Hello! I have some electrons produced from a 3D gaussian source isotropically inside a uniform electric field. The electric field guides them towards a position sensitive detector and I end up with an image like the one below (with more electrons on the edge and fewer as you move towards the center). I want to run some simulations and for that I need to sample electrons from this 2D projection. Is there a functional form for this 2D distribution? Can someone point me towards some reading/Wikipedia page? Thank you!