Ionization of Infalling Gas
  H-alpha emission from neutral halo clouds probes the radiation and
hydrodynamic conditions in the halo. Armed with such measurements, we can
explore how radiation escapes from the Galactic plane and how infalling gas can
survive a trip through the halo. The Wisconsin H-Alpha Mapper (WHAM) is one of
the most sensitive instruments for detecting and mapping optical emission from
the ISM. Here, we present recent results exploring the ionization of two
infallling high-velocity complexes. First, we report on our progress mapping
H-alpha emission covering the full extent of Complex A. Intensities are faint
(<100 mR; EM <0.2 pc cm^-6 but correlate on the sky and in velocity with 21-cm
emission. Second, we explore the ionized component of some Anti-Center Complex
clouds studied by Peek et al. (2007) that show dynamic shaping from interaction
with the Galactic halo.
