Category Archives: solar flares

202. Optimization of Solar White-Light Flare Identification Methods and Its Application

Contributed by Yijun Hou. Posted on September 24, 2024

A new method was developed to identify white-light flares (WLFs) observed in SDO/HMI continuum intensity. The new method is able to identify around 30% of C-class flares (and more percentage in stronger flares) having white light brightening associated with them, greatly expanding the total number of WLFs observed by HMI. The increased number of detections would help a statistical study of the properties of WLFs.

184. Measuring the Compactness of Active Regions

Contributed by Kelvin Moresi. Posted on August 10, 2022

Compactness is one geometric property of a sunspot group that has not yet been systematically quantified. We calculate the compactness of a small sample of δ-spots and β-spots using a minimum bounding circle. On average, the δ-spots are found to be more than twice as compact as the β-spots.

167. White-light Continuum Observation of the Off-limb Loops of the SOL2017-09-10 X8.2 Flare: Temporal and Spatial Variations

Contributed by Junwei Zhao. Posted on October 28, 2021

An unprecedented observation of a limb flare in HMI’s white-light continuum shows that the white-light intensity at the post-flare loop-top continues to grow for 16 more minutes while UV/EUV intensities decay. Both the WL/UV intensity and the EUV intensities show quasi-periodic pulsations with a period close to 8.0 and 6.8 minutes, respectively.

140. Solar Flare Predictive Features Derived from Polarity Inversion Line Masks in Active Regions Using an Unsupervised Machine Learning Algorithm

Contributed by Jingjing Wang. Posted on May 4, 2020

An unsupervised machine-learning algorithm is used on selected features derived from the polarity inversion lines (PIL) mask and difference PIL mask. It is found these features are effective in predicting flaring occurrences.

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.

90. A Comparative Study of the Eruptive and Non-Eruptive Flares Produced by the Largest Active Region of Solar Cycle 24

Contributed by Ranadeep Sarkar. Posted on March 18, 2018

AR12192, the largest active region in Solar Cycle 24, produced 6 X-class flares, but none of them were associated with a CME. However, a much weaker flare, of M4.0-class, was associated with a CME. Magnetic field and morphological changes are analyzed during these flares to understand why this is the case.