Polarimetric Observations of a Coronal Condensation.

Saito, K.; Billings, Donald E.

doi:10.1086/147970

Cited by 48 publications

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“…It is less important for the structure and evolution of the confined plasma, which follow the field lines whatever shape they have and change little also with moderate changes of the gravity component along the field lines. First works on the accurate determination of the loop geometry date back to the 1960s (Saito and Billings, 1964 ). More specific ones take advantage of stereoscopic views allowed by huge loops during solar rotation, with the aid of magnetic field reconstruction methods.…”

Section: The Observational Frameworkmentioning

confidence: 99%

Coronal Loops: Observations and Modeling of Confined Plasma

Reale

2014

Living Rev. Solar Phys.

295

265

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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 the classification, populations, and the morphology of coronal loops, its relationship with the magnetic field, and the loop stranded structure. The section continues with the thermal properties and diagnostics of the loop plasma, according to the classification into hot, warm, and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics, hot and cool flows, and waves are illustrated. In the modeling section, some basics of loop physics are provided, supplying fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced and models are divided into those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. 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. Large-scale models including atmosphere boxes and the magnetic field are also discussed. Finally, a brief discussion about stellar coronal loops is followed by highlights and open questions.

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Section: The Observational Frameworkmentioning

confidence: 99%

Coronal Loops: Observations and Modeling of Confined Plasma

Reale

2014

Living Rev. Solar Phys.

295

265

View full text Add to dashboard Cite

show abstract

“…It is less important for the structure and evolution of the confined plasma, which follow the field lines whatever shape they have and change little also with moderate changes of the gravity component along the field lines. First works on the accurate determination of the loop geometry date back to the sixties (Saito and Billings, 1964). More specific ones take advantage of stereoscopic views allowed by huge loops during solar rotation, with the aid of magnetic field reconstruction methods.…”

Section: Geometrymentioning

confidence: 99%

Coronal Loops: Observations and Modeling of Confined Plasma

Reale¹

2010

Living Rev. Solar Phys.

148

150

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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.

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“…comparer avec les valeurs obtenues parSaito (1964).8. D6termination empirique de param6tres physiques coronauxEn supposant que les raies d'6mission sont optiquement minces (ce qui est vrai dans le cas de 5303 A~), le nombre d'atomes qui peuple le niveau 2P3/2 d'oh est issue la transition est 4n Z N. (r, o) = h~ • A~, e (r, o).…”

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Etude de l'eclipse solaire partielle du 25 Fevrier, 1971 au Pic du Midi

Rozelot

Ratier

1975

Sol Phys

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R~sum6. A partir de clich6s pris ~t l'Observatoire du Pic-du-Midi lors de l'6clipse solaire partielle du 25 F6vrier 1971, on a pu 6tudier la diffusion au voisinage imm6diat du Soleil. Les th6ories de la diffraction, rapidement esquiss6es /~ ce propos, permettent de d6terminer l'image d'un croissant 6clair6 en lumi~re incoh6rente, et de comparer les isophotes 'diffraction' ainsi calcul6s avec les lignes 'isodenses' obtenues sur les cliches.La photometric prdcise des clich6s a permis d'une part de dresser sur un secteur coronal des cartes de densit6 61ectronique, et de d6terminer d'autre part quelques param~tres physiques difficilement accessibles lots d'observations courantes, notamment taux de polarisation et densit6 d'61ectrons du premier niveau excit6 de l'ion Fe xIv. Dans ce dernier cas, on a d6velopp6 une m6thode originale de calcul pour trouver la fonction source. La superposition d'un renforcement coronal en lumi~re blanche sur une arche visible en lumi~re monochromatique conduit/t des r6sultats coh~rents sans hypotheses excessives; celles-ci sont d'ailleurs expliqudes au fur et/~ mesure et les diverses interpr6-rations sont faites, puis confront6es 5 celles trouv6es par d'autres auteurs.Abstract. The scattering in the neighbourhood of the Sun is investigated on photographs taken in Pic-du-Midi Observatory during the partial solar eclipse of february 25th 1971. Briefly mentioned, the diffraction theory is used to determine the image of a crescent with incoherent illumination, and to compare the 'diffracted' isophote curves with those drawn from the plates.An accurate photometry of the plates enables us to give charts of the electronic density in a coronal sector, and also to determine some physical quantities, values of which are rather uneasy to get from usual observations, such as the polarisation ratio and the electron density of the first Fe xIv excited level. In this last case, an original calculation was used to find the source function. A superimposition of a coronal enhancement in white light with a monochromatic arch, gives coherent results without any major assumptions. These assumptions are explained step by step and some interpretations are compared with those given by other authors.

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Polarimetric Observations of a Coronal Condensation.

Cited by 48 publications

References 0 publications

Coronal Loops: Observations and Modeling of Confined Plasma

Coronal Loops: Observations and Modeling of Confined Plasma

Coronal Loops: Observations and Modeling of Confined Plasma

Etude de l'eclipse solaire partielle du 25 Fevrier, 1971 au Pic du Midi

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