Analysis method for detecting topological defect dark matter with a
  global magnetometer network
  The Global Network of Optical Magnetometers for Exotic physics searches
(GNOME) is a network of time-synchronized, geographically separated, optically
pumped atomic magnetometers that is being used to search for correlated
transient signals heralding exotic physics. GNOME is sensitive to exotic
couplings of atomic spins to certain classes of dark matter candidates, such as
axions. This work presents a data analysis procedure to search for axion dark
matter in the form of topological defects: specifically, walls separating
domains of discrete degenerate vacua in the axion field. An axion domain wall
crossing the Earth creates a distinctive signal pattern in the network that can
be distinguished from random noise. The reliability of the analysis procedure
and the sensitivity of the GNOME to domain-wall crossings is studied using
simulated data.
