Ion temperature determination by variations of satellite induced ion trap currents - Electron 2 satellite measurements of ion temperatures in ionospher

Bezrukikh, V. V.

Breus, T. K.

Gringauz, K. I.

English

NASA Technical Reports Server

METHOD OF IXTEIIMIMTION OF ION TEM€WATW 
BY TIE VARIATIONS OF SATELLITE INDUCED ION TRAF' CURFENTS 
ANI) I~STIMATI: OF TIE UPPER LIMIT OF ION TIWERATURE 
AT RLTIRJDES OF 10000 KILOMETERS .WD 1IIGHER 
ACCOFWING 'I'O DATA OF AES "ELEKTRON-2" 
I(. I .  Gringauz 
V .  V .  Hczrukikh 
T. K .  Breus 
(USSR) 
(THRU) 
I 
(CATEGORY) 
2 1  FEHKUARY 1968 
https://ntrs.nasa.gov/search.jsp?R=19680007552 2020-03-12T09:16:42+00:00Z
S'I-izI -PF -10674 - - 
(*> 
Kosmiches kiye I ssledovaniya 
Tom -967. 5 ,  vypusk 2, 245-250, 
SrnbNlY -- 
by K .  I . Gr ingauz 
V.  V.  Hezrukikh 
T.  K .  Breus 
I t  is  shown t h a t  measurements of c o l l e c t o r  cur ren t  v a r i a t i o n s  of an 
ion t rap wi th  zero p o t e n t i a l  a t  ou ter  g r i d ,  i n s t a l l e d  aboard a spinning 
spacec ra f t  f l y ing  within the  ionospherc, may be u t i l i z e d  f o r  the  determi- 
na t ion  of ion  temperature Ti.  
'1%~ estimates of the  upper l i m i t  of  T i  made a f t e r  the  da t a  of the  ion 
t r a p  i n s t a l l e d  aboard M S  "ELEKTKON-2'' have shown tlxt i n  the  a l t i t u d e  range 
4000 - 8000 km the  ternperature of ions d i d  no t  exceed 1O,00Oo K .  
* 
* * 
As f a r  as we know the  f i rs t  rough estimate of ion tcniperature a t  a l t i t u -  
des of the nrdcr  of scvcrnl  thou.;and kilomctcrs was made i n  the  work 111 ;IC- 
cording t o  da t a  of charged pa r t  i c l c  traps iiist;il led  ahoard spacecraf t  "LUNA-2" 
launched i n  1959. 
po ten t ia l s  r e l a t i v e  t o  c r a f t ' s  frame: -10 v , -5  v and +15 v. 
shown t h a t  the  p o s i t i v e  c o l l e c t o r  cur rcn ts  r eg i s t e red  in  t r a p s  a t  a l t i t u d e s  t o  
~ 20,000 km depend e s s e n t i a l l y  on comparatively small d i f  rerences i n  poten t -  
i d s  of t r a p s '  ou te r  g r i d s  having taken p lace ,  whereas i n  the  t r a p  with ou te r  
g r i d  p o t e n t i a l  of +15 L- no pos i t i ve  cu r ren t s  were geiierally r e g i s t e r e d  a t  a l t i  
t d e s  above 3000 km. This is evidence of  comparatively low energ ies  of pos i -  
t i r e  ions in  the  a l t i t u d e  region considered, and it allowed the  authors  of [ I ]  
t o  estimate the  value of T i  i n  t h a t  region as not  exceeding some 10,OOO°K. 
The aitcr gr ids  of  f o u r  t r aps  on I,~JM-2 had the  following 
Experiment has 
Note t h a t  i n  essence simultaneous measurements with the  a i d  of four  t r aps  
\iith d i f f e r e n t  ou te r  g r i d  po ten t i a l s  are equivalent  t o  obta in ing  of four  po in t s  
on t h e  sonde volt-arnperc ~ha r : i c t e r i s t j _c .  
(*) SPOSOB OI'RI:I)ELENIYA IONNOY 'I'E3VI'~~IlA'l'URY PO I ZMENLNTYAM TOKA TONNOY 
LOL'USi&I, \YZVANNMl LRWlCIENlEM SI'LJI'NIKA, I OTSIiNKA Vl~RKIINliGO PIU31>lilA IONNOY 
'~13tP1~1UTl~l'Y NA WSOTIW I 5 10 ,000  01 1'0 I)ANNYK " I ~ L l ~ K l I ~ O N A -  2" 
. 
There e x i s t s  s t i l l  another p o s s i b i l i t y  of estirnriting T i ,  and namely, 
