Theoretical Analysis of Triple Liquid Stub Tuner Impedance Matching for ICRH on Tokamaks

The impedance matching is crucial for continuous wave operation of ion cyclotron resonance heating (ICRH) antennae with high power injection into plasmas. A sudden increase in the reflected radio frequency power due to an impedance mismatch of the ICRH system is an issue which must be solved for present-day and future fusion reactors. This paper presents a method for theoretical analysis of ICRH system impedance matching for a triple liquid stub tuner under plasma operational conditions. The relationship of the antenna input impedance with the plasma parameters and operating frequency is first obtained using a global solution. Then, the relations of the plasma parameters and operating frequency with the matching liquid heights are indirectly obtained through numerical simulation according to transmission line theory and matching conditions. The method provides an alternative theoretical method, rather than measurements, to study triple liquid stub tuner impedance matching for ICRH, which may be beneficial for the design of ICRH systems on tokamaks.