CHIANTI

An Atomic Database for Spectroscopic Diagnostics of Astrophysical Plasmas.


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George Mason University (USA) - University of Michigan (USA) - University of Cambridge (UK) - NASA Goddard Space Flight Center (USA)


Database History

CHIANTI Database Version 10.1 and IDL version 10.2 released, June 2023

CHIANTI 10.1 contains updated ionization rates for 13 ions, and updated recombination rates for the phosphorus isoelectronic sequence. New electron collision and radiative datasets for eight ions in the nitrogen and oxygen isoelectronic sequences have been added, and energy level and wavelength data have been updated for seven other ions. Full details are given in Dere et al. (2023, ApJS).

The IDL software features a number of bug-fixes and improvements. The most significant is a change to how level populations are computed, which should lead to a speed increase in calculating synthetic spectra of around a factor five.

June 2022 - CHIANTI database version 10.0.2 released

This is a minor release, with a new directory 'em' added containing some emission measure distributions. There were no changes to the atomic data.

November 2020 - CHIANTI v. 10.0 released

CHIANTI 10 includes updated atomic data for most of the ions along the beryllium, carbon and magnesium isoelectronic sequences. The helium-like ion models have been upgraded to two-ion models to enable modeling of recombination and autoionization processes. A new model of Fe VII has been added that produces many lines in the extreme ultraviolet part of the spectrum, and a number of energy levels of the coronal iron ions Fe X-XII have been updated.

IDL software has been added to allow the suppression of dielectronic recombination rates to be modeled, leading to ionization fraction tables that are density sensitive. Updated rates for Si-like ions recombining to P-like ions have been added, along with improved recombination rates into neutral helium.

The paper describing CHIANTI 10 was published in The Astrophysical Journal.

September 2015 - CHIANTI v. 8.0 released

CHIANTI v. 8.0 includes several new entries and revises the atomic data for many ions. In particular, for ions of the He-like, Li-like, B-like, Ne-like and Na-like isoelectronic sequences, plus several important coronal iron and nickel ions.

In addition, the method for computing the differential emission measure has been changed.

Important note: for various reasons, it has been necessary to modify the format of the elvlc and splups files. The elvlc files have been restructured but retain the same name, while the splups files have been significantly revised and are now renamed as "scups" files. For both the updated elvlc and new scups files, an ascii fixed text width format has been retained. We have modified the CHIANTI software to read these new files, but all the main software is left unchanged.

The new database and IDL programs are incompatible with the previous CHIANTI versions and vice-versa.

August 2013 - CHIANTI v. 7.1.3 released

An error in the routine that calculates radiative recombination rates was discovered. This error mainly affected the ionization equilibrium of the neutral and first ionization stage. The new database file contains a corrected file of ionization equilibria chianti.ioneq as well as the previous version that has been renamed to chianti_v7.ioneq for those who are interested in the checking the differences.

May 2013 - CHIANTI v. 7.1.2 released

Version 7.1.1 is a bug-fix release. It corrects problems with the o_2.wgfa file that contains wavelengths, weighted-oscillator strengths and A-values.

April 2013 - CHIANTI v. 7.1.1 released

Version 7.1.1 is a bug-fix release. It corrects problems with the c_2.wgfa file that contains wavelengths, weighted-oscillator strengths and A-values.

October 2012 - CHIANTI v. 7.1 released!

The main feature of CHIANTI Version 7.1 is the inclusion of a large number of configurations to the atomic models of Fe VIII to XIV. These configurations give rise to a forest of spectral lines in the 50-170 A wavelength range that contribute significantly to the total radiative output of the Sun at those wavelengths. Also, they give rise to several strong lines that are currently neglected by spectral codes, and provide significant contributions to the SDO/AIA bandpasses centered at 94A and 131A. These data are calculated using the Flexible Atomic Code (FAC) under the distorted wave approximation. Additional data for a few more ions are included, that improve the available datasets for a few ions, and correct a few glitches for other ions at all wavelength ranges. New element abundance data sets are provided, and improved recombination rates are included and used to provide a new set of CHIANTI ionization equilibria (chianti.ioneq file).

October 2011 - CHIANTI v. 7 released!

