This is 4" 150 watt 130 volt clear size G4 bulb.  It's sitting in a ceramic bowl, and a Pyrex cup with a small amount of water is to the left.  The water gives the microwave oven a 'load' (a place for the energy to go).  For this experiment, the turntable was turned over to keep it from rotating. 

The microwave was turned on for 10 seconds at a time.  The top of the globe gets quite hot, while the bottom remains cool.  So after each test, the globe was rotated about 90 degrees.

This bulb produced an excellent plasma field.  But after about 20 tests, one of the filament support wires melted.  The plasma generation diminished greatly after that.  A second bulb, same model and manufacturer, produced less spectacular results.  The reason for the difference in two seemingly similar bulbs is not clear.

Initially, the filament and support wires glowed.
In 2-3 seconds, a plasma arises from the filament area to the top of the globe. 

This photo was taken with the room lights off.  A pyrex cup with about 100ml of water is to the left.
Another plasma rising photo.  Room lights were on.
After becoming established, the plasma field seems to take energy that once went to the filament area.
Small differences in placement of the globe affect the intensity of the plasma field.