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Oubrerie, Kosta. "Amélioration de l'efficacité des accélérateurs laser-plasma". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAE002.
Pełny tekst źródłaTo generate high energy electron beams, conventional accelerators use radio frequency waves to accelerate charged particles to relativistic speeds. However, the accelerating electric field produced is limited to a few tens of megavolts per metre, mainly due to a breakdown phenomenon. Very large facilities are therefore needed to reach sufficiently high energies. For example, the Stanford Linear Accelerator (SLAC), which is the world's longest linear accelerator, accelerates electrons up to 50 GeV over a distance of 3.2 km. Laser-Plasma Accelerators can produce electric fields exceeding 100 GV/m, that are about three orders of magnitude larger than those obtained by radiofrequency-cavity accelerators. They could thus allow for a drastic decrease of the size of accelerators for scientific, medical and industrial applications. Yet, several bottlenecks have to be solved before these applications can be really implemented. It is notably necessary to demonstrate the efficient production of high-quality, multi-GeV electron beams at a high-repetition rate.The doctoral project tackles this problem by exploring new methods for increasing the energy of the electron beams thanks to techniques that are compatibles with arbitrarily high laser powers and repetition rates and that can be combined with controlled injection methods. Indeed, high energy or controlled injection electron beams have been obtained separately during the last fifteen years, but never combined. This thesis presents the work carried out on the guiding techniques as well as on the electron injection techniques which allowed to obtain experimentally good quality beams at high energies. This work was done in particular through the optimisation of a new optic designed at the Laboratoire d'Optique Appliquée, the axiparabola, as well as the development of gas jets specific to laser-plasma acceleration
Bocoum, Maïmouna. "Harmonic and electron generation from laser-driven plasma mirrors". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX023/document.
Pełny tekst źródłaThe experimental work presented in this manuscript focuses on the non-linear response of plasma mirrors when driven by a sub-relativistic (~10^18 W/cm^2) ultra-short (~30fs) laser pulse. In particular, we studied the generation of attosecond pulses (1as=10^(-18) s) and electron beams from plasma mirror generated in controlled pump-probe experiment. One first important result exposed in this manuscript is the experimental observation of the anticorrelated emission behavior between high-order harmonics and electron beams with respect to plasma scale length. The second important result is the presentation of the « spatial domain interferometry » (SDI) diagnostic, developed during this PhD to measure the plasma expansion in vacuum. Finally, we will discuss the implementation of phase retrieval algorithms for both spatial and temporal phase reconstructions.From a more general point of view, we replace this PhD in its historical context. We hope to convince the reader that through laser-plasma mirror interaction schemes, we could tomorrow conceive cost-efficient X-UV and energetic electron sources with unprecedented temporal resolutions
Mollica, Florian. "Interaction laser-plasma ultra-intense à densité proche-critique pour l'accélération d'ions". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX058/document.
Pełny tekst źródłaInteraction of ultra-intense, ultra-short laser with matter gives rise to a wealth of phenomena, due to the coupling between the electromagnetic field and the plasma. The non-linear coupling excites collective plasma processes able to sustain intense electric fields up to 1TV/m. This property spurred early interest in laser accelerator as compact, next-generation source of accelerated electrons and ions. Laser-driven ion source of several MeV was demonstrated in early 2000 an various mechanisms had been suggest to improve the their properties. These first ion sources have been obtained on solid targets, called “overdense”. Target innovation has driven the improvement of these sources. In the continuity of this dynamic, new gaseous targets had been proposed in order to relax the constraints that solid targets impose on laser contrast and repetition rate. Recent experimental demonstrations of monoenergetic ion acceleration in gas renew the interest in such targets, called under-dense or near-critical because of their intermediate densities. At near-critical density the laser can propagate, but undergoes significant absorbtion, giving rise to the accelerating structures of plasma shocks and magnetic vortex.The work presented in this thesis is an experimental exploration of the plasma conditions required to drive ion acceleration in gaseous near-critical target. For the first time, these regimes are explored with an ultra-intense, femtosecond laser of 150TW. A part of this work has been dedicated to the design of an innovative gas target, suited for plasma density and gradient constraints set by these regimes. Then the experimental works describe laser propagation and electron acceleration in near-critical targets. Finally the last part report the efficient production of an atomic beam from a laser-driven ion source
Leblanc, Adrien. "Miroirs et réseaux plasmas en champs lasers ultra-intenses : génération d’harmoniques d’ordre élevé et de faisceaux d’électrons relativistes". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS384/document.
