Di Peng, Qiaoshi Zeng, Fujun Lan, Zhenfang Xing, Yang Ding, Ho-kwang Mao
The recent report of superconductivity in nitrogen-doped lutetium hydride (Lu-H-N) at 294 K and 1 GPa brought hope for long-sought-after ambient-condition superconductors. However, the failure of scientists worldwide to independently reproduce these results has cast intense skepticism on this exciting claim. In this work, using a reliable experimental protocol, we synthesized Lu-H-N while minimizing extrinsic influences and reproduced the sudden change in resistance near room temperature. With quantitative comparison of the temperature-dependent resistance between Lu-H-N and the pure lutetium before reaction, we were able to clarify that the drastic resistance change is most likely caused by a metal-to-poor-conductor transition rather than by superconductivity. Herein, we also briefly discuss other issues recently raised in relation to the Lu-H-N system.
最近关于氮掺杂氢化镥(luu - h - n)在294 K和1 GPa下的超导性的报道为长期追求的环境条件超导体带来了希望。然而，世界各地的科学家都未能独立地重现这些结果，这让人们对这一令人兴奋的说法产生了强烈的怀疑。在这项工作中，我们使用可靠的实验方案，在最小化外部影响的情况下合成了Lu-H-N，并再现了室温附近电阻的突然变化。通过对反应前Lu-H-N和纯镥之间的温度相关电阻的定量比较，我们能够澄清，剧烈的电阻变化最有可能是由金属到贫导体的转变引起的，而不是由超导性引起的。在此，我们还简要讨论了最近提出的与Lu-H-N系统有关的其他问题。
{"title":"The near-room-temperature upsurge of electrical resistivity in Lu-H-N is not superconductivity, but a metal-to-poor-conductor transition","authors":"Di Peng, Qiaoshi Zeng, Fujun Lan, Zhenfang Xing, Yang Ding, Ho-kwang Mao","doi":"10.1063/5.0166430","DOIUrl":"https://doi.org/10.1063/5.0166430","url":null,"abstract":"The recent report of superconductivity in nitrogen-doped lutetium hydride (Lu-H-N) at 294 K and 1 GPa brought hope for long-sought-after ambient-condition superconductors. However, the failure of scientists worldwide to independently reproduce these results has cast intense skepticism on this exciting claim. In this work, using a reliable experimental protocol, we synthesized Lu-H-N while minimizing extrinsic influences and reproduced the sudden change in resistance near room temperature. With quantitative comparison of the temperature-dependent resistance between Lu-H-N and the pure lutetium before reaction, we were able to clarify that the drastic resistance change is most likely caused by a metal-to-poor-conductor transition rather than by superconductivity. Herein, we also briefly discuss other issues recently raised in relation to the Lu-H-N system.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134919896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
S. Kojima, T. Miyatake, H. Sakaki, Hiroyoshi Kuroki, Yusuke Shimizu, Hisanori Harada, N. Inoue, T. Dinh, M. Hata, N. Hasegawa, M. Mori, M. Ishino, M. Nishiuchi, K. Kondo, M. Nishikino, M. Kando, T. Shirai, K. Kondo
This study reports the first experimental demonstration of surface contamination cleaning from a high-repetition supply of thin-tape targets for laser-driven carbon-ion acceleration. The adsorption of contaminants containing protons, mainly water vapor and hydrocarbons, on the surface of materials exposed to low vacuum (>10−3 Pa) suppresses carbon-ion acceleration. The newly developed contamination cleaner heats a 5-μm-thick nickel tape to over 400 °C in 100 ms by induction heating. In the future, this heating method could be scaled to laser-driven carbon-ion acceleration at rates beyond 10 Hz. The contaminant hydrogen is eliminated from the heated nickel surface, and a carbon source layer—derived from the contaminant carbon—is spontaneously formed by the catalytic effect of nickel. The species of ions accelerated from the nickel film heated to various temperatures have been observed experimentally. When the nickel film is heated beyond ∼150 °C, the proton signal considerably decreases, with a remarkable increase in the number and energy of carbon ions. The Langmuir adsorption model adequately explains the temperature dependence of desorption and re-adsorption of the adsorbed molecules on a heated target surface, and the temperature required for proton-free carbon-ion acceleration can be estimated.
