High Energy Density Physics最新文献

{"title":"High-precision room temperature Fe opacity measurements at 1000-2000eV photon energies","authors":"Malia L. Kao ,&nbsp;Guillaume P. Loisel ,&nbsp;James E. Bailey ,&nbsp;Patrick W. Lake ,&nbsp;Paul D. Gard ,&nbsp;Gregory A. Rochau ,&nbsp;George R. Burns ,&nbsp;William R. Wampler ,&nbsp;Haibo Huang ,&nbsp;Michael N. Weir","doi":"10.1016/j.hedp.2023.101064","DOIUrl":"10.1016/j.hedp.2023.101064","url":null,"abstract":"<div><p>Prior measurements of room temperature (cold) Fe opacity have errors as high as <em>±</em>10 % and a spread in values that exceeds the uncertainties. These data, along with current cold opacity databases, were used for comparison with experimental solar Fe opacity. The solar Fe opacity is expected to be lower than cold Fe opacity in the <em>∼</em>1500–2000 eV photon energy range. However, results from this comparison contradicted this assumption and prompted an investigation of the precision and accuracy of cold Fe opacity measurements. Cold Fe opacity is determined here with high precision using transmission measurements of Fe foils at three characteristic line energies in the soft X-ray range (1000–2000 eV). The present opacities are determined with ≲1 % overall uncertainties. This is achieved through precise measurements of transmission and areal density which are related to opacity by the Beer-Lambert Law. Transmission is measured with overall individual uncertainties of ≲1 % and is obtained through simultaneous measurements of attenuated and unattenuated spectra using an X-ray source and a Bragg crystal spectrometer. The required areal density is indepen-dently measured using two different techniques: Rutherford Backscattering Spectroscopy and a recently-developed technique using calibrated cold absorption in the 3–17 keV range. The final areal density used in the opacity determination is an average between both methods. The measured opacity at 1188 eV is in agreement with current opacity databases but is higher by around 5–10 % at the highest photon energy (1924 eV) and lower by around 2–4 % at the lowest photon energy (1012 eV). A caveat is that opacity accuracy is linearly dependent on the areal density. We performed the first direct comparison between the two areal density methods which revealed a 7–11 % discrepancy. If one of the methods is proven correct in future studies, it may impact the opacity accuracy reported here since we use the average of the two methods. This result affects the solar Fe opacity measurements as they also rely on the accuracy of these areal density measurement techniques.</p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"49 ","pages":"Article 101064"},"PeriodicalIF":1.6,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1574181823000307/pdfft?md5=985ad748bad3faeb094a9e63ef90556d&pid=1-s2.0-S1574181823000307-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135705867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Simulation of dissociation effect at high temperature and high pressure by REMC method","authors":"Mingrui Li ,&nbsp;Na Feng ,&nbsp;Pengfei Gao ,&nbsp;Gang Zhou ,&nbsp;Chunlin Chen ,&nbsp;Bingwen Qian","doi":"10.1016/j.hedp.2023.101068","DOIUrl":"10.1016/j.hedp.2023.101068","url":null,"abstract":"<div><p>Considering the zero-point vibration energy of fluid H₂, the dissociation process of fluid H₂ at different temperatures and densities under 10000 K was studied by using the REMC (reaction ensemble Monte Carlo) method based on classical theory, and the results of different methods were compared and analyzed. The variation of the dissociation degree with temperature predicted by the REMC method is similar to that of the DM method, and the value of the dissociation degree is closest to that of the TB-II method. The dissociation degree of fluid H₂ is less than 38% at 10000 K. According to this REMC method, the fluid D₂ begins to dissociate when the shock pressure reaches 20 GPa. When the shock pressure is 50 GPa, the dissociation degree is 23.88%; At 100 GPa, the dissociation degree is 61.30%. The calculated dissociation value of fluid D₂<span> is lower than that of the QMD method under high temperature and high pressure, while it is in good agreement with the experimental results derived from light gas gun under low temperature and low pressure.