Adaptive Mesh Refinement for MHD Fusion Applications

Abstract

We present results from adaptive mesh refinement (AMR) simulations of two MHD applications relevant to magnetic fusion. The applications are: pellet injection in tokamaks (PI) and magnetic reconnection (MR). For PI, AMR is essential to provide the resolution required to simulate realistic pellet sizes relative to device dimensions (typical ratios are O(10-3)). We present results from 3D AMR simulations in a tokamak geometry with emphasis on differences between the low-field and high-field side pellet launches. For MR, We present results from 2D AMR simulations in which both the outer “inviscid” region and the inner “resistive” region are well-resolved. AMR provides an efficient means of resolving the near-singular current sheets in the inner region where the actual breaking and reconnection of the magnetic field lines takes place. The numerical method developed is an explicit unsplit upwinding treatment of the 8-wave formulation, coupled with a MAC projection method to enforce the solenoidal property of the magnetic field. The Chombo framework is used for AMR.