1
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Wu YP, Hua JF, Zhou Z, Zhang J, Liu S, Peng B, Fang Y, Nie Z, Ning XN, Pai CH, Du YC, Lu W, Zhang CJ, Mori WB, Joshi C. Phase Space Dynamics of a Plasma Wakefield Dechirper for Energy Spread Reduction. Phys Rev Lett 2019; 122:204804. [PMID: 31172777 DOI: 10.1103/physrevlett.122.204804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 04/19/2019] [Indexed: 06/09/2023]
Abstract
Plasma-based accelerators have made impressive progress in recent years. However, the beam energy spread obtained in these accelerators is still at the ∼1% level, nearly one order of magnitude larger than what is needed for challenging applications like coherent light sources or colliders. In plasma accelerators, the beam energy spread is mainly dominated by its energy chirp (longitudinally correlated energy spread). Here we demonstrate that when an initially chirped electron beam from a linac with a proper current profile is sent through a low-density plasma structure, the self-wake of the beam can significantly reduce its energy chirp and the overall energy spread. The resolution-limited energy spectrum measurements show at least a threefold reduction of the beam energy spread from 1.28% to 0.41% FWHM with a dechirping strength of ∼1 (MV/m)/(mm pC). Refined time-resolved phase space measurements, combined with high-fidelity three-dimensional particle-in-cell simulations, further indicate the real energy spread after the dechirper is only about 0.13% (FWHM), a factor of 10 reduction of the initial energy spread.
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Affiliation(s)
- Y P Wu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - J F Hua
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Z Zhou
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - J Zhang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - S Liu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - B Peng
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y Fang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Z Nie
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - X N Ning
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C-H Pai
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y C Du
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C J Zhang
- University of Los Angeles, Los Angeles, California 90095, USA
| | - W B Mori
- University of Los Angeles, Los Angeles, California 90095, USA
| | - C Joshi
- University of Los Angeles, Los Angeles, California 90095, USA
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2
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Wan Y, Pai CH, Zhang CJ, Li F, Wu YP, Hua JF, Lu W, Joshi C, Mori WB, Malka V. Physical mechanism of the electron-ion coupled transverse instability in laser pressure ion acceleration for different regimes. Phys Rev E 2018; 98:013202. [PMID: 30110864 DOI: 10.1103/physreve.98.013202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Indexed: 06/08/2023]
Abstract
In radiation pressure ion acceleration (RPA) research, the transverse stability within laser plasma interaction has been a long-standing, crucial problem over the past decades. In this paper, we present a one-dimensional two-fluid theory extended from a recent work Wan et al. Phys. Rev. Lett. 117, 234801 (2016)PRLTAO0031-900710.1103/PhysRevLett.117.234801 to clearly clarify the origin of the intrinsic transverse instability in the RPA process. It is demonstrated that the purely growing density fluctuations are more likely induced due to the strong coupling between the fast oscillating electrons and quasistatic ions via the ponderomotive force with spatial variations. The theory contains a full analysis of both electrostatic (ES) and electromagnetic modes and confirms that the ES mode actually dominates the whole RPA process at the early linear stage. By using this theory one can predict the mode structure and growth rate of the transverse instability in terms of a wide range of laser plasma parameters. Two-dimensional particle-in-cell simulations are systematically carried out to verify the theory and formulas in different regimes, and good agreements have been obtained, indicating that the electron-ion coupled instability is the major factor that contributes the transverse breakup of the target in RPA process.
