Tian Dong, Yong Zhi Zhang, Aihua Liu, Yew Kam Ho, Li Guang Jiao
The singlet S-wave resonances of the He atom embedded in dense quantum plasmas are investigated by applying the complex-coordinate rotation method. The modified Debye–Hückel potential is used to model the effective interactions of the test atom in a dense quantum plasma environment. The explicitly correlated Hylleraas configuration-interaction basis function is employed to take into account the electron correlation effect. The first ten S-wave resonance states of the He atom below the N = 2 thresholds of the He+ ion are calculated, and the resonance energies and widths at a variety of screening parameters are obtained with high accuracy. The plasma screening effect on the expectation values of the radial and angular physical quantities are analyzed for the first time.
应用复坐标旋转方法研究了嵌入致密量子等离子体中的氦原子的单S波共振。修正的 Debye-Hückel 势用于模拟高密度量子等离子体环境中测试原子的有效相互作用。为了考虑电子相关效应，采用了显式相关的 Hylleraas 配置-相互作用基函数。计算了 He+ 离子 N = 2 阈值以下 He 原子的前十个 S 波共振态，并高精度地获得了各种屏蔽参数下的共振能量和宽度。首次分析了等离子体屏蔽对径向和角度物理量期望值的影响。
{"title":"The singlet S-wave resonances of He atom in dense quantum plasmas","authors":"Tian Dong, Yong Zhi Zhang, Aihua Liu, Yew Kam Ho, Li Guang Jiao","doi":"10.1063/5.0217126","DOIUrl":"https://doi.org/10.1063/5.0217126","url":null,"abstract":"The singlet S-wave resonances of the He atom embedded in dense quantum plasmas are investigated by applying the complex-coordinate rotation method. The modified Debye–Hückel potential is used to model the effective interactions of the test atom in a dense quantum plasma environment. The explicitly correlated Hylleraas configuration-interaction basis function is employed to take into account the electron correlation effect. The first ten S-wave resonance states of the He atom below the N = 2 thresholds of the He+ ion are calculated, and the resonance energies and widths at a variety of screening parameters are obtained with high accuracy. The plasma screening effect on the expectation values of the radial and angular physical quantities are analyzed for the first time.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"29 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221865","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}
P. Tchórz, T. Chodukowski, M. Rosiński, S. Borodziuk, M. Szymański, R. Dudžák, S. Singh, M. Krupka, T. Burian, A. Marchenko, M. Kustosz, S. Agarwal
In this Letter, we report the possibility of generating intense, highly energetic proton beams using terawatt, sub-nanosecond class laser system by irradiating modified cavity pressure acceleration-type targets. In this approach, the main source of few-mega electron volt protons is thermonuclear deuterium–deuterium reaction; therefore, the energy spectrum of accelerated particles and their number is not as strongly related to the laser intensity (laser pulse energy and pulse duration in particular) as in the case of the most common ion acceleration mechanism, namely, target normal sheath acceleration. Performed Monte Carlo simulations suggest that using mentioned mechanism to generate proton beam might be beneficial and efficient driver for laser induced proton–boron fusion when moderate-to-low laser pulse intensities ( ⩽ 1016W/cm2) and thin, lower than 100 μm boron foils are used as catchers.
