Shorter Contributigns

Pea~oMe

I IO[ IOH{EIIHf I 17 IA[ IEOMAI ' t lHTI Ib IX IIO.~IOCOB H C C a E ~ O B A t I H B I E ~ J I / t q E X O C ~ r I O B A ~ H H X F O P I I M X

H O P O ~ ~OHEMBPH17ICHOFO tl 1- [AJIEO30~fC[(OFO B O 3 P A C T A

(Ilpe~BaplTweJ1~uoe cooSmem~e)

VkCLA.V BucIIA FeogSu.~uuec~tt~ u~cmumym tI CAH, Hpaza

[<pNBall llepeMeuteH~i~l IIO.rIIOCOB 6bigIn ite(:~e2~oBaHa Ha OClIOBaHIIII lI3.~iepel~gg 'IIa,qoO- MaI'HHTHMX xapaKTeptiCT}~K A()I{C.',t6prlftcNttx H rlaneo3oficir nopo~ B pafioHe I ;appaH~mna. ~aN liONa3aHo (plfc. l), no,~oa{emi~I no=IvOCOB o6pa3ylOT OTHOCtITe.qBHO HenpepuBHylO I~pa- Byte n xpouo,'Ior~ec~o,~1 imp~IaRe, KOTOpa~I Han~maere~I RmI Jlone.~6prt~Icm.tx nopo,x n o6- .~[a(-x~ cpe;~Heii A,~,epnKn ~ npo:toaa~aeTca n IO-B rianpam~cInUt (~e.~t6pHfi) ,tepea mvm(yio A~pm~y, iI}1;I~m (op;xom~) ~i 14H.xoHe3~lm. 3;~eeI, oHa nonopaunBaeTea ~ ce~epy ~ r(po- xoaur uepea Pinoim~ }I BOCTOqttylo qac'rh Cr~6~prl (Nap6oH, riep~t~), l-laaeo,~mrm~Trl~e }Iec.ae.~oBamt~1, n tlaC.THOCTtI ~(e.~6p~fic~nx r~ op~oB}v~e(;N~x ropHh~X nopoa noxwr~ep~.~atoT ~[BI~H~eIIIIO iloo"lIoca rio KpttBofl OT 3orla2Ia K BOCTONy tI erlOCO6eTnylOT 06'bflCHeIllilO O0:IMHOFO pa;r cylllecTBytoillero rToit.a eme B t,.mponh~x na.aeoMarrt~Tm,~x galiHiaX Me;n,~y nepHo- jLaHH /IoKe.~t6pH~I ~I ,~eBotla. I.I3 epamteHITn rlaneo~tarHtiTHhtx ;latiHhlX n EBpone a AMept.iiio 6r~ran cae.-mm,~ Her-:OTOphIe ~{omae aar~,a}o*toHrrn o RBrTme}rllrl o6(mx I{OIITIIHOHTOB.

Hoc'rym~:ro 9. 12. 1960

SOME T Y P E S OF G E O M A G N E T I C P U L S A T I O N S S T U D I E D AT T H E F A S T - R E C O R D I N G O B S E R V A T O R Y B U D K O V W I T H AN I N D U C T I V E M A G N E T O M E T E R

l~r ,r!yl f 1r KONESN~" Geophysical Institute, Czechosl. Acad. Sci., Prague*)

Oscillations of d i f ferent frequencies are superposod on long periodic changes in the geomagzmtie field. Oscillations hav ing a per iod shor te r t h a n a few h u n d r e d seconds wi th an ampl i tude of the order of 10 -7 to 10 -~ Oe have been called pulsa t ions . Due to m u t u a l differences and the n u m b e r of years in which classif icat ion has no t been c!ear, the 10th Corrmfittee of IAGA called for the series of pulsa t ions last ing several hours and h av i n g an ampl i tude of the or(fer of 0.1 y to be known as Pc pulsa t ions (Fig. 1) and those of l imi ted dura t ion (usually shor te r t han one hour), w i th an ampl i tude of a few t en t h s of y and of ten accompany ing bay-d is tu rbances , as P t ' pu t s a t i ons (Fig. 2).

