Lecture 9: CHIANTI demonstration

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Lecture 9CHIANTI demonstration

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CHIANTI in brief

• Various web sites
• http//wwwsolar.nrl.navy.mil/chianti.html
• http//www.damtp.cam.ac.uk/user/astro/chianti/
• http//www.arcetri.astro.it/science/chianti/chiant
  i.html
• http//www.scs.gmu.edu/kdere/chianti.html
• http//www.chianti.rl.ac.uk/
• http//www.mssl.ucl.ac.uk/www_solar/chianti/
• (the last link doesnt seem to work now...)

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CHIANTI summary

• CHIANTI is a set of critically evaluated
  up-to-date atomic data with software packages
  written in IDL allowing users to get spectra and
  parameters useful for calculating conditions in
  astrophysical (especially solar) plasmas.
• Various releases over the years we are now on
  version 5.2.
• It is free! They only ask you to acknowledge
  CHIANTI in your publications.

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CHIANTI web site home page
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CHIANTI references
CHIANTI User guides
Get html or pdf versions from the web site. The
original atomic data are in Direct access.

• It is worth looking at the first and at least the
  last of these papers
• Dere et al. (1997), AAS, 125, 149
• Landi et al. (1999), AAS, 135, 339
• Dere et al. (2001), ApJS, 134, 331
• Young et al. (2003), ApJS, 144, 135
• Landi et al. (2006), ApJS, 162, 261

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CHIANTI help

• For information or help with problems, contact
• chianti_help_at_halcyon.nrl.navy.mil
• For information via an e-mail list, send an
  e-mail message to landi_at_poppeo.nrl.navy.mil
• CHIANTI hold periodic meetings to update data and
  software. The chief players at present are Giulio
  DelZanna, Enrico Landi, Peter Young, but others
  still very active.

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CHIANTI Getting started

• We will try a few programs that will be useful in
  spectral synthesis and atomic parameters relevant
  for the solar atmosphere.
• To get started, you need to load chianti in your
  SolarSoft tree.
• You may need to do the following
• sswidl
• IDLgt ssw_path,/chianti

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How the SolarSoft CHIANTI package is arranged

• On my Windows laptop, I have CHIANTI database on
• C\ssw\packages\chianti\dbase\
• For example in the folder ioneq, there are all
  the various ionization equilibrium calculations
  (e.g. Mazzotta et al. 1998 mazzotta_etal_9.ioneq
  ).
• In the folder abundance, there are various
  solar element abundance sets, e.g.
  sun_coronal.abund Feldman et al. (2002).
• All the files are ASCII-readable.

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CHIANTI calculating a spectrum

• Using ch_ss, the spectral synthesis program,
  calculate the EUV (extreme ultraviolet) spectrum
  of the solar corona between 160 and 200 Å.
• Assume an electron density Ne 1010 cm-3
  (active region-type density).
• Use the ionization fractions of Mazzotta et al.
  (1998), but extended (mazzotta_etal_9.ion).
• Use a DEM (differential emission measure) for an
  active region.
• Assume no photo-excitation but include proton
  excitation.

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CHIANTI synthesizing the spectrum

• Second stage of ch_ss synthesizing the spectrum
  that you calculated in the first part.
• Here, assume the same range.
• Use a spectrometer that has a resolution (FWHM)
  of 0.05 Å.
• This should be less than the thermal Doppler
  width of (e.g.) Fe IX lines in this region
  (0.02 Å).
• Bin width (number of points defining each lines
  profile) 0.01 Å.
• Save the spectrum or create a ps file.

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Synthesized spectrum for this DEM.

• What are the transitions for the strong lines at
  171 Å, 174.5 Å, 180.4 Å, 195.1 Å?
• Are they resonance lines?
• Now repeat the spectral synthesis for Ne 1016
  cm-3 (suitable for a laser plasma in the
  laboratory).

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Comparing the 2 spectra
Ne 107 cm-3
Ne 1010 cm-3
Several additional lines. Why the differences?
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Level populations of ground configurations

• Quit from ch_ss and put in command line
• IDLgt plot_populations,'fe_10',1.e6,5
• i.e. the populations of the lowest 5 levels of Fe
  X for T 1 MK.

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G(T) functions
Relative fluxes for 8 Fe X lines listed below.
The fluxes are relative to the strongest line at
174.5310 Å
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Plotting ionization fractions
Use command IDLgt plot_ioneq,'fe to get this plot
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How the SolarSoft CHIANTI package is arranged

• On my Windows laptop, I have CHIANTI database on
• C\ssw\packages\chianti\dbase\
• For example in the folder ioneq, there are all
  the various ionization equilibrium calculations
  (e.g. Mazzotta et al. 1998 mazzotta_etal_9.ioneq
  ).
• In the folder abundance, there are various
  solar element abundance sets, e.g.
  sun_coronal.abund Feldman et al. (2002).
• All the files are ASCII-readable.

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Other CHIANTI files

• Under the dbase folder, you can find all the
  atomic data for each element used in CHIANTI.
• For example, go to s (for S sulphur) to find
  folder containing data for each ion s_16 S XVI
  (should be S15!).
• Wavelengths, transitions etc. are in s_16.wgfa,
  Upsilon (excitation coefficients) in s_16.splups
  etc.