Second Generation Magnetic Flux Array for the Terrestrial Reconnection Experiment (TREX)

TREX, part of the Wisconsin Plasma Astrophysics Laboratory, studies magnetic reconnection in a variety of regimes. In its prior configuration, TREX used two coils inside a 3m spherical vacuum vessel filled with plasma to create a magnetic field opposing a background field from an external Helmholtz coil, driving reconnection. In order to study the reconnection process, we first constructed a 160 channel Magnetic Flux Array, which allowed us to infer the flux function, $\Psi $, and thus the toroidal component of the vector potential, \textbf{A}$\phi $, as a function of time over the array area. From \textbf{A}$\phi $, we further found the field geometry, current density, and reconnection rate [1]. Following the success of this array [2], a second array was constructed with similar parameters but with the addition of a thin stainless steel shield to reduce noise and a set of toroidal field Bdot coils. Data from this second array in the most recent run of TREX will be presented and compared to the results from the first array. [1] Kesich et al., Review of Scientific Instruments 79,063505 (2008). [2] Olson et al., PRL (2016)