Application of microwave reflectometry to register Alfvén wave resonances in the TCABR tokamak

Application of microwave reflectometry to study Alfvén wave resonances in the TCABR tokamak is described. A microwave reflectometer was used to register plasma density oscillations driven by the excited Alfvén waves, under the condition of the spectrum scanned by a controlled plasma density rise. It is shown that when the position of the local Alfvén resonance r A , which is defined by the relation ω=k ∥ (r A )C A (r A ), is close to the plasma zone where the microwave signal is reflected, the high-frequency modulation of the output signal of the reflectometer at the rf generator frequency increases. This method can give information about the localization of the rf power deposition zone in Alfvén wave plasma heating and current drive experiments. It also allows finding the plasma current profile in the region of the rf power deposition.