Features of spatial distribution of oscillations in faculae regions

We found that oscillations of LOS velocity in H-alpha are different for various parts of faculae regions. Power spectra show that the contribution of low-frequency modes (1.2 - 2 mHz) increase at the network boundaries. Three and five- minute periods dominate inside cells. The spectra of photosphere and chromosphere LOS velocity oscillations differ for most faculae. On the other hand, we detected several cases where propagating oscillations in faculae were manifest with a five-minute period. Their initiation point on spatial-temporal diagrams coincided with the local maximum of the longitudinal magnetic field.Comment: 6 pages, 4 figure

Development modulationless measuring magnetic fields and differential velocities at Sayan observatory

In this paper we consider the possibility of modulationless measuring the magnetic-field strength and the differential line-of-sight velocity, based on using a diffraction spectrograph and multichannel CCD photodetectors. The optical system for implementing the method is described. Results of trial observations are presented. When measuring the differential velocity, the spectrograph’s inherent noise is reduced by factors of 35–40. It becomes possible to measure the longitudinal magnetic-field strength in a single exposure even if the CCD array is used. This can be particularly attractive when reducing the influence of atmospheric instabilities on the result of magnetic-field measurement using CCD arrays

Flows and oscillations in sunspot penumbra

In observations of penumbra oscillations there is the challenging problem of separating the oscillations associated with Evershed flows from those of a different nature. The authors used the differential method which is best suited to this problem as it can be used to filter out the wave motions in the direction and wavelength already at the stage of observation. Our findings indicate that, in addition to the 10–12 min periods, periods near 30–35 minutes are present in the velocity variations of Evershed flows. Furthermore, the possible candidates for this role are the 8 min oscillations, which we have also observed at two height levels of sunspot penumbra

Comparing the main oscillation characteristics in the solar chromosphere and magnetosphere based on studies made in ISTP SB RAS

The aim of this paper is to structure and extend the knowledge of solar chromospheric sources of oscillations in the solar wind and their relationships with pulsations registered in the magnetosphere. We compare the oscillation spectra that we observe using instruments of the Institute of Solar-Terrestrial Physics in different chromospheric structures with those observed in the solar wind and magnetosphere. We explore the possibility that the observed periodic variations of the chromospheric line widths can be interpreted as torsional Alfvén wave manifestation—this mode can propagate long distances without dissipating in the interplanetary space; it can penetrate into Earth’s magnetosphere directly or due to processes occurring at the plasmapause. We emphasize the similarities in the oscillation characteristics observed in different media, the similarities in the parameters of the media themselves and the processes developing in them. We believe that similar approaches can be applied to studying these media

Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review