Advanced simulations of spectroscopic signatures of charge exchange in laser-produced plasmas

Leboucher-Dalimier, E.; Oks, Eugene; Dufour, E.; Angelo, P.; Sauvan, P.; Schott, René; Poquérusse, A.

doi:10.1140/epjd/e2002-00125-0

Cited by 8 publications

(8 citation statements)

References 3 publications

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“…A quasi crossing of the TCC terms, by enhancing charge exchange, can result in unusual structures (dips) in the spectral line profile emitted by a Z-ion from a plasma consisting of both Z-and Z′-ions, as was shown theoretically and experimentally [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 73%

Electric field induced crossings of energy terms of a Rydberg quasi molecule enhancing charge exchange and ionization

Kryukov

Oks

2012

Can. J. Phys.

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Charge exchange is one of the most important atomic processes in plasmas. Charge exchange and crossings of corresponding energy levels that enhance charge exchange are strongly connected with problems of energy losses and of diagnostics in high temperature plasmas. Charge exchange was also proposed as an effective mechanism for population inversion in the soft X-ray and vacuum ultraviolet ranges. One of the most fundamental theoretical domains for studying charge exchange is the problem of electron terms in the field of two stationary Coulomb centers (TCC) of charges Z and Z′ separated by a distance R. It presents an intriguing atomic physics: the terms can have crossings and quasi crossings. These intrinsic features of the TCC problem also manifest in different areas of physics, such as plasma spectroscopy: a quasi crossing of the TCC terms, by enhancing charge exchange, can result in an unusual structure (a dip) in the spectral line profile emitted by a Z-ion from a plasma consisting of both Z-and Z′-ions, as was shown theoretically and experimentally. Before the year 2000, the paradigm was that the preceding sophisticated features of the TCC problem and its flourishing applications were inherently quantum phenomena. In 2000, a purely classical description of the crossings of energy terms was presented. In the present paper we study the effect of an electric field (along the internuclear axis) on circular Rydberg states of the TCC system. We provide analytical results for strong fields, as well as numerical results for moderate fields. We show that the electric field has several effects. First, it leads to the appearance of an extra energy term: the fourth classical energy term -in addition to the three classical energy terms at zero field. Second, but more importantly, the electric field creates additional crossings of these energy terms. We show that some of these crossings significantly enhance charge exchange, while other crossings enhance the ionization of the Rydberg quasi molecule. PACS Nos: 32.60.+i, 32.80.Ee, 34.70.+e, 33.80.Be, 31.15.-pRésumé : L'échange de charge est le plus important mécanisme atomique dans les plasmas. L'échange de charge et le croisement des niveaux d'énergie correspondants qui augmente l'échange de charge sont fortement connectés aux problèmes de perte d'énergie et de diagnostique dans les plasmas de haute température. L'échange de charge a aussi été proposé comme un mécanisme efficace pour l'inversion de population dans les domaines VUV et rayon-X mou. Le problème des termes de l'électron dans le champ de deux centres coulombiens stationnaires (TCC) de charges Z et Z′ séparés par une distance R, est central dans l'étude de l'échange de charge. C'est un problème intriguant en physique atomique : les termes peuvent avoir des croisements et des quasi croisements. Ces caractéristiques intrinsèques se manifestent également dans d'autres domaines de la physique, comme la spectroscopie du plasma : un quasi croisement des termes TCC, par augmentation de l'échange de charge, peut donner ...

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Section: Introductionmentioning

confidence: 73%

Electric field induced crossings of energy terms of a Rydberg quasi molecule enhancing charge exchange and ionization

Kryukov

Oks

2012

Can. J. Phys.

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“…The quantity γ ≡ γ nonCE (R cr ) in equation ( 17), representing the frequency of inelastic collisions with electrons and ions leading to virtual transitions from the upper state of the radiator to other states, can be calculated for given plasma parameters N e , N i , T e and T i by using one of few contemporary theories (presented, e.g., in the recent book [9]) 5 .…”

Section: Determination Of the Rate Coefficient Of Charge Exchange Fro...mentioning

confidence: 99%

“…Charge exchange in dense plasmas can result in dips in spectral line profiles of hydrogenlike ions of a nuclear charge Z perturbed by fully-stripped ions of a different nuclear charge Z = Z. These so-called x-dips were described in detail theoretically and discovered experimentally in our previous works [1][2][3][4][5]. The positions of the x-dips practically do not depend on the electron density N e -in distinction to the Langmuir-wave-caused dips (see, e.g., [6][7][8] and references therein), whose positions significantly depend on N e .…”

