发表机构
Ruhr-Universität Bochum; KU Leuven; University College London; University of Arizona（波鸿鲁尔大学; 荷语鲁汶大学; 伦敦大学学院; 亚利桑那大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文首次采用规则化Kappa分布（RKD）结合ALPS求解器研究空间等离子体中斜向消防水带不稳定性，验证了超热粒子对增长率的增强作用，并揭示了RKD在高斜向传播时对非周期性模式的显著影响。
AI 中文摘要
空间等离子体的原位测量表明，带电粒子的速度分布并不处于热平衡状态，由于各向异性和超热粒子群体增强了高能尾部，其偏离标准麦克斯韦分布。尽管标准Kappa分布（SKD）在模拟这些非平衡分布方面已得到广泛应用，但由于其某些非物理的推论，特别是速度矩发散问题，其应用常引发争议。为解决这些问题，引入了规则化Kappa分布（RKD）。本文首次采用这种先进的、通常具有各向异性的RKD来研究斜向消防水带不稳定性，包括由电子和质子（空间等离子体中的主要成分）的温度各向异性所引发的不稳定性。在弱碰撞等离子体中，这两种不稳定性预计在空间等离子体（如膨胀的太阳风）宏观性质的自调节中发挥重要作用，这与观测结果一致。目前尚无法借助与RKD等离子体相关的一般色散张量（其推导仍具挑战性），因此本文采用了任意线性等离子体求解器（ALPS）。针对已建立的麦克斯韦分布和SKD获得的不稳定解成功验证了ALPS的能力。对于RKD，不稳定性证实了超热粒子群体的激发效应，较低的Kappa值通常会增强消防水带增长速率。对于斜向电子消防水带不稳定性，RKD仅在中等角度下显著改变周期性与非周期性分支之间的竞争，并且在高斜向传播时能够维持显著增加的增长速率，尤其是非周期性模式，其增长速率超越了麦克斯韦不稳定区域以及SKD可达到的范围。
英文摘要
In-situ measurements in space plasmas indicate that the velocity distributions of charged particles are not in thermal equilibrium, deviating from a standard Maxwellian mainly due to anisotropies and suprathermal populations which enhance high-energy tails. Although the Standard \k{appa}-Distribution (SKD) is well established in modeling these non-equilibrium distributions, its application is often viewed controversially due to certain unphysical implications, in particular divergent velocity moments. To address these issues, the Regularized \k{appa}-Distribution (RKD) was introduced. Such advanced, in general anisotropic RKDs are invoked here for the first time to investigate oblique firehose instabilities, including those induced by the temperature anisotropy of electrons and protons, the dominant species in space plasmas. In weakly collisional plasmas, both of these instabilities are expected to play significant roles in the self-regulation of the macroscopic properties of space plasmas (e.g. the expanding solar wind) reported by observations. Is not yet possible to resort to a general dispersion tensor related to RKD plasmas (whose derivation is still a challenge), instead the Arbitrary Linear Plasma Solver (ALPS) is exploited here. The unstable solutions obtained for the already established Maxwellian & SKDs successfully validate the capability of ALPS. For RKDs, the instabilities confirm the stimulating effect of suprathermal populations, with lower \k{appa} values generally enhancing the firehose growth rates. For the oblique electron firehose instability, RKDs substantially modify the competition between periodic & aperiodic branches only at intermediate angles & can sustain significantly increased growth rates of especially aperiodic modes at highly oblique propagation beyond both the Maxwellian unstable regime & the one that is accessible with SKDs.
CommentsAccepted for publication in Journal of Plasma Physics, 24 pages, 11 figures, 3 tables
