Strong Interaction of Low-Power Electron Beams with the Ionosphere

The late stages of the beam-plasma instability are not yet completely understood. A better knowledge of the evolution of the beam is necessary to explain the results of the electron beam experiments carried out in the ionosphere. An alternative to the complete stabilization by quasi-linear (QL) diffusion is the parametric "stabilization." In this case the beam remains unstable for very long distances, while retaining its "hot-beam" characteristics. A recent flight provides data that indicate the relevance of this mechanism in the evolution of the beam-plasma instability.