{"title":"Proton beams generated via thermonuclear deuterium–deuterium fusion by means of modified cavity pressure acceleration-type targets as a candidate for proton–boron fusion driver","authors":"P. Tchórz, T. Chodukowski, M. Rosiński, S. Borodziuk, M. Szymański, R. Dudžák, S. Singh, M. Krupka, T. Burian, A. Marchenko, M. Kustosz, S. Agarwal","doi":"10.1063/5.0207108","DOIUrl":"https://doi.org/10.1063/5.0207108","url":null,"abstract":"In this Letter, we report the possibility of generating intense, highly energetic proton beams using terawatt, sub-nanosecond class laser system by irradiating modified cavity pressure acceleration-type targets. In this approach, the main source of few-mega electron volt protons is thermonuclear deuterium–deuterium reaction; therefore, the energy spectrum of accelerated particles and their number is not as strongly related to the laser intensity (laser pulse energy and pulse duration in particular) as in the case of the most common ion acceleration mechanism, namely, target normal sheath acceleration. Performed Monte Carlo simulations suggest that using mentioned mechanism to generate proton beam might be beneficial and efficient driver for laser induced proton–boron fusion when moderate-to-low laser pulse intensities ( ⩽ 1016W/cm2) and thin, lower than 100 μm boron foils are used as catchers.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"40 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221864","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}
Muhammad Khawar Nadeem, Shaomeng Wang, Atif Jameel, Bilawal Ali, Jibran Latif, Yubin Gong
Gridless inductive output tubes (IOTs) offer compact size and high-power amplification at sub-GHz frequencies. Minimizing cavity dimensions in the interest of compactness leads to smaller gaps, which may cause multipactor discharge under high-power operating conditions. The uncontrolled electron growth resulting from multipactor breakdown can lead to undesired effects including surface damage and system failure. This paper performs a parallel-plate multipactor analysis for a high-Q, L-shaped, aluminum, 431 MHz cavity designed for a gridless IOT to be operated in the MW-power regime. The cavity gap is 27 mm, and diameter is 339 mm. Multipactor susceptibility regions are calculated for non-zero emission energy, half-cycle, and non-half-cycle multipactor using a semi-analytic approach and a standard aluminum secondary electron yield (SEY) curve. The analytical results are validated with particle-in-cell simulation in CST Studio. Simulation results show a voltage range of 6.4–19 kV, compared to the analytically calculated values of 8.2 and 18.3 kV for the lower and upper bounds, respectively. Fluorocarbon coating as a means to reduce secondary electron emission is simulated, which shows 46% reduction in peak particle population with an 11.2 nm PTFE coating, with further reduction as coating thickness increases. The results show that the L-shaped cavity is a suitable choice for this IOT design as it does not exhibit single-surface multipactor and will not develop two-surface multipactor at full-power operation.
{"title":"Multipactor analysis of 431 MHz L-shaped inductive output tube cavity","authors":"Muhammad Khawar Nadeem, Shaomeng Wang, Atif Jameel, Bilawal Ali, Jibran Latif, Yubin Gong","doi":"10.1063/5.0217471","DOIUrl":"https://doi.org/10.1063/5.0217471","url":null,"abstract":"Gridless inductive output tubes (IOTs) offer compact size and high-power amplification at sub-GHz frequencies. Minimizing cavity dimensions in the interest of compactness leads to smaller gaps, which may cause multipactor discharge under high-power operating conditions. The uncontrolled electron growth resulting from multipactor breakdown can lead to undesired effects including surface damage and system failure. This paper performs a parallel-plate multipactor analysis for a high-Q, L-shaped, aluminum, 431 MHz cavity designed for a gridless IOT to be operated in the MW-power regime. The cavity gap is 27 mm, and diameter is 339 mm. Multipactor susceptibility regions are calculated for non-zero emission energy, half-cycle, and non-half-cycle multipactor using a semi-analytic approach and a standard aluminum secondary electron yield (SEY) curve. The analytical results are validated with particle-in-cell simulation in CST Studio. Simulation results show a voltage range of 6.4–19 kV, compared to the analytically calculated values of 8.2 and 18.3 kV for the lower and upper bounds, respectively. Fluorocarbon coating as a means to reduce secondary electron emission is simulated, which shows 46% reduction in peak particle population with an 11.2 nm PTFE coating, with further reduction as coating thickness increases. The results show that the L-shaped cavity is a suitable choice for this IOT design as it does not exhibit single-surface multipactor and will not develop two-surface multipactor at full-power operation.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"60 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221866","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}
C. Courtois, R. Gisbert, R. Botrel, A. Chaleil, L. Chopineau, S. Debesset, J. Fariaut, O. Henry, L. Le Déroff, B. Loupias, A. Rousseau, G. Soullie, B. Villette
