Pub Date : 2024-09-18DOI: 10.1017/s0022377824000783
Tao Zeng, Nan Li, Yuliang Yi
The femtosecond laser filament-induced air laser plays a significant role for the remote sensing of air pollutants. The spatial distributions of air laser intensity were investigated experimentally in previous studies. However, the mechanism of the air laser propagation properties inside the filament plasma has not been quite clear yet. Moreover, few studies have been dedicated to the reproduction of the air laser profile from nitrogen molecules propagating in the filament plasma based on the numerical simulation method. In this study, the lasing action of the air laser from the transition of the first negative (0,0) band of nitrogen ions at 391 nm was simulated during the femtosecond laser filamentation. The beam profile of the air laser changes from a Gaussian or super-Gaussian shape to an outer ring structure by increasing the filament length or nitrogen ion density, which is in accord with the previous experimental result. A multiple-diffraction effect has been proposed to clarify the mechanism of the outer rings beam pattern formation, which is induced by the dynamical interaction between the lasing effect and diffraction effect of the air laser propagating inside the filament plasma. In addition, the amplified air laser power as a function of both the filament length and nitrogen ion density was investigated. Our study would pave the way to improve the energy conversion efficiency and directivity of remote air lasers, which would be significant for remote sensing applications.
{"title":"Spatial distribution of self-seeded air lasers induced by the femtosecond laser filament plasma","authors":"Tao Zeng, Nan Li, Yuliang Yi","doi":"10.1017/s0022377824000783","DOIUrl":"https://doi.org/10.1017/s0022377824000783","url":null,"abstract":"The femtosecond laser filament-induced air laser plays a significant role for the remote sensing of air pollutants. The spatial distributions of air laser intensity were investigated experimentally in previous studies. However, the mechanism of the air laser propagation properties inside the filament plasma has not been quite clear yet. Moreover, few studies have been dedicated to the reproduction of the air laser profile from nitrogen molecules propagating in the filament plasma based on the numerical simulation method. In this study, the lasing action of the air laser from the transition of the first negative (0,0) band of nitrogen ions at 391 nm was simulated during the femtosecond laser filamentation. The beam profile of the air laser changes from a Gaussian or super-Gaussian shape to an outer ring structure by increasing the filament length or nitrogen ion density, which is in accord with the previous experimental result. A multiple-diffraction effect has been proposed to clarify the mechanism of the outer rings beam pattern formation, which is induced by the dynamical interaction between the lasing effect and diffraction effect of the air laser propagating inside the filament plasma. In addition, the amplified air laser power as a function of both the filament length and nitrogen ion density was investigated. Our study would pave the way to improve the energy conversion efficiency and directivity of remote air lasers, which would be significant for remote sensing applications.","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"69 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142266460","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}
Pub Date : 2024-09-18DOI: 10.1017/s0022377824000795
I. Novikau, I.Y. Dodin, E.A. Startsev
We propose an algorithm for encoding linear kinetic plasma problems in quantum circuits. The focus is on modelling electrostatic linear waves in a one-dimensional Maxwellian electron plasma. The waves are described by the linearized Vlasov–Ampère system with a spatially localized external current that drives plasma oscillations. This system is formulated as a boundary-value problem and cast in the form of a linear vector equation $boldsymbol {A}{boldsymbol{psi} } = boldsymbol {b}$ to be solved by using the quantum signal processing algorithm. The latter requires encoding of matrix $boldsymbol {A}$ in a quantum circuit as a sub-block of a unitary matrix. We propose how to encode $boldsymbol {A}$ in a circuit in a compressed form and discuss how the resulting circuit scales with the problem size and the desired precision.
