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Author :
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ISBN 13 :
Total Pages : 3 pages
Book Rating : 4.:/5 (958 download)
Download or read book Preliminary Simulations of Plasma Wakefield Accelerator Experiments at FACET. written by and published by . This book was released on 2016 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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ISBN 13 :
Total Pages : 3 pages
Book Rating : 4.:/5 (873 download)
Download or read book Plasma Wakefield Experiments at FACET. written by and published by . This book was released on 2011 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to ≈20[mu]m long and focused to ≈10[mu]m wide. The intense fields of the FACET bunches will be used to field ionize neutral lithium or cesium vapor produced in a heat pipe oven. Previous experiments at the SLAC FFTB facility demonstrated 50GeV/m gradients in an 85cm field ionized lithium plasma where the interaction distance was limited by head erosion. Simulations indicate the lower ionization potential of cesium will decrease the rate of head erosion and increase single stage performance. The initial experimental program will compare the performance of lithium and cesium plasma sources with single and double bunches. Later experiments will investigate improved performance with a pre-ionized cesium plasma. The status of the experiments and expected performance are reviewed. The FACET Facility is being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The facility will begin commissioning in summer 2011 and conduct an experimental program over the coming five years to study electron and positron beam driven plasma acceleration with strong wake loading in the non-linear regime. The FACET experiments aim to demonstrate high-gradient acceleration of electron and positron beams with high efficiency and negligible emittance growth.
Author : M. J. Hogan
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (316 download)
Download or read book 3-D Simulations of Plasma Wakefield Acceleration with Non-Idealized Plasmas and Beams written by M. J. Hogan and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 3-D Particle-in-cell OSIRIS simulations of the current E-162 Plasma Wakefield Accelerator Experiment are presented in which a number of non-ideal conditions are modeled simultaneously. These include tilts on the beam in both planes, asymmetric beam emittance, beam energy spread and plasma inhomogeneities both longitudinally and transverse to the beam axis. The relative importance of the non-ideal conditions is discussed and a worst case estimate of the effect of these on energy gain is obtained. The simulation output is then propagated through the downstream optics, drift spaces and apertures leading to the experimental diagnostics to provide insight into the differences between actual beam conditions and what is measured. The work represents a milestone in the level of detail of simulation comparisons to plasma experiments.
Download or read book Results From Plasma Wakefield Acceleration Experiments at FACET. written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Xinlu Xu
Publisher : Springer Nature
ISBN 13 : 9811523819
Total Pages : 138 pages
Book Rating : 4.8/5 (115 download)
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.
Author : Weiming An
Publisher :
ISBN 13 :
Total Pages : 159 pages
Book Rating : 4.:/5 (868 download)
Download or read book Efficient Modeling of Plasma Wake Field Acceleration Experiments Using Particle-in-cell Methods written by Weiming An and published by . This book was released on 2013 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is no clear path for building a particle accelerator at the energy frontier beyond the Large Hadron Collider (LHC). One option that is receiving attention is to use plasma wave wakefields driven by intense particle beams. Recent experiments conducted at the Stanford Linear Accelerator Center (SLAC) show that accelerating gradients in such wakefields in excess of 50 GeV/m can be sustained over meter scales. Based on this, a linear collider concept of staging one-meter long plasma cells together has been proposed. A facility at SLAC has been built to study the physics in one stage. In this dissertation we describe improvements and enhancements to a highly efficient simulation model for simulating current experiments at SLAC as well as parameters beyond the reach of current experiments. The model is the quasi-static particle-in-cell (PIC) code QuickPIC. A modified set of quasi-static field equations were developed, which reduced the number of predictor corrector iteration loops and an improved source deposit scheme was developed to reduce the parallel communication. These improvements led to a factor of 5 to 8 (depending on the simulation parameters) speedup compared with the previous set of field equations and deposition scheme. Several new modules were also added to QuickPIC, including the multiple field ionization and improved beam and plasma particle diagnostics. We also used QuickPIC to study the optimum plasma density for maximizing the acceleration field for fixed electron beam parameters. QuickPIC simulations were also used to study and design two-bunch PWFA experiments at SLAC including methods for mitigating the ionization-induced beam head erosion. The mitigation methods can enhance the energy gain in two-bunch PWFA experiments at SLAC by a factor of 10 for the same beam parameters. For beam parameters beyond SLAC but perhaps necessary for a future collider, QuickPIC was used to study how the ultra high electric fields of a tightly focused second electron bunch could lead to ion motion, which disrupts the focusing fields on the second bunch. The resulting nonlinearity in the transverse focusing force of the plasma wake will lead to emittance growth. We used QuickPIC to carry out the first fully self-consistent high resolution simulation on the effects of ion motion for PWFA linear collider problems. Preliminary results showed that the plasma-ion-motion-induced emittance growth was limited to less than a factor of 2. In addition to the electron beam driven PWFA, we also study how a short proton beam can excite a large plasma wake. Such short proton beams are currently not experimentally available. We therefore also study how long proton beams such as those at Fermi National Laboratory and CERN may drive a large plasma wake through a self-modulation instability. A linear theory for the self-modulation instability is presented under the wide beam limit. QuickPIC simulations show that the self-modulation of a long proton beam in a plasma may lead to the micro-bunching of the beam and excite a large plasma wake.
