  The curvature stress of DNA packed inside a phage is balanced against its
electrostatic self-interaction. The DNA density is supposed nonuniform and as a
result the Donnan effect is also inhomogeneous. The coarse-grained DNA density
is a nonlinear function of the DNA radius of curvature at a given position
inside the bacteriophage. It turns out that a region (or regions) exists
totally free from DNA. The size of such holes is computed.
