Trace Impurity Transport in Multi-Species Plasmas with Large Particle Fluxes

TL;DR

This paper extends classical impurity transport theory to plasmas with large, steady-state particle fluxes, revealing that trace impurities align with larger mass ions, which could benefit fusion and plasma separation techniques.

Contribution

It introduces a modified transport theory for steady-state, high-flux plasmas and demonstrates impurity alignment with larger ions through analytical and numerical methods.

Findings

Trace impurities align with larger mass ions in high-flux plasmas.

Analytical and numerical models confirm impurity behavior.

Potential applications in fusion and plasma separation.

Abstract

A burning fusion plasma has a large inwards flux of fuel and outwards flux of ash. Existing impurity transport theories do not account for a steady-state environment of such large fluxes. In this paper, we extend classical transport theory to account for a background of such fluxes. In a mainly two-ion species magnetized plasma, with oppositely directed density gradients maintained by oppositely directed sources of the two species, trace impurity ions are shown to align with the larger mass ions. This unexpected behavior is derived analytically and simulated numerically using the MITNS (Multiple-Ion Transport Numerical Solver) code. The result suggests a potential advantage of edge-fueled p-B11 fusion in extracting high-Z impurities, and possible applications in plasma-based separation methods.