{"title":"致密等离子体中的电子碰撞电离","authors":"Walter R. Johnson , Joseph Nilsen , K.T. Cheng","doi":"10.1016/j.hedp.2024.101153","DOIUrl":null,"url":null,"abstract":"<div><p>The distorted-wave with exchange (DWE) method is employed to evaluate electron impact ionization cross sections in dense electron–ion plasmas. Bound and continuum electron wave functions are obtained from a non-relativistic average-atom code. Plots of DWE cross sections are presented for <span><math><mrow><mn>1</mn><mi>s</mi></mrow></math></span> electrons in Li and Be plasmas and <span><math><mrow><mn>2</mn><mi>p</mi></mrow></math></span> electrons in Na and Mg plasmas. For each of these elements, cross sections are evaluated at metallic density in a range of temperatures from 10 to 100 eV and at their respective melting points. Resonances in the cross sections appear near the incident energy threshold at high temperatures. The origin of these resonances is discussed. In general, the distorted wave (DW) method without exchange is found to be a good approximation to the DWE method for electron impact ionization calculations. In the resonance region, however, exchange effects are found to be very important and cannot be neglected.</p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"53 ","pages":"Article 101153"},"PeriodicalIF":1.6000,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Electron impact ionization in dense plasmas\",\"authors\":\"Walter R. Johnson , Joseph Nilsen , K.T. Cheng\",\"doi\":\"10.1016/j.hedp.2024.101153\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The distorted-wave with exchange (DWE) method is employed to evaluate electron impact ionization cross sections in dense electron–ion plasmas. Bound and continuum electron wave functions are obtained from a non-relativistic average-atom code. Plots of DWE cross sections are presented for <span><math><mrow><mn>1</mn><mi>s</mi></mrow></math></span> electrons in Li and Be plasmas and <span><math><mrow><mn>2</mn><mi>p</mi></mrow></math></span> electrons in Na and Mg plasmas. For each of these elements, cross sections are evaluated at metallic density in a range of temperatures from 10 to 100 eV and at their respective melting points. Resonances in the cross sections appear near the incident energy threshold at high temperatures. The origin of these resonances is discussed. In general, the distorted wave (DW) method without exchange is found to be a good approximation to the DWE method for electron impact ionization calculations. In the resonance region, however, exchange effects are found to be very important and cannot be neglected.</p></div>\",\"PeriodicalId\":49267,\"journal\":{\"name\":\"High Energy Density Physics\",\"volume\":\"53 \",\"pages\":\"Article 101153\"},\"PeriodicalIF\":1.6000,\"publicationDate\":\"2024-08-28\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"High Energy Density Physics\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1574181824000788\",\"RegionNum\":3,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"PHYSICS, FLUIDS & PLASMAS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"High Energy Density Physics","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1574181824000788","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, FLUIDS & PLASMAS","Score":null,"Total":0}
引用次数: 0
摘要
采用带交换的扭曲波(DWE)方法来评估致密电子-离子等离子体中的电子碰撞电离截面。束缚和连续电子波函数是从非相对论平均原子代码中获得的。图中给出了 Li 和 Be 等离子体中 1s 电子以及 Na 和 Mg 等离子体中 2p 电子的 DWE 截面图。在 10 到 100 eV 的温度范围内,对每种元素的横截面都是在金属密度和各自的熔点下进行评估的。在高温入射能量阈值附近出现了截面共振。本文讨论了这些共振的起源。一般来说,在电子撞击电离计算中,无交换的扭曲波(DW)方法是 DWE 方法的良好近似方法。然而,在共振区,交换效应非常重要,不可忽视。
The distorted-wave with exchange (DWE) method is employed to evaluate electron impact ionization cross sections in dense electron–ion plasmas. Bound and continuum electron wave functions are obtained from a non-relativistic average-atom code. Plots of DWE cross sections are presented for electrons in Li and Be plasmas and electrons in Na and Mg plasmas. For each of these elements, cross sections are evaluated at metallic density in a range of temperatures from 10 to 100 eV and at their respective melting points. Resonances in the cross sections appear near the incident energy threshold at high temperatures. The origin of these resonances is discussed. In general, the distorted wave (DW) method without exchange is found to be a good approximation to the DWE method for electron impact ionization calculations. In the resonance region, however, exchange effects are found to be very important and cannot be neglected.
期刊介绍:
High Energy Density Physics is an international journal covering original experimental and related theoretical work studying the physics of matter and radiation under extreme conditions. ''High energy density'' is understood to be an energy density exceeding about 1011 J/m3. The editors and the publisher are committed to provide this fast-growing community with a dedicated high quality channel to distribute their original findings.
Papers suitable for publication in this journal cover topics in both the warm and hot dense matter regimes, such as laboratory studies relevant to non-LTE kinetics at extreme conditions, planetary interiors, astrophysical phenomena, inertial fusion and includes studies of, for example, material properties and both stable and unstable hydrodynamics. Developments in associated theoretical areas, for example the modelling of strongly coupled, partially degenerate and relativistic plasmas, are also covered.