Periodic Variations in Visible Light Brightness as Tracers of Fine Coronal Structures

Fuente: arXiv
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Auteurs principaux: Alzate, Nathalia, Di Matteo, Simone
Format: Preprint
Publié: 2025
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author Alzate, Nathalia
Di Matteo, Simone
author_facet Alzate, Nathalia
Di Matteo, Simone
contents The quiescent or dynamic nature of fine scale ray-like features in the sun corona, observed in visible light, is still an open question. Here, we show that most of daily and hourly periodic variations in visible light brightness of the high corona (up to 15 Rs) are aligned to the tip of streamers and are consistent with the periodicity of plasma release from simulations of tearing-induced magnetic reconnection at the heliospheric current sheet. The areas in which we detect periodicities can be used as tracers of non-quiescent fine coronal rays. This also allows their distinction from coronal rays more likely to be real quiescent features or associated with smaller and/or faster unresolved brightness variations. In the low- and middle-corona (down to 1.4 Rs) similar brightness variations are observed along loop-like and cusp-like features marking boundaries of streamers which then connect to radial features in the high corona. This suggests the presence of additional mechanisms in the low- and middle-corona periodically releasing density structures in the solar wind. The periodicity distributions show a solar cycle modulation with shorter periods (smaller structures) during solar maximum. Periodicities are observed within streamers during solar minimum, but are visible at all latitudes, even extending radially from the poles, during solar maximum.
format Preprint
id arxiv_https___arxiv_org_abs_2509_12009
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Periodic Variations in Visible Light Brightness as Tracers of Fine Coronal Structures
Alzate, Nathalia
Di Matteo, Simone
Solar and Stellar Astrophysics
Instrumentation and Methods for Astrophysics
The quiescent or dynamic nature of fine scale ray-like features in the sun corona, observed in visible light, is still an open question. Here, we show that most of daily and hourly periodic variations in visible light brightness of the high corona (up to 15 Rs) are aligned to the tip of streamers and are consistent with the periodicity of plasma release from simulations of tearing-induced magnetic reconnection at the heliospheric current sheet. The areas in which we detect periodicities can be used as tracers of non-quiescent fine coronal rays. This also allows their distinction from coronal rays more likely to be real quiescent features or associated with smaller and/or faster unresolved brightness variations. In the low- and middle-corona (down to 1.4 Rs) similar brightness variations are observed along loop-like and cusp-like features marking boundaries of streamers which then connect to radial features in the high corona. This suggests the presence of additional mechanisms in the low- and middle-corona periodically releasing density structures in the solar wind. The periodicity distributions show a solar cycle modulation with shorter periods (smaller structures) during solar maximum. Periodicities are observed within streamers during solar minimum, but are visible at all latitudes, even extending radially from the poles, during solar maximum.
title Periodic Variations in Visible Light Brightness as Tracers of Fine Coronal Structures
topic Solar and Stellar Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2509.12009