MUSE: A Simple Optimized Stellarator Using Permanent Magnets

A simple, inexpensive quasi-axisymmetric optimized stellarator ‘MUSE’ is being constructed using rare-earth permanent magnets to generate the 3D magnetic field structure combined with simple planar coils to generate the toroidal magnetic flux. Advanced manufacturing is being used to precisely fabricate the magnet support structures, simplifying metrology and the assembly process. High precision magnets are readily available commercially.  The stellarator equilibrium is highly optimized for good neoclassical confinement with $\epsilon_{eff}^{3/2}$, the coefficient characterizing 3D neoclassical transport calculated to be significantly lower than in any previous stellarator. The experiment is designed to be table-top scale with $R = 0.30$ m and $B = 0.15$ T, suitable for basic physics experiments. The design approach, construction status, and plans will be discussed.