{"title":"Encoding of linear kinetic plasma problems in quantum circuits via data compression","authors":"I. Novikau, I.Y. Dodin, E.A. Startsev","doi":"10.1017/s0022377824000795","DOIUrl":"https://doi.org/10.1017/s0022377824000795","url":null,"abstract":"We propose an algorithm for encoding linear kinetic plasma problems in quantum circuits. The focus is on modelling electrostatic linear waves in a one-dimensional Maxwellian electron plasma. The waves are described by the linearized Vlasov–Ampère system with a spatially localized external current that drives plasma oscillations. This system is formulated as a boundary-value problem and cast in the form of a linear vector equation <jats:inline-formula> <jats:alternatives> <jats:tex-math>$boldsymbol {A}{boldsymbol{psi} } = boldsymbol {b}$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000795_inline1.png\"/> </jats:alternatives> </jats:inline-formula> to be solved by using the quantum signal processing algorithm. The latter requires encoding of matrix <jats:inline-formula> <jats:alternatives> <jats:tex-math>$boldsymbol {A}$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000795_inline2.png\"/> </jats:alternatives> </jats:inline-formula> in a quantum circuit as a sub-block of a unitary matrix. We propose how to encode <jats:inline-formula> <jats:alternatives> <jats:tex-math>$boldsymbol {A}$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000795_inline3.png\"/> </jats:alternatives> </jats:inline-formula> in a circuit in a compressed form and discuss how the resulting circuit scales with the problem size and the desired precision.","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"21 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142266723","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}
Pub Date : 2024-09-18DOI: 10.1017/s0022377824000503
Erika Ye, Nuno F. Loureiro
The Vlasov–Maxwell equations provide an <jats:italic>ab initio</jats:italic> description of collisionless plasmas, but solving them is often impractical because of the wide range of spatial and temporal scales that must be resolved and the high dimensionality of the problem. In this work, we present a quantum-inspired semi-implicit Vlasov–Maxwell solver that uses the quantized tensor network (QTN) framework. With this QTN solver, the cost of grid-based numerical simulation of size <jats:inline-formula> <jats:alternatives> <jats:tex-math>$N$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000503_inline1.png"/> </jats:alternatives> </jats:inline-formula> is reduced from <jats:inline-formula> <jats:alternatives> <jats:tex-math>$O(N)$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000503_inline2.png"/> </jats:alternatives> </jats:inline-formula> to <jats:inline-formula> <jats:alternatives> <jats:tex-math>$O(text {poly}(D))$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000503_inline3.png"/> </jats:alternatives> </jats:inline-formula>, where <jats:inline-formula> <jats:alternatives> <jats:tex-math>$D$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000503_inline4.png"/> </jats:alternatives> </jats:inline-formula> is the ‘rank’ or ‘bond dimension’ of the QTN and is typically set to be much smaller than <jats:inline-formula> <jats:alternatives> <jats:tex-math>$N$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000503_inline5.png"/> </jats:alternatives> </jats:inline-formula>. We find that for the five-dimensional test problems considered here, a modest <jats:inline-formula> <jats:alternatives> <jats:tex-math>$D=64$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000503_inline6.png"/> </jats:alternatives> </jats:inline-formula> appears to be sufficient for capturing the expected physics despite the simulations using a total of <jats:inline-formula> <jats:alternatives> <jats:tex-math>$N=2^{36}$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000503_inline7.png"/> </jats:alternatives> </jats:inline-formula> grid points, which would require <jats:inline-formula> <jats:alternatives> <jats:tex-math>$D=2^{18}$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000503_inline8.png"/> </jats:alternatives> </jats:inline-formula> for full-rank calculations. Additionally, we observe that a QTN time evolution scheme based on the Dirac–Frenkel variational principle allows one to use some
