FORCASTING OF SOLAR FLARES

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80T00246A024000050001-9
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 11
• Document Creation Date: December 23, 2016
• Document Release Date: August 21, 2013
• Sequence Number: 1
• Publication Date: November 4, 1963
• Content Type: REPORT

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FORECASTING OF SOLAR FLARES
S. I. Gopasyuk, M. B. Ogir, A. B. Severny, N. V. Steshenko,
E. F. Shaposhnikova
Crimean Astrophysical Observatory
Nauchny, Crimea, U.S.S.R.
The magnetic fields of cosmic ray flares and some other flares
appearing during 1957 - 1962 have been examined at the Crimean
Astrophysical Observatory. Magnetic fields before and after flares
determined visually and photographically in groups of sunspots were
analyzed in nearly 50 cases. These determinations were carried
out during the IGY in a regular program basis at six different
observatories. The complete number of observations being three to
four per day. During the 1959 - 1962 period, observations made
twice a day at the Crimean Observatory were used.
All of the flares were divided into four classes as indicated
in table I. She flares, typical for each class, were chosen on the
basis of the presence of the reliable data about the field configura-
tions before and atter a flare as well as on the data about the
generation of cosmic rays and of geophysical effects produced by flare.
Well pronounced Changes of configurations of magnetic fields
were found when comparing them before and after a flare. Namely,
in most cases we found that the magnetic polarities of the opposite
sense are approached a little and the 3-d pole is pushed out (see fig. 1).
It was found (see table I) that the importance of a flare (and its duration)
depend strongly on the gradient of magnetic field near its neutral point.
Namely, the more is the gradient, the more is the 'importance of a flare.
STAT
STAT
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These gradients were Obtained by the construction of a laboratory model
of the transverse field of the configuration observed (the position of
the poles and their strengths) by using the similarity relations for
the gradient of transversal field in the region near the neutral point.
There were no flares of the importance 3 with the gradient smaller
0.1 gs/km, as well as there were no flares of importance ?2 with the
gradient exceeding this value. (For the detailed description see ref-
erence 1).
Table I
The an gradients of magnetic fields before and after a flare.
Class Type of flares Number Gradient of field DUration
Not of gs/km of
flares ? cases before after flares
a flare
I
C.R" Protons
13
C.73
0.25
0.17
(balloons)
II
Protons
11
0.46
0.27
0.089
(Pm) .
III
Imp. 3 without
12
0.18
0.13
0.071
PCA.
IV
2+ and 2 (usual)
15,
0.054
0.038
0x48
On the fig. 2 - 3 the gradient of magnetic field before and after
flares are shown (the values before and after flares are joined by
straight line, the part of which corresponding to the duration of flare
is thick. The gradients of magnetic fields diminish considerably atter
a flare and the decrease is the higher the more important is a flare.
The biggest chance of the gradient is observed for flares with cosmic
ray effects on balloons and for flares producing PCA.
? . ?
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[-,
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For the forecasts of flare importances with the help of the magnetic
fields it is necessary to have the most complete and perfect data
about the fields. The experimental forecasts were given during 1961 -
1962. During this period we mainly used the detailed measurements
of the absolute magnetic fields made at the Crimean Astrophysical
Observatory. Besides that the observations made at Poulkovo Observatory,
Mountains Astronomical Station at Kislovodsk and ISMIR (Moscow) were
used. The maps of the longitudinal field recorded by magnetograph
of the Crimean Astrophysical Observatory were of importance for this
work. Our experience shows, that the existence of "invisible spots" -
regions of increasing field strength which are not accompanied by any
formations in visible light makes it necessary to have even rough map
of the field (some hundreds of gauss), while the mean error of the
current visual measurements of the field is + 200 gs.
The data on the magnetic fields near the limb become uncertain.
The forecast with the use of magnetic fields is practically impossible
during a day after the first appearance of the group at the eastern
limb. The same is true for a.day before the passage of group into
Invisible hemisphere at the western limb. Our experience of fore-
casts also shows that the most rapid serious changes of configura-
tions of the field, as well as the formation of groups, take time in
about a day and even less. Therefore the forecast for more than two
days can have some error.
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We use the following meaning for forecast: 1 - means that no
flares are expected or there can be flares of importance 1 1 and
1+; the forecast 2 - means that the flares of the importance 1+,
2 and 2+ are expected. The forecast 3 - has the same meaning as
above but for flares of the importance 2+, 3 and 3+. The value 5-
means that the forecast is impossible because the lack of data.
The flares of importance 1+ are included simultaneously in the
forecasts 1 and 2, (as well as flares of the importance 2+ are
present simultaneously in the forecasts 2 and 3) because the lack
of clear distinction between the importances of flares and the
posiderable error in the estimates (the error of 0.5 of the scale
adopted is quite usual.)
Table II
Forecast of flares for 1962
Number of cases Correct Overestimated Underestimated
102
l00%
77
75.9%
13
12.1
12
Fig. 4 contains the numbers of different forecasts of the flare,
importances for the time interval of 2 days; true forecasts (dots),
overestimated (crosses), underestimated - most dangerous (triangles);
open circles are the sum of true and overestimated forecasts - it
can be considereeis the "measure of safety".
4
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It is obvious that forecasts become less reliable with the increase
of time interval, and from fig. 4 we see that the flare forecast is
effective for time interval no more than 2 - 3 days, when the number
of unforeseen flares does not exceed 15 - 20% of total amount. For
the bigger time interval the number of underestimated forecasts increases
rapidly and for 5 and more days the forecasts are not particularly
effective.
The forecasts for the active regions near the limb are not certain
when using the magnetic fields only and we should appeal in this case
to some other solar phenomena such as the motions of the chromospheric
filaments, the appearence of "moustaches" - very broad emission wings
of lines, the brightness of the plages, the intensity of the radio-
emission and some other.
ref I S. I. Gopasyuk, M. B. Ogir, A. B. Severny, E. F. Shaposhnikova.
The structure of magnetic fields and its change in the region
of solar flares, Isvestija.Crim. Aph. Obs. 29,
(in press)
STAT
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Figure Captions
1. Typical magnetic field gemetry before and after a flare (primes
refer to after).
2. Changes in the ma,gnetic field gradient near flare tims for flares
of class I and II.
3. Changes in the magnetic field gradient near flare tines for flares
of class III and IV.
4. Is given on figure.
n Ir. fl A, e e ^ An ,? ? ? AV gn finkn e. .4. AI ? .0 ?
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1 t'
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1S.X1.60
Fig. 2
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ism111.58
GAUSS/KILOMETER
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1.5
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GAUSS/ KILOMETER
Fig.3
1.0
0.5
16.X.57
1.5.58
I 5.VI 1.58
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PERCENT
1 2 3 4 5 6 7 8 9 10
1 correct forecasts
2? overestimated forecasts
3?Underestimated forecasts
4?Sum or correct and overestimated forecast
Fig.4. Justification of forecasts for 1962
. " ??? . "AP,
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1
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