Previous
abstract 
Next abstract
The bulk of the energy lost by spinning, magnetized neutron stars is believed to carried off in a relativistic wind of particles and fields. The particle content of this wind is, however, very poorly known. Instances in which the pulsar wind interacts with surrounding material offer perhaps the best opportunities to unravel the wind physics and probe the underlying pulsar accelerator. We report here on analyses of optical/near-IR spectra of the the Crab pulsar's wind as it passes through the `wisps' and merges with the surrounding nebula. These wisps have been inferred to be the location of the termination shock of the freely expanding flow from the nebula. They represent a possible site for conversion of the high $\gamma$ output of the pulsar magnetosphere to the $\sigma \sim 0.003$, power-law energy distribution magnetized pair plasma believed to support the bulk of the Crab's continuum output. Spectral variation in the continuum synchrotron radiation through the wisps constrain the acceleration of the pairs which dominate the downstream plasma and can be used to probe for a possible baryonic component in the pulsar's accelerated particle beam.