We would like to announce the release of version 7.0 of the CHIANTI database for astrophysical spectroscopy. With Version 7.0, CHIANTI now includes data for several new ions as well as significant updates to many ions, including several key Fe species routinely observed by Hinode/EIS and SDO. Also, a completely new implementation of the CHIANTI software in the Python programming language has been developed and is freely available on the web -- ChiantiPy.

January 2010 - CHIANTI team receives award from the Royal Astronomical Society!

On January 8 2010 the CHIANTI team were awarded the Group Achievement Award for Geophysics by the Royal Astronomical Society (UK). The citation was:

"The Group Achievement Award for Geophysics is given to the CHIANTI consortium, the team of scientists who have developed the 'Atomic Database for Spectroscopic Diagnostics of Astrophysical Plasmas.' This is a powerful tool for scientists who use the dispersion of light by wavelength (spectroscopy) to measure the properties of astronomical objects, including their composition, temperature, density and magnetic field strength. The analysis requires detailed knowledge of a large range of atomic elements. The CHIANTI consortium's achievement is the establishment of a systematic, easy-to-use and publically available database to assist this process, with a huge impact on solar and stellar physics."

A full press release is available from the RAS website.

October 2009 - CHIANTI v. 6.0.1 released!

We found an error in the continuum routines: the routines assumed that in the DEM input the temperatures were specified at intervals of logT=0.1. An arbitrary interval is now allowed. With the previous versions of the continuum routines, if the user specified the CHIANTI.IONEQ ion balance the result would be a continuum that is a factor two too high since the DEM would be tabulated at 0.05 dex intervals whereas the continuum routines would be expecting 0.10 intervals.

Version 6.0.1 corrects this error. The error only affected calculations done using the CHIANTI.IONEQ ion balance, and it did not affect calculations done with earlier versions of the database.

The routines should now yield the same continuum as calculated in version 5.2 and earlier. CHIANTI 6 saw the first release of an ion balance file (chianti.ioneq) for which the temperature spacing was 0.05 dex (in log T) rather than the usual 0.10. A temperature spacing of 0.10 had been hardcoded in the continuum routines, and so the derived continuum when using the chianti.ioneq file became a factor 2 larger than it should have been. (Note that the 0.10 spacing was not hardcoded for emission line calculations and so these are unaffected.) This bug has been fixed, and the changes will be transparent if you use ch_ss, ch_synthetic and make_chianti_spec for generating synthetic spectra.

If you directly call the CHIANTI continuum routines (freefree, freebound, two_photon) please note that a new keyword has been introduced called EM_INT. If you are modelling an isothermal plasma, you should use EM_INT to specify the emission measure value. If you are modelling a plasma with a differential emission measure curve you should specify the DEM values through the keyword DEM_INT. Previously the user would have to specify emission measures by manually converting them to DEM values and then inputting them via DEM_INT.

An error was also corrected in the calculation of the correction factor to include ionization and recombination effects into level populations. Such error only affected results at very low densities, when collisional excitation becomes very small.

A few minor typos were also corrected in cr_7.wgfa, mn_8.wgfa, fe_18.cilvl and fe_18.reclvl files.

July 2009 - CHIANTI v. 6 released!

We would like to announce the release of the version 6.0 of the CHIANTI database for astrophysical spectroscopy. With Version 6, CHIANTI includes ionization and recombination coefficients for the calculation of ion fractions, as well as software to read and handle them. CHIANTI 6.0 also improves the calculation of He-like line intensities, and renews the data for the Be-like and F-like sequences and for the key ions Fe XVIII and Fe XX. Data for many other ions have been updated and new ions have been added to the database. Ion fraction datasets from recent calculations are also included. The main changes in the data consist of the renewal of the data of Fe XVIII and XX to improve the calculation of a large number of lines in the X-rays, n=3,4 configurations in the Be-like and F-like sequences to predict a large number of lines at UV and soft X-ray wavelengths.

July 2008 - CHIANTI v. 5.2.1 released!

The collisional data for Fe XIII were mistakenly taken from an older version of the database and were different from the Gupta & Tayal data we had selected. This affected the emissivities of a few Fe XIII lines. Version 5.2.1 corrects them.

