Increasing performance of the FRCHX plasma injector system

Summary form only given. The Field-Reversed Configuration Heating Experiment (FRCHX) is an experiment developed in collaboration between the Air Force Research Laboratory (AFRL) and Los Alamos National Laboratory (LANL) to form compact (r
_s
= 2.5~3.5 cm), high density (n
_e
= 3~4×10
¹⁶
cm
^-3
) field-reversed configuration (FRC) plasmas intended for subsequent adiabatic compression to high energy density conditions. The FRC plasma is first formed via reversed-field theta pinch in a Deuterium background plasma. The theta coil which forms the FRC is conical to impart sufficient momentum to the plasma to translate it a short distance, where it is trapped by a magnetic well within a cylindrical flux-conserving aluminum solid liner. Once trapped, the FRC is diagnosed and/or compressed by the magnetically-driven implosion of the liner. The lifetime of the FRC's poloidal flux is an important parameter affecting plasma confinement during compression and ultimately its peak density, temperature, and neutron yield. Despite substantial improvements in lifetime recently achieved (14~16 μs now versus 7~9 μs previously1), a significantly longer lifetime (at least 2×) is still needed. We are therefore proposing to demonstrate substantially improved plasma target formation by merging two counterpropagating FRC plasmas within a central trapping/compression region. Trapped poloidal flux lifetimes 2 to 3 times longer with densities exceeding 1×1017 cm-3, temperatures (Te+Ti) exceeding 500 eV, and 4-5 T embedded magnetic fields are projected. These parameters surpass any achieved previously with uncompressed FRC plasmas. A discussion of the first FRCHX plasma formation system will be presented along with a description of the diagnostics used to diagnose the trapped FRC. The FRC parameters that were ultimately achieved with this system will also be provided. The presentation will conclude with an overview of the proposed FRC merging system and further details of the projected uncompressed FRC parameters anticipated with this new system.