arXiv subjects

A. Sloss

Publications and source records attributed to A. Sloss.

4 recordsLinked to original sources

arXiv2025

Excitation of Giant Surface Waves During Laser Wake Field Acceleration

We have detected the presence of very high intensity surface waves that are excited during plasma waveguided laser wakefield acceleration. Wakefield acceleration can be enchanced by the introduction of an ``all optical" plasma waveguide that confines and guides a laser pulse at the optimal intensity over long distances, producing quasimonoenergetic multi-GeV electron bunches. However strong pulses of radio frequency radiation (RF) are also produced, and particle in cell simulations show why: a continuous stream of multi-MeV electrons are also ejected radially from the plasma due to nonlinear wave breaking, and these excite and copropagate coherently with a giant cylindrical Sommerfeld surface wave. Laboratory measurements, simulations, and analytic approximations all converge on a 20 J laser pulse exciting a 1 Joule, 400 GW broadband THz surface wave, with a peak electric field strength of 35 GV/m.

physics.plasm-ph↗

arXiv2025

Longitudinal shaping of plasma waveguides using diffractive axicons for laser wakefield acceleration

New techniques for the optical generation of plasma waveguides -- optical fibres for ultra-intense light pulses -- have become vital to the advancement of multi-GeV laser wakefield acceleration. Here, we demonstrate the fabrication and characterization of a transmissive eight-level logarithmic diffractive axicon (LDA) for the generation of meter-scale plasma waveguides. These LDAs enable the formation of a Bessel-like beam with controllable start and end locations of the focal line and near-constant intensity on axis. We present measurements of the Bessel-like focal profile produced by the LDA, and of the leading end of the plasma column generated by it. One important feature is the formation of a funnel-mouthed plasma channel entrance that can act as waveguide coupler. We also compare the diffraction efficiency of our 8-level LDA to 4-level and binary versions, with measurements comparing well to theory.

physics.plasm-ph↗

arXiv2024

Meter-scale supersonic gas jets for multi-GeV laser-plasma accelerators

Pushing the high energy frontier of laser wakefield electron acceleration (LWFA) to 10 GeV and beyond requires extending the propagation of relativistic intensity pulses to ~1 m in a low density ($N_e\sim 10^{17} cm^{-3}$) plasma waveguide. We present the development and characterization of two types of supersonic gas jet for meter-scale multi-GeV laser wakefield accelerators. The first type is a 30-cm long single-module gas jet, which demonstrates good axial uniformity using hydrogen, the preferred working gas for LWFA. The second type is a modular jet composed of multiple 11-cm-long modules. Longitudinal density profile control is demonstrated with a 2-module (22 cm long) hydrogen jet using gas valve trigger timing. A 1.0-m-long jet is then assembled from 9 modules, and generation of 1.0-m long hydrogen plasma is demonstrated using a femtosecond Bessel beam. To our knowledge, this is the longest gas jet laser plasma yet generated.

physics.acc-ph↗

arXiv2022

Snowmass 2021 Scintillating Bubble Chambers: Liquid-noble Bubble Chambers for Dark Matter and CE$\nu$NS Detection

The Scintillating Bubble Chamber (SBC) Collaboration is developing liquid-noble bubble chambers for the quasi-background-free detection of low-mass (GeV-scale) dark matter and coherent scattering of low-energy (MeV-scale) neutrinos (CE$\nu$NS). The first physics-scale demonstrator of this technique, a 10-kg liquid argon bubble chamber dubbed SBC-LAr10, is now being commissioned at Fermilab. This device will calibrate the background discrimination power and sensitivity of superheated argon to nuclear recoils at energies down to 100 eV. A second functionally-identical detector with a focus on radiopure construction is being built for SBC's first dark matter search at SNOLAB. The projected spin-independent sensitivity of this search is approximately $10^{-43}$ cm$^2$ at 1 GeV$/c^2$ dark matter particle mass. The scalability and background discrimination power of the liquid-noble bubble chamber make this technique a compelling candidate for future dark matter searches to the solar neutrino fog at 1 GeV$/c^2$ particle mass (requiring a $\sim$ton-year exposure with non-neutrino backgrounds sub-dominant to the solar CE$\nu$NS signal) and for high-statistics CE$\nu$NS studies at nuclear reactors.

physics.ins-det↗