PRODUCTION MECHANISM OF A LARGE-DIAMETER UNIFORM ELECTRON-CYCLOTRON-RESONANCE PLASMA GENERATED BY A CIRCULAR TE01 MODE MICROWAVE

To clarify the production mechanism of a large-diameter uniform electr on cyclotron resonance (ECR) plasma generated by a circular TE01 mode microwave experimentally, the wave propagation characteristic in the p lasma is measured with an interferometer. It is shown that a.microwave introduced into the chamber is transformed mainly into an electron cy clotron wave and then entirely absorbed around the resonance point. Fu rthermore, it is experimentally proven that the correspondence between the radial distribution of the electric field intensity of injected m icrowaves and that of waves propagating in plasma may depend on the ma gnetic field intensity around the injection point. It is also confirme d that it is necessary to optimize the magnetic field configuration to generate a uniform ECR plasma since the absorption region of microwav es is as wide as from omega/omega(ce) approximately 0.65 to adjacent t o the resonance point.