By analyzing resolved solar observations, we reveal significant temporal evolution in white-light flare area and temperature. Based on these findings, our new energy estimation method systematically yields lower flare energies, prompting a re-examination of classical macroscopic scaling laws.
Using SDO/HMI white-light continuum observations and GOES Lyα and SXR irradiance, this study investigates 69 solar white-light flares to examine their emission properties, including enhancement, peak-time ordering, evolutionary timescales, and relationships between the emission parameters and radiated energy.
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.
NOAA active regions 13664/8, the solar source region responsible for the May 2024 extreme geomagnetic disturbances that caused the largest geomagnetic storm since 2003, broke the record of magnetic flux emergence rate in the SDO era.
A survey of how many off-limb white-light events were observed by the SDO/HMI was conducted, and a catalogue is published online with real-time updates.
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.
Another white-light flare was captured by HMI off the solar limb, this time with materials seen ejected from the Sun. A fraction of the ejecta was seen falling back to the Sun.
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.
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.
A strong limb flare observed simultaneously by the SDO/AIA and SDO/HMI, which is very rare, allows the authors to study the emission mechanism for white-light flare loops, as well as estimate the electron densities along the flare loop.