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<p class="MsoNormal"><span lang="EN-US">Hi Kirill,</span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt">I am also trying to use the FLASH 4.7 code for a couple of laser produced plasma (LPP) application in 2D LaserSlab simulations in cartesian geometry.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt">For your first question, the third dimension of the laser spot size should be considered as unit length (1 cm) due to the laser cross-section function type “gaussian1D”. The laser beam intensity
in 3D cartesian should be adjusted or set the runtime parameter “ed adjustBeamsTargetIntensity” equal to true in 2D cartesian. I attached this part description from the FLASH 4.7 manual to let you know how to convert the laser intensity. I hope this could
help you. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt">For your second question, I also find some description about the “depo” variable and attached it but I am not sure whether it will help you.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt">By the way, I also have a question about how to add an external constant magnetic field during the LPP LaserSlab simulation. I would really appreciate it if you could provide some help.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt">Thanks.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt">Yaoxing Wu<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Sent from <a href="https://go.microsoft.com/fwlink/?LinkId=550986">
Mail</a> for Windows</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;font-family:SimSun"><o:p> </o:p></span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> flash-users <flash-users-bounces@flash.rochester.edu> on behalf of Kirill Lezhnin <klezhnin@princeton.edu><br>
<b>Sent:</b> Saturday, April 22, 2023 6:22:57 AM<br>
<b>To:</b> flash-users@flash.rochester.edu <flash-users@flash.rochester.edu><br>
<b>Subject:</b> [FLASH-USERS] Laser intensity in 2D cartesian LaserSlab</font>
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<div class="PlainText">---- External Email: Use caution with attachments, links, or sharing data ----<br>
<br>
<br>
Hi all,<br>
<br>
I am trying to use the FLASH code (in particular, the LaserSlab branch) for a couple of HEDP applications, and I would really appreciate it if you could help me to clarify a couple of things related to laser intensity in 2D LaserSlab simulations in cartesian
geometry.<br>
<br>
First: when I define laser pulse for the LaserSlab 2D cartesian simulation, I specify its intensity distribution in the simulation plane (by using cross-section function type “gaussian1D"). I wonder how should I interpret the third dimension (i.e., out of the
simulation plane) when calculating laser intensity on target from the power value given in the par file? Should I assume that laser intensity has the same distribution as the in-plane one? Or should I treat the third dimension as a uniform slab with the unit
thickness (like, 1 cm)? My current comparisons with inverse Bremsstrahlung absorption suggest that it is the latter, but it would be great to double-check it!<br>
<br>
Second: to compare my FLASH results to the PIC results with the laser energy deposition module, I’d like to calculate absorbed laser power density (i.e. quantity with the units of erg/s/cm^3). In FLASH, as far as I am aware, there is a ‘depo’ variable, which
calculates “amount of laser energy deposited in a cell per unit mass”, i.e. something like erg/g. I am not quite sure how to convert it to the power density I am looking for. My current assumption is that the deposited laser energy in depo variable is stored
for the last timestep, and then the absorbed power density = depo*dens / dt. Is my assumption correct?<br>
<br>
Thanks!<br>
<br>
Sincerely yours,<br>
Kirill Lezhnin<br>
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