Download or read book GeV Electron Beams from Cm scale Channel Guided Laser Wakefieldaccelerator written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-wakefield accelerators (LWFA) can produce electricfields of order 10-100 GV/m suitable for acceleration of electrons torelativistic energies. The wakefields are excited by a relativisticallyintense laser pulse propagating through a plasma and have a phasevelocity determined by the group velocity of the light pulse. Twoimportant effects that can limit the acceleration distanceand hence thenet energy gain obtained by an electron are diffraction of the drivelaser pulse and particle-wake dephasing. Diffraction of a focusedultra-short laser pulse can be overcome by using preformed plasmachannels. The dephasing limit can be increased by operating at a lowerplasma density, since this results in an increase in the laser groupvelocity. Here we present detailed results on the generation of GeV-classelectron beams using an intense femtosecond laser beamand a 3.3 cm longpreformed discharge-based plasma channel [W.P. Leemans et al., NaturePhysics 2, 696-699 (2006)]. The use of a discharge-based waveguidepermitted operation at an order ofmagnitude lower density and 15 timeslonger distance than in previous experiments that relied on laserpreformed plasma channels. Laser pulses with peak power ranging from10-50 TW were guided over more than 20 Rayleigh ranges and high-qualityelectron beams with energy up to 1 GeV were obtained by channelling a 40TW peak power laser pulse. The dependence of the electron beamcharacteristics on capillary properties, plasma density, and laserparameters are discussed.
Download or read book Energy Spread Reduction of Electron Beams Produced Via Laser Wakefield Acceleration written by Bradley Bolt Pollock and published by . This book was released on 2012 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser wakefield acceleration of electrons holds great promise for producing ultra-compact stages of GeV scale, high quality electron beams for applications such as x-ray free electron lasers and high energy colliders. Ultra-high intensity laser pulses can be self-guided by relativistic plasma waves over tens of vacuum diffraction lengths, to give>1 GeV energy in cm-scale low density plasma using ionization-induced injection to inject charge into the wake at low densities. This thesis describes a series of experiments which investigates the physics of LWFA in the self-guided blowout regime. Beginning with high density gas jet experiments the scaling of the LWFA-produced electron beam energy with plasma electron density is found to be in excellent agreement with both phenomenological theory and with 3-D PIC simulations. It is also determined that self-trapping of background electrons into the wake exhibits a threshold as a function of the electron density, and at the densities required to produce electron beams with energies exceeding 1 GeV a different mechanism is required to trap charge into low density wakes. By introducing small concentrations of high-Z gas to the nominal He background the ionization-induced injection mechanism is enabled. Electron trapping is observed at densities as low as 1.3x1018 cm−3 in a gas cell target, and 1.45 GeV electrons are demonstrated for the first time from LWFA. This is currently the highest electron energy ever produced from LWFA. The ionization-induced trapping mechanism is also shown to generate quasi-continuous electron beam energies, which is undesirable for accelerator applications. By limiting the region over which ionization-induced trapping occurs, the energy spread of the electron beams can be controlled. The development of a novel two-stage gas cell target provides the capability to tailor the gas composition in the longitudinal direction, and confine the trapping process to occur only in a limited, defined region. Using this technique a 460 MeV electron beam was produced with an energy spread of 5%. This technique is directly scalable to multi-GeV electron beam generation with sub-percent energy spreads.
Download or read book Laser Guiding for GeV Laser Plasma Accelerators written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Guiding of relativistically intense laser beams in preformed plasma channels is discussed for development of GeV-class laser accelerators. Experiments using a channel guided laser wakefield accelerator (LWFA) at LBNL have demonstrated that near mono-energetic 100 MeV-class electron beams can be produced with a 10 TW laser system. Analysis, aided by particle-in-cell simulations, as well as experiments with various plasma lengths and densities, indicate that tailoring the length of the accelerator, together with loading of the accelerating structure with beam, is the key to production of mono-energetic electron beams. Increasing the energy towards a GeV and beyond will require reducing the plasma density and design criteria are discussed for an optimized accelerator module. The current progress and future directions are summarized through comparison with conventional accelerators, highlighting the unique short term prospects for intense radiation sources based on laser-driven plasma accelerators.
