Acoustic waves in plasma
Institute of Applied Problems of Physics, National Academy of Sciences of Armenia, Armenia
This is a review of studies of the interaction of acoustic waves and plasma. It is shown that the variation of parameters of an acoustic wave directed along the positive column of a gaseous discharge makes it possible to adjust continuously the plasma properties — in particular, to increase or decrease the gas and electron temperatures and the electric field intensity over a wide range. The issues considered are how sonic waves affect the compression (contraction) and expansion (decontraction) of the plasma column, and also the accompanying abrupt increases in wave amplitude and discharge current modulation. The mechanisms of the phenomena listed are examined. Analogies between processes which occur in plasma when sonic waves propagate in it and when gas flows through it are discussed. The results of studies of the combined effect of a sonic wave and a gas flow on the parameters of a gaseous discharge are presented.