April 2006 - Ne VI missing transition added

The radiative decay of level 2 to the ground level in Ne VI has been added to the ne_6.wgfa file. This change has no effect in solar coronal plasmas, but it makes a difference for lower density plasmas.

March 2006 - CHIANTI v. 5.2 released!

A few collisional transitions were mistakenly left out of the fe_17.splups file, that caused the emissivities of a few lines to be incorrectly calculated at densities larger than 10^12 cm^-3. Also, the collisional excitation rate for the 5-11 transition in O IV was also mistakenly left out, affecting the emissivity of this line at densities larger than 3x10^8 cm^-3. These transitions are now included in CHIANTI.

The CHIANTI continuum IDL routines have also been modified to include the keyword /keV that allows the calculation of the continuum emission photon/cm^2/s/sr/keV (or erg/cm^2/s/sr/keV)

September 2005 - CHIANTI v. 5.1 released!

CHIANTI V. 5.1 corrects for an error in the Fe dielectronic satellite lines in the 1.7-2.0 Angstrom range, and a few software bugs affecting isothermal calculations and the two-photon continuum.

August 2005 - CHIANTI v. 5 released!

We would like to announce the release of the version 5.0 of the CHIANTI database for astrophysical spectroscopy. With Version 5, CHIANTI includes ionization and recombination as mechanisms for populating excited levels, photoexcitation from any user-defined radiation field, software for taking into account non-Maxwellian velocity distributions, and new data for a large number of ions (both for new entries or for ions already in the database). Changes in the data consist of the inclusion of high-energy configurations of Fe XVII to XXIII to predict a large number of lines in the X-rays, n=3 configurations in the N-like and O-like sequences to predict a large number of lines at UV wavelengths, and new data for very important ions in the EUV wavelength range such as Fe IX, Fe XII and Fe XV. The software has been speeded considerably and a few more user-friendly features have been added.

Atomic Data Updates

The updates contained in Version 4.0 of CHIANTI involve ions emitting at all wavelength ranges. Updates by iso-electronic sequence are as follows:

Hydrogen sequence
He II, Ne X, Na XI, Mg XII, P XV, Cl XVII, K XIX

Helium sequence
He I, C V, N VI, O VII, Ne IX, Na X, Mg XI, Al XII, Si XIII, P XIV, S XV, Cl XVI, Ar XVII, K XVIII, Ca XIX, Fe XXV

Lithium sequence
Fe XXIV

Beryllium sequence
C III, O V, Ar XV, Fe XXIII

Boron sequence
C II, N III, O IV, Ne VI, S XII, Ar XIV, Fe XXII

Carbon sequence
O III, Ne V, S XI, Cl XII, Fe XXI

Nitrogen sequence
Mg VI, S X, Cl XI, Ar XII, Ca XIV, Fe XX I, Zn XXIV

Oxygen sequence
Ne III, Mg V, Al VI, Si VII, P VIII, S IX, Cl X, Al XI, K XII, Ca XIII, Ti XV, Cr XVII, Mn XVIII, Fe XIX, Co XX, Ni XXI, Zn XXIII

Fluorine sequence
Fe XVIII

Neon sequence
Ar IX, Fe XVII

Magnesium sequence
Al II, Fe XV

Aluminum sequence
S IV, Ca VIII

Silicon sequence
Ca VII, Fe XIII

Phosphorus sequence
K V, Fe XII

Sulphur sequence
Cl II

Argon sequence
Fe IX

Potassium sequence
Fe VIII

Calcium sequence
Fe VII

CHIANTI IDL Procedures Updates

Software
Routines speeded up considerably
New software for photoexcitation from user-defined radiation fields
New software for non-Maxwellian velocity distributions

December 3, 2003 - CHIANTI v 4.2 released!

