Radiative Hydrodynamic Simulations of the Spectral Characteristics of Solar White-light Flares

Abstract

As one of the most violent activities in the solar atmosphere, white-light flares (WLFs) are generally known for their enhanced white-light (or continuum) emission, which primarily originates in the solar lower atmosphere. However, we know little about how white-light emission is produced. In this study, we aim to investigate the response of the continua at 3600Å and 4250Å and also the H$\alpha$ and Ly$\alpha$ lines during WLFs modeled with radiative hydrodynamics simulations. We take non-thermal electron beams as the energy source for the WLFs in two different initial atmospheres and vary their parameters. Our results show that the model with non-thermal electron beam heating can clearly show enhancements in the continua at 3600Å and 4250Å as well as in the H$\alpha$ and Ly$\alpha$ lines. A larger electron beam flux, a smaller spectral index, or a penumbral initial atmosphere leads to a stronger emission increase at 3600Å, 4250Å and in the H$\alpha$ line. For the Ly$\alpha$ line, however, it is more preferably enhanced in a quiet-Sun initial atmosphere with a larger spectral index of the electron beam. It is also notable that the continua at 3600Å and 4250Å and the H$\alpha$ line exhibit a dimming at the beginning of the heating and reach their peak emissions later than the peak time of the heating function, while the Ly$\alpha$ line does not show such behaviors. These results can be served as a reference for analyzing future WLF observations.

21 pages, 10figures, 1 table, accepted for publication in RAA

References in corpus (13)

• Impulsive phase flare energy transport by large-scale Alfven waves and the electron acceleration problem
• CHIANTI - an atomic database for emission lines - Paper XV: Version 9, improvements for the X-ray satellite lines
• RH 1.5D: a massively parallel code for multi-level radiative transfer with partial frequency redistribution and Zeeman polarisation
• Radiative Hydrodynamic Models of Optical and Ultraviolet Emission from M Dwarf Flares
• Do all Flares have White Light Emission?
• New Insights into White-Light Flare Emission from Radiative-Hydrodynamic Modeling of a Chromospheric Condensation
• Hydrogen Balmer Line Broadening in Solar and Stellar Flares
• A Circular White-Light Flare with Impulsive and Gradual White-Light Kernels
• IRIS, Hinode, SDO, and RHESSI observations of a white light flare produced directly by non-thermal electrons
• Characteristics that Produce White-Light Enhancements in Solar Flares Observed by Hinode/SOT
• Modelling Mg II During Solar Flares. I. Partial Frequency Redistribution, Opacity, and Coronal Irradiation
• RADYN simulations of non-thermal and thermal models of Ellerman bombs
• The Response of the Lyman-Alpha Line in Different Flare Heating Models

Cited by in corpus (3)

• Spectral Observations and Modeling of a Solar White-light Flare Observed by CHASE
• The Lyman-$\alpha$ Emission in a C1.4 Solar Flare Observed by the Extreme Ultraviolet Imager aboard Solar Orbiter
• Predicted white-light solar flare emission from the F-CHROMA grid of models