Relaxation to non-equilibrium in expanding ultracold neutral plasmas

Abstract

We investigate the strongly correlated ion dynamics and the degree of coupling achievable in the evolution of freely expanding ultracold neutral plasmas. We demonstrate that the ionic Coulomb coupling parameter ${\Gamma }_{\mathrm{i}}$ increases considerably in later stages of the expansion, reaching the strongly coupled regime despite the well-known initial drop of ${\Gamma }_{\mathrm{i}}$ to order unity due to disorder-induced heating. Furthermore, we formulate a suitable measure of correlation and show th at ${\Gamma }_{\mathrm{i}}$ calculated from the ionic temperature and density reflects the degree of order in the system if it is sufficiently close to a quasisteady state. At later times, however, the expansion of the plasma cloud becomes faster than the relaxation of correlations, and the system does not reach thermodynamic equilibrium anymore.

References in corpus (9)

• Creation of an Ultracold Neutral Plasma
• Plasma Oscillations and Expansion of an Ultracold Neutral Plasma
• Using Absorption Imaging to Study Ion Dynamics in an Ultracold Neutral Plasma
• Coulomb crystallization in expanding laser-cooled neutral plasmas
• Kinetic modelling and molecular dynamics simulation of ultracold neutral plasmas including ionic correlations
• Evolution of Ultracold, Neutral Plasmas
• Electron Temperature of Ultracold Plasmas
• Influence of electron-ion collisions on Coulomb crystallization of ultracold neutral plasmas
• Formation of correlations in strongly coupled plasmas

Cited by in corpus (20)

• Ultracold Neutral Plasmas
• Fluorescence measurements of expanding strongly-coupled neutral plasmas
• Velocity Relaxation in a Strongly Coupled Plasma
• Strongly Coupled Plasmas via Rydberg-Blockade of Cold Atoms
• Rydberg atom formation in strongly correlated ultracold plasmas
• Ion Temperature Evolution in an Ultracold Neutral Plasma
• Fundamental Photoemission Brightness Limit from Disorder Induced Heating
• Recombination fluorescence in ultracold neutral plasmas
• Ultracold neutral plasma expansion in two dimensions
• Strong Coulomb Coupling Influences Ion and Neutral Temperatures in Atmospheric Pressure Plasmas
• Tracing non-equilibrium plasma dynamics on the attosecond timescale in small clusters
• Expansion Dynamics of Cold Non-Neutral Plasma
• High Resolution Ionization of Ultracold Neutral Plasmas
• Ion friction at small values of the Coulomb logarithm
• Influence of Electron Evaporative Cooling on Ultracold Plasma Expansion
• Measurement and simulation of laser-induced fluorescence from non-equilibrium ultracold neutral plasmas
• Creating Non-Maxwellian Velocity Distributions in Ultracold Plasmas
• Expansion of Ultracold Neutral Plasmas with Exponentially Decaying Density Distributions
• Electron Temperature Relaxation in the Clusterized Ultracold Plasmas
• Complex non-equilibrium dynamics in plasmas