On the long and short nulls, modes and interpulse emission of radio
  pulsar B1944+17
  We present a single pulse study of pulsar B1944+17, whose non-random nulls
dominate nearly 70% of its pulses and usually occur at mode boundaries. When
not in the null state, this pulsar displays four bright modes of emission,
three of which exhibit drifting subpulses. B1944+17 displays a weak interpulse
whose position relative to the main pulse we find to be frequency independent.
Its emission is nearly 100% polarized, its polarization-angle traverse is very
shallow and opposite in direction to that of the main pulse, and it nulls
approximately two-thirds of the time. Geometric modeling indicates that this
pulsar is a nearly aligned rotator whose alpha value is hardly 2 degrees--i.e.,
its magnetic axis is so closely aligned with its rotation axis that its
sightline orbit remains within its conal beam. The star's nulls appear to be of
two distinct types: those with lengths less than about 8 rotation periods
appear to be pseudonulls--that is, produced by "empty" sightline traverses
through the conal beam system; whereas the longer nulls appear to represent
actual cessations of the pulsar's emission engine.
