A theory for the pressure pedestal in high „H... mode tokamak discharges

When a tokamak plasma makes a transition into the good or the high confinement H mode, the edge density and pressure steepen and develop a very sharp pressure pedestal. Prediction of the height and width of this pressure profile has been actively pursued so as to provide a reliable extrapolation to future burning plasma devices. The double-Beltrami two-fluid equilibria of Mahajan and Yoshida fPhys. Plasmas 7, 635 s2000dg are invoked and extended to derive scalings for the edge pedestal width and height with plasma parameters: these scalings come out in agreement with the established semiempirical scalings. The theory predictions are also compared with limited published H-mode data and the agreement is found to be very encouraging. © 2005 American Institute of Physics. fDOI: 10.1063/1.1852468g