Version 4.2 corrects a few errors in the following files:
O II : o_2.splups
N VI : n_6.splups
C V : c_5.splups
S II : s_2.wgfa
Si II : si_2.wgfa
Ne III : ne_3.wgfa
Al XII : al_12.wgfa
Fe XIX : fe_19.wgfa, fe_19.splups
Fe XXIIId : fe_23d.elvlc, fe_23d.wgfa
and improves the wavelengths and energy level values for the following ions:
Ca XVIIId : ca_18d.wgfa
Fe XX : fe_20.wgfa, fe_20.elvlc
Fe XXIId : fe_22d.wgfa
Fe XXIVd : fe_24d.wgfa
Fe XXIV : fe_24.elvlc, fe_24.wgfa
Fe XXVd : fe_25d.wgfa
New data for two innershell transitions for Fe XXIII have been inserted: they have been calculated using the Flexible Atomic Code developed by Dr. Ming-Feng Gu.

Moreover, collisional data for some missing transitions from metastable levels were inserted for the following ions: Ar IV, Fe VIII, N I, Ne VII, Ni XIII and Ni XVI.

Details for these changes have been inserted in the comments of each modified file.

The software was corrected for an error that affected all the satellite lines in the X-rays, a bug in the calculation of the freefree continuum, and a few minor bugs; many improvements were also added, mostly for Windows-compatibility.

August 8, 2003 - CHIANTI software v 4.1 made available

We have corrected a few minor bugs and added a few improvements. See the HISTORY file for details.

February 6, 2003 - CHIANTI v. 4.02 released!

Since the release of CHIANTI 4.0 we have discovered errors in the ionization equilibrium (.ioneq) files for the following ions:
1 - mazzotta_etal.ioneq, mazzotta_etal_ext.ioneq: Ar XII to Ar XIX

2 - arnaud_raymond.ioneq, arnaud_raymond_ext.ioneq: Fe VII

3 - shull_steenberg.ioneq, shull_steenberg_ext.ioneq: All Fe ions

Moreover, errors in the original papers were found for the ion fractions of Ca I and Fe I (Arnaud & Rothenflug 1985).

December 2, 2002 - CHIANTI v. 4.01 released!

Since the release of CHIANTI 4.0 we have discovered errors in two data files in CHIANTI:
1 - the "itoh.dat" file was corrupted

2 - the file "si_9.splups" was missing the 3-4 transition

The itoh.dat file is used in the calculation of the bremsstrahlung continuum radiation. The missing 3-4 transition in Si IX affected significantly the emissivities of only a few lines in the visible and of the 258.08 A and 227.36 A lines in the EUV. Corrected versions of both these files are now distributed in Version 4.01.

In order to improve backward-compatability, we also have included in Version 4.01 the ion fractions, element abundances and DEM files from Version 3 in the "version_3" subdirectories within the "ioneq/", "abund/" and "dem/" directories.

September 2002 - CHIANTI v. 4 released!

We would like to announce the release of the Version 4.0 of the CHIANTI database for astrophysical spectroscopy. With Version 4, CHIANTI includes proton excitation rates for most of the ions in the database. New ions have been inserted, expecially the first neutral species (H I, He I, N I), and data for many ions have been renewed. Two-photon continuum radiation has been included, along with a new code for calculating relativistic free-free continuum. A new feature of the CHIANTI database is the use of 9-point spline fitting to scaled effective collision strengths, that allows a more accurate representation of upsilons over large temperature range. We have completely rewritten the entire software and made it compatible with Windows NT and VMS. The new software is compatible with the previous versions of the database.


Atomic Data Updates

The updates contained in Version 4.0 of CHIANTI involve ions emitting at all wavelength ranges. Updates by iso-electronic sequence are as follows:

Updates by iso-electronic sequence are as follows:

Hydrogen sequence
H I

Helium sequence
He I

Lithium sequence
C IV, O VI

Beryllium sequence
O V, Al X, Si XI, S XIII, Ar XV, Ca XVII, Fe XXIII

Boron sequence
Al IX, Si X, S XII, Ar XIV, Ca XVI, Fe XXII

Carbon sequence
Ne V, Fe XXI
Nitrogen sequence
N I, O II, Mg VI, Al VII, Si VIII, P IX, S X, Ar XII, K XIII, Ca XIV, Ti XVI, Cr XVIII, Mn XIX, Fe XX, Co XXI, Ni XXII, Zn XXIV

