Marc Maraschek

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First experiments with nonaxisymmetric magnetic perturbations, toroidal mode number n=2, produced by newly installed in-vessel saddle coils in the ASDEX Upgrade tokamak show significant reduction of plasma energy loss and peak divertor power load associated with type-I edge localized modes (ELMs) in high-confinement mode plasmas. ELM mitigation is observed(More)
A radially movable probe has been developed for studies of filamentary transport in ASDEX Upgrade during edge localized modes (ELMs) by means of Langmuir tips and magnetic pickup coils. The probe is permanently installed at the low field side in the ASDEX Upgrade vacuum vessel and is not subject to limitations in probe size, as, for example, probes on a(More)
We present here the first phase-space characterization of convective and diffusive energetic particle losses induced by shear Alfvén waves in a magnetically confined fusion plasma. While single toroidal Alfvén eigenmodes (TAE) and Alfvén cascades (AC) eject resonant fast ions in a convective process, an overlapping of AC and TAE spatial structures leads to(More)
Time-resolved energy and pitch angle measurements of fast-ion losses correlated in frequency and phase with high-frequency magnetohydrodynamic perturbations have been obtained for the first time in a magnetic fusion device and are presented here. A detailed analysis of fast-ion losses due to toroidal Alfvén eigenmodes has revealed the existence of a new(More)
The efficiency of generating a helical current in magnetic islands for the purpose of suppression of neoclassical tearing modes (NTMs) by electron cyclotron current drive (ECCD) is studied experimentally in the ASDEX Upgrade tokamak. It is found that the efficiency of generating helical current by continuous current drive in a rotating island drops(More)
Measurements at different experiments have shown that a few 10% of the energy loss from the confined plasma during an ELM cycle is deposited to non-divertor components. Usually, these components are not designed to receive high heat loads. The measurement and the extrapolation of these non-divertor loads to a next step fusion reactor are essential for the(More)
P. Manz, G. Birkenmeier, G. Fuchert, M. Cavedon, G.D. Conway, M. Maraschek, A. Medvedeva F. Mink, B.D. Scott, L.M. Shao, U. Stroth and the ASDEX Upgrade Team 1 Physik-Department E28, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany 2 Max-Planck-Institut für Plasmaphysik, Boltzmannstr.2 ,85748 Garching, Germany 3 Institute of(More)
Codrina Ionita, Nicola Vianello, Hans W. Müller, Franz Mehlmann, Matteo Zuin, Volker Naulin, Jens J. Rasmussen, Volker Rohde, Roberto Cavazzana, Catalin Lupu, Marc Maraschek, Roman W. Schrittwieser, Petru C. Balan, ASDEX Upgrade Team Association EURATOM/ÖAW, Institute for Ion Physics and Applied Physics, University of Innsbruck, Austria Association(More)
Magnetically confined plasmas in the high confinement regime are regularly subjected to relaxation oscillations, termed edge localized modes (ELMs), leading to large transport events. Present ELM theories rely on a combined effect of edge current and the edge pressure gradients which result in intermediate mode number (n≅10-15) structures (filaments)(More)
Long period sawteeth have been observed to result in the low-β triggering of neo-classical tearing modes (NTMs), which can significantly degrade plasma confinement. In ITER, the stabilising effects of the fusion-born α particles are likely to exacerbate this. Consequently, it is important to develop a detailed physical understanding of sawtooth behaviour.(More)