{"title":"Induction heating for desorption of surface contamination for high-repetition laser-driven carbon-ion acceleration","authors":"S. Kojima, T. Miyatake, H. Sakaki, Hiroyoshi Kuroki, Yusuke Shimizu, Hisanori Harada, N. Inoue, T. Dinh, M. Hata, N. Hasegawa, M. Mori, M. Ishino, M. Nishiuchi, K. Kondo, M. Nishikino, M. Kando, T. Shirai, K. Kondo","doi":"10.1063/5.0153578","DOIUrl":"https://doi.org/10.1063/5.0153578","url":null,"abstract":"This study reports the first experimental demonstration of surface contamination cleaning from a high-repetition supply of thin-tape targets for laser-driven carbon-ion acceleration. The adsorption of contaminants containing protons, mainly water vapor and hydrocarbons, on the surface of materials exposed to low vacuum (>10−3 Pa) suppresses carbon-ion acceleration. The newly developed contamination cleaner heats a 5-μm-thick nickel tape to over 400 °C in 100 ms by induction heating. In the future, this heating method could be scaled to laser-driven carbon-ion acceleration at rates beyond 10 Hz. The contaminant hydrogen is eliminated from the heated nickel surface, and a carbon source layer—derived from the contaminant carbon—is spontaneously formed by the catalytic effect of nickel. The species of ions accelerated from the nickel film heated to various temperatures have been observed experimentally. When the nickel film is heated beyond ∼150 °C, the proton signal considerably decreases, with a remarkable increase in the number and energy of carbon ions. The Langmuir adsorption model adequately explains the temperature dependence of desorption and re-adsorption of the adsorbed molecules on a heated target surface, and the temperature required for proton-free carbon-ion acceleration can be estimated.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"18 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87497109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Qian Wang, Zhi-chao Li, Zhanjun Liu, T. Gong, Wen-shuai Zhang, T. Xu, Bin Li, Ping Li, Xin Li, C. Zheng, L. Cao, Xincheng Liu, K. Pan, Hang Zhao, Yonggang Liu, B. Deng, Lifei Hou, Yingjie Li, Xiangming Liu, Yulong Li, X. Peng, Zanyang Guan, Qiangqiang Wang, X. Che, Sanwei Li, Qiang Yin, Wei Zhang, Liqiong Xia, Peng Wang, Xiaohua Jiang, Liang Guo, Qi Li, M. He, L. Hao, H. Cai, Wudi Zheng, S. Zou, Dong Yang, Feng Wang, Jiamin Yang, Bao-han Zhang, Yongkun Ding, Xiantu He
The first laser–plasma interaction experiment using lasers of eight beams grouped into one octad has been conducted on the Shenguang Octopus facility. Although each beam intensity is below its individual threshold for stimulated Brillouin backscattering (SBS), collective behaviors are excited to enhance the octad SBS. In particular, when two-color/cone lasers with wavelength separation 0.3 nm are used, the backward SBS reflectivities show novel behavior in which beams of longer wavelength achieve higher SBS gain. This property of SBS can be attributed to the rotation of the wave vectors of common ion acoustic waves due to the competition of detunings between geometrical angle and wavelength separation. This mechanism is confirmed using massively parallel supercomputer simulations with the three-dimensional laser–plasma interaction code LAP3D.
{"title":"The effects of incident light wavelength difference on the collective stimulated Brillouin scattering in plasmas","authors":"Qian Wang, Zhi-chao Li, Zhanjun Liu, T. Gong, Wen-shuai Zhang, T. Xu, Bin Li, Ping Li, Xin Li, C. Zheng, L. Cao, Xincheng Liu, K. Pan, Hang Zhao, Yonggang Liu, B. Deng, Lifei Hou, Yingjie Li, Xiangming Liu, Yulong Li, X. Peng, Zanyang Guan, Qiangqiang Wang, X. Che, Sanwei Li, Qiang Yin, Wei Zhang, Liqiong Xia, Peng Wang, Xiaohua Jiang, Liang Guo, Qi Li, M. He, L. Hao, H. Cai, Wudi Zheng, S. Zou, Dong Yang, Feng Wang, Jiamin Yang, Bao-han Zhang, Yongkun Ding, Xiantu He","doi":"10.1063/5.0151372","DOIUrl":"https://doi.org/10.1063/5.0151372","url":null,"abstract":"The first laser–plasma interaction experiment using lasers of eight beams grouped into one octad has been conducted on the Shenguang Octopus facility. Although each beam intensity is below its individual threshold for stimulated Brillouin backscattering (SBS), collective behaviors are excited to enhance the octad SBS. In particular, when two-color/cone lasers with wavelength separation 0.3 nm are used, the backward SBS reflectivities show novel behavior in which beams of longer wavelength achieve higher SBS gain. This property of SBS can be attributed to the rotation of the wave vectors of common ion acoustic waves due to the competition of detunings between geometrical angle and wavelength separation. This mechanism is confirmed using massively parallel supercomputer simulations with the three-dimensional laser–plasma interaction code LAP3D.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"107 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78090629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
T. Shelkovenko, I. N. Tilikin, A. Oginov, A. R. Mingaleev, V. Romanova, S. Pikuz
The results of a study of the electrical explosion of aluminum foils with an artificial periodic surface structure created by laser engraving are presented. Experiments were carried out on pulsed high-current generators BIN (270 kA, 300 kV, 100 ns) and KING (200 kA, 40 kV, 200 ns) with Al foil of thicknesses 16 and 4 μm, respectively. Images of the exploded foils were recorded by point projection radiography in the radiation from hybrid X-pinches. It is found that the application of an artificial periodic structure to the foil leads to a much more uniform and well-defined periodic structure of the exploded foil. Images recorded in the UV range using a microchannel-plate-intensified detector show that the radiation from a surface-modified foil is more uniform along the entire length and width of the foil than that from a foil without modification.
