MHD Equilibrium Analysis with Anisotropic Pressure in LHD

Abstract

The effects of anisotropic pressure on MHD equilibrium are investigated, particularly focused on the position of the magnetic axis. MHD equilibria are numerically calculated under anisotropic pressure conditions using an extension of the VMEC code which is widely applied to obtain three dimensional MHD equilibria. This code is called ANIMEC. A bi-Maxwellian model was invoked in this code in order to treat anisotropic pressure driven by energetic particles without any inconsistency. To investigate the properties of the plasma with p_∥ > p_⊥, numerical computations under various conditions are performed with a LHD magnetic configuration using the ANIMEC code. Comparisons of the plasma behavior between an analytical model that considers p_∥ and p_⊥ to be constant on each flux surface and ANIMEC numerical results will be discussed.