Transformer – Microwave oven transformer, 2100v output.
C1 – Two microwave oven capacitors, total value around 2uF.
D1 – Two microwave oven diodes in series.
F1 – Variac protection fuse, around 5-10A.
This circuit has several different names – level shifter, voltage doubler etc. It outputs around twice the transformers voltage at halfwave dc, so I should be getting about 4-5kv out of it.