Cometary X-ray emission: theoretical cross sections following charge exchange by multiply charged ions of astrophysical interest

Otranto, S.; Olson, R E; Beiersdörfer, P.

doi:10.1139/p07-127

Cited by 7 publications

(4 citation statements)

References 23 publications

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“…These catalogues are useful for improving atomic modeling codes and for the analysis of spectra taken by space-based X-ray observatories, such as those of stellar coronae. Studies involving solar and cometary X-rays are detailed elsewhere in this issue [41][42][43]. The discovery of a new magnetic field X-ray diagnostic emission line in neonlike systems was also made at this facility.…”

Section: Discussionmentioning

confidence: 99%

Laboratory astrophysics in the extreme ultraviolet

Lepson¹,

Beiersdörfer²,

Bitter³

et al. 2008

Can. J. Phys.

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Electron beam ion traps are uniquely well suited for laboratory astrophysics because they can produce nearly any charge state of any element in a collisionally excited plasma that is comparable in density and temperature to many astronomical sources. The Lawrence Livermore EBIT facility has been optimized for laboratory astrophysics with a suite of dedicated instruments and has made significant advances in this field. This paper reviews some of the work performed at LLNL in compiling comprehensive spectral catalogues, discovery of a magnetic field line diagnostic in the EUV and soft X-ray regimes, and density diagnostics on EBIT and at the NSTX tokamak. PACS Nos.: 95.30.Ky, 32.30.Rj, 95.85.Nv, 97.10.Ex, 95.55.Ka, 95.85.Mt, 52.55.Fa Résumé : Les pièges ioniques à faisceau d'électrons sont extrêmement bien adaptés aux recherches en astrophysique dans le laboratoire, parce qu'ils peuvent produire pratiquement n'importe quel état de charge de n'importe quel élément dans des plasmas excités de densités comparables aux densités et températures de plusieurs sources astronomiques. L'appareil EBIT du Lawrence Livermore a été optimisé pour les recherches en astrophysique avec une série d'instruments dédiés et a permis des avances significatives dans ce domaine. Nous passons ici en revue certains travaux exécutés au LLNL , la compilation de catalogues spectraux, la découverte d'un diagnostique de lignes de champ magnétique dans les régimes EUV et X et des diagnostiques de densité sur EBIT et au tokamak NSTX.[Traduit par la Rédaction]

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Section: Discussionmentioning

confidence: 99%

Laboratory astrophysics in the extreme ultraviolet

Lepson¹,

Beiersdörfer²,

Bitter³

et al. 2008

Can. J. Phys.

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“…Results of theoretical calculations of single and multiple CE cross sections are also available. These calculations are made difficult by the many-electron and (for molecules) multi-center nature of the targets, and uncertainties in the Auger and Coster-Kronig transition rates (Olson et al 1989;Otranto et al 2008;Wu et al 2009;Simcic et al 2010).…”

Section: Introductionmentioning

confidence: 99%

MEASUREMENT AND CALCULATION OF ABSOLUTE SINGLE AND MULTIPLE CHARGE EXCHANGE CROSS SECTIONS FOR Fe^q⁺IONS IMPACTING H₂O

Simčič

Schultz

Mawhorter

et al. 2010

ApJ

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Charge exchange (CE) plays a fundamental role in the collisions of solar-and stellar-wind ions with lunar and planetary exospheres, comets, and circumstellar clouds. Reported herein are absolute cross sections for single, double, triple, and quadruple CE of Fe q+ (q = 5-13) ions with H 2 O at a collision energy of 7q keV. One measured value of the pentuple CE is also given for Fe 9+ ions. An electron cyclotron resonance ion source is used to provide currents of the highly charged Fe ions. Absolute data are derived from knowledge of the target gas pressure, target path length, and incident and charge-exchanged ion currents. Experimental cross sections are compared with new results of the n-electron classical trajectory Monte Carlo approximation. The radiative and non-radiative cascades following electron transfers are approximated using scaled hydrogenic transition probabilities and scaled Auger rates. Also given are estimates of cross sections for single capture, and multiple capture followed by autoionization, as derived from the extended overbarrier model. These estimates are based on new theoretical calculations of the vertical ionization potentials of H 2 O up to H 2 O 10+ .

