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Airglow atmospheric imager on board the ‘IK-Bulgaria-1300’ satellite
Adv. Space Res.
Vol.2, No.7, pp.l15-120, 1983 Printed in Great Britain. All rights reserved.
0273-1177/83/070115-06503.00/0 Copyright © COSPAR
A I R G L O W A T M O S P H E R I C IMAGER ON B O A R D THE 'IK-BULGARIA-1300' SATELLITE M. Gogoshev*, N. Petkov*, A. Kuzmin**, Ts. Gogosheva*, St. Spassov* and Iv. Kostadinov* *Central Laboratory for Space Research, Bulgarian Academy of Sciences, Bulgaria **Space Research Institute Academy of Sciences, U.S.S.R. ABSTRACT
T h i s p a p e r s h o w s the p o s s i b i l i t i e s o f the o p t i c a l s c a n n i n g i m a g e r f o r i n v e s t i g a t i o n o f the s t r u c t u r e o f the a u r o r a / , S A R and tropical arcs and in this w a y to s t u d y the p a r t i c l e p r e c i p i t a t i o n , n e u t r a l w i n d s a c r o s s the m a g n e t i c e q u a t o r , d r i f t s , e l e c t r i c f i e l d s a n d the c u r r e n t s y s t e m s i n t h e i o n o s p h e r e . INTRODUCTION T h e m a i n p a r t o f the b a s i c a e r o n o m i c a n d d y n a m i c a l p h e n o m e n a i n the u p p e r a t m o s p h e r e o f the E a r t h and p a r t i c ~ l a r l y of the i o n i z e d p a r t is c o n n e c t e d w i ~ h the i n t e n s i f i c a t i o n o f the o p t i c a l e m i s s i o n s . T h e intensities at m i d and low latitudes are comparatively low and except for hydroxyl and some oxygen emissions in the D and E regions,don't show clear spatial structure. F o r o x y g e n , the s r u c t u r e is c l e a r l y e x p r e s s e d a t h i g h g e o m a g n e t i c latitude a n d i n the r e g i o n o f the g e o m a g n e t i c e q u a t o r . T h e s t r u c t u r e a n d the d y n a m i c s o f the S A R - a r c and o f tile d i s c r e t e a r c s i n the a u r o r a a r e o f c o n s i d e r a b l e interest for the magnetospheric-ionospheric relations.In the l a s t f e w y e a r s i t b e c a m e c l e a r t h a t i n the r e g i o n o f the geomagnetic equator there are discrete optical ionospheric structures (ar~s) ,which huve comparatively h i g h v a l u e s o f the e m i s s i o n s i n the v i s i b l e a n d i n t h e UY p a r t o f the s p e c t r u m [1,2,3] , T h e t r o p i c a l a n d the equatorial arcs which are observed,a~e c l o s e l y r e l a t e d to the e q u a t o r i a l anomaly,transequatorial p l a s m a t r a n s f e r a n d w i t h the e l e c t r o s t a t i c field, g e n e r a t e d i n t h e r e g i o n o f the g e o m a g n e t i c e q u a t o r . A number of satellite experiments h a v e b e e n d e v o t e d to the p r o b l e m o f the structures i n the g l o w i n g a t m o s p h e r i c r e g i o n s a n d o f a u r o r a . 0 n b o a r d 0G0-II there was a scanning optical photometer[4] ,but since the insrum e n t o p t i c a l a x i s w a s d i r e c t e d t o w a r d the h o r i z o n , v e r t i c a l p r o f i l e s w e r e measured,butnot t h e h o r i z o n t a l s p a t i a l s t r u c t u r e o f the a i r g l o w . T h e o b s e r v a t i o n s w i t h O G O - 4 u s e d to p r o d u c e s p a c e m a p s f o r the g l o b a l d i s t r i b u t i o n o f the m a i n o p t i c a l e m i s s i o n s w e r e a n a l o g o u s [5] . Many successful observations of SAR-arcs a n d o f the d i s c r e t e a u r o r a structures a n d o f the c u s p s t r u c t u r e s w e r e m a d e b y the s c a n n i n g p h o t o m e t e r anO b y t h e r e d - ~ i n e p h o t o m e t e r o n b o a r d I S I S - I I . T h e nesolution o f the instruments was 0,4 .VAE--%he i n s t r u m e n t o n b o a r d " A t m o s p h e r i c Explorer" [10] a l s o m a d e i t p o s s i b l e to s t u d y the s t r u c t u r e o f the o p t i cal a t m o s p h e r i c emissions,but essentially in a vertical direction.
