We perform 2.5D axisymmetric simulations of the pulsar magnetosphere (aligned dipole rotator) using the charge conservative, relativistic, electromagnetic particle in cell code PICsar. The simulations are in the force-free regime except for dissipative regions at the polar caps, in the current layers, and at the Y-point. These dissipative regions arise self-consistently, since we do not have any explicit dissipation in the code. A minimum of $ \approx 20\%$ of the electromagnetic spindown luminosity is transferred to the particles in the dissipative regions, predominantly in the vicinity of the Y-point. The value of the spindown luminosity is in rough agreement with the force-free value, but can differ by tens of percent even when the characteristic magnetization at the light cylinder is high ($\sigma \sim 10^3-10^4$). This is because the magnetization in the vicinity of the Y-point is orders of magnitude lower than the characteristic magnetization at the light cylinder. As a result, particle inertia is important at the Y-point, and field lines are forced open there leading to a greater value of open magnetic flux and spindown luminosity compared to the force-free model.
Wed, 10 Dec 14
Comments: 8 pages, 6 figures, submitted to MNRAS