CanγQuanta Really Be Captured by Pulsar Magnetic Fields?

Abstract

Recently it was pointed out by Shabad and Usov that in the vicinity of pulsars high-energy photons can be captured by the strong magnetic field without creating pairs. We have reconsidered this process and find that the captured "photon" is transformed into bound positronium. This positronium can be ionized by the intense electric fields present in the polar cap region, or by thermal radiation from the neutron star surface, whereby the free electrons and positrons are regained that are urgently required for the models of pulsar radio emission.

Electrodynamics of Magnetars. III. Pair Creation Processes in an Ultrastrong Magnetic Field and Particle Heating in a Dynamic Magnetosphere

“…We consider the conversion of resonantly scattered photons to pairs in x 2. After a short review of the process of direct pair creation by resonantly scattered X-rays, we examine the adiabatic conversion of gamma rays to bound positronium atoms in magnetic fields 10 13 G P B < 4B Q ¼ 1:8 ; 10 14 G. Near the threshold for pair creation, the electrostatic interaction between the electron and positron is relatively weak compared with the effects of vacuum polarization, in contrast with the case of sub-QED magnetic fields as examined by Herold et al (1985) and Shabad & Usov (1986). Nonetheless, we argue that an unbound pair does not form in the absence of a background flux of infrared or X-ray photons.…”

“…We highlight here some ambiguities in the existing treatments of this process ( Herold et al 1985;Shabad & Usov1986) when B k B Q . The associated refractive effects have been studied by Shabad & Usov (1984), who argue that the group velocity of the gamma ray will bend and asymptote to the local magnetic field.…”

“…The effects of this interaction on the gamma-ray dispersion curve have been analyzed by Herold et al (1985) and Shabad & Usov (1985) by calculating the vacuum polarization using the positive energy wave functions of the bound electron and positron in the magnetic field. There are, however, some ambiguities in this procedure when B > B Q .…”

“…The scattered gamma rays propagating through the curved magnetic field can be expected to convert adiabatically to bound electron-positron pairs (Herold et al 1985;Shabad & Usov 1986). We review this process and identify some peculiar features in super-QED magnetic fields.…”

Relativistic approach to positronium levels in a strong magnetic field

“…The year 1985 was marked by a number of papers, where the authors tried to take into account the positronium contribution into the dispersion equation of a photon which propagates in a superstrong magnetic field (Leinson & Oraevsky, [1], [2]); Herold et al, [3]; Shabad & Usov, [4]). Nevertheless, the correct solution of the completely relativistic problem for the bound states of an electron and positron in a superstrong magnetic field remains unknown.…”