Emission of whistler waves by a density modulated electron beam is studied in a laboratory plasma and compared to excitation by loop antenna. Single and double pole excitation are predicted by a simple linear model which agrees with the experiments. The fraction of the power of the modulated beam radiated by the whistler wave has been measured and is of the order of ${10}^{\mathrm{-}5}$.

• Received 19 July 1993

DOI:https://doi.org/10.1103/PhysRevLett.72.649