Observations of solar small-scale magnetic flux-sheet emergence

Aims. Moreno-Insertis et al. (2018) recently discovered two types of flux emergence in their numerical simulations: magnetic loops and magnetic sheet emergence. Whereas magnetic loop emergence has been documented well in the last years, by utilising high-resolution full Stokes data from ground-based telescopes as well as satellites, magnetic sheet emergence is still an understudied process. We report here on the first clear observational evidence of a magnetic sheet emergence and characterise its development. Methods. Full Stokes spectra from the Hinode spectropolarimeter were inverted with the SIR code to obtain solar atmospheric parameters such as temperature, line-of-sight velocities and full magnetic field vector information. Results. We analyse a magnetic flux emergence event observed in the quiet-sun internetwork. After a large scale appearance of linear polarisation, a magnetic sheet with horizontal magnetic flux density of up to 194 Mx/cm$^{2}$ hovers in the low photosphere spanning a region of 2 to 3 arcsec. The magnetic field azimuth obtained through Stokes inversions clearly shows an organised structure of transversal magnetic flux density emerging. The granule below the magnetic flux-sheet tears the structure apart leaving the emerged flux to form several magnetic loops at the edges of the granule. Conclusions. A large amount of flux with strong horizontal magnetic fields surfaces through the interplay of buried magnetic flux and convective motions. The magnetic flux emerges within 10 minutes and we find a longitudinal magnetic flux at the foot points of the order of $\sim$$10^{18}$ Mx. This is one to two orders of magnitude larger than what has been reported for small-scale magnetic loops. The convective flows feed the newly emerged flux into the pre-existing magnetic population on a granular scale.Comment: 6 pages, 5 figures, accepted as a letter in A&

Moving magnetic features around a pore

A. J. Kaithakkal et. al.©2017 The American Astronomical Society. All rights reserved.Spectropolarimetric observations from Sunrise/IMaX, obtained in 2013 June, are used for a statistical analysis to determine the physical properties of moving magnetic features (MMFs) observed near a pore. MMFs of the same and opposite polarity, with respect to the pore, are found to stream from its border at an average speed of 1.3 km s−1 and 1.2 km s−1, respectively, with mainly same-polarity MMFs found further away from the pore. MMFs of both polarities are found to harbor rather weak, inclined magnetic fields. Opposite-polarity MMFs are blueshifted, whereas same-polarity MMFs do not show any preference for up- or downflows. Most of the MMFs are found to be of sub-arcsecond size and carry a mean flux of ~1.2 × 1017 Mx.The German contribution to Sunrise and its reflight was funded by the Max Planck Foundation, the Strategic Innovations Fund of the President of the Max Planck Society (MPG), DLR, and private donations by supporting members of the Max Planck Society, which is gratefully acknowledged. The Spanish contribution was funded by the Ministerio de Economía y Competitividad under Projects ESP2013-47349-C6 and ESP2014-56169-C6, partially using European FEDER funds. The HAO contribution was partly funded through NASA grant number NNX13AE95G. This work was partly supported by the BK21 plus program through the National Research Foundation (NRF) funded by the Ministry of Education of Korea.Peer reviewe

A reconnection driven magnetic flux cancellation and a quiet Sun Ellerman bomb

The focus of this investigation is to quantify the conversion of magnetic to thermal energy initiated by a quiet Sun cancellation event and to explore the resulting dynamics from the interaction of the opposite polarity magnetic features. We used imaging spectroscopy in the H$\alpha$ line, along with spectropolarimetry in the \ion{Fe}{I} 6173~{\AA} and \ion{Ca}{II} 8542~{\AA} lines from the Swedish Solar Telescope (SST) to study a reconnection-related cancellation and the appearance of a quiet Sun Ellerman bomb (QSEB). We observed, for the first time, QSEB signature in both the wings and core of the \ion{Fe}{I} 6173~{\AA} line. We also found that, at times, the \ion{Fe}{I} line-core intensity reaches higher values than the quiet Sun continuum intensity. From FIRTEZ-dz inversions of the Stokes profiles in \ion{Fe}{I} and \ion{Ca}{II} lines, we found enhanced temperature, with respect to the quiet Sun values, at the photospheric ($\log\tau_c$ = -1.5; $\sim$1000 K) and lower chromospheric heights ($\log\tau_c$ = -4.5; $\sim$360 K). From the calculation of total magnetic energy and thermal energy within these two layers it was confirmed that the magnetic energy released during the flux cancellation can support heating in the aforesaid height range. Further, the temperature stratification maps enabled us to identify cumulative effects of successive reconnection on temperature pattern, including recurring temperature enhancements. Similarly, Doppler velocity stratification maps revealed impacts on plasma flow pattern, such as a sudden change in the flow direction.Comment: 16 pages, 12 figures, accepted for publication in MNRA

