A cylindrically symmetric (azimuthal mode number m=0) resonant inductive (MO/RITM) radio frequency (rf) helicon wave high density plasma source is described. The source consists of an antenna and bell jar generator immersed in a diverging magnetic field. Plasma is generated in this upstream region and then is transported along the field lines into the low-field downstream processing chamber. A propagating wave is observed in the plasma with rf spatial distribution and propagation characteristics that obey the theoretical m=0 helicon wave dispersion relation. By varying the divergence of the source magnetic field, the wafer etch rate and etch uniformity can be controlled. Spatially resolved optical emission spectroscopy shows that molecular gases are almost completely dissociated near the plasma center and have a uniform radial distribution. Highly uniform plasma and neutral distributions are then produced at the wafer location, and have been used in a variety of etch applications.

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This paper r e v i w s the experimental status and recevt advances i n AlfvCn Wave Heating (AWH). We discuss the underlying physics of Alfven Wave Heating, as seen by the experiments. The use of AlfvCn Waves for plasna diagnosis is discussed. The results of plasna heating on TCA are s m a r i z e d . Apparent changes i n the current profile are inferred, caused by changes i n the evolving AlfvCn wave spectrun excited. The implications for AWH on larger devices are mentioned. KFrwoRDsAlfven Wave Heating; Tokamak; Kinetic Alfvgn Wave; Profile Cor?trol; Antema Systen; plasm Diagnostics; Tc9. IMTR3DilCTIONI n t h i s paper we shall review the recent experiwntal results obtained i n AlfvCn Wave Heating (AXH). The early experimental results have already been reviewed by Shohet (1978), and w shall not repeat that survey. An overview of the extensive theoretical mrk i n Lhis freqency range is beyond t h i s paper, and the current status has been very recently reviewed by Pppert and colleagues (1586). W e shall review the theoretical basis of .MX frm. the viewpint of the experimental observations made, and shall, i n f a c t , discover that mst of the imprtant concepts manifest themselves i n the results.

In this paper, we present the most recent results obtained during the Alfvgn wave Heating experiments being carried out on the TCA Tokamak. We have obtained both significant electron heating and some ion heating using rf powers up to 230 kW, greater than the value of the ohmic heating power in the tarqet plasma. Firstly, we shall describe the AWH method as applied to TCA and then briefly cover some of the low power experiments carried out during the last year. The higher power experiments will then be discussed, alonq with some of the problems we have encountered.Recent Alfvgn Wave Heating Results on the TCA Tokamak I 1 lo I #14329-38 15kG.q-3.3 (N, M 1 = (2.1) / O ev -200

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