A Mechanism of Spark Motion in Inner Acceleration Region to Investigate Subpulse Drifting in Pulsars

Abstract

Coherent radio emission in pulsars is excited due to instabilities in a relativistically streaming non-stationary plasma flow, which is generated from sparking discharges in the inner acceleration region (IAR) near the stellar surface. A number of detailed works have shown the IAR to be a partially screened gap (PSG) dominated by non-dipolar magnetic fields with continuous outflow of ions from the surface. The phenomenon of subpulse drifting is expected to originate due to variable $\mathbf{E}\times \mathbf{B}$ drift of the sparks in PSG, where the sparks lag behind corotation velocity of the pulsar. Detailed observations show a wide variety of subpulse drifting behaviour where subpulses in different components of the profile have different phase trajectories. But the drifting periodicity is seen to be constant, within measurement errors, across all components of the profile. Using the concept of sparks lagging behind corotation speed in PSG as well as the different orientations of the surface non-dipolar magnetic fields we have simulated the expected single pulse behaviour in a representative sample of pulsars. Our results show that the different types of drifting phase behaviour can be reproduced using these simple assumptions of spark dynamics in a non-dipolar IAR.

22 pages, 19 figures, Accepted for publication in MNRAS

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Cited by in corpus (13)

• Rapid Modification of Neutron Star Surface Magnetic Field: A proposed mechanism for explaining Radio Emission State Changes in Pulsars
• Mode changing, subpulse drifting and nulling in four component conal pulsar PSR J2321+6024
• Nulling and subpulse drifting in PSR J1727-2739
• MeerKAT observations of the reversing drifting subpulses in PSR J1750-3503
• Two Dimensional Configuration and Temporal Evolution of Sparking discharges in Pulsars
• Meterwavelength Single-pulse Polarimetric Emission Survey. VI. Towards understanding the Phenomenon of Pulsar Polarization in Partially Screened Vacuum Gap model
• Estimating the evolution of Sparks in Partially Screened Gap of Pulsars from Subpulse Drifting
• Spectral variation across Pulsar Profile due to Coherent Curvature Radiation
• Radio Emission of Pulsars. II. Coherence Catalyzed by Cerenkov-Unstable Shear Alfvén Waves
• Individual pulse emission from the diffuse drifter PSR J1401$-$6357 using the ultrawideband receiver on the Parkes radio telescope
• Testing the circularity of PSR B0818-41's carousel
• Externally-driven plasma models as candidates for pulsar radio emission
• Independent discovery of a nulling pulsar with unusual sub-pulse drifting properties with the Murchison Widefield Array