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Dynamics Of Electron Acceleration In Laser Driven Wakefields
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Book Synopsis Laser Wakefield Electron Acceleration by : Karl Schmid
Download or read book Laser Wakefield Electron Acceleration written by Karl Schmid and published by Springer Science & Business Media. This book was released on 2011-05-18 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. This process, known as laser wakefield acceleration (LWFA), relies on strongly driven plasma waves for the generation of accelerating gradients in the vicinity of several 100 GV/m, a value four orders of magnitude larger than that attainable by conventional accelerators. This thesis demonstrates that laser pulses with an ultrashort duration of 8 fs and a peak power of 6 TW allow the production of electron energies up to 50 MeV via LWFA. The special properties of laser accelerated electron pulses, namely the ultrashort pulse duration, the high brilliance, and the high charge density, open up new possibilities in many applications of these electron beams.
Book Synopsis Dynamics of Electron Acceleration in Laser-driven Wakefields by : Antonia Popp
Download or read book Dynamics of Electron Acceleration in Laser-driven Wakefields written by Antonia Popp and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laser Wakefield and Direct Acceleration in the Plasma Bubble Regime by : Zhang, Xi (Ph. D.)
Download or read book Laser Wakefield and Direct Acceleration in the Plasma Bubble Regime written by Zhang, Xi (Ph. D.) and published by . This book was released on 2017 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser wakefield acceleration (LWFA) and direct laser acceleration (DLA) are two different kinds of laser plasma electron acceleration mechanisms. LWFA relies on the laser-driven plasma wave to accelerate electrons. The interaction of ultra-short ultra-intensive laser pulses with underdense plasma leads the LWFA into a highly nonlinear regime (“plasma bubble regime”) that attracts particular interest nowadays. DLA accelerates electrons by laser electromagnetic wave in the ion channel or the plasma bubble through the Betatron resonance. This dissertation presents a hybrid laser plasma electron acceleration mechanism. We investigate its features through particle-in-cell (PIC) simulations and the single particle model. The hybrid laser plasma electron acceleration is the merging concept between the LWFA and the DLA, so called laser wakefield and direct acceleration (LWDA). The requirements of the initial conditions of the electron to undergo the LWDA are determined. The electron must have a large initial transverse energy. Two electron injection mechanisms that are suitable for the LWDA, density bump injection and ionization induced injection, are studied in detail. The features of electron beam phase space and electron dynamics are explored. Electron beam phase space appears several unique features such as spatially separated two groups, the correlation between the transverse energy and the relativistic factor and the double-peak spectrum. Electrons are synergistically accelerated by the wakefield as well as by the laser electromagnetic field in the laser-driven plasma bubble. LWDA are also investigated in the moderate power regime (10 TW) in regarding the effects of laser color and polarization. It is found that the frequency upshift laser pulse has better performance on avoiding time-jitter of electron energy spectra, electron final energy and electron charge yield. Some basic characters that related to the LWDA such as the effects of the subluminal laser wave, the effects of the longitudinal accelerating field, the electron beam emittance, the electron charge yield and potentially applications as radiation source are discussed.