[6,7,8,9]
The DMSP-satellite [11] g a v e the p o s s i b i l i t y to o b t a i n n o t o n l y the auroral fine structure,but also a number of different observations and possibilities of comparison with different satellites and ground-based data.A new possibility of investigation o f the d i s c r e t e s t r u c t u r e s and o f the p o l a r o v a l is g i v e n b y D y n a m i c s E x p l o r e r . The global auroral imaging instrument on board DE-A allows a continued observation o f the w h o l e p i c t u r e o f tile p o l a r o v a l i n a n u m b e r o f s p e c tral l i n e s [12] b u t w i t h c o m p a r a t i v e l y low spacialresolution. Further wet11 g a r i a 1300".
describe
the A i r g l o w
imager
115
on board
the
satellite
"IK-Bul-
116
M. Gogoshev et aZ.
"IK-BULGARIA
S±tTELLITE
1300"
The satellite "IK-Bulgaria 1300" was launched in a near circular orbit 9 0 5 / 8 2 4 km, i n c l i n a t i o n 82,5 ° on 7-th August, 1981.The main scientific goal i s the i n v e s t i g a t i o n o f the c o m p l i c a t e d n a t u r e o f m a g n e t e s p h e r i c - i o n o s p b e r ic p h e n o m e n a and r e l a t i o n s . F o r t h i s p u r p o s e the f o l l o w i n g p a r a m e t e r s are measured on board:Thermal plasma,electric fields,magnetic field,electron ar~i p r o t o n s p e c t r u m i n the r a n g e o f 2 0 0 e v to IMev, d r i f t , a n d o p t i c a l g l o w in a large spectral range including UV emissions [13] . F u r t h e r w e ' l l d w e l l in particular o n o n e o f the o p t i c a l i n s t r u m e n t s o n b o a r d - t h e two c h a n n e l scanning photometer E M O - 5 w h i c h w o r k s i n the v i s i b l e p a r t o f s p e c t r u m . B o t h o p t i c a l c h a n n e l s o f the i n s t r u m e n t l o o k to the n a d i r ( t h e s a t e l l i t e is three axis stabilized with an accuracy of stabilization b e t t e r t h a n - + I°). The channels have 8 interference f i l t e r s to m e a s u r e the i n t e n s i t i e s o f the following optical emissions i n the s u b s a t e l l i t e region: ~ 6300 A (0I),
5577 X ( O I )
9
.~
4
278 A Neg.N +o ) , " (I
~ 4861 X (H ~ )
A 7320 k(O I I )
a n d i n the l i n e A 6345 A by w h i c h ~ t h e s p e c t r a l buckgrouncl is d e t e r m i n e d . A t the s e v e n t h and the e i g h t h p o s i t i o n o f the w h e e l are m e a s u r e d the d a r k c u r r e n t a n d the i n t e n s i t y o f the r a d i o a c t i v e s o ~ r c e . T h e w h e e l w i t h the f i l t e r s m a k e s a f u l l r e v o l u t i o n e v e r y 16 s e e . T h e n e c e s s a r y time f o r m e a s u r e ment i n e a c h p o s i t i o n is 1 , S s e c . O n e m i c r o c o o l e r (Peltier effect)gives the possibility to l o w e r the p h o t o m u l t i p l i e r t e m p e r a t u r e to 35 ~ b e l o w t h e t e m p e r a t u r e o f the case. T h e o p t i c a l p r o t e c t i o n o f the c n a n n a l is a c h i e v e d b y a s h u t t e r . T h e i n s t r u m e n t is d e s c r i b e d i n m o r e d e t a i l i n [141 . 6300
A
SCANNING
IMt%GER
I n the s e c o n d o p t i c a l c h a n n e l o f the i n s t r u m e n t E M 0 - 5 is a n i n t e r f e r e n c e f i l t e r p e a k e d at ~ 6 3 0 5 A w i t h b a n d w i d t h 15 A, ~ =40%,and a scanning optical system.The s c a n n i n g is p e r p e n d i c u l a r to t h e m a X s a t e l l i t e m o t i o n . T h e o p t i c a l s c h e m e o f t h e i m a g e r is s h o w n i n F i g . 1.The i n s t r u m e n t a l field of
HO TOR
Fig. I
The
optical
scheme
of
the
scanning
channel
o
v i e w is 3 . A f t e r h t h e o p t i c a l b a f f l e w i t h a c o e f f i c i e n t o f a t t e n u a t i o n b e t t e r t h a n 5. 10- is a n e n t r a n c e p l a n e m i r r o r , ib/ m o v i n g t h i s s c a n n i n g m i r ror, the o p t i c a l a x i s , w h i c h i S o r i e n t e d t o t h e n a d i r , c a n b e m o v e d to + 15 ° . T h e b,lock s c h e m e f o r the s c a n n i n g m i r r o r c o n t r o l is s h o w n i n F ig. 2 . A v a c u u m stepping m o t o r and w o r m d r i v e is u s e d . 0 n e s i n g l e s c a n o f tlle i n s t r u m e n t (from-15 to +15 °) is m a d e i n I sec. T h e m o t i o n o f the m i r r o r is c o n t i n u o u s w i t h m a r k e r s at s e v e n d i f f e r e n t p o s i t i o n s . W h e n the c o m p a r a t o r f o r a l o g i c a l and o p t i c a l p r o t e c t i o n g i v e s a s i g n a l , t h e s c a n n i n g m i r r o r is a u t o m a t i c a l l y f i x e d at a m i d d l e p o s i t i o n ( l o o k i n g to the n a d i r ) . T h e l o g i c o f the motion control besides the program, can also mand f o r s w i t c h i n g on and s w i t c h i n g off.
