Dielectric haloscopes: sensitivity to the axion dark matter velocity
  We study the effect of the axion dark matter velocity in the recently
proposed dielectric haloscopes, a promising avenue to search for well-motivated
high mass ($40-400~\mu$eV) axions. We describe non-zero velocity effects for
axion-photon mixing in a magnetic field and for the phenomenon of photon
emission from interfaces between different dielectric media. As velocity
effects are only important when the haloscope is larger than about 20% of the
axion de Broglie wavelength, for the planned MADMAX experiment with 80
dielectric disks the velocity dependence can safely be neglected. However, an
augmented MADMAX or a second generation experiment would be directionally
sensitive to the axion velocity, and thus a sensitive measure of axion
astrophysics.
