Unveiling Spatiotemporal Properties of the Quasi-periodic Pulsations in the Balmer Continuum at 3600 Å in an X-class Solar White-light Flare

Abstract

Quasi-periodic pulsations (QPPs) in the Balmer continuum of solar white-light flares (WLFs) are rarely reported, and accurately pinpointing the spatial source of flaring QPPs remains a significant challenge. We present spatiotemporal characteristics of QPPs of an X2.8 two-ribbon solar WLF (SOL2023-12-14T17:02), which was well observed by the White-light Solar Telescope (WST) aboard the Advanced Space-based Solar Observatory, with high-cadence imaging (1--2 s) in the Balmer continuum at 3600 Å. Combined with additional multi-instrument data, we find that the enhancement of the WLF in both Balmer and Paschen continua shows strong spatiotemporal correlation with hard X-ray (HXR) emissions. Notably, the pulses in the WST Balmer continuum exhibited a near-zero time lag with most HXR pulses, whereas soft X-ray and extreme ultraviolet emissions showed a lag of 2--3 s. Interestingly, quasi-harmonic QPPs with periods of $\sim$11 s and $\sim$20 s were observed in multiple wavelengths in the rising phase of the white-light continuum. Furthermore, we employed Fourier transform to spatially locate the QPPs around 11 and 20 s, revealing that they primarily originated from the east flare ribbon, which exhibited the most substantial continuum enhancement. More interestingly, we find that the west ribbon contributed significantly to the 11-second QPP but had a weaker contribution to the 20-second QPP. Moreover, the occurrence of quasi-harmonic QPPs is temporally coincident with the rapid elongation and separation motions of flare ribbons. Possible mechanisms for the quasi-harmonic QPPs have been discussed. These observations provide valuable insights into QPP modeling for solar and stellar flares.

19 pages, 6 figures, and two tables

References in corpus (17)

• The Solar Orbiter mission -- Science overview
• The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs -- Space-weather HMI Active Region Patches
• MPI-AMRVAC 3.0: updates to an open-source simulation framework
• Soft X-ray Pulsations in Solar Flares
• Statistical Study of GOES X-ray Quasi-Periodic Pulsations in Solar Flares
• The LYRA Instrument Onboard PROBA2: Description and In-Flight Performance
• Elongation of Flare Ribbons
• The periodic variations of a white-light flare observed with ULTRACAM
• Quasi-Periodic Pulsations during the Impulsive and Decay phases of an X-class Flare
• Quasi-periodic oscillations in flares and coronal mass ejections associated with magnetic reconnection
• A Circular White-Light Flare with Impulsive and Gradual White-Light Kernels
• A Compact Source for Quasi-Periodic Pulsation in an M-class Solar Flare
• Comparative Analysis of Non-thermal Emissions and Study of Electron Transport in a Solar Flare
• Forward Modeling of SDO/AIA and X-Ray Emission from a Simulated Flux Rope Ejection
• Spectral Observations and Modeling of a Solar White-light Flare Observed by CHASE
• Localizing short-period pulsations in hard X-rays and Gamma-rays during an X9.0 flare
• Very long-periodic pulsations detected simultaneously in a white-light flare and sunspot penumbra

Cited by in corpus (3)

• High-resolution Observations of a C9.3 White-light Flare and Its Impact on the Solar Photosphere
• Detecting fast-variation pulsations in solar hard X-ray and radio emissions
• Time-dependent Turbulent Electron Acceleration and Transport in Solar Flares