Journal of Physics B: Atomic, Molecular and Optical Physics最新文献_第5页

R-matrix calculations for opacities: I. Methodology and computations 不透明度的 R 矩阵计算：I. 方法和计算

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-05-16 DOI: 10.1088/1361-6455/ad421c

A K Pradhan, S N Nahar and W Eissner

{"title":"R-matrix calculations for opacities: I. Methodology and computations","authors":"A K Pradhan, S N Nahar and W Eissner","doi":"10.1088/1361-6455/ad421c","DOIUrl":"https://doi.org/10.1088/1361-6455/ad421c","url":null,"abstract":"An extended version of the R-matrix methodology is presented for calculation of radiative parameters for improved plasma opacities. Contrast and comparisons with existing methods primarily relying on the distorted wave approximation are discussed to verify accuracy and resolve outstanding issues, particularly with reference to the opacity project (OP). Among the improvements incorporated are: (i) large-scale Breit–Pauli R-matrix calculations for complex atomic systems including fine structure, (ii) convergent close coupling wave function expansions for the (e + ion) system to compute oscillator strengths and photoionization cross sections, (iii) open and closed shell iron ions of interest in astrophysics and experiments, (iv) a treatment for plasma broadening of autoionizing resonances as function of energy-temperature-density dependent cross sections, (v) a ‘top-up’ procedure to compare convergence with R-matrix calculations for highly excited levels, and (vi) spectroscopic identification of resonances and bound (e + ion) levels. The present R-matrix monochromatic opacity spectra are fundamentally different from OP and lead to enhanced Rosseland and Planck mean opacities. An outline of the work reported in other papers in this series and those in progress is presented. Based on the present re-examination of the OP work, opacities of heavy elements might require revisions in high temperature-density plasma sources.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"8 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141061658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

R-matrix calculations for opacities: III. Plasma broadening of autoionizing resonances 不透明的 R 矩阵计算：III.自电离共振的等离子体展宽

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-05-16 DOI: 10.1088/1361-6455/ad421d

A K Pradhan

{"title":"R-matrix calculations for opacities: III. Plasma broadening of autoionizing resonances","authors":"A K Pradhan","doi":"10.1088/1361-6455/ad421d","DOIUrl":"https://doi.org/10.1088/1361-6455/ad421d","url":null,"abstract":"A general formulation is employed to study and quantitatively ascertain the effect of plasma broadening of intrinsic autoionizing (AI) resonances in photoionization cross sections. In particular, R-matrix data for iron ions described in the previous paper in the RMOP series (RMOP-II, hereafter RMOP2) are used to demonstrate underlying physical mechanisms due to electron collisions, ion microfields (Stark), thermal Doppler effects, core excitations, and free–free transitions. Breit–Pauli R-matrix cross sections for a large number of bound levels of Fe ions are considered, 454 levels of Fe XVII, 1184 levels of Fe XVIII and 508 levels of Fe XIX. Following a description of theoretical and computational methods, a sample of results is presented to show significant broadening and shifting of AI resonances due to extrinsic plasma broadening as a function of temperature and density. The redistribution of AI resonance strengths broadly preserves their integrated strengths as well as the naturally intrinsic asymmetric shapes of resonance complexes which are broadened, smeared and flattened, eventually dissolving into the bound-free continua.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"28 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141061622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

R-matrix calculations for opacities: IV. Convergence, completeness, and comparison of relativistic R-matrix and distorted wave calculations for Fe xvii and Fe xviii 不透明的 R 矩阵计算：IV.铁 xvii 和铁 xviii 的相对论 R 矩阵和扭曲波计算的收敛性、完整性和比较

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-05-16 DOI: 10.1088/1361-6455/ad45f6

L Zhao, S N Nahar and A K Pradhan

{"title":"R-matrix calculations for opacities: IV. Convergence, completeness, and comparison of relativistic R-matrix and distorted wave calculations for Fe xvii and Fe xviii","authors":"L Zhao, S N Nahar and A K Pradhan","doi":"10.1088/1361-6455/ad45f6","DOIUrl":"https://doi.org/10.1088/1361-6455/ad45f6","url":null,"abstract":"To investigate the completeness of coupled channel (CC) Breit–Pauli R-matrix (BPRM) calculations for opacities we employ the relativistic distorted wave (RDW) method to complement (‘top-up’) and compare the BPRM photoionization cross sections for high- levels of both Fe xvii and Fe xviii . Good agreement is found with background photoionization cross sections using these two methods, which also ensures the correct matching of bound level cross sections for completeness. In order to top-up the CC-BPRM calculations, bound–bound transitions involving additional bound levels, and a large number of doubly-excited quasi-bound levels corresponding to BPRM autoionizing resonances described in the paper RMOPII are calculated using the RDW method. Photoionization cross sections in the high energy region are also computed and compared up to about 500 Ry, and contributions from higher core level excitations than BPRM are considered. The effect of configuration interaction is investigated, which plays a significant role in correctly reproducing some background cross sections. Due to the fact that the additional RDW levels correspond to high- bound levels that are negligibly populated according to the Mihalas–Hummer–Däppen equation-of-state (paper I), the effect on opacities is expected to be small.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"43 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141061659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Superfluid fraction tensor of a two-dimensional supersolid 二维超固体的超流体分数张量

