Download or read book Characterization of Laser driven Proton Acceleration with Contrast enhanced Laser Pulses written by Georg Becker and published by . This book was released on 2021* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, various novel aspects of laser-driven ion acceleration with contrast-enhanced laser pulses have been characterized. The maximum ion energies' dependence on the pulse energy and the foil thickness was investigated in a campaign at the POLARIS laser using a plasma mirror for contrast enhancement. The steepest increase of the ion energies depending on the pulse energy was measured for a 5 nm thin foil and linear polarization. Above a certain pulse energy, the onset of the foil's transparency correlated with a stop of the ion energies' increase. Consequently, additional enhancements of the temporal intensity contrast (TIC) and higher laser pulse intensities are required to exploit ion acceleration with such thin foils. The ring-like beam profile formed by protons with low kinetic energy, which originated from submicron thick plastic foils, was characterized. Simulations support the explanation that such structures are a consequence of the proton density's spatial distribution during the acceleration with the target normal sheath acceleration mechanism (TNSA). These findings deepen the understanding of ion acceleration with thin foils and may help to distinguish features of other acceleration mechanisms in the beam profile from those attributed to TNSA. In an experiment with water microdroplets, the effects of the laser's TIC and the incidence angle in the polarization plane were investigated. It was found that both parameters have a significant influence on the kinetic energy of the accelerated protons. An optical probe laser was used to observe the plasma expansion on a picosecond timescale. A correlation between the expansion and the maximum proton energy was found. The proton beam profile exhibited a reproducible net-like pattern depending on the irradiation geometry as well. The results show that the use of microdroplets irradiated with frequency-doubled laser pulses and optically probed gives new insights into laser-plasma interaction.

Download or read book Laser driven Proton Acceleration with Two Ultrashort Laser Pulses written by Jürgen Böker and published by . This book was released on 2015 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser driven Proton Beams written by Ceri M. Brenner and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports on investigations of proton acceleration driven by the interaction of short, intense laser pulses with thin, solid targets. Laser-driven plasma interactions are used to establish accelerating quasi-electrostatic field gradients, on the rear surface of the target, that are orders of magnitude higher than the current limit of conventional, radio-frequency-based accelerator technology. The resulting high energy (multi-MeV) proton beams are highly laminar, have ultra-low emittance, and the inherently broad energy spectrum is particularly effective for use in proton imaging, heating and transmutation applications. This thesis reports on a series of investigations carried out to explore routes towards control of the spectral properties of laser-driven proton sources and optimisation of laser-to-proton energy conversion efficiency. The dependence of laser accelerated proton beam properties on laser energy and focal spot size in the interaction of an intense laser pulse with an ultra-thin foil is explored at laser intensities of 1016-1018 W/cm2. The results indicate that whilst the maximum proton energy is dependent on both these laser pulse parameters, the total number of protons accelerated is primarily related to the laser pulse energy. A modification to current analytical models of the proton acceleration, to take account of lateral transport of electrons on the target rear surface, is suggested to account for the experimental findings. The thesis also reports on an investigation of optical control of laser-driven proton acceleration, in which two relativistically intense laser pulses, narrowly separated in time, are used. This novel approach is shown to deliver a significant enhancement in the coupling of laser energy to medium energy (5-30 MeV) protons, compared to single pulse irradiation. The 'double-pulse' mechanism of proton acceleration is investigated in combination with thin targets, for which refluxing of hot electrons between the target surfaces can lead to optimal conditions for coupling laser drive energy into the proton beam. A high laser-to-proton conversion efficiency is measured when the delay between the pulses is optimised at 1 ps. The subsequent effect of double-pulse drive on the angular distribution of the proton beam is also explored for thick targets.

Download or read book Investigations of Field Dynamics in Laser Plasmas with Proton Imaging written by Thomas Sokollik and published by Springer Science & Business Media. This book was released on 2011-01-12 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-driven proton beams are still in their infancy but already have some outstanding attributes compared to those produced in conventional accelerators. One such attribute is the typically low beam emittance. This allows excellent resolution in imaging applications like proton radiography. This thesis describes a novel imaging technique - the proton streak camera - that the author developed and first used to measure both the spatial and temporal evolution of ultra-strong electrical fields in laser-driven plasmas. Such investigations are of paramount importance for the understanding of laser-plasma interactions and, thus, for optimization of laser-driven particle acceleration. In particular, the present work investigated micrometer-sized spherical targets after laser irradiation. The confined geometry of plasmas and fields was found to influence the kinetic energy and spatial distribution of accelerated ions. This could be shown both in experimental radiography images and and in numerical simulations, one of which was selected for the cover page of Physical Review Letters.

