The Statistical Relationship between White-light Emission and Photospheric Magnetic Field Changes in Flares

Continuum emission, also called white-light emission (WLE), and permanent changes of the magnetic field (ΔBLOS) are often observed during solar flares. However, their relation and precise mechanisms are still unknown. We study statistically the relationship between ΔBLOS and WLE during 75 solar flar...

Full description

Saved in:
Bibliographic Details
Published in:The Astrophysical journal 2020-12, Vol.904 (2), p.96
Main Authors: Castellanos Durán, J. Sebastián, Kleint, Lucia
Format: Article
Language:English
Subjects:
Astrophysics
Blackbody
Continuum radiation
Light emission
Magnetic fields
Mathematical analysis
Photosphere
Photospheric magnetic fields
Power law
Solar flares
Solar magnetic fields
Solar photosphere
Solar white-light flares
Stellar flares
White light
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Continuum emission, also called white-light emission (WLE), and permanent changes of the magnetic field (ΔBLOS) are often observed during solar flares. However, their relation and precise mechanisms are still unknown. We study statistically the relationship between ΔBLOS and WLE during 75 solar flares of different strengths and locations on the solar disk. We analyze SDO/HMI data and determine for each pixel in each flare if it exhibited WLE and/or ΔBLOS. We then investigate the occurrence, strength, and spatial size of the WLE, its dependence on flare energy, and its correlation to the occurrence of ΔBLOS. We detected WLE in 44/75 flares and ΔBLOS in 59/75 flares. We find that WLE and ΔBLOS are related, and their locations often overlap between 0% and 60%. Not all locations coincide, thus potentially indicating differences in their origin. We find that the WL area is related to the flare class by a power law, and extend the findings of previous studies, that the WLE is related to the flare class by a power law, to also be valid for C-class flares. To compare unresolved (Sun-as-a-star) WL measurements with our data, we derive a method to calculate temperatures and areas of such data under the blackbody assumption. The calculated unresolved WLE areas improve, but still differ to the resolved flaring area by about a factor of 5-10 (previously 10-20), which could be explained by various physical or instrumental causes. This method could also be applied to stellar flares to determine their temperatures and areas independently.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ab9c1e