We detail results of two experiments performed at the Laser Mégajoule (LMJ) facility aimed at studying similar supersonic Marshak waves propagating in a low-density SiO2 aerogel enclosed in metallic tubes. Similar means here that these two experiments, driven by the same input radiation temperature history, use purposely very different tubes in terms of length (L = 1200 or 2000 μm), diameter (2R = 1000 or 2000 μm), nature of the wall (gold or copper), and aerogel densities (ρ = 30 or 20 mg/cm3), yet the transit time and the radiation temperature of the fronts at the tube exit are the same for both shots. Marshak waves are characterized at the exit using simultaneously for the first time to our knowledge, a one dimensional soft x-ray imager from which the radiation front transit time and curvature are measured and also a broadband x-ray spectrometer to infer its temperature history. These constraining results are then successfully compared to those from simple analytical models [Cohen et al., Phys. Rev. Res. 2, 023007 (2020) and Hurricane et al., Phys. Plasmas 13, 113303 (2006)] and from the three dimensional Lagrangian radiation-hydrodynamics code TROLL to get information on x-ray energy losses. Controlled compensation effects between the length, diameter, and nature of the tubes (governing these losses) are such that the radiation temperature drop along the tubes is eventually the same for these two similar shots.
{"title":"Characterization of similar Marshak waves observed at the LMJ","authors":"C. Courtois, R. Gisbert, R. Botrel, A. Chaleil, L. Chopineau, S. Debesset, J. Fariaut, O. Henry, L. Le Déroff, B. Loupias, A. Rousseau, G. Soullie, B. Villette","doi":"10.1063/5.0216671","DOIUrl":"https://doi.org/10.1063/5.0216671","url":null,"abstract":"We detail results of two experiments performed at the Laser Mégajoule (LMJ) facility aimed at studying similar supersonic Marshak waves propagating in a low-density SiO2 aerogel enclosed in metallic tubes. Similar means here that these two experiments, driven by the same input radiation temperature history, use purposely very different tubes in terms of length (L = 1200 or 2000 μm), diameter (2R = 1000 or 2000 μm), nature of the wall (gold or copper), and aerogel densities (ρ = 30 or 20 mg/cm3), yet the transit time and the radiation temperature of the fronts at the tube exit are the same for both shots. Marshak waves are characterized at the exit using simultaneously for the first time to our knowledge, a one dimensional soft x-ray imager from which the radiation front transit time and curvature are measured and also a broadband x-ray spectrometer to infer its temperature history. These constraining results are then successfully compared to those from simple analytical models [Cohen et al., Phys. Rev. Res. 2, 023007 (2020) and Hurricane et al., Phys. Plasmas 13, 113303 (2006)] and from the three dimensional Lagrangian radiation-hydrodynamics code TROLL to get information on x-ray energy losses. Controlled compensation effects between the length, diameter, and nature of the tubes (governing these losses) are such that the radiation temperature drop along the tubes is eventually the same for these two similar shots.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"7 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221867","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}
William E. Lewis, David A. Yager-Elorriaga, Christopher A. Jennings, Jeffrey R. Fein, Gabriel A. Shipley, Andrew Porwitzky, Thomas J. Awe, Matthew R. Gomez, Eric C. Harding, Adam J. Harvey-Thompson, Patrick F. Knapp, Owen M. Mannion, Daniel E. Ruiz, Marc-Andre Schaeuble, Stephen A. Slutz, Matthew R. Weis, Jeffrey Woolstrum, David J. Ampleford, Luke Shulenburger
In magnetized liner inertial fusion (MagLIF), a cylindrical liner filled with fusion fuel is imploded with the goal of producing a one-dimensional plasma column at thermonuclear conditions. However, structures attributed to three-dimensional effects are observed in self-emission x-ray images. Despite this, the impact of many experimental inputs on the column morphology has not been characterized. We demonstrate the use of a linear regression analysis to explore correlations between morphology and a wide variety of experimental inputs across 57 MagLIF experiments. Results indicate the possibility of several unexplored effects. For example, we demonstrate that increasing the initial magnetic field correlates with improved stability. Although intuitively expected, this has never been quantitatively assessed in integrated MagLIF experiments. We also demonstrate that azimuthal drive asymmetries resulting from the geometry of the “current return can” appear to measurably impact the morphology. In conjunction with several counterintuitive null results, we expect the observed correlations will encourage further experimental, theoretical, and simulation-based studies. Finally, we note that the method used in this work is general and may be applied to explore not only correlations between input conditions and morphology but also with other experimentally measured quantities.
