Density-dependent ionization equilibria for carbon with kappa distributions

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F24%3A00601308" target="_blank" >RIV/67985815:_____/24:00601308 - isvavai.cz</a>

Výsledek na webu

<a href="https://hdl.handle.net/11104/0358577" target="_blank" >https://hdl.handle.net/11104/0358577</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202451375" target="_blank" >10.1051/0004-6361/202451375</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Density-dependent ionization equilibria for carbon with kappa distributions

Popis výsledku v původním jazyce

Context. Recent atomic models for the solar transition region have shown the importance of electron density, photoionization, and charge transfer on the ionization equilibria and line intensities of several elements and ions, especially from the Li- and Na-like ion sequences. Aims. Non-Maxwellian electron distributions have been proposed as one solution that may account for the discrepancies. We have studied the interplay of the new atomic models with the effects of energetic particles, which have been shown to alter ionization equilibria considerably. Methods. Level-resolved ionization and recombination rates were calculated for non-Maxwellian kappa distributions and included in a collisional-radiative model for carbon. The effect of photoionization and density suppression of dielectronic recombination for kappa distributions were also included in the models, and the models were run at a variety of densities and pressures. Results. We find that the level-resolved collisional ionization rates increase with electron density, while the radiative and dielectronic recombination rates decrease. Their overall effect on the ionization equilibrium is to shift the formation of the lower charge states to a lower temperature and increase their peak abundance, especially for C IV. These shifts are not as significant as the effects of the non-extensive shape parameter given by the thermodynamic kappa index, kappa. With decreasing kappa, that is, with increasing departure from a Maxwellian distribution, ion formation moves to a much lower temperature, ion formation takes place over a wider temperature range, and peak abundances decrease. The effect of level-resolved rates and density suppression on the ion balances diminishes as kappa decreases. Photoionization is shown to be significant only at relatively low densities and high kappa. Conclusions. Density effects are an important factor to consider in higher-density plasma and improve on the coronal approximation, even where there are significant departures from Maxwellian energy distributions. However, the changes they make to ion formation are not as significant as when there are electron distributions with very low kappa-values.

Název v anglickém jazyce

Density-dependent ionization equilibria for carbon with kappa distributions

Popis výsledku anglicky

Context. Recent atomic models for the solar transition region have shown the importance of electron density, photoionization, and charge transfer on the ionization equilibria and line intensities of several elements and ions, especially from the Li- and Na-like ion sequences. Aims. Non-Maxwellian electron distributions have been proposed as one solution that may account for the discrepancies. We have studied the interplay of the new atomic models with the effects of energetic particles, which have been shown to alter ionization equilibria considerably. Methods. Level-resolved ionization and recombination rates were calculated for non-Maxwellian kappa distributions and included in a collisional-radiative model for carbon. The effect of photoionization and density suppression of dielectronic recombination for kappa distributions were also included in the models, and the models were run at a variety of densities and pressures. Results. We find that the level-resolved collisional ionization rates increase with electron density, while the radiative and dielectronic recombination rates decrease. Their overall effect on the ionization equilibrium is to shift the formation of the lower charge states to a lower temperature and increase their peak abundance, especially for C IV. These shifts are not as significant as the effects of the non-extensive shape parameter given by the thermodynamic kappa index, kappa. With decreasing kappa, that is, with increasing departure from a Maxwellian distribution, ion formation moves to a much lower temperature, ion formation takes place over a wider temperature range, and peak abundances decrease. The effect of level-resolved rates and density suppression on the ion balances diminishes as kappa decreases. Photoionization is shown to be significant only at relatively low densities and high kappa. Conclusions. Density effects are an important factor to consider in higher-density plasma and improve on the coronal approximation, even where there are significant departures from Maxwellian energy distributions. However, the changes they make to ion formation are not as significant as when there are electron distributions with very low kappa-values.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/GA22-07155S" target="_blank" >GA22-07155S: Modelování a pozorovatelné projevy nerovnovážných procesů ve slunečním spektru</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

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

690

Číslo periodika v rámci svazku

Oct.

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

13

Strana od-do

A340

Kód UT WoS článku

001352465500002

EID výsledku v databázi Scopus

2-s2.0-85208681619