Spatio-temporal dynamics of relativistic electron bunches during the micro-bunching instability in storage rings

Évain, C.; Barros, Joanna; Loulergue, Alexandre; Tordeux, Marie-Agnès; Nagaoka, R.; Labat, M.; Cassinari, L.; Creff, Gaëlle; Manceron, L.; Brubach, Jean‐Blaise; Roy, Pascale Le; Couprie, Marie-Emmanuelle

doi:10.1209/0295-5075/98/40006

Cited by 32 publications

(35 citation statements)

References 23 publications

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“…Because these microstructures produce strong THz radiation bursts with an intensity more than 5 orders of magnitude higher than incoherent synchrotron radiation [2] potentially leading to e.g. applications in non-linear spectroscopy, this process is subject to intense investigations [3][4][5][6][7][8][9][10][11][12]. Although far-field CSR measurements are a useful approach, additional methods exploring the phase space more directly are desirable in order to tighter connect * stefan.funkner@kit.edu † Present address:PSI, Villigen, Switzerland ‡ Present address:DESY, Hamburg, Germany theory and experiment.…”

Section: Introductionmentioning

confidence: 99%

High throughput data streaming of individual longitudinal electron bunch profiles

Funkner

Blomley

Bründermann

et al. 2019

Phys. Rev. Accel. Beams

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The development of fast detection methods for comprehensive monitoring of electron bunches is a prerequisite to gain comprehensive control over the synchrontron emission in storage rings with their MHz repetition rate. Here, we present a proof-of-principle experiment with at detailed description of our implementation to detect the longitudinal electron bunch profiles via single-shot, near-field electro-optical sampling at the Karlsruhe Research Accelerator (KARA). Our experiment is equipped with an ultra-fast line array camera providing a high-throughput MHz data stream. We characterize statistical properties of the obtained data set and give a detailed description for the data processing as well as for the calculation of the charge density profiles, which where measured in the short-bunch operation mode of KARA. Finally, we discuss properties of the bunch profile dynamics on a coarse-grained level on the example of the well-known synchrotron oscillation. arXiv:1809.07530v1 [physics.acc-ph]

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Section: Introductionmentioning

confidence: 99%

High throughput data streaming of individual longitudinal electron bunch profiles

Funkner

Blomley

Bründermann

et al. 2019

Phys. Rev. Accel. Beams

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“…During such process, the electron-beam (e-beam) quality can be degraded due to microbunching instability (MBI) caused by collective effects like longitudinal space charge [8,9] and coherent synchrotron radiation [10][11][12][13][14], which are extensively studied both in theory and in experiment [15][16][17][18][19]. This instability amplifies the e-beam energy and density modulation and increases its energy spread up to a level that can be detrimental not only to the FEL gain process [9,20], but also to the beam brightness in storage rings and linacs [21,22]. MBI can be suppressed by a laser heater (LH) [8], which was first installed at the Linac Coherent Light Source (LCLS) and has been widely used in other FEL facilities [9,15,20,23].…”

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confidence: 99%

Laguerre-Gaussian Mode Laser Heater for Microbunching Instability Suppression in Free-Electron Lasers

et al. 2020

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Microbunching instability (MBI) driven by beam collective effects is known to be detrimental to highbrightness storage rings, linacs, and free-electron lasers (FELs). One known way to suppress this instability is to induce a small amount of energy spread to an electron beam by a laser heater. The distribution of the induced energy spread greatly affects MBI suppression and can be controlled by shaping the transverse profile of the heater laser. Here, we present the first experimental demonstration of effective MBI suppression using a LG 01 transverse laser mode and compare the improved results with respect to traditional Gaussian transverse laser mode at the Linac Coherent Light Source. The effects on MBI suppression are characterized by multiple downstream measurements, including longitudinal phase space analysis and coherent radiation spectroscopy. We also discuss the role of LG 01 shaping in soft x-ray selfseeded FEL emission, one of the most advanced operation modes of a FEL for which controlled suppression of MBI is critical.

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“…This density is so high that the light emitted by the electrons affects the dynamics of neighboring electrons in a dramatic way. In particular, this nonlinear collective effect leads to spontaneous formation of small-scale structures (in the sub- * Corresponding author : serge.bielawski@univ-lille.fr millimeter to centimeter range) in the longitudinal profile of electron bunches [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. This is known as the microbunching instability [3,4,18,19] (see Figure 1) .…”

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confidence: 99%

From self-organization in relativistic electron bunches to coherent synchrotron light: observation using a photonic time-stretch digitizer

Bielawski¹,

Blomley²,

Brosi³

et al. 2019

Sci Rep

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In recent and future synchrotron radiation facilities, relativistic electron bunches with increasingly high charge density are needed for producing brilliant light at various wavelengths, from X-rays to terahertz. In such conditions, interaction of electron bunches with their own emitted electromagnetic fields leads to instabilities and spontaneous formation of complex spatial structures. Understanding these instabilities is therefore key in most electron accelerators. However, investigations suffer from the lack of non-destructive recording tools for electron bunch shapes. In storage rings, most studies thus focus on the resulting emitted radiation. Here, we present measurements of the electric field in the immediate vicinity of the electron bunch in a storage ring, over many turns. For recording the ultrafast electric field, we designed a photonic time-stretch analog-to-digital converter with terasamples/second acquisition rate. We could thus observe the predicted link between spontaneous pattern formation and giant bursts of coherent synchrotron radiation in a storage ring.

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Spatio-temporal dynamics of relativistic electron bunches during the micro-bunching instability in storage rings

Cited by 32 publications

References 23 publications

High throughput data streaming of individual longitudinal electron bunch profiles

High throughput data streaming of individual longitudinal electron bunch profiles

Laguerre-Gaussian Mode Laser Heater for Microbunching Instability Suppression in Free-Electron Lasers

From self-organization in relativistic electron bunches to coherent synchrotron light: observation using a photonic time-stretch digitizer

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