Overview of C-2U FRC Experimental Program and Plans for C-2W

Tri Alpha Energy's experimental program has been focused on a demonstration of reliable field-reversed configuration (FRC) formation and sustainment, driven by fast ions via high-power neutral-beam (NB) injection. The world's largest compact-toroid experimental devices, C-2 [1] and C-2U [2], have successfully produced a well-stabilized, sustainable FRC plasma state with NB injection (input power, P$_{\mathrm{NB}}$ \textasciitilde 10$+$ MW; 15 keV hydrogen) and end-on coaxial plasma guns. Remarkable improvements in confinement and stability of FRC plasmas have led to further improved fast-ion build up; thereby, an advanced beam-driven FRC state has been produced and sustained for up to 5$+$ ms (longer than all characteristic system time scales), only limited by hardware and electric supply constraints such as NB and plasma-gun power supplies. To further improve the FRC performance the C-2U device is being replaced by C-2W featuring higher injected NB power, longer pulse duration as well as enhanced edge-biasing systems and substantially upgraded divertors. Main C-2U experimental results and key features of C-2W will be presented. \newline \newline [1] M.W. Binderbauer \textit{et al.}, Phys. Plasmas \textbf{22}, 056110 (2015). \newline [2] M.W. Binderbauer \textit{et al.}, AIP Conference Proceedings \textbf{1721}, 030003 (2016).