Ionization potential depression (IPD) is of crucial importance to understand and accurately predict the properties of dense, partially ionized plasmas. Many models of IPD have been developed that, however, exhibit largely varying results. Recently, a novel approach was proposed that is based on first-principles quantum Monte Carlo simulations and that was demonstrated for hydrogen. Here, this concept is discussed in more detail. Particular attention is devoted to the Fermi barrier that electrons have to overcome upon ionization and that significantly contributes to IPD when the nuclear charge increases.
{"title":"Ionization Potential Depression and Fermi Barrier in Warm Dense Matter: A First-Principles Approach","authors":"Michael Bonitz, Linda Kordts","doi":"10.1002/ctpp.70001","DOIUrl":"https://doi.org/10.1002/ctpp.70001","url":null,"abstract":"<p>Ionization potential depression (IPD) is of crucial importance to understand and accurately predict the properties of dense, partially ionized plasmas. Many models of IPD have been developed that, however, exhibit largely varying results. Recently, a novel approach was proposed that is based on first-principles quantum Monte Carlo simulations and that was demonstrated for hydrogen. Here, this concept is discussed in more detail. Particular attention is devoted to the Fermi barrier that electrons have to overcome upon ionization and that significantly contributes to IPD when the nuclear charge increases.</p>","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"65 8-9","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ctpp.70001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145426213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<div> <p>Atomic properties of warm dense matter are an active field of research. Understanding transport properties of these states is essential for providing coefficients needed by magneto-radiative-hydrodynamics codes for many studies, including hydrodynamic instabilities, energy balances or heating in fusion plasmas, difficult to investigate by experimental means. In this paper, we present an average-atom approach for the calculation of direct-current electric conductivity within Ziman's theory. The mean ion charge <span></span><math> <semantics> <mrow> <msup> <mi>Z</mi> <mo>*</mo> </msup> </mrow> <annotation>$$ {Z}^{ast } $$</annotation> </semantics></math>, commonly called ionization, is an important input of the Ziman formula, but is not clearly defined within average-atom models. Our study spans a wide range of thermodynamical conditions, that is, for the densities, from a few <span></span><math> <semantics> <mrow> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>2</mn> </mrow> </msup> </mrow> <annotation>$$ {10}^{-2} $$</annotation> </semantics></math> to about four times the solid's density, and, for the temperatures, typically from 0.1 to 700 eV, favorable to large differences in the mean ion charge <span></span><math> <semantics> <mrow> <msup> <mi>Z</mi> <mo>*</mo> </msup> </mrow> <annotation>$$ {Z}^{ast } $$</annotation> </semantics></math> according to its definition. We compare and discuss different ways of defining <span></span><math> <semantics> <mrow> <msup> <mi>Z</mi> <mo>*</mo> </msup> </mrow> <annotation>$$ {Z}^{ast } $$</annotation> </semantics></math> while trying to figure out which electrons really contribute to electric conduction. We compare our results with experimental data and published theoretical values, in particular from the second transport code comparison workshop, which was held in July 2023 at Lawrence Livermore National Laboratory. These comparisons lead us to propose indicators for the relevance of including different charges predicted by our average-atom model in the definition of <span></span><math> <semantics> <mrow> <msup> <mi>Z</mi> <mo>*</mo> </msup> </mrow> <annotation>$$ {Z}^{ast } $$</annotation> </s
{"title":"On the Electrons Really Contributing to DC Conductivity of Warm Dense Matter","authors":"Nadine Wetta, Jean-Christophe Pain","doi":"10.1002/ctpp.202500005","DOIUrl":"https://doi.org/10.1002/ctpp.202500005","url":null,"abstract":"<div>\u0000 \u0000 <p>Atomic properties of warm dense matter are an active field of research. Understanding transport properties of these states is essential for providing coefficients needed by magneto-radiative-hydrodynamics codes for many studies, including hydrodynamic instabilities, energy balances or heating in fusion plasmas, difficult to investigate by experimental means. In this paper, we present an average-atom approach for the calculation of direct-current electric conductivity within Ziman's theory. The mean ion charge <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>Z</mi>\u0000 <mo>*</mo>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {Z}^{ast } $$</annotation>\u0000 </semantics></math>, commonly called ionization, is an important input of the Ziman formula, but is not clearly defined within average-atom models. Our study spans a wide range of thermodynamical conditions, that is, for the densities, from a few <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mn>10</mn>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {10}^{-2} $$</annotation>\u0000 </semantics></math> to about four times the solid's density, and, for the temperatures, typically from 0.1 to 700 eV, favorable to large differences in the