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“…In addition, CX produces a significant amount of radiation in some laboratory plasmas, such as during neutral beam heating in tokamak plasmas. Identification and interpretation of the X-ray spectral signatures from charge exchange in complex sources, however, has been challenging because little targeted laboratory data are available, and while in some cases agreement between theory and measurement is good [6], in many significant discrepancies still exist [7,8,9]. To help better understand charge exchange The LLNL EBIT facility, home of the original EBIT [10,11], is well tested and has been used in numerous atomic physics and laboratory astrophysics experiments.…”

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confidence: 99%

“…In the CX case, the 1s2s 3 S 1 → 1s 2 1 S 0 forbidden line "z" is much stronger than the 1s2p 1 P 1 → 1s 2 1 S 0 resonance line "w", in stark contrast to the case of direct electron impact excitation. This well known spectral signature [4,6,8] can be used to identify the presence of CX as an X-ray production mechanism, even using a relatively low-resolution spectrometer, such as a CCD or germanium detector [16,17]. Figure 3 compares the high-n Rydberg X-ray lines produced by CX between Fe 26+ and neutral H 2 , N 2 , and He.…”

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confidence: 99%

Studies of X-ray production following charge exchange recombination between highly charged ions and neutral atoms and molecules

Brown

Beiersdörfer

Chen

et al. 2009

J. Phys.: Conf. Ser.

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Studies of X-ray production following charge exchange recombination between highly charged ions and neutral atoms and molecules Abstract. We have used microcalorimeters built by the NASA/Goddard Space Flight Center and the Lawrence Livermore National Laboratory SuperEBIT electron beam ion trap to measure X-ray emission produced by charge exchange reactions between highly charged ions colliding with neutral helium, hydrogen, and nitrogen gas. Our measurements show the spectral dependence on neutral species and also show the distinct differences between spectra produced by charge exchange reactions and those produced by direct electron-impact excitation. These results are part of an ongoing experimental investigation at the LLNL SuperEBIT facility of charge exchange spectral signatures and can be used to interpret X-ray spectra produced by a variety of laboratory and celestial sources including cometary and planetary atmospheres, the Earth's magnetosheath, the heliosphere, and tokamaks.

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Cometary X-ray emission: theoretical cross sections following charge exchange by multiply charged ions of astrophysical interest

Cited by 7 publications

References 23 publications

Laboratory astrophysics in the extreme ultraviolet

Laboratory astrophysics in the extreme ultraviolet

MEASUREMENT AND CALCULATION OF ABSOLUTE SINGLE AND MULTIPLE CHARGE EXCHANGE CROSS SECTIONS FOR Fe^q⁺IONS IMPACTING H₂O

Studies of X-ray production following charge exchange recombination between highly charged ions and neutral atoms and molecules

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Cometary X-ray emission: theoretical cross sections following charge exchange by multiply charged ions of astrophysical interest

Cited by 7 publications

References 23 publications

Laboratory astrophysics in the extreme ultraviolet

Laboratory astrophysics in the extreme ultraviolet

MEASUREMENT AND CALCULATION OF ABSOLUTE SINGLE AND MULTIPLE CHARGE EXCHANGE CROSS SECTIONS FOR Feq+IONS IMPACTING H2O

Studies of X-ray production following charge exchange recombination between highly charged ions and neutral atoms and molecules

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MEASUREMENT AND CALCULATION OF ABSOLUTE SINGLE AND MULTIPLE CHARGE EXCHANGE CROSS SECTIONS FOR Fe^q⁺IONS IMPACTING H₂O