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(Week 08, 2003, 17 Feb. - 23 Feb.)
In the display above (click to enlarge), the solar X-ray fluence seen by RESIK (black points) is plotted atop GOES red line. Only periods with good spectral measurements are indicated. The total number of good spectral measurements is given in the title line.
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Operation mode: |
Since 08 February 2003 the DGI rate has been set to 4 s. '3rd order reflections' (ORD3) is used as stand by mode. 3rd order measurements are indicated on the main catalogue page http://www.cbk.pan.wroc.pl/resik_catalogue.htm (cf. green boxes).
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Calibrations made: |
No calibrations made
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ADS Settings: |
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| (ORD1) HV: Det. A - 1450 V, Det. B - 1419 V. | (ORD3) HV: Det. A - 1389 V, Det. B - 1328 V. | ||||||
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Channel |
l Band |
ADS |
Channel |
l Band |
ADS | ||
| #1 | #2 | 3.37 - 3.88 Å | 55 - 110 | #1 | #2 | 1.16 - 1.29 Å | 110 - 230 |
| #2 | #0 | 3.82 - 4.33 Å | 80 - 165 | #2 | #0 | 1.27 - 1.44 Å | 110 - 230 |
| #3 | #3 | 4.31 - 4.89 Å | 90 - 160 | #3 | #3 | 1.44 - 1.63 Å | 110 - 230 |
| #4 | #1 | 4.96 - 6.09 Å | 135 - 200 | #4 | #1 | 1.65 - 2.03 Å | 140 - 230 |
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 spectroscopic notation
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Data gaps due to missing telemetry: ~ 9 h.
Note, that the link to the catalogue page is now: http://www.cbk.pan.wroc.pl/resik_catalogue.htm.
Potassium Enhanced Flare
Presently, the solar activity is on the 23rd cycle decay. Although the maximum of activity is only two years behind, recent X-ray activity level is unexpectedly low. Therefore every observed flare is now of special interest.
Last week a short lasting event (start at 09:24:00 UT, maximum at 09:29:00 UT, end at 09:31:00 UT) of C5.8 importance (Hα subflare) has been observed well on the solar disc (N16W05). This is an interesting flare as its rise and decay times are of similar duration which does not happen in general. It turns out that this event is also peculiar in respect to the spectra observed.
In Figure 3 we present spectrum of this flare as collected for the entire event. A number of strong lines is seen, characteristic to quite a hot plasma. In addition the K XVIII triplet lines are clearly present. As potassium is belived (based on the photospheric estimates) to belong to a „poor” element abundance class this observation indicates for unusual plasma composition.
Figure 1.
The RESIK Catalogue page containing the presented flare on 22nd February 2003 at ~ 09:30 UT. Note that the S/C is out of Earth's shadow (see Week 03, 2003).
Figure 2. The RESIK (in green) and GOES fluxes for the C5.8 class flare on 22nd February 2003 at ~ 09:28 UT (zoomed from Figure 1). The observed „delay” of RESIK rise phase is not easy to understand at present. Suspected is GOES sampling time (1 min).
Figure 3.
The spectra for all RESIK channels collected over the entire flare (~10 min). Ions responsible for the stronger lines are indicated (see Week 40, 2002 for more details).
Figure 4.
RESIK spectra integrated over the rise (top, red) and decay phase (bottom, blue). The thick arrows above the spectra point to spectral features we have selected for analysis of the time variations. They are He-like ion triplets: K XVIII (red), Ar XVII (blue), S XV (yellow) and H-like S XVI ion Lyα line (light brown). We have selected also the continua near-by respective lines (same colours) and displayed line and continuum lightcurves in Figure 5 (left and right panels respectively).
Figure 5.
The time variations of the intensities as measured in the four lines selected (left) and the near-by continua (right). The colour coding used is the following: red - K XVIII triplet (and respective continuum), blue - Ar XVII triplet (and respective continuum), light brown - Lyα line of S XVI (and respective continuum), yellow - S XV triplet (and respective continuum).Report prepared by: Barbara Sylwester bs@cbk.pan.wroc.pl and Janusz Sylwester js@cbk.pan.wroc.pl
The report presented has been done in "real time" and so it may contain
jargon, blunders, or trivialities. We do not have also an English native speaker
in our Wroclaw group! We would be happy to discuss problems mentioned above in
more details if necessary.
RESIK data are in the open public domain and
can be requested from: http://surfwww.mssl.ucl.ac.uk/surf/data_request.html.
Previous RESIK_weekly notes are in the archive: http://www.cbk.pan.wroc.pl/resik_archive.htm
Page made on 28 February 2003 by: Anna Kepa ak@cbk.pan.wroc.pl and Jarek Bakala jb@cbk.pan.wroc.pl
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