High confinement in fusion oriented plasmas with kV-order potential, ion, and electron temperatures with controlled radial turbulent transport in GAMMA 10

The tandem mirror system has achieved improved energy confinement times ($>$ 60-90 ms) with radial transport dominating the Pastukhov axial energy confinement time ($>$ 100 ms). This high confinement regime establishes a proof of principle that the combination of electrostatic and magnetic mirror confinement can successfully insulate electrons from thermal ions. ECH controlled hot-layer formation facilitates plasma-rotation profile formation with a radially localized high-vorticity layer. In the vicinity of the layer, a radial transport barrier is formed [1], showing similar properties to ITB in toroidal plasmas. Coaxially nested intense E(r)$\times $B sheared flow [2] in the GAMMA 10 core plasma realizes an upgraded stable regime having (i) $>$ 0.75 keV bulk central electron temperature with (ii) an achievement of larger stored energy for axially potential-confined ions exceeding that (i.e., diamagnetism) for central magnetically confined ions ($\approx $ 7 keV). The radially sheared flow having peak-on-axis high vorticity guards and improves whole core plasma confinement, and is controlled by (iii) improved $\approx $ 3 kV ion-confining potential due to simultaneous central and plug ECH. X-ray imaging of the suppression of turbulent structures [1-3] will be shown [1,2]. \newline [1] T. Cho et al., Phys. Rev. Lett. \textbf{97}, 055001 (2006). \newline [2] T. Cho et al., Phys. Rev. Lett. \textbf{94}, 085002 (2005). \newline [3] J. Pratt and W. Horton, Phys. Plasmas \textbf{13}, 042513 (2006). \newline \newline Collaborators; W. Horton$^{1}$, J. Pratt$^{1}$, M. Hirata, J. Kohagura, T. Numakura, H. Hojo, M. Ichimura, A. Itakura, T. Kariya, I. Katanuma, R. Minami, Y. Nakashima, M. Yoshikawa, Y. Miyata, Y. Yamaguchi, T. Imai, V. P. Pastukhov$^{2}$, S. Miyoshi, GAMMA 10 Group ($^{1}$IFS, Univ. Texas at Austin, $^{2}$Kurchatov Institute, Russia)