Beta-Value Limits and MHD 2.Increase in Beta Limit in Tokamak Plasmas

Theoretical studies of equilibrium beta limit in heliotron plasmas

In this study, the MHD equilibrium limit of LHD plasmas is studied using a 3D MHD equilibrium calculation code, HINT2, which is an initial value solver based on the relaxation method without the assumption of nested flux surfaces. For finite beta equilibria, flux surfaces become stochastic in the peripheral region. However, though the axis shifts until the conventional limit, the separatrix to ...

Drift-MHD model of error-field penetration in tokamak plasmas

Nonlinear simulations of macro-instabilities in tokamak plasmas beyond MHD

The simulation of the interaction between macroscopic Alfvén modes and a population of hot ions is one of the challenges in tokamak plasma physics, mainly because of its possible negative impact on the plasma confinement in a future fusion device. The bi-fluid XTOR-2F code [1], using a fully implicit method with an iterative pre-conditioned Newton-Krylov for its solution at every time step has ...

Nonlinear MHD Simulations of Spherical Tokamak and Helical Plasmas

Nonlinear magnetohydrodynamic (MHD) simulations on relaxation phenomena in a spherical tokamak and a helical plasma, including three-dimensional (3D) equilibrium computations, are executed in full toroidal geometries. For a spherical tokamak, two-step evolution of the medium-n ballooning instabilities and a successive excitation of an internal n=1 crash has been observed. A similar process has ...

Scientific workflows for MHD stability chain analysis of tokamak plasmas

R. Coelho , A. Merle , G. Vlad , D. Yadikin , M. Owsiak, O. Sauter , I. Chapman , M. Dunne , P. Buratti [3] and JET contributors and ASDEX Upgrade Team and the EU-IM Team EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK [1] Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal [2] École Polytechnique Fédérale...