Coronal Loops: Observations and Modeling of Confined Plasma

By Fabio Reale. 2010

158 citations recorded by the source corpus.

Coronal loops are the building blocks of the X-ray bright solar corona. They owe their brightness to the dense confined plasma, and this review focuses on loops mostly as structures confining plasma. After a brief historical overview, the review is divided into two separate but not independent parts: the first illustrates the observational framework, the second reviews the theoretical knowledge. Quiescent loops and their confined plasma are considered, and therefore topics such as loop oscillations and flaring loops (except for non-solar ones which provide information on stellar loops) are not specifically addressed here. The observational section discusses loop classification and populations, and then describes the morphology of coronal loops, its relationship with the magnetic field, and the concept of loops as multi-stranded structures. The following part of this section is devoted to the characteristics of the loop plasma and of its thermal structure in particular, according to the classification into hot, warm, and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics and flows are illustrated. In the modeling section some basics of loop physics are provided, supplying some fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced and models are distinguished between those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. Then, more specific discussions address modeling the loop fine structure and the plasma flowing along the loops. Special attention is devoted to the question of loop heating, with separate discussion of wave (AC) and impulsive (DC) heating. Finally, a brief discussion about stellar X-ray emitting structures related to coronal loops is included and followed by conclusions and open questions.

Subfields: Astronomy and Astrophysics, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/a6b6ac2ea4b29503aed300ec52ada7fe33eeab31

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Citations in the corpus

Magnetohydrodynamic Oscillations in the Solar Corona and Earth’s Magnetosphere: Towards Consolidated Understanding (2016, background): “The high temperature of the coronal plasma constitutes the “coronal heating problem”: it is commonly accepted that it is connected with the conversion of the magnetic energy, while the specific mechanisms are still intensively debated (see, e.g. Reale 2014, for a recent review).”
The multi-thermal emission in solar active regions (2013, background): “For recent reviews, see e.g. Klimchuk (2010) and Reale (2010).”
Solar Orbiter (2012, background): “In particular, both turbulence and magnetic reconnection are implicated theoretically and observationally in coronal heating and acceleration (for reviews, see, e.g., Klimchuk, 2006 and Reale, 2010).”
The magnetic field in the solar atmosphere (2014, background): “The lower and upper limits are representative of cool and flaring loops, respectively (Reale 2010).”
Coronal Heating by MHD Waves (2020, background): “As the local density in closed loops is related to the magnitude of the heating (see e.g. Klimchuk 2006; Reale 2014), the phase mixing heating profile is not consistent with the heating profile to sustain the density profile.”
The Solar Orbiter mission (2020, background): “…mechanisms proposed attribute key roles to the Sun’s convective motions in the photosphere and its magnetic field, which can release energy via magnetic reconnection and/or guide waves that might dissipate energy in the corona (for reviews, see Klimchuk 2006; Reale 2010; Cranmer & Winebarger 2019).”
The FIP and Inverse FIP Effects in Solar and Stellar Coronae (2015, methodology): “We concentrate solely on the fractionation, referring the reader to the reviews of Reale (2014) for the properties of plasma in closed coronal loops, and to Marsch (2006), Cranmer (2009) and Ofman (2010) for the physics of the acceleration of the fractionated gas into the fast and slow speed solar…”