Physics of Plasmas最新文献_第6页

Initial imprint effect on dynamic mitigation of plasma instability 初始印记对动态缓解等离子体不稳定性的影响

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-23 DOI: 10.1063/5.0225109

S. Kawata

{"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}

引用次数: 0

Exploring relaxation dynamics in warm dense plasmas by tailoring non-thermal electron distributions with a free electron laser 用自由电子激光器定制非热电子分布，探索暖致密等离子体中的弛豫动力学

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-23 DOI: 10.1063/5.0217826

Y.-F. Shi, S. Ren, H.-K. Chung, J. S. Wark, S. M. Vinko

引用次数: 0

Formation of cylindrical plasma equilibria with β > 1 形成 β > 1 的圆柱形等离子体平衡态

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-23 DOI: 10.1063/5.0216073

I. V. Timofeev, V. A. Kurshakov, E. A. Berendeev

{"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}

引用次数: 0

Effects of wave damping and finite perpendicular scale on three-dimensional Alfvén wave parametric decay in low-beta plasmas 波阻尼和有限垂直尺度对低贝塔等离子体中三维阿尔芬波参数衰减的影响

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-23 DOI: 10.1063/5.0216871

Feiyu Li, Xiangrong Fu, Seth Dorfman

{"title":"Effects of wave damping and finite perpendicular scale on three-dimensional Alfvén wave parametric decay in low-beta plasmas","authors":"Feiyu Li, Xiangrong Fu, Seth Dorfman","doi":"10.1063/5.0216871","DOIUrl":"https://doi.org/10.1063/5.0216871","url":null,"abstract":"Shear Alfvén wave parametric decay instability (PDI) provides a potential path toward significant wave dissipation and plasma heating. However, fundamental questions regarding how PDI is excited in a realistic three-dimensional (3D) open system and how the finite perpendicular wave scale—as found in both laboratory and space plasmas—affects the excitation remain poorly understood. Here, we present the first 3D, open-boundary, hybrid kinetic-fluid simulations of kinetic Alfvén wave PDI in low-beta plasmas. Key findings are that the PDI excitation is strongly limited by the wave damping present, including electron–ion collisional damping (represented by a constant resistivity) and geometrical attenuation associated with the finite-scale Alfvén wave, and ion Landau damping of the child acoustic wave. The perpendicular wave scale alone, however, plays no discernible role: waves of different perpendicular scales exhibit similar instability excitation as long as the magnitude of the parallel ponderomotive force remains unchanged. These findings are corroborated by theoretical analysis and estimates. This new understanding of 3D kinetic Alfvén wave PDI physics is essential for laboratory study of the basic plasma process and may also aid future evaluation of the relevance/role of PDI in low-beta space plasma.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"62 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221870","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}

引用次数: 0

Kinetic model of anisotropic force-free current sheets 各向异性无力电流片的动力学模型

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-23 DOI: 10.1063/5.0213897

Ya-Ze Wu, Fan Yang, Xu-Zhi Zhou, Anton V. Artemyev, Xin An, Zhi-Yang Liu, Shan Wang, Qiu-Gang Zong

{"title":"Kinetic model of anisotropic force-free current sheets","authors":"Ya-Ze Wu, Fan Yang, Xu-Zhi Zhou, Anton V. Artemyev, Xin An, Zhi-Yang Liu, Shan Wang, Qiu-Gang Zong","doi":"10.1063/5.0213897","DOIUrl":"https://doi.org/10.1063/5.0213897","url":null,"abstract":"Force-free current sheets, characterized by field-aligned electric currents and approximately uniform plasma pressures, have been widely observed in the planetary magnetosphere and throughout the heliosphere. Recent observations of force-free current sheets have clearly shown the presence of anisotropic electron distributions with different temperatures perpendicular and parallel to the local magnetic field. In most of the kinetic models for one-dimensional, force-free current sheets, however, the electron distributions are nearly isotropic, which necessitates the construction of new models accounting for the electron temperature anisotropy. In this paper, we develop a model for anisotropic force-free current sheets, by incorporating the magnetic moment as an additional invariant of motion into the nearly isotropic electron distribution function of a previous model. Despite the different electron distributions, the electromagnetic profiles of the new model are often close to those in the nearly isotropic model. The applicability of our model is then validated via a comparison to a typical force-free current sheet in the Jovian magnetodisk, which shows good agreement between the model and the observations.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"12 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221895","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}

