Ponderomotive laser force under extreme focusing and control of transverse phase space

Thursday 19 Jun 2025, 11:00 → 12:05 Europe/Zurich

6/2-024 - BE Auditorium Meyrin (CERN)

11:00 → 11:05 Introduction

Speaker: Richard Scrivens (CERN)

11:05 → 12:05 Advanced Light Source Upgrade Project

Abstract:
When charged particles interact with laser fields, they are usually thought to be pushed out from the regions of higher laser intensity via the mechanism known as the ponderomotive force (PMF). In contrast to the existing theories, we show that there exist several regimes in which charged particles are drawn into the regions of strongly focused laser fields. We derive a simple, covariant, and relativistically correct expression for the ponderomotive laser force that holds for arbitrary strength of field focusing and for all particle velocities. We predict three new, to the best of our knowledge, physical effects: (1) focusing-dependent reversal of PMF, (2) non-relativistic reversal of PMF, and (3) non-reciprocity of PMF for weakly relativistic particle velocities.
Furthermore, we show that space-charge driven deformation of the transverse phase space of a charged particle beam can be corrected by radially polarized laser beams.
For the parameters of an electron UED instrument, we demonstrate in simulations that the ''nonlinear'' emittance of an electron beam can be reduced by an order of magnitude.

Speaker: Vitaliy Goryashko