Pełny tekst źródłaWhen focusing an ultra-intense femtosecond laser pulse [I>10¹⁶W/cm²] onto a solid target, this target is ionized at the very beginning of the laser pulse. The resulting dense plasma then reflects the laser in the specular direction: it is a plasma mirror. The ultra-intense laser field can accelerate electrons within the plasma at relativistic speeds. Some are ejected towards the vacuum and these plasma mirrors are therefore sources of relativistic electron beams. Moreover, at each optical cycle they radiate in the form of extreme ultraviolet light, resulting in the generation of high-order harmonics of the laser frequency (HHG). The objective of this PhD is to understand laser-plasma interaction though the characterization of high-order harmonics and relativistic electron beams generated from plasma mirrors. The first part deals with harmonic beam measurement. Due to the extreme physical conditions during the interaction, detection can only be performed at macroscopic distance from target. Thus, the characterization of the harmonic beams’ angular properties (carried out as a function of interaction conditions in previous works) only provides partial information on the interaction itself. A technique of coherent diffraction imaging, named ptychography, which consists of diffracting a probe onto an object, is transposed to HHG on plasma mirrors by optically micro-structuring the plasma on a target surface. Harmonic fields are then reconstructed spatially in amplitude and phase directly in the target plane. Thanks to this measurement in different interaction conditions, previously developed theoretical analytical models in non-relativistic regime [I<10¹⁸W/cm²] and relativistic regime [I>10¹⁸W/cm²] are experimentally validated. The second part of the PhD is dedicated to the experimental characterization of angular and spectral properties of relativistic electron beams. A theoretical and numerical study shows that this constitutes the first clear observation of vacuum laser acceleration (VLA). Finally, a simultaneous study of harmonic and electron signals highlights a strong correlation between both processes in the relativistic regime
Keston, David Arthur. "Bernstein modes in weakly relativistic e'-e'+ plasma". Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264260.
Pełny tekst źródłaDéchard, Jérémy. "Sources térahertz produites par des impulsions laser ultra-intenses". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS358/document.
Pełny tekst źródłaFemtosecond laser pulses trigger extreme nonlinear events inmatter, leading to intense secondary radiations spanning the frequency rangesfrom terahertz (THz) to X and gamma-rays.This work is dedicated to the theoretical and numerical study of THz radiationgenerated by laser-driven plasmas. Despite the inherent difficulty in accessingthe THz spectral window (0.1-100 THz), many coming applications use theability of THz frequencies to probe matter (spectroscopy, medicine, materialscience). Laser-driven THz sources appear well-suited to provide simultaneouslyan energetic and broadband signal compared to other conventional devices. Ourgoal is to investigate previously little explored interaction regimes in orderto optimize the laser-to-THz conversion efficiency.Starting from classical interactions in gases, we validate a unidirectionalpropagation model accounting for THz pulse generation, which we compare to theexact solution of Maxwell's equations. We next increase the laser intensityabove the relativistic threshold in order to trigger a nonlinear plasma wave inthe laser wake, accelerating electrons to a few hundreds of MeV. We show thatthe standard photocurrent mechanisms is overtaken by coherent transitionradiation induced by wakefield-accelerated electron bunch. Next, successivestudies reveal the robustness of this latter process over a wide range of plasmaparameters. We also demonstrate the relevance of long laser wavelengths inaugmenting THz pulse generation through the ionization-induced pressure thatincreases the laser ponderomotive force. Finally, THz emission from laser-solidinteraction is examined in the context of ultra-thin targets, shedding light onthe different processes involved
Touati, Michaël. "Fast Electron Transport Study for Inertial Confinement Fusion". Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0076/document.
Pełny tekst źródłaA new hybrid reduced model for relativistic electron beam transport in solids and dense plasmas is presented. It is based on the two first angular moments of the relativistic kinetic equation completed with the Minerbo maximum angular entropy closure. It takes into account collective effects with the self-generated electromagnetic fields as well as collisional effects with the slowing down of the elec- trons in collisions with plasmons, bound and free electrons and their angular scattering on both ions and electrons. This model allows for fast computations of relativistic electron beam transport while describing the kinetic distribution function evolution. Despite the loss of information concerning the angular distribution of the electron beam, the model reproduces analytical estimates in the academic case of a collimated and monoenergetic electron beam propagating through a warm and dense Hydro- gen plasma and hybrid PIC simulation results in a realistic laser-generated electron beam transport in a solid target. The model is applied to the study of the emission of Kα photons in laser-solid experiments and to the generation of shock waves
Heissler, Patrick. "Relativistic laser plasma interaction". Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-146019.
Pełny tekst źródłaMARQUES, JEAN-RAPHAEL. "Creation de plasmas homogenes pour l'excitation d'ondes plasma relativistes par battement d'ondes laser". Paris 11, 1992. http://www.theses.fr/1992PA112260.
