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Laser Wakefield Acceleration Of Electrons To Gev Energies And Temporal Laser Pulse Compression Characterization In A Capillary Discharge Waveguide
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Book Synopsis Laser Wakefield Acceleration of Electrons to GeV Energies and Temporal Laser Pulse Compression Characterization in a Capillary Discharge Waveguide by : Paul Andreas Walker
Download or read book Laser Wakefield Acceleration of Electrons to GeV Energies and Temporal Laser Pulse Compression Characterization in a Capillary Discharge Waveguide written by Paul Andreas Walker and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Investigation of Laser-wakefield Acceleration in the Hydrogen-filled Capillary Discharge Waveguide by : Thomas P. A. Ibbotson
Download or read book An Investigation of Laser-wakefield Acceleration in the Hydrogen-filled Capillary Discharge Waveguide written by Thomas P. A. Ibbotson and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a detailed investigation into the process of laser-wakefield acceleration (LWFA) for the generation of high-energy electron beams using the hydrogen-filled capillary discharge waveguide. In only the second experiment to be performed using the newly commissioned Astra-Gemini laser at the Rutherford Appleton Laboratory, electron beams were accelerated to energies greater than 0.5 GeV by laser pulses of energy 2.5J and peak power of 30T\~T. The injec- tion and acceleration of electron beams was seen to depend on the state of the plasma channel for axial electron densities less than 2.5 x 1018 cm -3. With the aid of simulations performed using the code WAKE it was found that the plasma channel allows the laser pulse to maintain its self-focussed spot size along the length of the capillary even below the critical power for self-guiding. It was found that the threshold laser energy required for the production of elec- tron beams was reduced by the use of an aperture placed early in the laser system. This was attributed to the increased energy contained in the central part of the focal spot of the laser. A short paper on this work was published in Physical Review Special Topics - Accelerators and Beams and a longer paper was published in the New Journal of Physics. Transverse interferometry was used to measure the electron density of the plasma channel used in the Astra-Gemini experiments. An imaging system was devised which used cylindrical optics to increase the field of view of the capillary longitudinally, whilst maintaining the trans- verse resolution. The measured properties were consistent with previous measurements made by Gonsalves et al. [J]. The observed longitudinal variations in the plasma channel parameters were not found to be significant enough to affect the injection process.
Book Synopsis Magnetically Controlled Plasma Waveguide For Laser Wakefield Acceleration by :
Download or read book Magnetically Controlled Plasma Waveguide For Laser Wakefield Acceleration written by and published by . This book was released on 2008 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: An external magnetic field applied to a laser plasma is shown produce a plasma channel at densities relevant to creating GeV monoenergetic electrons through laser wakefield acceleration. Furthermore, the magnetic field also provides a pressure to help shape the channel to match the guiding conditions of an incident laser beam. Measured density channels suitable for guiding relativistic short-pulse laser beams are presented with a minimum density of 5 x 1017 cm−3 which corresponds to a linear dephasing length of several centimeters suitable for multi-GeV electron acceleration. The experimental setup at the Jupiter Laser Facility, Lawrence Livermore National Laboratory, where a 1-ns, 150 J 1054 nm laser will produce a magnetically controlled channel to guide a
Book Synopsis Experimental Study of Self-trapping in Capillary Discharge Guided Laser Wakefield Acceleration by :
Download or read book Experimental Study of Self-trapping in Capillary Discharge Guided Laser Wakefield Acceleration written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser wakefield acceleration experiments were carried out using hydrogen-filled capillary discharge waveguides. For a 33 mm long, 300 mu m capillary, parameter regimes with high energy electron beams (up to 1 GeV) and stable 0.5 GeV were found. In the high energy regime, the electron beam peak energy was correlated with the number of trapped electrons. For a 15 mm long, 200 mu m diameter capillary, quasi-monoenergetic e beams up to 300 MeV were observed. By de-tuning discharge delay from optimum guiding performance, self-trapping was found to be stabilized.
Book Synopsis Laser Wakefield Acceleration in the Hydrogen-filled Capillary Discharge Waveguide by : Thomas Rowlands-Rees
Download or read book Laser Wakefield Acceleration in the Hydrogen-filled Capillary Discharge Waveguide written by Thomas Rowlands-Rees and published by . This book was released on 2009 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Magnetically Controlled Optical Plasma Waveguide for Electron Acceleration by :
Download or read book Magnetically Controlled Optical Plasma Waveguide for Electron Acceleration written by and published by . This book was released on 2008 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to produce multi-Gev electrons from Laser Wakefield Accelerators, we present a technique to guide high power laser beams through underdense plasma. Experimental results from the Jupiter Laser Facility at the Lawrence Livermore National Laboratory that show density channels with minimum plasma densities below 5 x 1017 cm−3 are presented. These results are obtained using an external magnetic field (
Book Synopsis Proof-of-principle Experiments of Laser Wakefield Acceleration by :
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.