The s tut ty of both Pc and Pt pulsation~ is subjec t to sui table ins t rumenta l equipment . of the observatory . Due to the shor t per iod .and small ampl i tude of the pulsa t ions s t a n d a r d var iometers , the ser~sitivity of which rarely exceeds 1 y/ram, eanno~ always be success-

6/,13,,, 6 ~,24 ~,,

Fig. i . 2. 4. 1959, 06 h 13 m--06h 24n G. M. T. (Pc)

*) Address: Bo6ni II , P r a h a 4 - - Spof'ilov.

Studia geoph, et geod. S (1961) 073

]~ pam~:ue cooSutettun

ful ly used for the i r recording. The re are m a n y m e a s u r i n g i n s t r u m e n t s w h i c h p e r m i t re- l iable recording of geomagne t i c pu l sa t ions . Accord ing to t he i r c o n s t r u c t i o n t h e y m a y be d iv ided in to two basic groups: i. a p p a r a t u s w i th classieM m a g n e t o m e t e r s , whe re t he mag-aet is suspended on a f ibre or b a l a n c e d on a cu t t i ng edge, 2. a p p a r a t u s w h i c h t r a n s f o r m s changes in t he magne t i c f ield to changes in electr ic cur ren t . The m o s t f r e q u e n t l y used of the l a t t e r g roup is ~he i n d u c t i v e m a g n e t n m e t e r , which consis ts of a coil a n d ga lvano-

20~9" 21~ ; -

Fig. 2. 5. II. 1959, 20h58-5m--21h00m G. M. T. (Pt)

meter . The coil axis is o r i e n t e d in to t he d i rec t ion of the g e o m a g n e t i c f ie ld e l emen t be ing measured . The f l u c t u a t i o n s in i ts i n t ens i ty are caused b y c h a n g e s in the magne t i c f lux t h r o u g h t, he sur face of the coil, t h u s induc ing in t h e coil a n eros e = -- de~dr . The c u r r e n t p r o p o r t i o n a l to these changes t h e n f lows t h r o u g h t he g a l v a n o m e t e r connec t ed to i t s t e rmi - nals.

An flnductive m a g n e t o m e t e r was bu i l t in 1958 in the Geophys ica l I n s t i t u t e of CAS for s t u d y i n g r ap id t i m e changes in the Z c o m p o n e n t ot the geomagne t ic f i e ld w i t h a sensi- t i v i t y of the order of 10 -2 y /see / ram; th i s i n s t r u m e n t was p u t into p e r m a n e n t ope ra t i on a t the geomagne t ic o b s e r v a t o r y B u d k o v f rom I. 1. 1959. The coil, d = 16 m in d i ame te r , is m a d e of an i n su l a t ed copper cable, a n d has 42 t u rns a n d a t o t a l r e s i s t a n c e of 25[L I t is p laced ho r i zon ta l l y in to a c i rcular e x c a v a t i o n a t an average dept.h of 80 em below t h e surface. The course of the t ime changes is reeorded op t ica l ly wi th a g a l v a n o m e t e r on pho~ographic paper , which is m o v e d a t 15 m m / m i n . The record ing speed was chosen so t h a t the t a n g e n t to the inf lec t ion p o i n t of th~ curve, cor responding to t h e course of t he p u l s a t i o n s w i t h the m o s t f r e q u e n t l y occur r ing f requency*) , enclosed an a n g l e of approx i - m a t e l y 120 ~ w i th i ts successive axis. W h e n the def lec t ions of the t a n g e n t f r o m th i s angle are large the recorded p h e n o m e n is e i the r too dense or e longated , in b o t h eases the r e su l t be ing ind is t ine t . W i t h reeord ing e q u i p m e n t where the cy l inder is sh i f t ed u n i f o r m l y in the d i rec t ion o[ the r o t a t i n g axis, a suff ic ient d i s t ance be tween the curves denot, ing t he course m u s t be chosen to p r e v e n t t h e i r over lapp ing . L e t us now r e t u r n to the d i f f e r e n t t ypes of pu l sa t ions recorded w i th a n i n d u c t i v e m a g n e t o m e t e r f rom I. 1. I959 to 30. 9. 1930 a t t h e B u d k o v obse rva to ry .

