  We study the escape of Lyman continuum radiation from the disks of dwarf
starburst galaxies, with and without supershells, by solving the radiation
transfer problem of stellar radiation through them. We model disks with
Md=10^8-10Msun, with exponential surface density profiles as a function of
redshift, and model the of repeated supernova explosions driving supershells
out of the disks, using the hydrodynamic simulation code, ZEUS-3D. The amount
of star formation is assumed proportional to mass above some density threshold.
We vary the threshold to explore the range of star formation efficiencies,
f*=0.006, 0.06, and 0.6. We find that the interstellar gas swept up in dense
supershells can effectively trap the ionizing photons, before the supershells
blow out of the disks. The blow-outs then create galactic outflows, chimneys
which allow the photons to escape directly to the intergalactic medium. Our
results are consistent with escape fractions of less than 0.1 measured in local
dwarf starburst galaxies, because they are likely observed while the starbursts
are young, before blow-out. We suggest that high-redshift dwarf starburst
galaxies may make a substantial contribution to the UV background radiation
with total escape fractions >0.2, as expected if star formation efficiencies
>0.06.
