Fundamental Plasma Physics最新文献

英文中文

Spherical nonthermal pulsational mode stability thermo-statistically moderated with extra-negative ions 球面非热脉动模式稳定性与额外的负离子热统计缓和

Fundamental Plasma Physics

Pub Date : 2025-06-01 Epub Date: 2025-02-26 DOI: 10.1016/j.fpp.2025.100087

Jonmoni Dutta , Ahmed Atteya , Pralay Kumar Karmakar

The presence of diverse negative ions is well-known to modify different collective waves and instabilities in diverse space and astrophysical environments. We herein investigate the stability dynamics of the spherical nonthermal (kappa-modified) pulsational mode of gravitational collapse (PMGC) excitable in astrophysical dust molecular clouds (DMCs). It primarily explores the impact of the realistic nonthermal negative ionic effects on the PMGC stability features. The high-energetic lighter constituents, such as the electrons, positive ions, and negative ions, are modelled with their respective nonthermal kappa (

κ

)-distribution laws. The inertial dust particulates are treated in the viscous fluid fabric. Application of spherical normal mode treatment results in a generalized linear quartic (degree-4) dispersion relation. A computational illustrative platform illuminates the underlying stabilizing and destabilizing factors. It is seen that the cloud size, dust mass, dust charge, nonthermality parameters, equilibrium charged dust number density, and neutral dust viscosity play stabilizing roles. It counters the destabilizing scenarios caused by the equilibrium electron number density, positive ion number density, negative ion number density, neutral dust density, and charged dust viscosity. The fundamental physical mechanisms responsible herein are substantiated and compared in light of the previous predictions. The nontrivial avenues of our study in realizing the Jeans-driven galactic structural unit formation processes, moderated actively with the presence of negative ions in diverse real astronomical circumstances are summarily indicated.

众所周知，在不同的空间和天体物理环境中，不同负离子的存在会改变不同的集体波和不稳定性。本文研究了天体物理尘埃分子云（DMCs）中可激发的球形非热（kappa修正）引力坍缩（PMGC）脉动模式的稳定性动力学。主要探讨了实际非热负离子效应对PMGC稳定性特性的影响。高能量较轻的组分，如电子、正离子和负离子，用它们各自的非热kappa （κ）分布规律进行建模。惯性粉尘颗粒在粘性流体结构中进行处理。应用球面正模处理得到广义线性四次（4次）色散关系。计算说明平台阐明了潜在的稳定和不稳定因素。可见，云量、粉尘质量、粉尘电荷、非热性参数、平衡带电尘数密度和中性尘粘度均起稳定作用。它抵消了由平衡电子数密度、正离子数密度、负离子数密度、中性粉尘密度和带电粉尘粘度引起的不稳定情况。根据先前的预测，本文证实并比较了其中的基本物理机制。摘要指出了我们在实现jean驱动的星系结构单元形成过程中的非平凡研究途径，这些过程在各种实际天文环境中受到负离子的积极调节。

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引用次数: 0

Revealing noncanonical Hamiltonian structures in relativistic fluid dynamics 揭示相对论流体动力学中的非正则哈密顿结构

Fundamental Plasma Physics

Pub Date : 2025-06-01 Epub Date: 2025-04-29 DOI: 10.1016/j.fpp.2025.100092

Keiichiro Takeda , Naoki Sato

We present the noncanonical Hamiltonian structure of the relativistic Euler equations for a perfect fluid in Minkowski spacetime. By identifying the system’s noncanonical Poisson bracket and Hamiltonian, we show that relativistic fluid flows preserve helicity and enstrophy as conserved quantities in three-dimensional and two-dimensional cases, respectively. This holds when the fluid follows a relativistic

γ

-barotropic equation of state, which generalizes the classical barotropic condition. Furthermore, we demonstrate that these conserved quantities are Casimir invariants associated with the noncanonical Poisson structure. These findings open new avenues for applying Hamiltonian theory to the study of astrophysical fluids and relativistic plasmas.

