Generation and features of the radio frequency (RF) hollow cathode discharge (HCD) are compared for the atmospheric and moderate pressures. The atmospheric-pressure plasma systems, fused hollow cathode (FHC) and hybrid hollow electrode-activated discharge (H-HEAD), are described. Examples of applications where both FHC and H-HEAD have already been employed are given, and potentials for new proc...

Radio-frequency capacitively coupled plasmas that incorporate structured electrodes enable increases in the electron density within spatially localized regions through the hollow cathode effect (HCE). This enables enhanced control over the spatial profile of the plasma density, which is useful for several applications including materials processing, lighting and spacecraft propulsion. However, ...

Three-dimensional V₂O₅ hollow structures have been prepared through a simple synthesis strategy combining solvothermal treatment and a subsequent thermal annealing. The V₂O₅ materials are composed of microspheres 2-3 μm in diameter and with a distinct hollow interior. The as-synthesized V₂O₅ hollow microspheres, when evaluated as a cathode material for lithium-ion batteries, can deliver a speci...

Life-limiting processes in hollow cathodes are determined largely by the temperature of the electron emitter. To support cathode life assessment, a noncontact temperature measurement technique which employs a stepper motor-driven fiber optic probe was developed. The probe is driven inside the hollow cathode and collects light radiated by the hot interior surface of the emitter. Ratio pyrometry ...

Three-dimensional V2O5 hollow structures have been prepared through a simple synthesis strategy combining solvothermal treatment and a subsequent thermal annealing. The V2O5 materials are composed of microspheres 2–3 μm in diameter and with a distinct hollow interior. The as-synthesized V2O5 hollow microspheres, when evaluated as a cathode material for lithium-ion batteries, can deliver a speci...

the extraction of sputtered metal from high power impulse hollow Abstract. High power impulse hollow cathode sputtering is studied as a means to produce high fluxes of neutral and ionized sputtered metal species. A model is constructed for the understanding and optimization of such discharges. It relates input parameters such as the geometry of the cathode, the electric pulse form and frequency...

Behavior of the xenon dispenser hollow cathode is complex, exhibiting high through-anode ion emission, unusual particle energy distributions, and high plume erosion rates. The device may find new application as an ion micro-thruster. A flight-type hollow cathode was characterized using several diagnostic methods. Measurements involved a retarding potential analyzer, quadrupole mass spectrometer...

A laser-induced Schottky-effect-gated photocathode gun has been in use since 2006. This new type of gun utilizes a laser’s coherency to create a compact laser source using Z-polarization of the IR laser on the cathode. This Z-polarization scheme reduces the laser pulse energy by reducing the cathode work function due to the Schottky effect. Before this epoch-making scheme emerged as a concept, ...

With the exception of the 632.8 nm neon line all the important visible and ultraviolet cw gas laser lines belong to the spectra of ionized atoms. To achieve proper laser oscillation the excitation of the upper levels of these lines is of primary importance. High energy electrons are needed for this process. As such electrons are in high concentration in the hollow cathode discharge, it was obvi...