Chaos in magnetic flux ropes
Chaos in magnetic flux ropes
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DOI：
10.1088/0741-3335/56/6/064002
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发表时间：
2014-06-01
影响因子：
2.2
通讯作者：
Vincena, Stephen
中科院分区：
文献类型：
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作者：
Gekelman, Walter;Van Compernolle, Bart;Vincena, Stephen
在均匀磁等离子体中，磁通绳可以绕自身扭曲、相互缠绕和绕中心轴旋转。他们是扭结不稳定和粉碎到彼此，因为他们移动。每次碰撞都会导致磁力线重联和准分界线层的产生。三维磁场线计算有条件地平均数据使用相关技术。有条件的平均是可能的，只有一些旋转周期的磁力线运动变得混乱。置换熵可以从磁场数据的时间序列中计算出来（这也可以用流来完成），并用于计算数据在詹森-香农复杂度图上的位置。该地图上的数据位置表明磁场是否是随机的，或者落入最小或最大复杂性的区域。复杂性是空间和时间的函数。计算的李雅普诺夫和赫斯特指数和复杂性和置换熵的流量和字段组件显示在整个体积。
Magnetic flux ropes immersed in a uniform magnetoplasma are observed to twist about themselves, writhe about each other and rotate about a central axis. They are kink unstable and smash into one another as they move. Each collision results in magnetic field line reconnection and the generation of a quasi-separatrix layer. Three-dimensional magnetic field lines are computed by conditionally averaging the data using correlation techniques. Conditional averaging is possible for only a number of rotation cycles as the field line motion becomes chaotic. The permutation entropy can be calculated from the time series of the magnetic field data (this is also done with flows) and is used to calculate the positions of the data on a Jensen-Shannon complexity map. The location of data on this map indicates if the magnetic fields are stochastic, or fall into regions of minimal or maximal complexity. The complexity is a function of space and time. The Lyapunov and Hurst exponents are calculated and the complexity and permutation entropy of the flows and field components are shown throughout the volume.