"a mess of ley-lines, leptons, plasma fields"
"Ley-lines" refers to a New Age pseudoscientific belief in alignments between major monuments and geographical features. The lines could be used for dowsing, channeling of magical or psychic energy, or mapmaking. They featured in early issues of Hellblazer.
Leptons are a family of elementary particles involved in physics. "Plasma field" is incorrect jargon, but plasma is ionized gas which responds strongly to electromagnetic fields, as in a plasma lamp.
See maps of theoretical ley line locations at Vortex Maps
Find more information about leptons at the SLAC National Accelerator Laboratory site
Find more information about plasma at Plasmas.org