Oxygen sequence
Ne III, S IX, Fe XIX, Ni XXI

Fluorine sequence
Fe XVIII

Magnesium sequence
Fe XV

Phosphorus sequence
S II, Ar IV, Fe XII

Scandium sequence
Fe VI



CHIANTI IDL Procedures Updates

Software
Completely rewritten
Compatible with Windows NT and VMS

Continuum
Two-photon continuum added
Free-free modified to include relativistic effects

effective collision strengths fit
9-point spline fit added, to better reproduce effective collision strengths

Dec 20, 2001 - CHIANTI v. 3.03 of the database and software made available

It has recently been pointed out that the CHIANTI (x+y+z)/w intensity ratio of O VII and Si XIII in the X-ray wavelength range were in disagreement with observations. Disagreements for O VII were moderate, those for Si XIII were significant. We have discovered a small mistake in the transition energies of transitions 1-5 and 1-6 in the o_7.splups and si_13.splups files which was the cause of these disagreements. For this reason, the o_7.splups and si_13.splups files have been corrected (CHIANTI version 3.03 of the database). We have also corrected a minor error in the 'freefree.pro' routine for the calculation of the free free continuum. (CHIANTI version 3.03 of the software).

Nov 19 2001 - CHIANTI v. 3.02 of the software made available

We have discovered an error in the calculation of the free-free continuum in the CHIANTI software package ('freefree.pro'). The error was associated with the mislabeling of the original data file for the gaunt factor. The effects of this error are significant only at high temperatures, where the freefree contribution is most important. The relevant procedures have been corrected and the whole software package has been released as v. 3.02.

Apr 30 2001 - CHIANTI v. 3.02 of the database made available

It has recently been pointed out that the intensities of a few O V lines predicted by the CHIANTI database are in disagreement with SOHO/SUMER observations on the Sun. The collision rates in the current (3.01) version of CHIANTI are from distorted wave calculations from Zhang & Sampson 1992. However, their rates for O V do not appear to agree well with the other members of the iso-electronic sequence. It has been found that collisional transition proabilities from Berrington et al. (1985) provide a better reproduction of the observations. For this reason, the o_5.splups in the latest version of the CHIANTI database (version 3.01) has been replaced with the Berrington et al. (1985) data. The tar files on our web sites have been updated, as Version 3.02. The only change from version 3.01 is the revised O V collisional data. Also the files in the SolarSoft package have been updated with the new data. Some tests have shown that changes in the emissivities of the O V lines in the EUV spectral range between 600 A and 800 A are moderate (within 10%), while the effects on the 1218/1371 line ratio are greater. Electron densities measured using the 1218/1371 line ratio are now much more in agreement with estimates from ratios of other ions.

28 November 2000 - new CHIANTI package within SolarSoft made available

We have reorganised and updated the whole CHIANTI package under SolarSoft: 
$SSW/packages/chianti/
Now: 
$SSW/packages/chianti/dbase/  contains the lite  version 3.01 of the CHIANTI database
$SSW/packages/chianti/doc/    contains various documentation including
                              new software notes

In particular,

$SSW/packages/chianti/doc/chianti_guide_1.0.ps

replaces the previous CDS software notes #33,37,50 (now obsolete). 


$SSW/packages/chianti/idl/   contains all the CHIANTI routines.

In particular, it contains the routines that  before could only be found in 
$SSW/soho/cds/idl/sci/data_anal/spec_syn

Also,

$SSW/packages/chianti/idl/extra/  contains some extra routines that Peter Young 
            contributed. These routines are described in the 
$SSW/packages/chianti/doc/cds_swnote_52.ps  document.

28 November 2000 - CHIANTI v. 3.01 of the procedures made available

We have updated some of the CHIANTI IDL routines. The main changes affect the way the continuum was calculated. Also, some minor bugs have been fixed. We have also reorganised the routines into subdirectories, so you will need to add to your IDL_STARTUP file (if not there already): 
 !PATH = '+/data/chianti_pro_v3.01:'+!PATH
 !PATH = EXPAND_PATH(!PATH)
The modified routines are: temperature_ratios, gofnt, setup_ion, conf2n, freebound,freefree,synthetic,synthetic_plot, density_ratios, read_ioneq, latex_wvl_dem, ascii_wvl_dem.

