Observation of centripetal wave propagations in a linear turbulently heated plasma using microwave scattering

Centripetal propagation of low frequency waves of f≃20∼30 MHz are observed in a linear turbulently heated plasma, using a 70 GHz microwave scattering. The scattered radiations are detected with a heterodyne detection system which has a feedback-loop for stabilizing the difference frequency between the incident and local ones. A narrow spectrum which is initially observed and corresponds to the waves propagating toward the axis of the cylindrical plasma, tends to spread toward low frequency region, and in a later time an approximately symmetrical distribution is realized. (author)