I would love to perform experiments that make spherical sparks! Alas, I do not have the money for it at this time. I've tried to perform such experiments with a low cost DC arc welder but have not been successful. It simply doesn't have the juice.
However, I saw a television documentary -- I have not been able to find out its name -- that talked about a scientist in the US who has a large number of old submarine batteries and uses these batteries to create and study spherical sparks. In the show, he hypothesized that the sparks might be a form of Ball Lightning. The Ball-of-Light Particle Model predicts that assumption is correct. I believe the scientist may have had a name like "Golka", but I am not sure.
(If you have information on this show, please E-mail me. Or, if possible, please send me a videotape to PO Box. I would really appreciate it.)