在磁化衬垫惯性聚变（MagLIF）中，充满聚变燃料的圆柱形衬垫被内爆，目的是在热核条件下产生一维等离子体柱。然而，在自发射 X 射线图像中可以观察到归因于三维效应的结构。尽管如此，许多实验输入对等离子体柱形态的影响还没有得到表征。我们展示了如何使用线性回归分析来探索 57 次 MagLIF 实验中形态与各种实验输入之间的相关性。结果表明可能存在几种尚未探索的效应。例如，我们证明增加初始磁场与提高稳定性相关。虽然这是直观预期的结果，但在综合 MagLIF 实验中从未进行过定量评估。我们还证明，"电流回流 "的几何形状导致的方位驱动不对称似乎对形态产生了可测量的影响。结合几个反直觉的无效结果，我们希望观察到的相关性将鼓励进一步的实验、理论和模拟研究。最后，我们指出，这项工作中使用的方法是通用的，不仅可用于探索输入条件与形态之间的相关性，还可用于探索与其他实验测量量之间的相关性。
{"title":"Mining experimental magnetized liner inertial fusion data: Trends in stagnation morphology","authors":"William E. Lewis, David A. Yager-Elorriaga, Christopher A. Jennings, Jeffrey R. Fein, Gabriel A. Shipley, Andrew Porwitzky, Thomas J. Awe, Matthew R. Gomez, Eric C. Harding, Adam J. Harvey-Thompson, Patrick F. Knapp, Owen M. Mannion, Daniel E. Ruiz, Marc-Andre Schaeuble, Stephen A. Slutz, Matthew R. Weis, Jeffrey Woolstrum, David J. Ampleford, Luke Shulenburger","doi":"10.1063/5.0206222","DOIUrl":"https://doi.org/10.1063/5.0206222","url":null,"abstract":"In magnetized liner inertial fusion (MagLIF), a cylindrical liner filled with fusion fuel is imploded with the goal of producing a one-dimensional plasma column at thermonuclear conditions. However, structures attributed to three-dimensional effects are observed in self-emission x-ray images. Despite this, the impact of many experimental inputs on the column morphology has not been characterized. We demonstrate the use of a linear regression analysis to explore correlations between morphology and a wide variety of experimental inputs across 57 MagLIF experiments. Results indicate the possibility of several unexplored effects. For example, we demonstrate that increasing the initial magnetic field correlates with improved stability. Although intuitively expected, this has never been quantitatively assessed in integrated MagLIF experiments. We also demonstrate that azimuthal drive asymmetries resulting from the geometry of the “current return can” appear to measurably impact the morphology. In conjunction with several counterintuitive null results, we expect the observed correlations will encourage further experimental, theoretical, and simulation-based studies. Finally, we note that the method used in this work is general and may be applied to explore not only correlations between input conditions and morphology but also with other experimentally measured quantities.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"22 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221868","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}
Lei Zhang, Lingzhao Ji, Yuexing Zhao, Ruiming Su, Guokai Yi, Yuren Shi
The transmission characteristics of terahertz (THz) waves in a non-uniform microplasma are investigated by using the scattering matrix method. The electron density distribution in microplasma is simulated by Epstein and parabolic models. The effects of physical parameters, such as the incidence angle of THz waves, microplasma size, electron density, and collision frequency, on the propagation of THz waves are numerically analyzed. The results show that lower frequency THz waves are difficult to penetrate the microplasma with high electron density and high collision frequency. The microplasma density distribution, especially the gradient variation of the density in the first layer, has a large effect on the reflection of THz waves. Thus, THz waves can be used to diagnose the physical parameters of microplasmas.