Author : Yujian Zhao
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (137 download)
Download or read book Emittance Preservation in a Plasma Wakefield Accelerator written by Yujian Zhao and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma-based acceleration (PBA) is being considered as the basis for a future linear collider,where electrons and positron bunches must collide with extremely small spot sizes. In order to be focused to such spot sizes the beams must have extremely small emittances. Thus one challenge to a PBA collider is preserving the emittance of the accelerated beams. In this dissertation, the evolution and preservation of the witness beam emittance in aplasma-based accelerator in the nonlinear blowout regime is investigated using theory and particle-in-cell simulations. It it found that the use of plasma density ramps as matching sections are beneficial for emittance emittance growth mitigation and preservation even when the witness beam is focused so tightly within the plasma that its space charge force pulls ions inwards within the beam. In order to study the evolution of a beam in the wakefield, details of the motion ofa single beam particle in the accelerating and focusing fields of a nonlinear wakefield are presented. The exact solution to the transverse equation of motion of a single beam particle under the assumption of adiabatic acceleration is derived. Approximate and thus simpler solutions are provided under the assumptions that plasma density also changes adiabatically. Some important concepts, including the beam's envelope equation, geometric emittance, normalized emittance, single and beam C-S parameters, transport matrices, and matching are reviewed and elaborated upon. Emittance evolution and the importance of matching are discussed in the context of a uniform plasma. Using the approximate solution (WKB solution) of a single particle's motion, analyticalexpressions for the evolution of the beam emittance and the C-S parameters in an arbitrary adiabatic plasma profile are provided neglecting the acceleration of the beam inside the plasma. It is shown that the beam emittance can be preserved when the beams C-S parameters are matched to the entrance of the density profile even when the beam has an initial energy spread. It is also shown that the emittance growth for an unmatched beam is minimized when it is focused to the same vacuum plane as for a matched beam. The emittance evolution without ion motion is studied using 3D particle-in-cell QuickPIC simulation and the results agree well with the theoretical predictions. In some of the proposed experiments for the recently commissioned FACET II facility,the matching condition may not be perfectly satisfied and the wake may not be perfectly symmetric. It is shown that for a given set of beam parameters that are consistent with FACET II capabilities, the emittance growth can still be minimized by choosing the optimal focal plane even when the assumptions of the theory are not satisfied. Additional considerations for FACET II experiments were investigated. The plasma source is a lithium plasma confined by a helium buffer gas. The plasma is formed from field ionization which can lead to a nonlinear focusing force inside the helium buffer gas due to its high ionization potential leading to a nonuniform transverse profile for the plasma. It is found in simulations that for an initial beam emittance of 20 [mu]m, the helium ionization is found to be small and the witness beam's emittance can still be preserved. Emittance evolution for beam and plasma parameters relevant to a single stage of amulti-staged plasma-based linear collider (LC) is investigated. In some plasma-based LC designs the transverse space charge forces for extreme accelerating beam parameters are expected to pull background ions into the beam which can lead to longitudinally varying nonlinear focusing forces and result in emittance growth of the beam. To mitigate this, the use of an adiabatic plasma density ramp as a matching section is proposed and examined using theory and PIC simulations. The witness beam is matched to the low density plasma entrance, where the beam initially has a large matched spot size so the ion motion effects are relatively small. As the beam propagates in the plasma density upramp (downramp), it is adiabatically focused (defocused) and its phase space distribution evolves slowly towards an equilibrium distribution including the effects of the adiabatically changing ion motion. Simulation results from QPAD, a new quasi-3D, quasi-static PIC code, show that within a single acceleration stage, this concept can limit the projected emittance growth to only ∼2% for a 25 GeV, 100 nm emittance witness beam and ∼20% for a 100 GeV, 100 nm emittance witness beam. The trade-off between the adiabaticity of the plasma density ramp and the initial ion motion at the entrance for a given length of the plasma density ramp is also discussed. Additional issues for building a plasma based linear collider are discussed. Preliminaryparticle-in-cell simulation results which examine and illustrate problems like staging, shaped witness beam (for improved beam loading), emittance growth and hosing of a witness beam with an initial offset, ion motion triggered by the driver, and asymmetric witness beams are presented. The implications of these issues on a plasma based linear collider are discussed. Simulation results for witness beams with initial energy of 500 GeV such as would exist in a final stage of a PBA linear collider or an afterburner are presented.