use
s~pplementary
grot~nd
com-
Airglow Atmospheric
Imager
[17
COh'IPARATOR OPTICAL PROTECTION I lsec SYNCHRONIZING PULSE COMPARATOR LOGIC PROTECTION h
~1
II I PULSE I
H
I
I
SITIO,,t__,. r--q
----'I!OG'C 'lCOUNTER 2I
l]
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M,R,OR
-
I ~ WITCHING ON SCANNING STAIR- CASE
TA
DAc
I
II
}
II
POSITION~.----./ .,-5v ~ ~÷15v SWITCHES STEPPING POWER MOTOR AND WORM DRIVE
Fig. 2
The
block
diagram
of
the
scanning
mirr&r
control
i n a n o r m a l mode o f o p e r a t i o n one s i n g l e s c a n c o n t a i n s 7 pJxels. The p i x e l dimensions at the l e v e l o f F m a x ( w e assume 270 km) are 8x52 k m . T h e f i r s t v a l u e is o b t a i n e d by some o v e r l a p o f the f i e l d of v i e w in the d i r e c t i o n of s a t e l l i t e m o % i o n . l n this w a y we h a v e a b e t t e r o p p o r t u n i t y to i n v e s t i g a t e zo n a l strttctures. T h e t h r e s h o l d s e n s i v i t y o f the w h e n the i n s t r u m e n t p r o t e c t i o n
c h a n n a l is 50 R, and the u p p e r c i r c u i t y is a c t i v a t e d .
limit-120kR,
DATA ANALYSIS A map of i n t e n s i t y d i s t r i b u t i o n s , t a k e n by the s c a n n i n g i m a g e r o n b o a r d " I K - ~ u l g a r i a 1300" on A u g u s t 1 9 8 1 , o r b i t 213 is s h o w n in Fig. 3 . T h e i n t e n s i t y d i s t r i b u t i o n of I ~ ^ _ ^ is s h o w n i n 5 d i s c r e t e l e v e l s w i t h 100 R, 100-150 R, 150-200 R, 2 0 0 - 3 0 0 - 3 u u R . a n d more t h a n 300 R . T h e r e g i o n s of the N o r t h tropical a ~ c ( ~ ~ 5 ° , A @ ~ 1 8 O) a n d o f t h e S o u t h t r o p i c a l arc (qgeo~r. 7 , J[@=24 ge°gr" ) are well o u t l i n e d . T h e m a x i m u m i n t e n s i t i e s i n the n o r t h e r n arc e x c e e d 200 R and i n the S o u t h they are a b o u t 150 R.We must n o t e that o n the p i c t u r e 15 s c a n a v a r a g l n g is used. I n the l o w e r p a r t o f the figure the i n t e n s i t y i n c r e a s e is r e l a t e d w i t h the s a t e l l i t e a p p r o a c h to the s u n l i t a t m o s p h e r e . O n the o t h e r o r b i t s the t y p i c a l level for A p p e l t o n l s a i r g l o w a n o m a l y ( t r o p i c a l arcs) i n 6 3 0 0 ~ is o b v i o u s . Some d a t a s h o w the a s s y m e t r y in the a r c s , p r o b a b l y r e l a t e d w i t h the i n f l u e n c e o f n e u t r a l w i n d s and d r i f t s . ~ h e 6 3 0 0 A S c a n n e r I m a g e r p o s s i b i l i t i e s , c a n be i l l u s t r a t e d by Fig. 4 r e f e r r e d to o r b i t N o . 2 0 3 ( 21 A u g u s t , 1 9 8 1 ) . H e r e are s h o w n the m e a s u r e d i n t e n s i t i e s f r o m the f i r s t c h a n n e l w i t h the b a c k g r o u n d f r o m the s i x t h c h a n n e l r e m o v e d . T h e d i f f u s e a u r o r a l r e g i o n b e g i n s at ~ o ~ 5 9 ° . T h e i n c r e a s e o f i n t e n s i t y here agrees w i t h the s i m u l t a n e o u s soft p a r t i c l e m e a s urements o n b o a r d the s a t e l l i t e . T h e c o m p a r i s o n s of the e m i s s i o n s a l l o w one to o u t l i n e o i f f e r e n t zones i n the p o l a r o v a l r e g i o n . L e t us n o w l o o k at the s t r u c t u r e of the a t m o s p h e r e i n the 6300 A line in Fig. 5 at the same time. ~esides the t r o p i c a l arc ( i n this c a s e - o n e w h i c h is p r a c t i c a l l y s i t u a t e d o n the g e o m a g n e t i c e q u a t o r ) , the S o u t h o v a l p o s i t i o n is well o u t l i n e d . T h e fine s t r u c t u r e o f the o v a l , u s i n g the d a t a w i t h o u t a v e r a g i n g is s h o w n i n Fig. 6 . T h e p i c t u r e g i v e n there is o n l y the area s i t u a t e d b e t w e e n 67 and 70 deg. inv. l a t i t u d e i n F i g 5 and i t c o i n c i d e s w i t h the m a x i m a l i n t e n s i t i e s i n F i g 4 . 1 t is e v i d e n t that in the oval there are s e p a r a t e r e g i o n s w i t h g r e a t i n t e n s i t y differences.Probably, they are r e l a t e d to the e l e c t r o jet s t r u c t u r e at that time L15] ,but for s t u d y i n g this p h e n o m e n o n we need g r o u n d b a s e d m a g n e t o m e t e r data.
