  We present a study of X-ray ionization of magnetohydrodynamic (MHD)
accretion-disk winds in an effort to constrain the physics underlying the
highly-ionized ultra-fast outflows (UFOs) inferred by X-ray absorbers often
detected in various sub-classes of Seyfert active galactic nuclei (AGNs). Our
primary focus is to show that magnetically-driven outflows are indeed
physically plausible candidates for the observed outflows accounting for the
AGN absorption properties of the present X-ray spectroscopic observations.
Employing a stratified MHD wind launched across the entire AGN accretion disk,
we calculate its X-ray ionization and the ensuing X-ray absorption line
spectra. Assuming an appropriate ionizing AGN spectrum, we apply our MHD winds
to model the absorption features in an {\it XMM-Newton}/EPIC spectrum of the
narrow-line Seyfert, \pg. We find, through identifying the detected features
with Fe K$\alpha$ transitions, that the absorber has a characteristic
ionization parameter of $\log (\xi_c [erg~cm~s$^{-1}$]) \simeq 5-6$ and a
column density on the order of $N_H \simeq 10^{23}$ cm$^{-2}$, outflowing at a
characteristic velocity of $v_c/c \simeq 0.1-0.2$ (where $c$ is the speed of
light). The best-fit model favors its radial location at $r_c \simeq 200 R_o$
($R_o$ is the black hole innermost stable circular orbit), with an inner wind
truncation radius at $R_{\rm t} \simeq 30 R_o$. The overall K-shell feature in
the data is suggested to be dominated by \fexxv\ with very little contribution
from \fexxvi\ and weakly-ionized iron, which is in a good agreement with a
series of earlier analysis of the UFOs in various AGNs including \pg.
