MULTIFRACTAL STRUCTURES DETECTED BY VOYAGER 1 AT THE HELIOSPHERIC BOUNDARIES
MULTIFRACTAL STRUCTURES DETECTED BY VOYAGER 1 AT THE HELIOSPHERIC BOUNDARIES
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航行者 1 号在日球层边界检测到的多重分形结构
DOI：
10.1088/2041-8205/793/2/l30
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
L. Burlaga
中科院分区：
文献类型：
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作者：
W. Macek;A. Wawrzaszek;L. Burlaga
为了更好地理解湍流系统的动力学，我们提出了一个基于具有两个重新标度参数和一个权重参数的广义康托集的唯象模型。在这封信中，使用最近的旅行者1号磁场数据，我们进一步扩展我们的双尺度多重分形分析在日鞘超出日光层终止激波，甚至现在接近太阳风顶，当进入星际介质在人类历史上的第一次。我们确定了在终端激波和日球顶之间的磁化日球等离子体的标度惯性区。我们还表明，多重分形的程度随着日心距离的减小，仍然是调制的太阳周期的相位在整个日光层，包括日鞘。此外，我们观察到的变化的缩放朝着非间歇性（nonmultifractal）的行为在附近的星际介质，就在太阳风层顶。我们认为，这种多重分形行为的损失可能是旅行者2号在不久的将来预期穿越日球层顶的一个标志。结果表明，我们的多重分形唯象模型显示了太阳系等离子体中间歇性湍流的某些性质，并希望它能对湍流的普遍特征有所启发。
To better understand the dynamics of turbulent systems, we have proposed a phenomenological model based on a generalized Cantor set with two rescaling and one weight parameters. In this Letter, using recent Voyager 1 magnetic field data, we extend our two-scale multifractal analysis further in the heliosheath beyond the heliospheric termination shock, and even now near the heliopause, when entering the interstellar medium for the first time in human history. We have identified the scaling inertial region for magnetized heliospheric plasma between the termination shock and the heliopause. We also show that the degree of multifractality decreases with the heliocentric distance and is still modulated by the phases of the solar cycle in the entire heliosphere including the heliosheath. Moreover, we observe the change of scaling toward a nonintermittent (nonmultifractal) behavior in the nearby interstellar medium, just beyond the heliopause. We argue that this loss of multifractal behavior could be a signature of the expected crossing of the heliopause by Voyager 2 in the near future. The results obtained demonstrate that our phenomenological multifractal model exhibits some properties of intermittent turbulence in the solar system plasmas, and we hope that it could shed light on universal characteristics of turbulence.