Theoretical analysis of thermal dike supported by electron cyclotron resonance heating

Thermal dike is a new concept for controlling energy transport carried by electrons along open magnetic field lines by enhancing mirror‐reflection with assistance of electron cyclotron resonance heating (ECRH). Quantitative analyses are made to evaluate merits of thermal dike and to clarify requirements for efficient use of it. Heating response function is applied for trajectory analyses of electrons streaming through the ECRH zone. Substantial power gain is obtained under a configuration with a high mirror ratio between the reflection point and the resonance point and with a large scale length of the magnetic gradient in the resonance zone. Thermal dike is shown to be beneficial both in tandem mirrors and in diverters in tori. Discussions are made also on a basic experiment program of thermal dike in the GAMMA 10 tandem mirror.