スペースプラズマにおける電場形成とその効果 4.電場形成についての室内実験

抄録

Laboratory investigations on the formation of space-related electric fields have been performed using collisionless magnetized-plasma flows. In a set of experments, potential differences are externally applied along magnetic-field lines, different plasmas come into contact with each other under the currentless condition, a high-speed plasma flow is injected into a region of converging manetic-field lines, large-amplitude electron plasma waves are generated in a uniform magnetic field, and local electron-cyclotron resonances occur in various kinds of nonuniform magnetic fields. It is found that the elcetric field is formed in the region of density gradient, a U-shaped double layer (DL) is accompaned by ion-cyclotron oscillations, a DL is formed in the currentless system, and that an electron local-plug results in the formation of a potential dip and hump with a scale length of the order of Debye length. Electron- and ion-acceleration electric fields with a scale lengths of a magnetic-field gradient are also found to be formed by passing ions and electrons through nonuniform magnetic fields, respectively.