相关论文: Halo Coupling and Cleaning by a Space Charge Reson…

An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The…

Beam halo formation poses a critical challenge for high-repetition-rate continuous-wave (CW) free-electron lasers (FELs), directly affecting beam quality and machine protection, as observed during the LCLS-II commissioning. We identify and…

High intensity proton linacs and storage rings are central for the development of advanced neutron sources, extending the intensity frontier in high energy physics, as drivers for the production of pions in neutrino factories or muon…

Linear halo bias is the response of dark matter halo number density to a long wavelength fluctuation in the dark matter density. Using abundance matching between separate universe simulations which absorb the latter into a change in the…

We explore the potential impact of colored noise on space-charge-induced halo formation. By coupling particle orbits to parametric resonance, colored noise due to space-charge fluctuations and/or imperfections in the beamline can eject…

We present the results of numerical simulations and experimental studies about the effects of resonant and random excitations on proton losses, emittances, and beam distributions in the Large Hadron Collider (LHC). In addition to shedding…

At strong space charge, transverse modes of the bunch core may effectively couple with those of the halo, leading to instabilities well below the core-only transverse mode-coupling threshold.

In particle accelerators, particle losses to surrounding components must be minimized. These particles usually have been driven into an undesired "halo" outside the desired distribution before being lost. The processes involved and physical…

Recently, the first direct measurement of a full 6D accelerator beam distribution was reported [1]. That work observed a correlation between energy and transverse coordinates, for which the energy distribution becomes hollowed and…

Radio-loud active galactic nuclei, in particular radio-loud quasars, are fueled by accretion onto supermassive black holes and are among the most energetic sources in the Universe. While their impact on their surroundings - from the…

Next-generation particle accelerators demand advanced beam-diagnostic capabilities to ensure high performance, operational reliability, and sustainable machine operation. Increasing beam intensities and stored energies make the precise…

We present a halo-model-based approach to calculate the cross-correlation between $\rm{21\,cm}$ HI intensity fluctuations and $\rm{Ly}\alpha$ emitters (LAE) during the epoch of reionization (EoR). Ionizing radiation around dark matter halos…

Controlling non-linear effects in the transverse dynamics of charged particle beams in circular accelerators opens new possibilities for controlling some of the beam properties. Beam splitting by crossing a stable 1D non-linear resonance is…

For high-intensity linear accelerators, space-charge halo mechanisms are largely classified into two families: particle resonances and parametric instabilities. The dominance between the fourth-order particle resonance and the envelope…

Due to the potentially adverse effects of the generation of halo particles in intense proton beams, it is imperative to have a clear understanding of the mechanisms that can lead to halo formation for current and proposed high- intensity…

It has been empirically observed in both experiments and particle-in-cell simulations that space-charge-dominated beams suffer strong growth in statistical phase-space area (degraded quality) and particle losses in alternating gradient…

Three alternative designs of the European Spallation Source (ESS) high energy linac are described. The most promising ones are either a normalconducting (nc) coupled cavity linac (CCL) up tofinal energy or a change at 407 MeV to only one…

Halos of similar mass and redshift exhibit a large degree of variability in their differential properties, such as dark matter, hot gas, and stellar mass density profiles. This variability is an indicator of diversity in the formation…

Halo dynamics influences global accelerator performance: beam lifetimes, emittance growth, dynamic aperture, and collimation efficiency. Halo monitoring and control are also critical for the operation of high-power machines. For instance,…

One of the main concerns in the design of low emittance linear accelerators (linacs) is the preservation of beam emittance. Here we discuss one possible source of emittance dilution, the coupler kick, due to transverse electromagnetic…