</span></p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"49 ","pages":"Article 101068"},"PeriodicalIF":1.6,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135656069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Fast approximation to supershell partition functions: Explicit forms of the coefficients","authors":"Jean-Christophe Pain ,&nbsp;Brian G. Wilson","doi":"10.1016/j.hedp.2023.101065","DOIUrl":"10.1016/j.hedp.2023.101065","url":null,"abstract":"<div><p>In a previous work, we derived a formula for supershell partition functions, which are the cornerstone of the Super-Transition-Array approach to radiative-opacity calculations. The new expression takes the form of a functional of the distribution of energies within the supershell and allows for fast and accurate computations, truncating the number of terms in the expansion. The latter involves coefficients (denoted <span><math><msub><mrow><mi>Γ</mi></mrow><mrow><mi>k</mi></mrow></msub></math></span>) for which we obtained a recursion relation. In the present short paper, as a complement of the previous one, we give an explicit formula for the coefficients <span><math><msub><mrow><mi>Γ</mi></mrow><mrow><mi>k</mi></mrow></msub></math></span>. Another recursion relation is also provided, as well as an alternative expression involving Bell polynomials. The connections with cycle indexes of permutation groups and with elementary symmetric polynomials are outlined.</p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"49 ","pages":"Article 101065"},"PeriodicalIF":1.6,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135660807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Stimulated Raman side and backscatter instabilities of crossed laser beams in plasma","authors":"Vijay Singh ,&nbsp;Benatus Norbert Mvile ,&nbsp;Anoop Kumar Pandey","doi":"10.1016/j.hedp.2023.101054","DOIUrl":"10.1016/j.hedp.2023.101054","url":null,"abstract":"<div><p><span>Stimulated Raman scattering (SRS) instability due to two nonlinearly coupled </span>laser beams<span> propagating in homogeneous, thermal plasma is analyzed. The temporal evolution equations for pump, scattered and Langmuir waves excited due to the interaction are set up. Using numerical techniques temporal evolution of amplitudes of pump, scattered and resultant Langmuir waves for side and back SRS instabilities have been obtained in the non-relativistic regime. The temporal growth rate, saturation time and saturation amplitude of waves excited by two crossed (perpendicular) lasers are studied and compared with the single beam case. The model considers pump depletion to be the dominant saturation mechanism. The study points towards a new concept for generation of high amplitude Langmuir waves.</span></p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"48 ","pages":"Article 101054"},"PeriodicalIF":1.6,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49172377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"SpK: A fast atomic and microphysics code for the high-energy-density regime","authors":"A.J. Crilly ,&nbsp;N.P.L. Niasse ,&nbsp;A.R. Fraser ,&nbsp;D.A. Chapman ,&nbsp;K.W. McLean ,&nbsp;S.J. Rose ,&nbsp;J.P. Chittenden","doi":"10.1016/j.hedp.2023.101053","DOIUrl":"10.1016/j.hedp.2023.101053","url":null,"abstract":"<div><p>SpK is part of the numerical codebase at Imperial College London used to model high energy density physics (HEDP) experiments. SpK is an efficient atomic and microphysics code used to perform detailed configuration accounting calculations of electronic and ionic stage populations, opacities and emissivities for use in post-processing and radiation hydrodynamics simulations. This is done using screened hydrogenic atomic data supplemented by the NIST energy level database. An extended Saha model solves for chemical equilibrium with extensions for non-ideal physics, such as ionisation potential depression, and non thermal equilibrium corrections. A tree-heap (treap) data structure is used to store spectral data, such as opacity, which is dynamic thus allowing easy insertion of points around spectral lines without a-priori knowledge of the ion stage populations. Results from SpK are compared to other codes and descriptions of radiation transport solutions which use SpK data are given. The treap data structure and SpK’s computational efficiency allows inline post-processing of 3D hydrodynamics simulations with a dynamically evolving spectrum stored in a treap.</p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"48 ","pages":"Article 101053"},"PeriodicalIF":1.6,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42070590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"On the transient spatial localization model","authors":"Carlos A. Iglesias","doi":"10.1016/j.hedp.2023.101043","DOIUrl":"10.1016/j.hedp.2023.101043","url":null,"abstract":"<div><p><span>Significant discrepancies relevant to helioseismology<span> between experimental and theoretical photon absorption by plasmas remain unresolved. Interestingly, a new process called transient spatial localization (TSL), where the plasma perturbs the final states in photon ionization processes, ostensibly enhances cross-sections resolving the extant discrepancies. The TSL model, however, is shown to involve </span></span><em>ad hoc</em> formulas not derived from fundamental principles and systematic approximations. In addition, a variant of the TSL model, which claimed to enhance electron collisional ionization, is inconsistent with the Schrodinger equation and fails to reproduce known results.