Tag Archives: dynamo

128. Evolution of Magnetic Helicity in Solar Cycle 24

Contributed by V.V. Pipin. Posted on June 25, 2019

A novel approach is developed to reconstruct the surface magnetic helicity density for the Sun or sun-like stars. The method is applied on the SDO/HMI-observed vector field synoptic data to study the temporal evolution of the Sun’s magnetic helicity density during Solar Cycle 24.

109. How Many Active Regions Are Necessary to Predict the Solar Dipole Moment?

Contributed by Tim Whitbread. Posted on September 10, 2018

To assess the impact of active regions to the axial dipole moment, the authors isolate the contribution of individual regions for Cycles 21, 22, and 23 using a surface flux transport model, and find that although the top ~10% of contributors tend to define sudden large variations in the dipole moment, the cumulative contribution of many weaker regions cannot be ignored.

98. Solar-Cycle Variations of Meridional Flows in the Solar Convection Zone with Helioseismic Methods

Contributed by Chia-Hsien Lin. Posted on May 18, 2018

Meridional flows during the solar minimum and maximum years are derived using 14 years of SOHO/MDI data. The flows changed significantly from the minimum to the maximum, and major changes were associated with the active latitudes.

91. On The Origin of the Double-Cell Meridional Circulation in the Solar Convection Zone

Contributed by Valery Pipin. Posted on March 19, 2018

It is demonstrated that when taking into account of the radial inhomogeneity of the Coriolis number, the solar-like differential rotation and the double-cell meridional circulation can both be reproduced by the mean-field model.

89. Information theoretic approach to discovering causalities in solar cycle

Contributed by Simon Wing. Posted on March 15, 2018

Various observable, such as polar field, meridional flow, and sunspot number, are examined to identify information flow, causality, and time delay between them during solar cycles. It is expected that this analysis can provide observational constraints on solar cycle models and theories.