Accelerated recombination due to resonant deexcitation of metastable states

Ralchenko, Yuri; Maron, Y.

doi:10.1016/s0022-4073(01)00102-9

Cited by 160 publications

(74 citation statements)

References 31 publications

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“…We scanned the plasma volume at distances between 1 mm and 10 mm from the target surface, measuring the absolute intensities and temporal evolution of the Li i 2s-2p, 2p-3d, and 2p-4d transitions. Based on these measurements and using collisional-radiative modeling [21], it was found that the electron density in this plasma region varies between 10 14 and 10 13 cm −3 . For these measurements the spectral overlap of the allowed and the forbidden emissions must be minimized.…”

Section: Methodsmentioning

confidence: 98%

Determination of the Li I 4d–4f Energy Separation Using Active Spectroscopy

Tsigutkin¹,

Stambulchik²,

Maron³

et al. 2005

Phys. Scr.

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An accurate knowledge of the Li i 4d-4f energy separation is essential for the determination of electric fields, as is pursued using several modern diagnostic techniques. However, there is a rather large spread in the values of this quantity in the available data sources. We have measured the Li i 4d-4f energy separation using a technique that combines laser-induced-fluorescence with the utilization of collisional excitations. The plasma used for these measurements is laser-produced, which allows for selection of an electron-density range for which line shifts due to the plasma microfields are sufficiently small. An observation of the forbidden 2p-4f line provides the information on the microfields that allows for accounting for the Stark-shifts and evaluating the 4d-4f energy separation in the field-free limit. A comparison of the measured value with a few previous measurements allows for resolving the uncertainties in this quantity.

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Section: Methodsmentioning

confidence: 98%

Determination of the Li I 4d–4f Energy Separation Using Active Spectroscopy

Tsigutkin¹,

Stambulchik²,

Maron³

et al. 2005

Phys. Scr.

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“…Calculations of the level populations and line intensities expected from non-Maxwellian plasmas were performed with the collisional-radiative (CR) code NOMAD (Ralchenko & Maron 2001). This code allows modeling of plasma population kinetics for an arbitrary electron energy distribution function and was intensively used in simulations of emission from low-and medium-density plasmas (see, e.g., Arad et al 2000;Gregorian et al 2005).…”

Section: Methods Of Calculationmentioning

confidence: 99%

Is There a High‐Energy Particle Population in the Quiet Solar Corona?

Ralchenko

Feldman

Doschek

2007

ApJ

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A study of spectra emitted by the quiet solar corona indicates that the majority of line intensities originating in lowlying levels are consistent with isothermal plasma of $1:3 ; 10 6 K. Nevertheless, a number of line intensities and, in particular, those belonging to ions that are typical of higher temperatures are brighter than expected. We show in this paper that the excess brightness of the hotter lines may be satisfactorily accounted for by a two-Maxwellian electron distribution function. We have calculated the effects on the line intensities and ionization balance under the assumption of both single-and two-Maxwellian electron distribution functions. One Maxwellian is characterized by a temperature of about 110 eV (1:35 ; 10 6 K ). The second Maxwellian is assumed to be a high-energy component ranging in temperatures between 150 and 1000 eV, with electron fractions relative to the total electron density that vary from 0.5% to 10%. We found that a good match to the quiet-Sun intensities could be achieved by adding $5% electrons with a 300 Y 400 eV Maxwellian temperature to the cooler component at 110 eV. We also found that the calculated line intensities become inconsistent with the quiet solar corona measurements if more than 3% of a T e ¼ 500 eV plasma or more than 1% of a T e ¼ 1000 eV plasma is added to the cooler Maxwellian.

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“…The spectral modeling for the non-Maxwellian EBIT plasma was performed with the collisional-radiative code NOMAD [66] that has been extensively used in EBIT spectroscopy. The yttrium plasma was assumed to be in the steady state, optically thin and uniform with electron density of 10 11 cm −3 .…”

Section: Theoretical Modelingmentioning

confidence: 99%

Identification and Plasma Diagnostics Study of Extreme Ultraviolet Transitions in Highly Charged Yttrium

Silwal

Takács

Dreiling

et al. 2017

Atoms

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Abstract:Extreme ultraviolet spectra of the L-shell ions of highly charged yttrium (Y 26+ -Y 36+ ) were observed in the electron beam ion trap of the National Institute of Standards and Technology using a flat-field grazing-incidence spectrometer in the wavelength range of 4 nm-20 nm. The electron beam energy was systematically varied from 2.3 keV-6.0 keV to selectively produce different ionization stages. Fifty-nine spectral lines corresponding to ∆n = 0 transitions within the n = 2 and n = 3 shells have been identified using detailed collisional-radiative (CR) modeling of the non-Maxwellian plasma. The uncertainties of the wavelength determinations ranged between 0.0004 nm and 0.0020 nm. Li-like resonance lines, 2s-2p 1/2 and 2s-2p 3/2 , and the Na-like D lines, 3s-3p 1/2 and 3s-3p 3/2 , have been measured and compared with previous measurements and calculations. Forbidden magnetic dipole (M1) transitions were identified and analyzed for their potential applicability in plasma diagnostics using large-scale CR calculations including approximately 1.5 million transitions. Several line ratios were found to show strong dependence on electron density and, hence, may be implemented in the diagnostics of hot plasmas, in particular in fusion devices.

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Accelerated recombination due to resonant deexcitation of metastable states

Cited by 160 publications

References 31 publications

Determination of the Li I 4d–4f Energy Separation Using Active Spectroscopy

Determination of the Li I 4d–4f Energy Separation Using Active Spectroscopy

Is There a High‐Energy Particle Population in the Quiet Solar Corona?

Identification and Plasma Diagnostics Study of Extreme Ultraviolet Transitions in Highly Charged Yttrium

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