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相关论文: Study of the 1/f spectrum using virtual spacecraft…

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We present a mechanism for the formation of the low frequency 1/f magnetic spectrum based on numerical solutions of a shell reduced-MHD model of the turbulent dynamics inside the sub-Alfv\'enic solar wind. We assign reasonably realistic…

太阳与恒星天体物理 · 物理学 2015-06-04 A. Verdini , R. Grappin , R. Pinto , M. Velli

Strong Alfv\'enic turbulence develops eddy-like motions perpendicular to the local direction of magnetic fields. This local alignment induces velocity gradients perpendicular to the local direction of the magnetic field. We use this fact to…

星系天体物理 · 物理学 2017-01-25 Diego F. González-Casanova , A. Lazarian

With the ultimate aim of using the fundamental or $f$-mode to study helioseismic aspects of turbulence-generated magnetic flux concentrations, we use randomly forced hydromagnetic simulations of a piecewise isothermal layer in two…

太阳与恒星天体物理 · 物理学 2015-06-19 Nishant K. Singh , Axel Brandenburg , S. M. Chitre , Matthias Rheinhardt

In the present paper, we investigate the power-law behaviour of the magnetic field spectra in the Earths magnetosheath region using Cluster spacecraft data under solar minimum condition. The power spectral density of the magnetic field data…

空间物理 · 物理学 2019-08-08 N. K. Dwivedi , S. Kumar , P. Kovacs , E. Yordanova , M. Echim , R. P. Sharma , M. L. Khodachenko , Y. Sasunov

We investigate the transition of the solar wind turbulent cascade from MHD to sub-ion range by means of a detail comparison between in situ observations and hybrid numerical simulations. In particular we focus on the properties of the…

空间物理 · 物理学 2020-09-01 L. Matteini , L. Franci , O. Alexandrova , C. Lacombe , S. Landi , P. Hellinger , E. Papini , A. Verdini

Probing magnetic fields in astrophysical environments is both important and challenging. The Gradient Technique (GT) is a new tool for tracing magnetic fields, rooted in the properties of magnetohydrodynamic (MHD) turbulence and turbulent…

星系天体物理 · 物理学 2024-06-18 Yue Hu , Alex Lazarian

Anisotropy of MHD turbulence has been studied extensively for many years, most prominently by measurements in the solar wind and high resolution simulations. The spectrum parallel to the local magnetic field was observed to be steeper than…

太阳与恒星天体物理 · 物理学 2015-06-22 Andrey Beresnyak

In this paper we investigate spectral and phase coherence properties of magnetic fluctuations in the vicinity of the spectral transition from large, magnetohydrodynamic (MHD) to sub-ion scales using in-situ measurements of the Wind…

太阳与恒星天体物理 · 物理学 2016-06-15 Sonny Lion , Olga Alexandrova , Arnaud Zaslavsky

The nonlinear dynamics of a bundle of magnetic flux ropes driven by stationary fluid motions at their endpoints is studied, by performing numerical simulations of the magnetohydrodynamic (MHD) equations. The development of MHD turbulence is…

等离子体物理 · 物理学 2009-11-10 Pablo Dmitruk , Daniel O. Gomez , William H. Matthaeus

The question is addressed to what extent incompressible magnetohydrodynamics (MHD) can describe random magnetic and velocity fluctuations measured in the solar wind. It is demonstrated that distributions of spectral indices for the…

星系天体物理 · 物理学 2015-05-28 Stanislav Boldyrev , Jean Carlos Perez , Joseph E. Borovsky , John J. Podesta

We present a quantitative estimate of the anisotropic power and scaling of magnetic field fluctuations in inertial range magnetohydrodynamic turbulence, using a novel wavelet technique applied to spacecraft measurements in the solar wind.…

等离子体物理 · 物理学 2009-11-13 T. S. Horbury , M. A. Forman , S. Oughton

(Abridged) Wavelet analysis can be used to measure the power spectrum of solar wind fluctuations along a line in any direction with respect to the local mean magnetic field. This technique is applied to study solar wind turbulence in…

地球与行星天体物理 · 物理学 2011-02-11 J. J. Podesta

We investigate the anisotropy of Alfv\'enic turbulence in the inertial range of slow solar wind and in both driven and decaying reduced magnetohydrodynamic simulations. A direct comparison is made by measuring the anisotropic second-order…

空间物理 · 物理学 2012-08-20 C. H. K. Chen , A. Mallet , T. A. Yousef , A. A. Schekochihin , T. S. Horbury

The power spectrum of magnetic-field fluctuations in the fast solar wind ($V_{\rm SW}> 500 \mbox{ km} \mbox{ s}^{-1}$) at magnetohydrodynamic (MHD) scales is characterized by two different power laws on either side of a break frequency…

It is well-known that magnetohydrodynamic (MHD) turbulence is ubiquitous in astrophysical environments. The correct understanding of the fundamental properties of MHD turbulence is a prerequisite for revealing many key astrophysical…

高能天体物理现象 · 物理学 2022-03-18 Jianfu Zhang , Ruyue Wang

We investigate the 1/f noise of the Five-hundred-meter Aperture Spherical Telescope (FAST) receiver system using drift-scan data from an intensity mapping pilot survey. All the 19 beams have 1/f fluctuations with similar structures. Both…

天体物理仪器与方法 · 物理学 2021-10-13 Wenkai Hu , Yichao Li , Yougang Wang , Fengquan Wu , Bo Zhang , Ming Zhu , Shifan Zuo , Guilaine Lagache , Yinzhe Ma , Mario G. Santos , Xuelei Chen

In interstellar medium studies, separating ordered and random velocity or magnetic fields is essential for interpreting turbulence in both simulations and observations. We investigate how the choice of averaging scale affects the…

星系天体物理 · 物理学 2026-04-01 A. Konstantinou , E. Ntormousi , K. Tassis

We study compressible MHD turbulence, which holds key to many astrophysical processes, including star formation and cosmic ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid we use wavelet…

星系天体物理 · 物理学 2015-05-18 Grzegorz Kowal , Alex Lazarian

Previous studies have established that a weak-to-strong transition occurs in Alfvenic magnetohydrodynamic (MHD) turbulence as energy cascades from large to small scales. However, the spatiotemporal (frequency-wavenumber) properties of…

等离子体物理 · 物理学 2026-03-10 Siqi Zhao , Huirong Yan , Terry Z. Liu , Chuanpeng Hou , Ka Ho Yuen

Direct measurements of three-dimensional magnetic fields in the interstellar medium (ISM) are not achievable. However, the anisotropic nature of magnetohydrodynamic (MHD) turbulence provides a novel way of tracing the magnetic fields.…

星系天体物理 · 物理学 2021-07-14 Yue Hu , A. Lazarian , Siyao Xu