Impact of Electron Transport Models on Capillary Discharge Plasmas

TL;DR

This study evaluates how different electron transport models affect the accuracy of magnetohydrodynamic simulations of capillary discharge waveguides, revealing significant discrepancies in predicted electron temperatures and magnetic fields.

Contribution

It provides a comparative analysis of three electron transport models in MHD simulations, highlighting their impact on plasma parameter predictions in accelerator design.

Findings

The Epperlein-Haines model overestimates electron temperature by over 20%.

The Spitzer model predicts higher electron temperatures than other models.

Different models significantly influence magnetic field predictions.

Abstract

Magnetohydrodynamics (MHD) can be used to model capillary discharge waveguides in laser-wakefield accelerators. However, the predictive capability of MHD can suffer due to poor microscopic closure models. Here, we study the impact of electron heating and thermal conduction on capillary waveguide performance as part of an effort to understand and quantify uncertainties in modeling and designing next-generation plasma accelerators. To do so, we perform two-dimensional high-resolution MHD simulations using an argon-filled capillary discharge waveguide with three different electron transport coefficients models. The models tested include (i) Davies et al. (ii) Spitzer, and (iii) Epperlein-Haines (EH). We found that the EH model overestimates the electron temperature inside the channel by over $20\%$ while predicting a lower azimuthal magnetic field. Moreover, the Spitzer model, often used in MHD simulations for plasma-based accelerators, predicts a significantly higher electron temperature than the other models suggest.