具有随机加热的膨胀磁管中分层等离子体的无碰撞稳态
Collisionless stationary states of a stratified plasma in an expanding magnetic tube with stochastic heating
- LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS（巴黎天文台，PSL大学，索邦大学，巴黎西岱大学，塞吉-蓬图瓦兹大学，法国国家科学研究中心）
- Mullard Space Science Laboratory, University College London（穆拉德空间科学实验室，伦敦大学学院）
- Ruhr University Bochum（波鸿鲁尔大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
研究存在膨胀磁场时太阳上层大气的无碰撞动力学结构，从弗拉索夫方程推导相关解析表达式，分析能量和磁矩守恒等产生的影响，给出标度律并验证，为研究磁场膨胀对弱碰撞恒星日冕结构的作用建立理论框架。
AI中文摘要：
我们研究了存在膨胀磁场时太阳上层大气的无碰撞动力学结构。考虑了一种静止的双组分等离子体，它被限制在一个膨胀的磁通管内，受到重力、自静电相互作用、潘内科克 - 罗斯兰电场和磁矩守恒的影响。从弗拉索夫方程出发，我们推导出了粒子分布函数、密度剖面以及平行、垂直和总温度剖面的完全解析表达式。我们表明，能量和磁矩的联合守恒产生了损失锥分布，相对于相应的未磁化大气降低了密度，并产生了明显的温度各向异性。对于单温度边界条件，磁矩守恒和重力之间的竞争导致平行温度出现最大值。我们推导了其位置和幅度的解析标度律，并通过数值计算进行了验证。我们还表明，各向异性与下边界的温度分布无关。在罕见但强烈的加热事件 regime 中，引力过滤增强了日冕高度最热粒子群体的贡献，而磁矩守恒进一步放大了由此产生的速度空间各向异性。这项工作提供了一个完全解析的动力学描述，用于描述在底部经历随机加热的膨胀日冕磁通管中引力过滤和磁矩守恒的联合效应。这些结果为研究磁场膨胀在塑造弱碰撞恒星日冕的密度和温度结构中的作用建立了一个理论框架。
英文摘要：
We investigate the collisionless kinetic structure of the upper solar atmosphere in an expanding magnetic field. Building on established velocity-filtration models, we extend the stochastic multi-temperature framework developed in previous works by including magnetic-field expansion and magnetic-moment conservation. Stochastic heating generates a non-Maxwellian boundary distribution through the superposition of particle populations associated with different temperatures. We consider a stationary two-component plasma confined within an expanding magnetic flux tube and subject to gravity, self-consistent electrostatic interactions, the Pannekoek--Rosseland electric field, and magnetic-moment conservation. Starting from the Vlasov equation, we derive fully analytical expressions for the distribution functions, density, and parallel, perpendicular, and total temperature profiles. The combined conservation of energy and magnetic moment generates a loss-cone distribution, reducing the density relative to the unmagnetized case and producing temperature anisotropy. For a single-temperature boundary, the competition between gravity and magnetic-moment conservation produces a maximum in the parallel temperature, for which we derive and numerically validate analytical scaling laws. With stochastic heating, gravitational filtering enhances the contribution of hotter populations at coronal heights, while magnetic-moment conservation amplifies the velocity-space anisotropy. Our analytical solution provides a collisionless benchmark for future kinetic models incorporating more realistic magnetic-field geometries, Coulomb collisions, and turbulent particle scattering.
