On the chaotic nature of solar-terrestrial environment: Interplanetary Alfvén intermittency

摘要

We present an overview of observational and theoretical evidence of chaos and intermittency in the solar-terrestrial environment including solar dynamo, solar atmosphere, solar wind, and terrestrial magnetosphere-ionosphere-atmosphere. The chaotic nature of space plasmas is studied by a nonlinear model of Alfvén waves described by the low-dimensional limit of the derivative nonlinear Schr?dinger equation given by its stationary solutions in the frame moving with the driver wave velocity. A periodic window of the bifurcation diagram is constructed to identify two types of Alfvén chaos related to type-I intermittency and crisis-induced intermittency. We show that an Alfvén chaotic attractor is composed of chaotic saddles and unstable periodic orbits and explain the links between these unstable structures and Alfvén intermittency. The role of interplanetary Alfvén intermittency in the solar wind driving of intense geomagnetic activities is discussed.