You'll have done a Gooogle search by now, surely, for - say - "Microwave bulb"
These may help:
https://www.youtube.com/results?search_query=Toshiba+delta+wave+replace+bulb
Be VERY careful. Microwave ovens include large capacitors that can retain enough charge to kill, even when the oven is off.
yw5w4y, November 2017