Resonant Excitation of Plasma Wakefields

Muggli, P.; Allen, Brian; Yakimenko, V.; Fedurin, M.; Kusche, K.; Babzien, M.; Gold, Steven H.; Nusinovich, Gregory S.

doi:10.1063/1.3520372

Cited by 5 publications

(2 citation statements)

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“…Given the fixed dispersion, the mask sets the energy modulation period and ultimately the final current modulation, which can be controlled via the incoming chirp and ξ + function of the beamline. It was demonstrated that the technique enables some control over the final temporal period downstream of the dogleg beamline: for ∼ 10 pC modulations with sub-mm periods were produced, consistent with the resonant excitation of wakefield in plasmas (Muggli et al, 2010a). Likewise, this method was extended to produce bunches with triangular beam distribution at the ATF (Shchegolkov et al, 2015) for wakefield excitation in dielectric-lined waveguides (Antipov et al, 2012).…”

Section: Local Coupling Combined With Transverse Maskingmentioning

confidence: 81%

Bunch Shaping in Electron Linear Accelerators

Ha,

Kim,

Piot

et al. 2021

Preprint

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Modern electron linear accelerators are often designed to produce smooth bunch distributions characterized by their macroscopic ensemble-average moments. However, an increasing number of accelerator applications call for finer control over the beam distribution, e.g., by requiring specific shapes for its projection along one coordinate. Ultimately, the control of the beam distribution at the single-particle level could enable new opportunities in accelerator science. This review discusses the recent progress toward controlling electron beam distributions on the "mesoscopic" scale with an emphasis on shaping the beam or introducing complex correlations required for some applications. This review emphasizes experimental and theoretical developments of electron-bunch shaping methods based on bounded external electromagnetic fields or via interactions with the self-generated velocity and radiation fields. 1. Space-charge field with a single bunch 41 2. Space-charge field with a few bunches 43 3. Space-charge field with multiple bunches: space-charge oscillation 44 4. Space-charge field with multiple bunches: longitudinal cascade amplifier 46 5. Space-charge field with multiple bunches: plasma cascade amplifier 47 B. Shaping profiles using coherent synchrotron radiation 47 C. Shaping profiles using wakefields 49 1. Bunch compression 50 2. Bunch train generation 50 3. Single-bunch profile shaping 51 4. Control over the energy distribution 52 5. Control over longitudinal phase space 53 VI. Coupling between degrees of freedom for phase-space tailoring 54 A. Introduction 54 B. Coupling between the two transverse degrees of freedom 54 1. Producing beams with canonical angular momentum 54 2. Decoupling of CAM-dominated beams and transverse emittance partitioning 55 3. Phase-space exchange between the two transverse planes 57 C. Transverse-to-longitudinal phase-space exchangers 59 1. Emittance exchange 59 2. Current profile shaping 60 3. Bunch compression 62 4. Double phase-space exchangers 62 D. Generalized phase-space repartitioning between the three degrees of freedom 65 1. Flat beam transformation combined with emittance exchange 65 2. Coupling between the longitudinal and transverse phase spaces 65

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Section: Local Coupling Combined With Transverse Maskingmentioning

confidence: 81%

Bunch Shaping in Electron Linear Accelerators

Ha,

Kim,

Piot

et al. 2021

Preprint

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“…A single SMI mode can also be excited by a direct density modulation or microbunching of the beam either with a mask [61] or with an inverse free electron laser (IFEL) [62]. A common figure of merit for this microbunching is the bunching factor, which is defined as 𝐵 = exp(𝑖𝜃 𝑛 )/𝑁 𝑏 , where 𝜃 𝑛 are the longitudinal phases of each particle in the beam at the frequency of the desired accelerating wakefield mode, and 𝑁 𝑏 is the number of particles in the beam [63].…”

Section: Drive Beam Instabilities In Plasma-based Acceleratorsmentioning

confidence: 99%

Limiting effects in drive bunch beam dynamics in beam-driven accelerators: instability and collective effects

Simakov¹,

Andonian²,

Baturin³

et al. 2022

J. Inst.

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In a collinear beam-driven wakefield accelerator, a bunch of charged particles is accelerated by a strong electric field that is generated in a medium by a preceding high-charge drive bunch. Multiple beam-driven acceleration concepts have been proposed and demonstrated in proof-of-principle experiments. In some concepts, the medium is plasma where very strong electric fields are created due to the motion of ions and electrons with respect to each other. In other configurations, the medium is a slow-wave electromagnetic structure made of dielectric and/or metal, and high gradients are achieved due to the very short duration of the electromagnetic pulse excited in the structure by the drive bunch. Because of the high charge, and consequently long length of the drive bunch, wakefields excited by the leading particles of the drive bunch affect the trailing particles in the same bunch and result in beam-driven instabilities obstructing the drive bunch's stable propagation and extended interactions with the witness bunch, ultimately terminating the energy transfer process. This paper presents an overview of the drive-bunch beam dynamics in beam-driven structure- and plasma-based accelerators with a focus on beam instabilities that limit stable propagation of the drive bunch, such as the beam break-up instability and transverse defocusing and deflection in cases of cylindrical and planar structures and plasma waveguides. Possible mitigation techniques are discussed.

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