File Download

There are no files associated with this item.

  • Find it @ UNIST can give you direct access to the published full text of this article. (UNISTARs only)
Related Researcher

인용균

In, Yongkyoon
Read More

Views & Downloads

Detailed Information

Cited time in webofscience Cited time in scopus
Metadata Downloads

Investigation of instabilities and rotation alteration in high beta KSTAR plasmas

Author(s)
Park, Y.S.Sabbagh, S.A.Ko, WHBak, J.G.Berkery, J.W.Bialek, J.M.Choi, M.J.Hahn, S.H.In, YongkyoonJardin, S.C.Jeon, Y.M.Kim, J.Kwak, J.G.Lee, S.G.Oh, Y.K.Park, Hyeon KeoYoon, S.W.Yun, G.S.
Issued Date
2017-01
DOI
10.1063/1.4974170
URI
https://scholarworks.unist.ac.kr/handle/201301/21398
Fulltext
http://aip.scitation.org/doi/10.1063/1.4974170
Citation
PHYSICS OF PLASMAS, v.24, pp.012512
Abstract
H-mode plasma operation of the Korea Superconducting Tokamak Advanced Research (KSTAR) device has been expanded to significantly surpass the ideal MHD no-wall beta limit. Plasmas with high normalized beta, βN, up to 4.3 have been achieved with reduced plasma internal inductance, li, to near 0.7, exceeding the computed n = 1 ideal no-wall limit by a factor of 1.6. Pulse lengths at maximum βN were extended to longer pulses by new, more rapid control. The stability of the observed m/n = 2/1 tearing mode that limited the achieved high βN is computed by the M3D-C1 code, and the effect of sheared toroidal rotation to tearing stability is examined. As a method to affect the mode stability in high βN plasmas, the non-resonant alteration of the rotation profile by non-axisymmetric magnetic fields has been used, enabling a study of the underlying neoclassical toroidal viscosity (NTV) physics and stability dependence on rotation. Non-axisymmetric field spectra were applied using in-vessel control coils (IVCCs) with varied n = 2 field configurations to alter the plasma toroidal rotation profile in high beta H-mode plasmas and to analyze their effects on the rotation. The rotation profile was significantly altered with rotation reduced by more than 60% without tearing activity or mode locking. To investigate the physical characteristics and scaling of the measured rotation braking by NTV, changes in the rotation profile are analytically examined in steady state. The expected NTV scaling with the square of the normalized applied field perturbation agrees with the measured profile change δB2.1-2.3. The NTV is also found to scale as Ti 2.1-2.4, in general agreement with the low collisionality 1/ν regime scaling of the NTV theory (TNTV-(1/ν ) Ti 2.5).
Publisher
AMER INST PHYSICS
ISSN
1070-664X
Keyword
TOROIDAL-MOMENTUM DISSIPATIONRESISTIVE MHD MODESVISCOSITYSTABILITYTOKAMAKS

qrcode

Items in Repository are protected by copyright, with all rights reserved, unless otherwise indicated.