Flare Observations

Abstract Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays beyond 1 GeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, SOHO, and more recently Hinode and SDO hav...

Full description

Bibliographic Details
Main Author: Arnold O. Benz
Format: Article
Language:English
Published: Springer 2016-12-01
Series:Living Reviews in Solar Physics
Subjects:
Online Access:http://link.springer.com/article/10.1007/s41116-016-0004-3
_version_ 1797765895712407552
author Arnold O. Benz
author_facet Arnold O. Benz
author_sort Arnold O. Benz
collection DOAJ
description Abstract Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays beyond 1 GeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, SOHO, and more recently Hinode and SDO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s) of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting magnetic reconnection as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth’s ionosphere. Flare scenarios have slowly converged over the past decades, but every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.
first_indexed 2024-03-12T20:17:45Z
format Article
id doaj.art-9adca529ed334efc85874eacab27b423
institution Directory Open Access Journal
issn 2367-3648
1614-4961
language English
last_indexed 2024-03-12T20:17:45Z
publishDate 2016-12-01
publisher Springer
record_format Article
series Living Reviews in Solar Physics
spelling doaj.art-9adca529ed334efc85874eacab27b4232023-08-02T01:14:11ZengSpringerLiving Reviews in Solar Physics2367-36481614-49612016-12-0114115910.1007/s41116-016-0004-3Flare ObservationsArnold O. Benz0Institute for Astronomy, ETHAbstract Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays beyond 1 GeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, SOHO, and more recently Hinode and SDO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s) of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting magnetic reconnection as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth’s ionosphere. Flare scenarios have slowly converged over the past decades, but every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.http://link.springer.com/article/10.1007/s41116-016-0004-3ReconnectionX-ray emissionFlare radio emissionParticle accelerationMagnetic energy release
spellingShingle Arnold O. Benz
Flare Observations
Living Reviews in Solar Physics
Reconnection
X-ray emission
Flare radio emission
Particle acceleration
Magnetic energy release
title Flare Observations
title_full Flare Observations
title_fullStr Flare Observations
title_full_unstemmed Flare Observations
title_short Flare Observations
title_sort flare observations
topic Reconnection
X-ray emission
Flare radio emission
Particle acceleration
Magnetic energy release
url http://link.springer.com/article/10.1007/s41116-016-0004-3
work_keys_str_mv AT arnoldobenz flareobservations