Study of the beam profile and position instability of a post-accelerated pseudospark-sourced electron beam

Abstract

This version is available at https://strathprints.strath.ac.uk/60089/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. A pseudospark-sourced electron beam is a promising candidate for driving a THz millimeter wave radiation source. However, the physics governing the electron beam density profile and the beam center deviation from the axis of the structure, which may be caused by the randomness in the pseudospark discharge process, remains still unclear especially for the high energy component of the pseudospark-sourced electron beam which is usually non-mono-energetic. It is essential to study the electron beam density profile and the beam center position distribution for optimizing the pseudospark discharge configuration. In this paper, images of some single-shot electron beam pulses have been captured using a 50 m thickness stopping copper foil and a phosphor screen coated with P47 scintillator to study the electron beam density profile and the beam center position distribution of the high energy component of the electron beam. The experiments have been carried out on two pseudospark discharge configurations with two different size hollow cathode cavities. The influence of the cathode aperture of each configuration has also been studied according to the beam images. Experimental results show that the beam profile of the high energy component has a Lorentzian distribution and is much smaller than the axial aperture size with the beam centers dispersing within a certain range around the axis of the discharge structure. The pseudospark-sourced electron beam with the larger hollow cathode cavity shows smaller full width at half maximum (FWHM) radius and a more concentrated beam center distribution.

Simulations of the Self-Focused Pseudospark-Sourced Electron Beam in a Background Ion Channel

“…The theoretical analysis and the previous simulations employed uniform electron beam density distribution profiles over the beam radius. However, the electron beam density measurement using a scintillator screen showed that the PS-sourced beam has a Gaussian-like density distribution and a beam waist of 0.5 mm [27]. The injected electron beam used was of the same overall current but different density distributions.…”

Compact high‐power millimetre wave sources driven by pseudospark‐sourced electron beams

“…The PS discharge goes through various complex discharge processes and depends primarily on the PS discharge configurations [24][25][26][27][28][29]. Since its discovery in 1978, efforts have been made to understand the PS discharge phenomena for the generation of high density and energetic electron beams by theoretical, plasma simulation, and experimental studies [9,18,24,[29][30][31][32][33][34][35][36][37][38]. Notably, PS discharges have been studied at the University of Strathclyde since 1994 with a series of experiments conducted on beam generation and microwave and millimetre wave sources driven by PS discharges.…”

Investigation of millimeter wave extended interaction oscillation using improved pseudospark-sourced electron beams

“…To achieve better beam quality, the PS-sourced electron beam is also investigated with post-acceleration to reduce its beam energy spread [8][9][10]. To achieve higher output power, a sheet beam EIO structure is further studied with a PS-sourced sheet beam [11].…”