LOWER-HYBRID ACCESSIBILITY IN A LARGE, HOT REVERSED-FIELD PINCH

Accessibility and damping of the slow wave in a reversed field pinch ( RFP) plasma is investigated theoretically, using projected Reversed Fi eld Experiment (RFX) plasma parameters. By numerically solving the hot plasma dispersion relation, regions of propagation are found and the possibility of mode conversion is analysed. If the parallel index of r efraction of the wave is chosen judiciously at the edge of the plasma. the slow wave is accessible to a target region located just inside th e reversal surface without mode conversion. Landau damping is also opt imized in this region. A representative fast electron population is th en added in order to determine its effect on accessibility and damping . The presence of these electrons, whose parameters were estimated by extrapolation of Madison Symmetric Tents (MST) data, does not affect t he accessibility of the wave. However. the initial phase velocity of t he wave needs to be increased somewhat in order to maintain optimal da mping in the target zone.