緑茶中のビタミンB12濃度に与えるアスコルビン酸の影響

急須を用いて乾燥茶葉から抽出された緑茶抽出液中のビタミンB_濃度は849±35pg/100ml,缶入りおよびペットボトル入り緑茶飲料5種の平均濃度は280±45pg/100mlであり,急須で入れた場合の方が3倍高い結果となった。ビタミンB_が後者で低かった理由として製造工程中にアスコルビン酸が添加されたためである可能性が考えられる。アスコルビン酸はビタミンB_と共存する場合にビタミンB_を分解することが既に報告されている。そこでアスコルビン酸を測定したところ,急須による緑茶抽出液5.87±0.66m/100ml,缶入りおよびペットボトル入り緑茶飲料5種の平均濃度は35.22±8.27mg/100mlであり,後者が前者の6倍の値であった。アスコルビン酸の添加によってビタミンB_濃度が影響を受けるのかを検討するために,急須を用いた抽出の際にアスコルビン酸を添加し,ビタミンB_濃度への影響を確認した。しかし,その影響は,緑茶抽出液のビタミンB_濃度の7%の減少に留まっていた(緑茶飲料では67%減少していた)。さらにアスコルビン酸添加後の加圧加熱(120℃)の影響も調べたが,影響は見られなかった。これらの結果から,極めて微量ながらも緑茶からビタミンB_が摂取できる可能性が示され,それは緑茶飲料より急須で乾燥茶葉から抽出した場合の方がより効率がよいことが示された。The vitamin B_ concentration in the green tea extract poured out from the teapot was measured to be 849±35 pg/100ml. The average concentration of 5 different green tea beverages from the markets was 280±45 pg/100ml. The lower content of vitamin B_ in the tea beverages may be due to the supplemented ascorbic acid added in the process of manufacture since the content of vitamin B_ in the solution was reported to decrease in coexistence with ascorbic acid. In fact the concentration of ascorbic acid in the tea beverages, 35.22±8.27mg/100ml in average, was six times higher than that of the poured tea, 5.87±0.66mg/100ml. Then we examined the effect of ascorbic acid added during the tea extraction on the vitamin B_ concentration. However, the addition of ascorbic acid at the same concentration of the tea beverages decreased only 7% of the vitamin B_ concentration in the poured tea compared to 67% decrease observed in the tea beverages. Moreover, the effect of heating at 120°C under pressure after the addition of ascorbic acid was examined and no difference was observed by heating. The result indicated that the green tea poured out from the teapot, though in a small quantity, was a better source for vitamin B_ than the tea beverages on markets

Moving Magnetic Features around a Pore

Spectropolarimetric observations from Sunrise II/IMaX obtained in June 2013 are used for a statistical analysis to determine the physical properties of moving magnetic features (MMFs) observed near a pore. MMFs of the same and opposite polarity with respect to the pore are found to stream from its border at an average speed of 1.3 km s$^{-1}$ and 1.2 km s$^{-1}$ respectively, with mainly same-polarity MMFs found further away from the pore. MMFs of both polarities are found to harbor rather weak, inclined magnetic fields. Opposite-polarity MMFs are blue-shifted, while same-polarity MMFs do not show any preference for up- or downflows. Most of the MMFs are found to be of sub-arcsecond size and carry a mean flux of $\sim$ 1.2$\times 10^{17}$ Mx.Comment: 8 pages, 4 figures, accepted for publication in ApJ