Pełny tekst źródłaAppel, Walter. "Proprietes d'equilibre d'un plasma faiblement relativiste". Lyon, École normale supérieure (sciences), 1997. http://www.theses.fr/1997ENSL0051.
Pełny tekst źródłaVincenti, Henri Paul. "Génération d'impulsions attosecondes sur miroir plasma relativiste". Phd thesis, Ecole Polytechnique X, 2012. http://pastel.archives-ouvertes.fr/pastel-00787281.
Pełny tekst źródłaVincenti, Henri. "Génération d'impulsions attosecondes sur miroir plasma relativiste". Palaiseau, Ecole polytechnique, 2012. https://pastel.hal.science/docs/00/78/72/81/PDF/manuscrit.pdf.
Pełny tekst źródłaWhen an ultra intense femtosecond laser ($$I>10^{16}W. Cm^{-2}$$) with high contrast is focused on a solid target, the laser field at focus is high enough to completely ionize the target surface during the rising edge of the laser pulse and form a plasma. This plasma is so dense (the electron density is of the order of hundred times the critical density) that it completely reflects the incident laser beam in the specular direction: this is the so-called " plasma mirror ". When laser intensity becomes very high, the non-linear response of the plasma mirror to the laser field periodically deforms the incident electric field leading to high harmonic generation in the reflected beam. In the temporal domain this harmonic spectrum is associated to a train of attosecond pulses. The goals of my PhD were to get a better comprehension of the properties of harmonic beams produced on plasma mirrors and design new methods to control theses properties, notably in order to produce isolated attosecond pulses instead of trains. Initially, we imagined and modeled the first realistic technique to generate isolated attosecond on plasma mirrors. This brand new approach is based on a totally new physical effect: "the attosecond lighthouse effect". Its principle consists in sending the attosecond pulses of the train in different directions and selects one of these pulses by putting a slit in the far field. Despites its simplicity, this technique is very general and applies to any high harmonic generation mechanisms. Moreover, the attosecond lighthouse effect has many other applications (e. G in metrology). In particular, it paves the way to attosecond pump-probe experiments. Then, we studied the spatial properties of these harmonics, whose control and characterization are crucial if one wants to use this source in future application experiments. For instance, we need to control very precisely the harmonic beam divergence in order to achieve the attosecond lighthouse effect and get isolated attosecond pulses. At very high intensities, the plasma mirror dents and gets curved by the inhomogeneous radiation pressure of the laser field at focus. The plasma mirror surface thus acts as a curved surface, which focuses the harmonic beam in front of the target and fixes its spatial properties. We developed a fully analytical and predictive model for the surface deformation, thanks to which we are now able to calculate very easily the spatial properties of the generated harmonic beams. We validated this model through hundreds of 1D and 2D PIC simulations
Chopineau, Ludovic. "Physique attoseconde relativiste sur miroirs plasmas". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS132/document.
Pełny tekst źródłaWhen an ultra-intense femtosecond laser beam [Iʟ > 10¹⁶ W/cm²] is focused on a solid target, the surface becomes completely ionized during the first optical cycles of the laser pulse. Due to their solid-like density and to their limited expansion into the vacuum such plasmas specularly reflect these pulses, just like ordinary mirrors do for low intensity. These plasmas are now used in many scientific applications like particle acceleration by laser light as well as high-order harmonic generation, associated to a train of attosecond pulses in the time domain. Nevertheless, to favor these emissions of light or particle, the energy transfert between the incident field and the dense plasma is crucial. The aim of this thesis is to better understand these interactions through the characterization of high-order harmonics and relativistic electron beams generated on plasma mirrors. We reported in this manuscript the first detailed experimental and numerical study of the coupling mechanisms involved between an ultra-intense laser light [Iʟ > 10¹⁸ W/cm²] and a dense plasma, and more specifically as a function of the gradient scale length Lg. These results enabled to identify two different regimes, clarifying some physical issues. Furthermore, beyond these fondamental aspects, the control of these sources is essential, particularly for futures pump-probe experiments or new spectroscopies. For that, several approaches have been studied to temporally and spatially shape these ultra-short light pulses, thus opening up new perspectives for these sources. We demonstrate in particular the generation of intense XUV vortex beam either by spatially shaping the incident IR field or the dense plasma created at the target surface as well as controlling the electron dynamics on the attosecond time scale with relativistic two-color waveforms. Finally, an innovative method based on in-situ ptychographic measurements has been developed to simultaneously characterize in time and space these ultrashort XUV light pulses, constituting one of the major challenges of the community
Miller, Evan. "Magnetogenesis through Relativistic Velocity Shear". Thesis, Dartmouth College, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10001975.
