A Search for Dark Matter Axions with the Orpheus Experiment
  Axions are well motivated particles that could make up most or all of the
dark matter if they have masses below 100 $\mu$eV. Microwave cavity techniques
comprised of closed resonant structures immersed in solenoid magnets are
sensitive to dark matter axions with masses of a few $\mu$eV, but face
difficulties scaling to higher masses. We present the a novel detector
architecture consisting of an open, Fabry-P\'{e}rot resonator and a series of
current-carrying wire planes, and demonstrate this technique with a search for
dark matter axion-like particles called Orpheus. This search excludes dark
matter axion-like particles with masses between 68.2 and 76.5 $\mu$eV and
axion-photon couplings greater than $4\times10^{-7} \mathrm{GeV}^{-1}$. We
project that the fundamental sensitivity of this technique could be extended to
be sensitive to couplings below $1\times10^{-15} \mathrm{GeV}^{-1}$, consistent
with the DFSZ model of QCD axions.
