相关论文: Probing the Sun's Near Surface Shear Layer using H…
Context: Solar sectoral Rossby waves have only recently been unambiguously identified in Helioseimsic and Magnetic Imager (HMI) and Michelson Doppler Imager (MDI) maps of flows near the solar surface. So far this has not been done with the…
Adverse space weather effects can often be traced to solar flares, prediction of which has drawn significant research interests. The Helioseismic and Magnetic Imager (HMI) produces full-disk vector magnetograms with continuous high cadence,…
We present analysis of the evolution of subsurface flows in and around active regions with peculiar magnetic configurations and compare their characteristics with the normal active regions. We also study the zonal and meridional components…
The continuous high spatial-resolution Doppler observation of the Sun by Solar Dynamics Observatory / Helioseismic and Magnetic Imager allows us to compute helioseismic k-omega power-spectrum diagram using only oscillations inside a…
Solar supergranulation presents us with many mysteries. For example, previous studies in spectral space found that supergranulation has wave-like properties. Here we study, in real space, the wave-like evolution of the average supergranule…
Observations show that propagating magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. The technique of MHD seismology uses the wave observations combined with MHD wave theory to indirectly infer physical parameters of…
The slow solar wind is generally believed to result from the interaction of open and closed coronal magnetic flux at streamers and pseudostreamers. We use 3-dimensional magnetohydrodynamic simulations to determine the detailed structure and…
We have analyzed available full-disc data from the Michelson Doppler Imager (MDI) on board SoHO using the "ring diagram" technique to determine the behavior of solar meridional flows over solar cycle 23 in the outer 2% of the solar radius.…
We present a series of radiative MHD simulations addressing the origin and distribution of mixed polarity magnetic field in the solar photosphere. To this end we consider numerical simulations that cover the uppermost 2-6 Mm of the solar…
Solar flares, especially the M- and X-class flares, are often associated with coronal mass ejections (CMEs). They are the most important sources of space weather effects, that can severely impact the near-Earth environment. Thus it is…
Comprehending the manner in which magnetic fields affect propagating waves is a first step toward constructing accurate helioseismic models of active region sub-surface structure and dynamics. Here, we present a numerical method to compute…
The internal dynamics of the Sun generate magnetic and plasma structures in the photosphere and overlying atmosphere across a wide range of spatial scales. Identifying the critical spatial scale is essential for interpreting physical…
It is well-known that the global acoustic oscillations of the Sun's atmosphere can excite resonance modes within large-scale magnetic concentrations. These structures are conduits of energy between the different layers of the solar…
We use the magnetic butterfly diagram to determine the speed of the magnetic flux transport on the solar surface towards the poles. The manifestation of the flux transport is clearly visible as elongated structures extended from the sunspot…
An investigation on correlations between photospheric current helicity and subsur- face kinetic helicity is carried out by analyzing vector magnetograms and subsurface velocities for two rapidly developing active regions. The vector…
Using helioseismic holography strong evidence is presented that the phase (or equivalent travel-time) of helioseismic signatures in Dopplergrams within sunspots depend upon the line-of-sight angle in the plane containing the magnetic field…
Direct seismic imaging of sub-surface flow, sound-speed and magnetic field is crucial for predicting flux tube emergence on the solar surface, an important ingredient for space weather. The sensitivity of helioseismic mode-amplitude…
We investigate the oscillatory properties of the quiet solar chromosphere in relation to the underlying photosphere, with particular regard to the effects of the magnetic topology. We perform a Fourier analysis on a sequence of…
We review (i) observations and numerical simulations of vortical flows in the solar atmosphere and (ii) measurements of the horizontal magnetic field in quiet Sun regions. First, we discuss various manifestations of vortical flows and…
Hydrodynamic simulations of granular convection predict the existence of supersonic flows covering ~3-4% of the solar surface at any time, but these flows have not been detected unambigously as yet. Using data from the spectropolarimeter…