Low-energy charge transfer between<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mi mathvariant="normal">C</mml:mi><mml:mrow><mml:mn>5</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>and atomic hydrogen

Draganić, Ilija; Seely, D. G.; Havener, C. C.

doi:10.1103/physreva.83.054701

Cited by 16 publications

(22 citation statements)

References 22 publications

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“…The experiment was conducted on the ORNL ion-atom merged-beam apparatus (see, e.g., Ref [20]), using the microcalorimeter x-ray detector from a University of Wisconsin and Goddard Space Flight Center sounding rocket experiment [21]. An all-permanent magnet electron cyclotron resonance (ECR) ion source on a high-voltage platform [20] produced highly charged m = 13 carbon ions which were momentum analyzed by a dipole magnet to produce an uncontaminated C 6+ beam.…”

Section: Methodsmentioning

confidence: 99%

“…An all-permanent magnet electron cyclotron resonance (ECR) ion source on a high-voltage platform [20] produced highly charged m = 13 carbon ions which were momentum analyzed by a dipole magnet to produce an uncontaminated C 6+ beam. Using both acceleration and deceleration off the platform, the C 6+ energy ranged from 462 to 32 300 eV/u which corresponds to velocities from 300 to 2500 km/s.…”

Section: Methodsmentioning

confidence: 99%

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X-ray emission measurements following charge exchange between C6+and He

et al. 2013

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X-ray spectra following charge-exchange collisions between C 6+ and He are presented for collision energies between 460 and 32 000 eV/u. Spectra were obtained at the Oak Ridge National Laboratory Multicharged Ion Research Facility using a microcalorimeter x-ray detector capable of fully resolving the C VI Lyman series lines through Ly-γ . These line ratios are sensitive to the initial electron distribution and test our understanding of the charge-exchange process. In addition, these line ratios are important for identifying charge exchange in astrophysical contexts involving the interaction of solar wind ions with neutrals. Our measurements are performed at collision velocities (300-2500 km/s) which overlap most of the solar wind range. Additional data of this type can be combined with computations to provide an extensive set of reliable line ratios and absolute cross sections for the interpretation of a variety of astrophysical situations.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

X-ray emission measurements following charge exchange between C6+and He

et al. 2013

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“…Ralchenko et al measured extreme ultraviolet spectra from Ca-like W 54+ to Na-like W 63+ [20], and magnetic-dipole lines among the 3d n levels of Co-like W 47+ to K-like W 55+ [21], at the National Institute of Standards and Technology (NIST) electron beam ion trap (EBIT) facility. Gillaspy et al [22] measured the 3s-3p D-line doublets in highly charged Na-like ions as well as the wavelengths of several 3s-3p 3/2 and 3p 1/2 -3d 3/2 lines in Si-, Al-, and Mg-like ions, including tungsten ions, at the same facility, though the experimental uncertainties reach half an electron volt for the j = 1/2 − 3/2 transitions.…”

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Relativistic configuration-interaction calculations of then=3-3 transition energies in highly charged tungsten ions

Chen

Cheng

2011

Phys. Rev. A

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A large-scale relativistic configuration-interaction calculation of the n = 3-3 transition energies for Ne-to Ar-like tungsten is carried out. The calculation is based on the relativistic no-pair Hamiltonian and uses finite B-spline orbitals in a cavity as basis functions. Quantum electrodynamic and mass polarization corrections are also included. Results are compared with other theories and with experiment, and are generally found to be more reliable than previous theoretical predictions. PACS number(s): 31.15.am, 31.15.ac, 32.30.Rj I. INTRODUCTIONTungsten is of interest in fusion research as it is a promising material in future magnetic confinement fusion reactors such as the ITER due to its desirable properties with low hydrogen retention, high melting point, and high thermal conductivity. However, since tungsten is a high-Z element, even with 10-20-keV reactor temperature, line emission in the x-ray and vacuum ultraviolet (VUV) regions is a major concern in realizing the magnetically confined fusion reactors. To understand its influence as a plasma impurity, reliable transition energy data are needed for many ionic stages of tungsten which show up in relevant emission spectra.There are not many experimental and theoretical studies in the literature for the n = 3-3 transition energies of highlycharged tungsten ions. Early calculations of the sodium isoelectronic sequence are mostly based on the Dirac-Fock (DF) [1-3] or model potential [4] methods with a relatively crude accuracy of a few electron volts. High-precision relativistic many-body perturbation theory (RMBPT) calculations of the correlation energies for selected Na-like ions were carried out by Johnson et al. [5], but quantum electrodynamic (QED) corrections, which are important for high-Z ions, were not included. Kim et al. [6] later used these RMBPT results to provide accurate relativistic correlation corrections to their DF energies for Na-like ions with 14 Z 92, and calculated the QED corrections with the ad hoc Welton method [7]. Reliable QED corrections from ab initio calculations were first given by Blundell [8], who added them to the RMBPT energies [5] to give accurate transition energies for a few Na-like ions, though tungsten was not included. Theoretical n = 3-3 resonance line energies for Mg-like ions include results from the multiconfiguration Dirac-Fock (MCDF) calculations by Cheng and Johnson [9] and Zou and Froese-Fischer [10], the relativistic random-phase approximation calculations by Shorer et al. [11], the relativistic perturbation calculations with model potentials by Ivanova et al. [12], and the relativistic configuration-interaction (RCI) calculations for low-to mid-Z ions by Chen and Cheng [13]. For the aluminum isoelectronic sequence, transition energies and radiative rates have been * chen7@llnl.gov † ktcheng@llnl.gov

