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Astrophysics Research Centre

School of Mathematics and Physics


Century long series of solar filaments: key properties for solar cycle studies

  • Submitted by: Kirill Kuzanyan, IZMIRAN, Russian Academy of Sciences, Moscow
  • Authors: A. G. Tlatov, K. M. Kuzanyan, V. V. Vasilieva
  • Session: Monday afternoon posters.

We carry out uniform study of distribution of solar filaments using the data from Meudon Observatory 1919-2003 together with Kislovodsk Mountain Astronomical Station 1979-2014. We scanned and digitized the observed H-alpha synoptic maps, isolating and digitizing filament locations. Data on each filament contain information of the location, length, area, position and other geometric characteristics. We obtained the distributions of the number and the length of filaments with time as well as their latitudinal drift with solar cycle. We also analyzed of the longitudinal distribution, in particular the asymmetry with respect to the northern and southern hemispheres, and other characteristics of filaments.

We also obtained the tilt angles with respect to the equator. On average, western ends of the filament structures are closer to the poles than eastern ones by some 10 degrees in latitude, which we have defined as positive tilts. To the contrary, in the sub-polar regions with latitudes greater than 50 degrees the filament tilt angles are mainly negative. The portion of filaments in the middle-latitude is not large (less than 30%).

The tilt angles vary with the phase of solar cycle attaining their maximum at sunspot maximum activity phase. The highest values for low-latitudinal filaments (below 40 degrees from the equator) have been attained in the middle of 20th century in solar cycles 18-19 at the time of maximum activity.

We hereby propose using statistical properties of solar filaments as an additional coherent measure for manifestation of the solar cycle which covers all latitudes and is systematically calibrated almost for a century long available data series.

public/hinode9/schedule/session-02p/v0050.txt · Last modified: 2015/07/30 00:45 (external edit)


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