Type pi2 geomagnetic pulsations and Alfven wave resonance on night side of magnetospher

Kazak, B. N.

Koshelevskiy, V. K.

Lizunkova, I. S.

Raspopov, O. M.

Shlish, R.

Troitskaya, V. A.

English

NASA Technical Reports Server

Nat i o m l  .Aeronautics and Space Administration 
( ;oddad Space Flight (kntcr 
Contract No.NAS-5-12487 
ST - (;M - 10675 
INVESTICATION OF TYPE-Pi2 GEOMAGNETIC PULSATIONS 
AT MAGNETOCONJUGATE POINTS 
0. M. Kaspopov 
V. A. Troitskaya 
R. Shlish 
I. S. Lizunkova 
V. N. Kazak 
?I. K. Ksshelevskiy 
(USSR) 
t 
,i' , 
0 
23 FEBRUARY 1968 
https://ntrs.nasa.gov/search.jsp?R=19680007098 2020-03-12T09:21:19+00:00Z
I 
(*> 
1)oklady A.N. SSSR, 
(kof iz i ka 
'lorn 178, No.1, 
str. 93 I U U ,  
Tzdatcl 'stvo "N4U?LA", 
MOShVA, 1968 g. 
SUMMARY 
by 0. M. Raspopov 
V. A .  Troitskayn 
R. Shlish 
I .  S. Lizunkova 
B. N. Kazak 
V. K. Koshclevskiy 
A~ialys is of the behavior of Pi2-pulsations at Sogra and Kerguelen shows 
that it is similar at both conjugate points. 
ration mechanism of Pi2-pulsations proposed in 1967 by Raspopov [ 4 ] ,  who explain- 
ed it by the resonance of Alfven waves on the night side of the magnetosphere, 
in the tube of force directly adjacent to the beginning of the neutral layer. 
This speaks in favor of the gene- 
* 
* * 
1. A joint registration of geomagnetic field pulsations at magneto- 
conjugate points Sogra (58" N.lat., 122" E.long.) and Kerguelen (58" S.lat. 
124"  l;.long.) began in September 1964 after a microvariation station was in- 
stalled at Sogra. This station was of Leningrad University's Bryunelli system. 
A t  Kerguelen the registration of pulsations was conducted by means of a 
fluxmeter-type device of Zel'ser's construction. 
19b6 was also a microvariation station of Leningrad University, which permitted 
t o  conduct additionally a session of 
on a device having identical parameters. 
Installed there in February 
simultaneous registration of pulsations 
For the investigation of type-Pi2 pulsations two observation periods were 
chosen: from 18 October to 16 November 1965 and from 4 February to 15 March 
1966, which allowed us to compare the material obtained at conjugate points 
on a diversified and identical apparatus. 
2. For the two observation periods 176 cases of Pi2-pulsations were ana- 
A good agreement took place in an overwhelming number of cases bet- 
lyzed, of which the oscillation periods varied within the limits from 40 to 
180 sec.  
ween the shape of trains of Pi2 at Sogra and Kerguelen (Fig.1) In trains where 
superimpositions of smaller-period oscillations were absent, the accuracy in 
the coincidence of extreme values of oscillation amplitude and, consequently, 
of their period, may be estimated at 2 to 3 seconds, which coincides with the 
precision of time readings from magnetogrms . 
(*) 
NYKIl TOUiKN(I1. 
ISSLEWVANIYE GEWIGNITNYKH PUL'SATSIY T I P A  Pi2 V b%WNITPSOPRYAZHEN- 
I:or ;I mort\ complcx configurat ion o f  osci 1 l a t i ons  the  prec is ion  drops 
t o  5- 10 seconds, which is explained by d i f f e rences  i n  thc  l~ehav io r  a t  con- 
