2017/11/30 by Soumitra Hazra, Sushant S. Mahajan, William Keith Douglas Jr. +3 · 6 citations
Chemistry · Computer Science · Mathematics · Medicine · Physics and Astronomy · #Astrophysics #Biology #Chemistry #Chirality (physics) #Mathematics #Paleontology #Particle physics #Physics #Preference #Protein filament #Radiation Therapy and Dosimetry #Sinistral and dextral #Solar Radiation and Photovoltaics #Solar and Space Plasma Dynamics #Statistics #Variation (astronomy) #astro-ph.SR
paper · pdf · doi:10.3847/1538-4357/aadb42
published in The Astrophysical Journal 865(2), 108 (IOP Publishing) · Accepted in Astrophysical Journal
openalex created_date 2017/12/04 · openalex publication_date 2018/09/27 · arxiv created 2018/10/05 · arxiv updated 2018/10/10 · openalex updated_date 2026/08/05
Abstract It is well known that solar filaments are features in the solar atmosphere that show a hemispheric preference in their chirality. The hemispheric preference is such that the dextral chirality dominates in the northern hemisphere while the sinistral chirality dominates in the southern. Determining the strength and cyclic variation of the degree of this hemispheric preference however, is challenging and tedious, and thus, needs to be automated. In this paper, we follow Dr. Pietro Bernasconi’s algorithm to detect filament chirality with two parallel channels of application. The algorithm is applied to H-alpha images with the “Advanced Automated Filament Detection and Characterization Code” and the full algorithm (including the detection of filaments and tracking) is explained to the human observer who determines the chirality of the solar filament. We have conducted this exercise on the data during the month of August from years 2000 to 2016 and we found that 83% of our visually determined filaments follow the hemispheric chirality preference, while 58% of automatically determined filaments follow it. Our visually compiled results have over 90% agreement with those of Pevtsov et al., yet the visually determined chiralities of filaments disagree with the automated determinations significantly. We find that the hemispheric preference remained the same between solar cycles 23 and 24, but the preference is very difficult to determine during the solar minimum of 2008–2010 primarily due to the absence of filaments.