介绍了激光雕刻人工周期表面结构铝箔的电爆炸研究结果。实验采用厚度为16 μm和4 μm的Al箔，分别在脉冲大电流发生器BIN (270 kA, 300 kV, 100 ns)和KING (200 kA, 40 kV, 200 ns)上进行。爆炸箔的图像被记录在点投影射线摄影从混合x -掐的辐射。研究发现，在爆炸箔上应用人工周期结构可以使爆炸箔的周期结构更加均匀和明确。使用微通道板增强探测器在紫外范围内记录的图像表明，表面改性箔的辐射沿箔的整个长度和宽度比未改性箔的辐射更均匀。
{"title":"Methods of controlled formation of instabilities during the electrical explosion of thin foils","authors":"T. Shelkovenko, I. N. Tilikin, A. Oginov, A. R. Mingaleev, V. Romanova, S. Pikuz","doi":"10.1063/5.0146820","DOIUrl":"https://doi.org/10.1063/5.0146820","url":null,"abstract":"The results of a study of the electrical explosion of aluminum foils with an artificial periodic surface structure created by laser engraving are presented. Experiments were carried out on pulsed high-current generators BIN (270 kA, 300 kV, 100 ns) and KING (200 kA, 40 kV, 200 ns) with Al foil of thicknesses 16 and 4 μm, respectively. Images of the exploded foils were recorded by point projection radiography in the radiation from hybrid X-pinches. It is found that the application of an artificial periodic structure to the foil leads to a much more uniform and well-defined periodic structure of the exploded foil. Images recorded in the UV range using a microchannel-plate-intensified detector show that the radiation from a surface-modified foil is more uniform along the entire length and width of the foil than that from a foil without modification.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"10 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75192106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Charge-changing processes of low-charged ions, used in hydrogen plasma probing by the heavy ion beam probe method, are considered. Along with the ionization of beam ions by plasma electrons and protons, the charge-exchange processes of ions on H atoms and protons are also studied. It is shown that charge exchange of beam ions on plasma protons and H atoms, which is rarely taken into account, plays an important role in beam–plasma interaction. New data on the cross sections and rates of ionization and charge-exchange processes are presented for Tl+ and Tl2+ ions, which are frequently used for plasma diagnostics. Calculations are performed for hydrogen plasma temperatures Te = 1 eV–10 keV and densities Ne = 1012–1014 cm−3 at relatively low and high ion-beam velocities vb = 0.2 and 1.0 a.u., respectively. Special attention is paid to the determination of the electron temperatures at which the charge-exchange processes on H atoms and protons are important. Multiple ionization of beam ions by plasma electrons and protons is briefly discussed.
