Bremsstrahlung constraints on proton-Boron 11 inertial fusion

TL;DR

This paper investigates the challenges of achieving breakeven in proton-Boron 11 inertial fusion by analyzing bremsstrahlung radiation trapping, requiring significantly higher plasma density and pressure than current capabilities.

Contribution

It introduces burn simulations that incorporate bremsstrahlung emission and reabsorption to determine conditions for breakeven in pB11 ICF.

Findings

Breakeven requires stagnation areal density about 100 times higher than current.

Achieving breakeven demands pressures 1000 times greater than present.

Effective radiation trapping is essential for net energy gain.

Abstract

Proton-Boron 11 (pB11) fusion is relatively safe and clean, but difficult to use for net power production, since bremsstrahlung radiation tends to radiate away power more quickly than it can be generated by fusion power, particularly once poisoning by alpha particles is taken into account. While in magnetic confinement fusion (MCF), this problem can be addressed by deconfining the alphas, in inertial confinement fusion (ICF) the alphas that heat the plasma linger for the duration of the reaction. Thus, it becomes essential to trap the bremsstrahlung radiation in the hotspot. Through burn simulations incorporating bremsstrahlung emission and reabsorption, we infer the necessary conditions to capture enough radiation to produce scientific breakeven in a pB11 ICF plasma. We find that breakeven requires a stagnation areal density roughly two orders of magnitude higher than the current state-of-the-art, at pressures three orders of magnitude higher.