The CV54 from WW2
The peak envelope power of a pulse transmitter could, even in the early days of magnetrons, reach 0.5 megawatt or so. The short pulses of about 2 μs were repeated about 400 times a second. Thus the transmitter power on average was about 400 Watts. If the EHT line is 2,000 Volts, a mean current of 200 mA is required.
As the reservoir capacitor will be discharged into the modulator valve, the recharge will commence with a surge. A rectifier for this type of service will have a high peak output. This suggests a well proportioned cathode to supply the surge of electrons but a modest anode as the average power will be low.
See CV187, VU111 and AU5