Intense laser-plasma interactions
Doktorsavhandling, 2019

In the interaction of ultra-intense laser fields with matter, the target is rapidly ionized and a plasma is formed. The ability of a plasma to sustain acceleration gradients, orders of magnitude larger than achievable with conventional accelerators, has led to a great interest in laser-driven plasma-based particle and radiation sources, with applications in materials science, biology and medicine.

In this thesis, two separate, yet highly related, topics are pursued. The first half of the thesis concerns plasma-based techniques for ion acceleration, through the interaction of intense laser fields with solid density targets. In the most accessible acceleration scheme, the ion acceleration is mediated by a population of suprathermal, hot, electrons produced by the rapid heating of the target surface. We study the effect of adding microstructures to the target surface, show how this affects the distribution of hot electrons and discuss its implications for ion acceleration. We further study a novel acceleration scheme, aimed at achieving controllable ion acceleration using a frequency chirped standing wave. We analyse the robustness of this scheme, named chirped-standing-wave acceleration, under non-ideal conditions and discuss its prospects and limitations.

The second half of the thesis concerns laser-matter interactions where the emission of high-energy photons necessitates a quantum mechanical description of radiation reaction and enables a prolific production of electron-positron pairs. In this regime, we study the interaction of an energetic electron beam with an optimally focused laser field, in the form of a dipole wave, and highlight its capabilities as a multi-GeV photon source. We further discuss the phenomena observed in this setup, in particular investigating the emergence of pair production cascades, and provide a review of previous results. Finally, we highlight a number of regimes within reach of upcoming laser facilities.

ion acceleration

plasma

laser

radiation generation

particle-in-cell

radiation reaction

pair production cascades

PJ-salen, Fysikgården 2, Chalmers
Opponent: Laurent Gremillet, CEA, Frankrike

Författare

Joel Magnusson

Chalmers, Fysik, Teoretisk fysik

Multiple-colliding laser pulses as a basis for studying high-field high-energy physics

Physical Review A - Atomic, Molecular, and Optical Physics,; (2019)

Artikel i vetenskaplig tidskrift

Laser-particle collider for multi-GeV photon production

Physical Review Letters,; Vol. 122(2019)

Artikel i vetenskaplig tidskrift

Energy partitioning and electron momentum distributions in intense laser-solid interactions

European Physical Journal D,; Vol. 71(2017)

Artikel i vetenskaplig tidskrift

Contemporary lasers are capable of reaching intensities equivalent to focusing all sunlight hitting the Earth down to the tip of a hair. At these intensities, lasers are capable of rapidly stripping atoms of their electrons and creating a plasma. Even more remarkable, these intensities are enough to push electrons to speeds near that of light within just one laser cycle, or to trigger the creation of antimatter.

Despite its scarcity on Earth, plasma is the most common state of matter in the universe, a majority of which is contained in stars. A plasma can be thought of as a charged fluid and is capable of interacting with both itself and its surroundings over large distances through self-generated electromagnetic fields. As a result, it can exhibit a wide range of complex phenomena, lending itself to be exploited for numerous unique applications. Perhaps most famous amongst these is the prospect of clean energy through controlled nuclear fusion, by mimicking the extreme environment of the sun. Because of the ability of high-intensity lasers to create such environments, they can be used for inertial confinement fusion and laboratory astrophysics.

Through their properties as charged media, plasmas are also capable of sustaining the immense acceleration gradients created by an intense laser field, making it possible to accelerate particles to high energies over very short, centimeter-scale, distances. At sufficiently high intensities, the field can also trigger the emission of high-energy photons and the creation of electron-positron pairs. High-intensity lasers have therefore become instrumental in creating compact particle accelerators and radiation sources, which themselves have a wide range of applications within materials, fundamental and medical sciences, and can as an example be used for various imaging techniques.

This thesis is concerned with the topics of particle acceleration and radiation generation using intense laser fields, focusing in particular on the acceleration of light ions, such as protons, and the generation of gamma radiation. Using state-of-the-art numerical codes, we have investigated a novel ion acceleration scheme allowing for a greater control over the acceleration process as well as the use of optimally focused laser radiation promising an efficient generation of gamma radiation at both current and upcoming laser facilities.

Plasmabaserade kompakta jonkällor

Knut och Alice Wallenbergs Stiftelse, 2014-07-01 -- 2019-06-30.

Ämneskategorier

Acceleratorfysik och instrumentering

Atom- och molekylfysik och optik

Fusion, plasma och rymdfysik

ISBN

978-91-7905-198-3

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4665

Utgivare

Chalmers tekniska högskola

PJ-salen, Fysikgården 2, Chalmers

Opponent: Laurent Gremillet, CEA, Frankrike

Mer information

Senast uppdaterat

2019-11-08