Plasma Physics Seminar ( Phys 769)

P. N. Guzdar, IREAP A theory of the High confined (H)-mode in tokamak plasmas The tokamak plasma undergoes spontaneous improvement in confinement by creating a transport barrier in the edge region when the input power exceeds a critical value. Such a well-confined mode is called an H-mode. The transport barrier is believed to be caused by a poloidal flow shear layer which supresses fluctuations and inhibits radial transport. The new edge equilibrium leads to an improved global confinement and is hence a desireable feature of future fusion machines. I will briefly review existing theories for the edge barrier region and discuss our recently developed theretical model. The theory will be compared to data on some exisitng tokamaks.