Section: Introductionmentioning

confidence: 99%

“…The positions of the x-dips practically do not depend on the electron density N e -in distinction to the Langmuir-wave-caused dips (see, e.g., [6][7][8] and references therein), whose positions significantly depend on N e . In the previous studies of the x-dip phenomenon [1][2][3][4][5], the following two sets of questions have not been addressed.…”

Section: Introductionmentioning

confidence: 99%

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Experimental determination of rate coefficients of charge exchange fromx-dips in laser-produced plasmas

Dalimier¹,

Oks²,

Renner³

et al. 2007

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

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Charge exchange in dense plasmas can result in dips in spectral line profiles of hydrogenlike ions of a nuclear charge Z perturbed by fully-stripped ions of a different nuclear charge Z′ ≠ Z. These so-called x-dips were described in detail theoretically and discovered experimentally in our previous works. In the theoretical part of the present paper we show that the x-dip has a structure consisting of the dip itself surrounded by two adjacent bumps. We also show that two different explanations of the x-dip formation, provided in the previous papers, do not describe the same processes: they represent two independent mechanisms working simultaneously. Based on the obtained results, we provide for the first time a method for determining the rate coefficients of charge exchange from the measured shape of the x-dips, namely, from the bump-to-dip ratio of intensities. In the experimental part we present new results on the x-dips in the profile of the Lγ line of Al XIII in a laser-produced plasma. These new experimental data, obtained with a significantly better spectral resolution than in our previous experiments, allow observation for the first time not just of the dip itself (the central minimum), but the entire structure including two adjacent bumps. By combining our new theoretical and experimental results, we determined for the first time the rate coefficient of charge exchange between the hydrogenic Al and a fully-stripped C in the laser-produced plasma. This constitutes the next step towards the employment of the x-dip phenomenon for producing not-yet-available fundamental data on charge exchange between multicharged ions, virtually inaccessible by other experimental methods.

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“…In our previous works we discovered a way for producing not-yet-available fundamental data on CE between multicharged ions, virtually inaccessible by other experimental methods [1]. It was based on the formation of dips (called x-dips) in spectral lines of hydrogen-like ions from laserproduced plasmas [2][3][4][5][6][7]. The experiments were performed by international teams at two large multi-user laser facilities: at the European Union laser facility PALS located in Czech Republic and at the French multi-user laser facility LULI.…”

Section: Introductionmentioning

confidence: 99%

Analytical theory of charge-exchange-caused dips in spectral lines of He-like ions from laser-produced plasmas

Dalimier

Oks

2014

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

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Previously we discovered a way for producing not-yet-available fundamental data on charge exchange between multicharged ions, virtually inaccessible by other experimental methods. It was based on the formation of dips (called x-dips) in spectral lines of hydrogen-like ions from laser-produced plasmas. At that time the x-dip phenomenon was considered to be possible only in spectral lines of hydrogenic systems: due to the existence of exact algebraic (higher than geometrical) symmetries relevant only to hydrogenic systems and to the corresponding two-Coulomb-centre systems (dicentres) having one electron. In the present paper, by engaging the concept of an approximate algebraic symmetry of two-electron dicentres (and of helium-like ions), we opened up the way to significantly broaden the scope of experimental studies of the x-dip phenomenon-to studies of possible x-dips in spectral line profiles emitted by He-like ions in laser-produced plasmas. We identified three prospective two-electron dicentres and calculated analytically theoretical positions of the x-dips in the corresponding He-like spectral lines (though future experimental and theoretical studies should not be limited to these three two-electron dicentres). Since future experimental and theoretical studies should not be limited to these three two-electron dicentres, we presented also a table containing 15 prospective He-like spectral lines and 10 corresponding solid targets for observing x-dips in laser-produced plasmas. For completeness we presented also a similar table for H-like lines. It presented 16 prospective H-like spectral lines and 11 corresponding solid targets for observing x-dips in laser-produced plasmas. From the shape of experimental x-dips it is possible to determine the rate coefficient of charge exchange in the corresponding dicentre, as demonstrated previously. Therefore the results of the present paper should very significantly extend the range of fundamental data on charge exchange between multicharged ions that can be obtained via the x-dip phenomenon, but not by any other method.

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Advanced simulations of spectroscopic signatures of charge exchange in laser-produced plasmas

Cited by 8 publications

References 3 publications

Electric field induced crossings of energy terms of a Rydberg quasi molecule enhancing charge exchange and ionization

Electric field induced crossings of energy terms of a Rydberg quasi molecule enhancing charge exchange and ionization

Experimental determination of rate coefficients of charge exchange fromx-dips in laser-produced plasmas

Analytical theory of charge-exchange-caused dips in spectral lines of He-like ions from laser-produced plasmas

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