{"title":"Quantized tensor networks for solving the Vlasov–Maxwell equations","authors":"Erika Ye, Nuno F. Loureiro","doi":"10.1017/s0022377824000503","DOIUrl":"https://doi.org/10.1017/s0022377824000503","url":null,"abstract":"The Vlasov–Maxwell equations provide an <jats:italic>ab initio</jats:italic> description of collisionless plasmas, but solving them is often impractical because of the wide range of spatial and temporal scales that must be resolved and the high dimensionality of the problem. In this work, we present a quantum-inspired semi-implicit Vlasov–Maxwell solver that uses the quantized tensor network (QTN) framework. With this QTN solver, the cost of grid-based numerical simulation of size <jats:inline-formula> <jats:alternatives> <jats:tex-math>$N$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000503_inline1.png\"/> </jats:alternatives> </jats:inline-formula> is reduced from <jats:inline-formula> <jats:alternatives> <jats:tex-math>$O(N)$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000503_inline2.png\"/> </jats:alternatives> </jats:inline-formula> to <jats:inline-formula> <jats:alternatives> <jats:tex-math>$O(text {poly}(D))$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000503_inline3.png\"/> </jats:alternatives> </jats:inline-formula>, where <jats:inline-formula> <jats:alternatives> <jats:tex-math>$D$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000503_inline4.png\"/> </jats:alternatives> </jats:inline-formula> is the ‘rank’ or ‘bond dimension’ of the QTN and is typically set to be much smaller than <jats:inline-formula> <jats:alternatives> <jats:tex-math>$N$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000503_inline5.png\"/> </jats:alternatives> </jats:inline-formula>. We find that for the five-dimensional test problems considered here, a modest <jats:inline-formula> <jats:alternatives> <jats:tex-math>$D=64$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000503_inline6.png\"/> </jats:alternatives> </jats:inline-formula> appears to be sufficient for capturing the expected physics despite the simulations using a total of <jats:inline-formula> <jats:alternatives> <jats:tex-math>$N=2^{36}$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000503_inline7.png\"/> </jats:alternatives> </jats:inline-formula> grid points, which would require <jats:inline-formula> <jats:alternatives> <jats:tex-math>$D=2^{18}$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000503_inline8.png\"/> </jats:alternatives> </jats:inline-formula> for full-rank calculations. Additionally, we observe that a QTN time evolution scheme based on the Dirac–Frenkel variational principle allows one to use some","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"96 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142266457","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}
Pub Date : 2024-09-18DOI: 10.1017/s0022377824000771
T. Adkins, R. Meyrand, J. Squire
Understanding the partitioning of turbulent energy between ions and electrons in weakly collisional plasmas is crucial for the accurate interpretation of observations and modelling of various astrophysical phenomena. Many such plasmas are ‘imbalanced’, wherein the large-scale energy input is dominated by Alfvénic fluctuations propagating in a single direction. In this paper, we demonstrate that when strongly-magnetised plasma turbulence is imbalanced, nonlinear conservation laws imply the existence of a critical value of the electron plasma beta (the ratio of the thermal to magnetic pressures) that separates two dramatically different types of turbulence in parameter space. For betas below the critical value, the free energy injected on the largest scales is able to undergo a familiar Kolmogorov-type cascade to small scales where it is dissipated, heating electrons. For betas above the critical value, the system forms a ‘helicity barrier’ that prevents the cascade from proceeding past the ion Larmor radius, causing the majority of the injected free energy to be deposited into ion heating. Physically, the helicity barrier results from the inability of the system to adjust to the disparity between the perpendicular-wavenumber scalings of the free energy and generalised helicity below the ion Larmor radius; restoring finite electron inertia can annul, or even reverse, this disparity, giving rise to the aforementioned critical beta. We relate this physics to the ‘dynamic phase alignment’ mechanism (that operates under yet lower beta conditions and in pair plasmas), and characterise various other important features of the helicity barrier, including the nature of the nonlinear wavenumber-space fluxes, dissipation rates, and energy spectra. The existence of such a critical beta has important implications for heating, as it suggests that the dominant recipient of the turbulent energy, ions or electrons, can depend sensitively on the characteristics of the plasma at large scales.
