Observational analysis of Lyα emission in equivalent-magnitude solar flares

Harry J. Greatorex; Ryan O. Milligan; Phillip C. Chamberlin

doi:10.3847/1538-4357/acea7f

Observational analysis of Lyα emission in equivalent-magnitude solar flares

Harry J. Greatorex^*
, Ryan O. Milligan
, Phillip C. Chamberlin

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

12 Citations (Scopus)

129 Downloads (Pure)

Abstract

The chromospheric Lyα line of neutral hydrogen (1216 Å) is the most intense emission line in the solar spectrum, yet until recently observations of flare-related Lyα emission have been scarce. Here, we examine the relationship between nonthermal electrons accelerated during the impulsive phase of three M3 flares that were co-observed by RHESSI, GOES, and the Solar Dynamics Observatory, and the corresponding response of the chromosphere in Lyα. Despite having identical X-ray magnitudes, these flares showed significantly different Lyα responses. The peak Lyα enhancements above the quiescent background for these flares were 1.5%, 3.3%, and 6.4%. However, the predicted Lyα enhancements from FISM2 were consistently

Original language	English
Article number	120
Number of pages	12
Journal	The Astrophysical Journal
Volume	954
Issue number	2
Early online date	29 Aug 2023
DOIs	https://doi.org/10.3847/1538-4357/acea7f
Publication status	Published - 10 Sept 2023

Keywords

Solar chromosphere
Solar physics
Solar x-ray flares
Active sun
Solar flares
Solar extreme ultraviolet emission
Spectroscopy

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10.3847/1538-4357/acea7fLicence: CC BY

Observational analysis of Lyα Emission in equivalent-magnitude solar flares
Copyright 2023 the authors. This is an open access Creative Commons Attribution-NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits use, distribution and reproduction for non-commercial purposes, provided the author and source are cited.
Final published version, 4.01 MBLicence: CC BY

Observational analysis of Lyman-alpha emission in solar flares
Greatorex, H. J. (Author), Milligan, R. (Supervisor) & Mathioudakis, M. (Supervisor), Dec 2025
Student thesis: Doctoral Thesis › Doctor of Philosophy

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title = "Observational analysis of Lyα emission in equivalent-magnitude solar flares",

abstract = "The chromospheric Lyα line of neutral hydrogen (1216 {\AA}) is the most intense emission line in the solar spectrum, yet until recently observations of flare-related Lyα emission have been scarce. Here, we examine the relationship between nonthermal electrons accelerated during the impulsive phase of three M3 flares that were co-observed by RHESSI, GOES, and the Solar Dynamics Observatory, and the corresponding response of the chromosphere in Lyα. Despite having identical X-ray magnitudes, these flares showed significantly different Lyα responses. The peak Lyα enhancements above the quiescent background for these flares were 1.5\%, 3.3\%, and 6.4\%. However, the predicted Lyα enhancements from FISM2 were consistently ",

keywords = "Solar chromosphere, Solar physics, Solar x-ray flares, Active sun, Solar flares, Solar extreme ultraviolet emission, Spectroscopy",

author = "Greatorex, \{Harry J.\} and Milligan, \{Ryan O.\} and Chamberlin, \{Phillip C.\}",

year = "2023",

month = sep,

day = "10",

doi = "10.3847/1538-4357/acea7f",

language = "English",

volume = "954",

journal = "The Astrophysical Journal",

issn = "0004-637X",

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T1 - Observational analysis of Lyα emission in equivalent-magnitude solar flares

AU - Greatorex, Harry J.

AU - Milligan, Ryan O.

AU - Chamberlin, Phillip C.

PY - 2023/9/10

Y1 - 2023/9/10

N2 - The chromospheric Lyα line of neutral hydrogen (1216 Å) is the most intense emission line in the solar spectrum, yet until recently observations of flare-related Lyα emission have been scarce. Here, we examine the relationship between nonthermal electrons accelerated during the impulsive phase of three M3 flares that were co-observed by RHESSI, GOES, and the Solar Dynamics Observatory, and the corresponding response of the chromosphere in Lyα. Despite having identical X-ray magnitudes, these flares showed significantly different Lyα responses. The peak Lyα enhancements above the quiescent background for these flares were 1.5%, 3.3%, and 6.4%. However, the predicted Lyα enhancements from FISM2 were consistently

AB - The chromospheric Lyα line of neutral hydrogen (1216 Å) is the most intense emission line in the solar spectrum, yet until recently observations of flare-related Lyα emission have been scarce. Here, we examine the relationship between nonthermal electrons accelerated during the impulsive phase of three M3 flares that were co-observed by RHESSI, GOES, and the Solar Dynamics Observatory, and the corresponding response of the chromosphere in Lyα. Despite having identical X-ray magnitudes, these flares showed significantly different Lyα responses. The peak Lyα enhancements above the quiescent background for these flares were 1.5%, 3.3%, and 6.4%. However, the predicted Lyα enhancements from FISM2 were consistently

KW - Solar chromosphere

KW - Solar physics

KW - Solar x-ray flares

KW - Active sun

KW - Solar flares

KW - Solar extreme ultraviolet emission

KW - Spectroscopy

U2 - 10.3847/1538-4357/acea7f

DO - 10.3847/1538-4357/acea7f

M3 - Article

SN - 0004-637X

VL - 954

JO - The Astrophysical Journal

JF - The Astrophysical Journal

IS - 2

M1 - 120

ER -

Observational analysis of Lyα emission in equivalent-magnitude solar flares

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Student theses

Observational analysis of Lyman-alpha emission in solar flares

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