General questions

[floresv299]

Hello,

Thank you for the work on Lasy. I have been trying it, alongside Warpx and have some questions I was hoping someone can help with. The first one is on the parameter npoints; is this the number of points in the x,y,t dimensions that will also be used in the Warpx simulation? Do these numbers need to be equal the number of grid points in my Warpx simulation? Is increasing the number of points better or worse for my simulation? Another parameter that has been confusing is the t_peak, on paper I know what it is but conceptually I’m a little lost. I’m used to just having my laser be there without having this parameter. I know that when the value of t_peak is too low my gaussian profile starts at a high intensity and loses its shape. Is there a way to calculate t_peak so that my pulse is nice and gaussian ?

[IlianCS]

Hi @floresv299,
Thank you for your message.

The number of points is the number of grid points, in the given geometry extent, where the complex laser envelope which will be computed and stored in the lasy file for each x,y and t direction. It does not have to match the number of grid points in the WarpX simulation. That said, a very low value of the number of points will lead to approximate computation that may not correspond to the theoretical envelope.

t_peak corresponds to the time at which the laser envelope reaches its maximum amplitude. If you are looking at the begining of the simulation and notice that the Gaussian pulse is too short in time, you may want to set t_peak=0 and modify tau instead, which corresponds to the duration of the laser pulse.