Charge exchange, from the sky to the laboratory: A method to determine state‐selective cross‐sections for improved modeling

Betancourt-Martinez, Gabriele; Cumbee, Renata; Leutenegger, Maurice A.

doi:10.1002/asna.202023778

Cited by 4 publications

(3 citation statements)

References 25 publications

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“…However, these theoretical models have been sparsely tested (Lyons et al 2017;Liu et al 2022). Other simpler approaches include the scaling law for n capture (Janev & Winter 1985;Otranto et al 2006) and the analytical l distributions for approximating the lstate population (Janev & Winter 1985;Smith et al 2014), adopted in MCLZ for initial bare ions (Cumbee et al 2016;Lyons et al 2017;Betancourt-Martinez et al 2020). Recently, Mullen et al (2016) found that these l distributions struggle to accurately reflect the true l population for high-n capture (e.g., n ∼12-14), and proposed the shifted low-energy (SL1) distribution.…”

Section: Introductionmentioning

confidence: 99%

Measurement of n- and l-resolved State-selective Charge Exchange in Ar⁸⁺ Collision with He

Ren

Zhang

Wei

et al. 2022

ApJ

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The state-resolved capture cross sections for principal n and orbital angular momentum l play an important role in modeling soft X-ray emissions induced by charge exchange for many astrophysical environments. However, the empirical and semiclassical theories used to produce these data of n- and l-resolved state-selective capture have not been well tested. Using the cold target recoil ion momentum spectroscopy apparatus at Fudan University, we perform a series of measurements of Ar8+ ion charge exchange with He in the collision energy range from 1.4 to 20 keV u−1. We find that electrons are mainly captured in the n = 4 state of Ar7+ ions. This agrees with the prediction of the scaling law for n capture. Moreover, the relative cross sections are reported for 4s-, 4p-, 4d-, and 4f-resolved state-selective capture. The often used analytical l distributions in the astrophysical literature are evaluated by comparing to the measurements.

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Section: Introductionmentioning

confidence: 99%

Measurement of n- and l-resolved State-selective Charge Exchange in Ar⁸⁺ Collision with He

Ren

Zhang

Wei

et al. 2022

ApJ

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“…Spectral measurements of these collision systems at solar wind velocities with microcalorimeters (spectral resolution <10 eV) would be capable of measuring both individual Lyman ratios and the hardness ratio as a function of collision energy. Alternatively, the ℓ distribution of capture states could be extracted directly from high-resolution spectra using the methods developed and described by Betancourt-Martinez et al (2020), and would provide an invaluable benchmark of analytic ℓ distributions.…”

Section: Discussionmentioning

confidence: 99%

Time-dependent Lattice Cross Sections and Line Ratios for Solar Wind Charge Exchange: Bare Ne Incident on Atomic H and He

Bromley¹,

Pindzola²,

Bodewits³

et al. 2022

ApJS

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Charge exchange (CX) between highly charged ions and neutrals within the geocorona and heliosphere introduces a problematic background for every X-ray observation. For H-like ions the ℓ states within each n shell are degenerate. The majority of CX spectral models rely on calculated n-resolved cross sections, and the distribution of ℓ states is assumed to follow one of several analytical expressions. Laboratory data to validate these distributions at solar wind velocities is not available. Explicitly velocity-dependent calculations of n ℓ-resolved CX cross sections using the time-dependent lattice (TDL) method for Ne10+ incident on atomic H and He at 1–5 keV amu−1 are reported. The cross sections are incorporated into a radiative cascade model, and the influence of n- and n ℓ-resolved cross sections on possibly diagnostic emission line ratios is investigated. Comparisons of the ℓ distribution extracted from the TDL cross sections to the predominantly used analytical distributions reveals a consensus among n and n ℓ-resolved data at solar wind velocities, suggesting a statistical distribution is most appropriate for CX collisions involving atomic H. No consensus is found for atomic He targets, and the ℓ distribution extracted from n ℓ-resolved cross sections appears most appropriate. Open questions related to CX are discussed with emphasis on experimental methods to resolve them. Spectral measurements at an electron beam ion trap facility are planned to benchmark the presented cross section data.

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“…3(C)). The rate of error between the two images was calculated by the role mean square error (MSE) [12][13][14][15][16][17][18][19][20] using Eq. ( 1): ∑ where is the original image and is the image after coloring, where the error was 9%.…”

Section: The Work Of Colorationmentioning

confidence: 99%

Photometry technique to map elements’ distribution on comets’ nuclei surfaces by using the new method.

Hanash,

Z. Khalaf,

I. Abood

2023

IJP

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This study is unique in this field. It represents a mix of three branches of technology: photometry, spectroscopy, and image processing. The work treats the image by treating each pixel in the image based on its color, where the color means a specific wavelength on the RGB line; therefore, any image will have many wavelengths from all its pixels. The results of the study are specific and identify the elements on the nucleus’s surface of a comet, not only the details but also their mapping on the nucleus. The work considered 12 elements in two comets (Temple 1 and 67P/Churyumoy-Gerasimenko). The elements have strong emission lines in the visible range, which were recognized by our MATLAB program in the treatment of the image. The percentage of the elements was determined relative to iron, where in comet Temple 1, the most significant percentage of the element ratio potassium to iron is K / Fe ~ 28.2%, while the lowest value is Ca / Fe ~ 1.3%. For the comet, 67P/Churyumov-Gerasimenko, the most significant percentage of the elements relative to iron is also for potassium, K / Fe ~ 89.5%, while the lowest value is Ni / Fe ~ 0.26. In general, comparing both comets, the greatest percentage of the elements relative to iron is K / F. Iron is the base element in the structure of both comets, followed by potassium.

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Charge exchange, from the sky to the laboratory: A method to determine state‐selective cross‐sections for improved modeling

Cited by 4 publications

References 25 publications

Measurement of n- and l-resolved State-selective Charge Exchange in Ar⁸⁺ Collision with He

Measurement of n- and l-resolved State-selective Charge Exchange in Ar⁸⁺ Collision with He

Time-dependent Lattice Cross Sections and Line Ratios for Solar Wind Charge Exchange: Bare Ne Incident on Atomic H and He

Photometry technique to map elements’ distribution on comets’ nuclei surfaces by using the new method.

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Charge exchange, from the sky to the laboratory: A method to determine state‐selective cross‐sections for improved modeling

Cited by 4 publications

References 25 publications

Measurement of n- and l-resolved State-selective Charge Exchange in Ar8+ Collision with He

Measurement of n- and l-resolved State-selective Charge Exchange in Ar8+ Collision with He

Time-dependent Lattice Cross Sections and Line Ratios for Solar Wind Charge Exchange: Bare Ne Incident on Atomic H and He

Photometry technique to map elements’ distribution on comets’ nuclei surfaces by using the new method.

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Product

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Measurement of n- and l-resolved State-selective Charge Exchange in Ar⁸⁺ Collision with He

Measurement of n- and l-resolved State-selective Charge Exchange in Ar⁸⁺ Collision with He