I know how,
just about every part of, a microwave oven works and
Then you'll know why the HV supply is almost invariably voltage
doubled AC and not rectified and smothed DC.
I know it is (the magnetron itself is one of the diodes in the doubler,
along with one capacitor and a semiconductor diode), but I don't actually
know _why_. Presumably it's to simplify the insulation of the transformer
or something.
-tony