The Road Towards Measuring Fermi Heating and an Investigation of a Magnetopause of order d_i

Coulomb collisions effectively relax plasma velocity distribution function to a near-Maxwellian form and often hamper the relevance of laboratory experiments to tenuous and near-collisionless space plasma. To overcome this challenge, the Terrestrial Reconnection Experiment (TREX) [J.Olson et al, 2016] at the Wisconsin Plasma Physics Laboratory (WiPPL) [C. B. Forest et al., 2015] is specially designed to be relevant to reconnection in the Earth’s magnetosphere. The experiment deploys an optimized reconnection drive circuit with the ability to drive the electron fluid through the reconnection region faster than the Coulomb collision time of t_ei=10^-6 s [P. Gradney et al., 2023]. The achieved low collisional regime is characterized by Lundquist numbers on the order of S = 10⁵, and the configuration permits multiple magnetic islands to be induced within a reconnection current layer, allowing the dynamics of coalescing islands to be examined. The aim of these experiments is to explore electron heating and energization due to island coalescing. In addition, TREX is also investigating magnetic reconnection in a miniature magnetopause with a size on the order of a few ion skin depths. This is accomplished by placing an electromagnetic dipole in the exhaust region of a TREX magnetic reconnection event. Utilizing arrays of magnetic and electrostatic diagnostics in multiple reproducible plasma discharges, the 3D dynamics associated with the topological rearrangement of the magnetic field is currently being studied.