  LkCa 15 hosts a pre-transitional disk as well as at least one accreting
protoplanet orbiting in its gap. Previous disk observations have focused mainly
on the outer disk, which is cleared inward of ~50 au. The planet candidates, on
the other hand, reside at orbital radii around 15 au, where disk observations
have been unreliable until recently. Here we present new J-band imaging
polarimetry of LkCa 15 with SPHERE IRDIS, yielding the most accurate and
detailed scattered-light images of the disk to date down to the planet-hosting
inner regions. We find what appear to be persistent asymmetric structures in
the scattering material at the location of the planet candidates, which could
be responsible at least for parts of the signals measured with sparse-aperture
masking. These images further allow us to trace the gap edge in scattered light
at all position angles and search the inner and outer disks for morphological
substructure. The outer disk appears smooth with slight azimuthal variations in
polarized surface brightness, which may be due to shadowing from the inner disk
or a two-peaked polarized phase function. We find that the near-side gap edge
revealed by polarimetry matches the sharp crescent seen in previous ADI imaging
very well. Finally, the ratio of polarized disk to stellar flux is more than
six times larger in J-band than in the RI bands.
