58 citations · 244 across the 21 of their papers we have counts for
18 papers · 1 filter
Reconstructing solar magnetic fields from historical observations X. Effect of magnetic field inclination and boundary structure on AIA 1600 Å emission
Ismo Tähtinen, Alexei A. Pevtsov, Timo Asikainen +1
The relation between the intensity of chromospheric emissions and the photospheric magnetic field strength has been examined in several studies, but the effect of the magnetic fiel…
Continuous Solar Observations from the Ground -- Assessing Duty Cycle from GONG Observations
Kiran Jain, Sushant C. Tripathy, Frank Hill +1
Continuous observations play an important role in the studies of solar variability. While such observations can be achieved from space with almost 100% duty cycle, it is difficult…
On a limitation of Zeeman polarimetry and imperfect instrumentation in representing solar magnetic fields with weaker polarization signal
Alexei A. Pevtsov, Yang Liu, Ilpo Virtanen +4
Full disk vector magnetic fields are used widely for developing better understanding of large-scale structure, morphology, and patterns of the solar magnetic field. The data are al…
The intensity and evolution of the extreme storms in January 1938
Hisashi Hayakawa, Kentaro Hattori, Alexei A. Pevtsov +7
Major solar eruptions occasionally direct interplanetary coronal mass ejections (ICMEs) to Earth and cause significant geomagnetic storms and low-latitude aurorae. While single ext…
The effect of telescope aperture, scattered light, and human vision on early measurements of sunspot and group numbers
Nina V. Karachik, Alexei A. Pevtsov, Yury A. Nagovitsyn
Early telescopic observations of sunspots were conducted with instruments of relatively small aperture. These instruments also suffered from a higher level of scattered light, and…
Evolution of Magnetic Helicity in Solar Cycle 24
Valery V. Pipin, Alexei A. Pevtsov, Yang Liu +1
We propose a novel approach to reconstruct the surface magnetic helicity density on the Sun or sun-like stars. The magnetic vector potential is determined via decomposition of vect…