Abstract
A simple numerical model is proposed for modeling the possibility of the LH-transition (transition to improved plasma confinement state) being triggered by a burst of radial electric field oscillations in a tokamak. One-dimensional density evolution is considered to be governed by an anomalous diffusion coefficient dependent on radial electric field shear (spatial inhomogeneity measure). The radial electric field is taken as the sum of oscillating term and quasi-stationary one determined by density and ion temperature gradients through neoclassical formula. If oscillating field parameters (amplitude, frequency etc) are properly adjusted, a transport barrier forms at the plasma periphery and sustains after oscillations are switched off, manifesting a transition into high confinement mode with strong inhomogeneous radial electric field and suppressed transport at the plasma edge. Electric field oscillation parameters required for LH-transition triggering are compared with geodesic acoustic mode parameters observed at the TUMAN-3N tokamak in the ohmic LH-transition discharges. It is concluded on the basis of this comparison that the geodesic acoustic mode may act as a trigger for the LH transition.
Similar content being viewed by others
References
P. Diamond, S.-I. Itoh, K. Itoh, and T. S. Hahm, Plasma Phys. Control. Fusion 24, R35 (2005).
A. Fujisawa, T. Ido, A. Shimizu, et al., Nucl. Fusion 47, S718 (2007).
A. Fujisawa, Nucl. Fusion 49, 013001 (2009).
L. G. Askinazi, M. I. Vildjyunas, N. A. Zhubr, A. D. Komarov, V. A. Kornev, S. V. Krikunov, L. I. Krupnik, S. V. Lebedev, V. V. Rozhdestvensky, M. Tendler, A. S. Tukachinsky, and S. M. Khrebtov, Tech. Phys. Lett. 38 (3), 268 (2012).
V. V. Bulanin et al., Proceedings of the 40th EPS Conference on Plasma Physics (Helsinki, 2013).
L. G. Askinazi et al., Proceedings of the 38th EPS Conference on Plasma Physics (Strasbourg, 2011).
V. A. Rozhansky, Plasma Phys. Control. Fusion 46, A1 (2004).
G. M. Staebler, Plasma Phys. Control. Fusion 40, 569 (1998).
T. S. Hahm et al., Phys. Plasmas 6 (3), 922 (1999).
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © L.G. Askinazi, A.A. Belokurov, 2015, published in Pis’ma v Zhurnal Tekhnicheskoi Fiziki, 2015, Vol. 41, No. 22, pp. 25–31.
The article was translated by the authors.
Rights and permissions
About this article
Cite this article
Askinazi, L.G., Belokurov, A.A. The possibility of geodesic acoustic mode-initiated LH-transition in the TUMAN-3M tokamak. Tech. Phys. Lett. 41, 1080–1082 (2015). https://doi.org/10.1134/S1063785015110164
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1063785015110164