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Generalised collisional-radiative modelling for Silicon and beyond. Alessandra Giunta. Introduction and motivation. - PowerPoint PPT Presentation
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06-10-11ADAS workshop, Auburn
University 1
Generalised collisional-radiative modellingfor Silicon and beyond
Alessandra Giunta
06-10-11ADAS workshop, Auburn
University 2
Introduction and motivation
In both the astrophysics and fusion domains, various studies confirm that the use of zero-density population model and truncation of the population structure at a set of low levels (even if accurate data are available for them) can lead to mis-interpretation in comparing measurements and theory.
The application to all densities and the distinguishing of metastable states, oriented to dynamic conditions, place the issue in the environment of Generalised Collisional-Radiative (GCR) model (Summers et al. 2006).
ADAS population modelling, at its highest precision, has been applied to the ions of the elements from Hydrogen up to Neon.
New analysis in the lower temperature solar chromosphere and transition region (e.g. need of Si1+) and developments in the fusion context (e.g. ITER) require the extension of the range of species up to Argon and possibly beyond.
06-10-11ADAS workshop, Auburn
University 3
GCR ionisation and recombination coefficients
The GCR ionisation and recombination coefficients are supplied within ADAS by the adf11 data files and are needed to provide the fractional abundances.
Main date mnemonic within ADAS
Elements Sources Comments
85 He,C,N,O,Ne,Na,Mg,Al,Si,S,Ar,Ca,Fe,Ni
Arnaud & Rothenflug (1985)
scaled in Ne
-No full GCR-No metastables-Finite density effects
89from H to Ne,
Al,Si,S,Cl,Ar,Cr,Fe,Ni,Cu,Ge,Kr,Mo,Xe
EmpiricalVan Maanen (1985)
-No full GCR-No metastables-Less accurate density correction
96
H,He,C,N,O,NeSi
Na,Mg,Al,P,S,Cl,Ar
Full GCRSummers et al.
(2006)
-Full GCR-Metastables-Finite density effects
Black: in the databaseRed: new doneBlue: new in progress
06-10-11ADAS workshop, Auburn
University 4
Silicon GCR work scheme
STEP 1
STEP 2
STEP 5
STEP4
STEP 3
Ionisation rates
Specific ion files
Supplemented specific ion files
Projection data
Fractional abundances
adf07
adf04
adf04 +
S & R lines
adf17
adf11
06-10-11ADAS workshop, Auburn
University 5
STEP 1 – Ionisation rates
adf32
adf23adf07
ADAS8#2
adf56
promotion rulesdataset
specific driverfrom promotion
rules
CADW ionisationcross-sectioncalculations
direct + excitation/autoionisationcross-sectiondataset
total ground stateionisation coefficients(ground to ground andmetastable resolved)
06-10-11ADAS workshop, Auburn
University 6
STEP 1 – Ionisation rates
Metastable resolved adf07
CADW calculations provide ground to ground ionisation rates.
The need of ionisation resolved into ground and metastable initial and final parents has been addressed using the semi-empirical formula of Burgess & Chidichimo (1983), which has been adjusted to the CADW calculations.
