이정표
2019-11-25T04:46:55Z
2019-11-25T04:46:55Z
2017-05
NUCLEAR FUSION, v. 57, no. 6, Article no. 066051
0029-5515
1741-4326
https://iopscience.iop.org/article/10.1088/1741-4326/aa6877
https://repository.hanyang.ac.kr/handle/20.500.11754/114075
A highly elongated plasma is desirable in order to increase plasma pressure and energy confinement to maximize fusion power output. However, there is a limit to the maximum achievable elongation which is set by vertical instabilities driven by the n = 0 MHD mode. This limit can be increased by optimizing several parameters characterizing the plasma and the wall. The purpose of our study is to explore how and to what extent this can be done. Specifically, we extend many earlier calculations of the n = 0 mode and numerically determine scaling relations for the maximum elongation as a function of dimensionless parameters describing (1) the plasma profile (beta(p) and l(i)), (2) the plasma shape (epsilon and delta), (3) the wall radius (b/a) and (4) most importantly the feedback system capability parameter gamma T-w. These numerical calculations rely on a new formulation of n = 0 MHD theory we recently developed (Freidberg et al 2015 J. Plasma Phys. 81 515810607, Lee et al 2015 J. Plasma Phys. 81 515810608) that reduces the 2D stability problem into a 1D problem. This method includes all the physics of the ideal MHD axisymmetric instability while reducing the computation time significantly, so that many parameters can be explored during the optimization process. The scaling relations we present include the effects of the optimal triangularity and the finite aspect ratio on the maximum elongation, and can be useful for determining optimized plasma shapes in current experiments and future tokamak designs.
The authors would like to thank Professor Dennis Whyte (MIT) for providing the motivation for this work and for many insightful conversations. J. L. and J. F. were supported by the U.S. Department of Energy, Office of Science, Fusion Energy Sciences under Award Number DE-FG02-91ER54109. A. C. was supported by the U.S. Department of Energy, Office of Science, Fusion Energy Sciences under Award Numbers. DE-FG02-86ER53223 and DE-SC0012398. M. G. was supported by the U.S. Department of Energy, Office of Science, Fusion Energy Sciences under Award Numbers. DE-FC02-99ER54512.
en_US
IOP PUBLISHING LTD
tokamak equilibrium
MHD resistive wall mode
vertical elongation
An analytic scaling relation for the maximum tokamak elongation against n=0 MHD resistive wall modes
Article
6
57
10.1088/1741-4326/aa6877
66051-66059
NUCLEAR FUSION
Lee, Jungpyo
Freidberg, Jeffrey
Cerfon, Antoine
Greenwald, Martin
2017003730
S
COLLEGE OF ENGINEERING[S]
DEPARTMENT OF NUCLEAR ENGINEERING
jungpyo
E-4796-2018
http://orcid.org/0000-0002-4382-4515