Device overview and first results from the gas dynamic trap prototype*

A new GDT inspired mirror experiment is under development at the University of Wisconsin at Madison for possible application as a beam driven neutron source. The gas dynamic trap (GDT) has shown remarkable results in recent years, with major improvements in electron thermal confinement and plasma stability at high beta. UW-Madison is in a conceptual design phase for a GDT experiment for fusion research, basic plasma physics studies and as a cost-effective neutron source. Envisioned neutron production rates range from 10¹⁵ to 10¹⁸ neutrons/sec. As a first development step our prototype uses 6 T HTS REBCO end mirror coils, developed in collaboration with GA, resulting in a mirror ratio of 20. The plasma is sustained using a helicon wave with a steady state power of 10 kW. Physics goals include demonstration of MHD-stability in quasi-stationary conditions, suitable for NBI absorption (0.7 MW, 20 kV, 50 ms NBI into n_e ~ 5 x 10¹⁹ m^-3, T_e ~ 200 eV plasma), electron temperature control, plasma rotation and biasing with LaB₆ cathodes, NBI fueling and Li end wall pumping as well as understanding electron thermal confinement in the collisionless expander and the helicon dispersion relation in strong magnetic fields. First results will be presented.