juga te  poin ts  of pu lsa t ions  coi is t i tut i i ig  the  type-Pi2 rnisr-ostructure. 
Sogra 
2200 
Kc. rgue 1 en 
2200 hrs  i h r i n g  the second period of 
observat ions the  mean amp1 i tudc 
r a t i o  a = Aqs / Ak: of Pi?-pul.;a- 
t ions was fourid t o  equal t o  1 . 0  
f o r  110 t h  Iio r i  zont n l  co~riponcnt T
of t h e  geomagnetic f i e l d .  During 
23 H 196G 2. 
Fig.  1 
A&/;- 
Fig. 2 
the f-irst observat ion per iod only the  'mplitudc r a t i o  i n  t h e  11-componcnt \cas 
f'ound t o  IIC equal t o  the  uni ty ;  i t  was 0 . 9  l o r  the 1)-componcnt. ' h e  root-mean 
square valucs  of the  devia t ions  A u / a  I'rom average values fo r  both components 
d id  not  excccd 10 percent  i n  1963 arid 1966. 
The cha rac t e r  of the  s c a t t e r i n g  of the  quan t i ty  Aa /a f o r  t he  second ol)sei-- 
vat ioi i  per iod is represcnted i n  Fig.2.  As may be seen,  the  mean runplitucle r a t i o  
of* thc I)-coinponent i n  1964 depar t  from the  un i ty  by a quant i ty  a l s o  l!ving within 
the hounds of e r r o r s  i n  the  f i n a l  r e s u l t s .  I t  is poss ib le  t h a t  the not iccd phc- 
~ i o ~ n c ~ i o ~ i  s the  r e s u l t  of systematic e r r o r s  during ohservat ions of pu lsn t  ions 1))- 
d i v e r s i f i e d  apparatus  ;It two s t a t i o n s .  
prcvalcnce of P i 2  amplitude i n  Kerguelen i n  October-Novcml~cr 1963 is  the  r e s u l t  
of t h e  seasonal  course of t h i s  pu lsa t ion  parameter. 
I t  is  not excluded, howver ,  t h a t  tlic 
I t  should be remarked t h a t  i n  a s e r i e s  of cases  of PiZ-generation a suhstan- 
t in1 irifluencc on the  value of the amplitude r a t i o  of  separa te  components a t  
conjugate  poin ts  was exer ted  by t h e  v a r i a t i o n  i n  t h e  po la r i za t ion  d i r e c t i o n  of  
osc i l l r i t io i i s  i n  Sobra mid Kerguelen. 
hrialysis of p o l a r i z a t i o n  of P i2 -osc i l l a t ions  has shown t h a t  the  s ign  of 
o s c i  l l a t i o n s  of the  11-component a t  magnetoconjugate po in t s  i s  i d e n t i c a l .  'The 
s i g n  of  the  1)-coinponent is d i f f e r e n t  i n  the  northern and southern hemispheres. 
111 view of s ign i  f icnnt  d i f  fercnces i n  the  frequency chc i rac te r i s t ics  
o f  thc  ;ipparatus u t i l i z e d  during t h e  f i r s t  period of ohservntioiis,  the  ro-  
t a t i o n  d i r e c t i o n  of t h e  magnetic f i e l d  vec tor  was determined only from 
iii'igpctogi*aIiis obtained i n  i960. 
1 0 2  P i 2  t r a i n . ;  were e u z ~ i n e d .  Ir? 2 7  c;:stts thc  ro ta t io i i  d i r e c t i o n  cuuid 
not  he re1 iably determined because of the  complex charac te r  of- o s c i l l a t i o n s  
or  i n  view of  t h e i r  l i n e a r  po la r i za t ion .  
magrictic f i e l d  vec tor  a t  conjugate po in t s  were fcund t o  be opposi te  i n  72 
cases. For  3 t ra ins  t ! ~  r o t a t i e n  d i r e c t i o n s  of t he  ;-i.;tor iolncicled i l l  both 
hemispheres. A l l  cases  of P i 2  w i t h  uiomalous charac te r  of  vec tor  r o t a t i o n  