mean ion charge <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>Z</mi>\u0000 <mo>*</mo>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {Z}^{ast } $$</annotation>\u0000 </semantics></math> according to its definition. We compare and discuss different ways of defining <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>Z</mi>\u0000 <mo>*</mo>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {Z}^{ast } $$</annotation>\u0000 </semantics></math> while trying to figure out which electrons really contribute to electric conduction. We compare our results with experimental data and published theoretical values, in particular from the second transport code comparison workshop, which was held in July 2023 at Lawrence Livermore National Laboratory. These comparisons lead us to propose indicators for the relevance of including different charges predicted by our average-atom model in the definition of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>Z</mi>\u0000 <mo>*</mo>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {Z}^{ast } $$</annotation>\u0000 </s","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"65 8-9","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145426159","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}
Diagram of beam distribution of the magnetic trap at 50 ns with different beam incidence velocities. Green points represent protons, red points represent electrons and blue lines represent magnetic induction lines. Part of Fig. 6 of the paper by Fang-Ping Wang et al. https://doi.org/10.1002/ctpp.202400040
{"title":"Cover Picture: Contrib. Plasma Phys. 03/2025","authors":"","doi":"10.1002/ctpp.202590005","DOIUrl":"https://doi.org/10.1002/ctpp.202590005","url":null,"abstract":"<p>Diagram of beam distribution of the magnetic trap at 50 ns with different beam incidence velocities. Green points represent protons, red points represent electrons and blue lines represent magnetic induction lines. Part of Fig. 6 of the paper by Fang-Ping Wang et al. https://doi.org/10.1002/ctpp.202400040\u0000 \u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"65 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ctpp.202590005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fast and reliable plasma chemistry plays a crucial role in the fabrication of micro- and nanoscale structures in numerous applications. In this work, we demonstrated that fast and optimal etch chemistry using an inductively coupled plasma (ICP) system in combination with a simple and cost-effective dry film photoresist (DFR) as a mask transfer. The results show that the proposed DFR, which simultaneously removes the edge bead and air bubbles, can be successfully used in chlorinated and fluorinated chemistries, resulting in fast etching rates and good selectivity from 5:1 to 16:1 for GaAs and from 30:1 to 150:1 for silicon substrates. This solution offers the promise of drastically cutting down microfabrication time and minimizing contamination. It could pave the way for a novel, rapid manufacturing process that is applicable in various fields, regardless of the size or shape of the substrate.
{"title":"Prototyping of Si and III–V Compounds by Plasma Chemistry Using Dry Film Photoresist Mask","authors":"Etienne Herth, David Bouville, Samson Edmond","doi":"10.1002/ctpp.202400050","DOIUrl":"https://doi.org/10.1002/ctpp.202400050","url":null,"abstract":"<div>\u0000 \u0000 <p>Fast and reliable plasma chemistry plays a crucial role in the fabrication of micro- and nanoscale structures in numerous applications. In this work, we demonstrated that fast and optimal etch chemistry using an inductively coupled plasma (ICP) system in combination with a simple and cost-effective dry film photoresist (DFR) as a mask transfer. The results show that the proposed DFR, which simultaneously removes the edge bead and air bubbles, can be successfully used in chlorinated and fluorinated chemistries, resulting in fast etching rates and good selectivity from 5:1 to 16:1 for GaAs and from 30:1 to 150:1 for silicon substrates. This solution offers the promise of drastically cutting down microfabrication time and minimizing contamination. It could pave the way for a novel, rapid manufacturing process that is applicable in various fields, regardless of the size or shape of the substrate.</p>\u0000 </div>","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"65 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315229","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}
Md. Khairul Islam, Md. Sirajum Munir, Md. Afzal Hossain Talukder, M. A. Malek, Md. Salahuddin
Irradiation effect on the different plasma modes in various dusty plasma conditions was studied theoretically. We revisit our investigation on the instability of the electrostatic dust acoustic (DA) mode elaborately in the case of ionospheric dusty plasmas. In this investigation, it is found that the growth rate of DA mode increases two orders more due to the photoelectric effect than that of the streaming effect. A detailed description of the dust charge fluctuation model in the irradiated dusty plasmas, the derivation of the DA mode, and discussions on the numerical analysis of the obtained results make the paper easy to understand. The present theory should be applied specially in understanding the formation of radar echoes in the presence of solar radiation.
