Determination of the electronic concentration in a bright solar prominence
A spectrum of a bright prominence on April 1, 1970 is analysed. The prominence partly projected onto the solar disc near the limb where many emissive spectral lines were observed. The spectral intensity distributions in prominence and outside it were compared to derive the pure emission of prominenc...
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| Veröffentlicht in: | Кинематика и физика небесных тел |
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| Datum: | 2005 |
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Головна астрономічна обсерваторія НАН України
2005
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| Zitieren: | Determination of the electronic concentration in a bright solar prominence / E.R. Venglinsky, L.M. Kostenko // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 146-147. — Бібліогр.: 5 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859733668106338304 |
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| author | Venglinsky, E.R. Kostenko, L.M. |
| author_facet | Venglinsky, E.R. Kostenko, L.M. |
| citation_txt | Determination of the electronic concentration in a bright solar prominence / E.R. Venglinsky, L.M. Kostenko // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 146-147. — Бібліогр.: 5 назв. — англ. |
| collection | DSpace DC |
| container_title | Кинематика и физика небесных тел |
| description | A spectrum of a bright prominence on April 1, 1970 is analysed. The prominence partly projected onto the solar disc near the limb where many emissive spectral lines were observed. The spectral intensity distributions in prominence and outside it were compared to derive the pure emission of prominence. Such obtained observed spectra were compared with theoretical ones calculated for the spectral region from the 18th Balmer line to series limit, and for different electronic concentrations. It was found that reliable determined electronic concentrations were in the range 10¹⁷–10¹⁸ m⁻³, i.e., 3–4 order more than in quiet solar corona. It is argued that our method for the electron concentration determination is more reliable than one proposed before by Kurochka [3], based on the analysis of the intensity increase of the continuum spectra in range of the Balmer pre-continuum.
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| first_indexed | 2025-12-01T14:12:05Z |
| format | Article |
| fulltext |
DETERMINATION OF THE ELECTRONIC CONCENTRATION
IN A BRIGHT SOLAR PROMINENCE
E. R. Venglinsky, L. M. Kostenko
Astronomical Observatory, National Taras Shevchenko University of Kyiv
3 Observatorna Str., 04053 Kyiv, Ukraine
A spectrum of a bright prominence on April 1, 1970 is analysed. The prominence partly projected
onto the solar disc near the limb where many emissive spectral lines were observed. The spectral
intensity distributions in prominence and outside it were compared to derive the pure emission
of prominence. Such obtained observed spectra were compared with theoretical ones calculated
for the spectral region from the 18th Balmer line to series limit, and for different electronic con-
centrations. It was found that reliable determined electronic concentrations were in the range
1017– 1018 m−3, i.e., 3–4 order more than in quiet solar corona. It is argued that our method for
the electron concentration determination is more reliable than one proposed before by Kurochka [3],
based on the analysis of the intensity increase of the continuum spectra in range of the Balmer
pre-continuum.
INTRODUCTION
Electronic concentration represents a very important parameter of astrophysics objects. The most employed
method for determination of the electronic concentration bases on the Inglis–Teller formula [2]:
log Ne = 22.7 − 7.5 logN, (1)
where N is the last spectrally resolved line of the Balmer hydrogen spectrum.
Another method for this purpose was proposed earlier by Kurochka [3], who used a character of energy
increase in spectral continuum near to region of transformation of the discrete Balmer spectrum into continuous
emission. To obtain such energy increase, an interpolation curve was constructed using spectral intensities
between the spectral Balmer lines. This interpolate curve was named pre-continuum in [3]. It was supposed
that the following observational data would allow one to determine not only mean electronic concentration
but also distribution of the measure emission versus electronic concentration. However, as it was shown later
in [5], only two first moments of distributions really could be determined with this approach taking into account
the ordinary accuracy of the observations.
At present paper we use a more adequate method based on an approximation of the full observed Balmer
spectrum with several tens of spectral lines of wavelengths from 3660 to 3700 Å by synthetic spectrum. Moreover,
we analyse unique spectral data related to spectral peculiarities of the exclusively bright prominence.
MODEL AND METHOD OF CALCULATION
We try to determine the electronic concentration in solar prominence using the comparison of the real observed
spectrum with the calculated synthetic Balmer spectrum. As an observed spectrum, we used the Balmer
spectrum of a bright solar prominence which was observed by Dr. A. S. Rakhubovsky on April 1, 1970 at
the Main Astronomical Observatory of the Academy of Sciences of Ukraine.
The brightnest part of prominence projected partly onto solar disc was analysed. To obtain the spectrum of
proper solar prominence, the photometry of a place close to prominence was carried out, but outside one. After
this photometry, the second spectral distribution was subtracted from the first one giving a pure emission of
prominence.
The spectral region from 3660 to 3700 Å was investigated by a step of 0.04 Å. Observed and calculated
spectra are given in Fig. 1 in units of I/Ic, where I is the energy in an arbitrary point of spectrum, and Ic is
the energy at the Balmer series limit.
