  The magnetic field in the local interstellar medium does not follow the
large-scale Galactic magnetic field. The local magnetic field has probably been
distorted by the Local Bubble, a cavity of hot ionized gas extending all around
the Sun and surrounded by a shell of cold neutral gas and dust. However, so far
no conclusive association between the local magnetic field and the Local Bubble
has been established. Here we develop an analytical model for the magnetic
field in the shell of the Local Bubble, which we represent as an inclined
spheroid, off-centred from the Sun. We fit the model to Planck dust polarized
emission observations within 30 deg of the Galactic poles. We find a solution
that is consistent with a highly deformed magnetic field, with significantly
different directions towards the north and south Galactic poles. This work sets
a methodological framework for modelling the three-dimensional (3D) structure
of the magnetic field in the local interstellar medium, which is a most awaited
input for large-scale Galactic magnetic field models.
