J/A+A/626/A123ivo://CDS.VizieR/J/A+A/626/A123doi:10.26093/cds/vizier.36260123CDSDufresne R.P.Del Zanna G.2019-07-26T09:58:00Z2019-06-21T08:48:47ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.fratomic-physicsThe aim of this work is to improve the modelling of ion populations in higher density, lower temperature astrophysical plasmas, of the type commonly found in lower solar and stellar atmospheres. Ion population models for these regions frequently employ the coronal approximation, which assumes conditions more suitable to the upper solar atmosphere, where high temperatures and lower densities prevail. The assumed conditions include all ions being in the ground state and steady-state equilibrium, where there is sufficient time for ionisation and recombination to take place. Using the coronal approximation for modelling the solar transition region gives theoretical lines intensities for the Li-like and Na-like isoelectronic sequences which are often factors of two to five times lower than observed. The works of Burgess & Summers (1969ApJ...157.1007B) and Nussbaumer & Storey (1975A&A....44..321N) show the important part ions in excited levels play when included in the modelling. As density increases metastable levels become populated and ionisation rates increase, whereas dielectronic recombination through highly excited levels is suppressed. Photo-ionisation is also shown by Nussbaumer & Storey to have an effect on the charge-state distribution of carbon in these regions. Their models, however, use approximations for the atomic rates to determine the ion balance. Presented here is the first stage in rates to determine the ion balance. Presented here is the first stage in updating these earlier models of carbon by using rates from up-to-date atomic calculations and more recent photo-ionising radiances. Where atomic rates were not readily available, in the case of electron impact direct ionisation and excitation-auto-ionisation, new calculations were made using the Flexible Atomic Code and Autostructure, and compared to theoretical and experimental studies. The effects each atomic process has on the ion populations as density changes is illustrated, and final results from the modelling are compared to the earlier works. Lastly, the new results for ion populations were used to predict line intensities for the solar transition region in the quiet Sun. In comparison to coronal approximation modelling the new results show significantly improved agreement with observations.2019A&A...626A.123Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/626/A123CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/626/A123https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/626/A123http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/626/A123https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/626/A123https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/626/A123http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/626/A123GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/626/A123/levelsEnergy level index and their configurationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintZAtomic number of elementphys.atmol.elementintNNumber of electrons in ionmeta.numberintLevelEnergy level indexmeta.code;spect.index;phys.atmol.levelintConfigElectron configuration of levelphys.atmol.configurationcharSSpin angular momentum of levelphys.angMomentum;phys.atmol.levelintLOrbital angular momentum of levelphys.angMomentum;phys.atmol.levelint2JTotal angular momentum of level x2phys.angMomentum;phys.atmol.levelintdELevel energy relative to ground level of ioneVphys.energy;phys.atmol.leveldoubleJ/A+A/626/A123/tempsTemperatures for rate coefficientsTemp6Temperature 6Kphys.temperaturedoubleTemp7Temperature 7Kphys.temperaturedoubleTemp3Temperature 3Kphys.temperaturedoubleTemp4Temperature 4Kphys.temperaturedoubleTemp5Temperature 5Kphys.temperaturedoubleTemp8Temperature 8Kphys.temperaturedoubleTemp9Temperature 9Kphys.temperaturedoubleZAtomic number of elementphys.atmol.elementintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNNumber