Inverse Bremsstrahlung current drive

TL;DR

This paper analyzes how Bremsstrahlung absorption can generate plasma current, revealing that the actual current exceeds naive estimates due to recoil momentum and asymmetric power absorption.

Contribution

It demonstrates that plasma current from Bremsstrahlung absorption is higher than previously estimated, accounting for recoil momentum and asymmetric energy absorption effects.

Findings

Current exceeds naive estimates based on photon momentum alone

Recoil momentum from Coulomb interactions enhances current

Asymmetric energy absorption within electron velocity distribution contributes to current

Abstract

The generation of the plasma current resulting from Bremsstrahlung absorption is considered. It is shown that the electric current is higher than the naive estimates assuming that electrons absorb only the photon momentum and using the Spitzer conductivity would suggest. The current enhancement is in part because electrons get the recoil momentum from the Coulomb field of ions during the absorption and in part because the electromagnetic power is absorbed asymmetrically within the electron velocity distribution space.