{"title":"Propagation characteristics of obliquely incident terahertz waves in inhomogeneous microplasma","authors":"Lei Zhang, Lingzhao Ji, Yuexing Zhao, Ruiming Su, Guokai Yi, Yuren Shi","doi":"10.1063/5.0216378","DOIUrl":"https://doi.org/10.1063/5.0216378","url":null,"abstract":"The transmission characteristics of terahertz (THz) waves in a non-uniform microplasma are investigated by using the scattering matrix method. The electron density distribution in microplasma is simulated by Epstein and parabolic models. The effects of physical parameters, such as the incidence angle of THz waves, microplasma size, electron density, and collision frequency, on the propagation of THz waves are numerically analyzed. The results show that lower frequency THz waves are difficult to penetrate the microplasma with high electron density and high collision frequency. The microplasma density distribution, especially the gradient variation of the density in the first layer, has a large effect on the reflection of THz waves. Thus, THz waves can be used to diagnose the physical parameters of microplasmas.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"44 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221869","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}
In this research, the electrostatically coupled multistream quasiparticle excitations are studied in the framework of the Wigner distribution function. It is remarked that the Wigner distribution of coupled multistream collective quantum excitations satisfies a simple Liouville-like evolution equation from which a generalized distribution function for multistream quasiparticle excitations is deduced. The phase-space structure of collective quantum excitations in counter-stream electron and two-stream electron–positron gas with their evolution is calculated and electron/positron hole formation due to the onset of quantum stream instability is studied in connection with the energy band structure of the multistream quantum system, for the first time. The quantum stream instabilities in symmetric and asymmetric stream systems are studied and compared. It is found that the presence of opposite-charge streams leads to overall stability due to lowering the interaction potential effect. The generalized Wigner theory is also applied to study the electron transport in a one-dimensional periodic lattice using the concept of virtual streams. Current generalized statistical formalism may be used to model different quantum phenomena in the linear excitations limit with collective electrostatic interactions. The applications extend to the stream instability in quantum charge transport in metals, semiconductors, plasmonic devices, phase-space structure of charge carriers in periodic lattices interacting with the external potential of arbitrary shape and the dynamic evolution of dense electron–positron jets in active galactic nuclei or within the extremely dense astrophysical objects.
