  We estimate the constraining power of J-PAS for parameters of an interacting
dark energy cosmology. The survey is expected to map several millions of
luminous red galaxies, emission line galaxies and quasars in an area of
thousands of square degrees in the northern sky with precise photometric
redshift measurements. Forecasts for the DESI and Euclid surveys are also
evaluated and compared to J-PAS. With the Fisher matrix approach, we find that
J-PAS can place constraints on the interaction parameter comparable to those
from DESI, with an absolute uncertainty of about $0.02$, when the interaction
term is proportional to the dark matter energy density, and almost as good, of
about $0.01$, when the interaction is proportional to the dark energy density.
For the equation of state of dark energy, the constraints from J-PAS are
slightly better in the two cases (uncertainties $0.04$ - $0.05$ against $0.05$
- $0.07$ around the fiducial value $-1$). Both surveys stay behind Euclid but
follow it closely, imposing comparable constraints in all specific cases
considered.
