Special Issue "Spectral Line Shapes in Plasmas II"

A special issue of Atoms (ISSN 2218-2004).

Deadline for manuscript submissions: closed (31 January 2018)

Special Issue Editors

Guest Editor
Dr. Evgeny Stambulchik

Plasma Laboratory, Weizmann Institute of Science, Rehovot 7610001, Israel
Website | E-Mail
Phone: 972-8-9343610
Fax: 972-8-9343491
Interests: line-shape broadening in plasmas; Stark and Zeeman effects; polarization spectroscopy; non-LTE kinetics in plasmas
Guest Editor
Dr. Annette Calisti

Laboratoire PIIM, UMR7345, Aix-Marseille Université—CNRS, Centre Saint Jérôme Case 322, 13397 Marseille Cedex 20, France
E-Mail
Phone: +33(0)491282719
Guest Editor
Dr. Hyun-Kyung Chung

Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju Buk-gu Cheomdan-gwagiro 123, 61005, Korea
E-Mail
Phone: +82-10-7218-7285
Fax: +43 1 26007
Interests: atomic, molecular and plasma-surface interaction data for fusion applications; atomic processes in plasmas; non-LTE kinetics in plasmas; radiative properties of hot dense matter; plasma spectroscopy modeling
Guest Editor
Dr. Manuel Á. González Delgado

Departamento de Física Aplicada, Escuela Técnica Superior de Ingeniería Informática, Universidad de Valladolid, Paseo de Belén 15, 47011 Valladolid, Spain
E-Mail
Interests: atomic line shape calculation; plasma diagnostics; computer simulation; mLearning; biometrics

Special Issue Information

Dear Colleagues,

The Spectral Line Shapes in Plasma (SLSP) code comparison workshop series [1] has gained a steady momentum, with four meetings organized thus far—in 2012, 2013, 2015, and 2017. A large number of diverse problems have been analyzed, advancing understanding of the phenomena involved and increasing accuracy of the models. Doubtlessly, this has significantly aided in improving theoretical aspects of line-shape analysis—one of the most important tools for diagnostics of both laboratory and space plasma.

The first Special Issue of Atoms under this title was published in 2014 [2], covering selected topics from the first two workshops. With the hope of establishing tradition, we decided to arrange for the present Special Issue as a place for disseminating new results obtained in the course of the 3rd and 4th SLSP workshops. In addition, as it was also the case with the first “Spectral Line Shapes in Plasmas” Special Issue, we welcome contributions from the wider community working on diverse aspects of calculations of spectral line shapes in plasma.

[1] http://plasmagate.weizmann.ac.il/SLSP/

[2] http://www.mdpi.com/journal/atoms/special_issues/SpectralLineShapes

Dr. Evgeny Stambulchik
Dr. Annette Calisti
Dr. Hyun-Kyung Chung
Dr. Manuel Á. González Delgado
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Atoms is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 350 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • spectral line shapes
  • line broadening
  • Stark effect
  • Zeeman effect
  • code comparison

Published Papers (10 papers)

View options order results:
result details:
Displaying articles 1-10
Export citation of selected articles as:

Research

Jump to: Review

Open AccessFeature PaperArticle The Third and Fourth Workshops on Spectral Line Shapes in Plasma Code Comparison: Isolated Lines
Received: 18 March 2018 / Revised: 17 May 2018 / Accepted: 18 May 2018 / Published: 31 May 2018
PDF Full-text (439 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of the Spectral Line Shapes in Plasmas (SLSP) code comparison workshop is to compare different computational and analytical methods, in order to pinpoint sources of disagreements, infer limits of applicability, and assess accuracy. The present paper reviews a part of the
[...] Read more.
The purpose of the Spectral Line Shapes in Plasmas (SLSP) code comparison workshop is to compare different computational and analytical methods, in order to pinpoint sources of disagreements, infer limits of applicability, and assess accuracy. The present paper reviews a part of the results of the third (2015) and fourth (2017) workshops related to isolated lines. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Open AccessFeature PaperArticle H-β Line in a Corona Helium Plasma: A Multi-Code Line Shape Comparison
Received: 28 February 2018 / Revised: 14 May 2018 / Accepted: 15 May 2018 / Published: 23 May 2018
PDF Full-text (34974 KB) | HTML Full-text | XML Full-text
Abstract
Many spectroscopic diagnostics are routinely used as techniques to infer the plasma parameters from line emission spectra, but their accuracy depends on the numerical model or code used for the fitting process. However, the validation of a line shape code requires some steps:
[...] Read more.
Many spectroscopic diagnostics are routinely used as techniques to infer the plasma parameters from line emission spectra, but their accuracy depends on the numerical model or code used for the fitting process. However, the validation of a line shape code requires some steps: the comparison of the line shape code with other similar codes for some academic (simple) cases and then for more complex ones, the comparison of the fitting parameters obtained from the best fit of the experimental spectra with those obtained with other diagnostic techniques, and/or the comparison of the fitting parameters obtained by different codes to fit the same experimental data. Here we compare the profiles of the hydrogen Balmer β line in helium plasma computed by five codes for a selected set of plasma parameters and we report on the plasma parameters inferred by each of them from the fitting to a number of experimental spectra measured in a helium corona discharge where the pressure was in the range of 1–5 bars. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Open AccessFeature PaperArticle Revisiting the Stark Width and Shift of He II Pα
Received: 1 March 2018 / Revised: 28 March 2018 / Accepted: 18 April 2018 / Published: 24 April 2018
Cited by 1 | PDF Full-text (1554 KB) | HTML Full-text | XML Full-text
Abstract
We report experimental determination of plasma-induced Stark widths and shifts of the He II P α line and a comparison of the results with calculations performed by several computational approaches. The measurements were carried out in a small compressing plasma channel device, reaching
[...] Read more.
We report experimental determination of plasma-induced Stark widths and shifts of the He II P α line and a comparison of the results with calculations performed by several computational approaches. The measurements were carried out in a small compressing plasma channel device, reaching electron densities in excess of 10 18 cm 3 and temperatures of a few eV. The experimental data are in a good agreement with some previously published studies. However, the measured relation between the Stark shift and width could not be reproduced by either of the codes, and this disagreement is not yet resolved. This suggests the existence of an additional effect that is not accounted for in the present models and leads to a larger than expected Stark shift of the He II P α line. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Open AccessFeature PaperArticle Matrix Methods for Solving Hartree-Fock Equations in Atomic Structure Calculations and Line Broadening
Received: 7 March 2018 / Revised: 14 April 2018 / Accepted: 16 April 2018 / Published: 23 April 2018
PDF Full-text (398 KB) | HTML Full-text | XML Full-text
Abstract
Atomic structure of N-electron atoms is often determined by solving the Hartree-Fock equations, which are a set of integro-differential equations. The integral part of the Hartree-Fock equations treats electron exchange, but the Hartree-Fock equations are not often treated as an integro-differential equation. The
[...] Read more.
Atomic structure of N-electron atoms is often determined by solving the Hartree-Fock equations, which are a set of integro-differential equations. The integral part of the Hartree-Fock equations treats electron exchange, but the Hartree-Fock equations are not often treated as an integro-differential equation. The exchange term is often approximated as an inhomogeneous or an effective potential so that the Hartree-Fock equations become a set of ordinary differential equations (which can be solved using the usual shooting methods). Because the Hartree-Fock equations are an iterative-refinement method, the inhomogeneous term relies on the previous guess of the wavefunction. In addition, there are numerical complications associated with solving inhomogeneous differential equations. This work uses matrix methods to solve the Hartree-Fock equations as an integro-differential equation. It is well known that a derivative operator can be expressed as a matrix made of finite-difference coefficients; energy eigenvalues and eigenvectors can be obtained by using linear-algebra packages. The integral (exchange) part of the Hartree-Fock equation can be approximated as a sum and written as a matrix. The Hartree-Fock equations can be solved as a matrix that is the sum of the differential and integral matrices. We compare calculations using this method against experiment and standard atomic structure calculations. This matrix method can also be used to solve for free-electron wavefunctions, thus improving how the atoms and free electrons interact. This technique is important for spectral line broadening in two ways: it improves the atomic structure calculations, and it improves the motion of the plasma electrons that collide with the atom. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Open AccessFeature PaperArticle Broadening of the Neutral Helium 492 nm Line in a Corona Discharge: Code Comparisons and Data Fitting
Received: 28 February 2018 / Revised: 5 April 2018 / Accepted: 11 April 2018 / Published: 16 April 2018
Cited by 1 | PDF Full-text (36749 KB) | HTML Full-text | XML Full-text
Abstract
Passive plasma spectroscopy is a well-established non-intrusive diagnostic technique. Depending on the emitter and its environment which determine the dominant interactions and effects governing emission line shapes, passive spectroscopy allows the determination of electron densities, emitter and perturber temperatures, as well as other