118
M. Gogoshev e t a l .
Q: Q:
Q::
"~
~g&gg V ' , AA
I]U gla.I
iiI!!!II !!!!!!!! Fig. 3
The
16300
imager
picture,obtained
on
213
orbit
orb N~ 2 0 3 21.08.1981
I K- B U L G A R I A - 130 0
EMO-5 I
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10 4
i 10 3
10 2
.
.
.
.
.
.
.
.
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10 1 21:23 21:25 21'27 21:29 21:31 21:33 21:35 21:37 21:39 UI 31,5 34,7 3"1,9 41.1 4/..3 h?,£` 50% 53.£. 56£. 59,3 62,3 65,2 68,0 70,9 73,8 ?6,6 79,.?. Ao 1,55 1,66 1,63 1,67 1,72 1,77 1,82 1,89 1,96 2,03 2.12 222 2,3£. 2,A9 2,68 2,91 3,22 T LCK. -29,5 -..T33 -36,7 -3R8 -£.2'5 -£.49 -46,9 - ~ 8 -50,5 -52,2 -53.9 -5E6 -57,4 -59,2 -6l 1 -63,1-65 1 GEOM.LAT
Fig. 4 The intensities an(i h 7320 ~ in polar
of h 6 3 0 0 A, h oval (orbit.No203)
5577 A,
4278 k,
5 4861 ~,
0
0
B
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,J.
) ~r
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I) )
"I"
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~1~35~50
~1:35~0
71:35 =30
~1:35:20
71:35,10
~1~35,00
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0 0
r~ i.J. el-
0
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0
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,b 0
i~. o el"
(~ C~
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BB
>IOOOR
>900R
>?OOR
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BIB >BOOR
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gg > 1 0 0 0 R H
b
"-I < 4 O O R
m > 900R
r~ >600R >700R > 800R
--~ > 5 0 0 R
•-', < 4 0 0 R
.0
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1
120
M. Gogoshev et aZ.
REFERENCES i. 2. 3.
4. 5. 6. 7. 8. 9. 10. ii. 12.
13.
14.
15.
J.C. Gerard, D.N. Anderson, S. Matsushita, J. Geophys. Res. 82, 1126 (1977) . E.J. Weber, J. Buchan, R.H. Eather, J.W.F. Loyd, Large Scale optical Mapping of the Ionosphere. Preprint AFGL-TR-77-02336, 21 Oct. (1977). M. Gogoshev, G. Grechko, K. Serafimov, V. Rumin, Ts. Gogosheva, A., Simonov, Electrophotometric Studies of Equatorial and Tropical Arcs on Board the Salyut-6 Orbital Station. Preprint NoIAF-81-31, IAF Meeting, Rome (1981). E.I. Reed, J.E. Blamont, Space Res. VII, 337 (1967). E.I. Reed, J.E. Blamont, Atlas of OGO-4 Observations of 6300 A nightglow. A set of 19 color maps. Paper TMX-65954. G.S.F. Center. C.D. Anger, T. Fancott, J. McNally, H.S. Kerr, Appl. Opt. i_22, 1753 (1973). G.G. Shepherd, T. Fancott, J. McNally and H.S. Kerr, Appl. Opt. 12, 1767 (1973). G. Shepherd, C. Anger, L° Brace, J. Burrows, W. Heikkila, J. Hoffman, E. Maier, J. Whitteker, Planet. Space Sci. __21, 1819 (1973). G. Shepherd, L.C. Cogger, J.R. Burrows, J. Geophys. Res. 81, 4597 (1976). P.B. Hays, G. Carignan, B.C. Kennedy, G.G. Shepherd, J.C.G~. Walker, Radio Sci. 8, 396 (1973). E. Rogers, D. Nelson, R. Sovage, Science 183, 951 (1974). L.A. Frank, J.D. Craven, K.L. Ackerson, M.R. English, R.H. Eather, R.L. Carovillano, Global Auroral Imaging Instrumentation for the Dynamics Explorer Mission. In Dynamics Explorer, Ed. by R.A. Hoffman, Space Sci. Instrum. 5, (1981). K. Serafimov, I. Kutiev, S. Chapkunov, M. Gogoshev, A. Bochev, TS. Dachev, I. Ivanov, V. Adasko, V. Balebanov, A. Jossifjan, I. Podgorny, N. Sheremetevsky, New Complex for Ionosphere-Magnetosphere Study "Intercosmos Bulgaria 1300". Preprint IAF-81-122, Publ. by Pergamon Press. IAF Congress, Rome, Sept. (1981). N.P. Petkov, A.K. Kuzmin, M.M. Gogoshev, Ts.N. Gogosheva, T.I. Stavrakov, V. Simov, Photometrichna scanirashta sistema EMO-5 za izsledvane globalnoto razpredelenie na opticheskite emissii i structorata na poliarnite siania. Space Res. in Bulgaria 5, 1982, in print. D.D. Wallis, C.D. Anger, J. Geophys. Res. 8__1, 2857 (1976).
