LOWER HYBRID-RESONANCE FOR 2 MAGNETIC-FIELD CONFIGURATION IN LINEAR LISA MACHINE

We have observed experimentally that during lower hybrid heating, at the resonance layer, the electron parallel temperature increases, the plasma potential drops, and the energy loss and the electric field decrease, as the size of the resonance volume increases. The process of mode conversion near the lower hybrid resonance is studied through the electric field distribution, which is modified by collisional damping. The potential drop indicates the potential plug in the radial direction. The quality factor of the machine is comparable to that of a low-Q cavity resonator. The experiment was carried out in a linear mirror machine LISA (linear Spiegel apparatus), excited by a 28 MHz RF antenna, with a low-density weakly ionized plasma.