Fundamental and Applied Studies of Laser Plasma Accelerators
(2026)- Abstract
- Conventional radio-frequency acceleration form the basis of most accelerators in industry today, and is a scaleable technology used in large-scale research laboratories all over the world. The final particle energy and the availability of the devices are, however, often limited by practical concerns such as price, size, and energy consumption. This prompts research into alternative acceleration mechanisms, among which laser wakefield acceleration has emerged as a demonstrated method for compact electron acceleration and X-ray production. Here, a short laser pulse is focused to high intensities (> 1018 W/cm2) in a gas, ionising the medium and displacing plasma electrons from the laser pulse. This forms an ion cavity... (More)
- Conventional radio-frequency acceleration form the basis of most accelerators in industry today, and is a scaleable technology used in large-scale research laboratories all over the world. The final particle energy and the availability of the devices are, however, often limited by practical concerns such as price, size, and energy consumption. This prompts research into alternative acceleration mechanisms, among which laser wakefield acceleration has emerged as a demonstrated method for compact electron acceleration and X-ray production. Here, a short laser pulse is focused to high intensities (> 1018 W/cm2) in a gas, ionising the medium and displacing plasma electrons from the laser pulse. This forms an ion cavity trailing behind the laser pulse, which can accelerate electrons with gradients of hundreds of GV/m, three to four orders of magnitude higher than in conventional accelerators. While highly promising, significant work remains on understanding, controlling, and scaling the acceleration, all while preserving useful beam properties.
This thesis is a stepping stone in this direction, compiling fundamental studies, development work, and research applications of laser wakefield acceleration. The sensitivity of the electron and X-ray pulses to pulse-front tilt in the driving laser pulse is assessed. The X-rays are applied to time-resolved liquid mass measurements of sprays from a gasoline direct injector. Using two independent gas jets for the laser wakefield accelerator, the plasma profile is tailored to focus and increase the energy of the electrons. This is also used to generate X-rays with reduced divergence.
During the thesis work, a multi-terawatt titanium-sapphire laser system is replaced by an optical parametric amplification laser system, with shorter pulse durations. Using these few-cycle laser pulses, energy-bunched electron beams are produced. These give insight into the fundamental ionisation mechanisms used to inject electrons into the wakefield. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/7dae9c5b-1bbf-44a6-bac3-bb01acc031a6
- author
- Löfquist, Erik LU
- supervisor
- opponent
-
- Prof. Downer, Michael, University of Texat at Austin, USA.
- organization
- alternative title
- Fundamentala och applicerade studier av laser-plasma acceleratorer
- publishing date
- 2026
- type
- Thesis
- publication status
- published
- subject
- keywords
- Laser wakefield acceleration, LWFA, Laser plasma acceleration, Particle acceleration, Electron acceleration, X-ray generation, Plasma lens, Applications, Tomography, Beam steering, Pulse-front tilt, Spatio-temporal couplings, Ionisation injection, Laserdriven partikelacceleration, LWFA, Laser-plasma acceleration, Partikelacceleration, Elektronacceleration, Röntgengenerering, Plasmalins, Tillämpningar, Tomografi, Strålstyrning, Spatiotemporära kopplingar, Jonisationsinjektion
- publisher
- Department of Physics, Lund University
- defense location
- Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund.
- defense date
- 2026-02-13 09:15:00
- ISSN
- 0281-2762
- ISBN
- 978-91-8104-802-5
- 978-91-8104-803-2
- project
- Fundamental and Applied Studies of Laser Plasma Accelerators
- language
- English
- LU publication?
- yes
- id
- 7dae9c5b-1bbf-44a6-bac3-bb01acc031a6
- date added to LUP
- 2026-01-15 11:05:31
- date last changed
- 2026-01-19 11:04:39
@phdthesis{7dae9c5b-1bbf-44a6-bac3-bb01acc031a6,
abstract = {{Conventional radio-frequency acceleration form the basis of most accelerators in industry today, and is a scaleable technology used in large-scale research laboratories all over the world. The final particle energy and the availability of the devices are, however, often limited by practical concerns such as price, size, and energy consumption. This prompts research into alternative acceleration mechanisms, among which laser wakefield acceleration has emerged as a demonstrated method for compact electron acceleration and X-ray production. Here, a short laser pulse is focused to high intensities (> 10<sup>18</sup> W/cm<sup>2</sup>) in a gas, ionising the medium and displacing plasma electrons from the laser pulse. This forms an ion cavity trailing behind the laser pulse, which can accelerate electrons with gradients of hundreds of GV/m, three to four orders of magnitude higher than in conventional accelerators. While highly promising, significant work remains on understanding, controlling, and scaling the acceleration, all while preserving useful beam properties. <br/><br/>This thesis is a stepping stone in this direction, compiling fundamental studies, development work, and research applications of laser wakefield acceleration. The sensitivity of the electron and X-ray pulses to pulse-front tilt in the driving laser pulse is assessed. The X-rays are applied to time-resolved liquid mass measurements of sprays from a gasoline direct injector. Using two independent gas jets for the laser wakefield accelerator, the plasma profile is tailored to focus and increase the energy of the electrons. This is also used to generate X-rays with reduced divergence. <br/><br/>During the thesis work, a multi-terawatt titanium-sapphire laser system is replaced by an optical parametric amplification laser system, with shorter pulse durations. Using these few-cycle laser pulses, energy-bunched electron beams are produced. These give insight into the fundamental ionisation mechanisms used to inject electrons into the wakefield.}},
author = {{Löfquist, Erik}},
isbn = {{978-91-8104-802-5}},
issn = {{0281-2762}},
keywords = {{Laser wakefield acceleration; LWFA; Laser plasma acceleration; Particle acceleration; Electron acceleration; X-ray generation; Plasma lens; Applications; Tomography; Beam steering; Pulse-front tilt; Spatio-temporal couplings; Ionisation injection; Laserdriven partikelacceleration; LWFA; Laser-plasma acceleration; Partikelacceleration; Elektronacceleration; Röntgengenerering; Plasmalins; Tillämpningar; Tomografi; Strålstyrning; Spatiotemporära kopplingar; Jonisationsinjektion}},
language = {{eng}},
publisher = {{Department of Physics, Lund University}},
school = {{Lund University}},
title = {{Fundamental and Applied Studies of Laser Plasma Accelerators}},
url = {{https://lup.lub.lu.se/search/files/239612791/AvhandlingDigitalVersionOffentlig.pdf}},
year = {{2026}},
}