  In vivo configurations of dsDNA of bacteriophage viruses in a capsid are
known to form hexagonal chromonic liquid crystal phases. This article studies
the liquid crystal ordering of viral dsDNA in an icosahedral capsid, combining
the chromonic model with that of liquid crystals with variable degree of
orientation. The scalar order parameter of the latter allows us to distinguish
regions of the capsid with well-ordered DNA from the disordered central core.
We employ a state-of-the-art numerical algorithm based on the finite element
method to find equilibrium states of the encapsidated DNA and calculate the
corresponding pressure. With a data-oriented parameter selection strategy, the
method yields phase spaces of the pressure and the radius of the disordered
core, in terms of relevant dimensionless parameters, rendering the proposed
algorithm into a preliminary bacteriophage designing tool. The presence of the
order parameter also has the unique role of allowing for non-smooth capsid
domains as well as accounting for knot locations of the DNA.
