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Homologous flares and magnetic field topology in active region NOAA 10501 on 20 November 2003
(Springer, 2011-03)
We present and interpret observations of two morphologically homologous flares
that occurred in active region (AR) NOAA 10501 on 20 November 2003. Both flares displayed four homologous Hα ribbons and were both accompanied ...
Active-region Tilt Angles from White-light Images and Magnetograms: The Role of Magnetic Tongues
(IOP Publishing, 2020-05)
The presence of elongations in active region (AR) polarities, called magnetic tongues, are mostly visible during their emergence phase. AR tilts have been measured thoroughly using long-term white-light (WL) databases, ...
How Can a Negative Magnetic Helicity Active Region Generate a Positive Helicity Magnetic Cloud?
(Springer, 2009-11-13)
The geoeffective magnetic cloud (MC) of 20 November 2003 was associated with the 18 November 2003 solar active events in previous studies. In some of these, it was estimated that the magnetic helicity carried by the MC had ...
Active-region twist derived from magnetic tongues and linear force-free extrapolations
(Springer, 2015-12)
The main aim of this study is to compare the amount of twist present in emerging active regions (ARs) from photospheric and coronal data. We use linear force-free field models of the observed coronal structure of ARs to ...
Correcting the effect of magnetic tongues on the tilt angle of bipolar active regions
(EDP Sciences, 2019-12)
Context. The magnetic polarities of bipolar active regions (ARs) exhibit elongations in line-of-sight magnetograms during their emergence. These elongations are referred to as magnetic tongues and attributed to the presence ...
Magnetic pileup boundary and field draping at Comet Halley
(Elsevier, 2014-06)
The approach of the Rosetta S/C to Comet Churyumov-Gerasimenko in 2014 reactivates the interest in the plasma interaction of the solar wind with the cometary coma. In preparation for the upcoming S/C observations and the ...
Properties of Magnetic tongues over a Solar Cycle
(Springer, 2016-05)
The photospheric spatial distribution of the main magnetic polarities of bipolar
active regions (ARs) present during their emergence deformations are known as magnetic tongues. They are attributed to the presence of twist ...
Magnetic Topology of Active Regions and Coronal Holes: Implications for Coronal Outflows and the Solar Wind
(Springer, 2012-11)
During 2-18 January 2008 a pair of low-latitude opposite-polarity coronal holes (CHs) were observed on the Sun with two active regions (ARs) and the heliospheric plasma sheet located between them. We use the Hinode/EUV ...
Twisted Flux Tube Emergence Evidenced in Longitudinal Magnetograms: Magnetic Tongues
(Springer, 2011-05)
Bipolar active regions (ARs) are thought to be formed by twisted flux tubes, as the presence of such twist is theoretically required for a cohesive rise through the whole convective zone. We use longitudinal magnetograms ...
Magnetic Flux and Helicity of Magnetic Clouds
(Springer, 2016-01)
Magnetic clouds (MCs) are formed by flux ropes (FRs) launched from the Sun as part of coronal mass ejections (CMEs). They carry away a large amount of magnetic flux and helicity. The main aim of this study is to quantify ...