The Growth of Cross Helicity in the Protogalactic Dynamo

摘要

The protogalactic dynamo theory of Kulsrud and coworkers raises the possibility that a strong magnetic field, which is coherent over galaxy-size length scales, emerges from a nonlinear turbulent dynamo during the protogalactic collapse. After galaxy formation, it is not clear that this galactic- scale field could be sustained by turbulence generated by supernovae because the turbulent stirring of supernovae is at the comparatively small length scale of 100 pc.