A partial decrease of the convective energy by the magnetic field of a sunspot causes the temperature of the magnetized plasma to decrease and this leads to a magneto-hydrostatic equilibrium. Thus, we expect a strong relation between magnetic field strength of a sunspot and its temperature/brightness. Here, we investigate this relation in the umbra of the large sunspot in NOAA10930 using spectr...

It is proposed that sunspots (and other flux emergence phenomena) originate due to the presence of fluctuating magnetic fields in addition to the regular, mean field in the convection zone. The mean field predicted by dynamo theories is too weak by itself to emerge at the surface of the Sun. However, the same dynamoprocesses that produce themeanfield also produce fluctuating fields. It is sugge...

It is generally believed that sunspots are the emergent part of magnetic flux tubes in the solar interior. These tubes are created at the base of the convection zone and rise to the surface due to their magnetic buoyancy. The motion of plasma in the convection zone being highly turbulent, the surface manifestation of sunspots may retain the signature of this turbulence, including its intermitte...

Bright EUV sunspot plumes have been observed in five out of nine sunspot regions with the Coronal Diagnostic Spectrometer – CDS on SOHO. In the other four regions the brightest line emissions may appear inside the sunspot but are mainly concentrated in small regions outside the sunspot areas. These results are in contrast to those obtained during the Solar Maximum Mission, but are compatible wi...

This article is a continuation of the works1-4 author, devoted to elucidating physical nature dark sunspots. It has been proven that scientific paradigm cold sunspots prevailing in solar physics erroneous, since it contradicts second law thermodynamics. photosphere can only be hotter than photosphere, and their visual darkness non-thermal nature. Sunspots are hottest areas Sun's surface, temper...

The sun is the unlimited energy source for life on the earth. However, besides as the energy source, the sun also gives disruptions to the universe around the earth and also to the life on the earth. Sources of the disruptions from the sun are flares and Coronal Mass Ejection/CME. Both of those disruptions in general come from group of sunspots. With the growing of dependency of human life with...

1. INTRODUCTION " If the Sun had no magnetic field, it would be as uninteresting as most astronomers think it is. " This statement is attributed to R. B. Leighton (Moore and Rabin, 1985). Personally I think the Sun is of enormous interest in all respects, magnetic and non-magnetic; nonetheless, the grand challenges I have selected for this article do indeed pertain to the Sun's magnetic field. ...

Using Yohkoh SXT and Nobeyama 17 GHz data, we have studied the soft X{ray and microwave emission above several stable, large sunspots near central meridian passage. Our study connrms the well known fact that soft X{ray emission is depressed above sunspots. It also shows that the distribution of their soft X{ray intensity is not uniform; usually the darkest pixels are associated with the umbra o...

Recent observations of helioseismic holography revealed that magnetic fields that are inclined relative to the line-of-sight direction could cause systematic variations in measured acoustic phase shifts (hereafter, “inclined magnetic field effect”), and that the presence of surface magnetic field may shift the phases and impair the coherence of acoustic waves (known as “showerglass effect”), th...

Based on Singular Spectral Analysis (SSA) analysis of global earth surface temperature and solar activity (sunspots), Le Mouël et al. (2020, https://doi.org/10.1029/2019EA000671) suggest that the variability in Earth observed since 1850 is natural controlled by Sun. We cannot agree with their conclusions for several reasons: lack compelling results from Fourier spectra SSA estimates which are p...