Download or read book Laser Wakefield Acceleration written by and published by . This book was released on 2014 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle accelerators enable scientists to study the fundamental structure of the universe, but have become the largest and most expensive of scientific instruments. In this project, we advanced the science and technology of laser-plasma accelerators, which are thousands of times smaller and less expensive than their conventional counterparts. In a laser-plasma accelerator, a powerful laser pulse exerts light pressure on an ionized gas, or plasma, thereby driving an electron density wave, which resembles the wake behind a boat. Electrostatic fields within this plasma wake reach tens of billions of volts per meter, fields far stronger than ordinary non-plasma matter (such as the matter that a conventional accelerator is made of) can withstand. Under the right conditions, stray electrons from the surrounding plasma become trapped within these "wake-fields", surf them, and acquire energy much faster than is possible in a conventional accelerator. Laser-plasma accelerators thus might herald a new generation of compact, low-cost accelerators for future particle physics, x-ray and medical research. In this project, we made two major advances in the science of laser-plasma accelerators. The first of these was to accelerate electrons beyond 1 gigaelectronvolt (1 GeV) for the first time. In experimental results reported in Nature Communications in 2013, about 1 billion electrons were captured from a tenuous plasma (about 1/100 of atmosphere density) and accelerated to 2 GeV within about one inch, while maintaining less than 5% energy spread, and spreading out less than 1/2 milliradian (i.e. 1/2 millimeter per meter of travel). Low energy spread and high beam collimation are important for applications of accelerators as coherent x-ray sources or particle colliders. This advance was made possible by exploiting unique properties of the Texas Petawatt Laser, a powerful laser at the University of Texas at Austin that produces pulses of 150 femtoseconds (1 femtosecond is 10-15 seconds) in duration and 150 Joules in energy (equivalent to the muzzle energy of a small pistol bullet). This duration was well matched to the natural electron density oscillation period of plasma of 1/100 atmospheric density, enabling efficient excitation of a plasma wake, while this energy was sufficient to drive a high-amplitude wake of the right shape to produce an energetic, collimated electron beam. Continuing research is aimed at increasing electron energy even further, increasing the number of electrons captured and accelerated, and developing applications of the compact, multi-GeV accelerator as a coherent, hard x-ray source for materials science, biomedical imaging and homeland security applications. The second major advance under this project was to develop new methods of visualizing the laser-driven plasma wake structures that underlie laser-plasma accelerators. Visualizing these structures is essential to understanding, optimizing and scaling laser-plasma accelerators. Yet prior to work under this project, computer simulations based on estimated initial conditions were the sole source of detailed knowledge of the complex, evolving internal structure of laser-driven plasma wakes. In this project we developed and demonstrated a suite of optical visualization methods based on well-known methods such as holography, streak cameras, and coherence tomography, but adapted to the ultrafast, light-speed, microscopic world of laser-driven plasma wakes. Our methods output images of laser-driven plasma structures in a single laser shot. We first reported snapshots of low-amplitude laser wakes in Nature Physics in 2006. We subsequently reported images of high-amplitude laser-driven plasma "bubbles", which are important for producing electron beams with low energy spread, in Physical Review Letters in 2010. More recently, we have figured out how to image laser-driven structures that change shape while propagating in a single laser shot. The latter techniques, which use t ...
Book Synopsis Optically Guided Laser Wakefield Acceleration by :
Download or read book Optically Guided Laser Wakefield Acceleration written by and published by . This book was released on 1993 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The possibility of utilizing the fields of an intense laser beam to accelerate particles to high energies has attracted a great deal of interest. The study of laser driven accelerators is motivated by the ultrahigh fields associated with high intensity laser pulses. The peak amplitude of the transverse electric field of the laser pulse is given . A laser driven accelerator that has a number of attractive features is the laser wakefield accelerator (LWFA). In the LWFA, a short intense laser pulse propagates through an underdense plasma. The ponderomotive force associated with the laser pulse envelope expels electrons from the region of the laser pulse. If the laser pulse is sufficiently intense, virtually all of the plasma electrons will be expelled. When the laser pulse length is approximately equal to the plasma wavelength, large amplitude plasma waves (wakefields) will be excited with phase velocities approximately equal to the laser pulse group velocity. The axial and transverse electric fields associated with the wakefield can accelerate and focus a trailing electron beam. The ratio of the accelerating field, E sub z, to the laser field in the LWFA is given.
Book Synopsis Phase Space Dynamics in Plasma Based Wakefield Acceleration by : Xinlu Xu
Download or read book Phase Space Dynamics in Plasma Based Wakefield Acceleration written by Xinlu Xu and published by Springer Nature. This book was released on 2020-01-02 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores several key issues in beam phase space dynamics in plasma-based wakefield accelerators. It reveals the phase space dynamics of ionization-based injection methods by identifying two key phase mixing processes. Subsequently, the book proposes a two-color laser ionization injection scheme for generating high-quality beams, and assesses it using particle-in-cell (PIC) simulations. To eliminate emittance growth when the beam propagates between plasma accelerators and traditional accelerator components, a method using longitudinally tailored plasma structures as phase space matching components is proposed. Based on the aspects above, a preliminary design study on X-ray free-electron lasers driven by plasma accelerators is presented. Lastly, an important type of numerical noise—the numerical Cherenkov instabilities in particle-in-cell codes—is systematically studied.
