A distinct magnetic property of the inner penumbral boundary Formation of a stable umbra-penumbra boundary in a sunspot

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F15%3A00449432" target="_blank" >RIV/67985815:_____/15:00449432 - isvavai.cz</a>

Výsledek na webu

<a href="http://hdl.handle.net/11104/0250984" target="_blank" >http://hdl.handle.net/11104/0250984</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/201425501" target="_blank" >10.1051/0004-6361/201425501</a>

Jazyk výsledku

angličtina

Název v původním jazyce

A distinct magnetic property of the inner penumbral boundary Formation of a stable umbra-penumbra boundary in a sunspot

Popis výsledku v původním jazyce

We study the evolving penumbra and the related changing value of the vertical component of the magnetic field (B-ver) on the boundary between umbra and penumbra using unique observations taken with GFPI/VTT. For comparison with stable sunspots, we also analyse the two maps observed by Hinode/SP on the same spot after the penumbra formed. The vertical component of the magnetic field, B-ver, at the umbra-penumbra boundary increases during penumbra formation owing to the incursion of the penumbra into umbral areas. After 2.5 h, the penumbra reaches a stable state as shown by the GFPI data. At this stable stage, the simultaneous Hinode/SP observations show a B-ver value comparable to that of umbra-penumbra boundaries of fully fledged sunspots (B-ver-stable). We confirm that the umbra-penumbra boundary, traditionally defined by an intensity threshold, is also characterised by a distinct canonical magnetic property, namely by B-ver-stable. During the penumbra formation process, the inner penumbra extends into regions where the umbra previously prevailed. Hence, in areas where B-ver is smaller than B-ver-stable, the magneto-convection mode operating in the umbra turns into a penumbral mode.

Název v anglickém jazyce

A distinct magnetic property of the inner penumbral boundary Formation of a stable umbra-penumbra boundary in a sunspot

Popis výsledku anglicky

We study the evolving penumbra and the related changing value of the vertical component of the magnetic field (B-ver) on the boundary between umbra and penumbra using unique observations taken with GFPI/VTT. For comparison with stable sunspots, we also analyse the two maps observed by Hinode/SP on the same spot after the penumbra formed. The vertical component of the magnetic field, B-ver, at the umbra-penumbra boundary increases during penumbra formation owing to the incursion of the penumbra into umbral areas. After 2.5 h, the penumbra reaches a stable state as shown by the GFPI data. At this stable stage, the simultaneous Hinode/SP observations show a B-ver value comparable to that of umbra-penumbra boundaries of fully fledged sunspots (B-ver-stable). We confirm that the umbra-penumbra boundary, traditionally defined by an intensity threshold, is also characterised by a distinct canonical magnetic property, namely by B-ver-stable. During the penumbra formation process, the inner penumbra extends into regions where the umbra previously prevailed. Hence, in areas where B-ver is smaller than B-ver-stable, the magneto-convection mode operating in the umbra turns into a penumbral mode.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2015

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

1432-0746

e-ISSN

—

Svazek periodika

580

Číslo periodika v rámci svazku

August

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

4

Strana od-do

"L1/1"-"L1/4"

Kód UT WoS článku

000360020200146

EID výsledku v databázi Scopus

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