Full Simulation of the Open Field Lines Above a Pulsar's Polar Cap. I. Acceleration
Abstract
We have programmed a full simulation of the open field lines above the polar cap of a magnetized pulsar using a time-dependent, particle-in-cell (PIC) numerical code. We consider the case of free ejection of electrons from the star surface, a space charge limited flow (SCLF) model. We report here the first results of the simulation. Electrons are accelerating along the open field lines according to the flat spacetime SCLF Lorentz-factor prediction, with an oscillation pattern. Then, we add the General Relativistic (GR) frame-dragging correction that provides the particles the high Lorentz factor (106-107) needed to initiate pair production. The electrons accelerate according to the GR Lorentz-factor prediction, with an oscillation pattern. Electron-positron pair production is now being programmed using cross-sections from the literature and the Monte Carlo code. After completing this stage, we will automatically get (1) the positron return current (thus, we can calculate polar cap heating and X-ray emission), (2) the photons' and electrons' observed spectra (photons and electrons that escape the magnetosphere after the cascade), (3) the pulsar death line (pulsars without enough pair production), (4) the PFF height (pair formation front location), and (5) the multiplicity (number of pairs produced per primary particle). Those results will be reported in a different paper.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 2011
- DOI:
- 10.1088/0004-637X/732/2/123
- arXiv:
- arXiv:1011.6330
- Bibcode:
- 2011ApJ...732..123B
- Keywords:
-
- acceleration of particles;
- magnetic fields;
- plasmas;
- pulsars: general;
- stars: neutron;
- Astrophysics - High Energy Astrophysical Phenomena;
- Physics - Plasma Physics
- E-Print:
- 7 pages, 6 figures