were r e g i s t e r e d  on 11 February 1900 from 0025 t o  0150 hours. 
trails subq tan t i a l  d i f f e rences  %ere noted i n  the  m y i i t u d e  of o s c i l l a t i o n s  
a t  conjugate po in t s :  t he  Pi2's amplitude a t  Kerguelen was about 1 . 7  times 
higher than a t  Sogra. 
The r o t a t i o n  d i r e c t i o n s  of the  
For these  
3 .  From the  ana lys i s  of the behavior of Pi:-pulsations a t  Sogra and 
Kierguclen the  conclusion may be derivcd t h a t  the  behavior of  pu lsa t ions  of 
t h i s  type is similar a t  both conjugate po in t s .  They a r e  synchronously es- 
c i t e d  i n  the  nor ther  and southern hemispheres, and t!ieir shape, per iod and 
amplitude are i n  good agreement. 
opposite i n  both hemispheres. 
vec to r  is c h a r a c t e r i s t i c  
harmonics of s tanding AlfvGn waves. 
The s ign  coincidence of 11-components is 
'The r o t a t i o n  d i r e c t i o n  of the  magnetic f i e l d  
of the  e x c i t a t i o n  i n  the  magnetosphere of even 
Simi la r  behavior of  Pi2-pulsat ions a t  magnetoconjugate po in t s  speaks 
in  fai-or of the  generat ion mechanism of P i2-pulsa t ions  proposed i n  r e f .  [-I]. 
According t o  the  l a t t e r ,  the  generat ion of Pi2 is  explained by the  resonance 
of Alfv6n waves on the  n igh t  s ide  of the  magnetosphere, i n  the  tube of force  
d i r e c t l y  ad jacent  t o  t h e  beginning of the  neu t r a l  l aye r .  Owing t o  the  c lose -  
. - % d Y  ~ F J C C  e!- the n e u t r d  ?z;zr zii A?f;;&l velocity miiii i i i imi t d e s  piace  i n  the  equa- 
t o r i a l  plane,  which leads t o  the  subdiv is ion  of  the  magnetosphere i n  two sym- 
metrical p a r t s .  That is why t h e  cha rac t e r  of pu l sa t ions '  p o l a r i z a t i o n  a t  con- 
.jugate po in t s  will corrcspond t o  the  behavior of the  second harmonic of illfvdn 
waves, while the  per iods and amplitudes of o s c i l l a t i o n s  must about mutually 
co inc  i de. 
i n s t i t u t e  of Ea r th ' s  Physics i n  the 
name of 0 .  W. SCIIMIIIT 
of t h e  USSR Academy of Sciences.  
Icningrad 1Jnives i t y  in the  name of 
A.  A. Zhdanov 
The P a r i s  l lnivers i ty  
Flanuscript received 
on 9 March 1967 
3 
R I F E I< E N C E S 
[ I  j . S .  1'. RPJGd,:NSKIY, I:. E. ER'r'iuXTLLI , Tu'. 1 : .  k7Ui'EVIU~. Inform. B y u l l .  
MGC; ( Inf .  Hullctin I G Y )  , No.:, AN SSSR, 65, 1959. 
121. 13. N .  KAZAK, 0. PIl. MSPOPOV. Geofizichcskoye priborostroyeriie, 2b, 1965. 
[ 3 J .  M. SUGIUKA, C .  K. WILSON. J. Geophys Kes. W, 1211 ,  1964. 
[ 4 1 .  0. M. R4SpOPOV. Tezisy dokl .  ila Vsesoyuznoy konferentsii po itogam MGSS 
('Ifieses reported t o  t h e  All-Union Con€. on Results of the 
19b7 
CONlIUCT NO.  NAS - 5 - 124 8 7 
VOLT 'I'IKI INICAL COKI'ORKI'ION 
WAS1 ITNG'I'ON 1 ) .  C . 20036. 
Tclcphone : 2 2  3-  6700 (X-  3 6 )  
1145 - 19th  S t .  NW 
Translated by ANLIFE L. BRICIIAN?' 
at home on 22 February 1968 


Investigation of type-pi 2 geomagnetic pulsations at magnetoconjugate points

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