Non-Linear Coupling Between Slow and Fast Waves in a Wave-Guide Partially Filled with a Plasma

摘要

The non-linear coupling between different modes in a parallel plate wave-guide, partially filled with a cold and homogeneous plasma slab, is studied. The types of non-linearities considered are those arising in the equation of motion for the electrons and from the ac charges on the plasma boundaries. It is shown that, by means of a slow (or fast) pump wave, one slow primary wave can non-linearly excite another fast wave, which in contrast to the slow primary wave will have a considerable amount of field energy outside the plasma, and may thus be easily picked up by conventional couplers. Numerical calculations of the coupling coefficient are presented, and it is concluded that non-linear coupling in this way, at least for very slow primary waves, can provide a mean of getting an improved coupling to the slow plasma waves. (Author)