|Joanna Rankin (University of Vermont)
| Radio pulsars have been known for nearly half a century, and they have become mainstay tools in several different areas of astrophysics. However, we still have only a rudimentary knowledge of how they work. Several of the foundational ideas that have guided attempts to understand their physics are probably incorrect.
Some recent observations and analyses show concretely that a pulsar is at root a plasma machine. In the inner regions near the star, the plasma is so dense and magnetized that EM waves cannot propagate; whereas most radiation that does reach us has been heavily processed by the more tenuous plasma at higher altitudes.
Key to understanding pulsar action, then, is investigating the properties of the so-called "core" radiation that comes from the lowest altitudes within the polar flux tube. This radiation we find propagates as the extraordinary mode and exhibits intensity-dependent aberration/retardation.