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  4. Demonstration of sawtooth period control with EC waves in KSTAR
 
conference paper

Demonstration of sawtooth period control with EC waves in KSTAR

Jeong, J H
•
Bae, Y S
•
Joung, M
Show more
Kubo, S.
2015
EPJ Web of Conferences
18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating (EC-18)

The sawtooth period control in tokamak is important issue in recent years because the sawtooth crash can trigger TM/NTM instabilities and drive plasmas unstable. The control of sawtooth period by the modification of local current profile near the q=1 surface using ECCD has been demonstrated in a number of tokamaks [1, 2] including KSTAR. As a result, developing techniques to control the sawtooth period as a way of controlling the onset of NTM has been an important area of research in recent years [3]. In 2012 KSTAR plasma campaign, the sawtooth period control is carried out by the different deposition position of EC waves across the q=1 surface. The sawtooth period is shortened by on-axis co-ECCD (destabilization), and the stabilization of the sawtooth is also observed by off-axis co-ECCD at outside q=1 surface. In 2013 KSTAR plasma campaign, the sawtooth locking experiment with periodic forcing of 170 GHz EC wave is carried out to control the sawtooth period. The optimal target position which lengthens the sawtooth period is investigated by performing a scan of EC beam deposition position nearby q=1 surface at the toroidal magnetic field of 2.9 T and plasma current of 0.7 MA. The sawtooth locking by the modulated EC beam is successfully demonstrated as in [3-5] with the scan of modulation-frequency and duty-ratio at the low beta (8N-0.5) plasma. In this paper, the sawteeth behavior by the location of EC beam and the preliminary result of the sawtooth locking experiments in KSTAR will be presented.

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Type
conference paper
DOI
10.1051/epjconf/20158702016
Web of Science ID

WOS:000358327700027

Author(s)
Jeong, J H
Bae, Y S
Joung, M
Kim, D
Goodman, T P
Sauter, O
Sakamoto, K
Kajiwara, K
Oda, Y
Kwak, J G
Show more
Editors
Kubo, S.
Date Issued

2015

Publisher

EDP Sciences

Published in
EPJ Web of Conferences
Volume

87

Start page

02016

Subjects

KSTAR

•

ECH

•

ECCD

•

sawtooth

URL

URL

http://ec18.nifs.ac.jp/

URL

https://crpplocal.epfl.ch/pinboard/papers/143111701.pdf
Editorial or Peer reviewed

REVIEWED

Written at

OTHER

EPFL units
CRPP  
SPC  
Event nameEvent placeEvent date
18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating (EC-18)

Nara, Japan

22-25 April 2014

Available on Infoscience
March 25, 2015
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/112740
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