反应扩散系统中螺旋波的失稳

文章以反应扩散系统为例，介绍了在可激发系统与振荡系统中螺旋波产生、发展、演化的一些基本性质及规律，并讨论了作者近年来对螺旋波的各种失稳途径、时空混沌的产生机理及螺旋波控制方面所做的实验与理论工作，重点讨论了两类螺旋波失稳现象：爱克豪斯失稳与多普勒失稳，两类失稳都使系统从有规律的螺旋波态变为时空混沌（缺陷湍流）态。

SPIRAL INSTABILITIES IN A REACTION-DIFFUSION SYSTEM

Using a reaction-diffusion system as an example,we introduce the basic properties of spiral waves in excitable or oscillatory media,and discuss different routes that lead from an ordered spiral state to a chaotic state.First we present some basic properties of spiral dynamic,such as its emergence,development,and transition.Then we discuss our recent experimental results on the spiral instabilities of the Belosov-Zhabotinsky reaction in a quasi-two-dimensional reaction-diffusion system.Two routes leading to spatio-temporal turbulence have been observed in the experiments.Both of them can be characterized by defect-mediated-turbulence.The first instability is due to the Eckhaus instability,which generates defects at a distance from the spiral center because of its“convective”nature.The second instability creates defects in the spiral center.The mechanism of the instability is linked to the Doppler effect,when a Hopf bifurcation contributes to the spiral core,making the latter meandering.