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:
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.
Download or read book Applications of Laser Driven Particle Acceleration written by Paul Bolton and published by CRC Press. This book was released on 2018-06-04 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book of its kind to highlight the unique capabilities of laser-driven acceleration and its diverse potential, Applications of Laser-Driven Particle Acceleration presents the basic understanding of acceleration concepts and envisioned prospects for selected applications. As the main focus, this new book explores exciting and diverse application possibilities, with emphasis on those uniquely enabled by the laser driver that can also be meaningful and realistic for potential users. It also emphasises distinction, in the accelerator context, between laser-driven accelerated particle sources and the integrated laser-driven particle accelerator system (all-optical and hybrid versions). A key aim of the book is to inform multiple, interdisciplinary research communities of the new possibilities available and to inspire them to engage with laser-driven acceleration, further motivating and advancing this developing field. Material is presented in a thorough yet accessible manner, making it a valuable reference text for general scientific and engineering researchers who are not necessarily subject matter experts. Applications of Laser-Driven Particle Acceleration is edited by Professors Paul R. Bolton, Katia Parodi, and Jörg Schreiber from the Department of Medical Physics at the Ludwig-Maximilians-Universität München in München, Germany. Features: Reviews the current understanding and state-of-the-art capabilities of laser-driven particle acceleration and associated energetic photon and neutron generation Presents the intrinsically unique features of laser-driven acceleration and particle bunch yields Edited by internationally renowned researchers, with chapter contributions from global experts
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 ...
Download or read book Plasma Channel Guided Laser Wakefield Accelerator written by Cameron Guy Robinson Geddes and published by . This book was released on 2005 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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.
Download or read book Electron Acceleration Mechanisms in the Interaction of Ultrashort Lasers with Underdense Plasmas written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment investigating the production of relativistic electrons from the interaction of ultrashort multi-terawatt laser pulses with an underdense plasma is presented. Electrons were accelerated to tens of MeV and the maximum electron energy increased as the plasma density decreased. Simulations have been performed in order to model the experiment. They show a good agreement with the trends observed in the experiment and the spectra of accelerated electrons could be reproduced successfully. The simulations have been used to study the relative contribution of the different acceleration mechanisms: plasma wave acceleration, direct laser acceleration and stochastic heating. The results show that in low density case (1 percent of the critical density) acceleration by laser is dominant mechanism. The simulations at high density also suggest that direct laser acceleration is more efficient that stochastic heating.
Download or read book Laser Wakefield Acceleration at Reduced Density in the Self Guided Regime written by and published by . This book was released on 2009 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments conducted using a 200TW 60 fs laser have demonstrated up to 720 MeV electrons in the self-guided laser wakefield regime using pure Helium gas jet targets. Charge and energy of the accelerated electrons was measured using an electron spectrometer with a 0.5T magnet and charge callibrated image plates. The self-trapped charge in a helium plasma was shown to fall off with decreasing electron density with a threshold at 2.5 x 1018 (cm−3) below which no charge is trapped. Self-guiding however is shown to continue below this density limitation over distances of 14 mm with an exit spot size of 25[mu]m. Simulations show that injection of electrons at these densities can be assisted through ionization induced trapping in a mix of Helium with 3% Oxygen.
Download or read book JJAP Letters written by and published by . This book was released on 1999 with total page 1064 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Opportunities in Intense Ultrafast Lasers written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2018-01-31 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: The laser has revolutionized many areas of science and society, providing bright and versatile light sources that transform the ways we investigate science and enables trillions of dollars of commerce. Now a second laser revolution is underway with pulsed petawatt-class lasers (1 petawatt: 1 million billion watts) that deliver nearly 100 times the total world's power concentrated into a pulse that lasts less than one-trillionth of a second. Such light sources create unique, extreme laboratory conditions that can accelerate and collide intense beams of elementary particles, drive nuclear reactions, heat matter to conditions found in stars, or even create matter out of the empty vacuum. These powerful lasers came largely from U.S. engineering, and the science and technology opportunities they enable were discussed in several previous National Academies' reports. Based on these advances, the principal research funding agencies in Europe and Asia began in the last decade to invest heavily in new facilities that will employ these high-intensity lasers for fundamental and applied science. No similar programs exist in the United States. Opportunities in Intense Ultrafast Lasers assesses the opportunities and recommends a path forward for possible U.S. investments in this area of science.
