Non-equilibrium ionization by a periodic electron beam II. Synthetic Si IV and O IV transition region spectra

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F18%3A00494687" target="_blank" >RIV/67985815:_____/18:00494687 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1051/0004-6361/201731744" target="_blank" >http://dx.doi.org/10.1051/0004-6361/201731744</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/201731744" target="_blank" >10.1051/0004-6361/201731744</a>

Result language

angličtina

Original language name

Non-equilibrium ionization by a periodic electron beam II. Synthetic Si IV and O IV transition region spectra

Original language description

To investigate the combination of non-equilibrium ionization and high-energy particles, we apply the model of the periodic electron beam, represented by a kappa-distribution that recurs at periods of several seconds, to plasma at chromospheric temperatures of 10(4) K. This simple model can approximate a burst of energy release involving accelerated particles. Instantaneous time-dependent charge states of silicon and oxygen were calculated and used to synthesize the instantaneous and period-averaged spectra of Si IV and O IV. The electron beam drives the plasma out of equilibrium. At electron densities of N-e = 10(10) cm(-3), the plasma is out of ionization equilibrium at all times in all cases we considered, while for a higher density of N-e = 10(11) cm(-3), ionization equilibrium can be reached toward the end of each period, depending on the conditions. In turn, the character of the period-averaged synthetic spectra also depends on the properties of the beam. While the case of kappa = 2 results in spectra with strong or even dominant O IV, higher values of kappa can approximate a range of observed TR spectra. Spectra similar to typically observed spectra, with the Si IV 1402.8 angstrom line about a factor 5 higher than O IV 1401.2 angstrom, are obtained for kappa = 3. An even higher value of kappa = 5 results in spectra that are exclusively dominated by Si IV, with negligible O IV emission. This is a possible interpretation of the TR spectra of UV (Ellerman) bursts, although an interpretation that requires a density that is 1-3 orders of magnitude lower than for equilibrium estimates.nn

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2018

Confidentiality

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

Name of the periodical

Astronomy & Astrophysics

ISSN

1432-0746

e-ISSN

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Volume of the periodical

610

Issue of the periodical within the volume

March

Country of publishing house

FR - FRANCE

Number of pages

12

Pages from-to

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UT code for WoS article

000427139000005

EID of the result in the Scopus database

2-s2.0-85042885763