Characterization of Magnetic Flux in the Quiet Sun

2002 ◽  
Vol 573 (1) ◽  
pp. 431-444 ◽  
Author(s):  
B. W. Lites
Keyword(s):  
2020 ◽  
Vol 634 ◽  
pp. A131
Author(s):  
A. J. Kaithakkal ◽  
J. M. Borrero ◽  
C. E. Fischer ◽  
C. Dominguez-Tagle ◽  
M. Collados

A quiet Sun magnetic flux cancellation event at the disk center was recorded using the Integral Field Unit (IFU) mounted on the GREGOR Infrared Spectrograph (GRIS). The GRIS instrument sampled the event in the photospheric Si I 10827 Å spectral line. The cancellation was preceded by a significant rise in line core intensity and excitation temperature, which is inferred from Stokes inversions under local thermodynamic equilibrium (LTE). The opposite polarity features seem to undergo reconnection above the photosphere. We also found that the border pixels neighboring the polarity inversion line of one of the polarities exhibit a systematic variation of area asymmetry. Area asymmetry peaks right after the line core intensity enhancement and gradually declines thereafter. Analyzing Stokes profiles recorded from either side of the polarity inversion line could therefore potentially provide additional information on the reconnection process related to magnetic flux cancellation. Further analysis without assuming LTE will be required to fully characterize this event.


2020 ◽  
Vol 633 ◽  
pp. A67 ◽  
Author(s):  
I. Kontogiannis ◽  
G. Tsiropoula ◽  
K. Tziotziou ◽  
C. Gontikakis ◽  
C. Kuckein ◽  
...  

Context. We study the evolution of a small-scale emerging flux region (EFR) in the quiet Sun, from its emergence in the photosphere to its appearance in the corona and its decay. Aims. We track processes and phenomena that take place across all atmospheric layers; we explore their interrelations and compare our findings with those from recent numerical modelling studies. Methods. We used imaging as well as spectral and spectropolarimetric observations from a suite of space-borne and ground-based instruments. Results. The EFR appears in the quiet Sun next to the chromospheric network and shows all morphological characteristics predicted by numerical simulations. The total magnetic flux of the region exhibits distinct evolutionary phases, namely an initial subtle increase, a fast increase with a Co-temporal fast expansion of the region area, a more gradual increase, and a slow decay. During the initial stages, fine-scale G-band and Ca II H bright points coalesce, forming clusters of positive- and negative-polarity in a largely bipolar configuration. During the fast expansion, flux tubes make their way to the chromosphere, pushing aside the ambient magnetic field and producing pressure-driven absorption fronts that are visible as blueshifted chromospheric features. The connectivity of the quiet-Sun network gradually changes and part of the existing network forms new connections with the newly emerged bipole. A few minutes after the bipole has reached its maximum magnetic flux, the bipole brightens in soft X-rays forming a coronal bright point. The coronal emission exhibits episodic brightenings on top of a long smooth increase. These coronal brightenings are also associated with surge-like chromospheric features visible in Hα, which can be attributed to reconnection with adjacent small-scale magnetic fields and the ambient quiet-Sun magnetic field. Conclusions. The emergence of magnetic flux even at the smallest scales can be the driver of a series of energetic phenomena visible at various atmospheric heights and temperature regimes. Multi-wavelength observations reveal a wealth of mechanisms which produce diverse observable effects during the different evolutionary stages of these small-scale structures.


2008 ◽  
Vol 672 (2) ◽  
pp. 1237-1253 ◽  
Author(s):  
B. W. Lites ◽  
M. Kubo ◽  
H. Socas‐Navarro ◽  
T. Berger ◽  
Z. Frank ◽  
...  
Keyword(s):  

2019 ◽  
Vol 55 (5) ◽  
pp. 1-10 ◽  
Author(s):  
V. Suresh ◽  
A. Abudhahir ◽  
Jackson Daniel

Solar Physics ◽  
1982 ◽  
Vol 80 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Barry J. Labonte ◽  
Robert Howard
Keyword(s):  

2017 ◽  
Vol 229 (1) ◽  
pp. 17 ◽  
Author(s):  
H. N. Smitha ◽  
L. S. Anusha ◽  
S. K. Solanki ◽  
T. L. Riethmüller

Author(s):  
Vanessa Co ◽  
Scott Ironside ◽  
Chuck Ellis ◽  
Garrett Wilkie

Management of mechanical damage is an issue that many pipeline operators are facing. This paper presents a method to characterize dents based on the analysis of the BJ Vectra Magnetic Flux Leakage (MFL) tool signals. This is an approach that predicts the severity of mechanical damage by identifying the presence of some key elements such as gouging, cracking, and metal loss within dents as well as multiple dents and wrinkles. Enbridge Pipelines Inc. worked with BJ Services to enhance the knowledge that can be gained from MFL tool signals by defining tool signal subtleties in dents. This additional characterization provides information about the existence of gouging, metal loss, and cracking. This has been accomplished through detailed studies of the ILI data and follow-up field investigations, which validate the predictions. One of the key learnings has been that the radial and circumferential components of the MFL Vectra tool are highly important in the characterization and classification of mechanical damage. Non-destructive examination has verified that predictions in detecting the presence of gouging and cracking (and other defects within dents based on tool signals) have been accurate.


1990 ◽  
Vol 138 ◽  
pp. 185-188
Author(s):  
Wolfgang Kalkofen

The solar chromosphere is identified with the atmosphere inside magnetic flux tubes. In the quiet sun, the layers of the low and middle chromosphere are heated by compressive waves with periods mainly between 2 min and 4 min. These long-period waves probably supply all the energy required for the heating of the quiet solar chromosphere.


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