IRIS Mg ii Observations and Non-LTE Modeling of Off-limb Spicules in a Solar Polar Coronal Hole

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F20%3A00534671" target="_blank" >RIV/67985815:_____/20:00534671 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.3847/1538-4357/ab5db1" target="_blank" >https://doi.org/10.3847/1538-4357/ab5db1</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/ab5db1" target="_blank" >10.3847/1538-4357/ab5db1</a>

Jazyk výsledku

angličtina

Název v původním jazyce

IRIS Mg ii Observations and Non-LTE Modeling of Off-limb Spicules in a Solar Polar Coronal Hole

Popis výsledku v původním jazyce

We investigated the off-limb spicules observed in the Mg ii h and k lines by IRIS in a solar polar coronal hole. We analyzed the large data set of obtained spectra to extract quantitative information about the line intensities, shifts, and widths. The observed Mg ii line profiles are broad and double peaked at lower altitudes, broad but flat topped at middle altitudes, and narrow and single peaked with the largest Doppler shifts at higher altitudes. We use one-dimensional non-LTE vertical slab models (i.e., models that consider departures from local thermodynamic equilibrium) in single-slab and multi-slab configurations to interpret the observations and to investigate how a superposition of spicules along the line of sight (LOS) affects the synthetic Mg ii line profiles. The used multi-slab models either are static, i.e., without any LOS velocities, or assume randomly assigned LOS velocities of individual slabs, representing the spicule dynamics. We conducted such single-slab and multi-slab modeling for a broad set of model input parameters and showed the dependence of the Mg ii line profiles on these parameters. We demonstrated that the observed line widths of the h and k line profiles are strongly affected by the presence of multiple spicules along the LOS. We later showed that the profiles obtained at higher altitudes can be reproduced by single-slab models representing individual spicules. We found that the multi-slab model with a random distribution of the LOS velocities ranging from -25 to 25 km s(-1) can well reproduce the width and the shape of Mg ii profiles observed at middle altitudes.

Název v anglickém jazyce

IRIS Mg ii Observations and Non-LTE Modeling of Off-limb Spicules in a Solar Polar Coronal Hole

Popis výsledku anglicky

We investigated the off-limb spicules observed in the Mg ii h and k lines by IRIS in a solar polar coronal hole. We analyzed the large data set of obtained spectra to extract quantitative information about the line intensities, shifts, and widths. The observed Mg ii line profiles are broad and double peaked at lower altitudes, broad but flat topped at middle altitudes, and narrow and single peaked with the largest Doppler shifts at higher altitudes. We use one-dimensional non-LTE vertical slab models (i.e., models that consider departures from local thermodynamic equilibrium) in single-slab and multi-slab configurations to interpret the observations and to investigate how a superposition of spicules along the line of sight (LOS) affects the synthetic Mg ii line profiles. The used multi-slab models either are static, i.e., without any LOS velocities, or assume randomly assigned LOS velocities of individual slabs, representing the spicule dynamics. We conducted such single-slab and multi-slab modeling for a broad set of model input parameters and showed the dependence of the Mg ii line profiles on these parameters. We demonstrated that the observed line widths of the h and k line profiles are strongly affected by the presence of multiple spicules along the LOS. We later showed that the profiles obtained at higher altitudes can be reproduced by single-slab models representing individual spicules. We found that the multi-slab model with a random distribution of the LOS velocities ranging from -25 to 25 km s(-1) can well reproduce the width and the shape of Mg ii profiles observed at middle altitudes.

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

2020

Kód důvěrnosti údajů

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

Název periodika

Astrophysical Journal

ISSN

1538-4357

e-ISSN

—

Svazek periodika

888

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

17

Strana od-do

42

Kód UT WoS článku

000507612800001

EID výsledku v databázi Scopus

2-s2.0-85080953903