Cma Diagrams, Inverse Wave Normal Surfaces, And Fast And Slow Wave Propagation In The Lower Hybrid Range Of Frequencies

High-power plasma waves in the lower hybrid range of frequencies (LHRF) are being used for non-inductive current drive in experiments around the world. In this range, plasmas can support waves with two different polarizations, a quasi-electrostatic wave known as the "slow wave" or simply the lower hybrid wave, and a quasi-electromagnetic wave referred to variously as the "fast wave in the LHRF", "whistler", or "helicon". An improved qualitative understanding of how fast and slow waves in the LHRF propagate can be gained by studying the "inverse wave normal surface" or IWNS. It is shown that the two branches propagate in a qualitatively similar way, with, however, important quantitative differences.