Related papers: Modelling continuum intensity perturbations caused…
The last decade lead to major progress in asteroseismology and stellar physics with the advent of space missions. Thanks to the richness and precision of current oscillation spectra, sophisticated seismic probing techniques allow us now to…
Data obtained over the last three solar cycles have been analysed to reveal the relationships between the intensity of the photospheric field measured along the line of sight by the WSO group at heliolatitudes from -75 to 75 degrees and the…
Rapidly decaying slow magnetoacoustic waves are regularly observed in the solar coronal structures, offering a promising tool for a seismological diagnostics of the coronal plasma, including its thermodynamical properties. The effect of…
Helioseismic and recent asteroseismic observations reveal fine structure in the power spectrum with alternating peaks and troughs above the acoustic cut-off frequency. This structure is interpreted as the interference patterns of…
The richness and very high accuracy of the observed frequencies of solar oscillations provide tight constraints on the structure of the solar interior and hence on the assumptions underlying the calculation of solar models. This permits the…
Recent analysis of the helioseismic observations indicate that the previously observed surface torsional oscillations extend significantly downwards into the solar convection zone. In an attempt to understand these oscillations, we study…
Inertial modes have been recently detected in the Sun via helioseismology, yet their origin, evolution, and role in the dynamics of the solar plasma and magnetic field remain poorly understood. In this study, we employ global numerical…
The complex interplay between turbulence, magnetic fields, and self-gravity leads to the formation of molecular clouds out of the diffuse interstellar medium (ISM). One avenue of studying this interplay is by analyzing statistical features…
The statistical uncertainty in measuring the primordial density perturbations on a given comoving scale is dictated by the number of independent regions of that scale that are accessible to an observer. This number varies with cosmic time…
In time-distance helioseismology, information about the solar interior is encoded in measurements of travel times between pairs of points on the solar surface. Travel times are deduced from the cross-covariance of the random wave field.…
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…
Time-distance helioseismic measurements in surface- and deep-focus geometries for wave-paths that distinguish surface magnetic contributions from those due to deeper perturbations beneath a large sunspot are presented and analysed. Travel…
Changes in the sky noise spectrum are used to characterize perturbations in the ionosphere. Observations were made at the same sidereal time on multiple days using a calibrated broadband dipole and radio spectrometer covering 80 to 185 MHz.…
Plasma turbulence cascading from MHD to kinetic scales in the heliospheric plasma is believed to play a key role in coronal heating and fast solar wind acceleration, but the properties of the turbulence remain poorly constrained by…
Current helioseismology observations allow the determination of the frequencies and surface velocity amplitudes of solar acoustic modes with exceptionally high precision. In some cases, the frequency accuracy is better than one part in a…
Motivated by recent observations of distinct parallel and perpendicular signatures in magnetic helicity measurements segregated by wave period and angle between the local magnetic field and the solar wind velocity, this paper undertakes a…
The effects of acoustic wave absorption, mode conversion and transmission by a sunspot on the helioseismic inferences are widely discussed, but yet accounting for them has proved difficult for lack of a consistent framework within…
The improvements of the knowledge of the seismic structure of the inner core and the complexities thereby revealed ask for a dynamical origin. Sub-solidus convection was one of the early suggestions to explain the seismic anisotropy, but it…
Solar oscillation frequencies change with the level of magnetic activity. Localizing subsurface magnetic field concentrations in the Sun with helioseismology will help us to understand the solar dynamo. Because the magnetic fields are not…
The study of solar oscillations (helioseismology) has been a very successful method of researching the Sun. Helioseismology teaches us about the structure and mean properties of the Sun. Together with mid-resolution data, the local…