QUASI-OPTICAL GRILL LAUNCHING OF LOWER-HYBRID WAVES FOR A LINEARLY INCREASING PLASMA-DENSITY

An analysis of quasi-optical grills for lower-hybrid waves for heating and current drive purposes is presented. The tokamak plasma density v ersus the abscissa entering the plasma is assumed to behave like a ste p and a subsequent ramp. The study is performed by means of a two-dime nsional formulation employing cylindrical waves. A detailed numerical analysis is presented, which allows us to show results for different c onfigurations useful in practical cases and comparisons with the const ant-density case.