Related papers: Asymmetric Distribution of the Solar Photospheric …
We report observations of a steady 20 year decline of solar photospheric fields at latitudes $\geq$45${^{o}}$ starting from $\sim$1995. This prolonged and continuing decline, combined with the fact that Cycle 24 is already past its peak,…
Thirty-four years of WSO (Wilcox Solar Observatory) and thirteen years of SOHO/MDI (Michelson Doppler Imager on the Solar and Heliospheric Observatory) magnetograms have been studied to measure the east-west inclination angle, indicating…
Solar activity seems quite understandable when considered on the scales comparable with a solar cycle, i.e. about 11 years, and on a short time scale of about a year. A solar cycle looks basically (anti)symmetric with respect to the solar…
In the present work, we investigate how the large-scale magnetic field of the Sun, in its three vector components, has evolved during most of cycle 24, from 2010 Jan to 2018 Apr. To filter out the small-scale field of the Sun, present in…
A new model has been proposed for magnetic field determination at different distances from the Sun during different solar cycle phases. The model depends on the observed large-scale non-polar photospheric magnetic fields and that measured…
In this article, we report an evidence of very high and statistically significant relationship between hemispheric asymmetry in solar coronal rotation rate and solar activity. Our approach is based on cross correlation of hemispheric…
Using time-distance helioseismic measurements of meridional flow in the near-surface shear layer over a period of 14 years, starting from May 2010, we probe the depth structure and evolution of its cross-equatorial part. We confirm that the…
The polar magnetic fields of the Sun play an important role in governing solar activity and powering fast solar wind. However, because our view of the Sun is limited in the ecliptic plane, the polar regions remain largely uncharted. Using…
We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated…
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 Sun's surface field, especially the polar field, sets the boundary condition for the coronal and heliospheric magnetic fields, but also provides us insight into the dynamo process. The evolution of the polar fields results from the…
Detailed study of the solar magnetic field is crucial to understand its generation, transport and reversals. The timing of the reversals may have implications on space weather and thus identification of the temporal behavior of the critical…
The Sun's polar magnetic fields change their polarity near the maximum of sunspot activity. We analyzed the polarity reversal epochs in Solar Cycles 21 to 24. There was a triple reversal in the N-hemisphere in Solar Cycle 24 and single…
Although systematic measurements of the solar polar magnetic field exist only from mid 1970s, other proxies can be used to infer the polar field at earlier times. The observational data indicate a strong correlation between the polar field…
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…
It is well known that the dominant frequency of oscillations in the solar photosphere is $\approx$3 mHz, which is the result of global resonant modes pertaining to the whole stellar structure. However, analyses of the horizontal motions of…
We have been monitoring yearly variation in the Sun's polar magnetic fields with the Solar Optical Telescope aboard {\it Hinode} to record their evolution and expected reversal near the solar maximum. All magnetic patches in the magnetic…
We regard the Sun-as-a-star magnetic field (i.e. the mean field) as a filter for the spherical harmonic components of the photospheric field, and calculate the transmission coefficients of this filter. The coefficients for each harmonic,…
A study on North South (NS) asymmetry of different solar activity features (DSAF) such as solar proton events, solar active prominences, H alpha flare index, soft X ray flares, monthly mean sunspot area and monthly mean sunspot number were…
The morphological asymmetry of leading and following sunspots is a well-known characteristic of the solar surface. In the context of large-scale evolution of the surface magnetic field, the asymmetry has been assumed to have only a…