Download or read book Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC. written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators. FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.
Author : Navid Vafaei-Najafabadi
Publisher :
ISBN 13 :
Total Pages : 156 pages
Book Rating : 4.:/5 (17 download)
Download or read book Experimental Investigations of Beam Driven Plasma Wakefield Accelerators written by Navid Vafaei-Najafabadi and published by . This book was released on 2016 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: A plasma wakefield accelerator (PWFA) uses a plasma wave (a wake) to accelerate electrons at a gradient that is three orders of magnitude higher than that of a conventional accelerator. When the plasma wave is driven by a high-density particle beam or a high-intensity laser pulse, it evolves into the nonlinear blowout regime, where the driver expels the background plasma electrons, resulting in an ion cavity forming behind the driver. This ion cavity has ideal properties for accelerating and focusing electrons. One method to insert electrons into this highly-relativistic, transient structure is by ionization injection. In this method, electrons resulting from further ionization of the ions inside the wake are trapped and accelerated by the wakefield. These injected electrons absorb the energy of the wake, resulting in a reduced accelerating field amplitude; this phenomenon is known as beam loading. This thesis discusses experiments that demonstrate how ionization injection can, on the one hand, lead to excessive beam loading and be a detriment to a PWFA, while on the other hand, it may be taken advantage of to produce bright electron beams that will be necessary for applications of a PWFA to a free electron laser (FEL) or a collider. These experiments were part of the FACET Campaign at the SLAC National Accelerator Laboratory and used FACET's 3 nC, 20.35 GeV electron beam to field ionize the plasma source and drive a wake. In the first experiment, the plasma source was a 30 cm column of rubidium (Rb) vapor. The low ionization potential and high atomic mass of Rb made it a suitable candidate as a plasma source for a PWFA. However, the low ionization potential of the Rb+ ion resulted in continuous ionization of Rb+ and injection of electrons along the length of the plasma. This resulted in heavy beam-loading, which reduced the strength of the accelerating field by half, making the Rb source unusable for a PWFA. In the second experiment, the plasma source was a column of lithium (Li) vapor bound by cold helium (He) gas. Here, the ionization injection of He electrons in the 10 cm boundary region between Li and He led to localized beam loading and resulted in an accelerated electron beam with high energy (32 GeV), a 10% energy spread, and an emittance an order of magnitude smaller than the drive beam. Particle-in-cell simulations indicate that the beam loading can be further optimized by reducing the injection region even more, which can lead to bright, high-current, low-energy-spread electron beams.
Download or read book E-157 written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the E-157 experiment now being conducted at the Stanford Linear Accelerator Center (SLAC), a 30 GeV electron beam of 2 x 101° electrons in a 0.65mm long bunch is propagated through a 1.4m long Lithium plasma of density up to 2 x 1014 e−/cm3. The initial beam density is greater than the plasma density, and the head of the bunch expels the plasma electrons leaving behind a uniform ion channel with transverse focusing fields of up to several thousand Tesla/m. The initial transverse beam size with sigma = 50--100 mu-m is larger than the matched size of 5 mu-m resulting in up to three beam envelope oscillations within the plasma. Time integrated optical transition radiation (OTR) is used to study the transverse beam profile immediately before and after the plasma to characterize the transverse beam dynamics as a function of plasma density. The head of the bunch deposits energy into plasma wakes, resulting in longitudinal accelerating fields which are witnessed by the tail of the same bunch. A time-resolved Cherenkov imaging system is located in an energy dispersive plane downstream of the plasma. It images the beam onto a streak camera allowing time-resolved measurements of the beam energy spectrum as a function of plasma density. Preliminary experimental data from the first three runs are compared to theory and computer simulations.
