Reconstructing nonlinear plasma wakefields using a generalized temporally encoded spectral shifting analysis

TL;DR

This paper extends spectral interferometry analysis to accurately reconstruct nonlinear plasma wakefields with dissimilar probe pulses, improving measurement precision for plasma diagnostics.

Contribution

The authors generalize TESS analysis for arbitrary spectral profiles and nonlinear regimes, addressing previous Gaussian approximation limitations.

Findings

Gaussian approximation causes up to twofold error in wakefield amplitude estimation

Extended TESS method enables more accurate measurement of nonlinear wakefields

Potential for rapid, on-shot plasma wakefield diagnostics at low densities

Abstract

We generalize the temporally encoded spectral shifting (TESS) analysis for measuring plasma wakefields using spectral interferometry to dissimilar probe pulses of arbitrary spectral profile and to measuring nonlinear wakefields. We demonstrate that the Gaussian approximation used up until now results in a substantial miscalculation of the wakefield amplitude, by a factor of up to two. A method to accurately measure higher amplitude quasilinear and nonlinear wakefields is suggested, using an extension to the TESS procedure, and we place some limits on its accuracy in these regimes. These extensions and improvements to the analysis demonstrate its potential for rapid and accurate on-shot diagnosis of plasma wakefields, even at low plasma densities.