France-Japan Magnetic Fusion Laboratory, LIA 336 CNRS, Marseille, France.
Phys Rev Lett. 2009 Oct 2;103(14):145001. doi: 10.1103/PhysRevLett.103.145001. Epub 2009 Sep 29.
The nonlinear dynamics of magnetic tearing islands imbedded in a pressure gradient driven turbulence is investigated numerically in a reduced magnetohydrodynamic model. The study reveals regimes where the linear and nonlinear phases of the tearing instability are controlled by the properties of the pressure gradient. In these regimes, the interplay between the pressure and the magnetic flux determines the dynamics of the saturated state. A secondary instability can occur and strongly modify the magnetic island dynamics by triggering a poloidal rotation. It is shown that the complex nonlinear interaction between the islands and turbulence is nonlocal and involves small scales.
在一个简化的磁流体力学模型中，通过数值方法研究了嵌入在压力梯度驱动湍流中的磁撕裂岛的非线性动力学。研究揭示了线性和非线性撕裂不稳定性阶段由压力梯度特性控制的区域。在这些区域中，压力和磁通量之间的相互作用决定了饱和状态的动力学。二次不稳定性可能发生，并通过触发极向转动强烈改变磁岛动力学。结果表明，岛屿和湍流之间的复杂非线性相互作用是非局部的，并涉及小尺度。
