  Both physical arguments and simulations of the global heliosphere indicate
that the tailward heliopause is flattened considerably in the direction
perpendicular to both the incoming flow and the large-scale interstellar
magnetic field. Despite this fact, all of the existing global analytical models
of the outer heliosheath's magnetic field assume a circular cross section of
the heliotail. To eliminate this inconsistency, we introduce a mathematical
procedure by which any analytically or numerically given magnetic field can be
deformed in such a way that the cross sections along the heliotail axis attain
freely prescribed, spatially dependent values for their total area and aspect
ratio. The distorting transformation of this method honors both the
solenoidality condition and the stationary induction equation with respect to
an accompanying flow field, provided that both constraints were already
satisfied for the original magnetic and flow fields prior to the
transformation. In order to obtain realistic values for the above parameters,
we present the first quantitative analysis of the heliotail's overall
distortion as seen in state-of-the-art three-dimensional hybrid MHD-kinetic
simulations.