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Affiliation(s)
- Y Wan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - C-H Pai
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C J Zhang
- University of California-Los Angeles, Los Angeles, California 90095, USA
| | - F Li
- University of California-Los Angeles, Los Angeles, California 90095, USA
| | - Y P Wu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - J F Hua
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C Joshi
- University of California-Los Angeles, Los Angeles, California 90095, USA
| | - W B Mori
- University of California-Los Angeles, Los Angeles, California 90095, USA
| | - V Malka
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
- Laboratoire d'Optique Appliquée, ENSTA-CNRS-Ecole Polytechnique, UMR7639, 91761 Palaiseau, France
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3
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Zhang CJ, Hua JF, Wan Y, Pai CH, Guo B, Zhang J, Ma Y, Li F, Wu YP, Chu HH, Gu YQ, Xu XL, Mori WB, Joshi C, Wang J, Lu W. Femtosecond Probing of Plasma Wakefields and Observation of the Plasma Wake Reversal Using a Relativistic Electron Bunch. Phys Rev Lett 2017; 119:064801. [PMID: 28949606 DOI: 10.1103/physrevlett.119.064801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Indexed: 06/07/2023]
Abstract
We show that a high-energy electron bunch can be used to capture the instantaneous longitudinal and transverse field structures of the highly transient, microscopic, laser-excited relativistic wake with femtosecond resolution. The spatiotemporal evolution of wakefields in a plasma density up ramp is measured and the reversal of the plasma wake, where the wake wavelength at a particular point in space increases until the wake disappears completely only to reappear at a later time but propagating in the opposite direction, is observed for the first time by using this new technique.
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Affiliation(s)
- C J Zhang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
| | - J F Hua
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y Wan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C-H Pai
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - B Guo
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - J Zhang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y Ma
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - F Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y P Wu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - H-H Chu
- Department of Physics, National Central University, Jhong-Li 32001, Taiwan
| | - Y Q Gu
- Science and Technology on Plasma Physics Laboratory, Laser Fusion Research Center, CAEP, Mianyang 621900, China
| | - X L Xu
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - W B Mori
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - C Joshi
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
| | - J Wang
- Department of Physics, National Central University, Jhong-Li 32001, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- IFSA Collaborative Center, Shanghai Jiao Tong University, Shanghai 200240, China
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4
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Wan Y, Pai CH, Zhang CJ, Li F, Wu YP, Hua JF, Lu W, Gu YQ, Silva LO, Joshi C, Mori WB. Physical Mechanism of the Transverse Instability in Radiation Pressure Ion Acceleration. Phys Rev Lett 2016; 117:234801. [PMID: 27982647 DOI: 10.1103/physrevlett.117.234801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Indexed: 06/06/2023]
Abstract
The transverse stability of the target is crucial for obtaining high quality ion beams using the laser radiation pressure acceleration (RPA) mechanism. In this Letter, a theoretical model and supporting two-dimensional (2D) particle-in-cell (PIC) simulations are presented to clarify the physical mechanism of the transverse instability observed in the RPA process. It is shown that the density ripples of the target foil are mainly induced by the coupling between the transverse oscillating electrons and the quasistatic ions, a mechanism similar to the oscillating two stream instability in the inertial confinement fusion research. The predictions of the mode structure and the growth rates from the theory agree well with the results obtained from the PIC simulations in various regimes, indicating the model contains the essence of the underlying physics of the transverse breakup of the target.
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Affiliation(s)
- Y Wan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - C-H Pai
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C J Zhang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - F Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y P Wu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - J F Hua
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Y Q Gu
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China
| | - L O Silva
- GoLP/instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - C Joshi
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - W B Mori
- University of California Los Angeles, Los Angeles, California 90095, USA
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5
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Xu XL, Pai CH, Zhang CJ, Li F, Wan Y, Wu YP, Hua JF, Lu W, An W, Yu P, Joshi C, Mori WB. Nanoscale Electron Bunching in Laser-Triggered Ionization Injection in Plasma Accelerators. Phys Rev Lett 2016; 117:034801. [PMID: 27472116 DOI: 10.1103/physrevlett.117.034801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 06/06/2023]
Abstract
Ionization injection is attractive as a controllable injection scheme for generating high quality electron beams using plasma-based wakefield acceleration. Because of the phase-dependent tunneling ionization rate and the trapping dynamics within a nonlinear wake, the discrete injection of electrons within the wake is nonlinearly mapped to a discrete final phase space structure of the beam at the location where the electrons are trapped. This phenomenon is theoretically analyzed and examined by three-dimensional particle-in-cell simulations which show that three-dimensional effects limit the wave number of the modulation to between >2k_{0} and about 5k_{0}, where k_{0} is the wave number of the injection laser. Such a nanoscale bunched beam can be diagnosed by and used to generate coherent transition radiation and may find use in generating high-power ultraviolet radiation upon passage through a resonant undulator.