我们给出了闵可夫斯基时空中完美流体的相对论欧拉方程的非正则哈密顿结构。通过识别系统的非正则泊松括号和哈密顿量，我们证明了相对论性流体流动分别在三维和二维情况下保持螺旋度和熵作为守恒量。当流体遵循相对论性γ-正压状态方程时，这一点成立，它推广了经典的正压条件。此外，我们证明了这些守恒量是与非正则泊松结构相关的卡西米尔不变量。这些发现为将哈密顿理论应用于天体物理流体和相对论等离子体的研究开辟了新的途径。

引用次数: 0

Generation of mega-gauss axial and azimuthal magnetic fields in a solid plasma by ultrahigh intensity, circularly polarized femtosecond laser pulses 用超高强度圆偏振飞秒激光脉冲在固体等离子体中产生兆高斯轴向和方位磁场

Fundamental Plasma Physics

Pub Date : 2025-06-01 Epub Date: 2025-03-13 DOI: 10.1016/j.fpp.2025.100088

Anandam Choudhary , Laxman Prasad Goswami , C. Aparajit , Amit D. Lad , Ameya Parab , Yash M. Ved , Trishul Dhalia , Amita Das , G. Ravindra Kumar

The interaction of intense linearly polarized (LP) femtosecond laser pulses with solids is known to generate azimuthal magnetic fields, while circularly polarized (CP) light has been shown to create axial fields. We demonstrate through experiments and particle-in-cell simulations that circularly polarized light can generate both axial and azimuthal fields of comparable magnitude in a plasma created in a solid. Angular distributions of the generated fast electrons at the target front and rear show significant differences between the results for the two polarization states, with circular polarization enforcing more axial confinement. The measurement of the spatial distribution of both types of magnetic fields captures their turbulent evolution.

强线偏振（LP）飞秒激光脉冲与固体的相互作用已知会产生方位磁场，而圆偏振（CP）光已被证明会产生轴向磁场。我们通过实验和细胞内粒子模拟证明，圆偏振光可以在固体中产生的等离子体中产生相当大小的轴向和方位场。在两种极化状态下，产生的快电子在目标前后的角分布有显著差异，圆极化对轴向约束作用更强。测量这两种磁场的空间分布可以捕捉到它们的湍流演化。

引用次数: 0

High energy gain of ion-driven flux compression in cylindrical target with initial power-law radial density profile 具有初始幂律径向密度分布的圆柱形目标中离子驱动通量压缩的高能量增益

Fundamental Plasma Physics

Pub Date : 2025-03-01 Epub Date: 2025-01-03 DOI: 10.1016/j.fpp.2025.100085

Soheil Khoshbinfar

The magnetized target fusion (MTF) concept is considered an economic way to harness fusion energy that resides between two ICF and MCF pathways. Here, we have proposed a new DT fuel initial density profile that improves final fusion yield in cylindrical targets in MTF. We have employed the Deira-4 MHD code to investigate the performance of these configurations. The potential advantage of an initial density gradient over a common uniform profile assumption in inertial fusion energy is its higher energy gain at the cost of lower input driver energy. It was shown that its energy gain is higher by a factor of two and reduction in driver input energy by a factor of three for a fixed DT fuel mass regime, m_DT∼2.2 mg. The radial density profile of DT fuel also promises to make larger targets that work at a sub-MJ regime which resolves our concern about the Rayleigh-Taylor instability growth rate during the implosion phase. It has also been shown that the best results with a seed axial magnetic field ∼10 T would be achieved for a power-law density profile, ρ∝rⁿ, with an exponent n=3. Moreover, the optimal target geometry attains for initial aspect ratio of ∼15 and ignition threshold reduced from <ρR>_DT,th=0.56 g/cm² in uniform density of DT fuel to the power law density profile of ρ∝r³ to <ρR>_DT,th =0.21 g/cm².

磁化靶聚变（MTF）的概念被认为是利用两个ICF和MCF途径之间的聚变能量的一种经济方法。在这里，我们提出了一种新的DT燃料初始密度分布，提高了MTF中圆柱形目标的最终聚变产率。我们使用Deira-4 MHD代码来研究这些配置的性能。在惯性聚变能量中，初始密度梯度相对于普通均匀轮廓假设的潜在优势是它以较低的输入驱动能量为代价获得较高的能量增益。结果表明，对于固定DT燃料质量体系（mDT ~ 2.2 mg），其能量增益增加了两倍，驱动器输入能量减少了三倍。DT燃料的径向密度分布也有望在亚mj状态下制造更大的目标，这解决了我们对内爆阶段瑞利-泰勒不稳定增长率的担忧。研究还表明，对于幂律密度曲线ρ∝rn，指数n=3，当种子轴向磁场为~ 10 T时，可以获得最佳结果。此外，在初始长径比为~ 15和点火阈值从均匀密度的DT燃料的ρ∝r3的ρ ρ r>；DT,th=0.56 g/cm2降低到幂律密度曲线ρ∝r3到ρ lt；ρ r>；DT,th= 0.21 g/cm2时的最佳目标几何形状。

