\textsc{Urania:} A Spherical Tokamak for Developing Non-Solenoidal Plasma Startup Techniques

Development of a routine non-solenoidal startup technique is a critical issue facing the spherical tokamak. A major upgrade to the \textsc{Pegasus }program is underway to develop and compare leading non-solenoidal startup techniques on a dedicated solenoid-free facility---the Unified Reduced $A$ Non-Inductive Assessment (\textsc{Urania}) experiment. Facility upgrades for \textsc{Urania} include: increased $B_{T} $ to 0.6 T, extended pulse duration ($\le 100$ ms), an enhanced poloidal field set for improved shape control, and an expanded diagnostic suite, while retaining an ultra-low aspect ratio ($A\approx 1.2)$. Modelling and experiments have informed the design of a new local helicity injection (LHI) system capable of $I_{p} \le 0.3$ MA by leveraging the enhanced $B_{T} $ to increase the Taylor limit early in the discharge. The new LHI system is designed to optimize helicity input and increase Taylor limit via a non-circular current source geometry. A prototype of this new source is in fabrication for testing on \textsc{Pegasus}. A novel system capable of transient and sustained coaxial helicity injection is in design. A modest power (200--400 kW) electron Bernstein wave radiofrequency heating and current drive system will be deployed.