arXiv subjects

Michele Bergamaschi

Publications and source records attributed to Michele Bergamaschi.

3 recordsLinked to original sources

arXiv2026

Eigenvalue bounds for preconditioned symmetric multiple saddle-point matrices with block-triangular preconditioners

We develop eigenvalue bounds for symmetric, block-tridiagonal multiple saddle-point linear systems, preconditioned with block-triangular matrices, based on approximate Schur complements. Irrespective on the number of blocks, we prove that all complex eigenvalues, with nontrivial imaginary part, are strictly contained in a circle within the complex plane, with center 1. The real and positive eigenvalues are bounded in terms of the extremal roots of a sequences of parametric polynomials. Numerical results reveal that the bounds describe very well the eigenvalue distribution of the preconditioned matrix.

math.NA↗

arXiv2024

Implementation of Light Diagnostics for Wakefields at AWAKE

We describe the implementation of light diagnostics for studying the self-modulation instability of a long relativistic proton bunch in a 10m-long plasma. The wakefields driven by the proton bunch dissipate their energy in the surrounding plasma. The amount of light emitted as atomic line radiation is related to the amount of energy dissipated in the plasma. We describe the setup and calibration of the light diagnostics, configured for a discharge plasma source and a vapor plasma source. For both sources, we analyze measurements of the light from the plasma only (no proton bunch). We show that with the vapor plasma source, the light signal is proportional to the energy deposited in the vapor/plasma by the ionizing laser pulse. We use this dependency to obtain the parameters of an imposed plasma density step. This dependency also forms the basis for ongoing studies, focused on investigating the wakefield evolution along the plasma.

physics.plasm-ph↗

arXiv2022

The AWAKE Run 2 programme and beyond

Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. Use of high energy protons to drive wakefields in plasma has been demonstrated during Run 1 of the AWAKE programme at CERN. Protons of energy 400 GeV drove wakefields that accelerated electrons to 2 GeV in under 10 m of plasma. The AWAKE collaboration is now embarking on Run 2 with the main aims to demonstrate stable accelerating gradients of 0.5-1 GV/m, preserve emittance of the electron bunches during acceleration and develop plasma sources scalable to 100s of metres and beyond. By the end of Run 2, the AWAKE scheme should be able to provide electron beams for particle physics experiments and several possible experiments have already been evaluated. This article summarises the programme of AWAKE Run 2 and how it will be achieved as well as the possible application of the AWAKE scheme to novel particle physics experiments.

physics.acc-ph↗