{"title":"The effects of finite electron inertia on helicity-barrier-mediated turbulence","authors":"T. Adkins, R. Meyrand, J. Squire","doi":"10.1017/s0022377824000771","DOIUrl":"https://doi.org/10.1017/s0022377824000771","url":null,"abstract":"Understanding the partitioning of turbulent energy between ions and electrons in weakly collisional plasmas is crucial for the accurate interpretation of observations and modelling of various astrophysical phenomena. Many such plasmas are ‘imbalanced’, wherein the large-scale energy input is dominated by Alfvénic fluctuations propagating in a single direction. In this paper, we demonstrate that when strongly-magnetised plasma turbulence is imbalanced, nonlinear conservation laws imply the existence of a critical value of the electron plasma beta (the ratio of the thermal to magnetic pressures) that separates two dramatically different types of turbulence in parameter space. For betas below the critical value, the free energy injected on the largest scales is able to undergo a familiar Kolmogorov-type cascade to small scales where it is dissipated, heating electrons. For betas above the critical value, the system forms a ‘helicity barrier’ that prevents the cascade from proceeding past the ion Larmor radius, causing the majority of the injected free energy to be deposited into ion heating. Physically, the helicity barrier results from the inability of the system to adjust to the disparity between the perpendicular-wavenumber scalings of the free energy and generalised helicity below the ion Larmor radius; restoring finite electron inertia can annul, or even reverse, this disparity, giving rise to the aforementioned critical beta. We relate this physics to the ‘dynamic phase alignment’ mechanism (that operates under yet lower beta conditions and in pair plasmas), and characterise various other important features of the helicity barrier, including the nature of the nonlinear wavenumber-space fluxes, dissipation rates, and energy spectra. The existence of such a critical beta has important implications for heating, as it suggests that the dominant recipient of the turbulent energy, ions or electrons, can depend sensitively on the characteristics of the plasma at large scales.","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"21 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269589","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}
Pub Date : 2024-09-18DOI: 10.1017/s002237782400059x
Michael Q. May, Hong Qin
The quantum three-wave interaction, the lowest-order nonlinear interaction in plasma physics, describes energy–momentum transfer between three resonant waves in the quantum regime. We describe how it may also act as a finite-degree-of-freedom approximation to the classical three-wave interaction in certain circumstances. By promoting the field variables to operators, we quantize the classical system, show that the quantum system has more free parameters than the classical system and explain how these parameters may be selected to optimize either initial or long-term correspondence. We then numerically compare the long-time quantum–classical correspondence far from the fixed point dynamics. We discuss the Poincaré recurrence of the system and the mitigation of quantum scrambling.
{"title":"Nonlinear solution of classical three-wave interaction via finite-dimensional quantum model","authors":"Michael Q. May, Hong Qin","doi":"10.1017/s002237782400059x","DOIUrl":"https://doi.org/10.1017/s002237782400059x","url":null,"abstract":"The quantum three-wave interaction, the lowest-order nonlinear interaction in plasma physics, describes energy–momentum transfer between three resonant waves in the quantum regime. We describe how it may also act as a finite-degree-of-freedom approximation to the classical three-wave interaction in certain circumstances. By promoting the field variables to operators, we quantize the classical system, show that the quantum system has more free parameters than the classical system and explain how these parameters may be selected to optimize either initial or long-term correspondence. We then numerically compare the long-time quantum–classical correspondence far from the fixed point dynamics. We discuss the Poincaré recurrence of the system and the mitigation of quantum scrambling.","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"64 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142266458","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}
Pub Date : 2024-09-18DOI: 10.1017/s0022377824001132
Anton V. Sudnikov, Ivan A. Ivanov, Anna A. Inzhevatkina, Aleksey V. Kozhevnikov, Vladimir V. Postupaev, Mikhail S. Tolkachev, Viktor O. Ustyuzhanin
The paper presents experimental results from the SMOLA device, which was built in the Budker Institute of Nuclear Physics for the verification of the helical mirror confinement idea. This concept involves active control of axial losses from the confinement zone in an open magnetic trap through the use of multiple mirrors that move in the plasma frame of reference. The discussed experiments focused on determining the cumulative effect of a helical mirror system in combination with a short segment of a stronger magnetic field. Combination of these two methods of axial flow suppression results in higher efficiency compared with each method individually. Different combinations of the mirrors were tested. The most effective flow suppression was observed if the short mirror was placed between the confinement region and the helical mirror. In this configuration, an effective mirror ratio of $R_{{rm eff}} = 32.6pm 7.8$ was achieved, along with a more than three-fold increase in plasma density within the confinement region. The possibility of a cumulative effect of different types of magnetic mirrors offers a way to improve the confinement performance of the reactor-grade mirror confinement devices.
