Tag Archives: flares

138. Electric Current Neutralization in Solar Active Regions and Its Relation to Eruptive Activity

Contributed by Ellis Avallone. Posted on March 11, 2020

Electric current neutralization, which measures the ratio of direct current and return current inside active regions (ARs), is studied for a total of 30 AR samples. It is found that flare-productive ARs are more likely to exhibit non-neutralized currents than those flare-quiet ARs.

136. The Trigger Mechanism of Recurrent Solar Active Region Jets Revealed by the Magnetic Properties of a Coronal Geyser Site

Contributed by Alin Paraschiv. Posted on February 27, 2020

This study explores the magnetic triggers of recurrent active region jets. Both widely debated triggers, namely, flux cancellation and flux emergence, are associated alternatively to the apparently homologous jets.

135. Serial Flaring in an Active Region: Exploring Why Only One Flare is Eruptive

Contributed by Magnus Woods. Posted on February 26, 2020

Of three consecutive flares that occurred in a same active region within 4 hours, why were two non-eruptive and one eruptive? Non-linear force-free modeling suggest that breakout reconnection during the first two flares weakened the overlying field, allowing the flux rope to erupt in the third.

121. The Origin of Major Solar Activity: Collisional Shearing between Nonconjugated Polarities of Multiple Bipoles Emerging within Active Regions

Contributed by Georgios Chintzoglou. Posted on February 28, 2019

Magnetic flux of opposite polarities belonging to two different emerging/emerged bipoles inside multipolar magnetic regions, can experience “collisional shearing”, a process resulting in strong shearing and fast cancellation of magnetic flux near the polarity inversion line. This type of flux cancellation is found to be the cause of a succession of major flares and CMEs in complex active regions.

119. Roles of Photospheric Motions and Flux Emergence in the Major Solar Eruption on 2017 September 6

Contributed by Rui Wang. Posted on January 31, 2019

Both magnetic flux emergence and shearing flows occurred before the X9.3 flare on 2017 September 6. This analysis shows that shearing flows played a more significant role in leading to the helicity and electric currents buildup before the major eruption.

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.

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.

96. Evaluation of Applicability of a Flare Trigger Model
 Based on a Comparison of Geometric Structures


Contributed by Yumi Bamba. Posted on April 23, 2018

A sample of 32 flare events are analyzed to evaluate how these events agree with a flare-triggering model, which examines shear angles of large-scale magnetic field and small-scale dipole field during the flares’ precursor brightening.