TY - JOUR
T1 - ELM-induced cold pulse propagation in ASDEX Upgrade
JF - Plasma Physics and Controlled Fusion
Y1 - 2019
A1 - Trier, E.
A1 - Wolfrum, E.
A1 - Willensdorfer, M.
A1 - Yu, Q.
A1 - Hoelzl, M.
A1 - Orain, F.
A1 - Ryter, F.
A1 - Angioni, C.
A1 - Bernert, M.
A1 - Vanovac, B.
A1 - Dunne, M. G.
A1 - Denk, S. S.
A1 - Fuchs, J. C.
A1 - Fischer, R.
A1 - Hennequin, P.
A1 - Kurzan, B.
A1 - Mink, F.
A1 - Mlynek, A.
A1 - Odstrcil, T.
A1 - Schneider, P. A.
A1 - Stroth, U.
A1 - Tardini, G.
A1 - ASDEX Upgrade Team
A1 - EUROfusion MST1 Team
AB - In ASDEX Upgrade, the propagation of cold pulses induced by type-I edge localized modes (ELMs) is studied using electron cyclotron emission measurements, in a dataset of plasmas with moderate triangularity. It is found that the edge safety factor or the plasma current are the main determining parameters for the inward penetration of the T e perturbations. With increasing plasma current the ELM penetration is more shallow in spite of the stronger ELMs. Estimates of the heat pulse diffusivity show that the corresponding transport is too large to be representative of the inter-ELM phase. Ergodization of the plasma edge during ELMs is a possible explanation for the observed properties of the cold pulse propagation, which is qualitatively consistent with non-linear magneto-hydro-dynamic simulations.
VL - 61
IS - 4
U1 - FP
U2 - TP
U5 - 0279758ced9029d70a2148b4f3b6cd99
ER -
TY - JOUR
T1 - Insights into type‐I edge localized modes and edge localized mode control from JOREK non‐linear magneto‐hydrodynamic simulations
JF - Contributions to Plasma Physics
Y1 - 2018
A1 - Hoelzl, M.
A1 - Huijsmans, G. T. A.
A1 - Orain, F.
A1 - Artola, F. J.
A1 - Pamela, S.
A1 - Becoulet, M.
A1 - van Vugt, D.
A1 - Liu, F.
A1 - Futatani, S.
A1 - Vanovac, B.
A1 - Lessig, A.
A1 - Wolfrum, E.
A1 - Mink, F.
A1 - Trier, E.
A1 - Dunne, M.
A1 - Viezzer, E.
A1 - Eich, T.
A1 - Frassinetti, L.
A1 - Gunter, S.
A1 - Lackner, K.
A1 - Krebs, I.
A1 - ASDEX Upgrade Team
A1 - EUROfusion MST1 Team
KW - ballooning mode
KW - ELM control
KW - ELMs
KW - JOREK
KW - MHD
KW - mode coupling
KW - stochastic field
KW - TOKAMAK
AB - Edge localized modes (ELMs) are repetitive instabilities driven by the large pressure gradients and current densities in the edge of H‐mode plasmas. Type‐I ELMs lead to a fast collapse of the H‐mode pedestal within several hundred microseconds to a few milliseconds. Localized transient heat fluxes to divertor targets are expected to exceed tolerable limits for ITER, requiring advanced insights into ELM physics and applicable mitigation methods. This paper describes how non‐linear magneto‐hydrodynamic (MHD) simulations can contribute to this effort. The JOREK code is introduced, which allows the study of large‐scale plasma instabilities in tokamak X‐point plasmas covering the main plasma, the scrape‐off layer, and the divertor region with its finite element grid. We review key physics relevant for type‐I ELMs and show to what extent JOREK simulations agree with experiments and help reveal the underlying mechanisms. Simulations and experimental findings are compared in many respects for type‐I ELMs in ASDEX Upgrade. The role of plasma flows and non‐linear mode coupling for the spatial and temporal structure of ELMs is emphasized, and the loss mechanisms are discussed. An overview of recent ELM‐related research using JOREK is given, including ELM crashes, ELM‐free regimes, ELM pacing by pellets and magnetic kicks, and mitigation or suppression by resonant magnetic perturbation coils (RMPs). Simulations of ELMs and ELM control methods agree in many respects with experimental observations from various tokamak experiments. On this basis, predictive simulations become more and more feasible. A brief outlook is given, showing the main priorities for further research in the field of ELM physics and further developments necessary.
VL - 58
IS - 6-8
U1 - FP
U2 - IMT
U5 - 71b9a6aa52e8f79ba2ebd4ec998f6c83
ER -