Vol.2, No.7, pp.l15-120, 1983 Printed in Great Britain. All rights reserved.
0273-1177/83/070115-06503.00/0 Copyright © COSPAR
A I R G L O W A T M O S P H E R I C IMAGER ON B O A R D THE 'IK-BULGARIA-1300' SATELLITE M. Gogoshev*, N. Petkov*, A. Kuzmin**, Ts. Gogosheva*, St. Spassov* and Iv. Kostadinov* *Central Laboratory for Space Research, Bulgarian Academy of Sciences, Bulgaria **Space Research Institute Academy of Sciences, U.S.S.R. ABSTRACT
T h i s p a p e r s h o w s the p o s s i b i l i t i e s o f the o p t i c a l s c a n n i n g i m a g e r f o r i n v e s t i g a t i o n o f the s t r u c t u r e o f the a u r o r a / , S A R and tropical arcs and in this w a y to s t u d y the p a r t i c l e p r e c i p i t a t i o n , n e u t r a l w i n d s a c r o s s the m a g n e t i c e q u a t o r , d r i f t s , e l e c t r i c f i e l d s a n d the c u r r e n t s y s t e m s i n t h e i o n o s p h e r e . INTRODUCTION T h e m a i n p a r t o f the b a s i c a e r o n o m i c a n d d y n a m i c a l p h e n o m e n a i n the u p p e r a t m o s p h e r e o f the E a r t h and p a r t i c ~ l a r l y of the i o n i z e d p a r t is c o n n e c t e d w i ~ h the i n t e n s i f i c a t i o n o f the o p t i c a l e m i s s i o n s . T h e intensities at m i d and low latitudes are comparatively low and except for hydroxyl and some oxygen emissions in the D and E regions,don't show clear spatial structure. F o r o x y g e n , the s r u c t u r e is c l e a r l y e x p r e s s e d a t h i g h g e o m a g n e t i c latitude a n d i n the r e g i o n o f the g e o m a g n e t i c e q u a t o r . T h e s t r u c t u r e a n d the d y n a m i c s o f the S A R - a r c and o f tile d i s c r e t e a r c s i n the a u r o r a a r e o f c o n s i d e r a b l e interest for the magnetospheric-ionospheric relations.In the l a s t f e w y e a r s i t b e c a m e c l e a r t h a t i n the r e g i o n o f the geomagnetic equator there are discrete optical ionospheric structures (ar~s) ,which huve comparatively h i g h v a l u e s o f the e m i s s i o n s i n the v i s i b l e a n d i n t h e UY p a r t o f the s p e c t r u m [1,2,3] , T h e t r o p i c a l a n d the equatorial arcs which are observed,a~e c l o s e l y r e l a t e d to the e q u a t o r i a l anomaly,transequatorial p l a s m a t r a n s f e r a n d w i t h the e l e c t r o s t a t i c field, g e n e r a t e d i n t h e r e g i o n o f the g e o m a g n e t i c e q u a t o r . A number of satellite experiments h a v e b e e n d e v o t e d to the p r o b l e m o f the structures i n the g l o w i n g a t m o s p h e r i c r e g i o n s a n d o f a u r o r a . 0 n b o a r d 0G0-II there was a scanning optical photometer[4] ,but since the insrum e n t o p t i c a l a x i s w a s d i r e c t e d t o w a r d the h o r i z o n , v e r t i c a l p r o f i l e s w e r e measured,butnot t h e h o r i z o n t a l s p a t i a l s t r u c t u r e o f the a i r g l o w . T h e o b s e r v a t i o n s w i t h O G O - 4 u s e d to p r o d u c e s p a c e m a p s f o r the g l o b a l d i s t r i b u t i o n o f the m a i n o p t i c a l e m i s s i o n s w e r e a n a l o g o u s [5] . Many successful observations of SAR-arcs a n d o f the d i s c r e t e a u r o r a structures a n d o f the c u s p s t r u c t u r e s w e r e m a d e b y the s c a n n i n g p h o t o m e t e r anO b y t h e r e d - ~ i n e p h o t o m e t e r o n b o a r d I S I S - I I . T h e nesolution o f the instruments was 0,4 .VAE--%he i n s t r u m e n t o n b o a r d " A t m o s p h e r i c Explorer" [10] a l s o m a d e i t p o s s i b l e to s t u d y the s t r u c t u r e o f the o p t i cal a t m o s p h e r i c emissions,but essentially in a vertical direction.
