Related papers: What does helioseismology tell us about solar cycl…
Helioseismology, the study of global solar oscillations, has proved to be an extremely powerful tool for the investigation of the internal structure and dynamics of the Sun. Studies of time changes in frequency observations of solar…
The Sun's internal structure and dynamics can be studied with helioseismology, which uses the Sun's natural acoustic oscillations to build up a profile of the solar interior. We discuss how solar acoustic oscillations are affected by the…
Helioseismology has produced unprecedented measurements of the Sun's internal structure and dynamics over the past 25 years. Much of this work has been based on global helioseismology. Now local helioseismology too is showing its great…
The structure of the surface layers of the Sun is changed by magnetic activity which, in turn, changes the eigenfrequencies of the acoustic modes. These frequency shifts have been observed both in low- and high-degree data, and are found to…
During the last 50 years we have been witness of an extraordinary revolution in the knowledge and understanding of our star thanks to the development of Helioseismology, the study of solar oscillations. Similar to what happens on the Earth…
Helioseismology has provided very precise information about the solar internal sound speed and density throughout most of the solar interior. The results are generally quite close to the properties of standard solar models. Since the solar…
Despite recent major advances, the opacity remains a source of substantial uncertainty in the calculation of solar models, and hence of solar oscillation frequencies. Hence it is of substantial interest to investigate the sensitivity of…
Solar oscillations consist of a rich spectrum of internal acoustic waves and surface gravity waves, stochastically excited by turbulent convection. They have been monitored almost continuously over the last ten years with high-precision…
Solar oblateness has been the subject of several studies dating back to the nineteenth century. Despite diffculties, both theoretical and observational, tangible results have been achieved. However, variability of the solar oblateness with…
The questions whether the Sun shrinks with the solar activity and what causes this have been a subject of debate. Helioseismology provides means to measure with high precision the radial displacement of subsurface layers, co-called "seismic…
The frequencies of solar oscillations are known to change with solar activity. We use Principal Component Analysis to examine these changes with high precision. In addition to the well-documented changes in solar normal mode oscillations…
Oscillations detected on the solar surface provide a unique possibility for investigations of the interior properties of a star. Through major observational efforts, including extensive observations from space, as well as development of…
The overall framework for the study of solar convection and oscillations is the spherically symmetric component of solar structure. I discuss those properties of the solar interior which depend on convection and other possible…
Helioseismology studies the structure and dynamics of the Sun's interior by observing oscillations on the surface. These studies provide information about the physical processes that control the evolution and magnetic activity of the Sun.…
The theory of stellar structure can be used to identify the most plausible mechanisms for the irradiance variations associated with the solar cycle. Changes in surface emissivity, i.e. the reduced cooling in spots and enhanced emission by…
We investigate spatio-temporal evolution of high-degree acoustic mode frequencies of the Sun and the surface magnetic activity, over the course of multiple solar cycles, to improve our understanding of the connection between the solar…
We show that the mean phase of waves propagating all the way from the far side of the Sun to the front side, as measured by seismic holography, varies with time. The change is highly anticorrelated with solar cycle activity and is…
We investigate the variation of high-degree mode frequencies as a local response to the active regions in two different phases of the solar activity cycle. We find that the correlation between frequency shifts and the surface magnetic…
We use helioseismic data obtained over two solar cycles to determine whether there are changes in the near-surface shear layer (NSSL). We examine this by determining the radial gradient of the solar rotation rate. The radial gradient itself…
Using data from the Global Oscillations Network Group (GONG) that covers the period from 1995 to 1998 we study the change in frequencies of solar oscillations with solar activity. From these frequencies we attempt to determine any possible…