Radiographic applications and control of TNSA proton beams
type: CreativeWork
description: The interaction of a high intensity laser pulse with a thin solid target can drive the acceleration of protons and other heavier ions to multi MeV energies. The resulting ion beam has unique properties such as low transverse emittance, short pulse duration, high particle flux, large beam divergence and a broad energy spectrum. For applications, some of these properties are highly desirable and better than those which can be achieved with conventional accelerator technology. Others however, are detrimental for applications and require improvement. This thesis presents work aimed at exploiting these properties for radiographic purposes and exerting control over the ion beam properties for other applications. A divergent and broadband laser driven proton beam was used in the proton radiography technique to investigate the late stages of the interaction of an ablated plasma created by a ∼ 1014 W cm−2 laser with a solid target, expanding into a low density background plasma. The high temporal and spatial resolution obtained with proton radiography, combined with the large temporal window achieved, allowed the detection of the late stages of the evolution of electrostatic collisionless shocks. The evolution of the measured electrostatic potential associated with the shock front, and the qualitative observations seen in the Radio Chromic Film reveals the splitting of the shock front into two separate forward and reverse shocks in the shock frame, in agreement with simulations. Additionally, experimental measurements and comparison to simulations show that the shock potential is high enough to reflect some of the incoming upstream ions, stabilising the electrostatic shock. These shock reflected ions are also observed to be the cause of the ion-ion instability which is seen to develop at later times. This is seen to propagate through the shock features, destroying them in the processes, due to the similarity of the associated electric fields of the shock front and the instab…
abstract: The interaction of a high intensity laser pulse with a thin solid target can drive the acceleration of protons and other heavier ions to multi MeV energies. The resulting ion beam has unique properties such as low transverse emittance, short pulse duration, high particle flux, large beam divergence and a broad energy spectrum. For applications, some of these properties are highly desirable and better than those which can be achieved with conventional accelerator technology. Others however, are detrimental for applications and require improvement. This thesis presents work aimed at exploiting these properties for radiographic purposes and exerting control over the ion beam properties for other applications. A divergent and broadband laser driven proton beam was used in the proton radiography technique to investigate the late stages of the interaction of an ablated plasma created by a ∼ 1014 W cm−2 laser with a solid target, expanding into a low density background plasma. The high temporal and spatial resolution obtained with proton radiography, combined with the large temporal window achieved, allowed the detection of the late stages of the evolution of electrostatic collisionless shocks. The evolution of the measured electrostatic potential associated with the shock front, and the qualitative observations seen in the Radio Chromic Film reveals the splitting of the shock front into two separate forward and reverse shocks in the shock frame, in agreement with simulations. Additionally, experimental measurements and comparison to simulations show that the shock potential is high enough to reflect some of the incoming upstream ions, stabilising the electrostatic shock. These shock reflected ions are also observed to be the cause of the ion-ion instability which is seen to develop at later times. This is seen to propagate through the shock features, destroying them in the processes, due to the similarity of the associated electric fields of the shock front and the instab…
author: Hodge, Thomas
language: eng
date published: 2020-12
date modified: 2026-07-24T03:55:31Z
provider: Queen's University Belfast
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Queen's University Belfast