No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The full text of this article is not currently available.
Simulations of sawtoothing in a current carrying stellarator
B. B. Kadomtsev, “ Disruptive instability in tokamaks,” Sov. J. Plasma Phys. 1, 389–391 (1975).
G. A. Müller, V. Erckmann, H. J. Hartfuß, H. Laqua, H. Maassberg, M. Rome, U. Stroth, A. Weller, W VII-AS Team, and ECRH group, “ Shear modification by ECCD and related confinement phenomena in W7-AS,” AIP Conf. Proc. 355, 133 (1996).
S. E. Grebenshchikov, B. I. Kornev, and I. S. Shpigel', “ Soft x-ray sawtooth oscillations in the L-2 stellarator,” Sov. J. Plasma Phys. 8(3), 256–260 (1982).
J. D. Hanson, S. F. Knowlton, B. A. Stevenson, and G. J. Hartwell, “ Equilibrium and stability of current-carrying discharges in the non-axisymmetric CTH experiment,” Contrib. Plasma Phys. 50(8), 724–730 (2010).
M. D. Pandya, M. C. ArchMiller, M. R. Cianciosa, D. A. Ennis, J. D. Hanson, G. J. Hartwell, J. D. Hebert, J. L. Herfindal, S. F. Knowlton, X. Ma, S. Massidda, D. A. Maurer, N. A. Roberds, and P. J. Traverso, “ Low edge safety factor operation and passive disruption avoidance in current carrying plasmas by the addition of stellarator rotational transform,” Phys. Plasmas 22(11), 110702 (2015).
M. C. ArchMiller, M. R. Cianciosa, D. A. Ennis, J. D. Hanson, G. J. Hartwell, J. D. Hebert, J. L. Herfindal, S. F. Knowlton, X. Ma, D. A. Maurer et al., “ Suppression of vertical instability in elongated current-carrying plasmas by applying stellarator rotational transform,” Phys. Plasmas 21(5), 056113 (2014).
H. Reimerdes, A. Pochelon, O. Sauter, T. P. Goodman, M. A. Henderson, and An. Martynov, “ Effect of triangularity and elongated plasma shape on the sawtooth stability,” Plasma Phys. Controlled Fusion 42(6), 629–639 (2000).
A. Pochelon, F. Hofmann, H. Reimerdes, C. Angioni, R. Behn, R. Duquerroy, I. Furno, P. Gomez, T. P. Goodman, M. A. Henderson, An. Martynov, P. Nikkola, O. Sauter, and A. Sushkov, “ Plasma shape effects on sawtooth/internal kink stability and plasma shaping using electron cyclotron wave current profile tailoring in TCV,” Nucl. Fusion 41(11), 1663–1669 (2001).
E. A. Lazarus, F. L. Waelbroeck, T. C. Luce, M. E. Austin, K. H. Burrell, J. R. Ferron, A. W. Hyatt, T. H. Osborne, M. S. Chu, D. P. Brennan et al., “ A comparison of sawtooth oscillations in bean and oval shaped plasmas,” Plasma Phys. Controlled Fusion 48(8), L65–L72 (2006).
M. Wakatani, H. Shirai, H. Zushi, H. Kaneko, O. Motojima, T. Obiki, A. Iiyoshi, and K. Uo, “ Numerical studies of internal disruptions in Heliotron E,” Nucl. Fusion 23(12), 1669 (1983).
R. E. Denton, J. F. Drake, and R. G. Kleva, “ The m = 1 convection cell and sawteeth in tokamaks,” Phys. Fluids 30(5), 1448–1451 (1987).
A. Y. Aydemir, “ Nonlinear studies of m = 1 modes in high-temperature plasmas,” Phys. Fluids B: Plasma Phys. 4(11), 3469–3472 (1992).
F. D. Halpern, H. Lütjens, and J-F Luciani, “ Diamagnetic thresholds for sawtooth cycling in tokamak plasmas,” Phys. Plasmas 18(10), 102501 (2011).
C. R. Sovinec, A. H. Glasser, T. A. Gianakon, D. C. Barnes, R. A. Nebel, S. E. Kruger, D. D. Schnack, S. J. Plimpton, A. Tarditi, M. S. Chu, and the NIMROD Team, “ Nonlinear magnetohydrodynamics simulation using high-order finite elements,” J. Comput. Phys. 195(1), 355–386 (2004).
M. G. Schlutt, C. C. Hegna, C. R. Sovinec, S. F. Knowlton, and J. D. Hebert, “ Numerical simulation of current evolution in the Compact Toroidal Hybrid,” Nucl. Fusion 52(10), 103023 (2012).
J. A. Breslau, C. R. Sovinec, and S. C. Jardin, “ An improved tokamak sawtooth benchmark for 3D nonlinear MHD,” Commun. Comput. Phys. 4(3), 647–658 (2008).
S. P. Hirshman and J. C. Whitson, “ Steepest-descent moment method for three-dimensional magnetohydrodynamic equilibria,” Phys. Fluids 26(12), 3553–3568 (1983).
G. L. Jahns, M. Soler, B. V. Waddell, J. D. Callen, and H. R. Hicks, “ Internal disruptions in tokamaks,” J. Comput. Phys. 18(5), 609–628 (1978).
A. Y. Aydemir, J. Y. Kim, B. H. Park, and J. Seol, “ On resistive magnetohydrodynamic studies of sawtooth oscillations in tokamaks,” Phys. Plasmas 22(3), 032304 (2015).
E. T. Meier, V. S. Lukin, and U. Shumlak, “ Spectral element spatial discretization error in solving highly anisotropic heat conduction equation,” Comput. Phys. Commun. 181(5), 837–841 (2010).
Article metrics loading...
Numerical MHD simulations are used to gain insight into how sawteeth are affected by three-dimensional shaping from the Compact Toroidal Hybrid (CTH) stellarator field. CTH is a small stellarator-tokamak hybrid and sawteeth are sometimes seen on soft x-ray signals when operating with tokamak like profiles. We use NIMROD to compute numerical solutions having repeated sawtooth relaxations for a sequence of configurations with increasing helical stellarator field strength. The experimentally observed trend of the sawtooth period decreasing as the helical field strength is increased is recovered in the simulations. Careful attention to numerical convergence was required to obtain the results, and these considerations may be relevant to simulations of other phenomena in devices with non-axisymmetric plasmas such as perturbed tokamaks, RFPs, and stellarators.
Full text loading...
Most read this month