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We study the evolution of turbulence in the solar wind by solving numerically the full 3D magneto-hydrodynamic (MHD) equations embedded in a radial mean wind. The corresponding equations (expanding box model or EBM) have been considered…

太阳与恒星天体物理 · 物理学 2015-06-22 Yue Dong , Andrea Verdini , Roland Grappin

We present observations of the power spectral anisotropy in wave-vector space of solar wind turbulence, and study how it evolves in interplanetary space with increasing heliocentric distance. For this purpose we use magnetic field…

太阳与恒星天体物理 · 物理学 2015-06-12 Jiansen He , Chuanyi Tu , Eckart Marsch , Sofiane Bourouaine , Zhongtian Pei

In the parts of the solar corona and solar wind that experience the fewest Coulomb collisions, the component proton, electron, and heavy ion populations are not in thermal equilibrium with one another. Observed differences in temperatures,…

太阳与恒星天体物理 · 物理学 2015-06-05 Steven R. Cranmer , Adriaan A. van Ballegooijen

We combine observations of the Coronal Multi-channel Polarimeter (CoMP) and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) to study the characteristic properties of (propagating) Alfvenic motions and…

太阳与恒星天体物理 · 物理学 2015-07-02 Jiajia Liu , Scott W. McIntosh , Ineke De Moortel , Yuming Wang

We investigate dynamo action in global compressible solar-like convective dynamos in the framework of mean-field theory. We simulate a solar-type star in a wedge-shaped spherical shell, where the interplay between convection and rotation…

太阳与恒星天体物理 · 物理学 2018-01-17 Jörn Warnecke , Matthias Rheinhardt , S. Tuomisto , Petri J. Käpylä , Maarit J. Käpylä , Axel Brandenburg

Three-dimensional numerical simulations have been used to study the scattering of a surface-gravity wave packet by vertical magnetic flux tubes, with radii from 200 km to 3 Mm, embedded in stratified polytropic atmosphere. The scattered…

太阳与恒星天体物理 · 物理学 2010-11-02 K. Daiffallah , T. Abdelatif , A. Bendib , R. Cameron , L. Gizon

The interaction of jets in High-Mass X-ray Binaries (HMXBs) with the strong winds driven by the hot companion star in the vicinity of the compact object is fundamental to understand the jet dynamics, non-thermal emission and long-term…

高能天体物理现象 · 物理学 2022-05-18 J. López-Miralles , M. Perucho , J. M. Martí , S. Migliari , V. Bosch-Ramon

One view of the solar-wind turbulence is that the observed highly anisotropic fluctuations at spatial scales near the proton inertial length $d_p$ may be considered as Kinetic Alfv\'en waves (KAWs). In the present paper, we show how…

太阳与恒星天体物理 · 物理学 2015-12-09 C. L. Vasconez , F. Pucci , F. Valentini , S. Servidio , W. H. Matthaeus , F. Malara

We extend semi-analytical computations of excitation rates for solar oscillation modes to those of other solar-like oscillating stars to compare them with recent observations. Numerical 3D simulations of surface convective zones of several…

天体物理学 · 物理学 2009-11-11 R. Samadi , D. Georgobiani , R. Trampedach R. , M. -J. Goupil , R. F. Stein , A. Nordlund

Magnetic turbulence is anisotropic as the directions of motion are constrained by the magnetic field. Such anisotropy can be observed in velocity centroids obtained from spectroscopic observations. We use magnetohydrodynamics (MHD)…

星系天体物理 · 物理学 2020-08-13 D. Hernández-Padilla , A. Esquivel , A. Lazarian , D. Pogosyan , D. Kandel , J. Cho

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…

太阳与恒星天体物理 · 物理学 2025-12-08 Siqi Zhao , Huirong Yan , Terry Z. Liu , Chuanpeng Hou

By focusing on the oscillations of the cross-sectional area and the intensity of magnetic waveguides located in the lower solar atmosphere, we aim to detect and identify magnetohydrodynamic (MHD) sausage waves. Capturing several series of…

太阳与恒星天体物理 · 物理学 2015-06-11 I. Dorotovic , R. Erdelyi , N. Freij , V. Karlovsky , I. Marquez

The expanding solar wind plasma ubiquitously exhibits anisotropic non-thermal particle velocity distributions. Typically, proton Velocity Distribution Functions (VDFs) show the presence of a core and a field-aligned beam. Novel observations…

The solar wind and the interstellar medium are permeated by large-scale magnetic fields that render magnetohydrodynamic (MHD) turbulence anisotropic. In the weak-turbulence limit in which three-wave interactions dominate, analytical and…

太阳与恒星天体物理 · 物理学 2011-09-06 C. S. Ng , A. Bhattacharjee

Over the last few years, numerical models of the behavior of solar magnetic flux tubes have gone from using methods that were essentially one-dimensional (i.e. the thin flux tube approximation), over more or less idealized two-dimensional…

天体物理学 · 物理学 2007-05-23 Bertil Dorch

Aims: Our aim is to study the presence and properties of small-scale swirls in numerical simulations of the atmospheres of cool main-sequence stars. Our particular focus is on understanding the variations in these properties for different…

太阳与恒星天体物理 · 物理学 2024-09-18 J. R. Canivete Cuissa , F. Riva , O. Steiner

M dwarf's atmosphere and wind is expected to be highly magnetized. The nonlinear propagation of Alfv\'en wave could play a key role in both heating the stellar atmosphere and driving the stellar wind. Along this Alfv\'en wave scenario, we…

太阳与恒星天体物理 · 物理学 2021-01-20 Takahito Sakaue , Kazunari Shibata

We investigate properties of plasma turbulence from magneto-hydrodynamic (MHD) to sub-ion scales by means of two-dimensional, high-resolution hybrid particle-in-cell simulations. We impose an initial ambient magnetic field, perpendicular to…

太阳与恒星天体物理 · 物理学 2015-10-14 Luca Franci , Simone Landi , Lorenzo Matteini , Andrea Verdini , Petr Hellinger

Photospheric vortex flows are thought to play a key role in the evolution of magnetic fields. Recent studies show that these swirling motions are ubiquitous in the solar surface convection and occur in a wide range of temporal and spatial…

太阳与恒星天体物理 · 物理学 2018-03-07 Iker S. Requerey , Basilio Ruiz Cobo , Milan Gošić , Luis R. Bellot Rubio

Solar flares and plasma eruptions are sudden releases of magnetic energy stored in the plasma atmosphere. To understand the physical mechanisms governing their occurrences, three-dimensional magnetic fields from the photosphere up to the…

太阳与恒星天体物理 · 物理学 2021-03-24 Takafumi Kaneko , Sung-Hong Park , Kanya Kusano