{"title":"Statistical description of interacting multistream quantum systems","authors":"M. Akbari-Moghanjoughi","doi":"10.1063/5.0216478","DOIUrl":"https://doi.org/10.1063/5.0216478","url":null,"abstract":"In this research, the electrostatically coupled multistream quasiparticle excitations are studied in the framework of the Wigner distribution function. It is remarked that the Wigner distribution of coupled multistream collective quantum excitations satisfies a simple Liouville-like evolution equation from which a generalized distribution function for multistream quasiparticle excitations is deduced. The phase-space structure of collective quantum excitations in counter-stream electron and two-stream electron–positron gas with their evolution is calculated and electron/positron hole formation due to the onset of quantum stream instability is studied in connection with the energy band structure of the multistream quantum system, for the first time. The quantum stream instabilities in symmetric and asymmetric stream systems are studied and compared. It is found that the presence of opposite-charge streams leads to overall stability due to lowering the interaction potential effect. The generalized Wigner theory is also applied to study the electron transport in a one-dimensional periodic lattice using the concept of virtual streams. Current generalized statistical formalism may be used to model different quantum phenomena in the linear excitations limit with collective electrostatic interactions. The applications extend to the stream instability in quantum charge transport in metals, semiconductors, plasmonic devices, phase-space structure of charge carriers in periodic lattices interacting with the external potential of arbitrary shape and the dynamic evolution of dense electron–positron jets in active galactic nuclei or within the extremely dense astrophysical objects.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"8 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221871","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}
We proposed a dynamic mitigation method for plasma instabilities based on a phase control to mitigate plasma instabilities and to smooth plasma non-uniformities [e.g., Phys. Plasmas, 19 (2012), 024503]. In plasmas, perturbation phase would be unknown in general, and instability growth rate is discussed. However, if the perturbation is introduced by, for example, an illumination non-uniformity of an input energy driver beam, the perturbation phase would be defined by the driver illumination non-uniformity itself. When the driver axis is controlled by its axis oscillation or wobbling motion, the perturbation phase would be known and controlled. By the superimposition of the growing phase-controlled perturbations, the overall plasma instability growth is mitigated. The dynamic mitigation method is effective to mitigate growths of various plasma instabilities. At the same time, it was found that the phase of the growing perturbations mitigated would be still defined by the initial imprint. In this paper, the initial imprint effect is focused on the dynamic mitigation mechanism in plasmas. The results in this paper demonstrate that the initial imprint effect is reduced by an appropriate pulse shaping of the oscillating or wobbling perturbation.
{"title":"Initial imprint effect on dynamic mitigation of plasma instability","authors":"S. Kawata","doi":"10.1063/5.0225109","DOIUrl":"https://doi.org/10.1063/5.0225109","url":null,"abstract":"We proposed a dynamic mitigation method for plasma instabilities based on a phase control to mitigate plasma instabilities and to smooth plasma non-uniformities [e.g., Phys. Plasmas, 19 (2012), 024503]. In plasmas, perturbation phase would be unknown in general, and instability growth rate is discussed. However, if the perturbation is introduced by, for example, an illumination non-uniformity of an input energy driver beam, the perturbation phase would be defined by the driver illumination non-uniformity itself. When the driver axis is controlled by its axis oscillation or wobbling motion, the perturbation phase would be known and controlled. By the superimposition of the growing phase-controlled perturbations, the overall plasma instability growth is mitigated. The dynamic mitigation method is effective to mitigate growths of various plasma instabilities. At the same time, it was found that the phase of the growing perturbations mitigated would be still defined by the initial imprint. In this paper, the initial imprint effect is focused on the dynamic mitigation mechanism in plasmas. The results in this paper demonstrate that the initial imprint effect is reduced by an appropriate pulse shaping of the oscillating or wobbling perturbation.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"284 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221897","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}
Y.-F. Shi, S. Ren, H.-K. Chung, J. S. Wark, S. M. Vinko
Knowing the characteristic relaxation time of free electrons in a dense plasma is crucial to our understanding of plasma equilibration and transport. However, experimental investigations of electron relaxation dynamics have been hindered by the ultrafast, sub-femtosecond timescales on which these interactions typically take place. Here, we propose a novel approach that uses x rays from a free electron laser to generate well-defined non-thermal electron distributions, which can then be tracked via emission spectroscopy from radiative recombination as they thermalize. Collisional radiative simulations reveal how this method can enable the measurement of electron relaxation timescales in situ, shedding light on the applicability and accuracy of the Coulomb logarithm framework for modeling collisions in dense plasmas.
