  Expanding on the comment by Lyne et al (2017), that intermittent pulsars tend
to congregate near a stripe in the logarithmic period versus period-derivative
diagram, representing a small range of polar cap electric potential, as well as
the fact (already apparent in their Fig.~7, but not explicitly stated there)
that high-fraction nulling pulsars also tend to reside within this and an
additional stripe, we make the observation that the two stripes further match
the "death lines" for double and single-pole interpulses, associated with
nearly orthogonal and aligned rotators respectively. These extreme inclinations
are known to suffer from pair production deficiencies, so we propose to explain
intermittency and high-fraction nulling by reinvigorating some older quiescent
(no pulsar wind or radio emission) "electrosphere" solutions. Specifically, as
the polar potential drops below the two threshold bands (i.e., the two
stripes), corresponding to the aligned and orthogonal rotators, their
respective magnetospheres transition from being of the active
pair-production-sustained type into becoming the electrospheres, in which
charges are only lifted from the star. The borderline cases sitting in the gap
outside of the stable regime of either case manifest as high-fraction nullers.
Hall evolution of the magnetic field inside orthogonally rotating neutron stars
can furthermore drive secular regime changes, resulting in intermittent
pulsars.