Book Synopsis Study of Relativistic Electrons Generated from Ultra-intense Laser-plasma Interaction Relevant to Laser Wakefield Acceleration and Fast Ignition Laser Fusion by : Mianzhen Mo
Download or read book Study of Relativistic Electrons Generated from Ultra-intense Laser-plasma Interaction Relevant to Laser Wakefield Acceleration and Fast Ignition Laser Fusion written by Mianzhen Mo and published by . This book was released on 2015 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-intense (> 10^18 W/cm^2) laser interaction with matter is capable of producing relativistic electrons which have a variety of applications in scientific and medical research. Knowledge of various aspects of these hot electrons is important in harnessing them for various applications. Of particular interest for this thesis is the investigation of hot electrons generated in the areas of Laser Wakefield Acceleration (LWFA) and Fast Ignition (FI). LWFA is a physical process in which electrons are accelerated by the strong longitudinal electrostatic fields that are formed inside the plasma cavities or wakes produced by the propagation of an ultra-intense laser pulse through an under-dense plasma. The accelerating E-fields inside the cavities are 1000 times higher than those of conventional particle accelerators and can accelerate electrons to the relativistic regime in a very short distance, on the order of a few millimeters. In addition, Betatron X-ray radiation can be produced from LWFA as a result of the transverse oscillations of the relativistic electrons inside the laser wakefield driven cavity. The pulse duration of Betatron radiation can be as short as a few femtoseconds, making it an ideal probe for measuring physical phenomena taking place on the time scale of femtoseconds. Experimental research on the electron acceleration of the LWFA has been conducted in this thesis and has led to the generation of mono-energetic electron bunches with peak energies ranging from a few hundreds of MeV to 1 GeV. In addition, the Betatron radiation emitted from LWFA was successfully characterized based on a technique of reflection off a grazing incidence mirror. Furthermore, we have developed a Betatron X-ray probe beamline based on the technique of K-shell absorption spectroscopy to directly measure the temporal evolution of the ionization states of warm dense aluminum. With this, we have achieved for the first time direct measurements of the ionization states of warm dense aluminum using Betatron X-ray radiation probing. Fast Ignition (FI) is an advanced scheme for inertial confinement fusion (ICF), in which the fuel ignition process is decoupled from its compression. Comparing with the conventional central hot-spot scheme for ICF, FI has the advantages of lower ignition threshold and higher gain. The success of FI relies on efficient energy coupling from the heating laser pulse to the hot electrons and subsequent transport of their energy to the compressed fuel. As a secondary part of this thesis, the transport of hot electrons in overdense plasma relevant to FI was studied. In particular, the effect of resistive layers within the target on the hot electron divergence and absorption was investigated. Experimental measurements were carried out and compared to simulations indicating minimal effect on the beam divergence but some attenuation through higher atomic number intermediate layers was observed.
Book Synopsis Challenges and Goals for Accelerators in the XXI Century by : Oliver Brning
Download or read book Challenges and Goals for Accelerators in the XXI Century written by Oliver Brning and published by World Scientific. This book was released on 2015 with total page 855 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The past 100 years of accelerator-based research have led the field from first insights into the structure of atoms to the development and confirmation of the Standard Model of physics. Accelerators have been a key tool in developing our understanding of the elementary particles and the forces that govern their interactions. This book describes the past 100 years of accelerator development with a special focus on the technological advancements in the field, the connection of the various accelerator projects to key developments and discoveries in the Standard Model, how accelerator technologies open the door to other applications in medicine and industry, and finally presents an outlook of future accelerator projects for the coming decades."--Provided by publisher.
