Effects of Ion Motion on Hydrogen Stark Profiles

Seidel, Joachim

doi:10.1515/zna-1977-1102

Cited by 80 publications

(13 citation statements)

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“…In fact, their incorporation results in an increase of the L half-width by a factor of about 2 and, furthermore, leads to a remarkable reduction of the dip in the center of L& [37][38][39][40], while for H the half-width TABLE I. Electron shift of the H line at -' of the intensity maximum (n, =10' cm, T=12000 K). decreases only by about 15% [34,41] for the discussed plasma conditions.…”

Section: Approximationsmentioning

confidence: 99%

Hydrogen spectral lines with the inclusion of dense-plasma effects

Günter

Hitzschke²,

Röpke

1991

Phys. Rev. A

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Line profiles for hydrogen including the case of dense plasmas are investigated on the basis of a many-particle approach. Using a Green s-function technique, electron contributions to the shift and broadening from both separate-level and interferencelike terms are considered consistently. The theoretical approach to the line profile has been improved by including dynamic screening of collisions, contributions from hn =0 transitions, and cross-term contributions not only to the broadening but also to the shift of the line. As an example, the line profile of H has been considered. An analysis of details of the second-order approximation with respect to the atom-plasma interaction is given, avoiding the noquenching and dipole approximations. The effect of dynamic screening for high electron densities is investigated. Deviations from the linear dependence between the electron-shift contribution and the density are expected for H for n, &2X10" cm at temperatures of about 10000 K. PACS number(s): 52.25.Rv, 32.70.Jz I. INTRODUCTIGN

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Section: Approximationsmentioning

confidence: 99%

Hydrogen spectral lines with the inclusion of dense-plasma effects

Günter

Hitzschke²,

Röpke

1991

Phys. Rev. A

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“…Within the assumptions of ST the plasma ions are considered as static [17,18,21], and hence the resultant Stark profiles are called static or quasistatic. We now consider the ion dynamics effects, i.e., the deviations from the static Stark profiles due to the thermal motion (see, for example, [7][8][9]12,17,18,20,21,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][74][75][76]). If these deviations are small enough (called in earlier works "thermal corrections" The basic idea of Markov construction of these joint distributions is that , F F    and F   are stochastic independent variables, formed by summation of electric fields or its derivatives over all individual ions of the medium [1,5,6].…”

Section: Ion Dynamics In Statistical and Spectral Characteristics Of mentioning

confidence: 99%

“…Thus, simultaneously with the computer simulations the development of model approaches, that accounted for the ion dynamical effects in an approximate manner, were carried on independently [32][33][34][35][36][37]39,41,46,49,53,54,56,[59][60][61][62][63][64][68][69][70][71][72][73][74][75][76]. The first such model (actually, predating computer simulations) was MMM [14,15,28,29,52], later followed by various applications of the BID [37,71] and Frequency Fluctuation Model (FFM) [46,56,66] methods. Notably, neither of these models explicitly accounts for the effects of microfield rotation [24,25,30,33,53].…”

Section: Thus This Comparison Demonstrates An Acceptable Accuracy Of mentioning

confidence: 99%

“…The necessity of this discussion arose when it was recently shown that existing approaches to accounting for ion dynamics give results that differ from one another [74][75][76]. This inspired attempts to describe ion dynamics effects in terms of physical mechanisms, instead of practically tacit conventional numerical comparison of complicated simulations that began with the first works done using the Model Microfield Method (MMM) in the 1970s [14,15,28,29]. The basics of the theory of thermal corrections for Stark profiles along with the results of [7][8][9]12,[23][24][25] are given in Section 3.…”

Section: Introductionmentioning

confidence: 99%

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Spectral-Kinetic Coupling and Effect of Microfield Rotation on Stark Broadening in Plasmas

Demura

Stambulchik

2014

Atoms

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The study deals with two conceptual problems in the theory of Stark broadening by plasmas. One problem is the assumption of the density matrix diagonality in the calculation of spectral line profiles. This assumption is closely related to the definition of zero wave functions basis within which the density matrix is assumed to be diagonal, and obviously violated under the basis change. A consistent use of density matrix in the theoretical scheme inevitably leads to interdependence of atomic kinetics, describing the population of atomic states with the Stark profiles of spectral lines, i.e., to spectral-kinetic coupling. The other problem is connected with the study of the influence of microfield fluctuations on Stark profiles. Here the main results of the perturbative approach to ion dynamics, called the theory of thermal corrections (TTC), are presented, within which the main contribution to effects of ion dynamics is due to microfield fluctuations caused by rotations. In the present study the qualitative behavior of the Stark profiles in the line center within predictions of TTC is confirmed, using non-perturbative computer simulations.

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“…Several theoretical approaches have been applied to calculate Stark broadening, such as the well known semiclassical approximation the standard theory (ST) by Griem [1], or the quantum statistical approach of many-particle theory [2], where the motion of ion perturber is neglected during the inverse halfwidth of the line. Furthermore, the model microfield method (MMM) [3][4][5][6], the frequency fluctuation method (FFM) [7] or computer simulations [8][9][10][11] are used for calculating the line broadening including ion-dynamics effects, which lead to further broadening of the line shapes.…”

Section: Introductionmentioning

confidence: 99%

Spectral Line Shapes of He I Line 3889 Å

Omar

González

et al. 2014

Atoms

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Spectral line shapes of neutral helium 3889 Å (2 3 S-3 3 P ) transition line are calculated by using several theoretical methods. The electronic contribution to the line broadening is calculated from quantum statistical many-particle theory by using thermodynamic Green's function, including dynamic screening of the electron-atom interaction. The ionic contribution is taken into account in a quasistatic approximation, where a static microfield distribution function is presented. Strong electron collisions are consistently considered with an effective two-particle T-matrix approach, where Convergent Close Coupling method gives scattering amplitudes including Debye screening for neutral helium. Then the static profiles converted to dynamic profiles by using the Frequency Fluctuation Model. Furthermore, Molecular Dynamics simulations for interacting and independent particles are used where the dynamic sequence of microfield is taken into account. Plasma parameters are diagnosed and good agreements are shown by comparing our

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Effects of Ion Motion on Hydrogen Stark Profiles

Cited by 80 publications

References 1 publication

Hydrogen spectral lines with the inclusion of dense-plasma effects

Hydrogen spectral lines with the inclusion of dense-plasma effects

Spectral-Kinetic Coupling and Effect of Microfield Rotation on Stark Broadening in Plasmas

Spectral Line Shapes of He I Line 3889 Å

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