Pełny tekst źródłaMagnetic fields at all scales are prevalent in our universe. However, current cosmological models predict that initially the universe was bereft of large-scale fields. Standard magnetohydrodynamics (MHD) does not permit magnetogenesis; in the MHD Faraday’s law, the change in magnetic field B depends on B itself. Thus if B is initially zero, it will remain zero for all time. A more accurate physical model is needed to explain the origins of the galactic-scale magnetic fields observed today. In this thesis, I explore two velocity-driven mechanisms for magnetogenesis in 2-fluid plasma. The first is a novel kinematic ‘battery’ arising from convection of vorticity. A coupling between thermal and plasma oscillations, this non-relativistic mechanism can operate in flows that are incompressible, quasi-neutral and barotropic. The second mechanism results from inclusion of thermal effects in relativistic shear flow instabilities. In such flows, parallel perturbations are ubiquitously unstable at small scales, with growth rates of order with the plasma frequency over a defined range of parameter-space. Of these two processes, instabilities seem far more likely to account for galactic magnetic fields. Stable kinematic effects will, at best, be comparable to an ideal Biermann battery, which is suspected to be orders of magnitude too weak to produce the observed galactic fields. On the other hand, instabilities grow until saturation is reached, a topic that has yet to be explored in detail on cosmological scales. In addition to investigating these magnetogenesis sources, I derive a general dispersion relation for three dimensional, warm, two species plasma with discontinuous shear flow. The mathematics of relativistic plasma, sheared-flow instability and the Biermann battery are also discussed.
Bourgeois, Pierre-Louis. "Modélisation de sources X générées par interaction laser-plasma en régime relativiste". Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX073.
Pełny tekst źródłaWhen an ultra-short ultra-intense laser impulsion propagates through a low density gas jet, a plasma is created and a bunch of electrons can be accelerated through laser wakefield acceleration to Gev energies in only a few centimetres. Those accelerated electrons then emit what is called Betatron radiation: a highly focused X-ray source with extremely good spatial and temporal properties, which has a lot of possible applications including ultra-high resolution imaging.In this thesis, we investigate possible improvements to one of the main numerical tools used to simulate those phenomenons: the Particle-In-Cell codes (CALDER). We have especially studied a numerical artefact called the numerical Cherenkov radiation, that occurs when relativistic particles move at speeds aproaching the speed of light in a vaccuum.We show that this artefact has a negative impact on the behaviour of the accelerated electron beam, especially on its transverse motion, which leads to important errors on the betatron radiation calculated using PIC simulations.We then introduce a new approach to mitigate the impact of this numerical Cherenkov radiation on laser wakefield acceleration simulation with a simple modification of the electromagnetic field interpolation method used in PIC codes. The results obtained with this new technique show a meaningful improvement on the electron motion wich becomes close to the theoretically expected behaviour.We then explore other possible applications for this new technique, notably improving the modelization of betatron sources, vacuum laser acceleration or direct laser acceleration.The improvement of the computation of the particles transverse motion thanks to this new method leads to more accurate results but also enables us to study physical phenomenon with subtle effects that would otherwise be hidden among the numerical noise of the simulation
Jaroschek, Claus. "Critical Kinetic Plasma Processes In Relativistic Astrophysics". Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-46601.
Pełny tekst źródłaStreeter, Matthew. "Ultrafast dynamics of relativistic laser plasma interactions". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24854.
Pełny tekst źródłaThaury, Cédric. "Génération d'harmoniques d'ordres élevés sur miroir plasma". Phd thesis, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00335261.
Pełny tekst źródłaAu cours de cette thèse, nous avons prouvé que lorsque l'éclairement laser est de l'ordre de $10^{19}Wcm^{-2}$, deux mécanismes peuvent contribuer à la génération d'harmoniques d'ordres élevés sur miroir plasma : l'émission cohérente de sillage et l'émission relativiste. Ces deux mécanismes ont été étudiés à la fois théoriquement et expérimentalement.
Nous avons ainsi montré que, grâce à des propriétés très différentes, les harmoniques générées par ces deux processus peuvent être distinguées expérimentalement, sans ambiguïté. Nous nous sommes ensuite intéressés aux propriétés de phase spectrales et spatiales des harmoniques. Enfin, nous avons illustré comment exploiter la cohérence des mécanismes de génération pour obtenir des informations sur la dynamique électronique du plasma.
Moreau, Julien. "Interaction d’une impulsion laser intense avec un plasma sous dense dans le régime relativiste". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0042/document.
