WHISTLER-MODE RADIATION FROM THE SPACELAB-2 ELECTRON-BEAM

During the Spacelab 2 mission the Plasma Diagnostics Package (PDP) performed a fly-around of the shuttle at distances of up to 300 meters while an electron beam was being ejected from the shuttle. We discuss a magnetic conjunction of the shuttle and the PDP while the electron gun was operating in a steady (DC) mode. During this conjunction, the PDP detected a clear funnel-shaped emission that is believed to be caused by whistler-mode emission from the beam. Ray-path calculations show that the shape of the funnel can be accounted for by whistler-mode waves propagating near the resonance cone. Because the beam and waves are propagating in the same direction, the radiation must be produced by a Landau, omega /k// parallel equals v//b, interaction with the beam. Other types of waves generated by the beam are also described.