Dokument: High harmonic generation from relativistic plasma
| Titel: | High harmonic generation from relativistic plasma | |||||||
| Weiterer Titel: | Erzeugung von hohen Harmonischen in relativistischen Plasmen | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=8382 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20080714-112149-7 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Dipl.-Phys. Baeva, Teodora [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Pukhov, Alexander [Gutachter] Prof. Dr. Spatschek, Karl-Heinz [Gutachter] | |||||||
| Stichwörter: | coherent x-rays, harmonic generation, relativistic plasma, laser-matter interaction, ultra-short pulses | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 530 Physik | |||||||
| Beschreibung: | The theory of relativistic spikes developed in this Thesis presents a new physical mechanism of high harmonic generation at the boundary of an overdense relativistic plasma. This is the first time, the laser-plasma theory has proposed both a physical mechanism and an analytical approach that predict the universal power-law decay and the scaling for the roll-over of the high harmonic spectrum generated in relativistic laser--plasma interaction. The unique feature of this power-law spectrum is the high
roll-over frequency. The harmonic spectrum depends neither on the laser pulse shape, nor on the details of the laser-plasma interaction. These theoretical advances of the theory of relativistic spikes have been confirmed experimentally. The theoretical foundation of this work is sufficient to demonstrate the robustness of the high harmonic generation process, which prevails in practical experiments where various imperfections occur. Indeed, this Thesis shows that the whole plasma skin layer is in a coherent state, thereby enabling it to generate high harmonics with wavelengths that are much shorter than both the size of the surface roughness and the skin layer thickness. This fact has made possible the experimental observation of high harmonics of unprecedentedly high frequencies and wavelengths of a few Angstroems, in agreement with the theoretical predictions. The relativistically invariant apparent reflection point formalism, developed in this work, encapsulates the features of ultra-relativistic laser-plasma interaction relevant to the generation of high energy coherent photons. This formalism puts the analytical theory of high harmonic generation on a firm mathematical footing and states that the relativistic gamma-factor of the apparent reflection point has sharp ultra-relativistic spikes. These spikes originate from the electron motion inside the skin layer and are due to the zeros of the vector potential. Each ultra-relativistic spike causes the generation of an electromagnetic shock wave, which contains high harmonics. A mechanism to control the generation of high harmonics, to produce sub-attosecond pulses and to isolate single ultra-short pulses is proposed. Consequently, the new physical phenomenon of relativistic gamma-spikes developing in relativistic laser-plasma interaction provides a robust mechanism to generate coherent radiation and even isolated ultra-short X-ray pulses in the soft and hard X-ray regions, making possible the development of X-ray time-resolved metrology. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Physik » Theoretische Physik | |||||||
| Dokument erstellt am: | 08.07.2008 | |||||||
| Dateien geändert am: | 08.07.2008 | |||||||
| Promotionsantrag am: | 19.05.2008 | |||||||
| Datum der Promotion: | 30.06.2008 |
