In 3D PIC simulations, how to determine the minimum required number of grid cells (nx, ny, nz) and the number of particles per cell (npart_per_cell)?

[xinyingyixia]

Dear friends,

Suppose my simulation box is 80 μm × 40 μm × 40 μm, the laser wavelength is 800 nm, and the target is a fully ionized water target (containing H, O, and electrons) with a thickness of 1 μm and a density of approximately 200 nc.

What are the possible methods to help determine the required grid resolution and the number of particles per cell? Note that this is a 3D EPOCH simulation.

Best regards,
Huihui