of electrons in ion before impactmeta.numberintTemp1Temperature 1Kphys.temperaturedoubleTemp2Temperature 2Kphys.temperaturedoubleTemp10Temperature 10Kphys.temperaturedoubleTemp11Temperature 11Kphys.temperaturedoubleTemp12Temperature 12Kphys.temperaturedoubleTemp13Temperature 13Kphys.temperaturedoubleJ/A+A/626/A123/di_ratesDI Rate coefficientsT3Display the Temp3 temperature valuemeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintZAtomic number of elementphys.atmol.elementintNNumber of electrons in ion before impactmeta.numberintilevelInitial level of ion before impactphys.energy;phys.atmol.levelintflevelFinal level after impact of ionised ionphys.energy;phys.atmol.levelintIPThreshold energy for processeVinstr.sensitivitydoubleT1Display the Temp1 temperature valuemeta.ref.urlcharRate1Rate coefficient at Temp1(Z,N)cm**3.s**-1phys.atmolcharT2Display the Temp2 temperature valuemeta.ref.urlcharRate2Rate coefficient at Temp2(Z,N)cm**3.s**-1phys.atmolcharRate3Rate coefficient at Temp3(Z,N)cm**3.s**-1phys.atmolcharT4Display the Temp4 temperature valuemeta.ref.urlcharRate4Rate coefficient at Temp4(Z,N)cm**3.s**-1phys.atmolcharT5Display the Temp5 temperature valuemeta.ref.urlcharRate5Rate coefficient at Temp5(Z,N)cm**3.s**-1phys.atmolcharT6Display the Temp6 temperature valuemeta.ref.urlcharRate6Rate coefficient at Temp6(Z,N)cm**3.s**-1phys.atmolcharT7Display the Temp7 temperature valuemeta.ref.urlcharRate7Rate coefficient at Temp7(Z,N)cm**3.s**-1phys.atmolcharT8Display the Temp8 temperature valuemeta.ref.urlcharRate8Rate coefficient at Temp8(Z,N)cm**3.s**-1phys.atmolcharT9Display the Temp9 temperature valuemeta.ref.urlcharRate9Rate coefficient at Temp9(Z,N)cm**3.s**-1phys.atmolcharT10Display the Temp10 temperature valuemeta.ref.urlcharRate10Rate coefficient at Temp10(Z,N)cm**3.s**-1phys.atmolcharT11Display the Temp11 temperature valuemeta.ref.urlcharRate11Rate coefficient at Temp11(Z,N)cm**3.s**-1phys.atmolcharT12Display the Temp12 temperature valuemeta.ref.urlcharRate12Rate coefficient at Temp12(Z,N)cm**3.s**-1phys.atmolcharT13Display the Temp1 temperature valuemeta.ref.urlcharRate13Rate coefficient at Temp13(Z,N)cm**3.s**-1phys.atmolcharJ/A+A/626/A123/ea_ratesEA Rate coefficientsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintZAtomic number of elementphys.atmol.elementintNNumber of electrons in ionmeta.numberintilevelInitial level of ion before impactphys.energy;phys.atmol.levelintflevelFinal level after impact of ionised ionphys.energy;phys.atmol.levelintIPThreshold energy for processeVinstr.sensitivitydoubleT1Display the Temp1 temperature valuemeta.ref.urlcharRate1Rate coefficient at Temp1(Z,N)cm**3.s**-1phys.atmolcharT2Display the Temp2 temperature valuemeta.ref.urlcharRate2Rate coefficient at Temp2(Z,N)cm**3.s**-1phys.atmolcharT3Display the Temp3 temperature valuemeta.ref.urlcharRate3Rate coefficient at Temp3(Z,N)cm**3.s**-1phys.atmolcharT4Display the Temp4 temperature valuemeta.ref.urlcharRate4Rate coefficient at Temp4(Z,N)cm**3.s**-1phys.atmolcharT5Display the Temp5 temperature valuemeta.ref.urlcharRate5Rate coefficient at Temp5(Z,N)cm**3.s**-1phys.atmolcharT6Display the Temp6 temperature valuemeta.ref.urlcharRate6Rate coefficient at Temp6(Z,N)cm**3.s**-1phys.atmolcharT7Display the Temp7 temperature valuemeta.ref.urlcharRate7Rate coefficient at Temp7(Z,N)cm**3.s**-1phys.atmolcharT8Display the Temp8 temperature valuemeta.ref.urlcharRate8Rate coefficient at Temp8(Z,N)cm**3.s**-1phys.atmolcharT9Display the Temp9 temperature valuemeta.ref.urlcharRate9Rate coefficient at Temp9(Z,N)cm**3.s**-1phys.atmolcharT10Display the Temp10 temperature valuemeta.ref.urlcharRate10Rate coefficient at Temp10(Z,N)cm**3.s**-1phys.atmolcharT11Display the Temp11 temperature valuemeta.ref.urlcharRate11Rate coefficient at Temp11(Z,N)cm**3.s**-1phys.atmolcharT12Display the Temp12 temperature valuemeta.ref.urlcharRate12Rate coefficient at Temp12(Z,N)cm**3.s**-1phys.atmolcharT13Display the Temp1 temperature valuemeta.ref.urlcharRate13Rate coefficient at Temp13(Z,N)cm**3.s**-1phys.atmolchar