论文介绍了巴德克核物理研究所（Budker Institute of Nuclear Physics）为验证螺旋镜约束理念而建造的 SMOLA 设备的实验结果。这一概念涉及通过使用在等离子体参照系中移动的多面镜子，主动控制开放式磁阱中禁锢区的轴向损耗。所讨论的实验侧重于确定螺旋镜系统与较强磁场短段相结合的累积效应。与单独使用每种方法相比，结合使用这两种方法抑制轴向流的效率更高。我们对不同的镜面组合进行了测试。如果将短反射镜置于约束区和螺旋反射镜之间，则可观察到最有效的流动抑制效果。在这种配置下，实现了 $R_{{rm eff}} = 32.6pm 7.8$ 的有效镜面比，同时约束区内的等离子体密度增加了三倍多。不同类型磁性反射镜的累积效应为提高反应堆级反射镜约束装置的约束性能提供了可能。
{"title":"Improved axial confinement in the open trap by the combination of helical and short mirrors","authors":"Anton V. Sudnikov, Ivan A. Ivanov, Anna A. Inzhevatkina, Aleksey V. Kozhevnikov, Vladimir V. Postupaev, Mikhail S. Tolkachev, Viktor O. Ustyuzhanin","doi":"10.1017/s0022377824001132","DOIUrl":"https://doi.org/10.1017/s0022377824001132","url":null,"abstract":"The paper presents experimental results from the SMOLA device, which was built in the Budker Institute of Nuclear Physics for the verification of the helical mirror confinement idea. This concept involves active control of axial losses from the confinement zone in an open magnetic trap through the use of multiple mirrors that move in the plasma frame of reference. The discussed experiments focused on determining the cumulative effect of a helical mirror system in combination with a short segment of a stronger magnetic field. Combination of these two methods of axial flow suppression results in higher efficiency compared with each method individually. Different combinations of the mirrors were tested. The most effective flow suppression was observed if the short mirror was placed between the confinement region and the helical mirror. In this configuration, an effective mirror ratio of <jats:inline-formula> <jats:alternatives> <jats:tex-math>$R_{{rm eff}} = 32.6pm 7.8$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824001132_inline1.png\"/> </jats:alternatives> </jats:inline-formula> was achieved, along with a more than three-fold increase in plasma density within the confinement region. The possibility of a cumulative effect of different types of magnetic mirrors offers a way to improve the confinement performance of the reactor-grade mirror confinement devices.","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"147 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142266459","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}
Pub Date : 2024-09-18DOI: 10.1017/s0022377824000734
Chaojie Zhang, Doug Storey, Pablo San Miguel Claveria, Zan Nie, Ken A. Marsh, Warren B. Mori, Erik Adli, Weiming An, Robert Ariniello, Gevy J. Cao, Christine Clark, Sebastien Corde, Thamine Dalichaouch, Christopher E. Doss, Claudio Emma, Henrik Ekerfelt, Elias Gerstmayr, Spencer Gessner, Claire Hansel, Alexander Knetsch, Valentina Lee, Fei Li, Mike Litos, Brendan O'Shea, Glen White, Gerry Yocky, Viktoriia Zakharova, Mark Hogan, Chan Joshi
This study documents several correlations observed during the first run of the plasma wakefield acceleration experiment E300 conducted at FACET-II, using a single drive electron bunch. The established correlations include those between the measured maximum energy loss of the drive electron beam and the integrated betatron X-ray signal, the calculated total beam energy deposited in the plasma and the integrated X-ray signal, among three visible light emission measuring cameras and between the visible plasma light and X-ray signal. The integrated X-ray signal correlates almost linearly with both the maximum energy loss of the drive beam and the energy deposited into the plasma, demonstrating its usability as a measure of energy transfer from the drive beam to the plasma. Visible plasma light is found to be a useful indicator of the presence of a wake at three locations that overall are two metres apart. Despite the complex dynamics and vastly different time scales, the X-ray radiation from the drive bunch and visible light emission from the plasma may prove to be effective non-invasive diagnostics for monitoring the energy transfer from the beam to the plasma in future high-repetition-rate experiments.
