A morphological study of the solar granulation

Namba, O.; Diemel, W. E.

doi:10.1007/bf00224895

Cited by 40 publications

(8 citation statements)

References 5 publications

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“…What do the best constrained spicule data -those for type II spicules -imply if all such spicules are interpreted as warped sheets? At any time there are ≈ 6 × 10 6 granules on the Sun (Namba & Diemel 1969), and, as listed in the table and discussed further below, ∼ 2 × 10 7 type II spicules (Judge & Carlsson 2010). With these data we would need on average 4 warps per granule, or 1600 per 20Mm diameter supergranule.…”

Section: Spicules and Fibrils As Sheetsmentioning

confidence: 99%

Thermal Fine Structure and Magnetic Fields in the Solar Atmosphere: Spicules and Fibrils

Judge

Tritschler

Low

2011

ApJ

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The relationship between observed structures in the solar atmosphere and the magnetic fields threading them is known only for the solar photosphere, even then imprecisely. We suggest that some of the fine structure in the more tenuous chromosphere and corona-specifically some populations of spicules and fibrilscorrespond to warps in 2D sheet-like structures, as an alternative to conventional interpretations in terms of tube-like structures. The sheets are perhaps related to magnetic tangential discontinuities, which Parker has argued arise naturally in low-β conditions. Some consequences of this suggestion, if it can be confirmed, are discussed.

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Section: Spicules and Fibrils As Sheetsmentioning

confidence: 99%

Thermal Fine Structure and Magnetic Fields in the Solar Atmosphere: Spicules and Fibrils

Judge

Tritschler

Low

2011

ApJ

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“…This spectrum is determined by the spatial and temporal spectra of the turbulent motions (Musielak et al, 1994). Empirically, the spatial spectrum of solar convection peaks on scales of 1-2 Mm (Namba and Diemel, 1969). The temporal spectrum of solar convection peaks at long periods (P = 700-800 s: the typical granule lifetime), with rms velocity amplitudes of 0.5-0.6 km/s.…”

Section: Chromosphere Versus Corona: Hydrodynamics Versus Mhdmentioning

confidence: 99%

MHD turbulence and heating of the open field-line solar corona

Matthaeus

Mullan

Dmitruk

et al. 2003

Nonlin. Processes Geophys.

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Abstract. This paper discusses the possibility that heating of the solar corona in open field-line regions emanating from coronal holes is due to a nonlinear cascade, driven by low-frequency or quasi-static magnetohydrodynamic fluctuations. Reflection from coronal inhomogeneities plays an important role in sustaining the cascade. Physical and observational constraints are discussed. Kinetic processes that convert cascaded energy into heat must occur in regions of turbulent small-scale reconnection, and may be similar in some respects to ion heating due to intense electron beams observed in the aurora.

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“…As the smallest convective elements, many properties of granules have been carefully studied. The observed size of granules excluding the surrounding dark lanes ranges from approximately 0 ′′ .2 (the limit of ground-based observations) to approximately 3 ′′ .4 (Peter N Brandt 2000), and the mean granular size amounts to 1 ′′ .1 (Namba & Diemel 1969), or 1 ′′ .35 (Bray et al 1984). The mean cell size of the granular elements including one-half of the surrounding dark lanes is 1 ′′ .94 according to Bray & Loughhead (1977), and 1 ′′ .76 according to Roudier & Muller (1986).…”

Section: Introductionmentioning

confidence: 99%

Vector Magnetic Fields of Solar Granulation

Jin

Wang

Zhao

2008

ApJ

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Observations of quiet Sun from the Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) aboard the Hinode spacecraft would reveal the magnetic characters of the solar photosphere. By making use of the deep mode observations of three quiet regions, we have statistically studied the vector magnetic fields of solar granulation. More than 2000 normal granules are manually selected to form a sample. It is recognized that some granules are even darker than the mean photosphere in intensity, and there is a linear correlation between intensity and Doppler velocity in granules.The distributions of longitudinal and transverse apparent magnetic flux densities, Doppler velocity and continuum intensity of granules are obtained, and their unsigned magnetic flux measured. Two approaches are carried out in this study. First we obtained the magnetic properties of granulation by averaging the measurements for all the sampling granules. Secondly, we reconstructed an average granular cell based on a sub-sample, and obtained the detailed distribution of apparent magnetic flux density within the model granular cell. All the results have been compared with that of inter-granular lanes and a few typical abnormal granules.Our statistic analysis reveals the following results: (1) The unsigned magnetic flux of individual granule spans the range from 1.1 × 10 15 Mx to 3.3 × 10 18 Mx with a peak distribution at 1.6×10 16 Mx; (2) The unsigned longitudinal apparent flux density of granules ranges from almost zero to 212 Mx cm −2 with a mean longitudinal apparent flux density of 12 Mx cm −2 , while the transverse apparent flux density of granules ranges from 4 to 218 Mx cm −2 with a mean transverse apparent flux density of 79 Mx cm −2 . The longitudinal and transverse apparent magnetic flux densities of granules are positively correlated, and the longitudinal apparent flux density of granules is weaker than the corresponding transverse apparent flux density; (3) The magnetic inclination of granules with respect to the surface that's perpendicular to the line-of-sight falls in the range of 4.8 to 76.7

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A morphological study of the solar granulation

Cited by 40 publications

References 5 publications

Thermal Fine Structure and Magnetic Fields in the Solar Atmosphere: Spicules and Fibrils

Thermal Fine Structure and Magnetic Fields in the Solar Atmosphere: Spicules and Fibrils

MHD turbulence and heating of the open field-line solar corona

Vector Magnetic Fields of Solar Granulation

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