I need to discharge a lot of current into an inductive load from a large capacitive bank. Ideally the current waveform would be as close to a flat-top as possible. Typically this seems to be done either by switching many caps in sequence using SCRs into a filter network to remove ripple or by simply using many caps to increase the power supply's time constant well beyond the required discharge time. I have toyed with the idea of using some sort of solid state regulator (e.g. zener based) but typical junction devices can't handle the currents I need (kiloamps). I know that large vacuum tubes are still manufactured for the radio industry etc. Would it be difficult to make a regulator or constant current source using a valve and some clever feedback? I have no idea where to start designing such a thing.