Issue |
A&A
Volume 495, Number 2, February IV 2009
|
|
---|---|---|
Page(s) | 613 - 620 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361:20066547 | |
Published online | 22 December 2008 |
The solar plasma conditions in the source regions of two explosive events
1
Instituto Nacional de Astrofísica, Optica y Electrónica, Apartado Postal 51 y 216, Puebla, Pue., Z.P. 72000, México e-mail: mend@inaoep.mx
2
Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany
3
Instituto de Geofísica, UNAM, México
Received:
11
October
2006
Accepted:
7
November
2008
We analyze the ultraviolet emission during
two explosive events (EEI and EEII) recorded by SUMER aboard
SOHO in the wavelength range from 749 Å to 789 Å.
The events occurred near the centre
of the solar disk on 17 November 1996.
An attempt is made to separate the emission
of the primary energy release from that of the accelerated plasma.
We want to establish the characteristics of the sources,
in particular, how large they are and how they are spatially
distributed with respect to each other.
Gaussian fits were calculated to estimate the radiances of the
brightest emissions in our wavelength range for the core of the
lines and their blue and red wings.
The maximum of each Gaussian approximation was used to define the spatial
distributions of the components.
The electron densities were obtained with the help of the
O v line ratio.
The relationship between the densities and the spatial
distribution of the radiances is then analyzed.
The distributions of EEI are more extended than those of EEII,
probably due to the different geometries of the observations.
In both events, there is an offset in the locations of red
and blue components but the offset is greater at EEI than at EEII.
The Doppler velocities of the components of EEI were smaller
than those of EEII.
Also, in both events the density of the red component attained
the highest values ( cm-3).
In EEI the electron density distributions of the three
components were considerably narrower than the radiance distributions.
The peak densities were observed centred with respect to the radiance
distributions, suggesting that the sources of the first energy release
of this event were near these locations.
Both the electron density and the radiance distributions of EEI
suggest a jet direction close to the line of sight.
Key words: Sun: transition region / Sun: activity / Sun: UV radiation
© ESO, 2009
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