Slide 33 of 59
Notes:
Particles are able to move along, but not across, the magnetic field lines. In this model, the plasma is ‘carried along’ with the neutron star in the equatorial regions (ie. It co-rotates with the star). Streams of charged particles leave the star at high latitudes where the field lines are open.
Of course the plasma can co-rotate with the neutron star only out to the radius at which v=c (at larger radii, v exceeds c which is impossible). This radius R_L defines the ‘light cylinder’ and satisfies the condition (2*pi*R_L)=c.
Substituting (P=0.033 secs) and re-arranging, for the Crab pulsar, R_L, the radius of the light cylinder, is 1,600 km.