A key point of physics for sustaining fusion power steady output is to control the electron thermal transport in weak collisionality regime for electron confinement improvement, in order to heat fueling ions for the self-consistently burning. In 2020, the group has made a great progress on the scenario development and the underlying physics. The discharge pulse is elongated to 20s which is ten times long of the plasma current diffusion time scale. The results show that the key to obtain high electron temperature is the existence of multi-scale resonance between MHD mode and turbulence, and the important factor to sustain of such a scenario is keep MHD long-lived stationarity with stable harmonics. This result will be important for EAST to further lengthen this mode in the future, and to achieve 100 seconds/thousand seconds’ scenario with higher constraints in the future. It will provide important support for ITER and CFETR to find effective heating path for fuel ions and maintain plasma self-holding combustion.The findings are published in journals such as Nuclear Fusion.

First 20s quasi-steady plasma with Te0~9keV in EAST

Resonance between MHD and turbulence in plasma core holds the steep core Te profile

Steady MHD with stable harmonics sustains the long pulse high Te plasma