7th International Reflectometry Workshop for Fusion Plasma Diagnostics, 9-12 de Maio de 2005, Garching, Alemanha

	Experimental Studies of the Registration of Alfvén Wave Resonances in the TCABR Tokamak by the Frequency Scanning Reflectometry
	L. F. Ruchko, R. M. O. Galvão, A. G. Elfimov, J. I. Elizondo, E. Sanada, Yu. K. Kuznetsov , A. M. M. Fonseca, V. Bellintani Jr, A. N. Fagundes, I.C. Nascimento, W. P. de Sá, C.A.F. Varandas, M. Manso, P. Varela e A. Silva
	Resumo
	The experimental studies of the application of the frequency scanning microwave reflectometry to the analysis of the local Alfvén wave (AW) resonances are presented. These resonances are excited close to the magnetic surfaces, at which the local plasma Alfvén velocity is equal to the phase velocity of the electromagnetic wave, which is excited by the AW antenna system. These AW resonances manifest themselves as spatially radially localized plasma density oscillations at the AW frequency, and can be registered by the microwave scanning reflectometer technique. The experiments in the TCABR tokamak were carried out with the excitation of the AW modes M=±1, N=±1, ±2, ±3 at the frequency f=4.5 MHz. It is shown that the modulation of the reflectometer output signal at the AW frequency is increased when the position of the local Alfvén resonance is close to the plasma zone where the reflectometer microwave signal is reflected. The continuous sweeping of the reflectometer frequency in the course of the plasma discharge makes it possible to track the Alfvén zone position.