28 September 2000 - CHIANTI v. 3.01 made available

Since our announcement of the release of Version 3.0 of the CHIANTI database we have determined that there are errors in few of the files in that release. The errors include incorrect collisonal data for the He II 304 line and two-photon transitions that appear as spectral lines in some of the helium sequence ions. These files have been corrected and a new version, Version 3.01, is now available. If you have downloaded Version 3.0, we highly recommend that you replace it with Version 3.01. We regret any inconvenience this has caused you.

1 September 2000 - release of the new CHIANTI v. 3.0

We would like to announce the release of Version 3.0 of the CHIANTI database for astrophysical spectroscopy. This release extends CHIANTI into the X-ray wavelength region between 1 and 50 Angstroms. This has largely been accomplished by including the necessary atomic data for the hydrogen- and helium-like isoelectronic sequences and their satellites. In addition, the atomic data for a number of other ions have also been updated and revised. In order to include the satellite lines, it has been necessary to modify the IDL procedures that calculate spectral lines intensities. Consequently, it is necessary to download both the new data files and the new set of IDL procedures. The additions to the database are described in a paper `CHIANTI - an atomic database for emission lines, IV - Extension to X-ray Wavelengths' by K.P. Dere, E. Landi, P.R. Young, and G. Del Zanna, and has been submitted to the Astrophysical Journal Supplement Series.


Atomic Data Updates

The updates contained in Version 3.0 of CHIANTI are primarily concerned with extending its coverage to include the 1 - 50 Å wavelength region. The inclusion of emission lines from the hydrogen and helium isoelectronic sequences and their satellite line and improved models of highly ionized iron (Fe) ions are the principal ingredients for achieving this. Below, we list the newly included ions and the ions which have been modified for improved X-ray coverage.

Updates by iso-electronic sequence are as follows:

Hydrogen sequence
C VI, N VII, O VIII, Ne X, Na XI, Mg XII, Al XIII, Si XIV, S XVI, Ar XVIII, Ca XX, Fe XXVI, Ni XXVIII

Helium sequence (including satellites to the hydrogen-like lines)
C V, N VI, O VII, Ne IX, Na X, Mg XI, Al XII, Si XIII, S XV, Ar XVII, Ca XIX, Fe XXV, Ni XXVII

Lithium sequence satellites to the helium-like lines
C IV, N V, O VI, Ne VIII, Na IX, Mg X, Al XI, Si XII, S XIV, Ar XVI, Ca XVIII, Fe XXIV, Ni XXVI

Lithium sequence with inner-shell excitations
O VI, Ne VIII, Mg X, Al XI, Si XII, S XIV, Ar XVI, Ca XVIII, Fe XXIV, Ni XXV

Other dielectronic satellites to helium-lines
Fe XXI, Fe XXII, Fe XXIII

Beryllium sequence
Mg IX: R-matrix collision strengths included

Nitrogen sequence
Fe XX: R-matrix collision strengths withing the ground configuration

Neon sequence
Fe XVII: n=4 levels now included
Ni XIX: n=4 levels now included

Silicon sequence
S III
Fe XIII: R-matrix collision strengths included for some transitions

Sulphur sequence
Fe XI: R-matrix collision strengths included for some transitions

Chlorine sequence
Fe X: n=4 and n=5 levels included



CHIANTI IDL Procedures Updates

Procedures for calculating the continuum due to free-free (bremsstrahlung) and free-bound (radiative recombination) are now included. Their names are 'FREEFREE' and 'FREEBOUND', respectively. A procedure ('RAD_LOSS') calculates the total radiative loss rate as a function of temperature for specified set of abundances and/or ionization equilibria.

One nice feature initiated in Version 1.03 is that by typing the name of a procedure, while in IDL, it's correct calling sequence is returned.

We have also renamed some of the utility procedures ('ch_...') so that they don't conflict with IDL procedures distributed with the Solar Soft-Tree.