[...] Read more.
Passive plasma spectroscopy is a well-established non-intrusive diagnostic technique. Depending on the emitter and its environment which determine the dominant interactions and effects governing emission line shapes, passive spectroscopy allows the determination of electron densities, emitter and perturber temperatures, as well as other quantities like relative abundances. However, using spectroscopy requires appropriate line shape codes retaining all the physical effects governing the emission line profiles. This is required for line shape code developers to continuously correct or improve them to increase their accuracy when applied for diagnostics. This is exactly the aim expected from code–code and code–data comparisons. In this context, the He i 492 nm line emitted in a helium corona discharge at room temperature represents an ideal case since its profile results from several broadening mechanisms: Stark, Doppler, resonance, and van der Waals. The importance of each broadening mechanism depends on the plasma parameters. Here the profiles of the He i 492 nm in a helium plasma computed by various codes are compared for a selected set of plasma parameters. In addition, preliminary results related to plasma parameter determination using an experimental spectrum from a helium corona discharge at atmospheric pressure, are presented. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Open AccessFeature PaperArticle Stark Broadening of Cr III Spectral Lines: DO White Dwarfs
Received: 7 March 2018 / Revised: 24 March 2018 / Accepted: 26 March 2018 / Published: 3 April 2018
PDF Full-text (305 KB) | HTML Full-text | XML Full-text
Abstract
Using the modified semiempirical method of Dimitrijević and Konjević, Stark widths have been calculated for six Cr III transitions, for an electron density of 1017 cm3 and for temperatures from 5000–80,000 K. Results have been used for the investigation of
[...] Read more.
Using the modified semiempirical method of Dimitrijević and Konjević, Stark widths have been calculated for six Cr III transitions, for an electron density of 10 17 cm 3 and for temperatures from 5000–80,000 K. Results have been used for the investigation of the influence of Stark broadening on spectral lines in cool DO white dwarf atmospheres. Calculated Stark widths will be implemented in the STARK-B database, which is also a part of the Virtual Atomic and Molecular Data Center (VAMDC). Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Open AccessFeature PaperArticle The Fourth Workshop on Lineshape Code Comparison: Line Merging
Received: 28 February 2018 / Revised: 26 March 2018 / Accepted: 29 March 2018 / Published: 31 March 2018
PDF Full-text (1940 KB) | HTML Full-text | XML Full-text
Abstract
For a given set of plasma parameters, along a single series (Lyman, Balmer, etc.) the lines with higher principal quantum number (n) lines get progressively wider, closer to each other, and start merging for a certain critical n. In the
[...] Read more.
For a given set of plasma parameters, along a single series (Lyman, Balmer, etc.) the lines with higher principal quantum number (n) lines get progressively wider, closer to each other, and start merging for a certain critical n. In the present work, four different codes (with further options) are used to calculate the entire Balmer series for moderate and high electron densities. Particular attention is paid to the relevant physics, such as the cutoff criteria, strong and penetrating electron collisions. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Open AccessFeature PaperArticle Influence of Helical Trajectories of Perturbers on Stark Line Shapes in Magnetized Plasmas
Received: 27 January 2018 / Revised: 23 February 2018 / Accepted: 23 February 2018 / Published: 13 March 2018
PDF Full-text (357 KB) | HTML Full-text | XML Full-text
Abstract
In plasmas subject to a strong magnetic field, the dynamical properties of the microfield are affected by the cyclotron motion, which can alter Stark-broadened lines. We illustrate this effect through calculations of the hydrogen Lyman α line in an ideal one-component plasma. A
[...] Read more.
In plasmas subject to a strong magnetic field, the dynamical properties of the microfield are affected by the cyclotron motion, which can alter Stark-broadened lines. We illustrate this effect through calculations of the hydrogen Lyman α line in an ideal one-component plasma. A focus is put on the central Zeeman component. It is shown that the atomic dipole autocorrelation function decreases more slowly if the cyclotron motion is retained. In the frequency domain, this denotes a reduction of the line broadening. A discussion based on numerical simulations and analytical estimates is done. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Open AccessFeature PaperArticle ZEST: A Fast Code for Simulating Zeeman-Stark Line-Shape Functions
Received: 31 January 2018 / Revised: 4 March 2018 / Accepted: 7 March 2018 / Published: 12 March 2018
Cited by 2 | PDF Full-text (882 KB) | HTML Full-text | XML Full-text
Abstract
We present the ZEST code, dedicated to the calculation of line shapes broadened by Zeeman and Stark effects. As concerns the Stark effect, the model is based on the Standard Lineshape Theory in which ions are treated in the quasi-static approximation, whereas the
[...] Read more.
We present the ZEST code, dedicated to the calculation of line shapes broadened by Zeeman and Stark effects. As concerns the Stark effect, the model is based on the Standard Lineshape Theory in which ions are treated in the quasi-static approximation, whereas the effects of electrons are represented by weak collisions in the framework of a binary collision relaxation theory. A static magnetic field may be taken into account in the radiator Hamiltonian in the dipole approximation, which leads to additional Zeeman splitting patterns. Ion dynamics effects are implemented using the fast Frequency-Fluctuation Model. For fast calculations, the static ion microfield distribution in the plasma is evaluated using analytic fits of Monte-Carlo simulations, which depend only on the ion-ion coupling parameter and the electron-ion screening factor. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Figures

Figure 1

Review

Jump to: Research

Open AccessFeature PaperReview Beyond the Linear Stark Effect: A Retrospective
Received: 1 March 2018 / Revised: 25 May 2018 / Accepted: 29 May 2018 / Published: 6 June 2018
Cited by 1 | PDF Full-text (1542 KB) | HTML Full-text | XML Full-text
Abstract
A review of studies of the electric-field influence on spectral lines is presented, beginning from the discovery of the Stark effect, and in particular focused on phenomena related to the effects of the plasma microfield non-uniformity. Full article
(This article belongs to the Special Issue Spectral Line Shapes in Plasmas II)
Back to Top