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Affiliation(s)
- X L Xu
- University of California, Los Angeles, California 90095, USA
| | - C-H Pai
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C J Zhang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - F Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y Wan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y P Wu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - J F Hua
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - W An
- University of California, Los Angeles, California 90095, USA
| | - P Yu
- University of California, Los Angeles, California 90095, USA
| | - C Joshi
- University of California, Los Angeles, California 90095, USA
| | - W B Mori
- University of California, Los Angeles, California 90095, USA
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6
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Zhang CJ, Hua JF, Xu XL, Li F, Pai CH, Wan Y, Wu YP, Gu YQ, Mori WB, Joshi C, Lu W. Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe. Sci Rep 2016; 6:29485. [PMID: 27403561 PMCID: PMC4939525 DOI: 10.1038/srep29485] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/20/2016] [Indexed: 11/15/2022] Open
Abstract
A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.
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Affiliation(s)
- C J Zhang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China.,Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.,IFSA Collaborative Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - J F Hua
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - X L Xu
- University of California, Los Angeles, California 90095, USA
| | - F Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C-H Pai
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y Wan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y P Wu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y Q Gu
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China
| | - W B Mori
- University of California, Los Angeles, California 90095, USA
| | - C Joshi
- University of California, Los Angeles, California 90095, USA
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China.,IFSA Collaborative Center, Shanghai Jiao Tong University, Shanghai 200240, China
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7
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Xu XL, Hua JF, Wu YP, Zhang CJ, Li F, Wan Y, Pai CH, Lu W, An W, Yu P, Hogan MJ, Joshi C, Mori WB. Physics of Phase Space Matching for Staging Plasma and Traditional Accelerator Components Using Longitudinally Tailored Plasma Profiles. Phys Rev Lett 2016; 116:124801. [PMID: 27058082 DOI: 10.1103/physrevlett.116.124801] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Indexed: 06/05/2023]
Abstract
Phase space matching between two plasma-based accelerator (PBA) stages and between a PBA and a traditional accelerator component is a critical issue for emittance preservation. The drastic differences of the transverse focusing strengths as the beam propagates between stages and components may lead to a catastrophic emittance growth even when there is a small energy spread. We propose using the linear focusing forces from nonlinear wakes in longitudinally tailored plasma density profiles to control phase space matching between sections with negligible emittance growth. Several profiles are considered and theoretical analysis and particle-in-cell simulations show how these structures may work in four different scenarios. Good agreement between theory and simulation is obtained, and it is found that the adiabatic approximation misses important physics even for long profiles.
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Affiliation(s)
- X L Xu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- University of California, Los Angeles, California 90095, USA
| | - J F Hua
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y P Wu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C J Zhang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - F Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y Wan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C-H Pai
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - W An
- University of California, Los Angeles, California 90095, USA
| | - P Yu
- University of California, Los Angeles, California 90095, USA
| | - M J Hogan
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C Joshi
- University of California, Los Angeles, California 90095, USA
| | - W B Mori
- University of California, Los Angeles, California 90095, USA
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8
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Xu XL, Hua JF, Li F, Zhang CJ, Yan LX, Du YC, Huang WH, Chen HB, Tang CX, Lu W, Yu P, An W, Joshi C, Mori WB. Phase-space dynamics of ionization injection in plasma-based accelerators. Phys Rev Lett 2014; 112:035003. [PMID: 24484147 DOI: 10.1103/physrevlett.112.035003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Indexed: 06/03/2023]
Abstract
The evolution of beam phase space in ionization injection into plasma wakefields is studied using theory and particle-in-cell simulations. The injection process involves both longitudinal and transverse phase mixing, leading initially to a rapid emittance growth followed by oscillation, decay, and a slow growth to saturation. An analytic theory for this evolution is presented and verified through particle-in-cell simulations. This theory includes the effects of injection distance (time), acceleration distance, wakefield structure, and nonlinear space charge forces, and it also shows how ultralow emittance beams can be produced using ionization injection methods.