P c T Y P E P U L S A T I O N S

This t ype of pu l sa t ions is c h a r a c t e r i z e d b y i ts re la t ive ly long d u r a t i o n ( severa l hours) w i th the maximLun of occurrence in the d a y t i m e . A m o n g these regular p u l s a t i o n s we found, pa r t i cu l a r l y in the a f t e rnoon , pu l sa t i ons w i th a per iod usua l ly b e t w e e n 20 a n d 40 sec, wh ich can be d iv ided in to dist. inet g roups . P u l s a t i o n s in those g r o u p s of w h i c h t he

71 / ' 23 " ' 17 ~ '28 "~'

Fig. 3. 20. 7. 1959, 11 h 23 m - - l [ h 28 m G. M. T. (P% beating pulsations)

pe r iod is m o s t f r e q u e n t l y 4 - - 5 mia . h a v e been called bea t i ng p u l s a t i o n s P % (Fig. 3). The i r cha rac te r i s t i c f ea tu re is t he g r adua l increase in the a m p l i t u d e of t he oscilla- t ions in t he b e a t up to a m a x i m u m , a f t e r wh ich it g radua l ly decreases again . These groups are r epea t ed in ce r t a in t h n e in te rva l s , o f ten a f t e r a per iod of seve ra l hours .

*) A t B u d k o v observatory. . / --~ 0"03 -- 0-05 Hz.

O7,~ Studia geoph, e t g e e d . 5 ~1961)

Shorter Contribution.~

Our a t t en t i on was a r res ted by a nm~nber of e~xceptions to this rule. Cases were fo tmd in which the ampl i tude cIid no t gradual ly increase to a rnaximtun; af ter the initial c o n s t a n t course which last, ed 1 -- 2 minutes , there was a re la t ive ly abrupt increase to the m a x i m u m , af ter which the ampl i tude gradual ly decreased (Fig. 4). A large a m o u n t of record ing mater ia l was sub jec ted to a careful analysis bu t only a small n u m b e r of such p h e n o m e n a were fmmd so tha t t, heir possible dependences canno~ ye t be sa t is factor i ly d e t e r m i n e d .

A no the r interest.ing p h e n o m e n o n was found on the records e. g. of 6.9. 1959, 18.9. i959 or 21. 1. 1960. I t is seen f rom these records t h a t the regular course of the _Pc pu l sa t ions

- I I I 13 ~'23

Fig. 4. 16. 9. 1959, 13 h 19 m - - 13 h 23 m G. M. T. ( "ha l f -bea t " pulsa t ions)

tOh32" 7o~36

Fig. 5a. 6. 9. 1959, 10 h 32 m - - 10 h 36 m G. M. T. (superposirion)

t,,.// iTs'f6 ~

,& Fig. 5b. 21. 1. 1960, 11 h 16 m - - l l h 19 m G. M. T. (superposit ion)

v

0 7 ~' 7 G "

Fig. 5e. 18. 9. 1960, 07 h 13 m - - 0 7 h 16 m G. M. T. (superposi t ion)

Studia geoph, et geod . 5 (1961) 275

l~ pam/z ue coodufettu.ct

is i n t e r r u p t e d in some in te rva l s b y osci l la t ions which in t h e i r a m p l i t u d e a n d pe r iod do n o t be long to t he basic course. The resul~an~ sl~ape of the curves ind ica tes t h e supe rpos i t i on of h igher h a r m o n i c s on the basic pu l s a t i on f r e q u e n c y in the d i s t u r b e d i n t e r v a l (Figs. 5a, b, e). This p h e n o m e n o n was recorded exc lus ive ly in the per iod of i n c r e a s e d m a g n e t i c ac t iv i ty .