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引用次数: 0

Radiative damping of toroidal Alfvén eigenmode in low-shear plasmas 低剪切等离子体环面alfv<s:1>本征模的辐射阻尼

Fundamental Plasma Physics

Pub Date : 2025-03-01 Epub Date: 2025-02-02 DOI: 10.1016/j.fpp.2025.100086

B.N. Breizman , S.E. Sharapov

Instabilities of Alfvén eigenmodes (AEs) are of significant concern because they can enhance the cross-field transport of fusion-born alpha particles beyond the neoclassical level in magnetic fusion plasmas. The threshold value of alpha-particle pressure for exciting AEs depends critically on the damping rate of AEs. The damping mechanisms include kinetic damping due to interactions with thermal particles, continuum damping due to AE frequency crossing Alfvén continuum, and radiative damping due to emitting kinetic Alfvén waves (KAWs). The radiative damping is substantial and can even prevail in high-temperature burning plasmas [1]. We revisit the radiative damping analytic theory for TAE in plasmas with low positive magnetic shear, considering TAE with an eigenfrequency near the bottom of TAE-gap and with poloidal harmonics of the same sign (even TAE). In contrast to earlier papers, we provide the damping calculations in real space rather than Fourier space. This approach is straightforward technically and more enlightening from a physics standpoint for benchmarking numerical calculations of radiative damping. The parametric dependence of the resulting damping rate agrees with that of Refs. [2-5], but it has a smaller numerical factor in front of it.

在磁融合等离子体中，由于α - δ δ δ的不稳定性可以使聚变产生的α粒子的跨场输运提高到新经典水平，因此引起了人们的广泛关注。激发AEs的α粒子压力阈值主要取决于AEs的阻尼率。阻尼机制包括与热粒子相互作用产生的动能阻尼、声发射频率跨越alfv 连续体产生的连续阻尼和发射动能alfv 波（kaw）产生的辐射阻尼。辐射阻尼是巨大的，甚至可以在高温燃烧等离子体b[1]中普遍存在。我们重新研究了低正磁剪切等离子体中TAE的辐射阻尼分析理论，考虑TAE具有接近TAE间隙底部的特征频率和具有相同符号的极向谐波（甚至TAE）。与以前的论文相比，我们提供了在真实空间而不是傅里叶空间中的阻尼计算。这种方法在技术上是直接的，从物理的角度来看，对辐射阻尼的基准数值计算更具启发性。所得阻尼率的参数依赖性与Refs一致。[2-5]，但它前面有一个较小的数值因子。

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引用次数: 0

N-body simulation of spinning particle pairs in a complex plasma crystal 复杂等离子体晶体中自旋粒子对的n体模拟

Fundamental Plasma Physics

Pub Date : 2025-03-01 Epub Date: 2024-12-06 DOI: 10.1016/j.fpp.2024.100082

Zachary Watson , Parker Adamson , Jorge Martinez-Ortiz , Katrina Vermillion , Calvin Carmichael , Samuel Garcia-Rodriguez , Lorin Matthews , Truell Hyde , Bryant Wyatt

Complex plasma, consisting of ionized gas mixed with micron-sized dust particles, exhibit unique behaviors due to the mass disparity between dust grains and other plasma components. These disparities result in non-Hamiltonian dynamics that pose significant challenges for numerical modeling. Under specific conditions, the dust grains self-organize into crystal structures, driven by ion wakefields and subject to imperfections that induce dynamic phenomena like torsions—where dust grains couple and exhibit elliptical motion within the crystal lattice.

To better understand these phenomena, we developed a near real-time interactive computer model grounded in laboratory conditions, specifically replicating the environment within a GEC RF reference cell. This model addresses the challenges of stiffness in differential equations by employing an innovative point charge approach, where each point charge is dynamically influenced by all dust grains, enhancing the model's accuracy and responsiveness. The system allows for user interaction, enabling the manipulation of parameters and near real-time observation of dust behavior. Our approach balances computational efficiency with the ability to simulate complex plasma dynamics, providing a powerful tool for the study of dusty plasma crystals.