Book Synopsis Laser Wakefield Electron Acceleration Over 100 MeV Driven by a Femtosecond Terawatt Laser Pulse by : M. Kando
Download or read book Laser Wakefield Electron Acceleration Over 100 MeV Driven by a Femtosecond Terawatt Laser Pulse written by M. Kando and published by . This book was released on 1997 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Study of Laser-driven Electron and Proton Acceleration by : Salima Abuazoum
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 (
Book Synopsis Beam Acceleration In Crystals And Nanostructures - Proceedings Of The Workshop by : Gerard Mourou
Download or read book Beam Acceleration In Crystals And Nanostructures - Proceedings Of The Workshop written by Gerard Mourou and published by . This book was released on 2020 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laser Driven Electron Acceleration in Vacuum, Gases and Plasmas by :
Download or read book Laser Driven Electron Acceleration in Vacuum, Gases and Plasmas written by and published by . This book was released on 1996 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper discusses some of the important issues pertaining to laser acceleration in vacuum, neutral gases and plasmas. The limitations of laser vacuum acceleration as they relate to electron slippage, laser diffraction, material damage and electron aperture effects, are discussed. An inverse Cherenkov laser acceleration configuration is presented in which a laser beam is self guided in a partially ionized gas. Optical self guiding is the result of a balance between the nonlinear self focusing properties of neutral gases and the diffraction effects of ionization. The stability of self guided beams is analyzed and discussed. In addition, aspects of the laser wakefield accelerator are presented and laser driven accelerator experiments are briefly discussed.
Book Synopsis Investigation of Electron Acceleration and Deceleration in Plasmas by : Shao-Wei Chou
Download or read book Investigation of Electron Acceleration and Deceleration in Plasmas written by Shao-Wei Chou and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2016-05-24 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work covers several aspects related to Laser WakeField Acceleration (LWFA). A strong and ultrashort laser pulse can generate plasma waves with accelerating gradients up to 100s GV/m, four orders of magnitude higher than a conventional radio frequency linear accelerator. The LWFA electrons have been characterized as an ultra-short and high brilliance source. These remarkable properties lead to a compact accelerator which is of great scientific interest for building a table-top coherent free electron laser as well as a single-shot electron diffraction device. On the other hand, a new application of LWFA is to utilize the high peak current LWFA electron bunch to drive a wakefield efficiently inside a high density underdense plasma. The resulting wakefield quickly decelerates the driver bunch or accelerates a properly designed witness bunch, and therefore the plasma is utilized as a compact beam dump or an afterburner staged after a regular LWFA.
Book Synopsis Direct Laser Acceleration in Laser Wakefield Accelerators by : Jessica Shaw
Download or read book Direct Laser Acceleration in Laser Wakefield Accelerators written by Jessica Shaw and published by . This book was released on 2016 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, the direct laser acceleration (DLA) of ionization-injected electrons in a laser wakefield accelerator (LWFA) operating in the quasi-blowout regime has been investigated through experiment and simulation. In the blowout regime of LWFA, the radiation pressure of an intense laser pulse can push a majority of the plasma electrons out and around the main body of the pulse. The expelled plasma electrons feel the electrostatic field of the relatively-stationary ions and are thus attracted back towards the laser axis behind the laser pulse where they overshoot the axis and set up a wake oscillation. When ionization injection is used, the inner-shell electrons of higher-Z dopant atoms are tunnel ionized near the peak of the laser pulse. Those electrons slip back relative to the wake until they gain enough energy from the longitudinal wakefield to become trapped. Those electrons that are trapped off-axis will undergo betatron oscillations in response to the linear transverse focusing force of the ions. Through experiments and supporting simulations, this dissertation demonstrates that when there is a significant overlap between the drive laser and the trapped electrons in a LWFA cavity, the accelerating electrons can gain energy from the DLA mechanism in addition to LWFA. When laser pulse overlaps the trapped electrons, the betatron oscillations of the electrons in the plane of the laser polarization can lead to an energy transfer from the transverse electric field of the laser to the transverse momentum of the electrons. This enhanced transverse momentum can then be converted into increased longitudinal momentum via the v x B force of the laser. This process is known as DLA. In this experimental work, the properties of the electron beams produced in a LWFA where the electrons are injected by ionization injection and become trapped without escaping the laser field have been investigated. The maximum measured energy of the produced electron beams scales with the overlap between the electrons and the laser. Undispersed electrons beams are observed to be elliptical in the plane of the laser polarization, and the energy spectrum splits into a fork at higher energies when the electrons beams are dispersed orthogonal to the direction of the laser polarization. These characteristic features are reproduced in particle-in-cell (PIC) code simulations where particle tracking was used to demonstrate that such spectral features are signatures of the presence of DLA in LWFA. Further PIC simulations comparing LWFA with and without DLA show that the presence of DLA can lead to electron beams that have maximum energies that exceed the estimates given by the theory for the ideal blowout regime. The magnitude of the contribution of DLA to the energy gained by the electron was found to be on the order of the LWFA contribution. In the LWFAs studied here, both DLA and LWFA participate in accelerating the bulk of the electrons in the produced electron beam. The presence of DLA in a LWFA can also lead to enhanced betatron oscillation amplitudes and increased divergence in the direction of the laser polarization.
