  Galactic winds probe how stellar feedback regulates the mass and metallicity
of galaxies. Observations show that galactic winds are multiphase and
magnetised. In the local Universe, the dense phase is traced by emission and
absorption lines, which reveal the presence of fast-moving clouds embedded in
hot streams. Simulations tell us that magnetic fields can shield such clouds
and delay their disruption, but there is little discussed on their
observational effects. Using 3D MHD simulations, we study the influence of two
orientations of the magnetic field (aligned and transverse) on the cloud
morphology, temperature and density structure, mixing fraction, ion kinematics,
column densities, and absorption spectra. We study supersonic wind-cloud
systems with radiative processes, and develop a framework to extract ion column
density maps and synthetic absorption spectra. The framework relies on studying
ion populations and creating down-the-barrel spectra via an interface that
links our PLUTO simulations to TRIDENT using YT, CLOUDY, and STARBURST99. We
find that the transverse magnetic field makes the cloud asymmetric, shields and
protects dense cold gas, and reduces mixing fractions compared to the aligned
case. Ions can reach higher velocities in the transverse field case. The
imprints of the initial orientation of the field on the synthetic spectra are:
in the cold phase we find no signature of C ii and Si ii when the field is
aligned, in the intermediate phase traced by C iv and Si iv we find broader
lines in the transverse case, and in the warm phase we find deeper lines for O
vi and N v in the aligned case, but they are less sensitive to the field
orientation. Magnetic fields significantly affect the absorption spectra of
cold clouds. Intermediate ions are the most sensitive to the magnetic field
orientation and can potentially yield information about magnetic field
topology.
