Related papers: Velocity Fields in the Solar Photosphere
We investigate the two-dimensional velocity field of the fast and complex large-scale coronal wave observed on September 6, 2011. We use both a classical perturbation profile approach and the newly developed multi-sector method of the…
Measuring the magnetic helicity distribution in the solar corona can help in understanding the trigger of solar eruptive events because magnetic helicity is believed to play a key role in solar activity due to its conservation property. A…
Magnetic helicity is a key geometrical parameter to describe the structure and evolution of solar coronal magnetic fields. The accumulation of magnetic helicity is correlated with the non-potential magnetic field energy, which is released…
Determining accurate velocity measurements from observations of the Sun is of vital importance to solar physicists who are studying the wave dynamics in the solar atmosphere. Weak chromospheric absorption lines, due to dynamic events in the…
We compare photospheric line-of-sight magnetograms from the Synoptic Long-term Investigations of the Sun (SOLIS) vector spectromagnetograph (VSM) instrument with observations from the 150-foot Solar Tower at Mt. Wilson (MWO), Helioseismic…
High cadence, multi-wavelength observations and simulations are employed for the analysis of solar photospheric magnetic bright points (MBPs) in the quiet Sun. The observations were obtained with the Rapid Oscillations in the Solar…
In this review, our present day understanding of the Sun's global photospheric and coronal magnetic fields is discussed from both observational and theoretical viewpoints. Firstly, the large-scale properties of photospheric magnetic fields…
Surface observations indicate that the speed of the solar meridional circulation in the photosphere varies in anti-phase with the solar cycle. The current explanation for the source of this variation is that inflows into active regions…
The solar wind is connected to the Sun's atmosphere by flux tubes that are rooted in an ever-changing pattern of positive and negative magnetic polarities on the surface. Observations indicate that the magnetic field is filamentary and…
Over the past 15 years, our knowledge of the interior of the Sun has tremendously progressed by the use of helioseismic measurements. However, to go further in our understanding of the solar core, we need to measure gravity (g) modes.…
Solar torsional oscillations are migrating bands of slower- and faster-than-average rotation, which are strongly related to the Sun's magnetic cycle. We perform a long-term study (16 yr) of hemispherical asymmetry in solar torsional…
We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies are obtained by tracking the temporal…
We developed a method to automatically detect and trace solar filaments in H\alpha\ full-disk images. The program is able not only to recognize filaments and determine their properties, such as the position, the area, the spine, and other…
The Sun is replete with magnetic fields, with sunspots, pores and plage regions being their most prominent representatives on the solar surface. But even far away from these active regions, magnetic fields are ubiquitous. To a large extent,…
The present study addresses the following questions: How representative of the actual velocities in the solar atmosphere are the Doppler shifts of spectral lines? How reliable is the velocity signal derived from narrowband filtergrams? How…
We tested whether simultaneous spectropolarimetric imaging in two magnetically sensitive optical spectral lines, which probe two different layers of the solar atmosphere (the photosphere and the temperature minimum), can help constrain the…
Using a numerical simulation of compressible convection with radiative transfer mimicking the solar photosphere, we compare the velocity field derived from granule motions to the actual velocity field of the plasma. We thus test the idea…
The solar interior is filled with turbulent thermal convection, which plays a key role in the energy and momentum transport and the generation of the magnetic field. The turbulent flows in the solar interior cannot be optically detected due…
In a previous paper, I described a new way of determining the high-latitude solar rotation rate statistically from space-time maps of polar faculae observed in the 6767 \r{A} continuum by the Michelson Doppler Interferometer (MDI) on the…
We have measured zonal and meridional components of subsurface flows up to a depth of 30 Mm below the solar surface by applying the technique of ring diagram on Dopplergrams which are constructed from the spherical harmonic (SH)…