Experimental discovery of charge-exchange-caused dips in spectral lines from laser-produced plasmas

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

doi:10.1103/physreve.64.065401

Cited by 14 publications

(11 citation statements)

References 9 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: 89%

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: 89%

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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Section: Hα Dip 22 Experimental Observations Of X-dipsmentioning

confidence: 99%

“…Laser Produced Plasma Experiments at LULI (Laboratoire pour l'Utilisation des Lasers Intenses) (E. Dalimier et al 2001). Later, the X-dips were observed in laser-produced plasmas characterized by a high electron density 10 22 -3 × 10 22 cm −3 [15,20]. The setup was implemented at the laser facility LULI using the same nanosecond laser at 10 14 W/cm 2 and the same high-resolution Vertical-geometry Johann Spectrometer (R = 8,000) as in the experiments devoted to the observation of L-dips [7,8].…”

Section: Hα Dip 22 Experimental Observations Of X-dipsmentioning

confidence: 99%

Review of Langmuir-Wave-Caused Dips and Charge-Exchange-Caused Dips in Spectral Lines from Plasmas and their Applications

Dalimier

Oks

Renner

2014

Atoms

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We review studies of two kinds of dips in spectral line profiles emitted by plasmas-dips that have been predicted theoretically and observed experimentally: Langmuir-wave-caused dips (L-dips) and charge-exchange-caused dips (X-dips). There is a principal difference with respect to positions of L-dips and X-dips relative to the unperturbed wavelength of a spectral line: positions of L-dips scale with the electron density N e roughly as N e 1/2 , while positions of X-dips are almost independent of N e (the dependence is much weaker than for L-dips). L-dips and X-dips phenomena are important, both fundamentally and practically. The fundamental importance is due to a rich physics behind each of these phenomena. L-dips are a multi-frequency resonance phenomenon caused by a singlefrequency (monochromatic) electric field. X-dips are due to charge exchange at anticrossings of terms of a diatomic quasi-molecule, whose nuclei have different charges. As for important practical applications, they are as follows: observations of L-dips constitute a very accurate method to measure the electron density in plasmas-a method that does not require knowledge of the electron temperature. L-dips also allow measuring the amplitude of the electric field of Langmuir waves-the only spectroscopic method available for this purpose. Observations of X-dips provide an opportunity to determine rate coefficient of charge exchange between multi-charged ions. This is an important reference data, virtually inaccessible by other experimental methods. The rate coefficients of charge

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“…The interest of high material density effects has been recently enhanced by spectroscopic measurements (line profiles, emission and absorption coefficients) from astrophysical or laboratory sources [30][31][32][33][34] corresponding to dense hot plasma situations For low Z materials (Z l6) the ionic correlation effects may provide new diagnostics for the measure of plasma macroscopic parameters or the knowledge of atomic/molecular processes, all these data being crucial for the knowledge of the state equations and the energy transfer in dense hot plasmas. An expertise has been achieved at LULl for the generation of ultradense hot plasma at high intensities ( l014Wcm2).…”

Section: Iv2 Ultrafast Ionization Dynamics and Plasma Physicsmentioning

confidence: 99%

<title>Status and overview of research programs at LULI 2000</title>

et al. 2001

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Experimental discovery of charge-exchange-caused dips in spectral lines from laser-produced plasmas

Cited by 14 publications

References 9 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

Review of Langmuir-Wave-Caused Dips and Charge-Exchange-Caused Dips in Spectral Lines from Plasmas and their Applications

<title>Status and overview of research programs at LULI 2000</title>

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