Magnetic fields in our galaxy: How much do we know? I. Disk fields within a few kpc of the Sun

The large scale magnetic fields of our Galaxy have been mostly revealed by rotation measures (RMs) of pulsars and extragalactic radio sources. In the disk of our Galaxy, the average field strength over a few kpc scale is about 1.8 muG, while the total field, including the random fields on smaller scales, has a strength of about 5 muG. The local regular field, if it is part of the large scale field of a bisymmetric form, has a pitch angle of about -8 degrees. There are at least three, and perhaps five, field reversals from the Norma arm to the outer skirt of our Galaxy.