Novel framework for the three-dimensional NLTE inverse problem

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F22%3A00556497" target="_blank" >RIV/67985815:_____/22:00556497 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1051/0004-6361/202142079" target="_blank" >https://doi.org/10.1051/0004-6361/202142079</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202142079" target="_blank" >10.1051/0004-6361/202142079</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Novel framework for the three-dimensional NLTE inverse problem

Popis výsledku v původním jazyce

The inversion of spectropolarimetric observations of the solar upper atmosphere is one of the most challenging goals in solar physics. If we account for all relevant ingredients of the spectral line formation process, such as the three-dimensional (3D) radiative transfer out of local thermodynamic equilibrium (NLTE), the task becomes extremely computationally expensive. Instead of generalizing 1D methods to 3D, we have developed a new approach to the inverse problem. In our meshfree method, we do not consider the requirement of 3D NLTE consistency as an obstacle, but as a natural regularization with respect to the traditional pixel-by-pixel methods. This leads to more robust and less ambiguous solutions. We solve the 3D NLTE inverse problem as an unconstrained global minimization problem that avoids repetitive evaluations of the ? operator. Apart from the 3D NLTE consistency, the method allows us to easily include additional conditions of physical consistency such as the zero divergence of the magnetic field. Stochastic ingredients make the method less prone to ending up within the local minima of the loss function. Our method is capable of solving the inverse problem faster by several orders of magnitude than by using grid-based methods. The method can provide accurate and physically consistent results if sufficient computing time is available, along with approximate solutions in the case of very complex plasma structures or limited computing time.

Název v anglickém jazyce

Novel framework for the three-dimensional NLTE inverse problem

Popis výsledku anglicky

The inversion of spectropolarimetric observations of the solar upper atmosphere is one of the most challenging goals in solar physics. If we account for all relevant ingredients of the spectral line formation process, such as the three-dimensional (3D) radiative transfer out of local thermodynamic equilibrium (NLTE), the task becomes extremely computationally expensive. Instead of generalizing 1D methods to 3D, we have developed a new approach to the inverse problem. In our meshfree method, we do not consider the requirement of 3D NLTE consistency as an obstacle, but as a natural regularization with respect to the traditional pixel-by-pixel methods. This leads to more robust and less ambiguous solutions. We solve the 3D NLTE inverse problem as an unconstrained global minimization problem that avoids repetitive evaluations of the ? operator. Apart from the 3D NLTE consistency, the method allows us to easily include additional conditions of physical consistency such as the zero divergence of the magnetic field. Stochastic ingredients make the method less prone to ending up within the local minima of the loss function. Our method is capable of solving the inverse problem faster by several orders of magnitude than by using grid-based methods. The method can provide accurate and physically consistent results if sufficient computing time is available, along with approximate solutions in the case of very complex plasma structures or limited computing time.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

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

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

Kód důvěrnosti údajů

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

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

659

Číslo periodika v rámci svazku

March

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

18

Strana od-do

A137

Kód UT WoS článku

000770104200001

EID výsledku v databázi Scopus

2-s2.0-85127135134