The synthetic Balmer spectrum was calculated for the temperature T = 7000 K, a probable velocity of
hydrogen atom of 10 000 m/s, and for the electronic concentration Ne from log Ne = 16 to log Ne = 19.25, with
a step of 0.25.
c© E. R. Venglinsky, L. M. Kostenko, 2004
146
Figure 1. Observed and theoretical spectra: solid line denotes observations and dash-dot line is for the synthetic Balmer
spectrum. Energy is given in units of the Balmer continuum level jump
In order to calculate the profiles of the Balmer lines by charged particle influences, the quasistatic widening
from ions and blow expansion from electrons [4] (for central parts of lines) were taken into account. For wings
of the lines, the gradual conversion from blow extension to quasistatic one was calculated [1]. After these
calculations, a convolution of obtained profiles with Doppler ones were made. Contribution of the partial
electronic concentrations was determined by the least-squares method using the limitation of non-negative
spectral intensities.
As a result, non-zero contribution in line profiles was found the following parameters: log Ne = 17.25 (6.2%),
log Ne = 17.5 (8.2%), log Ne = 17.75 (50.8%), log Ne = 18.0 (33.3%), and log Ne = 19.25 (1.5%). The last
value, log Ne = 19.25, is maximum in our calculations, and likely one does not influence the Balmer spectrum
because such high electronic concentrations give the forming contributions in spectral continuum only.
Formal presence of such a high value of log Ne could explain the Tompson dispersion. We can not take into
account this value as likely unreliable. In this case, the middle value of log Ne is 17.78.
As it was pointed above, only two first moments of distributions really could be determined taking into
account the ordinary accuracy of the observations. Therefore, it is possible to replace above presented distri-
bution of log Ne by the rectangular one, using the middle value of log Ne = 17.78 and the range of dispersion
from log Ne = 17.53 to log Ne = 18.03.
Thus, as the dispersion range is relatively narrow, it is acceptable to calculate theoretical spectra using one
middle value of log Ne only.
[1] Grim G. Expansion of the spectral lines in plasma.–Moscow, 1978. (in Russian).
[2] Inglis D. R., Teller E. Ionic depression of series limits in one-electron spectra // Astrophys. J.–1939.–90, N 3.–
P. 439–448.
[3] Kurochka L. N. Registration of the micro- and macroinhomogeneities of plasma density in the astrophysical ob-
jects // Kinematics and Physics of Celestial Bodies.–1991.–7.–P. 31–37.
[4] Vainstein L. A., Sobelman I. I., Yudkov E. A. Excitation of atoms and expansion of the spectral lines.–Moscow,
1979. (in Russian).
[5] Venglinsky E. R. Analysis of the accuracy of determination of the inhomogeneity of the electronic concentration
in solar emissive features // Visnyk Kyiv Univ. Astronomia.–2002.–38.–P. 5–9.
147
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| id | nasplib_isofts_kiev_ua-123456789-79628 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0233-7665 |
| language | English |
| last_indexed | 2025-12-01T14:12:05Z |
| publishDate | 2005 |
| publisher | Головна астрономічна обсерваторія НАН України |
| record_format | dspace |
| spelling | Venglinsky, E.R. Kostenko, L.M. 2015-04-03T16:32:30Z 2015-04-03T16:32:30Z 2005 Determination of the electronic concentration in a bright solar prominence / E.R. Venglinsky, L.M. Kostenko // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 146-147. — Бібліогр.: 5 назв. — англ. 0233-7665 https://nasplib.isofts.kiev.ua/handle/123456789/79628 A spectrum of a bright prominence on April 1, 1970 is analysed. The prominence partly projected onto the solar disc near the limb where many emissive spectral lines were observed. The spectral intensity distributions in prominence and outside it were compared to derive the pure emission of prominence. Such obtained observed spectra were compared with theoretical ones calculated for the spectral region from the 18th Balmer line to series limit, and for different electronic concentrations. It was found that reliable determined electronic concentrations were in the range 10¹⁷–10¹⁸ m⁻³, i.e., 3–4 order more than in quiet solar corona. It is argued that our method for the electron concentration determination is more reliable than one proposed before by Kurochka [3], based on the analysis of the intensity increase of the continuum spectra in range of the Balmer pre-continuum. en Головна астрономічна обсерваторія НАН України Кинематика и физика небесных тел MS2: Physics of Solar Atmosphere Determination of the electronic concentration in a bright solar prominence Article published earlier |
| spellingShingle | Determination of the electronic concentration in a bright solar prominence Venglinsky, E.R. Kostenko, L.M. MS2: Physics of Solar Atmosphere |
| title | Determination of the electronic concentration in a bright solar prominence |
| title_full | Determination of the electronic concentration in a bright solar prominence |
| title_fullStr | Determination of the electronic concentration in a bright solar prominence |
| title_full_unstemmed | Determination of the electronic concentration in a bright solar prominence |
| title_short | Determination of the electronic concentration in a bright solar prominence |
| title_sort | determination of the electronic concentration in a bright solar prominence |
| topic | MS2: Physics of Solar Atmosphere |
| topic_facet | MS2: Physics of Solar Atmosphere |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/79628 |
| work_keys_str_mv | AT venglinskyer determinationoftheelectronicconcentrationinabrightsolarprominence AT kostenkolm determinationoftheelectronicconcentrationinabrightsolarprominence |