Abstract Details


Name: Manjunath Hegde
Affiliation: Indian Institute of Astrophysics
Conference ID: TVS202510301
Title: A Declining Trend in Sunspot Group Tilt Angles Over Three and half Solar Cycles: 21 -- 24
Authors and Co-Authors: Ravindra B, Hiremath K M
Abstract Type: Contributory Presentation
Abstract: The tilt angle, defined as the angle between the line connecting the two polarities of a sunspot group and the solar equator, plays a critical role in linking the Sun’s global magnetic field and is a key parameter in dynamo models. This study examines the long-term characteristics of sunspot group tilt angles using data from the Debrecen Photoheliographic Database (DPD), covering three and a half solar cycles (1974–2013). Using tilt angles provided in the DPD catalog, we compute annual averages and apply weighted linear regression to assess long-term trends, along with wavelet transform analysis to identify short-term periodicities. Our analysis reveals a significant, consistent decrease in the magnitude of sunspot tilt angles, with an average yearly decline of approximately \(0.076 \pm 0.007\) degrees. Additionally, a wavelet analysis indicates a short-term 5--6 year periodicity. These findings suggest complex underlying magnetic field dynamics and may have significant implications for understanding solar cycle modulation and related phenomena.