NIMROD Modeling of the Compact Toroidal Hybrid (CTH)

The 3D extended MHD code NIMROD [1] has been modified to model the non-axisymmetric vacuum fields of the Compact Toroidal Hybrid (CTH) torsatron. Previous results [2] have shown good agreement between modeled and experimental vacuum fields as well as the formation and growth of island structures in discharges with driven current at zero $\beta$ and constant conductivity. Modeling of current-driven discharges with self consistent Ohmic heating and finite $\beta$ will be presented. A new post-processor to calculate the expected signals from experimental diagnostics using NIMROD simulation data is under development. Preliminary comparisons using magnetic diagnostic data from CTH will be shown. \\[4pt] [1] C.R. Sovinec, A.H. Glasser, D.C. Barnes, T.A. Gianakon, R.A. Nebel, S.E. Kruger, D.D. Schnack, S.J. Plimpton, A. Tarditi, M.S. Chu and the NIMROD Team, ``Nonlinear Magnetohydrodynamics with High-order Finite Elements,'' Journal of Computational Physics, 195, 355 (2004).\\[0pt] [2] M. G. Schlutt et al, submitted to Nucl. Fusion (2012)