引用次数: 0

On the importance of separators as sites of 3D magnetic reconnection 分离器作为三维磁重联场所的重要性

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-22 DOI: 10.1063/5.0189787

C. E. Parnell

{"title":"On the importance of separators as sites of 3D magnetic reconnection","authors":"C. E. Parnell","doi":"10.1063/5.0189787","DOIUrl":"https://doi.org/10.1063/5.0189787","url":null,"abstract":"For 3D magnetic reconnection to occur there must exist a volume within which the electric field component parallel to the magnetic field is non-zero. In numerical experiments, locations of non-zero parallel electric field indicate sites of 3D magnetic reconnection. If these experiments contain all types of topological feature (null points, separatrix surfaces, spines and separators), then comparing topological features with the reconnection sites reveals that all the reconnection sites are threaded by separators with the local maxima/minima of the integrated parallel electric along fieldlines coinciding with these separators. However, not all separators thread a reconnection site. Furthermore, there are different types of separator. Cluster separators are short arising within an individual weak magnetic field region and have little parallel electric field along them so are not associated with much reconnection. Intercluster separators connect a positive null point lying in one weak-field region to a negative null point that lies in a different weak-field region. Intercluster separators often thread enhanced regions of parallel electric field and are long. Since separators form the boundary between four globally significant topologically distinct domains, they are important sites of reconnection, which can result in the global restructuring of the magnetic field. By considering kinematic bifurcation models in which separators form, it is possible to understand the formation of cluster and intercluster separators and explain their key properties.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"12 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221902","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}

引用次数: 0

Flowing plasma rearrangement in the presence of static perturbing fields 存在静态扰动场的流动等离子体重排

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-22 DOI: 10.1063/5.0222129

T. Rubin, I. E. Ochs, N. J. Fisch

{"title":"Flowing plasma rearrangement in the presence of static perturbing fields","authors":"T. Rubin, I. E. Ochs, N. J. Fisch","doi":"10.1063/5.0222129","DOIUrl":"https://doi.org/10.1063/5.0222129","url":null,"abstract":"Charged particles interacting with electromagnetic waves have a portion of their energy tied up in wave-driven oscillations. When these waves are localized to the exhaust of linear magnetic confinement systems, this ponderomotive effect can be utilized to enhance particle confinement. The same effect can be derived for particles moving via an E×B drift into a region of a static perturbation to the electromagnetic fields which has a large wave vector component in the direction of the motion. In this work, we use a simplified slab model to self-consistently solve for the electromagnetic fields within the fluid flowing plasma of a static flute-like (k∥=0) perturbation and evaluate the resulting ponderomotive potential. We find that two types of perturbations can exist within the flowing plasma, which are an O wave and an X wave in the frame moving with the fluid. In the case of tenuous plasma, these perturbations are magnetostatic or electrostatic multipole-analog perpendicular to the guiding magnetic field in the lab frame, respectfully. For denser plasmas, the O wave-like perturbation is screened at the electron skin depth scale, and the X wave-like perturbation is a combination of a similar perpendicular electric perturbation and parallel magnetic perturbation. The ponderomotive potential generated in the X wave-like case is gyrofrequency-dependent and can be used as either potential barriers or potential wells, depending on the direction of the flow velocity.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"112 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221899","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}

引用次数: 0

Self-generated magnetic fields in the hot spot of direct-drive cryogenic implosions at Omega 欧米茄直接驱动低温内爆热点中的自生磁场