Pełny tekst źródłaThe laser-accelerated ions draw an increasing interest due to their potential applications and to their unique properties. This manuscript presents a study of the interaction between a relativistic intense laser pulse and a low density plasma. In this regime, the plasma is transparent to the laser pulse and electrons oscillate with relativistic velocities in the field of the incident wave. These conditions make the transfer of the laser pulse energy to the plasma efficient, and therefore are interesting for the ion acceleration. This regime generates also electromagnetic and acoustic solitons whose formation mechanisms and properties need to be better understood. We carry out a detailed analysis of Particle-In-Cell simulations (performed with the code OCEAN) of interaction of an intense laser pulse with a low density plasma.We show that the stimulated Raman scattering (SRS) is the main mechanism responsible for the absorption of laser energy in plasma. This process is very efficient : it leads to the transfer of 70 % of the laser pulse energy to electrons. This instability occurs in plasmas with a density larger than the quarter critical one due to the decrease of the electron plasma frequency and develops in a very short time scale. It leads to an homogeneous electron heating all along the distance of propagation of the laser pulse through the plasma. The ions are efficiently accelerated at the plasma edges and can get nearly 30%of the initial laser energy. This study is accompanied by a simple analytical model which is able to predict and so optimize the laser backscattering fraction due to the development of the SRS instability. We also present a sequence of stages which lead to the formation of electromagnetic cavities. This analysis highlights the role of the modulationnal or Benjamin-Feir instability in the front of the laser pulse, which is split in a train of electromagnetic solitons. Our detailed study shows that these solitons excite plasmas waves in their wake, lose energy and are finally trapped in the plasma. They lead to the formation of density depressions (cavities) which may trap the electromagnetic fields produced in the plasma (by the SRS instability, for example). These structures may survive for a long time thanks to an equilibrium of the trapped field radiation pressure and the electronic kinetic pressure at their borders. These cavities absorb an significant part of the laser energy but only a part of it is trapped inside. The remaining part is invested in the cavity expansion, generation of acoustic solitons and acceleration of charged particles
MAGNEVILLE, ALAIN. "Propagation d'ondes plasma dans des sytemes chauds relativistes de type faisceau-plasma". Paris 11, 1990. http://www.theses.fr/1990PA112017.
Pełny tekst źródłaBouchard, Guillaume. "Étude théorique et numérique de la génération d’harmoniques XUV à l’aide de lasers ultra-intenses sur feuilles minces". Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS037.
Pełny tekst źródłaWhen focusing an ultra-intense femtosecond laser pulse (Iλ0² > 10¹⁶ W.cm⁻ ²) on to a solid, the incident laser field is sufficiently high to ionise almost entirely the target at the very beginning of the pulse.Thus the most part of the laser field is reflected in the specular direction by the overdense plasma created until then : This is what we call a plasma mirror. The electrons, accelerated by the ultra-intense laser field ,are pulled out of the plasma with speeds which are almost equal to the speed of light c. For each laser period, electrons are the sources of a high-frequency radiation that can extend to the Extreme Ultra Violetor X domains. This periodicity in the generation process leads to the emergence of a harmonic spectrum of the laser frequency ω₀. Eventually, electrons are pushed back into the plasma with speeds always very close to c. Even though mechanisms of the XUV radiation are well known in the specular direction today, too few studies were conducted to understand generations process in the transmitted direction.The objective of this PhD thesis is to deepen understanding the laser-plasma interaction for the case where the target thickness is of the wavelength order. In particular, we will study the role of relativistic electronsjets in the forward radiation, when they fly across the target rear side.The first part of this manuscript will essentially deal with the already well-known mechanisms which explain the radiation in the specular direction. We can wonder to what extent these models are not sufficient to describe the forward radiation, in the transmitted direction.The second part of this manuscript deal with FDTD methods (Finite Difference Time Domain) in use in the "Particle-in-Cell" codes, especially two numerical effects induced by these methods potentially harmful for simulations in order to achieve physical results with meaning : Numerical dispersion and Numerical Cherenkov Instabilities. We will try to make an improvement to the algorithms in order to mitigate these two annoying effects. Eventually, we will identify a new coherent XUV radiation mechanism : The coherent plasma bremsstrahlung or coherent plasma braking radiation. When electrons leave the plasma, a several TV space-charge field appear on the target rear side. This braking longitudinal field accelerate electrons jets transversally which was created by next optical cycles. These jets radiate intenselight pulses of hundreds attoseconds
Albert, Felicie. "Rayonnement synchrotron base sur l'interaction laser-plasma en regime relativiste". Phd thesis, Ecole Polytechnique X, 2007. http://pastel.archives-ouvertes.fr/pastel-00004556.
Pełny tekst źródłaGustas, Dominykas. "High-repetition-rate relativistic electron acceleration in plasma wakefields driven by few-cycle laser pulses". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX118/document.