Automation is important
06-10-11ADAS workshop, Auburn
University 7
STEP 2 – Specific ion files
Revised adf04 for light elements
Si0+
Si1+
Si2+
Si3+
Si4+
Si5+
Si6+
Si7+
Si8+
Si9+
Si10+
Si11+
Si12+
Si13+
Cowan calculations
Dufton & Kingston (1991)
Griffin et al. (1990)
Liang et al. (2009)
Liang et al. (2009)
Witthoeft et al. (2007)
Bhatia & Landi (2003)
Bhatia & Landi (2003)
Bhatia & Doschek (1993)
Liang et al. (2009)
Bhatia & Landi (2007)
Zhang et al. (1990)
Whiteford et al. (2005)
Sampson et al. (1983)
Details for Silicon
06-10-11ADAS workshop, Auburn
University 8
STEP 3 – Supplemented specific ion files
adf04
adf09
adf07 ADAS807
S lines
adf08_adas807
adf18_a09_a04
ADAS211
ADAS212
RR lines
adf08
RR+DR lines
specificion dataset
ionisation rate
coefficientdataset
state selectivedielectronic
dataset
integratedmappinggenerator
radiative recombinationmapping dataset
dielectronic recombinationmapping dataset
state selectiverecombination dataset
(for archiving)
full GCR adf04
adf04 with S lines
adf04 with RR lines
06-10-11ADAS workshop, Auburn
University 9
STEP 4 – Projection data
adf07
adf25
adf17
ADAS407adf04
driver file for bundle-n calculation
specific iondataset
resolved ionisationrate coefficientdataset
bundle-n populationcalculation
cross-reference driver file for DR data and ls-breakdown auto-ionisation rate
adf18/a09_p204
ADAS204projection matrix
06-10-11ADAS workshop, Auburn
University 10
STEP 4 – Projection data
Cross-reference driver files adf18/a09_p204
oic
adf27
ADAS701
ADAS704 Supplementary Auger break-up
DR data
AUTO-STRUCTURE
driver file containing the configurations
post-processor
06-10-11ADAS workshop, Auburn
University 11
STEP 5 – Fractional abundances
adf11
ADAS208
projection matrix
adf18/a09_p204
ADAS404
full GCR adf04
adf10 fragment
ADAS403
adf10 iso-electronic
adf17
cross-reference driver file
low-level resolved population model
initial tabulation of GCR coefficients at z-scaled electron temperature and density
iso-electronic master file containing GCR metastable resolved coefficients
final stage to stage and
metastable resolved GCR
coefficients
ADAS405fractional
abundances
06-10-11ADAS workshop, Auburn
University 12
Results for Silicon – ionisation rates
Comparison with Dere (2007) – This is a zero density direct coefficient
comparison from the ground state, using the underlying CADW adf07.
CADW
Dere
06-10-11ADAS workshop, Auburn
University 13
Results for Silicon – recombination ratesComparison with RR+DR of Badnell (2006) - The GCR recombination
coefficients are compared with the zero density RR+DR rates of Badnell (2006). The
lowest densities used in the ratios are 103 cm
-3 for Si
+2→Si
+1 and 10
7 cm
-3 for Si
+7→Si
+6.
GCR
Badnell
06-10-11ADAS workshop, Auburn
University 14
Results for Silicon – fractional abundances
Comparison with Bryans et al. (2009) - The finite density
effects are more evident for low ionisation stages where the
peaks move to lower electron temperatures.
GCR (at N
e=108 cm-3)
Bryans
06-10-11ADAS workshop, Auburn
University 15
Beyond Silicon
Needs: ▪ Reconstructing the emission and interpreting the behaviour of elements
heavier than Ne and even Si is essential in both astrophysics (e.g. Mg, S, Fe) and fusion (e.g. Ar).
Issues: ▪ Which resolution is appropriate.
▪ Continued update of data sources in response to improved calculations (excitation, ionisation, RR, DR).
▪ Automation and precision are both essential at this stage.
06-10-11ADAS workshop, Auburn
University 16
Issues ▪ Resolution GCR model is implemented in ADAS as ls resolution but: - moving to medium and heavy species and more highly ionised ions ic
resolution becomes appropriate - in finite plasma, going to higher quantum shells, terms of the same nl-shells
move into relative statistical proportions, so ca resolution is adequate
- finally l-subshells of the same n-shell move into relative statistical populations and bn resolution becomes suitable.
* the model exists
◊ the model almost exists
06-10-11ADAS workshop, Auburn
University 17
Issues
▪ Increasing the baseline An ADAS requirement is that a baseline collisional-radiative capability is available for any elements: - raising the quality of the baseline is systematically in progress - currently a new AUTOSTRUCTURE based distorted wave excitation upgrade is in progress, with undergoing and validation checks. This will strengthen particularly excitation data from the ground and metastable levels of ions. A later upgrade will extend the distorted wave data to all transitions in the adf04 data set with R-matrix used for transitions in the ground complex. These are general baseline lifting developments and are distinct from very detailed individual ion studies.
▪ Automation - In the GCR computation procedure a number of steps were performed as ad
hoc hand manipulation (e.g. metastable fractionation). - An objective is to set up a basis for implementing all of the steps automatically
without losing the underlying precision (in progress).
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