</p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"47 ","pages":"Article 101043"},"PeriodicalIF":1.6,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41452291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Schrödinger equation on a generic radial grid","authors":"Christopher Bowen ,&nbsp;Jean-Christophe Pain","doi":"10.1016/j.hedp.2023.101042","DOIUrl":"10.1016/j.hedp.2023.101042","url":null,"abstract":"<div><p>In this note, we discuss the choice of radial grid in the numerical resolution of the Schrödinger equation. We detail the transformation of the equation resulting from a change of variable and function for a generic radial grid, using either the explicit or implicit form of the relation describing the change of variable, and apply it to the <span><math><mrow><mi>a</mi><mspace></mspace><mi>r</mi><mo>+</mo><mi>b</mi><mspace></mspace><mo>ln</mo><mrow><mo>(</mo><mi>r</mi><mo>)</mo></mrow></mrow></math></span> log-linear mesh. It is shown that, in the former case, the first three derivatives of the Lambert <span><math><mi>W</mi></math></span> function are required. This complication becomes unnecessary if we adopt the implicit relation instead.</p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"47 ","pages":"Article 101042"},"PeriodicalIF":1.6,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41475971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Atomic structure considerations for the low-temperature opacity of Xenon","authors":"A.J. Neukirch,&nbsp;J. Colgan","doi":"10.1016/j.hedp.2022.101034","DOIUrl":"https://doi.org/10.1016/j.hedp.2022.101034","url":null,"abstract":"<div><p>We have begun a preliminary investigation into the opacity of Xe at low temperatures (&lt;50 eV). The emissivity and opacity of Xe is a crucial factor in determining the utility of Xe in EUV lithography, with numerous industrial applications. To this end, we have been exploring the accuracy of some approximations used in opacity models for the relevant ion stages of Xe (6 times ionized through 20 times ionized). Due to the complexity of Xe atomic structure, one needs to use full configuration-interaction to properly describe the strong mixing in the various n=4 sub-shells that give rise to the Δn=0 and Δn=1 transitions that dominate the opacity spectrum at low temperatures. Since calculations that include full configuration-interaction for large numbers of configurations quickly become computationally prohibitive, we have explored hybrid calculations, in which full configuration-interaction is retained for the most important transitions, while intermediate coupling is employed for all other transitions. After verifying atomic structure properties, local-thermodynamic-equilibrium (LTE) opacities are generated using the ATOMIC code at selected temperatures and densities and compared to various experimental results.</p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"46 ","pages":"Article 101034"},"PeriodicalIF":1.6,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49864908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Screening and relativistic effects on the stark broadening of hydrogenic ion lines in a plasma","authors":"D.E. Zenkhri,&nbsp;M.T. Meftah,&nbsp;F. Khelfaoui","doi":"10.1016/j.hedp.2023.101035","DOIUrl":"https://doi.org/10.1016/j.hedp.2023.101035","url":null,"abstract":"<div><p><span>In the present work, we compute the amplitude of the real part of the electronic collision operator for the electron broadening of hydrogenic ion lines in plasmas, taking into account the screening effects (the interaction between the free electron (perturber) and the ion (emitter) is governed by Debye potential) and </span>relativistic effects in the dynamics of the perturbing electron. The screening effects are included using the cross section calculated by Debye potential instead of Rutherford cross section and the relativistic effects are included by the modification of the velocity distribution (Maxwell–Jûttner) instead of (Maxwell–Boltzmann) distribution and relativistic mass (mass depend on the velocity). The obtained results are compared with Griem’s theoretical work.</p></div>","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"46 ","pages":"Article 101035"},"PeriodicalIF":1.6,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49864909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Screening and relativistic effects on the stark broadening of hydrogenic ion lines in a plasma","authors":"D. E. Zenkhri, M. T. Meftah, F. Khelfaoui","doi":"10.1016/j.hedp.2023.101035","DOIUrl":"https://doi.org/10.1016/j.hedp.2023.101035","url":null,"abstract":"","PeriodicalId":49267,"journal":{"name":"High Energy Density Physics","volume":"70 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54448265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}