Characteristics of Emission Non-nulling Pulsars Through Simulation

We investigate the population and several properties of radio pulsars whose emission does not null(non-nulling)through simulation of a large pulsar sample. Emission from a pulsar is identified as non-nulling if(i) the emission does not cease across the whole pulse profile, and(ii) the emission is detectable. For(i), we adopt a model for switching in the plasma charge density, and emission persists if the charge density is non-zero. For(ii), we assume that detectable emission originates from source points where it is emitted tangentially to the magnetic field-line and parallel to the line-of-sight. We find that pulsars exhibiting non-nulling emission possess obliquity angles with an average of 42°.5, and almost half the samples maintain a duty cycle between 0.05 and 0.2. Furthermore, the pulsar population is not fixed but dependent on the obliquity angle, with the population peaking at 20°. In addition, three evolutionary phases are identified in the pulsar population as the obliquity angle evolves, with the majority of samples having an obliquity angle between 20° and 65°. Our results also suggest that emission from a pulsar may evolve between nulling and non-nulling during its lifetime.