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Publisher :
ISBN 13 :
Total Pages : 3 pages
Book Rating : 4.:/5 (685 download)
Download or read book Modeling Self-Ionized Plasma Wakefield Acceleration for Afterburner Parameters Using QuickPIC. written by and published by . This book was released on 2006 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the parameters envisaged in possible afterburner stages[1] of a plasma wakefield accelerator (PWFA), the self-fields of the particle beam can be intense enough to tunnel ionize some neutral gases. Tunnel ionization has been investigated as a way for the beam itself to create the plasma, and the wakes generated may differ from those generated in pre-ionized plasmas[2], [3]. However, it is not practical to model the whole stage of PWFA with afterburner parameters using the models described in [2] and [3]. Here we describe the addition of a tunnel ionization package using the ADK model into QuickPIC, a highly efficient quasi-static particle in cell (PIC) code which can model a PWFA with afterburner parameters. Comparison between results from OSIRIS (a full PIC code with ionization) and from QuickPIC with the ionization package shows good agreement. Preliminary results using parameters relevant to the E164X experiment and the upcoming E167 experiment at SLAC are shown.
Author : Yangmei Li
Publisher : Springer Nature
ISBN 13 : 3030501167
Total Pages : 140 pages
Book Rating : 4.0/5 (35 download)
Download or read book Studies of Proton Driven Plasma Wakefield Acceleration written by Yangmei Li and published by Springer Nature. This book was released on 2020-07-15 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on a cutting-edge area of research, which is aligned with CERN's mainstream research, the "AWAKE" project, dedicated to proving the capability of accelerating particles to the energy frontier by the high energy proton beam. The author participated in this project and has advanced the plasma wakefield theory and modelling significantly, especially concerning future plasma acceleration based collider design. The thesis addresses electron beam acceleration to high energy whilst preserving its high quality driven by a single short proton bunch in hollow plasma. It also demonstrates stable deceleration of multiple proton bunches in a nonlinear regime with strong resonant wakefield excitation in hollow plasma, and generation of high energy and high quality electron or positron bunches. Further work includes the assessment of transverse instabilities induced by misaligned beams in hollow plasma and enhancement of the wakefield amplitude driven by a self-modulated long proton bunch with a tapered plasma. This work has major potential to impact the next generation of linear colliders and also in the long-term may help develop compact accelerators for use in industrial and medical facilities.
Author :
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ISBN 13 :
Total Pages : 4 pages
Book Rating : 4.:/5 (925 download)
Download or read book Latest Plasma Wakefield Acceleration Results from the FACET Project written by and published by . This book was released on 2014 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Kieran Hanahoe
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (16 download)
Download or read book Simulation Studies of Plasma Wakefield Acceleration written by Kieran Hanahoe and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 14 pages
Book Rating : 4.:/5 (962 download)
Download or read book Experimental, Theoretical and Computational Studies of Plasma-Based Concepts for Future High Energy Accelerators written by and published by . This book was released on 2013 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the final report on the DOE grant number DE-FG02-92ER40727 titled, "Experimental, Theoretical and Computational Studies of Plasma-Based Concepts for Future High Energy Accelerators." During this grant period the UCLA program on Advanced Plasma Based Accelerators, headed by Professor C. Joshi has made many key scientific advances and trained a generation of students, many of whom have stayed in this research field and even started research programs of their own. In this final report however, we will focus on the last three years of the grant and report on the scientific progress made in each of the four tasks listed under this grant. Four tasks are focused on: Plasma Wakefield Accelerator Research at FACET, SLAC National Accelerator Laboratory, In House Research at UCLA's Neptune and 20 TW Laser Laboratories, Laser-Wakefield Acceleration (LWFA) in Self Guided Regime: Experiments at the Callisto Laser at LLNL, and Theory and Simulations. Major scientific results have been obtained in each of the four tasks described in this report. These have led to publications in the prestigious scientific journals, graduation and continued training of high quality Ph. D. level students and have kept the U.S. at the forefront of plasma-based accelerators research field.
Author :
Publisher :
ISBN 13 :
Total Pages : 5 pages
Book Rating : 4.:/5 (727 download)
Download or read book Particle-in-cell Simulations of Plasma Accelerators and Electron-neutral Collisions written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present 2-D simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented particle-in-cell code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ((almost equal to)1016 W/cm2) and high ((almost equal to)1018 W/cm2) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory and fluid simulations. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications of XOOPIC required by this work, and summarize the issues relevant to modeling relativistic electron-neutral collisions in a particle-in-cell code.
Download or read book Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, [epsilon]{sub N, x}/I{sub t}, below the level of 0.2 [mu]m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of [epsilon]{sub N, x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few [mu]m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped electron bunches. Chapters four and five present the experimental diagnostics and measurements for the trapped electrons. Next, the sixth chapter introduces suggestions for future trapped electron experiments. Then, Chapter seven contains the conclusions. In addition, there is an appendix chapter that covers a topic which is extraneous to electron trapping, but relevant to the PWFA. This chapter explores the feasibility of one idea for the production of a hollow channel plasma, which if produced could solve some of the remaining issues for a plasma-based collider.
