Spiral Tuning of Wire-metamaterial Cavity for Plasma Haloscope

TL;DR

This paper introduces a spiral wire configuration for plasma haloscopes that allows continuous frequency tuning and faster scanning speeds, enhancing the search for dark matter axions.

Contribution

The novel spiral wire arrangement provides a new tuning mechanism enabling continuous frequency adjustment and improved scanning efficiency in plasma haloscopes.

Findings

Achieved 25% continuous frequency tuning with a single rotation.

Demonstrated faster scanning speeds compared to traditional methods.

Experimental results closely matched numerical simulations.

Abstract

Axions are hypothetical particles that provide a compelling solution to two major mysteries in modern physics: the strong CP problem and the nature of dark matter. The plasma haloscope has been proposed as a promising approach for probing the higher-mass regime for dark matter axions by employing a periodic arrangement of conducting wires. In this work, we introduce a novel tuning mechanism for such wire-based structures by arranging the wires into a spiral configuration. This design enables continuous frequency tuning of 25% with a single central rotation while maintaining the form factor. It also achieves scanning speeds several times faster than traditional tuning approaches, primarily due to the circular perimeter geometry, making it well suited for solenoidal magnet bores. To validate the concept, we fabricated a prototype cavity with six spiral arms and experimentally demonstrated its feasibility, obtaining frequency tuning in close agreement with numerical simulations.