6 research outputs found
The Appearance of a Radio-Pulsar Magnetosphere from a Vacuum with a Strong Magnetic Field. Accumulation of Particles
The accumulation of electrons and positrons in the vacuum magnetosphere of a
neutron star with a surface magnetic field of B~10^12 G is considered. It is
shown that particles created in the magnetosphere or falling into the
magnetosphere from outside undergo ultra-relativistic oscillations with a
frequency of 10-100 MHz. These oscillations decay due to energy losses to
curvature radiation and bremsstrahlung, with their frequencies reaching 1-10
GHz. Simultaneously, the particles undergo regular motion along the force-free
surface along closed trajectories. This leads to the gradual accumulation of
particles at the force-free surface and the formation of a fully
charge-separated plasma layer with a density of the order of the
Goldreich-Julian density. The presence of a constant source of
electron-positron pairs in the magnetosphere due to the absorption of energetic
cosmic gamma-rays leads to the growth of this layer, bringing about a rapid
filling of the pulsar magnetosphere with electron-positron plasma if the
pair-creation multiplication coefficient is sufficiently high.Comment: 22 pages, 2 figure
Absorption of Gamma-Ray Photons in a Vacuum Neutron Star Magnetosphere: I. Electron-Positron Pair Production
The production of electron-positron pairs in a vacuum neutron star
magnetosphere is investigated for both low (compared to the Schwinger one) and
high magnetic fields. The case of a strong longitudinal electric field where
the produced electrons and positrons acquire a stationary Lorentz factor in a
short time is considered. The source of electron-positron pairs has been
calculated with allowance made for the pair production by curvature and
synchrotron photons. Synchrotron photons are shown to make a major contribution
to the total pair production rate in a weak magnetic field. At the same time,
the contribution from bremsstrahlung photons may be neglected. The existence of
a time delay due to the finiteness of the electron and positron acceleration
time leads to a great reduction in the electron-positron plasma generation rate
compared to the case of a zero time delay. The effective local source of
electron-positron pairs has been constructed. It can be used in the
hydrodynamic equations that describe the development of a cascade after the
absorption of a photon from the cosmic gamma-ray background in a neutron star
magnetosphere.Comment: 29 pages, 1 figur