Book Synopsis LASER WAKEFIELD ACCELERATION BEYOND 1 GeV USING IONIZATION INDUCED INJECTION* by :
Download or read book LASER WAKEFIELD ACCELERATION BEYOND 1 GeV USING IONIZATION INDUCED INJECTION* written by and published by . This book was released on 2011 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of laser wake field accelerator experiments leading to electron energy exceeding 1 GeV are described. Theoretical concepts and experimental methods developed while conducting experiments using the 10 TW Ti:Sapphire laser at UCLA were implemented and transferred successfully to the 100 TW Callisto Laser System at the Jupiter Laser Facility at LLNL. To reach electron energies greater than 1 GeV with current laser systems, it is necessary to inject and trap electrons into the wake and to guide the laser for more than 1 cm of plasma. Using the 10 TW laser, the physics of self-guiding and the limitations in regards to pump depletion over cm-scale plasmas were demonstrated. Furthermore, a novel injection mechanism was explored which allows injection by ionization at conditions necessary for generating electron energies greater than a GeV. The 10 TW results were followed by self-guiding at the 100 TW scale over cm plasma lengths. The energy of the self-injected electrons, at 3 x 1018 cm−3 plasma density, was limited by dephasing to 720 MeV. Implementation of ionization injection allowed extending the acceleration well beyond a centimeter and 1.4 GeV electrons were measured.
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.
Book Synopsis Spatiotemporal Pulse Shaping for Laser-plasma-based Applications by : Philip K. Franke
Download or read book Spatiotemporal Pulse Shaping for Laser-plasma-based Applications written by Philip K. Franke and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Laser produced plasma provides a basis for many emerging technologies because it can interact with photons and charged particles in powerful and unique ways. These laser-plasma-based applications frequently rely on the controlled coupling of the laser pulse to the plasma to achieve the desired effects. Spatiotemporal (ST) pulse shaping, referring to the intentional correlation of the spatial and temporal characteristics of the laser pulse, can enhance control over the laser-plasma coupling improving the utility of laser-plasma-based applications. This work presents the basic theory of two ST shaping techniques, the chromatic flying focus (CFF) [D.H. Froula et al., "Spatiotemporal control of laser intensity" Nature Photonics 12, 262?265 (2018), D.H. Froula et al., "Flying focus: Spatial and temporal control of intensity for laser-based applications" Physics of Plasmas 26] and the ultrashort flying focus (UFF) ["Dephasingless Laser Wakefield Acceleration" Physical Review Letters 124, 134802 (2020)], and explores their applications experimentally and theoretically. Both techniques have at least three advantages in common: 1) laser pulse focusing is cylindrically symmetric, allowing high focused intensities to be reached, 2) the focal range is decoupled from the spot size, allowing high intensity to be maintained over long distances, and 3) the intensity peak velocity (focal velocity, v f) is decoupled from the laser group velocity, facilitating intensity peaks with tunable velocity. CFF pulses derived from the Multi-Terawatt laser at the Laboratory for Laser Energetics were used to drive ionization waves of arbitrary velocity (IWAVs) in air. These IWAVs, which are the moving interface between a neutral medium and an ionized plasma, moved at the focal velocity v f when driven by low energy pulses with uniform power spectra, agreeing with theoretical predictions. Focal velocity ranges shown computationally to mitigate ionization refraction were also confirmed [D. Turnbull et al., "Ionization Waves of Arbitrary Velocity" Physical Review Letters 120, 225001 (2018), J.P. Palastro et al., "Ionization waves of arbitrary velocity driven by a flying focus" Physical Review A 97, 033835 (2018)]. Later experiments demonstrated IWAVs of large diameter using defocused laser pulses in a gas jet. The non-uniform power spectrum of these higher energy pulses resulted in experimentally observable changes to the IWAV diameter and trajectory. An analytic theory predicting the IWAV trajectory and diameter for CFF pulses with non-uniform power spectra was developed, and broadly agreed with the experimental observations. This theory was used to propose the use of power spectrum shaping as a way to better tune the IWAV characteristics [P. Franke et al., "Measurement and control of large diameter ionization waves of arbitrary velocity" Optics Express 27, 31978?31988 (2019)]. Photon acceleration, describing the continual frequency increase accrued by a photon in a time decreasing refractive index gradient as a means to generate extreme ultraviolet light, is an application shown computationally to be advanced by the generation of IWAVs. A computational investigation of three photon acceleration schemes enable by IWAVs is presented. A new optical shock-enhanced self-photon acceleration regime was identified using a finite-difference time-domain computational model. This regime, which is characterized by rapid spectral broadening and temporal compression of the drive laser pulse, could generate isolated attosecond pulses in the extreme ultraviolet with high efficiency [A.J. Howard et al., "Photon Acceleration