Meterwavelength Single-pulse Polarimetric Emission Survey II: The
  phenomenon of Drifting Subpulses
  A large sample of pulsars was observed as part of the Meterwavelength
Single-pulse Polarimetric Emission Survey. We carried out a detailed
fluctuation spectral analysis which revealed periodic features in 46% pulsars
including 22 pulsars where drifting characteristics were reported for the first
time. The pulsar population can be categorized into three distinct groups,
pulsars which show systematic drift motion within the pulse window, the pulsars
showing no systematic drift but periodic amplitude fluctuation and pulsars with
no periodic variations. We discovered the dependence of the drifting phenomenon
on the spin down energy loss ($\dot{E}$), with the three categories occupying
distinctly different regions along the $\dot{E}$ axis. The estimation of the
drift periodicity ($P_3$) from the peak frequency in the fluctuation spectra is
ambiguous due to the aliasing effect. However, using basic physical arguments
we were able to determine $P_3$ in pulsars showing systematic drift motion. The
estimated $P_3$ values in these pulsars were anti-correlated with $\dot{E}$
which favoured the Partially Screened Gap model of Inner Acceleration Region in
pulsars.