复杂等离子体是由电离气体和微米级尘埃颗粒混合而成，由于尘埃颗粒和其他等离子体成分之间的质量差异而表现出独特的行为。这些差异导致了非哈密顿动力学，对数值模拟提出了重大挑战。在特定条件下，在离子尾流场的驱动下，尘埃颗粒自组织成晶体结构，并受到不完美的影响，从而诱发诸如扭转之类的动态现象——尘埃颗粒在晶格内相互作用并表现出椭圆运动。为了更好地理解这些现象，我们开发了一个基于实验室条件的近实时交互式计算机模型，专门复制GEC射频参考单元内的环境。该模型通过采用创新的点电荷方法解决了微分方程中刚度的挑战，其中每个点电荷都受到所有尘埃颗粒的动态影响，从而提高了模型的准确性和响应性。该系统允许用户交互，使参数的操作和近实时观察粉尘的行为。我们的方法平衡了计算效率和模拟复杂等离子体动力学的能力，为研究尘埃等离子体晶体提供了强大的工具。

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引用次数: 0

Solution of the linear wave-particle kinetic equation for global modes of arbitrary frequency in a tokamak 托卡马克中任意频率全局模态线性波粒动力学方程的解

Fundamental Plasma Physics

Pub Date : 2025-03-01 Epub Date: 2025-01-02 DOI: 10.1016/j.fpp.2025.100084

M. Fitzgerald , B.N. Breizman

The linear response of a plasma to perturbations of arbitrary frequency and wavelength is derived for any axisymmetric magnetized toroidal plasma. An explicit transformation to action-angle coordinates is achieved using orthogonal magnetic coordinates and the Littlejohn Lagrangian, establishing the validity of this result to arbitrary order in normalized Larmor radius. The global resonance condition for compressional modes is clarified in more detail than in previous works, confirming that the poloidal orbit-average of the cyclotron frequency gives the desired result at lowest order in Larmor radius. The global plasma response to the perturbation at each resonance is captured by a poloidal and gyroaverage of the perturbing potential. A “global gyroaveraging” of the potential is a natural by-product of this analysis which takes into account the changing of the magnetic field over an orbit. The resonance condition depends on two arbitrary integers which completely separately capture the effects poloidal non-uniformity and finite Larmor radius in generating sidebands. We learn that poloidal sidebands generated for compressional modes are dominated by the change in gyrofrequency over the orbit, which is very different to shear modes where the gyrofrequency only contributes via a finite Larmor radius effect. This increases the number of bounce harmonics required to compute the linear drive, giving a more complicated resonance map. An example calculation is given comparing resonance of shear and compressional modes in a published DIII-D case.

导出了任意轴对称磁化环形等离子体对任意频率和波长扰动的线性响应。利用正交磁坐标和利特尔约翰拉格朗日量实现了对作用角坐标的显式变换，建立了该结果在归一化拉莫尔半径下任意阶的有效性。与以往的研究相比，本文更详细地阐明了压缩模态的全局共振条件，证实了回旋加速器频率的极向轨道平均在拉莫尔半径的最低阶上给出了期望的结果。在每个共振中，等离子体对扰动的整体响应被摄动电位的极向和陀螺平均捕获。考虑到磁场在轨道上的变化，这种分析的自然副产品是对势的“全球陀螺平均”。共振条件取决于两个任意整数，这两个整数完全独立地捕获了极向非均匀性和有限拉莫尔半径在产生边带中的影响。我们了解到，压缩模态产生的极向侧带是由陀螺频率在轨道上的变化决定的，这与剪切模态非常不同，剪切模态的陀螺频率只通过有限的拉莫尔半径效应起作用。这增加了计算线性驱动所需的反弹谐波的数量，给出了更复杂的谐振图。在已发表的DIII-D案例中，给出了剪切模态和压缩模态共振的计算实例。

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引用次数: 0

Ultra-high charge electron acceleration for nuclear applications 用于核应用的超高电荷电子加速器

Fundamental Plasma Physics

Pub Date : 2024-12-01 Epub Date: 2024-08-30 DOI: 10.1016/j.fpp.2024.100071

Liming Chen, Jie Feng, Wenchao Yan, Hao Xu, Yaojun Li, Wenzhao Wang, Xulei Ge, Xiaojun Huang, Jie Zhang

Ultra-intense laser-plasma wakefield accelerator possess several superior properties compared with the traditional radio-frequency accelerators. These characteristics include femtosecond duration, micro-source size, and ultra-dense beam density, result in highly advantageous for various important applications. In this paper, we reviewed the generation of ultra-intense and high charge electron beam based on laser-plasma acceleration and its nuclear applications in Shanghai Jiao Tong University, including the production of 10 s nC charge beams, the generation of ultra-high flux neutron source on the order of 10¹⁹ n/cm²/s, and the excitation of nuclear isomers with the peak efficiency on the order of 10¹⁵ particle/s. This laser driving ultra-dense electron source, in conjunction with the plasma environment, presents immense potential in addressing critical problems in astrophysics, and facilitating various nuclear applications. Based on above progress in nuclear astrophysics, a new research plateform about laboratory astrophysics with a 2.5 PW laser will be constructed in TDLI institute.