本研究记录了在 FACET-II 进行的等离子体汪场加速实验 E300 第一次运行期间，使用单个驱动电子束观察到的几种相关性。已建立的相关性包括：测量到的驱动电子束最大能量损失与综合贝塔电子管 X 射线信号之间的相关性、计算出的沉积在等离子体中的电子束总能量与综合 X 射线信号之间的相关性、三台可见光发射测量相机之间的相关性以及可见等离子体光与 X 射线信号之间的相关性。综合 X 射线信号与驱动光束的最大能量损失和沉积到等离子体中的能量几乎呈线性相关，这表明它可以用来测量从驱动光束到等离子体的能量转移。在相距两米的三个地点，可见等离子体光是唤醒存在的有效指标。尽管动力学过程复杂，时间尺度也大不相同，但在未来的高重复率实验中，驱动束的 X 射线辐射和等离子体的可见光发射可能会被证明是监测从束流到等离子体的能量转移的有效非侵入式诊断方法。
{"title":"Correlations between X-rays, visible light and drive-beam energy loss observed in plasma wakefield acceleration experiments at FACET-II","authors":"Chaojie Zhang, Doug Storey, Pablo San Miguel Claveria, Zan Nie, Ken A. Marsh, Warren B. Mori, Erik Adli, Weiming An, Robert Ariniello, Gevy J. Cao, Christine Clark, Sebastien Corde, Thamine Dalichaouch, Christopher E. Doss, Claudio Emma, Henrik Ekerfelt, Elias Gerstmayr, Spencer Gessner, Claire Hansel, Alexander Knetsch, Valentina Lee, Fei Li, Mike Litos, Brendan O'Shea, Glen White, Gerry Yocky, Viktoriia Zakharova, Mark Hogan, Chan Joshi","doi":"10.1017/s0022377824000734","DOIUrl":"https://doi.org/10.1017/s0022377824000734","url":null,"abstract":"This study documents several correlations observed during the first run of the plasma wakefield acceleration experiment E300 conducted at FACET-II, using a single drive electron bunch. The established correlations include those between the measured maximum energy loss of the drive electron beam and the integrated betatron X-ray signal, the calculated total beam energy deposited in the plasma and the integrated X-ray signal, among three visible light emission measuring cameras and between the visible plasma light and X-ray signal. The integrated X-ray signal correlates almost linearly with both the maximum energy loss of the drive beam and the energy deposited into the plasma, demonstrating its usability as a measure of energy transfer from the drive beam to the plasma. Visible plasma light is found to be a useful indicator of the presence of a wake at three locations that overall are two metres apart. Despite the complex dynamics and vastly different time scales, the X-ray radiation from the drive bunch and visible light emission from the plasma may prove to be effective non-invasive diagnostics for monitoring the energy transfer from the beam to the plasma in future high-repetition-rate experiments.","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"8 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269588","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}
Pub Date : 2024-09-18DOI: 10.1017/s0022377824000746
P. Helander, R.J.J. Mackenbach
The available energy of a plasma is defined as the maximum amount by which the plasma energy can be lowered by volume-preserving rearrangements in phase space, so-called Gardner restacking. A general expression is derived for the available energy of a nearly homogeneous plasma and is shown to be closely related to the Helmholtz free energy, which it can never exceed. A number of explicit examples are given.
{"title":"Available energy of plasmas with small fluctuations","authors":"P. Helander, R.J.J. Mackenbach","doi":"10.1017/s0022377824000746","DOIUrl":"https://doi.org/10.1017/s0022377824000746","url":null,"abstract":"The available energy of a plasma is defined as the maximum amount by which the plasma energy can be lowered by volume-preserving rearrangements in phase space, so-called Gardner restacking. A general expression is derived for the available energy of a nearly homogeneous plasma and is shown to be closely related to the Helmholtz free energy, which it can never exceed. A number of explicit examples are given.","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"28 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142266722","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}
Pub Date : 2024-06-03DOI: 10.1017/s0022377824000618
D.P. Higginson, R. Lelièvre, L. Vassura, M.M. Gugiu, M. Borghesi, L.A. Bernstein, D. L. Bleuel, B. L. Goldblum, A. Green, F. Hannachi, S. Kar, S. Kisyov, L. Quentin, M. Schroer, M. Tarisien, O. Willi, P. Antici, F. Negoita, A. Allaoua, J. Fuchs
Laser-driven neutron sources are routinely produced by the interaction of laser-accelerated protons with a converter. They present complementary characteristics to those of conventional accelerator-based neutron sources (e.g. short pulse durations, enabling novel applications like radiography). We present here results from an experiment aimed at performing a global characterization of the neutrons produced using the Titan laser at the Jupiter Laser Facility (Livermore, USA), where protons were accelerated from 23 $mathrm {mu }$m thick plastic targets and directed onto a LiF converter to produce neutrons. For this purpose, several diagnostics were used to measure these neutron emissions, such as CR-39, activation foils, time-of-flight detectors and direct measurement of $^7{rm Be}$ residual activity in the LiF converters. The use of these different, independently operating diagnostics enables comparison of the various measurements performed to provide a robust characterization. These measurements led to a neutron yield of $2.0times 10^{9}$ neutrons per shot with a modest angular dependence, close to that simulated.
