Observation of Microwave Scattering from Large-Amplitude Oscillations in an Alkali Plasma

Microwave scattering has been observed from large-amplitude ion waves in a Cs plasma. The ion wave frequency was 24 kHz. The density fluctuations were 10% of the plasma density, which was approximately 4×${10}^9$ ${\mathrm{cm}}^{-3\mathrm{}}$. An "average" cross section has been obtained for the observed scattering. The result is of the order of ${10}^{-14\mathrm{}}$ ${\mathrm{cm}}^2$. Such a large value of the cross section is due to the high level of excitation of the ion wave. In the present experiment nonlinear effects play an important role.