Radiated plasma waves from modulated charged particle beams

Plasma wave excitations by localized ''modulated'' charged particle beams are investigated experimentally and theoretically. The localized modulated electron and ion beams can launch various kinds of controlled plasma waves. This method for an excitation of plasma waves has several merits: there is no need to use solid conductors; it is possible to launch plasma waves in a far region from the beam source; it is possible to be used even in high temperature plasmas, etc. This method can be useful for a heating of plasmas. For a fixed modulation frequency, the wave number k11 along the beam can be determined as k11 = ω/V /sub o/ , (V /sub o/ : the beam velocity). The excitation efficiency of plasma waves and gyclotron waves et al. are investigated, and those radiated waves are spatially investigated. Typical example of the radiated wave from k11-launcher are indicated in the following figure