If I know plasma temperature and plasma electron density, how I can calculate its spectrum?
In general this can be very complicated but here's a few resources:
http://physics.nist.gov/PhysRefData/ASD/lines_form.html has a lot of atomic spectra and you can use the dynamic plots section to generate spectra given certain assumptions that may or may not apply to your use but are a useful and simple place to start.
For more complicated and detailed data, you can use ADAS http://open.adas.ac.uk/
This has lots of data to calculate emission from specific lines but you'll need to read through the documentation to use it.
This site has more lines than NIST but doesn't generate spectra; it is useful for identifying lines: http://www.pa.uky.edu/~peter/atomic/
Dear,
The boock ''Principles of Plasma Spectroscopy'' Cambridge University Press 1997 is very interesting.
May be also the followibg artIcle :
''Correction of self-absorption spectral line and ratios of transition probabilities for homogeneous and LTE plasma'' J.Q.S.RT, Volume 75, Issue 6, pp. 747-763 (2002), Hssaine Amamou, Andre Bois, Belkacem Ferhat, Roland Redon, Bruno Rossetto and Pascal Matheron.
As already pointed out by Dennis, the question you are posing is the fundamental aspect of plasma spectroscopy. It is a very complex problem and does not exist a simple answer.
Passing from the level distributions to spectra is not very complex, even if it presents some difficulties. Databases are available as the NIST. There also some tools as that developed in Ecole Central, Paris, by Christophe Laux (you can by a commercial version). But all available tools are not complete and need the level distribution.
Therefore the problem is to determine the level distribution from the quantity you are considering. It depends if you are in equilibrium or not, if you have atomic or molecular plasma and so on.
In the general case you need a kinetic model for your plasma to determine the composition and the distributions. It is an open research field, and you need to study papers and Books. I suggest you the Book by Griem Plasma Spectroscopy and Fundamental Aspects of Plasma Chemical Physics: Kinetics to enter in the argument.
The reactions so far seem to deal mostly with spectra of visible light (except perhaps the ADAS reference). In addition, there is a whole community of people who deal with hot, dense plasmas where the radiation of principal interest in in multi-keV x-rays. One buzzword here is "non-LTE": a useful resource here is e.g., FLYCHK. Google for it.
It depends on the line. There are different broadening mechanisms at play, such as natural, Doppler and Stark(ion plasma electon and ion) broadening. Depending on the line, this may be simple (e.g. for instance Doppler may be dominant, or even natural for high Z-lines). If you are looking for a general program, there are several good ones Note that thus far I only addressed the issue of computing the profile of a SINGLE line. If you are interested in a spectrum, consisting of possibly many lines, different elements and charge states, then the level propulations also matter, as stated by Gianpiero. Furthermore, if your plasma is dense enough, self-absorption can further broaden the line. So is your question a general one or are you looking for a specific line?
I forgot to mention that there are regular meetings and workshops among specialists in the field, who use a large number of test cases to compare code predictions, with significant convergence. See for instance http://plasma-gate.weizmann.ac.il/projects/slsp/slsp3/
As suggested, it is not an easy task to generate spectra from the known values of electron number density and plasma temperature. However, some basic concepts can be acquired from basic books such as : Plasma Spectroscopy by G.V. Maar, Spectrophysics by Ann Thorne, Plasma Spectroscopy by Griems.
The line strengths and identification data are available form NIST data base.
good luck
Good afternoon, Kimia Kim!
In the first approximation the emission spectrum of the plasma can be considered
as a blackbody radiation. The spectrum is calculated by Planck's law, (where T is the temperature of the plasma) + Emission spectra of ionized atoms.
For more information, you can view (http://www.inp.nsk.su/chairs/plasma/sk/fpl.ru.shtml).
Thank you for the question. D \ d
Добрый день Kimia Kim!
В первом приближении спектр излучения плазмы можно рассматривать
как излучение абсолютно чёрного тела. Спектр рассчитывается по закону М. Планка: (где Т-температура плазмы) + спектры эмиссии ионизованных атомов.
Более подробно об этом Вы можете посмотреть в (http://www.inp.nsk.su/chairs/plasma/sk/fpl.ru.shtml).
Спасибо за вопрос. Д\д
Please, be careful with a blackbody approximation. The plasma seldom is so optically thick for it to be valid. Usually the opposite is true. As the first approximation is best to use Saha spectrum feature available in NIST database as pointed out Dennis P Boyle.
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