An analysis of high-resolution Stokes observations of two light bridges
in active region NOAA 8990 is presented. The observations were recorded
with the La Palma Stokes Polarimeter attached to the Swedish Vacuum
Solar Telescope. The stratification over the solar atmosphere of different
physical parameters is retrieved from these data using the Stokes Inversion
based on response functions (SIR). Our results confirm previous
observations of features such as
the decrease in magnetic field strength and the increase in inclination in the
light bridges. We also confirm a temperature increase in these structures with respect to the surrounding umbrae.
The maps of the magnetic field strength and of the orientation of the magnetic field vector indicate
the presence of a canopy structure above the light bridges.
We derive the vertical component of electric current density
($J_z$) from the configuration of the magnetic field. The increased
temperature found in the upper layers is studied in the
context of the proposed canopy topology and could also explain the recently observed
chromospheric heating processes found above light bridges.