A Resonantly Coupled, Ferrite-Tuned Buncher-Cavity System for the Los Alamos Proton Storage Ring
Resonantly coupled buncher and ferrite-loaded tuning cavities at 503.125 MHz are separately optimized to provide fast tracking of time-dependent beam current changes in the Los Alamos Proton Storage Ring (PSR) while maximizing radio-frequency (rf) stability and efficiency.
Ferrite-Tunable Microwave Cavities and the Introduction of a New Reflectionless, Tunable Microwave Filter
Large ferrite samples are placed in microwave cavities with the object of achieving tunable microwave cavities. Experimental data, at X band frequencies, on ferrite tuning of conventional band-pass and band elimination cavities are presented. Curves of applied dc magnetic field vs cavity resonant frequency, bandwidth, loss, cavity Q, and window coupling coefficients are included. Of particular interest are the results obtained with a new type cavity filter. With a single circularly polarized cavity, a reflectionless filter is achieved which couples nearly 100 per cent of the energy from the main waveguide at the cavity resonant frequency. Experimental results, on the ferrite loading of these circularly polarized cavities, are presented, and a number of practical microwave applications are discussed.
Ionization by drift and ambipolar electric fields in electronegative capacitive radio frequency plasmas.
Unlike α- and γ-mode operation, electrons accelerated by strong drift and ambipolar electric fields in the plasma bulk and at the sheath edges are found to dominate the ionization in strongly electronegative discharges. These fields are caused by a low bulk conductivity and local maxima of the electron density at the sheath edges, respectively. This drift-ambipolar mode is investigated by kinetic particle simulations, experimental phase-resolved optical emission spectroscopy, and an analytical model in CF(4). Mode transitions induced by voltage and pressure variations are studied.