A circular white-light flare with impulsive and gradual white-light kernels

Area of Science:

• Solar Physics
• Plasma Astrophysics
• Stellar Flares

Background:

• White-light flares, characterized by optical continuum emissions, are rare solar events.
• They impose strict constraints on energy transport and atmospheric heating during solar eruptions.
• Understanding these flares is crucial for comprehending solar atmospheric dynamics.

Purpose of the Study:

• To analyze a well-observed, nearly circular white-light flare event on March 10, 2015.
• To investigate the simultaneous occurrence of impulsive and gradual white-light kernels.
• To evaluate the sufficiency of current models in explaining observed flare phenomena.

Main Methods:

• Utilized data from the Optical and Near-infrared Solar Eruption Tracer (ONSET) and the Solar Dynamics Observatory (SDO).
• Analyzed observational data to identify and characterize different types of white-light flare kernels.
• Compared observational results with predictions from established solar flare models.

Main Results:

• Observed a nearly circular white-light flare with simultaneous impulsive and gradual emission kernels.
• The thick-target model adequately explains impulsive kernels.
• The gradual kernels could not be fully explained by the thick-target model alone.

Conclusions:

• The presence of gradual white-light kernels suggests limitations in the standard thick-target model.
• Alternative or supplementary mechanisms, such as soft X-ray backwarming or Alfvén waves, may contribute to gradual emissions.
• Further research and observations are required to fully understand the origin of gradual white-light kernels in solar flares.