Overview of recent results and future plans in the Lithium Tokamak Experiment-β

The Lithium Tokamak Experiment-β has achieved several key prerequisites and advanced the understanding of the plasma physics, surface science, and technology for a fusion device operating with low recycling, lithium, and/or liquid metal surfaces. Low recycling coefficients have been measured along with flat T_e profiles, and the regime has been documented and sustained with higher levels of plasma performance, NBI heating, and liquid Li walls. New experiments with visibly shiny liquid Li coatings have reproduced and expanded on some of the solid Li results and can also be compared to experiments with strongly degraded Li.

Following five years of continuous operation without a vacuum vent, the Lithium Tokamak Experiment-β is now in a brief outage period. The main focus will be to re-aim the neutral beam to a higher tangency radius in order to reduce first orbit losses and enable coupling at higher beam energy. ECRH startup and operational improvements to the beam, Li evaporators, and gas fueling systems are also planned. Plans for new diagnostics include a neutral particle analyzer, while plans for improved diagnostics include beam calorimetry and Thomson scattering. Future research will further study the unique low recycling and liquid Li regimes with even higher plasma performance, dominant NBI heating, and improved control over recycling and neutral fueling.