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We use data from the first six encounters of Parker Solar Probe and employ the Partial Variance of Increments ($PVI$) method to study the statistical properties of coherent structures in the inner heliosphere with the aim of exploring…

We present a measurement of the scale-dependent, three-dimensional structure of the magnetic field fluctuations in inertial range solar wind turbulence with respect to a local, physically motivated coordinate system. The Alfvenic…

空间物理 · 物理学 2012-10-09 C. H. K. Chen , A. Mallet , A. A. Schekochihin , T. S. Horbury , R. T. Wicks , S. D. Bale

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…

空间物理 · 物理学 2017-10-18 Catherine Lacombe , Olga Alexandrova , Lorenzo Matteini

The k-filtering technique and wave polarization analysis are applied to Cluster magnetic field data to study plasma turbulence at the scale of the ion gyroradius in the fast solar wind. Waves are found propagating in directions nearly…

太阳与恒星天体物理 · 物理学 2015-06-15 Owen W. Roberts , Xing Li , Bo Li

The solar wind proton temperature at 1-au has been found to be correlated with small-scale intermittent magnetic structures, i.e., regions with enhanced temperature are associated with coherent structures such as current sheets. Using…

Several studies in the near-Earth environment show that intermittent structures are important sites of energy dissipation and particle energization. Recent Parker Solar Probe (PSP) data, sampled in the near-Sun environment, have shown that…

太阳与恒星天体物理 · 物理学 2022-11-30 C. Phillips , R. Bandyopadhyay , D. J. McComas , S. D. Bale

Compressive fluctuations are a minor yet significant component of astrophysical plasma turbulence. In the solar wind, long-wavelength compressive slow-mode fluctuations lead to changes in $\beta_{\parallel \mathrm p}\equiv 8\pi n_{\mathrm…

Using high resolution Cluster satellite observations, we show that the turbulent solar wind is populated by magnetic discontinuities at different scales, going from proton down to electron scales. The structure of these layers resembles the…

太阳与恒星天体物理 · 物理学 2016-06-08 A. Greco , S. Perri , S. Servidio , E. Yordanova , P. Veltri

The rich structure that we observe in molecular clouds is due to the interplay between strong magnetic fields and supersonic (turbulent) velocity fluctuations. The velocity fluctuations interact with the magnetic field, causing it too to…

星系天体物理 · 物理学 2020-08-12 James R. Beattie , Christoph Federrath , Amit Seta

Magnetic fluctuations in the solar wind are often observed to maintain constant magnitude of the magnetic field in a manner consistent with spherically-polarized large-amplitude Alfv\'en waves. We investigate the effect of spherical…

太阳与恒星天体物理 · 物理学 2023-11-17 Corina Dunn , Trevor Bowen , Alfred Mallet , Samuel Badman , Stuart Bale

Magnetic field fluctuations in the solar wind are commonly observed to follow a power law spectrum. Near proton-kinetic scales, a spectral break occurs which is commonly interpreted as a transition to kinetic turbulence. However, this…

We use magnetic helicity to characterise solar wind fluctuations at proton-kinetic scales from Wind observations. For the first time, we separate the contributions to helicity from fluctuations propagating at angles quasi-parallel and…

We investigate possible links between the large-scale and small-scale features of solar wind fluctuations across the frequency break separating fluid and kinetic regimes. The aim is to correlate the magnetic field fluctuations polarization…

空间物理 · 物理学 2017-01-26 D. Telloni , R. Bruno

In this work, we perform a statistical study of magnetic field fluctuations in the solar wind at 1 au using permutation entropy and complexity analysis, and the investigation of the temporal variations of the Hurst exponents. Slow and fast…

太阳与恒星天体物理 · 物理学 2024-03-26 Emilia Kilpua , Simon Good , Matti Ala-Lahti , Adnane Osmane , Venla Koikkalainen

We investigate properties of the plasma fluid motion in the large amplitude low frequency fluctuations of highly Alfv\'enic fast solar wind. We show that protons locally conserve total kinetic energy when observed from an effective frame of…

空间物理 · 物理学 2015-06-23 L. Matteini , T. S. Horbury , F. Pantellini , M. Velli , S. J. Schwartz

We use fluctuating magnetic helicity to investigate the polarisation properties of Alfv\'enic fluctuations at ion-kinetic scales in the solar wind as a function of $\beta_p$, the ratio of proton thermal pressure to magnetic pressure, and…

空间物理 · 物理学 2022-04-12 L. D. Woodham , R. T. Wicks , D. Verscharen , J. M. TenBarge , G. G. Howes

Turbulence is ubiquitous in plasmas, leading to rich dynamics characterized by irregularity, irreversibility, energy fluctuations across many scales, and energy transfer across many scales. Another fundamental and generic feature of…

等离子体物理 · 物理学 2017-02-14 Vladimir Zhdankin , Stanislav Boldyrev , Dmitri A. Uzdensky

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…

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…

天体物理学 · 物理学 2015-06-24 R. Bruno , V. Carbone , L. Sorriso-Valvo , B. Bavassano

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…

空间物理 · 物理学 2014-06-23 C. H. K. Chen , L. Sorriso-Valvo , J. Šafránková , Z. Němeček