[FLASH-USERS] Flash LaserSlab ionmix

[Carlo Graziani]

Klaus is, of course, correct.  However, note that the ionization of Hydrogen
is a straightforward analytic solution of the Saha equations, requiring no
laborious computation.  If you Google "Saha equation Hydrogen" you'll get
260,000+ hits, many of the top of which are informative.  Many thermal physics
and stellar astrophysics texts also supply the solution.

Which is all by way of saying, if you don't want to mess around with the
internals of FLASH's EOS (and I wouldn't blame you if you didn't), it
should not be too much trouble to make your own IONMIX-style table for
Hydrogen, using the analytic solution.

Carlo

On 06/21/2017 02:29 PM, Klaus Weide wrote:
> On Wed, 21 Jun 2017, Siyi Yu wrote:
> 
>> Hey Klaus,
>> I am also trying to implement hytrogen ionization in my simulation. I am
>> wondering, instead of using IOMIX documents, is it possible to implement a
>> self-written function that calculates electron densities from temperature
>> please?
> 
> Hi Siyi,
> 
> In principle this is possible. Even in the best case, it will probably
> require some significant (re)writing of code. How much, and how difficult,
> will depend a lot on what you want to do. Some initial questions to narrow
> down your requirements:
> 
>   * Do you want to use this in 1T or in 3T (or RadFLAH?) simulations?
> 
>   * Do you Nele / ZBAR depend on only (density,temperature,composition),
>     or on additional independent variables? (maybe including time /
>     history?)
> 
>   * Do you just want one Eos implementation for all of your material(s),
>     or do you want an implementation that models just the behavior of the hydrogen
>     fraction in a multi-material, multi-type situation and can be combined
>     with other implementations for other materials?
> 
>   * Do you want an Eos that is thermally ideal or something more
>     complicated?
> 
>   * Do you need the derived quantities that Eos can potentially
>     provide - see Eos.h - and if yes, which ones, or would you be satisfied
>     (at least initially) with just getting the main variables
>     like EOS_PRES, EOS_EINT, EOS_TEMP returned correctly by Eos?
> 
> Klaus
> 


-- 
Carlo Graziani                                 (773) 702-7973 (Voice)
University of Chicago Astronomy                (773) 702-6645 (FAX)
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