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-22 DOI: 10.1063/5.0211922

C. A. Frank, A. Bose

{"title":"Self-generated magnetic fields in the hot spot of direct-drive cryogenic implosions at Omega","authors":"C. A. Frank, A. Bose","doi":"10.1063/5.0211922","DOIUrl":"https://doi.org/10.1063/5.0211922","url":null,"abstract":"This work reports that Biermann self-generated magnetic fields of ≈200 MG and Hall parameters of ≈1.5 are produced in the stagnation phase of direct-drive cryogenic implosions at Omega. The magnetic fields produce a drop of 2.4% in fusion yield and 1% in ion temperature. A quantitative estimate of the effect of self-generated magnetic fields on yield and ion temperature is essential, since direct measurements of these fields are not available. Reconstructed simulations of the 50 Gbar implosions, with all the stagnation measurements reproduced simultaneously by a combination of mid- and low-mode asymmetries as degradation mechanisms [Bose et al., Phys. Plasmas 25, 062701 (2018)], are used to obtain the estimates. The magnetic fields cause a decrease in yield due to the Righi–Leduc heat flow, which exceeds any benefits from heat flow suppression due to magnetization. It is important to note that both direct-drive Omega-scale implosions and indirect-drive National Ignition Facility (NIF)-scale implosions [Walsh et al., Phys. Rev. Lett. 118, 155001 (2017)] produce similar estimates for the magnetic field strength, and both show a decrease in fusion yield, with the Righi–Leduc transport as the loss mechanism. However, the yield degradation at Omega is small and lower by ≈5× compared to the indirect-drive ignition-scale NIF estimate.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"7 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221903","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}

引用次数: 0

Analysis of three-dimensional time-varying characteristics of subsonic plasma jet 亚音速等离子体射流的三维时变特性分析

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-22 DOI: 10.1063/5.0218607

Fei Ding, Yanming Liu, Jing Jia, Yixuan Li, Leiqin He, Weifeng Deng

{"title":"Analysis of three-dimensional time-varying characteristics of subsonic plasma jet","authors":"Fei Ding, Yanming Liu, Jing Jia, Yixuan Li, Leiqin He, Weifeng Deng","doi":"10.1063/5.0218607","DOIUrl":"https://doi.org/10.1063/5.0218607","url":null,"abstract":"The plasma jet wind tunnel, as a ground simulation device for studying the electromagnetic properties of near-space vehicle sheaths, can help people conduct several studies, such as communications and electronic parameter diagnostics. The plasma produced by a plasma generator has time-dependent variations due to the influence of power supply oscillations, turbulence, and other aspects of the device. To accurately define the experimental state of plasma, it is necessary to carefully analyze the three-dimensional (3D) time-varying characteristics of the plasma jet accurately since the distribution is non-uniform. This paper uses volume tomography technology to reconstruct the time series of the 3D emission field of the plasma jet with high-speed cameras. Then, the time–frequency characteristics, overall instability of the emission intensity, central axis position, and shape of the plasma jet are analyzed. The following characteristics are mainly observed: First, the plasma generator ejects plasma intermittently, which then spirals forward away from the nozzle. Second, the intensity, the radius of central axis movement, and the shape of the plasma jet vary with time at the same low frequency. The magnitude of this frequency is mainly related to the rate of change of the jet's air pressure difference with the vacuum chamber. Third, the overall instability of the plasma jet increases along the axial direction away from the nozzle and radially away from the center of the jet.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"25 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221901","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}

引用次数: 0

Simulation of hemispherical cathode-based linear plasma propulsion device upgrade 半球形阴极线性等离子体推进装置升级模拟

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-22 DOI: 10.1063/5.0191580

M. E. Abdel-kader

{"title":"Simulation of hemispherical cathode-based linear plasma propulsion device upgrade","authors":"M. E. Abdel-kader","doi":"10.1063/5.0191580","DOIUrl":"https://doi.org/10.1063/5.0191580","url":null,"abstract":"Electromagnetic plasma propulsion is generated by the linear plasma propulsion (LPP) apparatus. The LPP device is upgraded to operate and simulate at a maximum energy of 5.4 kJ. The cathode's cylindrical upper portion is changed into a hemispherical shape as part of the upgrading process to boost the current sheath (CS) acceleration. According to the model, the CS moves in the z-direction with a linear velocity while moving in the θ-direction with an angular velocity. When the plasma is squeezed and compressed, it is driven through the extension tube. The model describes the CS motion, its characteristics, and the propelled plasma using four phases: an axial, an angular radial, a reflected, and an expansion phases. The simulated Ith and experimental Iex current signals were compared to prove the validity of the model assumption, where the values of Ith and Iex were 89.7 and 88 kA, respectively. According to the results, as the motion angle increases in the angular radial phase, the CS compresses, elongates, and is forced into the extension tube. The results showed that the peaks of both plasma inductance, velocity, temperature, and propelled plasma length were 36.3 nH, 6.36 cm/μs, 6.72 eV, and 3.22 cm, respectively.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221900","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}

引用次数: 0