[FLASH-USERS] problem with spatial distribution of laser rays

[Reyes, Adam]

Hi Antoine,

I think this might be related to using the 2Din3D ray tracing combined with a radial grid for the rays. On a 2D radial grid, with points equally spaced in radius and angle the density of rays will be higher closer to r=0, and so the laser power is distributed amongst a larger number of rays, so the individual rays will have less power than farther away. You might be able to account for this by weighing the ray power by a factor of 1/r to account for the change in ray density.

 You can see that the energy deposition in your plot seems to match the expected profile.

Adam

On Feb 23, 2022, at 11:19 AM, Antoine Gintrand <antoine.gintrand at gmail.com<mailto:antoine.gintrand at gmail.com>> wrote:

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Antoine Gintrand <antoine.gintrand at gmail.com<mailto:antoine.gintrand at gmail.com>>
[Pièces jointes]17:34 (il y a 2 heures)
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À flash-users
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Dear flash users,

I have a problem concerning the spatial distribution of my laser rays.
The laser is supposed to come from the top with no angle
and hit the target  at z = 400 microns with a gaussian spatial profile
I(r) = exp (-(r/R)^gamma) where gamma = 4.
The rest of the domain is a 100 microns low density vacuum at the top.

Unfortunately the centre of the gaussian is not in r = 0. Why so?
I do not understand because I put the center of the gaussian to
be ed gaussianCenterMajor_1 = 0. and ed_gaussiancenterMinor_1 = 0.
I am using 3Dto2D laser ray tracing.

Here is attached my .par file and .log and a plot of the depo var + rays power.

Thank you very much for any help on this,

All the best,

Antoine
<depo_nofoam_t50ps.png><flash.par><lasslab.log>_______________________________________________
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