ENHANCEMENT OF ABSORPTION OF LOWER-HYBRID WAVE BY FILLING THE SPECTRAL GAP

The interaction between a lower hybrid wave (LHW) and electrons in a plasma has been investigated. An LHW of low phase velocity was injected into a plasma in addition to a high phase velocity LHW to fill the spectral gap which lies between the phase velocity of the faster wave and the thermal velocity of the electrons. It was found that the absorption of the faster wave was enhanced at the plasma outer region by injecting these waves simultaneously. As a result the LH-driven current in the inner region of the plasma was reduced by the power absorbed in the outer region. The increase of the power absorption is attributed to the filling of the spectral gap by the slower wave.