Plasma Flow-Shear Driven Instabilities and Efficient Cyclotron-Wave Absorption in Open Magnetic-Field Configurations

The two plasma sources using a concentrically three-segmented plasma emitter are developed, with which the parallel and perpendicular flow shears can be controlled, respectively. Here the drift-like and Kelvin-Helmholtz instabilities are observed to be excited and suppressed depending on the parallel and perpendicular flow shears, respectively. On the other hand, propagation and absorption of right-hand (R) and left-hand (L) circularly polarized waves, which are related to plasma heating, are investigated under magnetic-mirror configurations. Not only R wave but also L wave is absorbed in the electron cyclotron resonance (ECR) region in the same way, which is considered to be caused by the polarization reversal from the L wave to the R wave. It is actually observed that the L wave is converted into the R wave near the ECR point depending on the electron temperature.