P t T Y P E P U L S A T I O N S

As was s t a t e d above , th i s type of pu l sa t ions differs f rom the P c p u l s a t i o n s b y its l im i t ed du ra t ion , b y the m a x i m u m of occurrence, wh ich is in the evening , a n d l a s t b u t no t leas t by the course of the in i t i a l a n d d e c a y i n g phase . T he in i t ia l phase is d i s t i n g u i shed in n e a r l y

20~o8"

Fig. 6. 14. 1. 1960, 20 h 08 m - - 2 0 h 09.5 m G. . '~ . T. ( a c c o m p a n y i n g p u l s a t i o n s )

'all eases b y a n exponen t i a l course a n d the decay ing phase by c o n s i d e r a b l e a t t en , l a t i on . Groups of p u l s a t i o n s wi th per iod 2 - - 6 see a n d a m p l i t u d e f l u c t u a t i n g in f r a c t i o n s of T (Fig. 6) can be recorded in the in i t ia l s tage of P t pu l sa t i on (above a c e r t a i n i n t e n s i t y level, wh ich is g iven b y t he sens i t iv i ty of the i n s t r u m e n t s ) wi~h m e a s u r i n g e q u i p m e n t h a v i n g a h igh sens i t iv i ty . T he occurrence of such pu l sa t ions is so f r e q u e n t l y t oge the r w i th the Pt pu l sa t ions t h a t t hey can be r ega rded as pu l sa t ions a c c o m p a n y i n g Pt t y p e s

PULSATIO~N-S "WITI-I PERIOD SHORTER THAN 20 SEC

On 14. 7. and 18. 7. 1960 the B u d k o v obse rva to ry , us ing a sys t em h a v i n g sens i t iv i ty . of the order of 2 . 10 -a -(/see/ram, recorded a n o t h e r type of pu l sa t ions -- p e a r l s -- wh ich are d i s t i ngu i shed by s h a r p changes in the field s t r e n g t h du r ing a shor t t ime i n t e r v a l (Fig. 7, 8).

Fig. 7. 14.7. 1960, 01 h 33 m - - 0 1 h 34 m G. -~[. T. (pearls)

Fig. 8 . 1 8 . 7 . 1960, 0 l h 09 m - - 0 1 h 10 m G. M. T. (pearls)

T h e series of such pu l sa t ions las t only a few hours . F r o m the p r e l i m i n a r y e l a b o r a t i o n it was possible to de t e rmine t he a p p r o x i m a t e l imi t s of the f r equency reg ion : 0 -5 - -2 e/scc, a n d it was also found t h a t the b r o a d r ~ e of a m p l i t u d e s in va lues of 10 --a y f l uc tua t e s a r o u n d t he midd le of the series. Ex~c~ va lues will be de~ermined b y a d e t a i l e d analys is .

Rece ived 15. 11. 1960 Ret, iewer : ,Ft. B~hou,nek

276 Studia genph, et geod. ~ (1961)

Shorter Contributions

Pe3ioMe

t IEHOTOPbIE THI-IL[ FEOMAI'HHTI:[blX IINJIbCA[~HlYl, I-IPOC,,:IEH-~IIBAEMBIX IIPIJ I-IOM01I[H HII~NHII~HOItHOFO

MAFHHTOMETPA B EbICTPOPEFIICTPI/IP,VIO[I~EIt OBCEPBATOPHtl BV;~ HO B

FeogSuau,r uncmumym ~t C:IH, Hpaza

B pa6oTe paee.~taTpltBaeTcg tieciu)dli, No OCOOhtJ( r I'0OM,~IFII[HTIII,I'X Ily.IhCalIIIfI aa-

