“…In this letter we report preliminary experimental evidence indicating the enhancement of the supersonicsubsonic flow transition and shock formation of a dense plasma beam by externally applied microwaves at the ion plasma frequency. The phenomenon of the supersonic-subsonic flow transition and shock formation and propagation of a dense plasma stream flowing longitudinally in a converging magnetic field channel has been studied analytically by LeLoup and Taussig [1] and Asano [2], experimentally by Uchida et al [3], Siambis et al [4], Kramer and Siambis [5], Johnson and Siambis [6], Toffolo and Siambis [7] and Toffolo [8], and by means of computer simulation by Freeman [9]. In the work presented in this paper, the experimental configuration is identical to that of Ref.…”