Analysis of coupled MHD modes with Mirnov probes in ASDEX Upgrade
With the help of a simulation of the perturbation field and a comparison with Mirnov measurements, it becomes possible to investigate coupled magnetohydrodynamic (MHD) modes. The structure and the width of the different coupled islands can be estimated. For a reliable simulation, it is necessary to take into account the induced screening currents in the vessel wall and in some of the in-vessel components. The fields of these screening currents have a large influence on the measurements. This improved analysis method is demonstrated for the development of coupled modes during a density limit disruption. It is clearly shown that an increase of the coupled islands leads to minor disruptions. Owing to mode locking, reliable results are not possible before major disruptions.
Bibliographic Reference: Article: Nuclear Fusion, Vol. 37 (1997) No. 9, pp. 1255-1270
Record Number: 199711620 / Last updated on: 1997-12-09
Original language: en
Available languages: en