Turbulence in classical fluids is characterized by persistent structures that emerge from the chaotic landscape. We investigate the analogous process in fully kinetic plasma turbulence by using high-resolution, direct numerical simulations in two spatial dimensions. We observe the formation of long-lived vortices with a profile typical of macroscopic, magnetically dominated force-free states. Inspired by the Harris pinch model for inhomogeneous equilibria, we describe these metastable solutions with a self-consistent kinetic model in a cylindrical coordinate system centered on a representative vortex, starting from an explicit form of the particle velocity distribution function. Such new equilibria can be simplified to a Gold–Hoyle solution of the modified force-free state. Turbulence is mediated by the long-lived structures, accompanied by transients in which such vortices merge and form self-similarly new metastable equilibria. This process can be relevant to the comprehension of various astrophysical phenomena, going from the formation of plasmoids in the vicinity of massive compact objects to the emergence of coherent structures in the heliosphere.

中文翻译：

---

动力学天体物理等离子体湍流中的长寿命平衡


经典流体中的湍流的特点是从混沌景观中出现的持久结构。我们通过在两个空间维度上使用高分辨率、直接数值模拟来研究全动态等离子体湍流中的类似过程。我们观察到长寿命涡旋的形成，其轮廓具有典型的宏观磁控无力状态。受非均匀平衡的 Harris 箍缩模型的启发，我们从粒子速度分布函数的显式形式开始，在以代表性涡旋为中心的圆柱坐标系中用自洽动力学模型描述这些亚稳态解。这种新的平衡可以简化为修改后的无力状态的戈德-霍伊尔解。湍流是由长寿命结构介导的，伴随着瞬态，其中这些涡流合并并形成自相似的新亚稳态平衡。这个过程可能与理解各种天体物理现象有关，从巨大致密天体附近等离子体团的形成到日光层中相干结构的出现。