Femtosecond Thermionic Emission in the Space-Charge Limited Regime

Uniformity for a Magnetron Injection Gun

We report measurements of the azimuthal emission nonuniformity of a gyrotron's thermionic cathode as determined from two experiments, one which determines the total emission and one which scans the emitted beam using a rotating probe. In the total emission experiment, which measured the total collector current over a range of voltages, the cathode's total work function spread was found to be 0....

Modeling of Space-Charge Effects in 3D Thermionic Devices

Photon-enhanced thermionic emission (PETE)[1] appears as a promising technology for electric power generation from renewable resources. Its combination of photovoltaic and thermionic effects leads to devices which can operate at high temperature through thermionic emission still exploiting efficient electrons promotion through a semiconductor band gap when it is chosen as a cathode. However, th...

Breakdown of a space charge limited regime of a sheath in a weakly collisional plasma bounded by walls with secondary electron emission.

A new regime of plasma-wall interaction is identified in particle-in-cell simulations of a hot plasma bounded by walls with secondary electron emission. Such a plasma has a strongly non-Maxwellian electron velocity distribution function and consists of bulk plasma electrons and beams of secondary electrons. In the new regime, the plasma sheath is not in a steady space charge limited state even ...

Enhanced Thermionic-Dominated Photoresponse in Graphene Schottky Junctions.

Vertical heterostructures of van der Waals materials enable new pathways to tune charge and energy transport characteristics in nanoscale systems. We propose that graphene Schottky junctions can host a special kind of photoresponse that is characterized by strongly coupled heat and charge flows that run vertically out of the graphene plane. This regime can be accessed when vertical energy trans...

Negative space charge effects in photon-enhanced thermionic emission solar converters