  In disk wind models for active galactic nuclei (AGN) outflows, high-energy
radiation poses a significant problem wherein the gas can become overionized,
effectively disabling what is often inferred to be the largest force acting on
the gas: the radiation force due to spectral line opacity. Calculations of this
radiation force depend on the magnitude of ionizing radiation, which can
strongly depend on the position above a disk where the radiation is
anisotropic. As our first step to quantify the position and direction
dependence of the radiation field, we assumed free streaming of photons and
computed energy distributions of the mean intensity and components of flux as
well as energy-integrated quantities such as mean photon energy. We find a
significant dependence of radiation field properties on position, but this
dependence is not necessarily the same for different field quantities. A key
example is that the mean intensity is much softer than the radial flux at many
points near the disk. Because the mean intensity largely controls ionization,
this softening decreases the severity of the overionization problem. The
position dependence of mean intensity implies the position dependence of gas
opacity, which we illustrate by computing the radiation force a fluid element
feels in an accelerating wind. We find that in a vertical accelerating flow,
the force due to radiation is not parallel to the radiation flux. This
misalignment is due to the force's geometric weighting by both the velocity
field's directionality and the position dependence of the mean intensity.
