January 2011

Journal

High-Beta, Improved Confinement Reversed-Field Pinch Plasmas at High Density

By:
Wyman, M.; Chapman, B. E.; Ahn, J.; Almagri, A.; Anderson, J.; Bonomo, F.; Brower, D. L.; Combs, Stephen K; Craig, D.; Hartog, D. J. Den; Deng, B.; Ding, W. X.; Ebrahimi, F.; Ennis, D.; Fiksel, G.; Foust, Charles R; Franz, P.; Gangadhara, S.; Goetz, J.; O'Connell, R,; Oliva, S.; Prager, S. C.; Reusch, J.; Sarff, J. S.; Stephens, H.; Yates, T.
Journal Name:
Physics of Plasmas
Page Number:
10701
Volume:
15
Issue Number:
1
Publication Date:
January 2011
View DOI Listing:
https://doi.org/10.1063/1.2835439

Abstract

In Madison Symmetric Torus Dexter et al., Fusion Technol. 19, 131 1991 discharges where improved confinement is brought about by modification of the current profile, pellet injection has quadrupled the density, reaching ne=41019 m−3. Without pellet injection, the achievable density in improved confinement discharges had been limited by edge-resonant tearing instability. With pellet injection, the total beta has been increased to 26%, and the energy confinement time is comparable to that at low density. Pressure-driven local interchange and global tearing are predicted to be linearly unstable. Interchange has not yet been observed experimentally, but there is possible evidence of pressure-driven tearing, an instability usually driven by the current gradient in the reversed-field pinch.