Velocity Relaxation in a Strongly Coupled Plasma

TL;DR

This paper investigates how ions in an ultracold neutral plasma relax in a strongly coupled regime, revealing deviations from traditional theories through experiments and simulations that show non-Markovian dynamics.

Contribution

It introduces an optical pump-probe method to directly measure relaxation rates in strongly coupled Coulomb systems, surpassing limitations of existing Landau-Spitzer theory.

Findings

Experimental relaxation rates differ from Landau-Spitzer predictions.

Numerical simulations show non-Markovian behavior at early times.

The method enables direct observation of strongly coupled plasma dynamics.

Abstract

Collisional relaxation of Coulomb systems is studied in the strongly coupled regime. We use an optical pump-probe approach to manipulate and monitor the dynamics of ions in an ultracold neutral plasma, which allows direct measurement of relaxation rates in a regime where common Landau-Spitzer theory breaks down. Numerical simulations confirm the experimental results and display non-Markovian dynamics at early times.