NB Uninsulated mains kills.
The whole circuit below is potentially at mains voltage.
If discharges are only occasional a transformer based 200V power supply makes sense.
There is NO way to charge a capacitor efficiently using resistive drop or wires that dissipate energy (= low ohm resistors) from a fixed supply voltage (Note "trick" below) .
To gain efficiency with a fixed source supply you MUST "boost" the voltage or "buck" the voltage using either capacitors standing on each other's shoulders techniques (usually not practical) or inductive energy transfer. Charging the capacitor at a voltage just in excess of its current voltage can achieve this. This can be from the output of a boost or buck converter BUT ...
A trick: Your input AC waveform assumes all voltage levels between 0 & 200 V
as it heads towards its 311 V peak. If the capacitor started off at 0 V and was then attached to mains at 0 V (via a diode or switch) then as the mains rose the capacitor would follow it. As main impedance will be lower than capacitor impedance this would be quite effective AS LONG AS your capacitor can tolerate the current required to charge in under a 1/4 cycle of mains. ie about 5 mS. What size is you capacitor?
You could do this over multiple cycles a burst at a time. Efficiency will drop
The capacitor may be kept charged efficiency" by connecting it to main occasionally as the mains voltage transits the capacitor voltage. This can be exciting if you get it wrong , and takes some head scratching but can probably be done with a few suitable voltage rated transistors and due thought.
This circuit works on a similar principle and you can get ICs that do this.
Here the FET is turned on by gate pulses from the mains BUT when Vmains rises too high the 2n2222 clamps the gate and keeps the FET off. This circuit would notionally solve yur whole task subject to suitably rated components. The gate would need to be zener clamped when you use such a high voltage. Needs more than usually careful thought.
What it does that's good:
When the cap is fully discharged the FET gate ispulled high via the 47k turning the FET on
Cout (why are there 2?) :-) - charges via FET. Cap voltage tracks mains volotage so efficincy is high. Cap charges in under 10 mS.
When V= raches 200V so Vcap ~= 200V then transistor base is at 200 x 1/331 ~= 0.6V
Transistor turns on clamping FET gate turning off FET so that cap stays at 200V.
If Vcap falls below 200V it will be "topped up.
As seen here loss in 47k at 200 V =~ 0.85 Watt = too high. A far more power effective gate circuit is possible with minimal power loss.
Hacked about it looks something like this:
Having started from this:
Here's a really fun buck converter solutin using an LNK304 IC about$1 /1 at Digikey
Data sheet above or application comment here