"I am glad to present you a very simple experiment that you can conduct yourself with common material that you already have in your house. This experiment will allow you to see and check by yourself that a stable Plasmoid ( an artificial Plasma Ball ) can be created in air ( at a pressure of one atmosphere ). "

Weird microwave tricks. This is an old link, but a good one.

How to build a Stable Plasmoid at one atmosphere.