<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Yes, that's exactly what I said. How does one get FLASH to use zbar? I just tried again after running setup with the added argument</div><div class="gmail_default" style="">-with-unit=physics/Eos/EosMain/Gamma<br></div><div class="gmail_default" style="">but I still get that d*T/P * kboltz/amu_cgs = 1.28 (= abar) instead of 0.612 (= abar/(1 + zbar)) like I would expect.</div><div class="gmail_default" style=""><br></div><div class="gmail_default" style="">Jon</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Sep 16, 2015 at 10:23 AM, Tomasz Plewa <span dir="ltr"><<a href="mailto:tplewa@fsu.edu" target="_blank">tplewa@fsu.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
Hi Jon -<br>
<br>
It is frequently assumed electron pressure is negligible compared to
ions, which is true for a nonionized gas. Obviously, the correct
formula should take into account contributions from both ions and
electrons. For a fully ionized gas, <br>
<br>
\mu = \frac{\sum_j n_j A_j }{\sum_j n_j ( 1 + Z_j) }<br>
<br>
Tomek<br>
--<div><div class="h5"><br>
<div>On 09/16/15 10:00, Jonathan Slavin
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Hi all,</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I'm doing
simulations aimed at understanding aspects of supernova
remnant evolution. Since the SNR is expanding the general
interstellar medium, the proper mean mass per atom (i.e.
neutrals and ions) is about 1.28 amu, given 90% H and 10% He
by number. As I understand it, this is set by the runtime
parameter eos_singleSpeciesA, which corresponds to abar. If I
want to assume constant, uniform, complete ionization then, as
I understand it, I need to set zbar via the runtime parameter
eos_singleSpeciesZ, to a value of ~1.091 = 1.2/1.1 = (n(H+) +
2*n(He++))/(n(H) + n(He)). At least that's what I thought
from the docs where at one point it's stated that n(e) =
zbar*n(ion). However, when I look at
density*temperature/pressure*kB/amu, I get abar. So it seems
that zbar is not used. What I expect is that</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">P = (1 +
zbar)/abar*kB*density*temperature</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Where P is the
total pressure (electron pressure + atom pressure). Is this
not true? Do I need to specify some extra unit for zbar to be
used (maybe -with-unit=physics/Eos/EosMain/Gamma)? Am I
misunderstanding the meaning of zbar? Any help would be
appreciated.</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Thanks,</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Jon</div>
<div><br>
</div>
-- <br>
<div>
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<div>
<div dir="ltr">________________________________________________________<br>
Jonathan D. Slavin Harvard-Smithsonian
CfA<br>
<a href="mailto:jslavin@cfa.harvard.edu" target="_blank">jslavin@cfa.harvard.edu</a>
60 Garden Street, MS 83<br>
phone: <a href="tel:%28617%29%20496-7981" value="+16174967981" target="_blank">(617) 496-7981</a> Cambridge, MA 02138-1516<br>
cell: <a href="tel:%28781%29%20363-0035" value="+17813630035" target="_blank">(781) 363-0035</a> USA<br>
________________________________________________________<br>
<br>
</div>
</div>
</div>
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</blockquote>
<br>
</div></div></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr">________________________________________________________<br>Jonathan D. Slavin Harvard-Smithsonian CfA<br><a href="mailto:jslavin@cfa.harvard.edu" target="_blank">jslavin@cfa.harvard.edu</a> 60 Garden Street, MS 83<br>phone: (617) 496-7981 Cambridge, MA 02138-1516<br>cell: (781) 363-0035 USA<br>________________________________________________________<br><br></div></div></div></div>
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