Download or read book Investigation of Laser driven Particle Acceleration for the Development of Tunable Ion Sources for Applications in High Energy Density Science written by Raspberry Simpson and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the innovation of chirped pulse amplification by Donna Strickland and Gerard Morou in 1985, laser technology has evolved such that we can create short pulses of light (10−15 − 10−12 seconds) with high peak powers (1015 Watts) in small, focused spots (∼a few microns). A prolific area of research that has emerged over the last two decades is the use of these high-intensity lasers to drive particle beams. Possible applications of these particle sources include isotope production for medical applications, proton cancer therapy, and fusion energy schemes. This thesis focuses on laser-driven proton acceleration and adds to the existing foundation of work in the area by investigating new empirical relationships, conducting new measurements of the accelerating electric field responsible for laser-driven proton acceleration, and developing a new data analysis methodology using machine learning. This work first examines laser-driven proton acceleration in the multi-picosecond regime (>1ps) at laser intensities of 1017 - 1019 W/cm2. This is motivated by recent results on laser platforms like the National Ignition Facility-Advanced Radiographic Capability laser and the OMEGA-Extended Performance laser, which have demonstrated enhanced accelerated proton energies when compared to established scaling laws. A detailed scaling study was performed on the Titan laser, which provided the basis for a new analytical scaling presented in this thesis. In addition, high-repetition-rate (HRR) lasers that can operate at 1 Hz or faster are now coming online around the world, opening a myriad of opportunities for accelerating the rate of learning on laser-driven particle experiments. To unlock these applications, HRR diagnostics combined with real-time analysis tools must be developed to process experimental measurements and outputs at HRR. Towards this goal, this thes is presents a novel automated data analysis framework based on machine learning and proposes a new methodology based on representation learning to integrate heterogeneous data constrain parameters that are not directly measurable. Taken together, these thrusts enable a new preliminary framework for enhanced analysis of complex HRR experiments and a foundational step towards realizing the goal of tunable laser-driven particle sources.

Download or read book Laser Plasma Interactions written by Dino A. Jaroszynski and published by CRC Press. This book was released on 2009-03-27 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Solid Compendium of Advanced Diagnostic and Simulation ToolsExploring the most exciting and topical areas in this field, Laser-Plasma Interactions focuses on the interaction of intense laser radiation with plasma. After discussing the basic theory of the interaction of intense electromagnetic radiation fields with matter, the book covers three ap

Download or read book Coherence and Ultrashort Pulse Laser Emission written by F. J. Duarte and published by IntechOpen. This book was released on 2010-12-30 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this volume, recent contributions on coherence provide a useful perspective on the diversity of various coherent sources of emission and coherent related phenomena of current interest. These papers provide a preamble for a larger collection of contributions on ultrashort pulse laser generation and ultrashort pulse laser phenomena. Papers on ultrashort pulse phenomena include works on few cycle pulses, high-power generation, propagation in various media, to various applications of current interest. Undoubtedly, Coherence and Ultrashort Pulse Emission offers a rich and practical perspective on this rapidly evolving field.

Download or read book Efficient Laser driven Proton Acceleration in the Ultra short Pulse Regime written by Karl Zeil and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization and Optimization of Laser driven Ion Acceleration written by Kealan Naughton and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Power Laser Matter Interaction written by Peter Mulser and published by Springer Science & Business Media. This book was released on 2010-07-05 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction and handbook to high-power laser-matter interaction, laser generated plasma, nonlinear waves, particle acceleration, nonlinear optics, nonlinear dynamics, radiation transport, it provides a systematic review of the major results and developments of the past 25 years.