in a Flying Focus" Physical Review Letters 123, 124801 (2019), P. Franke et al., "Optical shock-enhanced self-photon acceleration" Physical Review A 104, 043520 (2021)]. An experimental platform was developed to measure the UFF, and prototype radial echelon optics were manufactured. The echelon optics were fabricated using vapor-deposition through a rotating mask, and were measured to be suitable for initial experiments. An automated scanning spectral interferometer was built and benchmarked, then used to make initial measurements of the UFF. The UFF was not explicitly demonstrated, but several experimental shortcomings were identified, illuminating a path toward an ultimate demonstration. A successful demonstration of the UFF will immediately enable a series of experiments planned to study dephasingless laser wakefield acceleration and related topics"--Pages xi-xiii
Book Synopsis Plasma Channel Guided Laser Wakefield Accelerator by : Cameron Guy Robinson Geddes
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:
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 Relativistic Electron-cyclotron Resonances in Laser Wakefield Acceleration by : Matthew Schwab
Download or read book Relativistic Electron-cyclotron Resonances in Laser Wakefield Acceleration written by Matthew Schwab and published by . This book was released on 2022* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the magnetized, relativistic plasma that overlaps the pump laser in Laser Wakefield Acceleration (LWFA) was investigated. The Jeti 40 laser was used to drive the plasma wave and a transverse, few-cycle probe pulse in the visible to near-infrared spectrum was implemented to image the laser-plasma interaction. The recorded shadowgrams were sorted depending on the properties of the accelerated electron bunches, and subsequently stitched together based on the timing delay between the pump and probe beams. The resulting data showed two signatures unique to the relativistic, magnetized plasma near the pump pulse. Firstly, a significant change in the brightness modulation of the shadowgrams, coinciding with the location of the pump pulse, shows a strong dependence on the pump's propagation length and the probe's spectrum and polarization. Secondly, after ~1.5 mm of propagation in the plasma, polarization-dependent diffraction rings appear in front of the plasma wave. A mathematical model using relativistic corrections to the Appleton-Hartree equation was developed to explain these signals. By combining the model with data from 2D Particle-in-Cell (PIC) simulations using the VSim code, the plasma's birefringent refractive index distribution was investigated. Simulated shadowgrams of a 3D PIC simulation using the EPOCH code were also analyzed with respect to the aforementioned signals. The results of the study present a compelling description of the pump-plasma interaction. The previously unknown signals arise from relativistic, electron-cyclotron motion originating in the 10s of kilotesla strong magnetic fields of the pump pulse. Advantageously, a VIS-NIR probe is resonant with the cyclotron frequencies at the peak of the pump. With further refinement, the measurement of this phenomenon could allow for the non-invasive experimental visualization of the pump laser's spatio-temporal energy distribution and evolution during propagation through the plasma.
Book Synopsis Preformed Transient Gas Channels for Laser Wakefield Particle Acceleration by :
Download or read book Preformed Transient Gas Channels for Laser Wakefield Particle Acceleration written by and published by . This book was released on 1994 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acceleration of electrons by laser-driven plasma wake fields is limited by the range over which a laser pulse can maintain its intensity. This distance is typically given by the Rayleigh range for the focused laser beam, usually on the order of 0.1 mm to 1 mm. For practical particle acceleration, interaction distances on the order of centimeters are required. Therefore, some means of guiding high intensity laser pulses is necessary. Light intensities on the order of a few times 1017 W/cm2 are required for laser wakefield acceleration schemes using near IR radiation. Gas densities on the order of or greater than 1017 cm−3 are also needed. Laser-atom interaction studies in this density and intensity regime are generally limited by the concomitant problems in beam propagation introduced by the creation of a plasma. In addition to the interaction distance limit imposed by the Rayleigh range, defocusing of the high intensity laser pulse further limits the peak intensity which can be achieved. To solve the problem of beam propagation limitations in laser-plasma wakefield experiments, two potential methods for creating transient propagation channels in gaseous targets are investigated. The first involves creation of a charge-neutral channel in a gas by an initial laser pulse, which then is ionized by a second, ultrashort, high-intensity pulse to create a waveguide. The second method involves the ionization of a gas column by an ultrashort pulse; a transient waveguide is formed by the subsequent expansion of the heated plasma into the neutral gas.
Book Synopsis Laser-plasma Interactions Used for the Acceleration of Electrons by : Evan Stuart Dodd
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:
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.
