Non-linear extended MHD simulations of type-I edge localised mode cycles in ASDEX Upgrade and their underlying triggering mechanism

Nuclear Fushion

article

A. Cathey¹  M. Hoelzl¹  K. Lackner¹  G.T.A. Huijsmans³  M.G. Dunne¹  E. Wolfrum¹  S.J.P. Pamela⁵  F. Orain⁶  S. Günter¹ 

[1] Max Planck Institute for Plasma Physics;Physik Department;CEA;Eindhoven University of Technology;CCFE, Culham Science Centre;Centre de Physique Théorique

关键词: ELM simulations;    extended MHD;    magnetic reconnection;    JOREK;    non-linear MHD;   

DOI  :  10.1088/1741-4326/abbc87

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

A triggering mechanism responsible for the explosive onset of edge localised modes (ELMs) in fusion plasmas is identified by performing, for the first time, non-linear magnetohydrodynamic simulations of repetitive type-I ELMs. Briefly prior to the ELM crash, destabilising and stabilising terms are affected at different timescales by an increasingly ergodic magnetic field caused by non-linear interactions between the axisymmetric background plasma and growing non-axisymmetric perturbations. The separation of timescales prompts the explosive, i.e. faster than exponential, growth of an ELM crash which lasts sim!!500~mumathrm{s} . The duration and size of the simulated ELM crashes compare qualitatively well with type-I ELMs in ASDEX Upgrade. As expected for type-I ELMs, a direct proportionality between the heating power in the simulations and the ELM repetition frequency is obtained. The simulations presented here are a major step forward towards predictive modelling of ELMs and of the assessment of mitigation techniques in ITER and other future tokamaks.

【 授权许可】

Unknown