[FLASH-USERS] [EXT] Re: Laser across a 1D domain

[Kurzer-Ogul, Kelin]

Hi Zach,

Is there a reason you can't just use r-z (2D) geometry with outflow boundary conditions on the z-axis? Hopefully I'm not making a fool of myself by saying this but I believe that would be equivalent to a semi-infinite z domain.

Best,
Kelin Kurzer-Ogul
________________________________
From: flash-users-bounces at flash.uchicago.edu <flash-users-bounces at flash.uchicago.edu> on behalf of Zach Barfield <zachbarfield60 at gmail.com>
Sent: Monday, August 16, 2021 8:44:17 AM
To: David Blackman <drblackman at eng.ucsd.edu>
Cc: flash-users <flash-users at flash.uchicago.edu>
Subject: Re: [FLASH-USERS] [EXT] Re: Laser across a 1D domain

Eddie's description is correct. Apologies for the lack of clarity.

I have been working in 2D cylindrical prior to this. My problem is the finite size of the z-dimension, I would like to avoid this issue. My understanding of this simulation space is that by restricting my domain to 1D (radius) I can approximate an infinitely-long axial dimension.

It is not clear to me how the absorption physics would be calculated without dimension perpendicular to the radius.

-Zach

On Mon, Aug 16, 2021 at 11:35 AM David Blackman <drblackman at eng.ucsd.edu<mailto:drblackman at eng.ucsd.edu>> wrote:

Yeah, that also make sense, as simulating he plasma expanding laterally through the lasers radial beam profile. It still makes more sense to do that as a 2D cylindrical simulation though surely? Would the absorption physics even work like that in 1D?

On 16/08/2021 08:26, Eddie Hansen wrote:
If I understand correctly, the objective is to have a laser that travels in the axial direction (perpendicular to the radius), and the beam has a radial profile. He wants to simulate in 1D cylindrical and observe plasma expansion radially.

On Mon, Aug 16, 2021, 10:13 AM David Blackman <drblackman at eng.ucsd.edu<mailto:drblackman at eng.ucsd.edu>> wrote:

I'm not sure I understand exactly what you are trying to do. What you asking doesn't seem to make sense. The laser will travel along the radius, yet your super Gaussian profile will be spatially varying at 90 degrees to the radius, and you want to do it in 1D. I suspect you want a polar geometry with the laser traveling in from the radius, right?

Maybe look at the 2D laser slab? You might be able to put something together with cylindrical geometry, you could model it as a circle arc at the end of a tube with the laser coming in from the longitudinal direction maybe? Otherwise a well refined Cartesian grid might be better.

On 16/08/2021 07:59, Thibault Goudal wrote:
Hello,
just to contribute to the conversation, in the example1d.par, the geometry is cartesian. I haven't seen explicitely a flash.par input deck including 1D spherical geometry and laser energy deposition.
I'm not sure that it's possible so far unless mimicing a spherical geometry with cartesian/cylindrical mesh but not confident of catching the physics accurently.

________________________________
De: "Zach Barfield" <zachbarfield60 at gmail.com><mailto:zachbarfield60 at gmail.com>
À: "Andy Sha Liao" <andy at f.energy><mailto:andy at f.energy>
Cc: "flash-users" <flash-users at flash.uchicago.edu><mailto:flash-users at flash.uchicago.edu>
Envoyé: Lundi 16 Août 2021 16:39:16
Objet: Re: [FLASH-USERS] Laser across a 1D domain

Yes,
In example1d.par the laser is a single ray that propagates along the radius. I am interested in sending a spatially-varying (supergaussian) laser across the radius.

-Zach

On Mon, Aug 16, 2021 at 10:20 AM Andy Sha Liao <andy at f.energy><mailto:andy at f.energy> wrote:
Zach,

Have you looked at example1d.par in LaserSlab?


Andy

On Mon, Aug 16, 2021 at 9:05 AM Zach Barfield <zachbarfield60 at gmail.com<mailto:zachbarfield60 at gmail.com>> wrote:
Hello all,
Does anyone know how to simulate a laser impinging across the radius of a 1D radial domain?
It seems to me that FLASH has no capability of including dimensionality in the laser beam when using a 1D geometry, is this true?

I am using a 1D radial domain because I would like to simulate the laser heating of a cylinder of gas with an approximately infinite z-dimension. I am only interested in the temporal evolution of the radial profile.

Cheers,
Zach Barfield

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