PHY3915 IFS Seminar with Max Ruth

Stellarator equilibria can develop current sheets at surfaces of resonant rotational transform. Such currents violate the length-scale assumptions of MHD and lead to non- or slow convergence of numerical methods under refinement. In this talk, we will show how the introduction of magnetic fluctuations in the MHD variational principle results in a magnetic Reynolds stress. By including more physics, this stress improves the conditioning of the equilibrium problem, leading to convergent numerical methods. We demonstrate this through a numerical solver for the equilibrium problem with convergent force-balance.

Max Ruth is a postdoctoral researcher at the Institute for Fusion Studies at the University of Texas at Austin. He obtained his PhD from Cornell University in Applied Mathematics. He is broadly interested in interplay between plasmas, Hamiltonian dynamical systems, and numerical methods.