Pełny tekst źródłaContinuing progress in laser technology has enabled dramatic advances in laser wakefield acceleration (LWFA), a technique that permits driving particles by electric fields three orders of magnitude higher than in conventional radio-frequency accelerators. Due to significantly reduced space charge and velocity dispersion effects, the resultant relativistic electron bunches have also been identified as a candidate tool to achieve unprecedented sub-10 fs temporal resolution in ultrafast electron diffraction (UED) experiments. High repetition rate operation is desirable to improve data collection statistics and thus washout shot-to-shot charge fluctuations inherent to plasma accelerators. It is well known that high-quality electron beams can be achieved in the blowout, or "bubble" regime, which is at present regularly accessed with ≈ 30 fs Joule-class lasers that can perform up to few shots per second. Our group on the contraryutilized a cutting edge laser system producing few-mJ pulses compressed nearly to a single optical cycle (3.4 fs) to demonstrate for the first time an MeV-grade particle accelerator with properties characteristic to the blowout regime operating at 1 kHz repetition rate. We further investigate the plasma density profile and exact laser pulse waveform effects on the source output, and show that using special gas microjets a charge of tens of pC/shot can be achieved. We expect this technique to lead to a generation of highly accessible and robust instruments for the scientific community to conduct UED experiments or to be used for other applications. This work also serves to expand our knowledge on the scalability of laser-plasma acceleration
Fuchs, Julien. "Interaction laser-plasma en régime relativiste dans le contexte de l'allumeur rapide. Propagation dans les plasmas sous-critiques et sur-critiques". Paris 11, 1998. http://www.theses.fr/1998PA112169.
Pełny tekst źródłaBöhle, Frederik. "Near-single-cycle laser for driving relativistic plasma mirrors at kHz repetition rate - development and application". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX116/document.
Pełny tekst źródłaVery short light pulses allow us to resolve ultrafast processes in molecules, atoms and condensed matter. This started with the advent of Femtochemistry, for which Ahmed Zewail received the Novel Prize in Chemistry in 1999. Ever since, researcher have been trying to push the temporal resolution further and we have now reached attosecond pulse durations. Their generation, however, remains very challenging and various different generation mechanisms are the topic of heated research around the world.Our group focuses on attosecond pulse generation and ultrashort electron bunch acceleration on solid targets. In particular, this thesis deals with the upgrade of a high intensity, high contrast, kHz, femtosecond laser chain to reach the relativistic interaction regime on solid targets. Few cycle driving laser pulses should allow the generation of intense isolated attosecond pulses. A requirement to perform true attosecond pump-probe exeriments.To achive this, a HCF postcompression scheme has been conceived and implemented to shorten the duration of a traditional laser amplifier. With this a peak intensity of 1TW was achieved with near-single-cycle pulse duration. For controlled experiments, a vacuum beamline was developed and implemented to accurately control the laser and plasma conditions on target.During the second part of this thesis, this laser chain was put in action to drive relativistic harmonic generation on solid targets. It was the first time ever that this has been achieved at 1 kHz. By CEP gating the few-cycle-pulses, single attosecond pulses were generated. This conclusion has been supported by numerical simulations. Additionally a new regime to accelerate electron bunches on soft gradients has been detected
Parachoniak, Ronald D. "Numerical experiments using an electrostatic, relativistic plasma simulation code". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26023.
Pełny tekst źródłaScience, Faculty of
Physics and Astronomy, Department of
Graduate
Mangles, Stuart Peter David. "Measurements of relativistic electrons from intense laser-plasma interactions". Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417730.
Pełny tekst źródłaGallacher, Jordan G. "Relativistic electrons and radiation from intense laser-plasma sources". Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=15481.
Pełny tekst źródłaQin, GuangYou. "Penetrating probes in relativistic heavy ion collisions". Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115878.
Pełny tekst źródłaFaure, Jérôme. "Accélération de particules par interaction laser-plasma dans le régime relativiste". Habilitation à diriger des recherches, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00404354.
Pełny tekst źródłaAl-Naseri, Haidar. "Quantum kinetic relativistic theory of linearized waves in magnetized plasmas". Thesis, Umeå universitet, Institutionen för fysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-150292.
Pełny tekst źródłaKrivenski, Vladimir. "Étude cinétique relativiste du chauffage et de la génération de courant cyclotroniques électroniques dans un tokamak". Nancy 1, 1988. http://www.theses.fr/1988NAN10281.
Pełny tekst źródłaCapdessus, Rémi. "Dynamique d'un plasma non collisionnel interagissant avec une impulsion laser ultra-intense". Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR15268/document.
Pełny tekst źródłaRésumé en anglais
Jäckel, Oliver. "Characterisation of ion acceleration with relativistic laser-plasmas". Tönning Lübeck Marburg Der Andere Verl, 2009. http://d-nb.info/995862729/04.
