Using a MOSFET to switch a High Voltage on a Capacitive Load
There's a few different issues/comments I see with this. 


That's a 600V MOSFET and you're planning on using it at 575V. I'd say use a >= 900V MOSFET to be safe.
You show an inverting op-amp to get a negative voltage, but it isn't clear at all that you have a negative voltage supply (e.g. -10V). If you don't have that negative supply, your circuit will not work.
You probably want to drive the MOSFET with a decent on voltage, like -10V or more. Note that the RDS(on) is specified at a Vgs of -10V. That transistor is barely on at -5V. That means your inverting amplifier should have a gain of -4 or so from a TTL output (2.6V). 
Some Op-amps don't like driving a capacitive load (like a MOSFET gate)
You may want a gate resistor
This will not switch the MOSFET quickly, but I don't see that as an issue as long as you aren't switching the power on and off frequently. Since the MOSFET is effectively dissipating the energy stored in the capacitive load, I don't think that's an issue.
If the capacitance is large (or you need to switch the load very frequently), you may need a resistor in series with the drain to dissipate the power. At that point, switching speed becomes important. Note that the energy stored in a capacitor is \$ Energy = \dfrac{1}{2} \cdot C \cdot V^2\$.


My overkill approach would probably be to get an isolated DC-DC converter, a digital signal isolator IC (optical or otherwise), and a gate driver. Of course at that point you could also probably use a NFET.