{"title":"Global characterization of a laser-generated neutron source","authors":"D.P. Higginson, R. Lelièvre, L. Vassura, M.M. Gugiu, M. Borghesi, L.A. Bernstein, D. L. Bleuel, B. L. Goldblum, A. Green, F. Hannachi, S. Kar, S. Kisyov, L. Quentin, M. Schroer, M. Tarisien, O. Willi, P. Antici, F. Negoita, A. Allaoua, J. Fuchs","doi":"10.1017/s0022377824000618","DOIUrl":"https://doi.org/10.1017/s0022377824000618","url":null,"abstract":"<p>Laser-driven neutron sources are routinely produced by the interaction of laser-accelerated protons with a converter. They present complementary characteristics to those of conventional accelerator-based neutron sources (e.g. short pulse durations, enabling novel applications like radiography). We present here results from an experiment aimed at performing a global characterization of the neutrons produced using the Titan laser at the Jupiter Laser Facility (Livermore, USA), where protons were accelerated from 23 <span><span><span data-mathjax-type=\"texmath\"><span>$mathrm {mu }$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240601163003128-0856:S0022377824000618:S0022377824000618_inline1.png\"/></span></span>m thick plastic targets and directed onto a LiF converter to produce neutrons. For this purpose, several diagnostics were used to measure these neutron emissions, such as CR-39, activation foils, time-of-flight detectors and direct measurement of <span><span><span data-mathjax-type=\"texmath\"><span>$^7{rm Be}$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240601163003128-0856:S0022377824000618:S0022377824000618_inline2.png\"/></span></span> residual activity in the LiF converters. The use of these different, independently operating diagnostics enables comparison of the various measurements performed to provide a robust characterization. These measurements led to a neutron yield of <span><span><span data-mathjax-type=\"texmath\"><span>$2.0times 10^{9}$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240601163003128-0856:S0022377824000618:S0022377824000618_inline3.png\"/></span></span> neutrons per shot with a modest angular dependence, close to that simulated.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"17 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141252735","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}
Pub Date : 2024-05-22DOI: 10.1017/s0022377824000540
A. Wiedman, S. Buller, M. Landreman
Filament-based coil optimizations are performed for several quasi-helical stellarator configurations, beginning with the one from Landreman & Paul (<jats:italic>Phys. Rev. Lett.</jats:italic>, vol. 128, 2022, 035001), demonstrating that precise quasi-helical symmetry can be achieved with realistic coils. Several constraints are placed on the shape and spacing of the coils, such as low curvature and sufficient plasma–coil distance for neutron shielding. The coils resulting from this optimization have a maximum curvature 0.8 times that of the coils of the Helically Symmetric eXperiment (HSX) and a mean squared curvature 0.4 times that of the HSX coils when scaled to the same plasma minor radius. When scaled up to reactor size and magnetic field strength, no fast particle losses were found in the free-boundary configuration when simulating 5000 alpha particles launched at <jats:inline-formula> <jats:alternatives> <jats:tex-math>$3.5,mathrm {MeV}$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000540_inline1.png"/> </jats:alternatives> </jats:inline-formula> on the flux surface with a normalized toroidal flux of <jats:inline-formula> <jats:alternatives> <jats:tex-math>$s=0.5$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000540_inline2.png"/> </jats:alternatives> </jats:inline-formula>. An analysis of the tolerance of the coils to manufacturing errors is performed using a Gaussian process model, and the coils are found to maintain low particle losses for smooth, large-scale errors up to amplitudes of approximately <jats:inline-formula> <jats:alternatives> <jats:tex-math>$0.15,mathrm {m}$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000540_inline3.png"/> </jats:alternatives> </jats:inline-formula>. Another coil optimization is performed for the Landreman–Paul configuration with the additional constraint that the coils are purely planar. Visual inspection of the Poincaré plot of the resulting magnetic field-lines reveal that the planar modular coils alone do a poor job of reproducing the target equilibrium. Additional non-planar coil optimizations are performed for the quasi-helical configuration with <jats:inline-formula> <jats:alternatives> <jats:tex-math>$5,%$</jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0022377824000540_inline4.png"/> </jats:alternatives> </jats:inline-formula> volume-averaged plasma beta from Landreman <jats:italic>et al.</jats:italic> (<jats:italic>Phys. Plasma</jats:italic>, vol. 29, issue 8, 2022, 082501), and a similar configuration also optimized to satisfy the Mercier criterion. The finite beta configurations had larger fast-particle losses, with the free-boundary Mercier-optimized configuration performing the worst, losing approxi