~erm ' ,rplrpo~aauI, tx B nepp~ma OT 1. 1. 1959 r. 2o 30, 9. 1960 I'. tt o6cepnaTopi~l Fju r llyJii~CLlfItil~l TtIna .,De Ohl.'II~! O(~t[~lpyH~l.~tII,I, BO-llepBblX, lleOt~hItfHOC ' gl~..-leHlle R TetietliIe pc-

rvmxpuoro iipolteeca 6~e~mK nyzrm'~tpv~)mHx P% ~ nO-~Top~,~x - - IIet<oTop~,m ~le~op.~,am~rt n'p,mecca nyna,"am~fi Pc ~ ~mp~mxe IIaablnleitHOft .~arltl~TIIOfl attrlinnocTt~. u i~y:~bcal~fi TtIrla P t oi~paill[aeTt'g BHtIMfllHIe t~a ~m'm.~Hy~O d~aay ~r lly.~cat~m~ TgIla ;}-;e.~lqy~HtIH C nepHo.IOM NoJie(~l~[ilfl HO[JO'le 20 r Itp(L'(t;Tat~JleH],[ Ollpe/le.qellllhlM OTp03Ir tlX xapal{- TeplfCTttqeCl(Ol'O XO,~a II:L',leHOtltl~.

lIocTyHg,'iO 15. 11. [960

?JBER D I E V A g l A T I O N E N DES I O N O S P H ~ 4 R I S C H E N C O N V E g S I O N S K O E F F I Z I E N T E N N A C H

S C H R 2 - ~ O E I N F A L L S M E S S U N G E N IM L A N G W E L L E N B E R E I C H

H. ,xs K o c h , Rt-DOLF SCm~tI.~DF.R Geop]~Iysilcalisches Observatorium Collm des Geoph. Ir~t. d. Karl-Marx.Universit i i t ,

Leipzig*)

I. E I N L E I T U N G

A m Geophys ika l i sehen Observat, o r ium Collm der I~2arl-3farx-Universl t~t Leipzig werden se i t d e m 1. 10. 1957 regelm~Big SehrSgeinfal lsme~sungem auf 245 kHz (Sender K a l u n d - borg) u n d 272 kH z (Semt.er (~eskoaloverisko) durehgeftihrt , . Die Auswahl der Sender h a t t e fo lgende Gri inde: Das O b s e r v a t o r i u m Colhn ver fSgt m i t den S t r eeken K a l u n d b o r g - -Collm u n d ~eskosloven~sko-Collm fiber je ein*~ Nord- u n d eine Sfidstreeke, so dal3 zonale Un te r seh iedo in den Reg i s t r i e rungen erfaBt werden k6nn,m. Die glolehen Sender werden s u c h a m Observa~or ium ffir Ionosphii, r en fo r sehung K f i h t t m g s b o r n u n d am Geophys ika l i - s e h e n Instit , u t der Tseheehosl . Akad. d. ~,Viss. in P r a g regis t r ie r t , so dai3 ffir oine Z u s a m - m e n a r b e i t bei der Boarbei tun~. oinzelner P rob l eme eine gu te Vorausset, zung gegeben ist. Die F r e q u e n z e n 245 kIffz u n d 272 k H z werden rail: S iehorhe i t a n der E - S e h l e h t ( tags- fiber tei lweise an ebxer oberen D-Sehieh t ) reflekt~iert. Die Messungen e r l auben g le ichzei t ig eino guto E r f a s s u n g dot Dt~mpfungsersehe inungen in der D-Seh ieh t .

2. P R I N Z I P D E R M E S S U N G E N -

Die R e g i s t r i e r u n g des abend l i ehen und n f c h t l i c h e n Raurnwel lene in fa l l s ( - - 5 ~ Sonnen- hShe bis Sendeschlu13) im Langwei lenbere ieh erfolgv n a e h der yon Sprenger [1] an~ege- ber ten Methode u n t e r A u s b l e n d u n g der Bodemvel le des gew/thl ten Senders m i t Hi l fe e ines Pe i l r ahmens . Die Auspe ihm~ erfolgt in den Mit t .agss tunden. d.a zu dieser Zei t die Fe lds t t i rke der R a u m w e l l e infolge s t a r k e r D/~mphmg in ([er D-Seh ieh t u n t e r der E m p f i n d - l iehkeics3chwelle des E m p f a n g e r s liegt.

*) Ansehr i f t : Geophys ika l i sehes Obse rva to r ium, Collm fiber Osctlatz, D D R .

Stud ia geoph , e t ge od . 5 {196D 277