Speaker
Description
The search for post-inflation axion dark matter has pushed towards axion masses corresponding to frequencies above 10 GHz (40 µeV). As traditional haloscopes are limited by the loss of interaction volume at high frequencies, this has required the development of new techniques. A plasma haloscope employs wire metamaterials where the inter-wire spacing controls the resonant frequency.
The Axion Longitudinal Plasma Haloscope (ALPHA) collaboration aims to use this concept to search the post-inflation axion starting in 2028. Pending the delivery of the magnet, these plasma haloscopes will be used to search for dark photons in 2026. However, tuning these resonators often requires multiple rotational axes making them mechanically complex. At Stockholm University, we have led the development of spiral-based and ring-nested designs for plasma haloscopes utilizing a single rotational axis. These resonator designs will be used for ALPHA and the first resonant dark photon search in Sweden. In this talk, I will discuss status of the ALPHA experiment and the current and future R&D at Stockholm University with regard to plasma haloscope resonator design.