{"title":"The role of charge-exchange processes in probing hydrogen plasma with a heavy ion beam","authors":"I. Tolstikhina, V. P. Shevelko","doi":"10.1063/5.0157170","DOIUrl":"https://doi.org/10.1063/5.0157170","url":null,"abstract":"Charge-changing processes of low-charged ions, used in hydrogen plasma probing by the heavy ion beam probe method, are considered. Along with the ionization of beam ions by plasma electrons and protons, the charge-exchange processes of ions on H atoms and protons are also studied. It is shown that charge exchange of beam ions on plasma protons and H atoms, which is rarely taken into account, plays an important role in beam–plasma interaction. New data on the cross sections and rates of ionization and charge-exchange processes are presented for Tl+ and Tl2+ ions, which are frequently used for plasma diagnostics. Calculations are performed for hydrogen plasma temperatures Te = 1 eV–10 keV and densities Ne = 1012–1014 cm−3 at relatively low and high ion-beam velocities vb = 0.2 and 1.0 a.u., respectively. Special attention is paid to the determination of the electron temperatures at which the charge-exchange processes on H atoms and protons are important. Multiple ionization of beam ions by plasma electrons and protons is briefly discussed.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"11 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86648032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
R. Rossi, M. Gelfusa, T. Craciunescu, L. Spolladore, I. Wyss, E. Peluso, J. Vega, C. Maggi, J. Mailloux, M. Maslov, A. Murari
To produce fusion reactions efficiently, thermonuclear plasmas have to reach extremely high temperatures, which is incompatible with their coming into contact with material surfaces. Confinement of plasmas using magnetic fields has progressed significantly in the last years, particularly in the tokamak configuration. Unfortunately, all tokamak devices, and particularly metallic ones, are plagued by catastrophic events called disruptions. Many disruptions are preceded by anomalies in the radiation patterns, particularly in ITER-relevant scenarios. These specific forms of radiation emission either directly cause or reveal the approaching collapse of the configuration. Detecting the localization of these radiation anomalies in real time requires an innovative and specific elaboration of bolometric measurements, confirmed by visible cameras and the inversion of sophisticated tomographic algorithms. The information derived from these measurements can be interpreted in terms of local power balances, which suggest a new quantity, the radiated power divided by the plasma internal energy, to determine the criticality of the plasma state. Combined with robust indicators of the temperature profile shape, the identified anomalous radiation patterns allow determination of the sequence of macroscopic events leading to disruptions. A systematic analysis of JET campaigns at high power in deuterium, full tritium, and DT, for a total of almost 2000 discharges, proves the effectiveness of the approach. The warning times are such that, depending on the radiation anomaly and the available actuators, the control system of future devices is expected to provide enough notice to enable deployment of effective prevention and avoidance strategies.
{"title":"A systematic investigation of radiation collapse for disruption avoidance and prevention on JET tokamak","authors":"R. Rossi, M. Gelfusa, T. Craciunescu, L. Spolladore, I. Wyss, E. Peluso, J. Vega, C. Maggi, J. Mailloux, M. Maslov, A. Murari","doi":"10.1063/5.0143193","DOIUrl":"https://doi.org/10.1063/5.0143193","url":null,"abstract":"To produce fusion reactions efficiently, thermonuclear plasmas have to reach extremely high temperatures, which is incompatible with their coming into contact with material surfaces. Confinement of plasmas using magnetic fields has progressed significantly in the last years, particularly in the tokamak configuration. Unfortunately, all tokamak devices, and particularly metallic ones, are plagued by catastrophic events called disruptions. Many disruptions are preceded by anomalies in the radiation patterns, particularly in ITER-relevant scenarios. These specific forms of radiation emission either directly cause or reveal the approaching collapse of the configuration. Detecting the localization of these radiation anomalies in real time requires an innovative and specific elaboration of bolometric measurements, confirmed by visible cameras and the inversion of sophisticated tomographic algorithms. The information derived from these measurements can be interpreted in terms of local power balances, which suggest a new quantity, the radiated power divided by the plasma internal energy, to determine the criticality of the plasma state. Combined with robust indicators of the temperature profile shape, the identified anomalous radiation patterns allow determination of the sequence of macroscopic events leading to disruptions. A systematic analysis of JET campaigns at high power in deuterium, full tritium, and DT, for a total of almost 2000 discharges, proves the effectiveness of the approach. The warning times are such that, depending on the radiation anomaly and the available actuators, the control system of future devices is expected to provide enough notice to enable deployment of effective prevention and avoidance strategies.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"43 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85418959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Feng Chen, Haibo Xu, Junhui Shi, Xinge Li, Na Zheng
Diagnosis of fluids is extremely significant at high temperatures and high pressures. As an advanced imaging technique, high-energy proton radiography has great potential for application to the diagnosis of high-density fluids. In high-energy proton radiography, an angular collimator can control the proton flux and thus enable material diagnosis and reconstruction of density. In this paper, we propose a multi-material diagnostic method using angular collimators. The method is verified by reconstructing the density distribution from the proton flux obtained via theoretical calculations and numerical simulations. We simulate a 20 GeV proton imaging system using the Geant4 software toolkit and obtain the characteristic parameters of single-material objects. We design several concentric spherical objects to verify the method. We discuss its application to detonation tests. The results show that this method can determine the material and boundary information about each component of a multi-material object. Thus, it can be used to diagnose a mixed material and reconstruct densities in a detonation.
