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New Homogeneous Dataset of Solar EUV synoptic maps from SOHO/EIT and SDO/AIA
Amr Hamada, Timo Asikainen, Kalevi Mursula
Synoptic maps of solar EUV intensities have been constructed for many decades in order to display the distribution of the different EUV emissions across the solar surface, with eac…
A new signal of the solar magnetic cycle: Opposite shifts of weak magnetic field distributions in the two hemispheres
Tibebu Getachew, Ilpo Virtanen, Kalevi Mursula
We study the asymmetric distribution of weak photospheric magnetic field values in the two hemispheres separately using synoptic maps from SDO/HMI, SOLIS/VSM and WSO during solar c…
Reconstructing solar magnetic fields from historical observations V. Sunspot magnetic field measurements at Mount Wilson Observatory
Alexei A. Pevtsov, Kseniya A. Tlatova, Alexander A. Pevtsov +7
Context. Systematic observations of magnetic field strength and polarity in sunspots began at Mount Wilson Observatory (MWO), USA in early 1917. Except for a few brief interruption…
Asymmetric distribution of weak photospheric magnetic field values
Tibebu Getachew, Ilpo Virtanen, Kalevi Mursula
We use the synoptic maps of the photospheric magnetic field observed at Wilcox Solar Observatory, Mount Wilson Observatory, Kitt Peak, SOHO/MDI, SOLIS/VSM, and SDO/HMI to study the…
Structure and evolution of the photospheric magnetic field in 2010 - 2017: comparison of SOLIS/VSM vector field and potential field
Ilpo I. Virtanen, Alexei A. Pevtsov, Kalevi Mursula
The line-of-sight (LOS) component of the large-scale photospheric magnetic field has been observed since the 1950s, but the daily full-disk observations of the full vector magnetic…
Explicit IMF -effect maximizes at subauroral latitudes (Dedicated to the memory of Eigil Friis-Christensen)
Lauri Holappa, Nat Gopalswamy, Kalevi Mursula
The most important parameter in the coupling between solar wind and geomagnetic activity is the -component of the interplanetary magnetic field (IMF). However, recent studies…