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Laxman,
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<div>You are correct that (for now) FLASH only accounts for absorption via inverse Bremsstrahlung. One way to increase absorption at low temperatures is to increase ms_targZMin. This often works fine for ns or longer pulses, giving reasonable energy deposition
and ablation, but short fs pulses may be more difficult to model with FLASH’s current capabilities.</div>
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<div>—</div>
<div><b>Eddie Hansen</b></div>
<div>Applications Group Leader</div>
<div>Flash Center for Computational Science</div>
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<div>On Oct 27, 2025, at 1:08 AM, Laxman Goswami <goswami.laxman@gmail.com> wrote:</div>
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<div><font size="4">Dear Users,<span class="gmail_default" style=""> </span></font></div>
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<div><font size="4"><font><span class="gmail_default" style=""></span></font>I am new to using FLASH simulations. Recently, I attempted to simulate the interaction of a femtosecond (fs) laser pulse with a helium (He) target. However, I observed very little
absorption of laser energy (approximately 0.008%).</font></div>
<p><font size="4">From my research, I found some suggestions indicating that FLASH may not be suitable for studying fs laser interactions, as it primarily accounts for Bremsstrahlung ionization.</font></p>
<p><font size="4">Could you please advise me on the correct approach to perform these simulations? Am I missing something in my setup, or is FLASH inherently limited for this type of problem?</font></p>
<p><font size="4">I would greatly appreciate any guidance or suggestions.</font></p>
<p><font size="4">Thank you for your time and help.</font></p>
<p><font size="4">Best regards,<br>
Laxman</font></p>
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