Toward Resolving the Crab σ-Problem: A Linear Accelerator?

摘要

Using the exact solution of the axisymmetric pulsar magnetosphere derived in a previous publication and the conservation laws of the associated MHD flow, we show that the Lorentz factor of the out- flowing plasma increases linearly with distance from the light cylinder. Therefore, the ratio of the Poynt- ing to particle energy flux, generically referred to as σ, decreases inversely proportional to distance from a large value (typically ≥10~4) near the light cylinder to σ≈1 at a transition distance R_trans. Beyond this distance, the inertial effects of the outflowing plasma become important, and the magnetic field geometry must deviate from the almost monopolar form it attains between R_lc and R_trans.