A statistical determination of the location of emission in pulsars based on a new classification

83 pulsars are statistically studied in this paper. The main results are as follows:

• 1.

  (1) Taking the ratio λ of the loss rate of rotational energy to the radio luminosity of pulsars as a parameter of classification, we divide the 83 pulsars into 3 categories. The plots of $\text{P}\text{dot}\text{-P, L}{}_{\mathrm{<mtext>radio</mtext>}}\text{-P}\text{and}\text{L}{}_{\mathrm{<mtext>radio</mtext>}}\text{-t}$ show that different categories of pulsars have different evolutionary tracks and physical properties. The evolutionary tracks of our 3 categories are similar to those of the model proposed by Lyne et al. (1975) [1] which involves a secular decay of magnetic dipole moment, suggesting that the different categories have different time constants of decay, or different initial values of magnetic moment at birth.

• 2.

  (2) The radio luminosities of pulsars of various categories are all closely correlated with the magnetic energies and “twining” magnetic energies at the light cylinder, and not correlated with the magnetic energies at the surface of the neutron star. This shows that localized radiation regions are in the vicinity of the light cylinder. These magnetic energies may be the energy sources of pulsar radiation.

• 3.

  (3) The rightmost pulsars in the $\text{P}\text{dot}\text{-P}$ plot form a cut-off line of radio radiation, with a slope of −4, so that it is a line of constant “twining” magnetic energy. This line is closer to the observational results than the cut-off line, proposed by Lyne et al. (1975) [1], with a gradient of −5. This results gives support to the idea that energy is accumulated and released in the vicinity of the light cylinder.