rt_stark.cpp

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/* This file is part of Cloudy and is copyright (C)1978-2022 by Gary J. Ferland and
 * others.  For conditions of distribution and use see copyright notice in license.txt */
/*RT_stark compute stark broadening escape probabilities using Puetter formalism */
#include "cddefines.h"
#include "iso.h"
#include "dense.h"
#include "phycon.h"
#include "rt.h"

STATIC realnum strkar( long nLo, long nHi );

void RT_stark(void)
{
        long int ipLo, 
          ipHi;

        double aa , ah, 
          stark, 
          strkla;

        DEBUG_ENTRY( "RT_stark()" );

        /* only evaluate one time per zone */
        static long int nZoneEval=-1;
        if( nzone==nZoneEval )
                return;
        nZoneEval = nzone;

        for( long ipISO=ipH_LIKE; ipISO<NISO; ++ipISO )
        {
                /* loop over all iso-electronic sequences */
                for( long nelem=ipISO; nelem<LIMELM; ++nelem )
                {
                        if( nelem >= 2 && !dense.lgElmtOn[nelem] )
                                continue;

                        t_iso_sp* sp = &iso_sp[ipISO][nelem];

                        if( !rt.lgStarkON )
                        {
                                for( ipHi=0; ipHi < sp->numLevels_max; ipHi++ )
                                {
                                        for( ipLo=0; ipLo < sp->numLevels_max; ipLo++ )
                                        {
                                                sp->ex[ipHi][ipLo].pestrk = 0.;
                                                sp->ex[ipHi][ipLo].pestrk_up = 0.;
                                        }
                                }
                                continue;
                        }

                        /* evaluate Stark escape probability from 
                         * >>ref Puetter Ap.J. 251, 446. */

                        /* coefficients for Stark broadening escape probability
                         * to be Puetters AH, equation 9b, needs factor of (Z^-4.5 * (nu*nl)^3 * xl) */
                        ah = 6.9e-6*1000./1e12/(phycon.sqrte*phycon.te10*phycon.te10*
                          phycon.te03*phycon.te01*phycon.te01)*dense.eden;

                        /* include Z factor */
                        ah *= powpq( (double)(nelem+1), -9, 2 );

                        /* coefficient for all lines except Ly alpha */
                        /* equation 10b, except missing tau^-0.6 */
                        stark = 0.264*pow(ah,0.4);

                        /* coefficient for Ly alpha */
                        /* first few factors resemble equation 13c...what about the rest? */
                        strkla = 0.538*ah*4.*9.875*(phycon.sqrte/phycon.te10/phycon.te03);

                        long ipHi = iso_ctrl.nLyaLevel[ipISO];
                        /* Lyman lines always have outer optical depths */
                        /* >>chng 02 mar 31, put in max, crashed on some first iteration 
                         * with negative optical depths,
                         * NB did not understand why neg optical depths started */
                        aa = (realnum)max(0.,sp->trans(ipHi,0).Emis().TauIn());
                        aa = powpq( aa, -3, 4 );
                        sp->ex[ipHi][0].pestrk_up = strkla/2.*MAX2(1.,aa);

                        sp->ex[ipHi][0].pestrk_up =
                                        MIN2(.01,sp->ex[ipHi][0].pestrk_up);
                        sp->ex[ipHi][0].pestrk_up = 0.;
                        sp->ex[ipHi][0].pestrk = sp->ex[ipHi][0].pestrk_up *
                                        sp->trans(ipHi,0).Emis().Aul();

                        /* >>chng 06 aug 28, from numLevels_max to _local. */
                        for( ipHi=3; ipHi < sp->numLevels_local; ipHi++ )
                        {
                                if( sp->trans(ipHi,0).ipCont() <= 0 )
                                        continue;

                                sp->ex[ipHi][0].pestrk_up = stark / 2. * 
                                        strkar( sp->st[0].n(), sp->st[ipHi].n() ) *
                                        powpq(MAX2(1.,sp->trans(ipHi,0).Emis().TauIn()),-3,4);

                                sp->ex[ipHi][0].pestrk_up = MIN2(.01,sp->ex[ipHi][0].pestrk_up);
                                sp->ex[ipHi][0].pestrk = sp->trans(ipHi,0).Emis().Aul()*
                                        sp->ex[ipHi][0].pestrk_up;
                        }

                        /* zero out rates above iso.numLevels_local */
                        for( ipHi=sp->numLevels_local; ipHi < sp->numLevels_max; ipHi++ )
                        {
                                sp->ex[ipHi][0].pestrk_up = 0.;
                                sp->ex[ipHi][0].pestrk = 0.;
                        }

                        /* all other lines */
                        for( ipLo=ipH2s; ipLo < (sp->numLevels_local - 1); ipLo++ )
                        {
                                for( ipHi=ipLo + 1; ipHi < sp->numLevels_local; ipHi++ )
                                {
                                        if( sp->trans(ipHi,ipLo).ipCont() <= 0 )
                                                continue;

                                        aa = stark *
                                                strkar( sp->st[ipLo].n(), sp->st[ipHi].n() ) *
                                                powpq(MAX2(1.,sp->trans(ipHi,ipLo).Emis().TauIn()),-3,4);
                                        sp->ex[ipHi][ipLo].pestrk_up = 
                                                (realnum)MIN2(.01,aa);

                                        sp->ex[ipHi][ipLo].pestrk = sp->trans(ipHi,ipLo).Emis().Aul()*
                                                sp->ex[ipHi][ipLo].pestrk_up;
                                }
                        }

                        /* zero out rates above iso.numLevels_local */
                        for( ipLo=(sp->numLevels_local - 1); ipLo<(sp->numLevels_max - 1); ipLo++ )
                        {
                                for( ipHi=ipLo + 1; ipHi < sp->numLevels_max; ipHi++ )
                                {
                                        sp->ex[ipHi][ipLo].pestrk_up = 0.;
                                        sp->ex[ipHi][ipLo].pestrk = 0.;
                                }
                        }
                }
        }

        return;
}

STATIC realnum strkar( long nLo, long nHi )
{
        return (realnum)pow((realnum)( nLo * nHi ),(realnum)1.2f);
}