了解高密度等离子体中自由电子的特征弛豫时间对于我们理解等离子体的平衡和传输至关重要。然而，对电子弛豫动力学的实验研究一直受阻于这些相互作用通常发生的超快亚飞秒时间尺度。在这里，我们提出了一种新方法，利用自由电子激光器发出的 X 射线来产生定义明确的非热电子分布，然后通过辐射重组的发射光谱来跟踪它们的热化过程。碰撞辐射模拟揭示了这种方法如何能够在原位测量电子弛豫时标，并阐明了库仑对数框架在高密度等离子体碰撞建模中的适用性和准确性。
{"title":"Exploring relaxation dynamics in warm dense plasmas by tailoring non-thermal electron distributions with a free electron laser","authors":"Y.-F. Shi, S. Ren, H.-K. Chung, J. S. Wark, S. M. Vinko","doi":"10.1063/5.0217826","DOIUrl":"https://doi.org/10.1063/5.0217826","url":null,"abstract":"Knowing the characteristic relaxation time of free electrons in a dense plasma is crucial to our understanding of plasma equilibration and transport. However, experimental investigations of electron relaxation dynamics have been hindered by the ultrafast, sub-femtosecond timescales on which these interactions typically take place. Here, we propose a novel approach that uses x rays from a free electron laser to generate well-defined non-thermal electron distributions, which can then be tracked via emission spectroscopy from radiative recombination as they thermalize. Collisional radiative simulations reveal how this method can enable the measurement of electron relaxation timescales in situ, shedding light on the applicability and accuracy of the Coulomb logarithm framework for modeling collisions in dense plasmas.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"5 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221898","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}
High-beta plasma equilibria are realized in a number of physical systems, from planetary magnetospheres, sunspots, and magnetic holes to fusion laboratory experiments. When plasma pressure becomes large enough to completely expel the magnetic field from its volume, the particle trajectories cannot be considered any more as circular gyro-orbits, and plasma pressure ceases to be gyrotropic. These non-gyrotropic effects require kinetic description and are actively studied for a long time in the magnetic reconnection problem. In this paper, we will show that non-gyrotropy of plasma pressure makes it possible to markedly exceed the limit β=1 dictated by the magnetohydrodynamics for finite-size plasmas, which may be attractive for some fusion schemes such as mirror and cusp configurations. As a first step, we study how these effects manifest themselves in a simple classical problem of confining a cylindrical plasma column by a uniform vacuum magnetic field. Using particle-in-cell simulations, we show that the equilibrium of the diamagnetic bubble type with zero internal magnetic field is formed with an electron-produced current layer of sub-ion scale and found that the gas-kinetic pressure of the central plasma exceeds the pressure of the vacuum magnetic field by 15%.
{"title":"Formation of cylindrical plasma equilibria with β > 1","authors":"I. V. Timofeev, V. A. Kurshakov, E. A. Berendeev","doi":"10.1063/5.0216073","DOIUrl":"https://doi.org/10.1063/5.0216073","url":null,"abstract":"High-beta plasma equilibria are realized in a number of physical systems, from planetary magnetospheres, sunspots, and magnetic holes to fusion laboratory experiments. When plasma pressure becomes large enough to completely expel the magnetic field from its volume, the particle trajectories cannot be considered any more as circular gyro-orbits, and plasma pressure ceases to be gyrotropic. These non-gyrotropic effects require kinetic description and are actively studied for a long time in the magnetic reconnection problem. In this paper, we will show that non-gyrotropy of plasma pressure makes it possible to markedly exceed the limit β=1 dictated by the magnetohydrodynamics for finite-size plasmas, which may be attractive for some fusion schemes such as mirror and cusp configurations. As a first step, we study how these effects manifest themselves in a simple classical problem of confining a cylindrical plasma column by a uniform vacuum magnetic field. Using particle-in-cell simulations, we show that the equilibrium of the diamagnetic bubble type with zero internal magnetic field is formed with an electron-produced current layer of sub-ion scale and found that the gas-kinetic pressure of the central plasma exceeds the pressure of the vacuum magnetic field by 15%.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"9 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221896","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}
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