Nonlinear mode conversion of intense ordinary waves into electrostatic upper-hybrid waves

Abstract

A high-power ordinary wave launched from the low field side is observed to undergo nonlinear mode conversion process and is partially transformed into a short-wavelength electrostatic upper-hybrid wave at the upper-hybrid layer. The nonlinear conversion process can be explained as due to a periodic modulation of upper-hybrid frequency at twice its value, while the frequency modulation comes from the combination of electron mass oscillation and oscillating density modulation induced by the ordinary wave.