There are a couple of articles which may be of interest to this group
which are on the astro-ph arXiv:
On the magnetic structure of the solar transition region,
by Philip G. Judge and Rebecca Centeno
http://arxiv.org/abs/0805.1436
An explanation of the solar transition region, by Philip G. Judge
http://arxiv.org/abs/0807.1706 (public access available tonight)
while the subjects may not seem to be concerned with coronal loops
they discuss the magnetic interface between the corona and chromosphere
including loop structures.
best wishes
Philip Judge