相关论文: The Alfv\'enic nature of chromospheric swirls
Magnetic fields are believed to be generated in the cores of massive main sequence stars, and these may survive on to later stages of evolution. Observations of depressed dipole modes in red giant stars have been touted as evidence for…
Using spatio-temporal spectra we show direct evidence of excitation of magnetosonic and Alfv\'en waves in three-dimensional compressible magnetohydrodynamic turbulence at small Mach numbers. For the plasma pressure dominated regime, or high…
The degree of linear polarization has recently been found to show wide random variations over the solar disk. These variations are presumably at least partly due to fluctuations in the flux density of turbulent photospheric magnetic fields…
We perform three dimensional (3D) ideal magnetohydrodynamic (MHD) simulations to study the parametric decay instability of Alfven waves in turbulent plasmas and explore its possible applications in the solar wind. We find that, over a broad…
The problem of solar chromospheric heating remains a challenging one with wider implications for stellar physics. Several studies in the recent past have shown that small-scale inclined magnetic field elements channel copious amount of…
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…
It is shown that a three-dimensional (3D) modified-kinetic Alfv\'en waves (m-KAWs) can propagate in the form of Alfv\'enic tornadoes characterized by plasma density whirls or magnetic flux ropes carrying orbital angular momentum (OAM). By…
In the framework of compressional magnetohydrodynamics (MHD), we numerically studied the commonly accepted presumption that the Alfv\'enic turbulence is generated by the collisions between counter-propagating Alfv\'en waves (AWs). In the…
Fluctuations in the Sun's photospheric magnetic field are the primary source of the turbulence that can heat and accelerate the solar atmosphere, and thus play an important role in the production and evolution of the solar wind that…
Composed of shocked solar wind, the Earth's magnetosheath serves as a natural laboratory to study the transition of turbulence from low Alfv{\'e}n Mach number, $M_\mathrm{A}$, to high $M_\mathrm{A}$. The simultaneous observations of…
We investigate the magnetic characteristics of a persistent coronal hole (CH) extracted from EUV imagery using HMI filtergrams over the timerange February 2012-October 2012. The magnetic field, its distribution as well as the magnetic fine…
New high-resolution observations reveal that small-scale magnetic flux concentrations have a delicate substructure on a spatial scale of 0.1''. Its basic structure can be interpreted in terms of a magnetic flux sheet or tube that vertically…
We study the spatio-temporal behavior of the Els\"asser variables describing magnetic and velocity field fluctuations, using direct numerical simulations of three-dimensional magnetohydrodynamic turbulence. We consider cases with relatively…
In the near future, Parker Solar Probe will put theories about the dynamics and nature of the transition between the solar corona and the solar wind to stringent tests. The most popular mechanism aimed to explain the dynamics of the nascent…
We present the first observations of chromospheric swirls using the Hydrogen-alpha Rapid Dynamics camera and Rapid Oscillations in the Solar Atmosphere imaging instruments at the Dunn Solar Telescope. These vortices contribute to heating…
We investigate compressive turbulence at sub-ion scales with measurements from the Magnetospheric MultiScale Mission. The tetrahedral configuration and high time resolution density data obtained by calibrating spacecraft potential allow an…
A three-dimensional MHD model for the propagation and dissipation of Alfven waves in a coronal loop is developed. The model includes the lower atmospheres at the two ends of the loop. The waves originate on small spatial scales (less than…
The density fluctuation spectrum in the solar wind reveals a Kolmogorov-like scaling with a spectral slope of -5/3 in wavenumber space. The energy transfer process in the magnetized solar wind, characterized typically by MHD turbulence,…
Combined action of helical motions of plasma (the $\alpha$ effect) and non-uniform (differential) rotation is a key dynamo mechanism of solar and galactic large-scale magnetic fields. Dynamics of magnetic helicity of small-scale fields is a…
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…