See this video of Scotty at Hawkeye applying the high voltage at 1:16:00 and following.
No name is given for the device except a high voltage transformer.
https://www.youtube.com/watch?v=PFnWYe5MzrY
I also seem to recall a name attached to the handheld device you're describing, but I don't remember it, even though we had one in the lab at Zenith.