Earliest Microwave Oven Plasma

Who first made "ball lightning" in the microwave oven? Bill Beaty links to an old Usenet posting here: http://amasci.com/tesla/mwball.txt that takes us back to 1997. This of course was the dark ages, using birthday candles and chared toothpicks. Some time back, I discovered a reference to a microwave oven plasma from at least the 1960's!

I remember reading Philip Klass's UFOs Identified in high school. I think it appealed to my growing skepticism. UFOs Identified was Philip J. Klass' first book, in which he explored the possibility that at least some UFO sightings could be due to natural or man made atmospheric plasmas. I don't follow the UFO field carefully, but I understand Klass himself moved away from this hypothesis as time went on. Unfortunately, Klass is somewhat vague on details in his treatment of this event, but it suggests that microwave ovens were accidently creating plasmas long before 1997!

The following is from Philip J. Klass UFOs Identified Random House 1968 Library of Congress Catalog Card Number 67-22622 page 151-152:

"Next I called Dr. Finkelstein, who told me that a "synthitic kugelblitz" was being produced by Dr. James R. Powell at the Atomic Energy Commissions Brookhahaven National Laboratory in Upton, Long Island. The laboratory was using equipment originally built to enable bakeries to quickly defrost frozen bread, as well as for other industrial applications. How amusing, I thought, the AEC using bakery equipment to produce kugelblitz!

The equipment is a special type of oven whose heat is produced by radio-frequency energy supplied by a transmitter similar to those usen in television stations. The "Macrowave Oven," as it is called, is made by Radio Frequency Company, Incorporated, of Medfield Massachusetts. It is an aluminum box, nearly seven feeti in each dimension, fed by the radio transmitter. The dimensions are chosen to be equal to one-half the wavelength of the radio waves, which serves to intensify the heating. In technical terms, the metal box is a "tuned cavity."

One day, during the final tests of an oven, and engineer was amazed to see a ball of plasma suddenly form inside the oven. The synthetic kugelblitz, nearly a foot in diameter, hovered and floated mysteriously until power was shut off; then it collapsed and disappeared. The glowing plasma ball reminded the company's president, Joshua G.D. Manwaring, of some of the UFO reports he had read and he later tried to interest several newspapers in the idea that similar natural plasmas might explain some UFOs. But no one was interested in the idea, Manwaring told me.

Seeking an explanation for the phenomenon, Manwaring finally got in touch with Dr. Powell at Brookhaven. The laboratory agreed to send up a cameraman to make high-speed mivies of the plasma. When Powell saw the movies, he promptly ordered one of the Macrowave Ovens."

We are not told what kind of material was in the oven when this event occured. Could it have been bread that had become toasted then charred? We know that the early Usenet folks used charred toothpicks to initiate plasmas, could the same thing have happened with bread?

I'm going to guess the plasma was not contained. If you don't contain the plasma, it will float up to the ceiling of your microwave oven and start burning it. Obviously no mention of that is given!