Electron-impact single ionization of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="normal">W</mml:mi><mml:none /><mml:mrow><mml:mn>19</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:mmultiscripts></mml:math>ions

Borovik, A.; Ebinger, B.; Schury, D.; Schippers, S.; Müller, A.

doi:10.1103/physreva.93.012708

Cited by 24 publications

(18 citation statements)

References 42 publications

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“…In order to be able to compare with the EISI data from the ADAS data base [35] plasma rate coefficients (PRC) for ionisation of W 11+ to W 18+ ions were derived from the present experimental cross sections using the procedures employed already for W 19+ [28]. Accordingly, the experimental cross section is multiplied by the relative electron-ion velocity and the resulting product is integrated over a Maxwellian velocity distribution [46].…”

Section: Plasma Rate Coefficientsmentioning

confidence: 99%

“…Motivated by the importance of tungsten in modern fusion research, a comprehensive experimental programme on studying electron-ion recombination [24][25][26], electron-impact ionisation [27,28] and photoionisation [29][30][31][32] of tungsten ions has been launched [1]. As a part of this campaign, the present study addresses electron-impact single ionisation (EISI) of W q+ ions with charge states 11 ≤ q ≤ 18, thus, extending previous experimental work on EISI of tungsten ions with charge states in the range 1-10 [33].…”

Section: Introductionmentioning

confidence: 99%

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Electron-impact single ionisation of W^q+ions: experiment and theory for 11 ≤ q ≤ 18

Schury

Borovik

Ebinger

et al. 2019

J. Phys. B: At. Mol. Opt. Phys.

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Absolute cross sections for electron-impact single ionisation (EISI) of multiply charged tungsten ions (W q+ ) with charge states in the range 11 ≤ q ≤ 18 in the electron-ion collision energy ranges from below the respective ionisation thresholds up to 1000 eV were measured employing the electron-ion crossed-beams method. In order to extend the results to higher energies, cross section calculations were performed using the subconfiguration-averaged distorted-wave (SCADW) method for electron-ion collision energies up to 150 keV. From the combined experimental and scaled theoretical cross sections rate coefficients were derived which are compared with the ones contained in the ADAS database and which are based on the configuration-averaged distorted wave (CADW) calculations of Loch et al. [Phys. Rev. A 72, 052716 (2005)]. Significant discrepancies were found at the temperatures where the ions investigated here are expected to form in collisionally ionised plasmas. These discrepancies are attributed to the limitations of the CADW approach and also the more detailed SCADW treatment which do not allow for a sufficiently accurate description of the EISI cross sections particularly at the ionisation thresholds.

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Section: Plasma Rate Coefficientsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electron-impact single ionisation of W^q+ions: experiment and theory for 11 ≤ q ≤ 18

Schury

Borovik

Ebinger

et al. 2019

J. Phys. B: At. Mol. Opt. Phys.

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“…R-matrix theory is a tool to obtain information about electron-ion and photon-ion interactions in general. Electron-impact ionization and recombination of tungsten ions have been studied experimentally [30,31,32,33,34,35,36,37] while there are no detailed measurements on electron-impact excitation of tungsten atoms in any charge state. Thus, the present study on photoionization of these complex systems and comparison of the experimental data with R-matrix calculations provides benchmarks and guidance for future theoretical work on electron-impact excitation.…”

Section: Photoionization Of Tungsten (W) Ions: W 2+ and W 3+mentioning

confidence: 99%

PAMOP Project: Computations in Support of Experiments and Astrophysical Applications

McLaughlin

Ballance

Pindzola

et al. 2016

High Performance Computing in Science and Engineering ´16

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Our computation effort is primarily concentrated on support of current and future measurements being carried out at various synchrotron radiation facilities around the globe, and photodissociation computations for astrophysical applications. In our work we solve the Schrödinger or Dirac equation for the appropriate collision problem using the R-matrix or R-matrix with pseudo-states approach from first principles. The time dependent close-coupling (TDCC) method is also used in our work. A brief summary of the methodology and ongoing developments implemented in the R-matrix suite of Breit-Pauli and Dirac-Atomic R-matrix codes (DARC) is presented.

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“…Good agreement between the experimental cross section [8] and the theoretical cross section was found when a reasonable assumption for the initial state population in the experiment was made. A similar approach as the one of Loch et al [4] was used in a joint experimental and theoretical study for q = 19 by Borovik Jr. et al [10] who showed that the inclusion of excitation-autoionisation (EA) involving high-n levels up to n max = 23 leads to better agreement between experiment and theory also close to the threshold as compared to the results of Loch et al [4] who limited their calculations to n max = 8. The importance of high-n EA channels has also been pointed out in a sequence of theoretical studies for q = 25 − 27 by Jonauskas et al [11] and Kynienė et al [12,13].…”

Section: Introductionmentioning

confidence: 99%

Electron-impact single ionisation of W14+ ions: Subconfiguration-average and level-to-level distorted wave calculations

Jin,

Borovik,

Ebinger

et al. 2019

Preprint

Self Cite

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The cross section for electron-impact single ionisation of W 14+ ions has been calculated by using two different approaches, i.e., the subconfiguration averaged distorted-wave (SCADW) method and the more involved level-to-level distorted-wave (LLDW) method. Both methods are found to yield very similar results except for the 4d → 5d excitation-autoionisation (EA) channels that straddles the ionisation threshold. Accordingly, a hybrid theoretical cross section where the 4d → 5d EA SCADW cross section is replaced by its LLDW counterpart is in good agreement with the experimental result from an electron-ion crossedbeams experiment. This is in contrast to pure SCADW calculations for W 14+ and neighbouring charge states which exhibit significant deviations from the experimental near-threshold cross sections of Schury et al. [2020 J. Phys. B 53 015201].

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Electron-impact single ionization ofW19+ions

Cited by 24 publications

References 42 publications

Electron-impact single ionisation of W^q+ions: experiment and theory for 11 ≤ q ≤ 18

Electron-impact single ionisation of W^q+ions: experiment and theory for 11 ≤ q ≤ 18

PAMOP Project: Computations in Support of Experiments and Astrophysical Applications

Electron-impact single ionisation of W14+ ions: Subconfiguration-average and level-to-level distorted wave calculations

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Electron-impact single ionization ofW19+ions

Cited by 24 publications

References 42 publications

Electron-impact single ionisation of W q+ions: experiment and theory for 11 ≤ q ≤ 18

Electron-impact single ionisation of W q+ions: experiment and theory for 11 ≤ q ≤ 18

PAMOP Project: Computations in Support of Experiments and Astrophysical Applications

Electron-impact single ionisation of W14+ ions: Subconfiguration-average and level-to-level distorted wave calculations

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Electron-impact single ionisation of W^q+ions: experiment and theory for 11 ≤ q ≤ 18

Electron-impact single ionisation of W^q+ions: experiment and theory for 11 ≤ q ≤ 18