Study of the Spatial Distribution of the Langmuir Wave Amplitude in the Turbulent Plasma using Electron Beam Shadowgraph Technique

摘要

New diagnostic, "electron-beam-shadowgraph", is examined for taking the spatial distribution of transient fields in a plasma. It is applied to the unmagnetized plasma, which is perturbed by an intense relativistic electron beam (IREB). Strong deflection is observed with duration of about 1 μs just after the IREB injection. The shadowgraph image is characterized by presence of aggregate holes. The size of the hole is changed with the plasma density, and corresponds to the 15 - 60 Debye lengths. Important agreements are observed between the experiment and the strong Langmuir turbulence theory.