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 GeV Electron Beams from a Cm scale Accelerator written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: GeV electron accelerators are essential to synchrotron radiation facilities and free electron lasers, and as modules for high-energy particle physics. Radio frequency based accelerators are limited to relatively low accelerating fields (10-50 MV/m) and hence require tens to hundreds of meters to reach the multi-GeV beam energies needed to drive radiation sources, and many kilometers to generate particle energies of interest to the frontiers of high-energy physics. Laser wakefield accelerators (LWFA) in which particles are accelerated by the field of a plasma wave driven by an intense laser pulse produce electric fields several orders of magnitude stronger (10-100 GV/m) and so offer the potential of very compact devices. However, until now it has not been possible to maintain the required laser intensity, and hence acceleration, over the several centimeters needed to reach GeV energies. For this reason laser-driven accelerators have to date been limited to the 100 MeV scale. Contrary to predictions that PW-class lasers would be needed to reach GeV energies, here we demonstrate production of a high-quality electron beam with 1 GeV energy by channeling a 40 TW peak power laser pulse in a 3.3 cm long gas-filled capillary discharge waveguide. We anticipate that laser-plasma accelerators based on capillary discharge waveguides will have a major impact on the development of future femtosecond radiation sources such as x-ray free electron lasers and become a standard building block for next generation high-energy accelerators.
Download or read book GeV Electron Beams from a Centimeter scale Laser driven Plasmaaccelerator written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Esults are presented on the generation ofquasi-monoenergeticelectron beams with energy up to 1GeV using a 40TWlaser and a 3.3 cm-long hydrogen-filled capillary discharge waveguide. Electron beams were not observed without a plasma channel, indicatingthat self-focusing alone could not be relied upon for effective guidingofthe laser pulse. Results are presented of the electronbeam spectra, andthe dependence of the reliability of producingelectron beams as afunction of laser and plasma parameters.
Download or read book Energy Spread Reduction of Electron Beams Produced Via Laser Wake written by and published by . This book was released on 2012 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser wakefield acceleration of electrons holds great promise for producing ultra-compact stages of GeV scale, high quality electron beams for applications such as x-ray free electron lasers and high energy colliders. Ultra-high intensity laser pulses can be self-guided by relativistic plasma waves over tens of vacuum diffraction lengths, to give>1 GeV energy in cm-scale low density plasma using ionization-induced injection to inject charge into the wake at low densities. This thesis describes a series of experiments which investigates the physics of LWFA in the self-guided blowout regime. Beginning with high density gas jet experiments the scaling of the LWFA-produced electron beam energy with plasma electron density is found to be in excellent agreement with both phenomenological theory and with 3-D PIC simulations. It is also determined that self-trapping of background electrons into the wake exhibits a threshold as a function of the electron density, and at the densities required to produce electron beams with energies exceeding 1 GeV a different mechanism is required to trap charge into low density wakes. By introducing small concentrations of high-Z gas to the nominal He background the ionization-induced injection mechanism is enabled. Electron trapping is observed at densities as low as 1.3 x 1018 cm-3 in a gas cell target, and 1.45 GeV electrons are demonstrated for the first time from LWFA. This is currently the highest electron energy ever produced from LWFA. The ionization-induced trapping mechanism is also shown to generate quasi-continuous electron beam energies, which is undesirable for accelerator applications. By limiting the region over which ionization-induced trapping occurs, the energy spread of the electron beams can be controlled. The development of a novel two-stage gas cell target provides the capability to tailor the gas composition in the longitudinal direction, and confine the trapping process to occur only in a limited, defined region. Using this technique a 460 MeV electron beam was produced with an energy spread of 5%. This technique is directly scalable to multi-GeV electron beam generation with sub-percent energy spreads.
