EXCITATION OF SIDE-BAND EMISSIONS BY A MODULATED ELECTRON-BEAM DURINGTHE CHARGE-2B MISSION

Sideband wave emissions are secondary peaks in wave power observed at frequencies above and below the primary peak. Observed sideband amplit udes are usually reduced compared to the primary wave amplitude. Durin g the recent CHARGE 2B ionospheric rocket mission, sideband waves were observed during an electron beam injection experiment. The beam curre nt was modulated causing a peak in wave power at the modulation freque ncy and at certain times sidebands were observed along with the primar y wave emission. A nonlinear coupling mechanism between the primary wa ve and a lower-frequency wave is explored here to explain the presence of the sideband emissions. Comparison of the theoretical results with the wave data confirm this mechanism as a viable explanation for the observed sidebands.