Relative alpha in the magnetohydrodynamics with open magnetic field boundary and its application to the solar eruption

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00617427" target="_blank" >RIV/67985815:_____/25:00617427 - isvavai.cz</a>

Výsledek na webu

<a href="https://hdl.handle.net/11104/0365434" target="_blank" >https://hdl.handle.net/11104/0365434</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/ada278" target="_blank" >10.3847/1538-4357/ada278</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Relative alpha in the magnetohydrodynamics with open magnetic field boundary and its application to the solar eruption

Popis výsledku v původním jazyce

An instability criterion in the magnetohydrodynamics (MHD) with the open boundary of a magnetic field is proposed in this paper. We use a series of linear force-free extrapolation fields, in which the normal part of the magnetic field is fixed, to obtain the linear fitting coefficient called relative alpha by using the cojoined value of magnetic free energy and magnetic flux at the open boundary (Ef Phi 2) and the square of relative magnetic helicity ( HR2 ). We calculate this coefficient of the magnetic field above active regions NOAA 8210 and NOAA 11429 obtained by the photospheric-data-driven MHD model. It is found that the fitting coefficient is a good proxy of the criterion to indicate the occurrence of instability after which the magnetic reconnection happens and causes the fast release of magnetic energy. We also applied this method to the continuous evolution of the three-dimensional magnetic field of NOAA 11158 based on the measurement of the photospheric vector magnetic field of Solar Dynamics Observatory/Helioseismic and Magnetic Imager by the nonlinear force-free extrapolation method. The calculated coefficient when the major flare happened based on the extrapolation data is very close to the expected ones, which perfectly reflects the occurrence of instability, and the difference is even less than 7%. This relative alpha is very helpful to evaluate how far it is from the instability in the MHD and quantitatively estimate the occurrence of solar eruption in the space weather forecast.

Název v anglickém jazyce

Relative alpha in the magnetohydrodynamics with open magnetic field boundary and its application to the solar eruption

Popis výsledku anglicky

An instability criterion in the magnetohydrodynamics (MHD) with the open boundary of a magnetic field is proposed in this paper. We use a series of linear force-free extrapolation fields, in which the normal part of the magnetic field is fixed, to obtain the linear fitting coefficient called relative alpha by using the cojoined value of magnetic free energy and magnetic flux at the open boundary (Ef Phi 2) and the square of relative magnetic helicity ( HR2 ). We calculate this coefficient of the magnetic field above active regions NOAA 8210 and NOAA 11429 obtained by the photospheric-data-driven MHD model. It is found that the fitting coefficient is a good proxy of the criterion to indicate the occurrence of instability after which the magnetic reconnection happens and causes the fast release of magnetic energy. We also applied this method to the continuous evolution of the three-dimensional magnetic field of NOAA 11158 based on the measurement of the photospheric vector magnetic field of Solar Dynamics Observatory/Helioseismic and Magnetic Imager by the nonlinear force-free extrapolation method. The calculated coefficient when the major flare happened based on the extrapolation data is very close to the expected ones, which perfectly reflects the occurrence of instability, and the difference is even less than 7%. This relative alpha is very helpful to evaluate how far it is from the instability in the MHD and quantitatively estimate the occurrence of solar eruption in the space weather forecast.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

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

Název periodika

Astrophysical Journal

ISSN

0004-637X

e-ISSN

1538-4357

Svazek periodika

980

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

5

Strana od-do

206

Kód UT WoS článku

001421901500001

EID výsledku v databázi Scopus

2-s2.0-85218236695