{"title":"Instability of DA Mode in Ionospheric Dusty Plasmas","authors":"Md. Khairul Islam, Md. Sirajum Munir, Md. Afzal Hossain Talukder, M. A. Malek, Md. Salahuddin","doi":"10.1002/ctpp.202400123","DOIUrl":"https://doi.org/10.1002/ctpp.202400123","url":null,"abstract":"<div>\u0000 \u0000 <p>Irradiation effect on the different plasma modes in various dusty plasma conditions was studied theoretically. We revisit our investigation on the instability of the electrostatic dust acoustic (DA) mode elaborately in the case of ionospheric dusty plasmas. In this investigation, it is found that the growth rate of DA mode increases two orders more due to the photoelectric effect than that of the streaming effect. A detailed description of the dust charge fluctuation model in the irradiated dusty plasmas, the derivation of the DA mode, and discussions on the numerical analysis of the obtained results make the paper easy to understand. The present theory should be applied specially in understanding the formation of radar echoes in the presence of solar radiation.</p>\u0000 </div>","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"65 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315252","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}
Normalized vector potential (ay), the produced wakefield (Ex), the momentum (px) and the electron density (nx) for hydrogen atoms density/pre-ionized plasma density n0 = 0.01ncr at time 810 fs for the field-ionized plasma (panel a) and the pre-ionized plasma (panel b) and normalized vector potential variation a0 = 1 (in panels a1 and b1), a0 = 2 (in panels a2 and b2), and a0 = 3 (in panels a3 and b3). Fig. 4 of the paper by Elnaz Khalilzadeh et al. https://doi.org/10.1002/ctpp.202400022
{"title":"Cover Picture: Contrib. Plasma Phys. 02/2025","authors":"","doi":"10.1002/ctpp.202590003","DOIUrl":"https://doi.org/10.1002/ctpp.202590003","url":null,"abstract":"<p>Normalized vector potential (<i>a<sub>y</sub></i>), the produced wakefield (<i>E<sub>x</sub></i>), the momentum (<i>p<sub>x</sub></i>) and the electron density (<i>n<sub>x</sub></i>) for hydrogen atoms density/pre-ionized plasma density <i>n</i><sub>0</sub> = 0.01<i>n<sub>cr</sub></i> at time 810 fs for the field-ionized plasma (panel a) and the pre-ionized plasma (panel b) and normalized vector potential variation <i>a</i><sub>0</sub> = 1 (in panels a1 and b1), <i>a</i><sub>0</sub> = 2 (in panels a2 and b2), and <i>a</i><sub>0</sub> = 3 (in panels a3 and b3). Fig. 4 of the paper by Elnaz Khalilzadeh et al. https://doi.org/10.1002/ctpp.202400022\u0000 \u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"65 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ctpp.202590003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143431683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vivek Kumar Shukla, Saba Hussain, Monika Singh, Ram Kishor Singh
We have studied the circular polarised Terahertz (THz) wave emission by mixing of two lasers in plasma when an externally applied helical structured electric field is present. A nonlinear transverse current density at difference frequency emerges on the accounts of ponderomotive nonlinearity. This occurs when the electrons moving under the influence of externally applied helical electric field, couples with the nonlinear plasma density at difference frequency. This transverse current density can be decomposed of two mutually perpendicular vector having equal amplitude and phase shift, which drives a circular polarised coherent THz radiation. It turns out that conversion efficiency of THz radiation substantially depends on electron plasma frequency, mismatch phase, polarisation angle between laser beams and externally applied helical electric filed. Numerical simulations show that the conversion efficiency increases as THz frequency approach to plasma frequency.