Download or read book Experimental Studies of Laser Driven Proton Acceleration from Ultrashort and Highly Intense Laser Pulse Interaction with Overdense Plasma written by Donghoon Kuk and published by . This book was released on 2014 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The generation of high current multi-MeV protons and ions by irradiation of short pulse high intense laser on an ultra-thin target has been observed and subjected great interest in recent. When ultra-thin overdense target is irradiated by focused ultraintense laser pulse, hot electrons are generated by various mechanisms and they generate energetic ion beams. In TNSA, a quasi-electrostatic field is produced on the target rear surface when the the laser pulse interacts with overdense target, driving hot electrons go torward the target rear surface. However, this mechanism results in a range of field gradients leading to a broad proton energy distribution typically. To overcome the issue, an alternative accelration mechanism has been presented to achieve the quasi-monoenergetic proton acceleration and the mechanism is called Radiation Pressure Acceleration. In the RPA, the radiation pressure push electrons into the target smoothly and setting up an electrostatic field by the laser pressure. In this thesis, we study two alternative experimental methods for the quasi-monoenergetic proton acceleration and find experimental feasibility of the presented methods from other research groups.

Download or read book High contrast laser driven monoenergetic proton beams and near critical density plasma diagnosis written by Mingyuan Shi and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, the experiments are conducted at the Jenaer Titanium: Sapphire 200 Terawatt Laser System (JETi200) located in Jena, Germany. With its excellent temporal contrast, the few-nanometer freestanding target can remain in a solid state for a few picoseconds before the main pulse arrives, greatly reducing the pre-expansion of the target. The resulting proton beams exhibit distinctive features in terms of cut-off energy and energy spectrum distribution. The proton beams in the presented experiment show a more than 30 MeV monoenergetic peak under the circularly polarized laser, and the highest peak particle kinetic energy per Joule of laser energy is around 20MeV/J. As opposed to the circularly polarized driving light, the cut-off energy shows weak dependence on the target thickness when irradiated with linearly polarized light. Moreover, the implementation of a transmission light diagnostic in the experiment indicates that the transmission light of the main pulse is significantly weaker than that in other similar experiments. The energy and energy spectrum of the protons provide the potential to conduct in vivo research and proton skin therapy using the Terawatt-level laser system. Laser contrast significantly impacts laser-driven ion acceleration, as low contrast can lead to premature expansion of thin targets. The evolution of premature expansion, caused by pre-pulses, is primarily based on numerical calculations research. However, in this paper, I conduct a comprehensive experimental study of pre-pulse-induced pre-plasma evolution, including the measurement of pre-plasma evolution time and comparison with a previous numerical model. This investigation is especially beneficial for the latest generation of laser ion accelerators, as it enables the precise quantification of temporal contrast requirements in the Petawatt laser driver era.

Download or read book Plasma Physics via Computer Simulation written by C.K. Birdsall and published by CRC Press. This book was released on 2018-10-08 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Divided into three main parts, the book guides the reader to an understanding of the basic concepts in this fascinating field of research. Part 1 introduces you to the fundamental concepts of simulation. It examines one-dimensional electrostatic codes and electromagnetic codes, and describes the numerical methods and analysis. Part 2 explores the mathematics and physics behind the algorithms used in Part 1. In Part 3, the authors address some of the more complicated simulations in two and three dimensions. The book introduces projects to encourage practical work Readers can download plasma modeling and simulation software — the ES1 program — with implementations for PCs and Unix systems along with the original FORTRAN source code. Now available in paperback, Plasma Physics via Computer Simulation is an ideal complement to plasma physics courses and for self-study.

Download or read book Theoretical and Numerical Study of the Laser plasma Ion Acceleration written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The laser driven ion acceleration is a burgeoning field of resarch and is attracting a growing number of scientists since the first results reported in 2000 obtained irradiating thin solid foils by high power laser pulses. The growing interest is driven by the peculiar characteristics of the produced bunches, the compactness of the whole accelerating system and the very short accelerating length of this all-optical accelerators. A fervent theoretical and experimental work has been done since then. An important part of the theoretical study is done by means of numerical simulations and the most widely used technique exploits PIC codes ("Particle In Cell'"). In this thesis the PIC code AlaDyn, developed by our research group considering innovative algorithms, is described. My work has been devoted to the developement of the code and the investigation of the laser driven ion acceleration for different target configurations. Two target configurations for the proton acceleration are presented together with the results of the 2D and 3D numerical investigation. One target configuration consists of a solid foil with a low density layer attached on the irradiated side. The nearly critical plasma of the foam layer allows a very high energy absorption by the target and an increase of the proton energy up to a factor 3, when compared to the ``pure'' TNSA configuration. The differences of the regime with respect to the standard TNSA are described The case of nearly critical density targets has been investigated with 3D simulations. In this case the laser travels throughout the plasma and exits on the rear side. During the propagation, the laser drills a channel and induce a magnetic vortex that expanding on the rear side of the targer is source of a very intense electric field. The protons of the plasma are strongly accelerated up to energies of 100 MeV using a 200PW laser.

