Ultra high voltage op amp
I would consider using a resonant step up transformer (rather like what are used in a Tesla coil). You won't find any silicon amplifiers capable of running at this sort of voltage level so a magnetic solution seems your only viable option.



If you can drive 100 Vp-p into a step up transformer and get it to resonate at 10 MHz it should work AND be the likely easiest path to a solution BUT don't underestimate the skill, knowledge and perseverance in designing such a transformer. It will also be highly dangerous and it is likely you will need to oil dip the transformer to make it work.