[6,7,8,9]
The DMSP-satellite [11] g a v e the p o s s i b i l i t y to o b t a i n n o t o n l y the auroral fine structure,but also a number of different observations and possibilities of comparison with different satellites and ground-based data.A new possibility of investigation o f the d i s c r e t e s t r u c t u r e s and o f the p o l a r o v a l is g i v e n b y D y n a m i c s E x p l o r e r . The global auroral imaging instrument on board DE-A allows a continued observation o f the w h o l e p i c t u r e o f tile p o l a r o v a l i n a n u m b e r o f s p e c tral l i n e s [12] b u t w i t h c o m p a r a t i v e l y low spacialresolution. Further wet11 g a r i a 1300".
describe
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imager
115
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116
M. Gogoshev et aZ.
"IK-BULGARIA
S±tTELLITE
1300"
The satellite "IK-Bulgaria 1300" was launched in a near circular orbit 9 0 5 / 8 2 4 km, i n c l i n a t i o n 82,5 ° on 7-th August, 1981.The main scientific goal i s the i n v e s t i g a t i o n o f the c o m p l i c a t e d n a t u r e o f m a g n e t e s p h e r i c - i o n o s p b e r ic p h e n o m e n a and r e l a t i o n s . F o r t h i s p u r p o s e the f o l l o w i n g p a r a m e t e r s are measured on board:Thermal plasma,electric fields,magnetic field,electron ar~i p r o t o n s p e c t r u m i n the r a n g e o f 2 0 0 e v to IMev, d r i f t , a n d o p t i c a l g l o w in a large spectral range including UV emissions [13] . F u r t h e r w e ' l l d w e l l in particular o n o n e o f the o p t i c a l i n s t r u m e n t s o n b o a r d - t h e two c h a n n e l scanning photometer E M O - 5 w h i c h w o r k s i n the v i s i b l e p a r t o f s p e c t r u m . B o t h o p t i c a l c h a n n e l s o f the i n s t r u m e n t l o o k to the n a d i r ( t h e s a t e l l i t e is three axis stabilized with an accuracy of stabilization b e t t e r t h a n - + I°). The channels have 8 interference f i l t e r s to m e a s u r e the i n t e n s i t i e s o f the following optical emissions i n the s u b s a t e l l i t e region: ~ 6300 A (0I),
5577 X ( O I )
9
.~
4
278 A Neg.N +o ) , " (I
~ 4861 X (H ~ )
A 7320 k(O I I )
a n d i n the l i n e A 6345 A by w h i c h ~ t h e s p e c t r a l buckgrouncl is d e t e r m i n e d . A t the s e v e n t h and the e i g h t h p o s i t i o n o f the w h e e l are m e a s u r e d the d a r k c u r r e n t a n d the i n t e n s i t y o f the r a d i o a c t i v e s o ~ r c e . T h e w h e e l w i t h the f i l t e r s m a k e s a f u l l r e v o l u t i o n e v e r y 16 s e e . T h e n e c e s s a r y time f o r m e a s u r e ment i n e a c h p o s i t i o n is 1 , S s e c . O n e m i c r o c o o l e r (Peltier effect)gives the possibility to l o w e r the p h o t o m u l t i p l i e r t e m p e r a t u r e to 35 ~ b e l o w t h e t e m p e r a t u r e o f the case. T h e o p t i c a l p r o t e c t i o n o f the c n a n n a l is a c h i e v e d b y a s h u t t e r . T h e i n s t r u m e n t is d e s c r i b e d i n m o r e d e t a i l i n [141 . 6300
A
SCANNING
IMt%GER
I n the s e c o n d o p t i c a l c h a n n e l o f the i n s t r u m e n t E M 0 - 5 is a n i n t e r f e r e n c e f i l t e r p e a k e d at ~ 6 3 0 5 A w i t h b a n d w i d t h 15 A, ~ =40%,and a scanning optical system.The s c a n n i n g is p e r p e n d i c u l a r to t h e m a X s a t e l l i t e m o t i o n . T h e o p t i c a l s c h e m e o f t h e i m a g e r is s h o w n i n F i g . 1.The i n s t r u m e n t a l field of
HO TOR
Fig. I
The
optical
scheme
of
the
scanning
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o