Download or read book Proton Acceleration in Ultra Relativistic Laser Plasma Interaction written by Tong-Pu Yu and published by LAP Lambert Academic Publishing. This book was released on 2012 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the rapid development of laser systems, plasma-based laser-driven ion acceleration has drawn increasing attention these years. In this book, one of the most efficient and promising ion acceleration mechanisms, so-called radiation pressure acceleration or light-sail regime is re-visited and studied in detail by theoretical analysis and multi-dimensional particle-in-cell (PIC) simulations. Based on a simple "flying plasma mirror" model, accurate scaling laws of the final ion energy, velocity, momentum, and energy coupling efficiency in the light-sail regime have been derived. For smooth proton acceleration, a shaped foil target or a density-modulated foil target is suggested to overcome the foil deformation when a transversely Gaussian laser pulse irradiates the foil. GeV proton beams can be generated with a well-defined quasi-monoenergetic feature in the energy spectrum. For stable proton acceleration in the light-sail regime, a two-ion-species shaped foil target is proposed and demonstrated by a series of PIC simulations. Hard X-ray gernation and attosecond electron beams are also stuided and verified in the light-sail regime.

Download or read book Experimental Study of Laser driven Electron and Proton Acceleration written by Salima Abuazoum and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis addresses two important topics in the field of laser-driven plasma accelerators. Firstly, the research investigates the generation of relativistic electron beams through laser-wakefield acceleration (LWFA) by applying novel tapered capillary discharge waveguide accelerators, produced by femtosecond laser micromachining. A stable plasma waveguide is formed in a hydrogen-filled capillary driven by an all-solid state high-voltage pulser, specially constructed for this purpose. A longitudinal density taper has been confirmed by measurement of the transverse plasma density profiles at both ends of the waveguide and efficient guiding of low intensity (~1012 W/cm2), ultra-short duration (50 fs) laser pulses is demonstrated. For optimal high-power laser conditions (intensity of 1.6 x 1018 W/cm2), electron beams are produced and compared in positively tapered, negatively tapered and straight capillaries with similar plasma densities of 3-6 x 1018 cm-3 over a length of 4 cm. In all three capillaries, low charge (

Download or read book On the Use of Multiple High Intensity Laser Pulses in Ion Acceleration Experiments written by Graeme Gordon Scott and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compact laser driven ion sources have inspired cautious optimism that they may provide an alternative to conventional accelerators for existing applications, such as in medicine, or aid the realisation of new ones such as fusion energy. However, the sources must be developed, with increased conversion efficiency of laser to proton energy being high on the list of requirements. Recent reports in the literature have shown that record conversion efficiencies can be achieved with double pulse interactions, and this thesis proceeds with this theme. The double pulse operation of the plasma mirror is characterised for the first time, in terms of the post interaction far field quality, and integrated reflectivity. The main pulse reflectivity is significantly enhanced to 96% and the far field remains of high optical quality up to five picoseconds after the prepulse interaction, within the regime for conversion efficiency enhancement. These observations are explained by perturbations of the quasi-near field intensity distribution seeding nonuniformities in the plasma expansion of the plasma mirror surface. A novel plasma half cavity target geometry is investigated which utilises the high fraction of laser energy reflected from an ionised surface and refocuses it such that a double pulse interaction is attained. This new geometry is found to double the laser to proton energy conversion efficiency, compared with planar foil interactions and to modify the low energy region of the proton spectrum. For pulse separations of tens of picoseconds, a long time delay regime is identified for planar foil interactions, where a significant reduction in maximum proton energy and conversion efficiency is reversed, and return to that expected for single pulse interactions. This is explained by the main pulse interacting with bulk target expansion induced by the prepulse. Increased electron temperatures from enhanced absorption in the preplasma are found to mitigate the detrimental effects on ion acceleration, associated with rear surface density scale lengths.