本文研究了当外加螺旋结构电场存在时，等离子体中两束激光混合产生的圆极化太赫兹波发射。由于有源非线性，产生了差频下的非线性横向电流密度。当电子在外加螺旋电场的影响下运动，与非线性等离子体密度在差频下耦合时，就会发生这种现象。这种横向电流密度可以分解为两个相互垂直的矢量，具有相等的振幅和π / 2 $$ pi /2 $$相移，驱动圆偏振相干太赫兹辐射。结果表明，太赫兹辐射的转换效率在很大程度上取决于电子等离子体频率、错配相位、激光束与外加螺旋电场的极化角。数值模拟表明，太赫兹频率越接近等离子体频率，转换效率越高。
{"title":"Helical Electric Field-Assisted Circular Polarised Terahertz Wave Generation in Plasma by Beating of Two Lasers","authors":"Vivek Kumar Shukla, Saba Hussain, Monika Singh, Ram Kishor Singh","doi":"10.1002/ctpp.202400130","DOIUrl":"https://doi.org/10.1002/ctpp.202400130","url":null,"abstract":"<div>\u0000 \u0000 <p>We have studied the circular polarised Terahertz (THz) wave emission by mixing of two lasers in plasma when an externally applied helical structured electric field is present. A nonlinear transverse current density at difference frequency emerges on the accounts of ponderomotive nonlinearity. This occurs when the electrons moving under the influence of externally applied helical electric field, couples with the nonlinear plasma density at difference frequency. This transverse current density can be decomposed of two mutually perpendicular vector having equal amplitude and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>π</mi>\u0000 <mo>/</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 <annotation>$$ pi /2 $$</annotation>\u0000 </semantics></math> phase shift, which drives a circular polarised coherent THz radiation. It turns out that conversion efficiency of THz radiation substantially depends on electron plasma frequency, mismatch phase, polarisation angle between laser beams and externally applied helical electric filed. Numerical simulations show that the conversion efficiency increases as THz frequency approach to plasma frequency.</p>\u0000 </div>","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"65 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315129","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}
Dhyanjyoti D. Nath, Timothy R. Younkin, Jerome Guterl, Mark S. Shephard, Onkar Sahni
This paper presents the multi-species global impurity transport capability developed in a GPU-accelerated fully 3D unstructured mesh-based code, GITRm, to simultaneously track multiple impurity species and handle interactions of these impurities with mixed-material surfaces. Different computational approaches to model particle-surface interaction or surface response have been developed and compared. Sheath electric field is taken into account by employing a fast distance-to-boundary calculation, which is carried out in parallel on distributed or partitioned meshes on multiple GPUs without the need for any inter-process communication during the simulation. Several example cases, including two for the DIII-D tokamak, that is, one with the SAS-V divertor and the other with the collector probes, are used to demonstrate the utility of the current multi-species capability. For the DIII-D probe case, the capability of GITRm to resolve the spatial distribution of particles in localized regions, such as diagnostic probes, within non-axisymmetric tokamak geometries is demonstrated. These simulations involve up to 320 million particles and utilize up to 48 GPUs.
{"title":"A GPU-Accelerated 3D Unstructured Mesh Based Particle Tracking Code for Multi-Species Impurity Transport Simulation in Fusion Tokamaks","authors":"Dhyanjyoti D. Nath, Timothy R. Younkin, Jerome Guterl, Mark S. Shephard, Onkar Sahni","doi":"10.1002/ctpp.202400073","DOIUrl":"https://doi.org/10.1002/ctpp.202400073","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper presents the multi-species global impurity transport capability developed in a GPU-accelerated fully 3D unstructured mesh-based code, GITRm, to simultaneously track multiple impurity species and handle interactions of these impurities with mixed-material surfaces. Different computational approaches to model particle-surface interaction or surface response have been developed and compared. Sheath electric field is taken into account by employing a fast distance-to-boundary calculation, which is carried out in parallel on distributed or partitioned meshes on multiple GPUs without the need for any inter-process communication during the simulation. Several example cases, including two for the DIII-D tokamak, that is, one with the SAS-V divertor and the other with the collector probes, are used to demonstrate the utility of the current multi-species capability. For the DIII-D probe case, the capability of GITRm to resolve the spatial distribution of particles in localized regions, such as diagnostic probes, within non-axisymmetric tokamak geometries is demonstrated. These simulations involve up to 320 million particles and utilize up to 48 GPUs.</p>\u0000 </div>","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"65 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315447","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}
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