v i e w is 3 . A f t e r h t h e o p t i c a l b a f f l e w i t h a c o e f f i c i e n t o f a t t e n u a t i o n b e t t e r t h a n 5. 10- is a n e n t r a n c e p l a n e m i r r o r , ib/ m o v i n g t h i s s c a n n i n g m i r ror, the o p t i c a l a x i s , w h i c h i S o r i e n t e d t o t h e n a d i r , c a n b e m o v e d to + 15 ° . T h e b,lock s c h e m e f o r the s c a n n i n g m i r r o r c o n t r o l is s h o w n i n F ig. 2 . A v a c u u m stepping m o t o r and w o r m d r i v e is u s e d . 0 n e s i n g l e s c a n o f tlle i n s t r u m e n t (from-15 to +15 °) is m a d e i n I sec. T h e m o t i o n o f the m i r r o r is c o n t i n u o u s w i t h m a r k e r s at s e v e n d i f f e r e n t p o s i t i o n s . W h e n the c o m p a r a t o r f o r a l o g i c a l and o p t i c a l p r o t e c t i o n g i v e s a s i g n a l , t h e s c a n n i n g m i r r o r is a u t o m a t i c a l l y f i x e d at a m i d d l e p o s i t i o n ( l o o k i n g to the n a d i r ) . T h e l o g i c o f the motion control besides the program, can also mand f o r s w i t c h i n g on and s w i t c h i n g off.
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i n a n o r m a l mode o f o p e r a t i o n one s i n g l e s c a n c o n t a i n s 7 pJxels. The p i x e l dimensions at the l e v e l o f F m a x ( w e assume 270 km) are 8x52 k m . T h e f i r s t v a l u e is o b t a i n e d by some o v e r l a p o f the f i e l d of v i e w in the d i r e c t i o n of s a t e l l i t e m o % i o n . l n this w a y we h a v e a b e t t e r o p p o r t u n i t y to i n v e s t i g a t e zo n a l strttctures. T h e t h r e s h o l d s e n s i v i t y o f the w h e n the i n s t r u m e n t p r o t e c t i o n
c h a n n a l is 50 R, and the u p p e r c i r c u i t y is a c t i v a t e d .
limit-120kR,
DATA ANALYSIS A map of i n t e n s i t y d i s t r i b u t i o n s , t a k e n by the s c a n n i n g i m a g e r o n b o a r d " I K - ~ u l g a r i a 1300" on A u g u s t 1 9 8 1 , o r b i t 213 is s h o w n in Fig. 3 . T h e i n t e n s i t y d i s t r i b u t i o n of I ~ ^ _ ^ is s h o w n i n 5 d i s c r e t e l e v e l s w i t h 100 R, 100-150 R, 150-200 R, 2 0 0 - 3 0 0 - 3 u u R . a n d more t h a n 300 R . T h e r e g i o n s of the N o r t h tropical a ~ c ( ~ ~ 5 ° , A @ ~ 1 8 O) a n d o f t h e S o u t h t r o p i c a l arc (qgeo~r. 7 , J[@=24 ge°gr" ) are well o u t l i n e d . T h e m a x i m u m i n t e n s i t i e s i n the n o r t h e r n arc e x c e e d 200 R and i n the S o u t h they are a b o u t 150 R.We must n o t e that o n the p i c t u r e 15 s c a n a v a r a g l n g is used. I n the l o w e r p a r t o f the figure the i n t e n s i t y i n c r e a s e is r e l a t e d w i t h the s a t e l l i t e a p p r o a c h to the s u n l i t a t m o s p h e r e . O n the o t h e r o r b i t s the t y p i c a l level for A p p e l t o n l s a i r g l o w a n o m a l y ( t r o p i c a l arcs) i n 6 3 0 0 ~ is o b v i o u s . Some d a t a s h o w the a s s y m e t r y in the a r c s , p r o b a b l y r e l a t e d w i t h the i n f l u e n c e o f n e u t r a l w i n d s and d r i f t s . ~ h e 6 3 0 0 A S c a n n e r I m a g e r p o s s i b i l i t i e s , c a n be i l l u s t r a t e d by Fig. 4 r e f e r r e d to o r b i t N o . 