Yohkoh SXT image of solar X-ray
activity for Carrington rotation 1861
(October 3 - 31, 1992)
At 1800 UT on October 30, 1992, the solar (1-8 Å)
X-ray irradiance measured by the GOES-7 satellite abruptly increased by a
factor of 100, decaying down to its previous values over a 12-hour period. At
the same time, increases were seen in energetic (> 200 eV) photoelectrons
measured by the
UARS Particle Environment Monitor
(PEM),
and a factor of 2-3 increase in the atomic oxygen
5577 Å
airglow intensity was recorded by the UARS Wind Imaging Interferometer (WINDII) at altitudes
90 - 120 km, with smaller increases in the F1 region.
This study examines the production of excited
O(1S) from energetic photoelectron impact on O and
O2, reaction of metastable N2(A) with O,
dissociative recombination of O2+, and
dissociation of O2 by solar Lyman beta.
The results suggest that while O(1S) increases due to the
solar flare, no corresponding increases will be seen in the
O(1D) 6300 Å or
O2(b) Atmospheric Band emissions
since these are dominated by processes arising from photoabsorption in the
Schumann-Runge continuum of O2. The UARS far ultraviolet solar
irradiance monitors
SOLSTICE
and
SUSIM
noted no significant increase in this spectral region. Preliminary
analysis of the O2 Atmospheric Bands is consistent with this
conclusion. Although the 6300 Å filter was inactive during this flare
period, lack of a large increase in O2(b) emission,
arising partly from O(1D) + O2 suggests that
O(1D) does not increase substantially.
An outline of the data analysis strategy appears
here.
