Steady-State Orbitron Emissions
The Orbitron maser has been operated at a pressure of 2 × 10-6 in the steady state. Electrons are supplied to the device by an oxide-coated tungsten cathode placed inside the cylindrical cavity. The plasma-free emission corresponded to harmonically related steady-state narrow lines. The fundamental (lowest frequency) line corresponds to a resonance in the cavity system, which could be observed with a grid-dip meter.
Electrostatic electron cyclotron resonance maser with slotted coaxial waveguide
A new scheme of the electrostatic electron cyclotron resonance maser with slotted coaxial waveguide is presented here. Having studied it both in the linear and non linear regimes, we found that the radiation frequency and the converting efficiency could be increased largely for the low-energy electron beam in this scheme. The maximum converting efficiency of electrons with the π azimuthal mode can reach 23%. It has been revealed that there exist azimuthal and radical electron benching phenomena, corresponding to the kinetic and potential energy converting processes of electrons with the RF field. This revelation is helpful when looking into the physics of the electrostatic electron cyclotron resonance masers and other kinds of microwave devices with an electrostatic centrifugal field
Landau Damping for Students
By using the linearized equations of motion for particle streams, and by properly including the initial conditions, Landau's equations for electrostatic wave propagation with the correct damping decrement are easily obtained. No Vlasov equation, Laplace transform, contour integration, evaluation of residues at singularities, or analytical continuation is required. A discussion of the validity of the linearization is included.