Application of 3D Equilibrium Code to Calculation of Neoclassical Tearing Modes

We have implemented a JFNK (Jacobian-free Newton-Krylov) method in PIES (the Princeton Iterative Equilibrium Solver), which solves for 3D MHD equilibria. The code uses numerous enhancements to traditional JFNK, including adaptive preconditioning and subspace restricted Levenberg-Marquardt backtracking. The code has also been modified to handle neoclassical effects and is being validated against neoclassical tearing mode data from the TFTR tokamak.