天体物理中自组织临界现象的观测和模拟  

Observations and simulations of self-organized criticality phenomena in astrophysics

作　　者：李川 王文博 陈鹏飞 LI Chuan;WANG WenBo;CHEN PengFei(Key Laboratory for Modern Astronomy and Astrophysics,Ministry of Education,School of Astronomy and Space Science,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学天文与空间科学学院,现代天文与天体物理教育部重点实验室,南京210023

出　　处：《中国科学：物理学、力学、天文学》2022年第6期12-29,共18页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家重点研发计划(编号:2020YFC2201200);国家自然科学基金(编号:11673012,11961131002)资助项目。

摘　　要：自组织临界(Self-Organized Ciriticality,SOC)理论描述了一个非线性动力学系统或复杂系统在不依赖于外部参数调节的情况下,由能量驱动并通过自组织过程演化到某个临界点,随之产生无标度的、分形耗散的且满足幂律分布的能量释放现象.自其诞生之日起,SOC理论就被广泛地应用于解释诸多非线性动力学系统的幂律频数分布.本文概述了SOC系统能量释放的物理过程,总结了SOC在天体物理中的观测和模拟研究,讨论了SOC和MHD湍流在天体爆发活动中的作用,提出了SOC对空间天气预报可能的应用价值以及该领域中有待解决的一些重要问题.Self-organized criticality(SOC)is a critical state of a nonlinear dynamical system or a complex system that is continuously driven toward a critical value of instability threshold independent of external parameters,resulting in scalefree,fractal-diffusive,and intermittent avalanches or energy releases with power-law distributions.Since its introduction in 1987,the concept of SOC has been widely used to explain the power-law frequency distributions of nonlinear dynamical systems.We review the observations and simulations of SOC phenomena in astrophysics,identify the roles of SOC and MHD turbulence in producing astrophysical instabilities,and discuss potential applications of SOC in space weather as well as some critical challenges that must be addressed in the future.

关 键 词：自组织临界 等离子体湍流 太阳活动 

分 类 号：P14[天文地球—天体物理]