115. Investigation of White-light Emission in Circular-ribbon Flares

Contributed by Yongliang Song. Posted on November 21, 2018

A total of 90 circular-ribbon flares are identified in 8 years of SDO observations, and 33 of them are found associated with white-light enhancements, a rate higher than non-circular-ribbon flares. It is thus suggested that the fan-spine magnetic field topology and the total amount of energy release plays roles in causing white-light flares.

114. What We Learned from a Long-term Study of Sunspot Physical Parameters

Contributed by Jing Li. Posted on November 20, 2018

Physical parameters, including sunspots tilt angles, total magnetic flux, polarity pole separations, and magnetic areas, are measured for most sunspot groups in solar cycles 23 and 24. Differences between Hale and anti-Hale sunspots in separate hemispheres and cycles are studied statistically.

113. What Makes CME-producing Solar Eruptions Happen?  Insight from Coronal Jets

Contributed by Alphonse Sterling. Posted on September 28, 2018

Jets resulting from eruption of minifilaments have lots of similarities to CMEs resulting from eruptions of large-scale filaments. This study on occurrences of jets can shed light on our understanding of what causes CME eruptions.

111. Synoptic Q-Maps — Insight into the Topology of the Coronal Magnetic Field

Contributed by Todd Hoeksema. Posted on September 26, 2018

Synoptic Q-maps, which display a geometric parameter describing the squashing factor of elemental flux tubes, are computed using both HMI and MDI magnetic field observations. These maps are useful for understanding coronal configurations relevant to space weather.

110. Onset of Photospheric Impacts and Helioseismic Waves in X9.3 Solar Flare of September 6, 2017

Contributed by Alexander Kosovichev. Posted on September 17, 2018

Analysis of HMI and KONUS/WIND data shows that photospheric and helioseismic flare impacts started to develop in compact regions in close vicinity of the magnetic polarity inversion line in the pre-impulsive phase before detection of hard X-ray emission.

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.