A low frequency (100 MHz) cross-field amplifier device for measurements of RF wave-electron interactions

Summary Form only given, as follows. A new device has been constructed in order to investigate wave-particle interactions in a cross-field amplifier (CFA). This device will be used to make measurements of the electron plasma, RF fields, and noise sources in an operating CFA using standard plasma diagnostics. Investigations of ponderomotive force effects on phenomena such as soliton formation and convective cells are also planned. The slow wave circuit is 40 cm long and 25 cm wide. An amplifier can provide up to 250 W of power at a frequency of 100 MHz. The slow wave wavelength is predicted to be 4 cm. The characteristic impedance of the circuit is predicted to be 55 Omega so matching problems should not be significant. The static magnetic field is provided by two coil sets configured as Helmholtz coils with fields up to 80 G. The cathode is made of Al-2024 and can be biased to -2.5 kV. In addition, there are tungsten filaments for the first 10 cm of the cathode in order to provide a good starting electron density as well as to allow for control of that density. Directional couplers are used to provide power measurements.<>