Download or read book Low Energy Spread 100 MeV 1 GeV Electron Bunches from Laserwakefiel D Acceleration at LOASIS written by C. B. Schroeder and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments at the LOASIS laboratory of LBNL recentlydemonstrated production of 100 MeV electron beams with low energy spreadand low divergence from laser wakefield acceleration. The radiationpressure of a 10 TW laser pulse guided over 10 diffraction ranges by aplasma density channel was used to drive an intense plasma wave(wakefield), producing acceleration gradients on the order of 100 GV/m ina mm-scale channel. Beam energy has now been increased from 100 to 1000MeV by using a cm-scale guiding channel at lower density, driven by a 40TW laser, demonstrating the anticipated scaling to higher beam energies. Particle simulations indicate that the low energy spread beams wereproduced from self trapped electrons through the interplay of trapping, loading, and dephasing. Other experiments and simulations are alsounderway to control injection of particles into the wake, and henceimprove beam quality and stability further.
Download or read book Energy Doubling of 42 GeV Electrons in a Meter scale Plasma Wakefield Accelerator written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant energy gain. Here we show that an energy gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of (almost equal to) 52GV m−1. This effectively doubles their energy, producing the energy gain of the 3-km-long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. This is an important step towards demonstrating the viability of plasma accelerators for high-energy physics applications.
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 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.
Download or read book Superstrong Fields in Plasmas written by and published by . This book was released on 2002 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Generation and Optimization of High Quality Multi GeV Electron Beams in Plasma Wakefield Accelerators written by Thamine Dalichaouch and published by . This book was released on 2021 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, a new method for producing ultra-bright electron beams in nonlinear plasma wave wakes driven by an electron beam driver is explored using particle-in-cell simulations and analytic theory. In order to understand this process an accurate description of a nonlinear wakefield is required. These nonlinear wakefields are excited by intense particle beams or lasers pushing plasma electrons radially outward, creating an ion bubble surrounded by a sheath of electrons characterized by the source term $S \equiv -\frac{1}{en_p}(\rho-J_z/c)$, where $e$ is the electron charge, $n_p$ is the plasma number density, $\rho$ is the charge density, and $J_z$ is the axial current density. Previously, the sheath source term was described phenomenologically with a positive-definite function thereby resulting in a positive definite wake potential. In reality, the wake potential is negative at the rear of the ion column, which is important for self-injection and accurate beam loading models. To account for this, in the first part of this dissertation a multi-sheath model in which the source term, $S$, of the plasma wake can be negative in regions outside the ion bubble is introduced. Using this model, a new expression for the wake potential and a modified differential equation for the bubble radius is obtained. Numerical results obtained from these equations are validated against particle-in-cell simulations for unloaded and loaded wakes. The new model provides accurate predictions of the shape and duration of trailing bunch current profiles that flatten plasma wakefields. It is also used to design a trailing bunch for a desired longitudinally varying loaded wakefield. The multi-sheath model is also applied to beam loading in laser wakefields. Areas where the multi-sheath model can be improved for laser drivers in future work are discussed. In the second part of this dissertation, a new method of controllable injection to generate high quality electron bunches in the nonlinear blowout regime driven by electron beams is proposed and demonstrated using particle-in-cell simulations. Injection is facilitated by decreasing the wake phase velocity through focusing the drive beam spot size. Two regimes are examined. In the first, the spot size is focused according to the vacuum Courant-Snyder (CS) beta function while, in the second, it is self-focused by the plasma ion column. The effects of the driver intensity and vacuum CS parameters on the wake velocity and injected beam parameters are examined via theory and simulations. For plasma densities of $\sim 10^{19} ~\centi\meter^{-3}$, particle-in-cell (PIC) simulations demonstrate that peak normalized brightnesses $\gtrsim 10^{20}~\ampere/\meter^2/\rad^2$ can be obtained with projected energy spreads of $\lesssim 1\%$ within the middle section of the injected beam and with normalized slice emittances as low as $\sim 10 ~\nano\meter$. In the last part of the dissertation, a predictive model for injection using the self-evolving driver method in the plasma focusing regime is developed. The model is used to characterize how the wake evolution and final injected beam parameters scale with the driver parameters. Parameter scans of PIC simulations using different drivers are performed and compared with the model predictions. In particular, the dependence of the injected beam parameters with the diffraction length, energy, intensity, spot size, and duration of the driver is examined. It is found that injection and optimal beam loading can be simultaneously achieved. The multi-sheath model is also used to study the beam loading effects from the injected bunch in this case. PIC simulation results indicate that the injected beam can be efficiently accelerated to $18.27$ GeV with a projected energy spread of $ 0.49\%$ and peak normalized brightess of $B_n \sim 10^{20}~\ampere/\meter^2/\rad^2$ for a plasma density of $\sim 10^{19} ~\centi\meter^{-3}$.