{"title":"A multi-material diagnosis method based on high-energy proton radiography","authors":"Feng Chen, Haibo Xu, Junhui Shi, Xinge Li, Na Zheng","doi":"10.1063/5.0138725","DOIUrl":"https://doi.org/10.1063/5.0138725","url":null,"abstract":"Diagnosis of fluids is extremely significant at high temperatures and high pressures. As an advanced imaging technique, high-energy proton radiography has great potential for application to the diagnosis of high-density fluids. In high-energy proton radiography, an angular collimator can control the proton flux and thus enable material diagnosis and reconstruction of density. In this paper, we propose a multi-material diagnostic method using angular collimators. The method is verified by reconstructing the density distribution from the proton flux obtained via theoretical calculations and numerical simulations. We simulate a 20 GeV proton imaging system using the Geant4 software toolkit and obtain the characteristic parameters of single-material objects. We design several concentric spherical objects to verify the method. We discuss its application to detonation tests. The results show that this method can determine the material and boundary information about each component of a multi-material object. Thus, it can be used to diagnose a mixed material and reconstruct densities in a detonation.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"1 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75201053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Dongdi Zhao, Yongpeng Zhao, Bo An, Jiaqi Li, H. Cui
Using a plane–plane resonator composed of silicon carbide mirrors, we achieve for the first time multi-pass amplification of a 46.9 nm laser pumped by capillary discharge. In terms of the temporal characteristics, for an initial argon pressure of 17 Pa, triple-pass amplification of the laser is obtained at a delay time between the pre-pulse and the main pulse currents of 40 µs, and quadruple-pass amplification is obtained at a delay time of 50 µs. The experimental results show that the gain duration of the plasma column is more than 6 ns. In terms of spatial characteristics, the spot of the output laser has a reduced full width at half maximum divergence compared with that from a laser without a resonator.
{"title":"Demonstration of multi-pass amplification of 46.9 nm laser pumped by capillary discharge","authors":"Dongdi Zhao, Yongpeng Zhao, Bo An, Jiaqi Li, H. Cui","doi":"10.1063/5.0150165","DOIUrl":"https://doi.org/10.1063/5.0150165","url":null,"abstract":"Using a plane–plane resonator composed of silicon carbide mirrors, we achieve for the first time multi-pass amplification of a 46.9 nm laser pumped by capillary discharge. In terms of the temporal characteristics, for an initial argon pressure of 17 Pa, triple-pass amplification of the laser is obtained at a delay time between the pre-pulse and the main pulse currents of 40 µs, and quadruple-pass amplification is obtained at a delay time of 50 µs. The experimental results show that the gain duration of the plasma column is more than 6 ns. In terms of spatial characteristics, the spot of the output laser has a reduced full width at half maximum divergence compared with that from a laser without a resonator.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"1 2","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72608663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
L. Burakovsky, D. Preston, S. Ramsey, C. Starrett, R. Baty
Although they are polymorphic (multiphase) materials, both copper and silver are reliable Hugoniot standards, and thus it is necessary to establish an accurate analytic model of their principal Hugoniots. Here we present analytic forms of their principal Hugoniots, as well as those of iridium and platinum, two “pusher” standards for shock-ramp experiments, over a wide range of pressures. They are based on our new analytic model of the principal Hugoniot [Burakovsky et al., J. Appl. Phys. 132, 215109 (2022)]. Comparison of the four Hugoniots with experimental and independent theoretical data (such data exist to very high pressures for both copper and silver) demonstrates excellent agreement. Hence, the new model for copper and silver can be considered as providing the corresponding Hugoniot standards over a wide pressure range. We also suggest an approach for calculating the Grüneisen parameter along the Hugoniot and apply it to copper as a prototype, and our results appear to be in good agreement with the available data.