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-05-06 DOI: 10.1088/1361-6455/ad41c1

P B Blakie

引用次数: 0

Muon-induced nuclear magnetic moments in spinless muonic atoms: a simple estimate 无自旋μ介子原子中的μ介子诱导核磁矩：简单估算

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-04-25 DOI: 10.1088/1361-6455/ad38a9

K A Beyer and N S Oreshkina

引用次数: 0

Shortcuts to adiabaticity: theoretical framework, relations between different methods, and versatile approximations 绝热捷径：理论框架、不同方法之间的关系以及通用近似值

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-04-21 DOI: 10.1088/1361-6455/ad38f1

Takuya Hatomura

引用次数: 0

Faster than a speeding bullet—the 2023 Physics Nobel Prize 比子弹还快--2023 年诺贝尔物理学奖

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-04-11 DOI: 10.1088/1361-6455/ad3600

Marc Vrakking

引用次数: 0

Excitation and recombination studies with silicon and sulphur ions at an EBIT 硅和硫离子在 EBIT 条件下的激发和重组研究

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-04-02 DOI: 10.1088/1361-6455/ad31ad

I Orban, S Mahmood, T Fritjof, E Lindroth, C Z Dong, J l Rui, L Y Xie, R Schuch

{"title":"Excitation and recombination studies with silicon and sulphur ions at an EBIT","authors":"I Orban, S Mahmood, T Fritjof, E Lindroth, C Z Dong, J l Rui, L Y Xie, R Schuch","doi":"10.1088/1361-6455/ad31ad","DOIUrl":"https://doi.org/10.1088/1361-6455/ad31ad","url":null,"abstract":"Measurements of electron-impact excitation and recombination rate coefficients of highly charged Si and S ions at the Stockholm electron beam ion trap are reported. The experimental method was a combination of photon detection from the trapped ions during probing and subsequently extraction and time-of-flight (TOF) charge analysis of these ions. The TOF technique allows to measure recombination rate coefficients separately for every charge state, and together with the photon spectra of these ions also the excitation rate coefficients. In this paper, we present more details of the experimental procedure and summarize the experimental results in comparison with two different state-of-the-art calculations of recombination and excitation rates for Si10+–Si13+ and S12+–S15+ ions. One of these uses a relativistic configuration interaction approach (flexible atomic code) and the other is a relativistic many-body perturbation theory. A good to excellent agreement with both of them is found in energy and resonance strength for the investigated ions.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"32 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Entanglement dynamics of two non-Hermitian qubits 两个非赫米提质子的纠缠动力学

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-03-26 DOI: 10.1088/1361-6455/ad34a0

Yi-Xi Zhang, Zhen-Tao Zhang, Xiao-Zhi Wei, Bao-Long Liang, Feng Mei, Zhen-Shan Yang

引用次数: 0

Enhanced positron acceleration driven by femto-second laser pulses irradiating structured targets 飞秒激光脉冲照射结构化目标所驱动的增强型正电子加速度

IF 1.6 4区物理与天体物理

Journal of Physics B: Atomic, Molecular and Optical Physics Pub Date : 2024-03-21 DOI: 10.1088/1361-6455/ad31b1

S Chintalwad, S Krishnamurthy, S Ghosh, C P Ridgers, B Ramakrishna

{"title":"Enhanced positron acceleration driven by femto-second laser pulses irradiating structured targets","authors":"S Chintalwad, S Krishnamurthy, S Ghosh, C P Ridgers, B Ramakrishna","doi":"10.1088/1361-6455/ad31b1","DOIUrl":"https://doi.org/10.1088/1361-6455/ad31b1","url":null,"abstract":"We have proposed a compact scheme for generating high-density and high-energy positrons by irradiating different shaped targets with an ultra-intense laser pulse, using 2D particle-in-cell simulations and numerical analysis. Our simulations show that the Breit–Wheeler process dominates positron production during laser-target interaction when a laser with an intensity of <inline-formula>\u0000<tex-math><?CDATA $4 times 10^{23}~mathrm{W,cm}^{-2}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:mn>4</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mn>23</mml:mn></mml:mrow></mml:msup><mml:mtext> </mml:mtext><mml:msup><mml:mrow><mml:mi mathvariant=\"normal\">W</mml:mi><mml:mstyle scriptlevel=\"0\"></mml:mstyle><mml:mi>cm</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"bad31b1ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> is used. We obtain a positron beam with an energy of 2.5 GeV and a total number exceeding 109, which is an improvement by two orders of magnitude compared to previous work with the same laser intensity. By using different shaped targets, we are able to generate a high-energy positron beam with low divergence. The yield of positron pairs depends on both the target and the laser parameters, and we have investigated how the shape of the target can enhance pair production and reduce divergence. Both of our analytical and simulation results demonstrate that this high-flux and low-divergence positron beam has direct applications in the field of medical and astro-physics that can be explored in the upcoming high intensity laser facilities.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"117 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0