论文标题
通过磁内培养基中的磁性泵的加热机构
A Heating Mechanism via Magnetic Pumping in the Intracluster Medium
论文作者
论文摘要
由AGN活性，聚类合并和星系运动驱动的湍流构成了加热簇内培养基（ICM）的有吸引力的能源。鉴于其低碰撞和高磁化强度（排除库仑工艺的粘性加热），这种能量如何散入ICM等离子体尚不清楚。 Kunz等。 2011年提出了一种基于在ICM条件下血浆压力（陀螺仪加热）各向异性的可行加热机制。目前的论文建立在这项工作的基础上，并表明颗粒可以通过磁性抽水大规模的湍流波动来旋转。我们研究各向异性如何在一系列强迫频率，生成的波和不稳定性下演变，并证明颗粒分布函数可获得高能量尾巴。为此，我们执行粒子中的模拟，在其中定期改变平均磁场$ \ textbf {b}（t）$。当$ \ textbf {b}（t）$生长（少量）时，压力各向异性$ p _ {\ perp}> p _ {\ parallel} $（$ p _ {\ perp} <p _ {\ p _ {\ parallel} $}分别是垂直的压力，并平行于$ \ textbf {b}（t）$）。这些压力各向异性激发镜子（$ p _ {\ perp}> p _ {\ parallel} $）和倾斜的firehose（$ p _ {\ parallel}> p _ {\ perp} $）的不稳定性，它们会困扰和散布颗粒，散布粒子，并限制了频道，并为plas and plas s the plas note the plas andmam clastema。该机制的效率取决于大规模湍流波动的频率以及不稳定性在其非线性阶段提供的散射效率。我们提供了一个简化的分析加热模型，可捕获所涉及的现象学。我们的结果表明，此过程可能与ICM动力学尺度的耗散和分布湍流能量有关。
Turbulence driven by AGN activity, cluster mergers and galaxy motion constitutes an attractive energy source for heating the intracluster medium (ICM). How this energy dissipates into the ICM plasma remains unclear, given its low collisionality and high magnetization (precluding viscous heating by Coulomb processes). Kunz et al. 2011 proposed a viable heating mechanism based on the anisotropy of the plasma pressure (gyroviscous heating) under ICM conditions. The present paper builds upon that work and shows that particles can be gyroviscously heated by large-scale turbulent fluctuations via magnetic pumping. We study how the anisotropy evolves under a range of forcing frequencies, what waves and instabilities are generated and demonstrate that the particle distribution function acquires a high energy tail. For this, we perform particle-in-cell simulations where we periodically vary the mean magnetic field $\textbf{B}(t)$. When $\textbf{B}(t)$ grows (dwindles), a pressure anisotropy $P_{\perp}>P_{\parallel}$ ($P_{\perp}< P_{\parallel}$) builds up ($P_{\perp}$ and $P_{\parallel}$ are, respectively, the pressures perpendicular and parallel to $\textbf{B}(t)$). These pressure anisotropies excite mirror ($P_{\perp}>P_{\parallel}$) and oblique firehose ($P_{\parallel}>P_{\perp}$) instabilities, which trap and scatter the particles, limiting the anisotropy and providing a channel to heat the plasma. The efficiency of this mechanism depends on the frequency of the large-scale turbulent fluctuations and the efficiency of the scattering the instabilities provide in their nonlinear stage. We provide a simplified analytical heating model that captures the phenomenology involved. Our results show that this process can be relevant in dissipating and distributing turbulent energy at kinetic scales in the ICM.
