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Abstract Pulsar radio emission may be generated in pair discharges that fill the pulsar magnetosphere with plasma as an accelerating electric field is screened by freshly created pairs. In this Letter, we develop a simplified analytic theory for the screening of the electric field in these pair discharges and use it to estimate total radio luminosity and spectrum. The discharge has three stages. First, the electric field is screened for the first time and starts to oscillate. Next, a nonlinear phase occurs. In this phase, the amplitude of the electric field experiences strong damping because the field dramatically changes the momenta of newly created pairs. This strong damping ceases, and the system enters a final linear phase, when the electric field can no longer dramatically change pair momenta. Applied to pulsars, this theory may explain several aspects of radio emission, including the observed luminosity,Lrad∼ 1028erg s−1, and the observed spectrum,Sω∼ω−1.4±1.0.
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Radio Emission and Electric Gaps in Pulsar Magnetospheres
Abstract The origin of pulsar radio emission is one of the old puzzles in theoretical astrophysics. In this Letter, we present a global kinetic plasma simulation that shows from first principles how and where radio emission can be produced in pulsar magnetospheres. We observe the self-consistent formation of electric gaps that periodically ignite electron-positron discharge. The gaps form above the polar cap and in the bulk return current. Discharge of the gaps excites electromagnetic modes, which share several features with the radio emission of real pulsars. We also observe the excitation of plasma waves and charge bunches by beam instabilities in the outer magnetosphere. Our numerical experiment demonstrates that global kinetic models can provide deep insight into the emission physics of pulsars and may help interpret their multiwavelength observations.
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- Award ID(s):
- 2009453
- PAR ID:
- 10474481
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal Letters
- Volume:
- 958
- Issue:
- 1
- ISSN:
- 2041-8205
- Format(s):
- Medium: X Size: Article No. L9
- Size(s):
- Article No. L9
- Sponsoring Org:
- National Science Foundation
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