Experimental tests of linear and nonlinear three-dimensional equilibrium models in DIII-D

摘要: DIII-D experiments using new detailed magnetic diagnostics show that linear, ideal magnetohydrodynamics (MHD) theory quantitatively describes the structure (as measured externally) of three-dimensional (3D) equilibria resulting from applied fields with toroidal mode number n = 1, while a nonlinear solution to MHD force balance, VMEC code, requires inclusion ≥ 1 achieve similar agreement. These tests are carried out near ITER baseline parameters, providing validated basis on which exploit 3D for plasma control development. Scans poloidal spectrum and edge safety factor confirm low-pressure, non-axisymmetric tokamak determined by single, dominant, stable eigenmode. However, at higher beta, kink stability limit in absence conducting wall, qualitative features observed vary way is not captured MHD.