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“…The charge exchange emission spectra of C 6+ on H 2 were measured by adapting the ion-atom merged beams apparatus at Oak Ridge National Laboratory [29] with an X-ray microcalorimeter detector from the University of Wisconsin and Goddard Space Flight Center sounding rocket experiment to measure Lyman emission from the resulting H-like C 5+ ion. A schematic of the experimental apparatus can be seen in Fig.…”

Section: Methodsmentioning

confidence: 99%

X-ray-emission measurements following charge exchange between C6+and H2

et al. 2014

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Lyman x-ray spectra following charge exchange between C 6+ and H 2 are presented for collision velocities between 400 and 2300 km/s (1-30 keV/amu). Spectra were measured by a microcalorimeter x-ray detector capable of fully resolving the C VI Lyman series emission lines though Lyman-δ.The ratios of the measured emission lines are sensitive to the angular momentum l-states populated during charge exchange and are used to gauge the effectiveness of different l-distribution models in predicting Lyman emission due to charge exchange. At low velocities, we observe that both single electron capture and double capture autoionization contribute to Lyman emission and that a statistical l-distribution best describes the measured line ratios. At higher velocities single electron capture dominates with the l-distribution peaked at the maximum l.Charge exchange (CX) between highly charged ions and atomic and molecular targets can exhibit large cross sections (10 −15 cm 2 ) at certain collision velocity regimes, making it one of the dominant processes in plasma environments. The resulting emission lines due to cascading captured electrons can provide temperature, density and relative abundance information about the interaction environment. In laboratory magnetic confinement plasmas, CX is a common diagnostic tool used in combination with puffed gas and neutral beams injection [1][2][3]. In astrophysical settings, the identification of x-ray emission from comets has been linked to CX between solar wind ions and ablated cometary neutral gases [4][5][6].These same solar wind ions interact with neutrals of planetary atmospheres and from the heliosphere. These applications have made CX modeling of paramount interest to both the laboratory plasma and astrophysics communities.A successful model of emission spectra due to CX relies on being able to map the specific distribution of principal, n, and angular momentum, l, quantum states in which the transferred electron is captured on the ion. Several successful tools have been developed to estimate the n-state of capture, however, the state-selective n, l CX cross sections are highly dependent on collision velocity and several models, of various effectiveness, have been put forth to estimate the l-distributions in CX over different collision velocity regimes.A number of previous theoretical and experimental studies helped to establish methods of determining CX cross sections and the principle quantum state n of capture for given interaction pairs and energies. In the regime where the collision velocity is approximately equal to the orbital velocity of the captured electron, the most successful tool has been the classical over-the-barrier model (CBM) [7]. At higher collision velocities, the classical trajectory Monte Carlo (CTMC) technique has shown to be successful [8]. At lower collision velocities, the CX process involves complex trajectories and interaction dynamics between many states and is best modeled by atomic orbital (or molecular orbital) close-coupling (AOCC, MOCC) methods [9...

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Low-energy charge transfer betweenC5+and atomic hydrogen

Cited by 16 publications

References 22 publications

X-ray emission measurements following charge exchange between C6+and He

X-ray emission measurements following charge exchange between C6+and He

Relativistic configuration-interaction calculations of then=3-3 transition energies in highly charged tungsten ions

X-ray-emission measurements following charge exchange between C6+and H2

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