标题： 宇宙射线驱动的发电机效应下磁场演化的全球模拟 显示英文标题

标题： Global simulations of the magnetic field evolution under the influence of the cosmic-ray-driven dynamo

摘要： 我们展示了螺旋星系中宇宙射线（CR）驱动的发电机的三维全局数值模拟。 我们研究了在势的非轴对称成分（即棒）存在的情况下，螺旋星系星际介质的演化。 磁流体动力学发电机由宇宙射线驱动，这些宇宙射线由超新星（SN）遗迹持续供应到盘中。 模拟开始时没有磁场，但十分之一的超新星爆炸是小尺度随机取向偶极磁场的来源。 在所有模型中，我们假设10%的10^51 erg超新星动能输出转化为宇宙射线能量。 为了直接与星系的观测特性进行比较，我们构建了偏振射电发射的真实地图。 主要结果是，宇宙射线驱动的发电机可以在几吉年的时间内将弱磁场增强到几{\mu }G。 获得的倍增时间等于3亿年，磁场在时间t ~ 4.0 Gyr时达到能量平衡。 最初，完全随机的磁场演变为大尺度结构。 相对于银河平面，可以观察到磁场所具有的偶（四极子型）配置。 此外，建模的磁场配置类似于螺旋星系中观测到的偏振强度图。 偏振矢量沿着棒和旋臂之间分布。 此外，在整个模拟时间内，观察到磁臂相对于气体密度分布中的旋臂图案发生漂移。 显示英文摘要

摘要： We present three-dimensional global numerical simulations of the cosmic-ray (CR) driven dynamo in barred galaxies. We study the evolution of the interstellar medium of the barred galaxy in the presence of non-axisymmetric component of the potential, i.e., the bar. The magnetohydrodynamical dynamo is driven by CRs, which are continuously supplied to the disk by supernova (SN) remnants. No magnetic field is present at the beginning of simulations but one-tenth of SN explosions is a source of a small-scale randomly oriented dipolar magnetic field. In all models we assume that 10% of 10^51 erg SN kinetic energy output is converted into CR energy. To compare our results directly with the observed properties of galaxies, we construct realistic maps of polarized radio emission. The main result is that the CR-driven dynamo can amplify weak magnetic fields up to a few {\mu}G within a few Gyr in barred galaxies. The obtained e-folding time is equal to 300 Myr and the magnetic field reaches equipartition at time t ~ 4.0 Gyr. Initially, the completely random magnetic field evolves into large-scale structures. An even (quadrupole-type) configuration of the magnetic field with respect to the galactic plane can be observed. Additionally, the modeled magnetic field configuration resembles maps of the polarized intensity observed in barred galaxies. Polarization vectors are distributed along the bar and between spiral arms. Moreover, the drift of magnetic arms with respect to the spiral pattern in the gas density distribution is observed during the entire simulation time.