Whistler waves, Langmuir waves and single loss cone electron distributionsinside a magnetic cloud: Observations

Whistler waves propagating along the ambient magnetic field are observed wi thin a coronal mass ejection (on January 10, 1997) associated in time with Langmuir waves and electron distributions of a single loss cone type. In ad dition, background observations are made on the plasma wave activity in the sheath and foreshock regions that precede the magnetic cloud, on the obser ved radio emissions (including a type IJ, radio burst) and on the geometry of the cloud. All the data comes from the WIND spacecraft. The whistler wav es are identified using full magnetic waveforms while possible evidence of coexisting parallel, and antiparallel propagating Langmuir modes are found in the waveform and spectral wave data from the WAVES experiment. A few hun dred low energy electron distributions from the Three-Dimensional Plasma (3 DP) experiment are investigated. Finally, we tentatively suggest that this type of plasma wave particle activity is linked to the type II emission obs erved, i.e., that the emission mechanisms are proceeding and taking place w ithin the magnetic cloud instead of at the shock region as usually thought. The extra suprathermal electrons could source from electrons accelerated a t reconnection sites between the magnetic cloud and the ambient interplanet ary magnetic field. A linear instability study using observed properties of the electron distributions is to be presented in a following paper.