Design of ALPHA Phase I: A Plasma Haloscope for 10–20 GHz Post-Inflation Axions

Abstract

The ALPHA collaboration is developing a plasma haloscope to search for QCD dark matter axions. This paper presents the design and projected sensitivity of ALPHA Phase I, targeting frequencies from 10 to 20 GHz (approximately 40–80 μeV). A tunable wire-array plasma resonator enables a large detection volume at frequencies where conventional microwave cavities become small.