虽然铜和银都是多晶(多相)材料，但它们都是可靠的Hugoniot标准，因此有必要建立其主Hugoniot的精确解析模型。在这里，我们给出了他们的主要Hugoniots的解析形式，以及铱和铂的解析形式，这是两个用于冲击斜坡实验的“推手”标准，在很宽的压力范围内。它们是基于我们的主要Hugoniot的新分析模型[Burakovsky et al.， J. appll]。物理学报，2002,22(2):559 - 564。将四个Hugoniots与实验数据和独立理论数据(铜和银都存在非常高的压力)进行比较，证明了非常好的一致性。因此，铜和银的新模型可以被认为是在很宽的压力范围内提供相应的Hugoniot标准。我们还提出了一种沿Hugoniot计算grisen参数的方法，并将其应用于铜作为原型，我们的结果似乎与现有数据很好地一致。
{"title":"Shock standards Cu, Ag, Ir, and Pt in a wide pressure range","authors":"L. Burakovsky, D. Preston, S. Ramsey, C. Starrett, R. Baty","doi":"10.1063/5.0124555","DOIUrl":"https://doi.org/10.1063/5.0124555","url":null,"abstract":"Although they are polymorphic (multiphase) materials, both copper and silver are reliable Hugoniot standards, and thus it is necessary to establish an accurate analytic model of their principal Hugoniots. Here we present analytic forms of their principal Hugoniots, as well as those of iridium and platinum, two “pusher” standards for shock-ramp experiments, over a wide range of pressures. They are based on our new analytic model of the principal Hugoniot [Burakovsky et al., J. Appl. Phys. 132, 215109 (2022)]. Comparison of the four Hugoniots with experimental and independent theoretical data (such data exist to very high pressures for both copper and silver) demonstrates excellent agreement. Hence, the new model for copper and silver can be considered as providing the corresponding Hugoniot standards over a wide pressure range. We also suggest an approach for calculating the Grüneisen parameter along the Hugoniot and apply it to copper as a prototype, and our results appear to be in good agreement with the available data.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"40 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84122842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
A novel experimental method is proposed for observing plasma dynamics subjected to magnetic fields based on a newly developed cylindrical theta-pinch device. By measuring simultaneously the temporal profiles of multiple parameters including the drive current, luminosity, plasma density, and plasma temperature, it provides a basis for observing the plasma dynamics of the theta pinch, such as shock transport and magnetohydrodynamic instability. We show that the plasma evolution can be distinguished as three phases. First, in the radial implosion phase, the trajectories of the current sheath and shock wave are ascertained by combining experimental data with a snowplow model (Lee model) in a self-consistent way. Second, in the axial flow phase, we demonstrate that m = 0 (sausage) instability associated with the plasma axial flow suppresses the plasma end-loss. Third, in the newly observed anomalous heating phase, the lower-hybrid-drift instability may develop near the current sheath, which induces anomalous resistivity and enhanced plasma heating. The present experimental data and novel method offer better understanding of plasma dynamics in the presence of magnetic fields, thereby providing important support for relevant research in magneto-inertial fusion.
{"title":"Observation of plasma dynamics in a theta pinch by a novel method","authors":"Zhao Wang, Rui Cheng, Guodong Wang, Xuejian Jin, Yong Tang, Yanhong Chen, Zexian Zhou, Lulin Shi, Yuyu Wang, Y. Lei, Xiaoxia Wu, Junliang Yang","doi":"10.1063/5.0144921","DOIUrl":"https://doi.org/10.1063/5.0144921","url":null,"abstract":"A novel experimental method is proposed for observing plasma dynamics subjected to magnetic fields based on a newly developed cylindrical theta-pinch device. By measuring simultaneously the temporal profiles of multiple parameters including the drive current, luminosity, plasma density, and plasma temperature, it provides a basis for observing the plasma dynamics of the theta pinch, such as shock transport and magnetohydrodynamic instability. We show that the plasma evolution can be distinguished as three phases. First, in the radial implosion phase, the trajectories of the current sheath and shock wave are ascertained by combining experimental data with a snowplow model (Lee model) in a self-consistent way. Second, in the axial flow phase, we demonstrate that m = 0 (sausage) instability associated with the plasma axial flow suppresses the plasma end-loss. Third, in the newly observed anomalous heating phase, the lower-hybrid-drift instability may develop near the current sheath, which induces anomalous resistivity and enhanced plasma heating. The present experimental data and novel method offer better understanding of plasma dynamics in the presence of magnetic fields, thereby providing important support for relevant research in magneto-inertial fusion.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"104 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80770315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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