rt_line_one_tauinc.cpp

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/* This file is part of Cloudy and is copyright (C)1978-2013 by Gary J. Ferland and
 * others.  For conditions of distribution and use see copyright notice in license.txt */
/*RT_line_one_tauinc increment optical depths for all heavy element lines, zone by zone,
 * mainly called by RT_tau_inc, but also by FeII */
#include "cddefines.h"
#include "doppvel.h"
#include "geometry.h"
#include "rfield.h"
#include "radius.h"
#include "wind.h"
#include "rt.h"
#include "physconst.h"
#include "cosmology.h"
#include "transition.h"

void RT_line_one_tauinc(const TransitionProxy&  t ,
        /* following four are flags to generate info if some species has extreme maser */
        long int maser_flag_species,
        long int maser_flag_ion,
        long int maser_flag_hi,
        long int maser_flag_lo,
        realnum DopplerWidth )

{
        DEBUG_ENTRY( "RT_line_one_tauinc()" );

        /* routine increments optical depths for static or expanding atmosphere */

        /* this is line center frequency, including bulk motion of gas */
        long int ipLineCenter = t.Emis().ipFine() + rfield.ipFineConVelShift;
        double OpacityEffective, EffectiveThickness;
        realnum dTau_total;

        /* find line center opacity - use fine opacity if array indices are OK */
        if( t.Emis().ipFine()>=0 && ipLineCenter>0 && ipLineCenter<rfield.nfine && rfield.lgOpacityFine )
        {
                /* use fine opacities fine grid fine mesh to get optical depth 
                 * to continuum source */
                /* total line center optical depth, all overlapping lines included */
                OpacityEffective = rfield.fine_opac_zone[ipLineCenter];
        }
        else
        {
                OpacityEffective = t.Emis().PopOpc() * t.Emis().opacity() / DopplerWidth;
        }

#if     0
        if( rfield.anu[ t.ipCont-1 ] < rfield.plsfrq )
        {
                /* transition is below plasma frequency - make optical depth huge */
                dTau_total = 1.e10;

                t.Emis().TauIn() = dTau_total;
                t.Emis().TauCon() = dTau_total;
                t.Emis().TauTot() = dTau_total;
        }
        else 
#endif
        if( cosmology.lgDo )
        {
                /* dv/dr (s-1), equal to dv/dt / v */
                /* in this case, dv/dr is just the Hubble factor */
                wind.dvdr = GetHubbleFactor(cosmology.redshift_current);

                fixit(); //This doppler width is sqrt(2kt/m), but Seager et al use sqrt(3kt/m).  Resolve
                EffectiveThickness = DopplerWidth / wind.dvdr;
                dTau_total = (realnum)(OpacityEffective * EffectiveThickness);
                
                t.Emis().TauIn() = dTau_total;
                t.Emis().TauCon() = dTau_total;
                t.Emis().TauTot() = dTau_total;
        }

        /* use cumulated fine optical depth for both d-critical and static, 
         * for d-critical speeds are only roughly sonic
         * optical depth is computed including velocity shift */
        else if( ! wind.lgBallistic() )
        {
                /* static and negative velocity solutions */
                EffectiveThickness = radius.drad_x_fillfac;
                dTau_total = (realnum)(OpacityEffective * EffectiveThickness);
                
                t.Emis().TauIn() += dTau_total;
                t.Emis().TauCon() += dTau_total;

        }

        else
        {
                /* ballistic outflowing wind
                 * effective length scale for Sobolev or LVG approximation, eqn 3 of
                 * >>refer      RT      wind    Castor, J.I., Abbott, D.C., & Klein, R.I., 1975, ApJ, 195, 157
                 */

                /* dv/dr (s-1), equal to dv/dt / v */
                wind.dvdr = fabs(wind.AccelTotalOutward - wind.AccelGravity) / wind.windv;
                /* depth (cm) over which wind accelerates by one velocity width
                 * include filling factor */
                EffectiveThickness = DopplerWidth / SDIV(wind.dvdr) * geometry.FillFac;

                /* min2 is to not let the physical scale exceed the current depth */
                EffectiveThickness = MIN2( radius.depth, EffectiveThickness );
                dTau_total = (realnum)(OpacityEffective * EffectiveThickness);
                
                t.Emis().TauIn() = dTau_total;
                t.Emis().TauCon() = dTau_total;
                t.Emis().TauTot() = dTau_total;
        }

        /* keep track of any masers */
        if( dTau_total < rt.dTauMase )
        {
                rt.dTauMase = dTau_total;
                rt.mas_species = maser_flag_species;
                rt.mas_ion = maser_flag_ion;
                rt.mas_hi = maser_flag_hi;
                rt.mas_lo = maser_flag_lo;
                if( rt.dTauMase < -1. )
                        rt.lgMaserCapHit = true;
        }

        return;
}