2 0 3 ( 21 A u g u s t , 1 9 8 1 ) . H e r e are s h o w n the m e a s u r e d i n t e n s i t i e s f r o m the f i r s t c h a n n e l w i t h the b a c k g r o u n d f r o m the s i x t h c h a n n e l r e m o v e d . T h e d i f f u s e a u r o r a l r e g i o n b e g i n s at ~ o ~ 5 9 ° . T h e i n c r e a s e o f i n t e n s i t y here agrees w i t h the s i m u l t a n e o u s soft p a r t i c l e m e a s urements o n b o a r d the s a t e l l i t e . T h e c o m p a r i s o n s of the e m i s s i o n s a l l o w one to o u t l i n e o i f f e r e n t zones i n the p o l a r o v a l r e g i o n . L e t us n o w l o o k at the s t r u c t u r e of the a t m o s p h e r e i n the 6300 A line in Fig. 5 at the same time. ~esides the t r o p i c a l arc ( i n this c a s e - o n e w h i c h is p r a c t i c a l l y s i t u a t e d o n the g e o m a g n e t i c e q u a t o r ) , the S o u t h o v a l p o s i t i o n is well o u t l i n e d . T h e fine s t r u c t u r e o f the o v a l , u s i n g the d a t a w i t h o u t a v e r a g i n g is s h o w n i n Fig. 6 . T h e p i c t u r e g i v e n there is o n l y the area s i t u a t e d b e t w e e n 67 and 70 deg. inv. l a t i t u d e i n F i g 5 and i t c o i n c i d e s w i t h the m a x i m a l i n t e n s i t i e s i n F i g 4 . 1 t is e v i d e n t that in the oval there are s e p a r a t e r e g i o n s w i t h g r e a t i n t e n s i t y differences.Probably, they are r e l a t e d to the e l e c t r o jet s t r u c t u r e at that time L15] ,but for s t u d y i n g this p h e n o m e n o n we need g r o u n d b a s e d m a g n e t o m e t e r data.
118
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Q: Q:
Q::
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iiI!!!II !!!!!!!! Fig. 3
The
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Fig. 4 The intensities an(i h 7320 ~ in polar
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M. Gogoshev et aZ.
REFERENCES i. 2. 3.
4. 5. 6. 7. 8. 9. 10. ii. 12.
13.
14.
15.
J.C. Gerard, D.N. Anderson, S. Matsushita, J. Geophys. Res. 82, 1126 (1977) . E.J. Weber, J. Buchan, R.H. Eather, J.W.F. Loyd, Large Scale optical Mapping of the Ionosphere. Preprint AFGL-TR-77-02336, 21 Oct. (1977). M. Gogoshev, G. Grechko, K. Serafimov, V. Rumin, Ts. Gogosheva, A., Simonov, Electrophotometric Studies of Equatorial and Tropical Arcs on Board the Salyut-6 Orbital Station. Preprint NoIAF-81-31, IAF Meeting, Rome (1981). E.I. Reed, J.E. Blamont, Space Res. VII, 337 (1967). E.I. Reed, J.E. Blamont, Atlas of OGO-4 Observations of 6300 A nightglow. A set of 19 color maps. Paper TMX-65954. G.S.F. Center. C.D. Anger, T. Fancott, J. McNally, H.S. Kerr, Appl. Opt. i_22, 1753 (1973). G.G. Shepherd, T. Fancott, J. McNally and H.S. Kerr, Appl. Opt. 12, 1767 (1973). G. Shepherd, C. Anger, L° Brace, J. Burrows, W. Heikkila, J. Hoffman, E. Maier, J. Whitteker, Planet. Space Sci. __21, 1819 (1973). G. Shepherd, L.C. Cogger, J.R. Burrows, J. Geophys. Res. 81, 4597 (1976). P.B. Hays, G. Carignan, B.C. Kennedy, G.G. Shepherd, J.C.G~. Walker, Radio Sci. 8, 396 (1973). E. Rogers, D. Nelson, R. Sovage, Science 183, 951 (1974). L.A. Frank, J.D. Craven, K.L. Ackerson, M.R. English, R.H. Eather, R.L. Carovillano, Global Auroral Imaging Instrumentation for the Dynamics Explorer Mission. In Dynamics Explorer, Ed. by R.A. Hoffman, Space Sci. Instrum. 5, (1981). K. Serafimov, I. Kutiev, S. Chapkunov, M. Gogoshev, A. Bochev, TS. Dachev, I. Ivanov, V. Adasko, V. Balebanov, A. Jossifjan, I. Podgorny, N. Sheremetevsky, New Complex for Ionosphere-Magnetosphere Study "Intercosmos Bulgaria 1300". Preprint IAF-81-122, Publ. by Pergamon Press. IAF Congress, Rome, Sept. (1981). N.P. Petkov, A.K. Kuzmin, M.M. Gogoshev, Ts.N. Gogosheva, T.I. Stavrakov, V. Simov, Photometrichna scanirashta sistema EMO-5 za izsledvane globalnoto razpredelenie na opticheskite emissii i structorata na poliarnite siania. Space Res. in Bulgaria 5, 1982, in print. D.D. Wallis, C.D. Anger, J. Geophys. Res. 8__1, 2857 (1976).