Performance Bounds of Magnetic Traps for Neutral Particles

TL;DR

This paper establishes fundamental performance limits for magnetic traps for neutral particles, compares classical designs to these bounds, and demonstrates that modern shape optimization can significantly improve trap performance.

Contribution

It introduces a framework to determine fundamental bounds on magnetic trap performance and shows that optimized designs can outperform classical traps by nearly twofold.

Findings

Classical traps are significantly below fundamental performance limits.

Topologically optimized traps nearly double the efficiency of traditional designs.

The framework can be extended to plasma confinement limitations.

Abstract

Knowledge of the fundamental limitations on a magnetic trap for neutral particles is of paramount interest to designers as it allows for the rapid assessment of the feasibility of specific trap requirements or the quality of a given design. In this paper, performance limitations are defined for convexity of magnetic trapping potential and bias field using a local approximation in the trapping center. As an example, the fundamental bounds are computed for current supporting regions in the form of a spherical shell, a cylindrical region, and a box. A Pareto-optimal set considering both objectives is found and compared with known designs of the Baseball trap and Ioffe-Pritchard trap. The comparison reveals a significant gap in the performance of classical trap designs from the fundamental limitations. This indicates a possibility of improved trap designs and modern techniques of shape synthesis are applied in order to prove their existence. The topologically optimized traps perform almost two times better as compared to conventional designs. Last, but not least, the developed framework might serve as a prototype for the formulation of fundamental limitations on plasma confinement in a wider sense.