40. Fast Convective Flows Throughout the Near-Surface Shear Layer
Ring-diagram analysis reveals that the convective flow speed inside the Sun is consistent with most numerical simulations of global convection.
Category Archives: Helioseismology
36. Application of Mutual Information Methods in Time-Distance Helioseismology
What could be common between solar atmosphere and information exchange in communicating systems? Well, this is all about how information is transferred from point A to point B. This work represents a proof-of-concept application of methods of mutual information (MI) to helioseismology.
35. Fluctuations of Supergranulation Verified Through Spectral Analysis of HMI Doppler Images
The mean size of supergranulation has been found to vary over time with a period of 3-5 days. We have used full-disk Doppler images from the Helioseismic Magnetic Imager (HMI) to verify that these fluctuations are solar in origin.
28. Sunspot moats versus supergranules
Flow system in an average supergranule is compared to the moat flow around axisymmetric sunspots. Both phenomena are very similar, only the outflow in the moat is distorted due to the proper motion of the sunspot with respect to the local frame of rest and moat is a purely downflow region.
27. Anomalously Weak Convection on Large Scales in the Sun
Observed seismic upper bounds on large-scale lateral (horizontal) convective-velocity amplitudes in the solar interior at the depth r/R = 0.96 do not agree with modeling results derived at a similar depth from global convection simulations. The observations of low convective-velocity amplitudes throw into question our understanding of thermal and angular momentum transport in the Sun.
26. SDO/HMI Multi-height Dopplergrams
Multi-height Doppler velocity maps from two layers separated by 50 km are obtained from combinations of currently recorded HMI filtergrams. Using synthetic data of spectral line profiles produced in a convective environment, we test the ability to recover vertical velocity fields at different heights.
24. Solar and stellar differential rotation and dynamo, mean-field vs. global models
Numerical simulations of solar rotation and dynamo have been performed over the last decades with the aim of understanding the physics of the solar interior. Here we briefly discuss two main approaches, namely, mean-field modeling and global simulations. We also present recent results of hydrodynamic global simulations which reveal interesting aspects of stellar rotation.
23. Active Regions with Superpenumbral Whirls or Sunspots Like Pinwheels
The magnetic field of active region NOAA 11092 shows a persistent counter-clockwise twist in the solar atmosphere from the photosphere to the corona. The subsurface flows associated with this region are twisted in the opposite direction.
22. A New Solar Fluorine Abundance
New solar fluorine abundance was determined using improved molecular data. The new abundance is slightly lower than the old values previously determined in 1960s.
20. Solar Meridional Flow in the Shallow Interior during the Rising Phase of Cycle 24
Subsurface meridional flow speed shows an anti-correlation with the magnetic flux being transported poleward above the latitude of 35°. In the lower latitude, the residual meridional flow, after a long-time mean profile is subtracted, shows converging flow toward the activity belts.