Nature Reviews Physics 4, 263 (2022).