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In this paper we use statistical complexity and information theory metrics to study structure within solar wind time series. We explore this using entropy-complexity and information planes, where the measure for entropy is formed using…

Solar and Stellar Astrophysics · Physics 2025-10-08 Venla Koikkalainen , Emilia Kilpua , Simon Good , Adnane Osmane

We analyzed intermittency in the solar wind, as observed on the ecliptic plane, looking at magnetic field and velocity fluctuations between 0.3 and 1 AU, for both fast and slow wind and for compressive and directional fluctuations. Our…

Astrophysics · Physics 2015-06-24 R. Bruno , V. Carbone , L. Sorriso-Valvo , B. Bavassano

The Bandt-Pompe permutation entropy and the Jensen-Shannon statistical complexity are used to analyze fluctuating time series of three different plasmas: the magnetohydrodynamic (MHD) turbulence in the plasma wind tunnel of the Swarthmore…

Plasma Physics · Physics 2015-06-22 Peter J. Weck , David A. Schaffner , Michael R. Brown , Robert T. Wicks

The intermittency of density fluctuations in the solar wind at kinetic scales has been examined using high time resolution Faraday cup measurements from the Spektr-R spacecraft. It was found that the probability density functions (PDFs) of…

Space Physics · Physics 2014-06-23 C. H. K. Chen , L. Sorriso-Valvo , J. Šafránková , Z. Němeček

A well-known property of solar wind plasma turbulence is the observed anisotropy of the autocorrelations, or equivalently the spectra, of velocity and magnetic field fluctuations. Here we explore the related but apparently not well-studied…

Sheaths ahead of interplanetary coronal mass ejections (ICMEs) are turbulent heliospheric structures. Knowledge of their structure and fluctuations is important for understanding their geoeffectiveness, their role in accelerating particles,…

Space Physics · Physics 2022-08-17 E. K. J. Kilpua , S. W. Good , M. Ala-Lahti , A. Osmane , S. Pal , J. E. Soljento , L. L. Zhao , S. Bale

Parker Solar Probe (PSP) observed sub-Alfvenic solar wind intervals during encounters 8 - 14, and low-frequency magnetohydrodynamic turbulence in these regions may differ from that in super-Alfvenic wind. We apply a new mode-decomposition…

Solar wind is probably the best laboratory to study turbulence in astrophysical plasmas. In addition to the presence of magnetic field, the differences with neutral fluid isotropic turbulence are: weakness of collisional dissipation and…

Solar and Stellar Astrophysics · Physics 2015-06-16 Olga Alexandrova , Christopher H. K. Chen , Luca Sorriso-Valvo , Timothy S. Horbury , Stuart D. Bale

A statistical relationship between magnetic reconnection, current sheets and intermittent turbulence in the solar wind is reported for the first time using in-situ measurements from the Wind spacecraft at 1 AU. We identify intermittency as…

Space Physics · Physics 2015-06-19 K. T. Osman , W. H. Matthaeus , J. T. Gosling , A. Greco , S. Servidio , B. Hnat , S. C. Chapman , T. D. Phan

Preliminary results are presented which suggest that scaling and singularity characteristics of solar wind and ground based magnetic fluctuations appear to be a significant component in the solar wind - magnetosphere interaction processes.…

Space Physics · Physics 2020-01-29 Z. Vörös , D. Jankovičová , P. Kovács

Solar wind turbulence is often perceived as weakly compressible and the density fluctuations remain poorly understood both theoretically and observationally. Compressible magnetohydrodynamic simulations provide useful insights into the…

Space Physics · Physics 2023-04-12 Senbei Du , Hui Li , Zhaoming Gan , Xiangrong Fu

We study the radial evolution of intermittency of density fluctuations in the fast solar wind. The study is performed analyzing the plasma density measurements provided by Helios 2 in the inner heliosphere between $0.3$ and $0.9$ AU. The…

Solar and Stellar Astrophysics · Physics 2014-11-14 R. Bruno , D. Telloni , L. Primavera , E. Pietropaolo , R. D'Amicis , L. Sorriso-Valvo , V. Carbone , F. Malara , P. Veltri

We analyze in situ measurements of solar wind velocity obtained by the Advanced Composition Explorer (ACE) spacecraft during the solar activity cycle 23. We calculated a robust complexity measure, the permutation entropy (S) of solar wind…

Solar and Stellar Astrophysics · Physics 2011-12-23 Vinita Suyal , Awadhesh Prasad , Harinder P. Singh

We apply the finite size scaling technique to quantify the statistical properties of fluctuations in AU, AL and AE indices and in the epsilon parameter that represents energy input from the solar wind into the magnetosphere. We find that…

Space Physics · Physics 2015-06-26 B. Hnat , S. C. Chapman , G. Rowlands , N. W. Watkins , M. P. Freeman

We investigate the nature of magnetic turbulent fluctuations, around ion characteristic scales, in a fast solar wind stream, by using {\it Cluster} data. Contrarily to slow solar wind, where both Alfv\'enic ($\delta b_{\perp} \gg \delta…

Plasma Physics · Physics 2017-11-08 D. Perrone , O. Alexandrova , O. W. Roberts , S. Lion , C. Lacombe , A. Walsh , M. Maksimovic , I. Zouganelis

We present the first statistical study of the anisotropy of the magnetic field turbulence in the solar wind between 1 and 200Hz, i.e. from proton to sub-electron scales. We consider 93 10-minute intervals of Cluster/STAFF measurements. We…

Space Physics · Physics 2017-10-18 Catherine Lacombe , Olga Alexandrova , Lorenzo Matteini

The power spectrum of the evolving solar wind shows evidence of a spectral break between an inertial range of turbulent fluctuations at higher frequencies and a "$1/f$" like region at lower frequencies. In the ecliptic plane at $\sim 1$ AU,…

Solar and Stellar Astrophysics · Physics 2009-09-24 R. M. Nicol , S. C. Chapman , R. O. Dendy

The observed magnetic field on the solar surface is characterized by a very complex spatial and temporal behavior. Although feature-tracking algorithms have allowed us to deepen our understanding of this behavior, subjectivity plays an…

Turbulence is a ubiquitous process that transfers energy across many spatial and temporal scales, thereby influencing particle transport and heating. Recent progress has improved our understanding of the anisotropy of turbulence with…

Solar and Stellar Astrophysics · Physics 2025-12-08 Siqi Zhao , Huirong Yan , Terry Z. Liu , Chuanpeng Hou

We show that the scaling of structure functions of magnetic and velocity fields in a mostly highly Alfv\'{e}nic fast solar wind stream depends strongly on the joint distribution of the dimensionless measures of cross helicity and residual…

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