Pełny tekst źródłaCantono, Giada. "Relativistic Plasmonics for Ultra-Short Radiation Sources". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS353/document.
Pełny tekst źródłaPlasmonics studies how the electromagnetic radiation couples with the collective oscillations of the electrons within a medium. Surface plasmons (SPs), in particular, have a well-established role in the development of forefront photonic devices, as they allow for strong enhancement of the local EM field over sub-micrometric dimensions. Promoting the SP excitation to the high-field regime, where the electrons quiver at relativistic velocities, would open stimulating perspectives for the both the manipulation of ultra-intense laser light and the development of energetic, short radiation sources. Indeed, the excitation of resonant plasma modes is a possible strategy to efficiently deliver the energy of a high-power laser to a solid target, this being among the current challenges in the physics of highly-intense laser-matter interaction. Gathering these topics, this thesis demonstrates the opportunity of resonant surface plasmon excitation at ultra-high laser intensities by studying how such waves accelerate bunches of relativistic electrons along the target surface and how they enhance the generation of high-order harmonics of the laser frequency. Both these processes have been investigated with numerous experiments and extensive numerical simulations. Adopting a standard configuration from classical plasmonics, SPs are excited on solid, wavelength-scale grating targets. In their presence, both electron and harmonic emissions exhibit remarkable features that support the conception of practical applications. Putting aside some major technical and conceptual issues discouraging the applicability of plasmonic effects in the high-field regime, these results are expected to mark new promises to the exploration of Relativistic Plasmonics
Snyder, Joseph Clinton. "Leveraging Microscience to Manipulate Laser-Plasma Interactions at Relativistic Intensities". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483626346580096.
Pełny tekst źródłaNagel, Sabrina Roswitha. "Studies of Electron Acceleration Mechanisms in Relativistic Laser-Plasma Interactions". Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/4639.
Pełny tekst źródłaIgnesti, Alessandro <1992>. "Interplay between relativistic and thermal plasma in relaxed galaxy clusters". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9827/1/PhD_Thesis_Ignesti_revised.pdf.
Pełny tekst źródłaMetens, Thierry. "Théorie cinétique du transport dans un plasma relativiste. Application au current drive". Doctoral thesis, Universite Libre de Bruxelles, 1989. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/213251.
Pełny tekst źródłaWen, Haibao. "Aspects of high field theory in relativistic plasmas". Thesis, Lancaster University, 2012. http://eprints.lancs.ac.uk/76598/.
Pełny tekst źródłaBindslev, Henrik. "On the theory of Thomson scattering and reflectometry in a relativistic magnetized plasma". Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314912.
Pełny tekst źródłaJanson, Oskar. "Gravitational Wave Interaction in a Vlasov Plasma". Thesis, Umeå universitet, Institutionen för fysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-72776.
Pełny tekst źródłaGravitationsvågor förutses i Einsteins allmänna relativitetsteori och har så här långt endast blivit indirekt detekterade. Den första direkta detektionen är dock bara en tidsfråga och observatorier runtom i världen arbetar hårt för att lyckas med den. Då gravitationsvågor väl är detekterade sägs de ha stor potential inom astronomi. För att man ska kunna tolka mätdata från gravitationsvågor behöver man veta hur vågen beter sig i propagationsmediet. Av den anledningen är syftet med detta examensarbete att undersöka hur gravitationsvågor beter sig i ett magnetiserat plasma. Med hjälp av en modell för kinetisk plasma, Einsteins fältekvationer och tetradformalism härleds en allmän lösning för en gravitationsvåg som propagerar i en magnetiserad plasma fram. Lösningen används därefter för att hitta dispersionsrelationen för gravitationsvågen givet två specialfall: fallet för Alfvénresonans och fallet för cyklotronresonens. Alfvénfallet är redan studerat i tidigare litteratur och resultatet man hittar visar sig stämma överens med det tidigare funna resultatet som säger att det inte har en märkbar påverkan på vågen. Cyklotronresonansfallet är nytt och valdes eftersom att det kan förstärka de effekter som partiklarna har på gravitationsvågen. De båda specialfallen studeras närmare med avseende på detektion av en dispersion inducerad av mediet. Påverkan på gravitationsvågens propagation sluts dock till att vara för liten för att den ska bli uppmätt i de undersökta fallen.
Link, Anthony John. "Specular Reflectivity and Suprathermal Electron Measurements from Relativistic Laser Plasma Interactions". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1268149986.
Pełny tekst źródłaAugst, Nathalie. "Etude théorique et expérimentale d'un klystron relativiste à effet de porte". Palaiseau, Ecole polytechnique, 1992. http://www.theses.fr/1992EPXX0010.
