This review covers the techniques, observations, and inferences of solar flare spectroscopy. It is not a spectroscopist's view of solar flares but rather a solar flare physicist's view of spectroscopy. Spectroscopy is carried out across the electromagnetic spectrum, but this review emphasizes the optical to soft X-ray part of the spectrum and discusses results from spectroscopy applied to the preflare, impulsive, and gradual phases, as well as a few highlights from modeling. ▪ The main spectroscopic signatures of the preflare phase are line broadening in optically thin ultraviolet to soft X-ray lines and small Doppler shifts in active region filaments that are becoming unstable. ▪ In the impulsive phase, fast upflows of heated plasma into the corona and slow downflows of cooler chromospheric plasma take place at the sites of strong chromospheric energy deposition. ▪ Radiation-hydrodynamic modeling of optically thick spectral lines gives a picture of an impulsive-phase chromosphere with a dense, heated layer deep in the atmosphere and an overlying, downward moving condensation that is partially optically thin. ▪ Gradual-phase observations show us the heated coronal plasma cooling and draining but also provide evidence for ongoing slow energy input and slow upflows in other locations. ▪ Interesting hints of non-Maxwellian and nonequilibrium plasmas have been found, along with possible evidence of plasma turbulence from line broadening.

Lyndsay Fletcher

Annual Review of Astronomy and Astrophysics

自 1963 年出版的《天文学和天体物理学年度评论》涵盖了天文学和天体物理学领域的重大发展，包括：太阳；太阳系和系外行星；星星;星际介质；星系和星系；活跃的星系核；宇宙学；和仪器和技术，以及新研究领域的发展历史。

The Annual Review of Astronomy and Astrophysics has been published since 1963, covering significant developments in the fields of astronomy and astrophysics. This includes topics such as the Sun, the solar system and exoplanets, stars, interstellar medium, galaxies and their evolution, active galactic nuclei, cosmology, as well as advancements in instruments and techniques. The journal also discusses the historical development of new research areas.

《Annual Review of Astronomy and Astrophysics》自1963年出版，涵盖了天文学和天体物理学领域的重要发展，包括太阳、太阳系及系外行星、恒星、星际介质、星系及其演化、活跃星系核、宇宙学，以及相关仪器和技术的进展。此外，期刊还探讨了新研究领域的发展历程。

Category	Quartile
物理与天体物理	1
物理与天体物理, 天文与天体物理	1

Solar Flare Spectroscopy

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Journal Info

Category	Quartile
ASTRONOMY & ASTROPHYSICS	1