Quantifying the statistical noise in computer simulations of Stark broadening

Rosato, J.; Marandet, Y.; Stamm, R.

doi:10.1016/j.jqsrt.2020.107002

Cited by 13 publications

(9 citation statements)

References 28 publications

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“…Performing this average requires the use of a set of several thousands histories to ensure that the statistical noise remains weak. An alternative approach allowing a more efficient reduction of this noise has been recently proposed [ 9 ] but is not used here. The last step is the calculation of the line shape, which involves the use of a numerical Fourier transform:

I false(ω false) = \frac{1}{π} Re \int_{0}^{normal∞} C false(t false) \exp false(i ω t false) dt .

…”

Section: Computer Simulation Of Dynamic Stark Effectmentioning

confidence: 99%

Spectroscopic diagnostic of oscillating electric fields in edge plasmas

Hannachi

Stamm

Rosato

et al. 2022

Contributions to Plasma Physics

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The changes of plasma radiative properties in the presence of oscillating electric fields can be used for a diagnostic of the electric fields in the edge plasma. We present the modelling of hydrogen line shapes emitted in edge plasmas where powerful radio frequency (RF) waves are launched. RF waves are used for plasma heating and current drive, and understanding the details of their coupling to the plasma is an important issue in tokamak physics. Our model relies on a computer simulation of the plasma microfield and retains the emitter quantum evolution by solving numerically the Schrödinger equation. We calculate Lyman and Balmer lines of hydrogen in conditions where a significant part of the central intensity is transferred to satellite components under the simultaneous effects of the oscillating field and stochastic plasma microfield.

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I false(ω false) = \frac{1}{π} Re \int_{0}^{normal∞} C false(t false) \exp false(i ω t false) dt .

…”

Section: Computer Simulation Of Dynamic Stark Effectmentioning

confidence: 99%

Spectroscopic diagnostic of oscillating electric fields in edge plasmas

Hannachi

Stamm

Rosato

et al. 2022

Contributions to Plasma Physics

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“…Finally, in order to simulate an ensemble average over plasma configurations, a very large number of electric field time series is computed. Such an approach is computationally feasible for such non-interacting simulations and has been employed in many previous calculations (e.g., Gigosos and Cardeñoso, 1987;Stambulchik and Maron, 2006;Djurović et al, 2009;Rosato et al, 2020). We note that there is not agreement in the community whether the Debye shielding in these calculations should include screening by both electrons and protons, or just electrons.…”

Section: Distribution Of Electric Fieldsmentioning

confidence: 99%

“…Xenomorph is a simulation-based line profile code developed by T. Gomez (Gomez, 2013;Gomez et al, 2016), and which was recently updated by Cho (2021). While many simulation-based approaches have been made in the literature (e.g., Gigosos and Cardeñoso, 1987;Stambulchik and Maron, 2006;Djurović et al, 2009;Rosato et al, 2020;Tremblay et al, 2020), to our knowledge Xenomorph is the first such code to include a numerical implementation of OP.…”

Section: Implementation In Xenomorphmentioning

confidence: 99%

Hydrogen Line Shape Uncertainties in White Dwarf Model Atmospheres

Montgomery

Dunlap

Cho

et al. 2022

Front. Astron. Space Sci.

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For isolated white dwarf (WD) stars, fits to their observed spectra provide the most precise estimates of their effective temperatures and surface gravities. Even so, recent studies have shown that systematic offsets exist between such spectroscopic parameter determinations and those based on broadband photometry. These large discrepancies (10% in Teff, 0.1 M⊙ in mass) provide scientific motivation for reconsidering the atomic physics employed in the model atmospheres of these stars. Recent simulation work of ours suggests that the most important remaining uncertainties in simulation-based calculations of line shapes are the treatment of 1) the electric field distribution and 2) the occupation probability (OP) prescription. We review the work that has been done in these areas and outline possible avenues for progress.

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“…More elaborate techniques using dedicated models and codes can be used (e.g., see reports of previous SLSP workshops [8,9]). In the following, we report on computer simulations performed using a code developed previously for tokamak plasma spectroscopy applications [10,11]. The Zeeman effect is retained by adding the term −µ•B (with µ being the magnetic moment) to H 0 .…”

Section: Line Broadening Modelingmentioning

confidence: 99%

Hydrogen Line Shapes in Plasmas with Large Magnetic Fields

Rosato

2020

Atoms

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We report on hydrogen line shape calculations in the presence of an external magnetic field, at conditions such that the quadratic Zeeman effect is important. The latter is described through a term proportional to B2 in the Hamiltonian, accounting for atomic diamagnetism. It provides a shift and an asymmetry on Lorentz triplets, and it leads to the occurrence of forbidden components. Motivated by investigations performed at the fifth edition of the Spectral Line Shape in Plasmas (SLSP5) code comparison workshop, we perform new calculations of hydrogen Lyman line profiles. Field values representative of magnetized white dwarf atmosphere conditions are taken. The calculations are done using a computer simulation technique, designed for Stark broadening modeling. A discussion of the results is done in the framework of plasma diagnostics.

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Quantifying the statistical noise in computer simulations of Stark broadening

Cited by 13 publications

References 28 publications

Spectroscopic diagnostic of oscillating electric fields in edge plasmas

Spectroscopic diagnostic of oscillating electric fields in edge plasmas

Hydrogen Line Shape Uncertainties in White Dwarf Model Atmospheres

Hydrogen Line Shapes in Plasmas with Large Magnetic Fields

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