title Ly alpha forest cloud
c
c commands controlling continuum =========
c ionized by cosmic background
c plus quasar/starburst continuum 
// background, z=2 ; this includes both black body and AGN parts
// >>chng 05 aug 29, from background to cmb plus hm05 to test hm05
cmb z=2
table hm05 z = 2
c
c commands for density & abundances =========
hden -2
metals -1.5  ;reduce all heavy elements by 1.5 dex
c
c commands controlling geometry  =========
stop neutral column density 15
double  ; mimic two-siced photoionization
c
c other commands for details     =========
iterate to convergence; must iterate since optically thin
c
c commands controlling output    =========
print line faint -1
save performance "igm_lalpha.per"
save overview last "igm_lalpha.ovr"
save dr last "igm_lalpha.dr"
save results last "igm_lalpha.rlt"
c
c commands giving the monitors    =========
c on 05 aug 29 changed from old background command to
c cmb 2 plus hm05 z=2 background - all results changed substantially
monitor thickness 19.721
monitor temperature hydrogen 2 4.270
monitor ionization hydrogen 1 -2.721
monitor ionization Helium 1 -2.726
monitor ionization Helium 2 -0.236
monitor ionization Helium 3 -0.380
//
// >>chng 06 nov 29, from -3.939 to -4.007, Badnell DR turned on
monitor ionization Oxygen 1  -4.007
// 
// >>chng 06 nov 29, from -1.239 to -1.300, Badnell DR turned on
monitor ionization Oxygen 2  -1.300
// 
monitor ionization Oxygen 3  -0.096
// 
// >>chng 06 nov 29, from -0.865 to -0.785, Badnell DR turned on
monitor ionization Oxygen 4  -0.785
//
// >>chng 06 nov 24, from -4.719 to -4.749, turn on Badnell RR
// >>chng 06 nov 29, from -4.749 to -4.685, Badnell DR turned on
monitor ionization Carbon 1  -4.685 
//
// >>chng 06 nov 29, from -1.091 to -1.173, Badnell DR turned on
monitor ionization Carbon 2  -1.173 
//
monitor ionization Carbon 3  -0.089 
//
// >>chng 06 nov 29, from -1.039 to -1.093, Badnell DR turned on
monitor ionization Carbon 4  -1.093 
//
// >>chng 06 nov 29, from -1.881 to -1.906, Badnell DR turned on
monitor ionization Carbon 5  -1.906
// 
// >>chng 06 jun 06, add these after query from Jane Charlton
// Mg0 column densities did vary greatly between c90 and c94 but
// no sims detected this 
// >>chng 06 nov 24, from -3.956 to -4.063, turn on Badnell RR
// >>chng 06 nov 29, from -4.063 to -3.557, Badnell DR turned on
// >>chng 08 oct 18, from -3.557 to -3.655, include Badnell UTA data
// >>chng 11 sep 15, from -3.655 to -3.511, Chianti for Fe moderate to high ions
monitor ionization Magnesium 1  -3.511
// 
// >>chng 06 nov 24, from -1.461 to -1.572, turn on Badnell RR
// >>chng 06 nov 29, from -1.572 to -1.618, Badnell DR turned on
// >>chng 08 oct 18, from -1.618 to -1.717, include Badnell UTA data
monitor ionization Magnesium 2  -1.717
// 
// >>chng 06 nov 29, from -0.075 to -0.116, Badnell DR turned on
monitor ionization Magnesium 3  -0.116 
// 
// >>chng 06 nov 29, from -0.926 to -0.714, Badnell DR turned on
monitor ionization Magnesium 4  -0.714 
// 
// >>chng 06 nov 29, from -2.227 to -1.813, Badnell DR turned on
monitor ionization Magnesium 5  -1.813 
// 
// >>chng 06 nov 29, from -3.830 to -3.487, Badnell DR turned on
monitor ionization Magnesium 6  -3.487
//
// >>chng 07 nov 29, from -5.209 to -5.307 update DR rates
// >>chng 08 oct 18, from -5.307 to -5.327, include Badnell UTA data
// >>chng 11 jul 12, from -5.327 to -6.259, update to head of branch, without new coll DR suppression
// >>chng 12 jul 01, from -6.259 to -5.563, update Badnell DR to 13-electron iso sequence
monitor ionization Silicon 1  -5.563
//
// >>chng 07 nov 29, from -1.193 to -1.316 update DR rates
monitor ionization Silicon 2  -1.316
//
// >>chng 08 oct 18, from -0.149 to -0.1742, include Badnell UTA data
monitor ionization Silicon 3  -0.1742
//
// >>chng 06 nov 29, from -0.863 to -0.778, Badnell DR turned on
// >>chng 08 oct 18, from -0.778 to -0.7361, include Badnell UTA data
monitor ionization Silicon 4  -0.7361
//
// >>chng 08 oct 18, from -1.064 to -1.018, include Badnell UTA data
monitor ionization Silicon 5  -1.018
//
// >>chng 06 feb 07, from -2.844 to -2.869, add exp to low-T DR 
// >>chng 08 sep 22, from -2.869 to -3.106, remove Ali et al. DR guess
monitor ionization Iron 2  -3.106
//
// >>chng 08 sep 22, from -0.827 to -1.017, remove Ali et al. DR guess
// >>chng 11 apr 22, from -1.017 to -0.9689, update Ar sequence Badnell DR rates
monitor ionization Iron 3  -0.9689
//
monitor ionization Iron 4  -0.178
//
// >>chng 06 nov 26, from -0.819 to -0.797, use Gu et al. UTA data
// >>chng 08 sep 22, from -0.797 to -0.6945, remove Ali et al. DR guess
// >>chng 11 apr 22, from -0.6945 to -0.7175, update Ar sequence Badnell DR rates
monitor ionization Iron 5  -0.7175
//
// >>chng 07 apr 30, from -1.511 to -1.485, log DR average, use mix S DR
// >>chng 07 nov 29, from -1.485 to -1.513, update DR rates
// >>chng 08 sep 22, from -1.513 to -1.457, remove Ali et al. DR guess
// >>chng 11 apr 22, from -1.457 to -1.502, update Ar sequence Badnell DR rates
monitor ionization Iron 6  -1.502
//
// >>chng 07 jan 20, from 5 to 8 (6.33) e2 bug
// >>chng 08 dec 08, from 8 to 5.833, upper limit -> equals (r2515)
// >>chng 08 dec 13, from 5.833 to 13.08, merging newsolvers branch
// >>chng 09 jan 08, from 13.08 to 14, minor changes in iter/zn, iterations, and zone that crept in over last month
// >>chng 09 jan 16, disabled this assert since this model has too few zones for it to be reliable
// assert itrzn 14 error 0.02
//
c igm_lalpha.in
c class igm 
c ========================================
c 
  
This example demonstrates the behavior of the code in the low-density limit. 
The ionizing source is the cosmic background at a redshift of z = 2. 
The cloud is assumed to be optically thin to ionizing radiation,
in keeping with the Gunn-Peterson test, so the double command is included,
and an iteration is performed to converge the optical depth scale. 
Continuum fluorescent excitation of lines is important because the cloud
is otically thin.