{"title":"Coil optimization for quasi-helically symmetric stellarator configurations","authors":"A. Wiedman, S. Buller, M. Landreman","doi":"10.1017/s0022377824000540","DOIUrl":"https://doi.org/10.1017/s0022377824000540","url":null,"abstract":"Filament-based coil optimizations are performed for several quasi-helical stellarator configurations, beginning with the one from Landreman & Paul (<jats:italic>Phys. Rev. Lett.</jats:italic>, vol. 128, 2022, 035001), demonstrating that precise quasi-helical symmetry can be achieved with realistic coils. Several constraints are placed on the shape and spacing of the coils, such as low curvature and sufficient plasma–coil distance for neutron shielding. The coils resulting from this optimization have a maximum curvature 0.8 times that of the coils of the Helically Symmetric eXperiment (HSX) and a mean squared curvature 0.4 times that of the HSX coils when scaled to the same plasma minor radius. When scaled up to reactor size and magnetic field strength, no fast particle losses were found in the free-boundary configuration when simulating 5000 alpha particles launched at <jats:inline-formula> <jats:alternatives> <jats:tex-math>$3.5,mathrm {MeV}$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000540_inline1.png\"/> </jats:alternatives> </jats:inline-formula> on the flux surface with a normalized toroidal flux of <jats:inline-formula> <jats:alternatives> <jats:tex-math>$s=0.5$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000540_inline2.png\"/> </jats:alternatives> </jats:inline-formula>. An analysis of the tolerance of the coils to manufacturing errors is performed using a Gaussian process model, and the coils are found to maintain low particle losses for smooth, large-scale errors up to amplitudes of approximately <jats:inline-formula> <jats:alternatives> <jats:tex-math>$0.15,mathrm {m}$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000540_inline3.png\"/> </jats:alternatives> </jats:inline-formula>. Another coil optimization is performed for the Landreman–Paul configuration with the additional constraint that the coils are purely planar. Visual inspection of the Poincaré plot of the resulting magnetic field-lines reveal that the planar modular coils alone do a poor job of reproducing the target equilibrium. Additional non-planar coil optimizations are performed for the quasi-helical configuration with <jats:inline-formula> <jats:alternatives> <jats:tex-math>$5,%$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0022377824000540_inline4.png\"/> </jats:alternatives> </jats:inline-formula> volume-averaged plasma beta from Landreman <jats:italic>et al.</jats:italic> (<jats:italic>Phys. Plasma</jats:italic>, vol. 29, issue 8, 2022, 082501), and a similar configuration also optimized to satisfy the Mercier criterion. The finite beta configurations had larger fast-particle losses, with the free-boundary Mercier-optimized configuration performing the worst, losing approxi","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"45 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141150955","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}
m thick plastic targets and directed onto a LiF converter to produce neutrons. For this purpose, several diagnostics were used to measure these neutron emissions, such as CR-39, activation foils, time-of-flight detectors and direct measurement of $^7{rm Be}$
residual activity in the LiF converters. The use of these different, independently operating diagnostics enables comparison of the various measurements performed to provide a robust characterization. These measurements led to a neutron yield of $2.0times 10^{9}$
neutrons per shot with a modest angular dependence, close to that simulated.
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