[FLASH-USERS] laser setup in cylindrical geometry

[Shu Zhang]

Hi Ke,

Your settings are correct. The 3D in 2D laser ray tracing is calculating the laser ray deflection and the energy deposition in 3D and then project the energy deposition on the 2D RZ coordinates. Thus, when the laser is injected in 45 deg, naturally the projected energy deposition is not really uniform. It would look like uniform if you have a planar target normal to the Z(Y) axis. 

-Shu

> On Sep 9, 2020, at 7:42 PM, 方可 <kfang at iphy.ac.cn> wrote:
> 
> Hi, everyone:
> 
> My simulation is using one laser beam irradiate on a spherical shell, and this laser beam have a 45 degree angle to x-axis. I used the cylindrical geometry, and from the output hdf5 files, I found that the intensity of laser is not symmetrically on the surface of the shell. But when i used the cartesian geometry with same 45 degree incident laser, the intensity on the shell is uniform and symmetrically.
> 
> I guess here are some problems when i'm seting up the laser beam. My laser setup in the .par file is as follows:
> 
> useEnergyDeposition = .true.
> ed_maxRayCount      = 20000
> ed_gradOrder        = 2
> 
> # Activate 3D-in-2D ray trace:
> ed_laser3Din2D           = .true.
> ed_laser3Din2DwedgeAngle = 0.1
> 
> ### LASER IO OPTIONS ###
> ed_useLaserIO                  = .true.
> ed_laserIOMaxNumberOfPositions = 10000
> ed_laserIOMaxNumberOfRays      = 128
> 
> ### SETUP LASER PULSES ###
> ed_numberOfPulses = 1 
> 
> # Define Pulse 1:
> ed_numberOfSections_1 = 4 
> 
> ed_time_1_1  = 0.0
> ed_time_1_2  = 0.01e-09
> ed_time_1_3  = 0.50e-09
> ed_time_1_4  = 0.51e-09
> 
> ed_power_1_1 = 0.0
> ed_power_1_2 = 1.52e+012
> ed_power_1_3 = 1.52e+012
> ed_power_1_4 = 0.0
> 
> 
> ### SETUP LASER BEAM ###
> ed_numberOfBeams = 1
> 
> # Setup Gaussian Beam:
> 
> ed_lensX_1                    =  10.0 
> ed_lensZ_1                    =  10.0
> ed_lensY_1                    =  0.0
> ed_lensSemiAxisMajor_1        =  3.0e-01
> 
> ed_targetX_1                  =  212.0e-04
> ed_targetZ_1                  =  212.0e-04
> ed_targetY_1                  =  0.0
> 
> ed_targetSemiAxisMajor_1      =  225.0e-04
> ed_targetSemiAxisMinor_1      =  225.0e-04
> 
> ed_pulseNumber_1              =  1
> ed_wavelength_1               =  0.351
> ed_crossSectionFunctionType_1 = "gaussian2D"
> ed_gaussianExponent_1         =  4.0
> ed_gaussianRadiusMajor_1      =  212e-04
> ed_gaussianRadiusMinor_1      =  212e-04
> ed_numberOfRays_1             =  4096
> ed_gridType_1                 = "radial2D"
> ed_gridnRadialTics_1          =  64
> ed_semiAxisMajorTorsionAngle_1=  0.0
> ed_semiAxisMajorTorsionAxis_1 = "x"
> 
> 
> And in mesh parameters:
> geometry = "cylindrical"  
> 
> And, this shell is a hollow spherical shell with outer radius 300 microns and inner radius 150 microns.
> 
> So, what should i do to let the intensity of the laser on the shell to be symmetrically to the 45 degree incident axis? 
> 
> Thank you for your attention and help !
> 
> Best regards,
> 
> Ke Fang
> 
> phd student
> Chinese Academy of Sciences

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