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Affiliation(s)
- X L Xu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - J F Hua
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - F Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C J Zhang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - L X Yan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Y C Du
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - W H Huang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - H B Chen
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - C X Tang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China and University of California Los Angeles, Los Angeles, California 90095, USA
| | - P Yu
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - W An
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - C Joshi
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - W B Mori
- University of California Los Angeles, Los Angeles, California 90095, USA
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9
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Li F, Hua JF, Xu XL, Zhang CJ, Yan LX, Du YC, Huang WH, Chen HB, Tang CX, Lu W, Joshi C, Mori WB, Gu YQ. Generating high-brightness electron beams via ionization injection by transverse colliding lasers in a plasma-wakefield accelerator. Phys Rev Lett 2013; 111:015003. [PMID: 23863007 DOI: 10.1103/physrevlett.111.015003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Indexed: 06/02/2023]
Abstract
The production of ultrabright electron bunches using ionization injection triggered by two transversely colliding laser pulses inside a beam-driven plasma wake is examined via three-dimensional particle-in-cell simulations. The relatively low intensity lasers are polarized along the wake axis and overlap with the wake for a very short time. The result is that the residual momentum of the ionized electrons in the transverse plane of the wake is reduced, and the injection is localized along the propagation axis of the wake. This minimizes both the initial thermal emittance and the emittance growth due to transverse phase mixing. Simulations show that ultrashort (~8 fs) high-current (0.4 kA) electron bunches with a normalized emittance of 8.5 and 6 nm in the two planes, respectively, and a brightness of 1.7×10(19) A rad(-2) m(-2) can be obtained for realistic parameters.
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Affiliation(s)
- F Li
- Key Laboratory of Particle and Radiation Imaging of Ministry of Education, Tsinghua University, Beijing 100084, China
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10
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Wang D, Yan LX, Du YC, Hua JF, Du Q, Qian HJ, Lu XH, Huang WH, Chen HB, Tang CX. Generating ultrabroadband terahertz radiation based on the under-compression mode of velocity bunching. Rev Sci Instrum 2013; 84:022704. [PMID: 23464186 DOI: 10.1063/1.4790430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We propose and analyze a scheme to generate enhanced ultrabroadband terahertz (THz) radiation through coherent transition radiation emitted by ultrashort electron beams based on a 10.5 m beamline at Tsinghua University. The proposed scheme involves the initial compression of the electron beam with a few hundred pC charges using a velocity bunching scheme (i.e., RF compression) in an under-compression mode instead of the usual critical-compression mode in order to maintain a positive energy chirp at the exit of the traveling wave accelerator. After a long drift segment, the particles in the tail catch up with the bunch head. More than 80% of the particles are distributed in a spike with an rms length less than 20 fs. Such beams correspond to an ultrabroadband coherent transition radiation (CTR) spectrum of 0.1 THz to 25 THz, with the single-pulse THz radiation energy of up to 50 μJ. The principle of CTR and under-compression mode of velocity bunching are introduced in this paper. And the ASTRA simulation parameters and the stability of the system are also discussed.
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Affiliation(s)
- D Wang
- Accelerator Laboratory, Department of Physics Engineering, Tsinghua University, Beijing 100084, China.
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