磁粘性流体中的模拟引力：吸积盘中的增强模拟霍金温度
Analog Gravity in Magneto-Viscous Fluids: Enhanced Analog Hawking Temperature in Accretion Disks
- Indian Institute of Science（印度科学研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出磁流体中的粘磁声学模拟引力框架，证明快磁声模式在吸积盘中可形成视界，且模拟霍金温度随磁场拓扑和粘性参数增强而升高。
AI中文摘要：
我们提出了一个用于磁流体动力学（MHD）流动中模拟引力的三维粘磁声学框架。虽然标准流体耗散通常会破坏声学度规的洛伦兹型符号，但我们证明，在eikonal极限下结合Shakura-Sunyaev $\alpha$-粘性方案评估波扰动，可以为快磁声模式保留一个定义良好的有效时空几何。慢磁声模式和Alfvén模式不允许存在非退化度规。为了研究模拟视界热力学，我们利用天体物理吸积盘作为背景介质，具体模拟了围绕旋转黑洞的数值磁化平流吸积流，以及解析的平流主导内流-外流解（ADIOS）。标准的自相似ADIOS模型严格强制恒定的马赫数，从而排除了视界的形成。因此，我们引入一个打破自相似性的磁场扰动，产生动态马赫数，并使粘磁声学视界的形成成为可能。通过评估这些视界处的自发声子发射，我们揭示了模拟霍金温度对磁场拓扑高度敏感；背景磁梯度的空间取向决定了霍金辐射是被放大还是被抑制。此外，我们发现增加粘性参数会导致模拟霍金温度单调增加。
英文摘要：
We present a three-dimensional visco-magnetoacoustic framework for analog gravity in magnetohydrodynamic (MHD) flows. While standard fluid dissipation typically breaks the Lorentzian signature of acoustic metrics, we demonstrate that evaluating wave perturbations in the eikonal limit alongside the Shakura-Sunyaev $α$-viscosity prescription preserves a well-defined effective spacetime geometry for the fast magnetoacoustic mode. The slow-magnetoacoustic mode and Alfvén mode do not admit a non-degenerate metric. To investigate analog horizon thermodynamics, we utilize astrophysical accretion disks as background media, specifically modeling numerical magnetized advective accretion flows around rotating black holes and analytical advection-dominated inflow-outflow solutions (ADIOS). Standard self-similar ADIOS models strictly enforce a constant Mach number, precluding horizon formation. We therefore introduce a magnetic field perturbation that breaks self-similarity, generates a dynamic Mach number, and enables the formation of a visco-magnetoacoustic horizon. By evaluating the spontaneous phonon emission at these horizons, we reveal that the analog Hawking temperature is highly sensitive to the magnetic field topology; the spatial orientation of the background magnetic gradients dictates whether the Hawking radiation is amplified or suppressed. Furthermore, we find that increasing the viscosity parameter leads to a monotonic increase in the analog Hawking temperature.