Pełny tekst źródłaMelzani, Mickaël. "Reconnexion magnétique non-collisionelle dans les plasmas relativistes et simulations particle-in-cell". Thesis, Lyon, École normale supérieure, 2014. http://www.theses.fr/2014ENSL0946/document.
Pełny tekst źródłaThe purpose of this thesis is to study magnetic reconnection in collisionless and relativistic plasmas. Such plasmas can be encountered in various astrophysical objects (microquasars, AGNs, GRBs...), where reconnection could explain high-energy particle and photon production, plasma heating, or transient large-scale outflows. However, a first principle understanding of reconnection is still lacking, especially in relativistic ion-electron plasmas. We first present the basis of reconnection physics. We derive results relevant to relativistic plasma physics, including properties of the Maxwell-Jüttner distribution. Then, we provide a detailed study of our numerical tool, particle-in-cell simulations (PIC). The fact that the real plasma contains far less particles than the PIC plasma has important consequences concerning relaxation times or noise, that we describe. Finally, we study relativistic reconnection in ion-electron plasmas with PIC simulations. We stress outstanding properties: Ohm's law (dominated by bulk inertia), structure of the diffusion zone, energy content of the outflows (thermally dominated), reconnection rate (and its relativistic normalization). Ions and electrons produce power law distributions, with indexes that depend on the inflow Alfvén speed and on the magnetization of the corresponding species. They can be harder than those produced by collisionless shocks. Also, ions can get more or less energy than the electrons, depending on the guide field strength. These results provide a solid ground for astrophysical models that, up to now, assumed with no prior justification the existence of such distributions or of such ion/electron energy repartition
Kemp, Gregory Elijah. "Specular Reflectivity and Hot-Electron Generation in High-Contrast Relativistic Laser-Plasma Interactions". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1375386740.
Pełny tekst źródłaYaseen, Mohammad. "DESCRIBING THE DYNAMICS OF THE QUARK-GLUON PLASMA USING RELATIVISTIC VISCOUS HYDRODYNAMICS". Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1469679328.
Pełny tekst źródłaManclossi, Mauro. "Interaction laser plasma dans le régime relativiste : Application à la production de sources ultrabrèves de particules énergétiques". Phd thesis, Ecole Polytechnique X, 2006. http://pastel.archives-ouvertes.fr/pastel-00002571.
Pełny tekst źródłaOwen, J. A. "Effects of the relativistic correction to the electron mass on electron cyclotron current drive". Thesis, University of St Andrews, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370602.
Pełny tekst źródłaChen, Cliff D. (Cliff Ding Yu). "Spectrum and conversion efficiency measurements of suprathermal electrons from relativistic laser plasma interactions". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53213.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (p. 147-156).
Fast Ignition is an alternative scheme for Inertial Confinement Fusion (ICF) that uses a petawatt laser to ignite a hot spot in precompressed fuel. The laser delivers its energy into relativistic electrons at the critical surface of the blowoff plasma. These electrons must propagate to the fuel core and deliver their energy to a hot spot. Electrons of energies between 1 and 3 MeV have the appropriate range for efficient energy deposition. This thesis experimentally explores the coupling efficiency and spectrum of the laser produced electrons. The experiments make use of Bremsstrahlung and K-shell emission from planar foil targets to infer the electron distribution produced in the laser-plasma interaction. This thesis describes the development of a filter stack Bremsstrahlung spectrometer with differential sensitivity up to 500 keV. The spectrometer is used with a single photon counting camera for measuring K[alpha] emission in experiments on the Titan laser (1.06 [mu]m, 150 J, 0.7 ps) at Lawrence Livermore National Laboratories. The Bremsstrahlung and K-shell emission from 1 mm3 planar targets irradiated with intensities from 3x1018-8x1019 W/cm2 were measured. The target emission is modeled using the Monte Carlo code Integrated Tiger Series 3.0 in order to unfold the electron spectrum from the x-ray measurements. Conversion efficiencies into 1-3 MeV electrons of 12-28% were inferred, representing 35-60% total conversion efficiencies. Laser diagnostics were used to characterize the laser focal spot and pulselength in order to provide proper comparisons to intensity scaling laws.
(cont.) Comparisons to scaling laws show that the electron spectrum is colder than the laser ponderomotive potential derived from the peak intensity. For intensities above 2 x 1019 W/cm2, the spectrum is slightly hotter than widely used empirical scalings. More accurate comparisons to ponderomotive scaling using a synthetic energy spectra generated from the intensity distribution of the focal spot imply slope temperatures less than the ponderomotive potential, but is within the range of a correction due to the neglect of resistive transport effects. The impact of resistive transport effects were estimated using an analytic transport model and may lead to higher total conversion efficiencies but lower conversion efficiencies into 1-3 MeV electrons.
by Cliff D Chen.
Ph.D.