Photon Splitting and Pair Creation in Highly Magnetized Pulsars

By M. Baring, A. Harding. 2000

145 citations recorded by the source corpus.

The absence of radio pulsars with long periods has lead to the popular notion of a high-P "death line." In the standard picture, beyond this boundary, pulsars with low spin rates cannot accelerate particles above the stellar surface to high enough energies to initiate pair cascades, and the pair creation needed for radio emission is strongly suppressed. In this paper we explore the possibility of another pulsar "death line" in the context of polar cap models, corresponding to high magnetic fields B in the upper portion of the period-period derivative diagram, a domain where few radio pulsars are observed. The origin of this high-B boundary, which may occur when B becomes comparable to or exceeds Bcr = 4.4 × 1013 G, is also due to the suppression of magnetic pair creation, but primarily because of ineffective competition with magnetic photon splitting. Threshold pair creation also plays a prominent role in the suppression of cascades. We present Monte Carlo calculations of the pair yields in photon splitting/pair cascades that show that, in the absence of scattering effects, pair production is effectively suppressed, but only if all three modes of photon splitting allowed by QED are operating in high fields. This paper describes the probable shape and position of the new "death line," above which pulsars are expected to be radio-quiet, but perhaps still X-ray- and gamma-ray-bright. The hypothesized existence of radio-quiet sources finds dramatic support in the recent discovery of ultrastrong fields in soft gamma-ray repeaters and anomalous X-ray pulsars. Guidelines for moderate- to high-B pulsar searches at radio wavelengths and also in the soft and hard gamma-ray bands are presented.

Subfields: Astronomy and Astrophysics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/d0a11e52fa8c8a11d8be6ed4dd5f5030140ac342

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Michael Kramer
2. R. Manchester
3. G. Hobbs
4. Andrew G. Lyne
5. A. Harding
6. F. Camilo
7. Ingrid Stairs
8. A. Muslimov

In Statistical and Nonlinear Physics

1. G. Hobbs
2. R. Manchester
3. A. Muslimov
4. J. Arons
5. Michael Kramer
6. Andrew G. Lyne
7. A. Harding
8. D. Lai

Citations in the corpus

• Pulsar Polar Cap Heating and Surface Thermal X-Ray Emission. II. Inverse Compton Radiation Pair Fronts (2001, methodology): “The discrete QED treatment of the synchrotron emission in high magnetic fields (described above) is able to treat the effect of pair production in the ground Landau state, which also severely limits the number of pair generations in fields B >∼ 0.2Bcr (Baring & Harding 2001).”
• Physics of strongly magnetized neutron stars (2006, background): “However, the complete suppression of pair creation requires that both photon polarization modes undergo splitting (Baring and Harding 2001), but only the ⊥ mode splitting is allowed under Adler’s (1971) kinematic selection rules (section 5.6).”
• Nonlinear collective effects in photon-photon and photon-plasma interactions (2006, background): “Photon splitting can therefore play a significant role in these extreme systems (Baring and Harding, 2001; Harding, 1991).”
• The Parkes Multibeam Pulsar Survey – II. Discovery and timing of 120 pulsars (2002, background): “Baring & Harding (2001) propose that photon splitting may inhibit pair creation at these high magnetic fields and therefore hypothesize the existence of a boundary separating radio-loud and radio-quiet pulsars.”
• Magnetars in the Metagalaxy: An Origin for Ultra-High-Energy Cosmic Rays in the Nearby Universe (2002, background): “Magnetars are of particular interest as an acceleration site since (1) they exist (Kouveliotou et al. 1998, 1999; see the summary in Table 1 of Baring & Harding 2001) and (2) if they rotate fast enough sometime in their lives, they easily can have voltage drops well in excess of the energy per unit…”
• The Parkes Multibeam Pulsar Survey - VI. Discovery and timing of 142 pulsars and a Galactic population analysis (2006, background): “However, its implied dipole surface magnetic field is below the quantum critical limit (Baring & Harding 2001).”