Determination of poloidal mode numbers of MHD modes and their radial location 
using a soft x-ray camera array in the Wendelstein 7-X stellarator

Dreval, M. B.; Brandt, C.; Schilling, J.; Thomsen, H.; Beletskii, A.; Könies, A.; W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

doi:10.1088/1361-6587/abf449

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Determination of poloidal mode numbers of MHD modes and their radial location using a soft x-ray camera array in the Wendelstein 7-X stellarator

MPS-Authors

/persons/resource/persons265535

Beletskii, A.
Nano-Systems from Ions, Spins and Electrons, Max Planck Institute of Microstructure Physics, Max Planck Society;

External Resource

https://doi.org/10.1088/1361-6587/abf449
(Publisher version)

https://publikationen.bibliothek.kit.edu/1000133364/151186934
(Preprint)

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

Fulltext (public)

There are no public fulltexts stored in PuRe

Supplementary Material (public)

There is no public supplementary material available

Citation

Dreval, M. B., Brandt, C., Schilling, J., Thomsen, H., Beletskii, A., Könies, A., et al. (2021). Determination of poloidal mode numbers of MHD modes and their radial location using a soft x-ray camera array in the Wendelstein 7-X stellarator. Plasma Physics and Controlled Fusion, 63(6): 065006. doi:10.1088/1361-6587/abf449.

Cite as: https://hdl.handle.net/21.11116/0000-0009-2FAD-1

Abstract

A forward modeling technique is developed for determining the characteristic features of observed MHD modes from the line-of-sight data of the soft x-ray (SXR) tomography diagnostics in the Wendelstein 7-X (W7-X) stellarator. In particular, forward modeling is used to evaluate the poloidal mode numbers m, radial location, poloidal rotation direction and ballooning character of the MHD modes. The poloidal mode structures have been modeled by the radially localized Gaussian-shaped emission regions rotating along the magnetic surfaces. In the present study the cases of rigid-shape emission regions and flexible emission regions are modeled. Various mode phase velocity dependences on the magnetic surface position are simulated. The modeled phase dynamics of line-integrated oscillations and the distribution of oscillation amplitudes are compared with the experimental signals of the SXR cameras which observe the plasma at various viewing angles in the poloidal cross-section. Application of this technique enables describing of the 1–50 kHz modes. In particular, in the discharge W7X-PID 20180918.045 three identified branches with the poloidal mode numbers m= 8, m= 10 and m= 11 localized at ρ ≈ 0.3 are rotating in the clockwise poloidal direction. The present paper reports the first application of the forward modeling technique to the data from the SXR diagnostics in W7-X. The high m-modes are identified by forward modeling in W7-X.