Download or read book Simulation of Electron Post acceleration in a Two stage Laser Wakefield Accelerator written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron bunches produced in self-modulated laser wakefield experiments usually have a broad energy spectrum, with most electrons at low energy (1-3 MeV) and only a small fraction at high energy. We propose and investigate further acceleration of such bunches in a channel-guided resonant laser wakefield accelerator. Two-dimensional simulations with and without the effects of self-consistent beam loading are performed and compared. These results indicate that it is possible to trap about 40 percent of the injected bunch charge and accelerate this fraction to an average energy of about 50 MeV in a plasma channel of a few mn.
Download or read book Proof of principle Experiments of Laser Wakefield Acceleration written by and published by . This book was released on 1994 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently there has been a great interest in laser-plasma accelerators as possible next-generation particle accelerators because of their potential for ultra high accelerating gradients and compact size compared with conventional accelerators. It is known that the laser pulse is capable of exciting a plasma wave propagating at a phase velocity close to the velocity of light by means of beating two-frequency lasers or an ultra short laser pulse. These schemes came to be known as the Beat Wave Accelerator (BWA) for beating lasers or as the Laser Wakefield Accelerator (LWFA) for a short pulse laser. In this paper, the principle of laser wakefield particle acceleration has been tested by the Nd:glass laser system providing a short pulse with a power of 10 TW and a duration of 1 ps. Electrons accelerated up to 18 MeV/c have been observed by injecting 1 MeV/c electrons emitted from a solid target by an intense laser impact. The accelerating field gradient of 30 GeV/m is inferred.
Download or read book Accelerating in the Future written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Twenty-five years ago, a new method was proposed for the acceleration of electrons to high energies using lasers. The simplest implementation of a so-called laser wakefield accelerator involves sending an intense laser pulse through a gas to ionize it and form a plasma of dissociated electrons and ions. The radiation pressure of the laser pushes the plasma electrons aside, creating a density modulation, or 'wake'. This changing electron density can result in fields that accelerate particles thousands of times more strongly than in conventional machines, accelerating electrons to high energies in short distances. The compactness of these accelerators would allow higher energies for the frontiers of fundamental physics and make clinical and laboratory applications of accelerators practical. In work that brings the promise of laser-driven particle accelerators dramatically closer to reality, we have produced high-quality electron beams in a plasma channel based accelerating structure akin to an optical fiber of only a few millimeters long.
Download or read book Laser plasma Interactions Used for the Acceleration of Electrons written by Evan Stuart Dodd and published by . This book was released on 1999 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Beam Characteristics of a Laser driven Plasma Wakefield Accelerator written by and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of an electron beam trapped and accelerated in a laser wakefield have been investigated. Plastic scintillating fibers were employed together with position sensitive photomultiplier tubes (PMT) and a series of dipole electro-magnets to study the beam. The measured momentum spectrum peaks around 7 MeV/c with an exponential fall-off at high momenta up to (70.320619.9) MeV/c. The number of electrons detected per bunch is determined to be (2.62060.3)z10^11.
Download or read book Physics of Laser driven Plasma based Acceleration written by Eric Esarey and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The physics of plasma-based accelerators driven by short-pulse lasers is reviewed. This includes the laser wake-field accelerator, the plasma beat wave accelerator, the self-modulated laser wake-field accelerator, and plasma waves driven by multiple laser pulses. The properties of linear and nonlinear plasma waves are discussed, as well as electron acceleration in plasma waves. Methods for injecting and trapping plasma electrons in plasma waves are also discussed. Limits to the electron energy gain are summarized, including laser pulse direction, electron dephasing, laser pulse energy depletion, as well as beam loading limitations. The basic physics of laser pulse evolution in underdense plasmas is also reviewed. This includes the propagation, self-focusing, and guiding of laser pulses in uniform plasmas and plasmas with preformed density channels. Instabilities relevant to intense short-pulse laser-plasma interactions, such as Raman, self-modulation, and hose instabilities, are discussed. Recent experimental results are summarized.
