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van de Wetering JJ, Hooker SM, Walczak R. Multi-GeV wakefield acceleration in a plasma-modulated plasma accelerator. Phys Rev E 2024; 109:025206. [PMID: 38491682 DOI: 10.1103/physreve.109.025206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/11/2024] [Indexed: 03/18/2024]
Abstract
We investigate the accelerator stage of a plasma-modulated plasma accelerator (P-MoPA) [Jakobsson et al., Phys. Rev. Lett. 127, 184801 (2021)0031-900710.1103/PhysRevLett.127.184801] using both the paraxial wave equation and particle-in-cell (PIC) simulations. We show that adjusting the laser and plasma parameters of the modulator stage of a P-MoPA allows the temporal profile of pulses within the pulse train to be controlled, which in turn allows the wake amplitude in the accelerator stage to be as much as 72% larger than that generated by a plasma beat-wave accelerator with the same total drive laser energy. Our analysis shows that Rosenbluth-Liu detuning is unimportant in a P-MoPA if the number of pulses in the train is less than ∼30, and that this detuning is also partially counteracted by increased red-shifting, and hence increased pulse spacing, towards the back of the train. An analysis of transverse mode oscillations of the driving pulse train is found to be in good agreement with 2D (Cartesian) PIC simulations. PIC simulations demonstrating energy gains of ∼1.5GeV (∼2.5GeV) for drive pulse energies of 2.4J (5.0J) are presented. Our results suggest that P-MoPAs driven by few-joule, picosecond pulses, such as those provided by high-repetition-rate thin-disk lasers, could accelerate electron bunches to multi-GeV energies at pulse repetition rates in the kilohertz range.
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Affiliation(s)
- J J van de Wetering
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - S M Hooker
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - R Walczak
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
- Somerville College, Woodstock Road, Oxford OX2 6HD, United Kingdom
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Marasciulli A, Labate L, Tomassini P, Gizzi LA. Signatures of resonantly driven laser-wakefield excitation by a pulse train generated by an optical delay mask. APPLIED OPTICS 2023; 62:9368-9374. [PMID: 38108709 DOI: 10.1364/ao.506107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/12/2023] [Indexed: 12/19/2023]
Abstract
Electron plasma waves can be efficiently excited by a resonant train of ultrashort pulses, spatially separated by a plasma wavelength. Generating a pulse train from a single amplified ultrashort pulse may be challenging when dealing with large beams. Here we discuss a pulse splitting technique using a simple delay mask that can be adapted to large diameter petawatt beams. We show via detailed numerical simulations that unique signatures of electrons accelerated by a resonantly excited wakefield can be obtained from realistic focused double-pulse trains obtained from a single-region delay mask.
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Jonnerby J, von Boetticher A, Holloway J, Corner L, Picksley A, Ross AJ, Shalloo RJ, Thornton C, Bourgeois N, Walczak R, Hooker SM. Measurement of the decay of laser-driven linear plasma wakefields. Phys Rev E 2023; 108:055211. [PMID: 38115527 DOI: 10.1103/physreve.108.055211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 10/10/2023] [Indexed: 12/21/2023]
Abstract
We present measurements of the temporal decay rate of one-dimensional (1D), linear Langmuir waves excited by an ultrashort laser pulse. Langmuir waves with relative amplitudes of approximately 6% were driven by 1.7J, 50fs laser pulses in hydrogen and deuterium plasmas of density n_{e0}=8.4×10^{17}cm^{-3}. The wakefield lifetimes were measured to be τ_{wf}^{H_{2}}=(9±2) ps and τ_{wf}^{D_{2}}=(16±8) ps, respectively, for hydrogen and deuterium. The experimental results were found to be in good agreement with 2D particle-in-cell simulations. In addition to being of fundamental interest, these results are particularly relevant to the development of laser wakefield accelerators and wakefield acceleration schemes using multiple pulses, such as multipulse laser wakefield accelerators.
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Affiliation(s)
- J Jonnerby
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - A von Boetticher
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - J Holloway
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - L Corner
- Cockcroft Institute of Accelerator Science, University of Liverpool, Liverpool WA4 4AD, United Kingdom
| | - A Picksley
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - A J Ross
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - R J Shalloo
- John Adams Institute for Accelerator Science, Imperial College London, London SW7 2AZ, United Kingdom
| | - C Thornton
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - N Bourgeois
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - R Walczak
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - S M Hooker
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
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van de Wetering JJ, Hooker SM, Walczak R. Stability of the modulator in a plasma-modulated plasma accelerator. Phys Rev E 2023; 108:015204. [PMID: 37583169 DOI: 10.1103/physreve.108.015204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/19/2023] [Indexed: 08/17/2023]
Abstract
We explore the regime of operation of the modulator stage of a recently proposed laser-plasma accelerator scheme [Phys. Rev. Lett. 127, 184801 (2021)0031-900710.1103/PhysRevLett.127.184801], dubbed the plasma-modulated plasma accelerator (P-MoPA). The P-MoPA scheme offers a potential route to high-repetition-rate, GeV-scale plasma accelerators driven by picosecond-duration laser pulses from, for example, kilohertz thin-disk lasers. The first stage of the P-MoPA scheme is a plasma modulator in which a long, high-energy "drive" pulse is spectrally modulated by copropagating in a plasma channel with the low-amplitude plasma wave driven by a short, low-energy "seed" pulse. The spectrally modulated drive pulse is converted to a train of short pulses, by introducing dispersion, which can resonantly drive a large wakefield in a subsequent accelerator stage with the same on-axis plasma density as the modulator. In this paper we derive the 3D analytic theory for the evolution of the drive pulse in the plasma modulator and show that the spectral modulation is independent of transverse coordinate, which is ideal for compression into a pulse train. We then identify a transverse mode instability (TMI), similar to the TMI observed in optical fiber lasers, which sets limits on the energy of the drive pulse for a given set of laser-plasma parameters. We compare this analytic theory with particle-in-cell (PIC) simulations and find that even higher energy drive pulses can be modulated than those demonstrated in the original proposal.
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Affiliation(s)
- J J van de Wetering
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - S M Hooker
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - R Walczak
- John Adams Institute for Accelerator Science and Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
- Somerville College, Woodstock Road, Oxford OX2 6HD, United Kingdom
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von Boetticher A, Walczak R, Hooker SM. Modulational instability in large-amplitude linear laser wakefields. Phys Rev E 2023; 107:L023201. [PMID: 36932619 DOI: 10.1103/physreve.107.l023201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 11/15/2022] [Indexed: 06/18/2023]
Abstract
We investigate the growth of ion density perturbations in large-amplitude linear laser wakefields via two-dimensional particle-in-cell simulations. Growth rates and wave numbers are found to be consistent with a longitudinal strong-field modulational instability. We examine the transverse dependence of the instability for a Gaussian wakefield envelope and show that growth rates and wave numbers can be maximized off axis. On-axis growth rates are found to decrease with increasing ion mass or electron temperature. These results are in close agreement with the dispersion relation of a Langmuir wave with an energy density that is large compared to the plasma thermal energy density. The implications for wakefield accelerators, in particular multipulse schemes, are discussed.
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Affiliation(s)
- A von Boetticher
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Rudolf Peierls Centre for Theoretical Physics, Parks Road, Oxford OX1 3PU, United Kingdom
| | - R Walczak
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Somerville College, Woodstock Road, Oxford OX2 6HD, United Kingdom
| | - S M Hooker
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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