Nonlinear saturation of resistive tearing modes in a cylindrical tokamak with and without solving the dynamics

Abstract

We show that the saturation of resistive tearing modes in a cylindrical tokamak, as well as the corresponding island width, can be directly calculated with an MHD equilibrium code without solving the dynamics and without considering resistivity. The results are compared to initial value resistive MHD simulations and to an analytical nonlinear theory. For small enough islands, the agreement is remarkable. For sufficiently large islands, the equilibrium calculations, which assume a flat current profile inside the island, overestimate the saturation amplitude. On the other hand, excellent agreement between nonlinear resistive MHD simulations and nonlinear theory is observed for all the considered tearing unstable equilibria.

References in corpus (3)

• Rigorous approach to the nonlinear saturation of the tearing mode in cylindrical and slab geometry
• Stepped pressure equilibrium with relaxed flow and applications in reversed-field pinch plasmas
• On the relationship between the multi-region relaxed variational principle and resistive inner layer theory

Cited by in corpus (3)

• Direct prediction of saturated neoclassical tearing modes in slab using an equilibrium approach
• Sawtooth crash in tokamak as a sequence of Multi-region Relaxed MHD equilibria
• Near-ideal relaxed MHD in slab geometry