A series of experimental study has been made on electron plasma oscillation excited by the interaction of an electron beam and a plasma in a magnetic field. The plasma under study was formed by a hot cathode discharge tube containing mercury drop, and was applied a magnetic field in parallel to its discharge current, thus the oscillation was detected in the frequency range of 25 Mc/s-1640 Mc/s by a super-regenerative detector and super-heterodyne receiver.
Two. types of discharge tubes i.e. of diode, and reflex type were used for the study. In either as, oscillation was detected. In case of the experiment by a diode discharge tube, especially, it was confirmed that the oscillation exists in the form of standing wave between the electrodes Among excited oscillations, the most prominent oscillation is the oscillation of ω
2-ωp
2type which is dependent upon plasma frequency but is independent of cyclotron frequency ω
H. This oscillation becomes weak when the magnetic field condition approaches to the condition of ω
d-ω
H·Further, detection of such oscillations in the vicinity of ω
d-ω
H is not available unless discharge current I
p is to be increased more than the discharge current in the case where the magnetic field, strength is strong enough.
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