12 April 1999 - CHIANTI version 2 now available

Version 2.0 is now available for downloading at the following site:

http://www.chiantidatabase.org/

Version 2.0 adds atomic data for many of the so called minor ions, such as fluorine and potassium, not included in the first version. Because the astrophysical abundances of these elements are relatively low, only the strongest lines of these elements are observed. The addition of the minor ions is an important step in our goal to understand astrophsical spectra in detail. In addition, Version 2.0 extends the beryllium-like sequence, updates some of the data in Version 1, and provides an IDL procedure to calculate the continuum.

1 March 1999 - CHIANTI Paper III published

Paper III of the CHIANTI series has been published in the Astronomy & Astrophysics Supplement Series (Vol. 135, 339-346). This paper describes the updates that will be contained in Version 2 of the database.

We are still performing checks on the new data and routines contained in Version 2, but it will be ready for release soon.

20 Feb 1998 - REVISED Ca XVI FILE

The ca_16.splups file has been revised. You can download this new file below:

ca_16.splups.

18 June 1997 - CHIANTI PAPER II SUBMITTED

The second paper in the CHIANTI series has been submitted to Astronomy and Astrophysics, and in it we perform a detailed comparison of theoretical line intensities predicted from the CHIANTI atomic data with the observed intensities contained in the SERTS-89 active region spectrum. The paper has been later published in Astronomy & Astrophysics 329, 291-314.

29 April 1997 - VERSION 1.01 RELEASED

We have made the following changes to the CHIANTI data base that is now released as version 1.01. Because of the number of changes and correction, we suggest that the complete database should be downloaded following the standard procedures in the README file. When the version 1.01 tar file is extracted, if will simply overwrite the existing files. There is no need to remove the version 1.0 files. Alternately, you could extract it into a new directory, make sure that your procedures work and then delete the old version.

Changes/corrections to the database are:

1. Fe X
The wavelength of transition 1-5 was corrected to 256.239 from 256.197
2. Beryllium sequence
3. Boron sequence
4. Fe XX
The wavelengths and gf and A values are now those from the NIST database. In particular, some of the strong lines in the EUVE short wave spectra are better matched with these data. Thanks to Rolf Mewe for pointing this out.
5. Differential emission measures
In the first release of CHIANTI, the differential emission measures were defined such that:

Intensity = Integral ( G(T) DEM(T) dlnT )

The advantage of this definition was that it was possible to compare to isothermal emission measures in a fairly direct fashion. However, the more standard definition is:

Intensity = Integral ( G(T) DEM(T) dT )

and we have decided to revert to this latter definition. Accordingly, all the of sample differential emission measures in !xuvtop/dem have been converted to this definition and the IDL procedures have been changed to perform the standard integration.

6. Ionization equilibria
The ionization equilibria Arnaud and Raymond (1992) for iron are also now included in the file 'arnaud_raymond.ioneq' in the standard directory. The ionization equilibria for all other ions are also included in this file but the values are taken from Arnaud and Rothenflug (1985). Thanks to Jeremy Drake for help in producing this file.
7. IDL procedures
A procedure isothermal.pro, written by Jeff Newmark (GSFC) is now included in our distribution of CHIANTI IDL procedures. It allows the calculation of the emitted spectrum at a specified temperature or at several specified temperatures. The density at each temperature can also be specified.
Because of the change in the treatment of differential emission measure files, it is also necessary to download the latest compressed tar file of the CHIANTI IDL procedures: CHIANTI_1.02_pro.tar.Z
The most conventient way to download these files is to go to our web site: http://www.chiantidatabase.org/
Please let us know of any problems or difficulties. Also, we believe that CHIANTI can now be run on VMS machines but needs to be tested. CHIANTI can also be easily adapted to run on Windows machines (Joan Schmelz, U. Memphis, has already demonstrated this) and we hope to have this incorporated into the next release.
8. CHIANTI and the Solar Software Library
CHIANTI is now included as part of the Solar Software Library. The CHIANTI consortium maintains a set of data files and IDL procedures on the web. We consider these to be the 'official' CHIANTI files. The Solar Software Library obtains copies of these files. The data files should be identical. There are small but significant modifications to the IDL procedures. These modifications mostly involve the use of IDL system variables by the CHIANTI IDL procedures and the use of Unix system variables by the Solar Software Library versions of these programs.

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