High-confinement mode

In plasma physics and magnetic confinement fusion, the high-confinement mode (H-mode) is a phenomenon observed in toroidal fusion plasmas such as tokamaks. In general, plasma energy confinement degrades as the applied heating power is increased. Above a certain characteristic power threshold, the plasma transitions from L-(low-confinement) to H-mode regime, where the particle and energy confinement is significantly enhanced.

The H-mode was discovered by Friedrich Wagner and team in 1982 on the ASDEX diverted tokamak. It has since been reproduced in all major toroidal confinement devices, and is foreseen to be the standard operational scenario of many future reactors, such as ITER.