Download or read book GeV Electron Beams from a Capillary Discharge Guided Laser Plasma Accelerator written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser plasma acceleration (LPA) up to 1 GeV has been realized at Lawrence Berkeley National Laboratory by using a capillary discharge waveguide. In this paper, the capillary discharge guided LPA system including a broadband single-shot electron spectrometer is described. The spectrometer was designed specifically for LPA experiments and has amomentumacceptance of 0.01 - 1.1 GeV/c with a percent level resolution. Experiments using a 33 mm long, 300 mu m diameter capillary demonstrated the generation of high energy electron beams up to 1 GeV. By de-tuning discharge delay from optimum guiding performance, selftrapping and acceleration were found to be stabilized producing 460 MeV electron beams.
Download or read book Classical and Quantum Description of Plasma and Radiation in Strong Fields written by Fabien Niel and published by Springer Nature. This book was released on 2021-05-06 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents several important aspects of the plasma dynamics in extremely high intensity electromagnetic fields when quantum electrodynamics effects have to be taken into account. This work is of utmost importance for the forthcoming generation of multipetawatt laser facilities where this physics will be tested. The first part consists of an introduction that extends from classical and quantum electrodynamics in strong fields to the kinetic description of plasmas in the interaction with such fields. This can be considered as an advanced tutorial which would be extremely useful to researchers and students new to the field. The second part describes original contributions on the analysis of the signatures of classical and quantum radiation reaction on the distribution function of the charged particles and of the photon spectrum, and leads to significant advances on this topic. These results are then extended to the analysis of the so-called QED cascades which are of central importance for a better understanding of some astrophysical phenomena and basic physics problems. Finally, the book discusses future directions for the high intensity laser–plasma interaction community. The results presented in this thesis are expected to become more and more relevant as the new multipetawatt facilities become operative.
Download or read book High Quality Electron Bunches Up to 1 GeV from Laser WakefieldAcceleration at LBNL written by C. B. Schroeder and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments at the LOASIS laboratory of LBNL havedemonstrated production of 100 MeV to 1 GeV electron bunches with lowenergy spread and low divergence from laser wakefield acceleration. Theradiation pressure of a 10 TW laser pulse, guided over 10 diffractionranges by a few-mm long plasma density channel, was used to drive anintense plasma wave (wakefield), producing electron bunches with energieson the order of 100 MeV and acceleration gradients on the order of 100GV/m. Beam energy was increased from 100 MeV to 1 GeV by using a few-cmlong guiding channel at lower density, driven by a 40 TW laser, demonstrating the anticipated scaling to higher beam energies. Particlesimulations indicate that the low energy spread beams were produced fromself-trapped electrons through the interplay of trapping, loading, anddephasing. Other experiments and simulations are also underway to controlinjection of particles into the wake, and hence improve beam quality andstability further.
Download or read book Superstrong Fields in Plasmas written by Istituto di fisica del plasma (Italy) and published by American Institute of Physics. This book was released on 2002-04-12 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few years, laser intensities have dramatically increased. Today, relatively compact laser systems can produce on target intensities four to five orders of magnitude greater than was previously possible. During this conference, the most recent theoretical and experimental advances in several fields of basic physics and of the relevant technological applications, made possible by the rapid development of such superstrong lasers, were presented and discussed. In the present volume the reader will find general and technical contributions on topics such as atomic and molecular dynamics in strong fields, high harmonic generation, coherent X-ray radiation, nonlinear plasma dynamics and relativistic optics, ultrarelativistic particle production and acceleration, inertial confinement fusion and fast ignition, laboratory astrophysics, high energy astrophysics and cosmology, applications of superstrong pulses to high energy physics.