与传统的射频加速器相比，超强激光等离子体唤醒场加速器具有多种优越性能。这些特性包括飞秒持续时间、微源尺寸和超密集电子束密度，因此在各种重要应用中具有极大的优势。本文综述了上海交通大学基于激光等离子体加速技术的超强高电荷电子束的产生及其在核领域的应用，包括产生10 s nC电荷束、产生1019 n/cm2/s数量级的超高通量中子源，以及以1015粒子/s数量级的峰值效率激发核异构体。这种激光驱动的超密集电子源与等离子体环境相结合，在解决天体物理学的关键问题和促进各种核应用方面具有巨大潜力。在核天体物理学取得上述进展的基础上，将在 TDLI 研究所建造一个配备 2.5 PW 激光器的实验室天体物理学研究平台。

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引用次数: 0

Early applications of Neural Networks to plasma science: Architectures, solutions, and impact. 神经网络在等离子科学中的早期应用：架构、解决方案和影响。

Fundamental Plasma Physics

Pub Date : 2024-12-01 Epub Date: 2024-10-24 DOI: 10.1016/j.fpp.2024.100077

Savino Longo

Many applications of Neural Networks (NN) to plasma science have appeared in the last years. The author describes here some of the early applications of NNs to plasma science at the beginning of the 90 s, when multi-layer, feed-forward-back-propagation (FFBP) architectures found several applications in this field: they were used to solve inversion problems, to create complete sets of input data, to replace time-consuming modules in models and to predict the outcome of real processes. From a partially personal perspective the author reviews the details of plasma problems to which NNs were successfully applied, and those of the related architectures. It turns out that some solutions, which are perceived today as marking the difference between the previous and contemporary NNs application practices, were in common use >30 years ago when they were deemed fruitful. This can help create deeper historical insight into a field that is getting much attention today.

近年来，等离子体科学领域出现了许多神经网络（NN）应用。作者在此描述了 90 年代初神经网络在等离子体科学中的一些早期应用，当时多层前馈-后向传播（FFBP）架构在该领域有多种应用：它们被用于解决反演问题、创建完整的输入数据集、替代模型中耗时的模块以及预测实际过程的结果。作者从部分个人角度回顾了成功应用 NN 的等离子体问题的细节，以及相关架构的细节。结果发现，一些今天被视为标志着以前和当代 NNs 应用实践之间差异的解决方案，在 30 年前被认为富有成效时却已被普遍使用。这有助于对当今备受关注的领域进行更深入的历史洞察。

引用次数: 0

Ionospheric plasma irregularities over Dronning Maud Land in Antarctica and associated space weather effects 南极洲德龙宁毛德地上空电离层等离子体不规则现象及相关空间气象效应

Fundamental Plasma Physics

Pub Date : 2024-12-01 Epub Date: 2024-10-24 DOI: 10.1016/j.fpp.2024.100076

Wojciech J. Miloch, Daria S. Kotova, Yaqi Jin

Ionospheric plasma irregularities and associated space weather effects over Dronning Maud Land in Antarctica are studied with a multi-instrument approach. It is demonstrated during a substorm event that auroral particle precipitation associated with the edges of auroral arcs can lead to irregularities in the ionospheric plasma density that can have significant impact on trans-ionospheric radio waves. Both refractive and diffractive effects are observed on signals from the GNSS satellites, where the latter are identified by the ionospheric free linear combination approach and amplitude scintillation. Thus, intense auroral particle precipitation can lead to plasma irregularities at scales from several kilometers down to and below the Fresnel radius, and they can result in space weather effects which can lead to losing the integrity of the GNSS signals.

采用多仪器方法研究了南极洲德龙宁毛德地上空电离层等离子体的不规则性和相关的空间气象效应。结果表明，在一次亚暴事件中，与极光弧边缘有关的极光粒子沉降会导致电离层等离子体密度不规则，从而对跨电离层无线电波产生重大影响。在来自全球导航卫星系统卫星的信号上观察到折射和衍射效应，后者是通过电离层自由线性组合方法和振幅闪烁来识别的。因此，强烈的极光粒子沉降会导致等离子体不规则，其范围从几千米到菲涅尔半径及以下，它们会导致空间气象效应，从而失去全球导航卫星系统信号的完整性。

引用次数: 0

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