Microwave plasma

With my modified microwave oven I can produce plasma in all kinds of gas discharge/ incandescent lamps. Because of the adjustable magnetron power I can do it without melting them after a few seconds.

Here I placed a neon bulb (one of those that flicker like a candle) inside the cooking cavity.
Note that these microwave experiments look far better "live". With our two eyes we can see the object from two slightly different angles and our brain "subtracts" the grid in the oven door from the picture.

I also found a good use for a dead HeNe laser tube. The laser wasn't nearly as bright when it still worked!

I got the most beautiful plasmas from incandescent lamps. As you can see the microwaved bulbs are no good for their intended use any more because their filaments melt. I suppose the filaments add some metal vapor to the argon atmosphere which enhances the optical effect.

I like the various colors. Beautiful!

The right foto is slightly overexposed. The discharge is not as bright as it looks here. The picture was taken at full power, this can only be done for a couple of seconds or the light bulb cracks.

Here I placed an evacuated (about 0.5 torr) preserving jar inside the cavity. The centers of the two upper plasma balls are spaced apart about 6cm which is half the wavelength of the microwaves. Thus the plasma makes the pattern of the standing waves visible. Cool.

With the microwave oven running at full power the plasma pattern becomes quite complex. I think it's because of absorption and reflection of the microwaves by the plasma. The plasma doesn't move by the way, it only changes its shape when oven power is changed.
Unfortunately the glass becomes quite hot and one jar already cracked.

Now I need a bigger jar...