Book Synopsis Laser-Driven Particle Acceleration Towards Radiobiology and Medicine by : Antonio Giulietti
Download or read book Laser-Driven Particle Acceleration Towards Radiobiology and Medicine written by Antonio Giulietti and published by Springer. This book was released on 2016-05-04 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with the new method of laser-driven acceleration for application to radiation biophysics and medicine. It provides multidisciplinary contributions from world leading scientist in order to assess the state of the art of innovative tools for radiation biology research and medical applications of ionizing radiation. The book contains insightful contributions on highly topical aspects of spatio-temporal radiation biophysics, evolving over several orders of magnitude, typically from femtosecond and sub-micrometer scales. Particular attention is devoted to the emerging technology of laser-driven particle accelerators and their application to spatio-temporal radiation biology and medical physics, customization of non-conventional and selective radiotherapy and optimized radioprotection protocols.
Book Synopsis LASER WAKEFIELD ACCELERATION DRIVEN BY ATF CO2 LASER (STELLA-LW). by :
Download or read book LASER WAKEFIELD ACCELERATION DRIVEN BY ATF CO2 LASER (STELLA-LW). written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new experiment has begun that builds upon the successful Staged Electron Laser Acceleration (STELLA) experiment, which demonstrated high-trapping efficiency and narrow energy spread in a staged laser-driven accelerator. STELLA was based upon inverse free electron lasers (IFEL); the new experiment, called STELLA-LW, is based upon laser wakefield acceleration (LWFA). The first phase of STELLA-LW will be to demonstrate LWFA in a capillary discharge driven by the Brookhaven National Laboratory Accelerator Test Facility (ATF) terawatt CO[sub 2] laser beam. This will be the first time LWFA is conducted at 10.6-[micro]m laser wavelength. It will also be operating in an interesting pseudo-resonant regime where the laser pulse length is too long for resonant LWFA, but too short for self-modulated LWFA. Analysis has shown that in pseudo-resonant LWFA, pulse-steepening effects occur on the laser pulse that permits generation of strong wakefields. Various approaches are being explored for the capillary discharge including polypropylene and hydrogen-filled capillaries. Planned diagnostics for the experiment include coherent Thomson scattering (CTS) to detect the wakefield generation. This will be one of the first times CTS is used on a capillary discharge.
Book Synopsis An Exploration on Electron Bunching of Ionization Induced Self-injection in Laser Wakefield Accelerators by : Deyun Li (M.A.)
Download or read book An Exploration on Electron Bunching of Ionization Induced Self-injection in Laser Wakefield Accelerators written by Deyun Li (M.A.) and published by . This book was released on 2016 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma-based wakefield accelerator is attractive for generating quasi-monoenergetic electron beams using the bubble regime. The bubble is formed by an intense driver, which propagates through the plasma and expels all electrons transversely, creating a cavity free of cold plasma electrons that trailing behind the driver. Self-injection is applicable in the bubble regime, which can produce bunches of quasi-monoenergetic electrons. (1) Such electron bunching structure can be diagnosed with coherent transition radiation and may be exploited to generate powerful high frequency radiation [16].This thesis focuses on electron bunching phenomenon through WAKE simulations and theoretical analysis. The simulation is completed under laser-driven field ionization wakefield acceleration. The code is improved by taking into consideration the high frequency property of laser driver in wakefield acceleration. Finer grid size is introduced to the ionization injection part of WAKE, for increasing simulation accuracy without much sacrifice of programming efficiency. Various conditions for optimal bunching in the trapped electrons are explored computationally and analytically.
