Results 1 to 10 of about 423,592 (152)
Astrophysical JournalWe explore what fraction of delta sunspots with a sharp polarity inversion line (PIL) in photospheric magnetograms are produced by a writhe kink in an emerging twisted flux rope.
Sanjiv Tiwari +2 more
exaly +4 more sources
Interactions between nested sunspots. 1: The formation and breakup of a delta-type sunspot [PDF]
Astrophysical Journal, 1994 We investigate a nest of sunspots in which three ordinary bipolar pairs of sunspots are aligned collinearly. The usual spreading action of the growing regions brings two spots of leading polarity together (p-p collision) and forces the leading and trailing spots of the two interior regions to overlap inot a single penumbra (p-f collision), thus forming
V Gaizauskas
exaly +4 more sources
A Statistical Study of $\delta $-Sunspots from Solar Cycle 23 to 25
Solar PhysicsAccepted for publication in Solar Physics, 23 pages, 9 figures, 1 appendix ...
exaly +3 more sources
Journal of Water and Climate Change, 2022 Understanding the spatiotemporal pattern of precipitation concentration is important in the water cycle under changing environments. In this study, the daily precipitation concentration index in the Yangtze River Delta in China is calculated based on the
Chao Mei +6 more
doaj +1 more source
The configuration and failed eruption of a complex magnetic flux rope above aδsunspot region [PDF]
Astronomy & Astrophysics, 2021 Aims.We aim to investigate the configuration of a complex flux rope above theδsunspot region in the National Oceanic and Atmospheric Administration AR 11515 and its eruptive expansion during a confined M5.3-class flare.Methods.We studied the formation of theδsunspot using the continuum intensity images and photospheric vector magnetograms provided by ...
Lijuan Liu +6 more
openaire +2 more sources
The Astrophysical Journal Letters, 2023 We measure current helicity ( H _r ^c ) as well as proxies for twist ( α _r ) and writhe ( W ) in the isolated magnetic knots of three delta ( δ )-sunspots and report that the observations are consistent with a kink instability acting on a highly twisted
Peter J. Levens +4 more
doaj +1 more source
Automatic Detection of Magnetic δ $\delta$ in Sunspot Groups [PDF]
Solar Physics, 2015 14 pages, 5 figures, accepted for publication in ...
Padinhatteeri, Sreejith +3 more
openaire +2 more sources
Formation of superstrong horizontal magnetic field in delta-type sunspot in radiation magnetohydrodynamic simulations [PDF]
Monthly Notices of the Royal Astronomical Society, 2020 ABSTRACT We perform a series of radiative magnetohydrodynamic simulations to understand the amplification mechanism of the exceptionally strong horizontal magnetic field in delta-type sunspots. In the simulations, we succeed in reproducing the delta-type sunspot and resulting strong magnetic field exceeding 6000 G in a light bridge ...
H Hotta, S Toriumi
openaire +2 more sources
Large Photospheric Doppler Shift in Solar Active Region 12673. I. Field-aligned Flows
The Astrophysical Journal, 2023 Delta ( δ ) sunspots sometimes host fast photospheric flows along the central magnetic polarity inversion line (PIL). Here we study the strong Doppler shift signature in the central penumbral light bridge of solar active region NOAA 12673.
Jiayi Liu +5 more
doaj +1 more source
Evolution and Flare Activity of δ $\delta$ -Sunspots in Cycle 23 [PDF]
Solar Physics, 2015 The emergence and magnetic evolution of solar active regions (ARs) of beta-gamma-delta type, which are known to be highly flare-productive, were studied with the SOHO/MDI data in Cycle 23. We selected 31 ARs that can be observed from their birth phase, as unbiased samples for our study.
Takizawa, Kan, Kitai, Reizaburo
openaire +2 more sources