Waaay back in history (late 1890s, early 1900s) we often see mention of "Oudin Coils". The definition (like "Tesla Coil") changed every decade since its creation, but the original concept was a space wound Tesla Coil of coarse wire powered from a 6 - 24" (!!) spark coil, typically an induction coil. The caps were generally Leyden Jars or Franklin Plates, and the frequencies were generally high compared to most Tesla Coils of that time period.
I experimented with a 286 turn secondary coil wound with a special extra-thick silk covered wire, embedded in resin.
Results were interesting...
http://www.electrotherapymuseum.com/2010/XRay006/index.htmAnd also...
http://www.electrotherapymuseum.com/2010/BipolarPhantom/xray.htmAlso tried some brief tests with a Pancake Coil:
http://www.electrotherapymuseum.com/2010/03Oct2010/interrupterless.htmDon't recommend trying this, its too dangerous. But for reference, this is what happens!
