Pulsar Magnetospheres and Pulsar Death

摘要

Pulsars are rapidly spinning neutron stars whose lighthouse-like beams of radio waves sweep Earth, producing highly regular pulses with periods typically of order 1 s. Their spin periods gradually increase with time, and it was realized in 1968 that this must be due to the braking effect of a magnetic field some 10~12 times stronger than that of Earth (1). The rotation of the magnetic field causes the emission of magnetic dipole radiation, which exerts a torque that slows down the neutron star's rotation (2, 3),, It was suggested in 1969 that an additional braking torque is exerted by the outflow of the relativistic particles that produce the pulsed radio emission of the pulsar (4). Now, after 37 years and the discovery of over 1500 pulsars, clear evidence for the existence and strength of this "pulsar wind" torque has finally been found in the behavior of a highly peculiar pulsar, as described by Kramer et al (5) on page 549 of this issue This is an important breakthrough, because it gives quantitative information on the strengths of the magnetospheric electric currents that generate the pulsar's pulsed radiation.