In February 2019, the Big Red Ball (BRB) was operated for an initial investigation of compact toroid (CT) collisions as proposed by a Los Alamos National Laboratory (LANL) group. LANL researchers Scott Hsu and Tom Byvank visited WiPPL to work with UW-Madison physics graduate student Doug Endrizzi on these experiments. A chief motivation for the work was a hypothetical plasma state described by Dmitri Ryutov [Fusion Science and Technology 56, 1489 (2009)] wherein the normalized thermal pressure is high (beta>1) yet the plasma is magnetized (wt>1) by a tangled field. Such a state might be of interest as a compression target for magnetized target fusion or as a laboratory setting with connections to astrophysical molecular clouds.
Byvank and Endrizzi operated BRB in order to inject and collide two CT plasmas, diagnosing their speed, magnetic structure, and kinetic properties with moveable arrays of internal probes. Each CT plasma was formed and injected with one of two CT injectors at WiPPL, one on loan from TAE Technologies, Inc., the other designed by Endrizzi based on the TAE design and built by WiPPL. The video below shows an example of the collision process, with the two CT plasmas colliding together in the core region of BRB where the diagnostic probe arrays are visible. The results of these initial experiments are promising, and further collaborations are being planned.