Low-noise microwave magnetrons by azimuthally varying axial magnetic field

Early microwave magnetrons

The first description of the static characteristics of a device called magnetron was described by A. W. Hull in 1921. The tube had a linear filament in a coaxial cylindrical plate. The plate cylinder was surrounded by a winding, used to generate a magnetic field. The radial electric field and the superimposed magnetic field forced electrons to follow circular orbits before reaching anode. If th...

Low - noise Instrumentation for Near - field Microwave Microscopy

Azimuthally Varying Guided Mode Resonance Filters

New and novel sensing schemes require optical functions with unconventional spatial light distributions, as well as complex spectral functionality. Micro-optical elements have shown some flexibility in their ability to spatially encode phase information using surface relief dielectrics. In this paper, we present a novel optical component that exploits the properties of optically resonant struct...

Coulomb Clusters in Axial Magnetic Field

The rotation of Coulomb clusters with different numbers of micron-sized particles is observed in an inductively coupled dusty plasma in the presence of an axial magnetic field. The rotation is found to be dependent on the particle number and configuration. Clusters with smaller numbers of particles require a higher magnetic field strength in order to initiate the rotation, the threshold magneti...

Quantum Mechanics in an Axial Magnetic Field

We make three remarks about the quantum theory of a charged particle moving in a time-independent, uni-directional magnetic field (which we take to be parallel to the z-axis). First, when the field is uniform, we comment on the relation between the wave-function on the one hand if it is chosen to be an eigenstate of momentum (leaving aside the trivial z-dependence) and hence non-normalizable, a...