Magnetic fields in high energy astrophysical sources: A selection of physical processes and consequences

This study encompasses a selection of particle acceleration processes and astrophysical phenomena associated with systems in which magnetic fields play a central role. In particular: (1) The well-studied process of annihilation of magnetic energy by magnetic reconnection has been generalized for strongly magnetized relativistic plasmas. (2) A generalized version of Ohm's law for a relativistic pair plasma has been uncovered during this investigation. (3) A further look at the physics of reconnection has revealed that power law acceleration can be associated directly with reconnection shocks. This is consistent with the observed association of magnetically active regions with power law spectra, including jets of active galaxies. (4) The importance of magnetic topology in active galactic nuclei initiated a consideration of the dynamo mechanism for generating these fields. This has led to a new derivation of the mean field growth equation which relaxes some standard assumptions in the context of recent controversy over the dynamo theory. (5) Finally, since jets occur on stellar as well as galactic scales, trying to understand analogies between jet processes on these different scales has led to a new model for gamma-ray bursts which appeals to a magnetized pulsar jet that precesses past the line of sight.