Search arXivSearch

arXiv · 2206.10141

Theoretical and Experimental Studies on Steady-state Microbunching

Abstract

Particle accelerators as photon sources are advanced tools in studying the structure and dynamical properties of matter. The present workhorses of these sources are storage ring-based synchrotron radiation facilities and linear accelerator-based free-electron lasers, delivering light with high repetition rate and high peak brilliance (power), respectively. The steady-state microbunching (SSMB) mechanism was proposed to bridge the gap of these two kinds of sources to generate high-average-power, high-repetition-rate coherent radiation in an electron storage ring. Such a novel light source promises new possibilities for accelerator photon science and industry applications, for example in ultra-high-energy-resolution angle-resolved photoemission spectroscopy and extreme ultraviolet lithography. The six orders of magnitude extrapolation of the electron bunch length in an SSMB storage ring compared to that of a conventional ring provides tremendous opportunities for accelerator physics research. This dissertation is devoted to the theoretical and experimental investigations of SSMB, with important results achieved. The work presented can be summarized as: first, how to realize SSMB; second, what radiation characteristics can we obtain from the formed SSMB; and third, experimentally demonstrate the working mechanism of SSMB in a real machine.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Xiujie Deng. 2022-06-21. Theoretical and Experimental Studies on Steady-state Microbunching. https://doi.org/10.1007/978-981-99-5800-9

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Stable 50 MeV Beams from a 100 Hz Laser-Wakefield Accelerator Driven by an OPCPA Laser

We demonstrate a laser-wakefield accelerator driven by a high-repetition-rate optical parametric chirped-pulse amplification (OPCPA) laser, producing stable, quasi-monoenergetic electron beams at 100 Hz. Using 70 mJ, 8.1 fs laser pulses, we obtain 47 MeV electron beams with 15 pC charge and an intrinsic energy spread below 10%. Measurements over 10,000 consecutive shots show rms fluctuations of only 1.4% in peak energy and 12% in charge, together with low pointing jitter. Principal-component analysis reveals that the beam fluctuations are described by five physically interpretable modes, dominated by slow variations below 1 Hz. Particle-in-cell simulations reproduce the measured spectrum and show that nonlinear self-focusing localizes ionization injection, resulting in the observed narrow energy distribution. The demonstrated combination of electron energy, charge, beam quality, and stability represents a significant step toward high-average-power laser-plasma accelerators.

physics.acc-ph

Thermomechanical rf breakdown from magnetically focused field emission in high-gradient normal-conducting cavities

Normal-conducting radiofrequency (rf) cavities for muon-collider ionization cooling must operate at high accelerating gradients in strong solenoidal magnetic fields, where rf breakdown can be enhanced by the magnetic focusing of field-emitted electrons. In this work, field-emitted electrons were tracked in the realistic field maps of rectilinear cooling-lattice cavities to test the validity of the previously developed localized-bombardment picture with simplified field maps. Under comparable reduced-field assumptions, the tracking results show good agreement with previous results. The full rf eigenmode fields and nonuniform solenoidal fields modify the idealized beamlet structure, producing rf phase dependent centroid shifts and broadened impact distributions from solenoid fringe fields. Nevertheless, the original model remains a useful framework for estimating limits on operating gradients. The thermal response is evaluated analytically using this model, with material properties varied to assess the coupled effects of heat transport and thermomechanical damage threshold. These results can inform cavity testing in strong solenoidal fields, muon ionization cooling channel designs, and other applications requiring high-gradient rf operation in magnetic fields.

physics.acc-ph

High-power attosecond X-ray free-electron lasers: physics and design strategy

Attosecond pulses from X-ray free-electron laser (XFEL) have opened new opportunities for probing ultrafast electronic dynamics on the Angstrom--attosecond spatiotemporal scale. Most attosecond XFEL concepts rely on generating an ultrashort high-current spike through either external laser modulation or accelerator-based beam manipulation. Despite their different implementations, these approaches share the same essential physics, namely that the XFEL amplification is confined to a short effective lasing window within the electron beam. However, existing studies are often scheme-specific and do not yet provide a unified quantitative picture of how fundamental electron-beam properties constrain high-power attosecond performance. In this work, we investigate the general physics and scheme-independent requirements for generating high-power attosecond X-ray pulses from a short current spike. From the perspective of post-saturation superradiant evolution, we show that the effective lasing length of the electron beam governs both the attainable peak power and the pulse duration. We further examine the distinct roles of slice energy spread, slice emittance, energy chirp, undulator tapering, and transverse beam tilt. Our results reveal the trade-off between peak power, pulse shortening, and single-spike probability, and provide facility-independent guidelines for optimizing electron-beam phase-space manipulation toward terawatt-class attosecond XFEL operation.

physics.acc-ph