by the  v a r i a t i o n s  of c o l l e c t o r  cur ren t  of a t r a p  w i t h  zero p o t e n t i a l  i n  the  
outer  g r i d  and a f l a t  co l l ec to r  i n s t a l l e d  on a spinning spacec ra f t  ( I'LuNA-?'' 
and "EI,l~K'I'I1ON- 2" were w c h  SpaC-ccrzfts i n  p a r t i c u l a r )  . 
For an a r b i t r a r y  pos i t i on  o f  t h e  t r a p  r e l a t i v e  t o  the  a i s  (o r  axes) of 
r o t a t i o n  of the  spacecraf t  t he  pos i t i on  of t h e  normal t o  t r a p ' s  c o l l e c t o r  
r e l a t i v e  t o  the  " t r ans l a t iona l "  ve loc i ty  vec tor  of the  device ( i . e .  i t s  velo-  
c i t y  along the  t r a j e c t o r y  vI(.,.) must vary pe r iod ica l ly ,  which must, i n  its tu rn ,  
induce corresponding per iodic  va r i a t ions  ("modulation") of the  r e g i s t c r c d  co l -  
l e c t o r  cu r ren t .  Such ; I  modulation o f  c c l l e c t o r  cu r ren t s  was indeed observed 
during the  passage through the  plasma shea th  of the  Earth on both "LUNA-2" 
and on each convolution of AES "ELEKTRON-2" launched i n  1964, on which the re  
was a l s o  i n s t a l l e d  a charged p a r t i c l e  t r a p  with zero p o t e n t i a l  i n  t he  ou te r  
' w i d  0 [ Z J .  I f  we considered t h a t  the maxinium values  of c o l l e c t o r  cu r ren t  of 
such a t r a p  correspond t o  overlappings of the  noma1 t o  c o l l e c t o r  cu r ren t  
with s p a c e c r a f t ' s  ve loc i ty  vec to r ,  and the  minimum values - t o  the  loca t ion  
of t he  t r a p  i n  the  ion shadow, a t  which the  d i r e c t i o n  of the  normal t o  col-  
lector is opposi te  t o  ve loc i ty  vec tor ,  we might determine the  upper threshold 
of I'i by the  r a t i o  of these  values .  
Let us now show how t h i s  i s  done. Assume t h a t :  
1) the  d i s t r i b u t i o n  of charged p a r t i c l e s  by v e l o c i t i e s  i n  the  ionosphere 
is Naxwellian, and the  influence of the  electric f i e l d  induced by s p a c e c r a f t ' s  
p o t e n t i a l  d i f f e rence  from t h a t  of t h e  plasma surrounding it can be neglected;  
2 )  t he  spacec ra f t  sp ins  around an axis perpendicular  t o  the  nromal t o  
t r a p ' s  c o l l e c t o r  cu r ren t ;  t h e  spacec ra f t ' s  " t r ans l a t iona l "  ve loc i ty  vec tor  
l ies i n  ;I plane perpendicular t o  the  ind ica ted  r o t a t i o n  axis; 
5) t he  r e g i s t  r a t  ion of co l l ec to r  cu r ren t  is p r a c t i c a l l y  r e a l i z e d  cont inu-  
oiisly ( t h a t  i s ,  there is  a continuous cu r ren t  r e g i s t r a t i o n ) .  
Note t h a t  i n  r e a l i t y  condi t ions 2) and 3) a r e  usua l ly  not f u l f i l l e d .  This 
is lihy we s h a l l  examine how T i  can be determined i n  the  case of f u l f i l l m e n t  
of t hese  condi t ions ,  and then we shall  es t imate  how the  nonfulf i l lment  of 
these  condi t ions  a f f e c t s  the  r e s u l t  
lie s h a l l  make use of a system of coordinates  with o r i g i n  a t  t he  mass 
c e n t e r  of the  spacec ra f t ,  and the ax is  7, coinciding wi th  t h e  spacec ra f t ' s  
t r a n s l a t i o n a l  ve loc i ty  vec tor .  
Then thc  magnitude of the  maximum t r ap ' s  c o l l e c t o r  cur ren t  w i l l  be d e t e r -  
mined from the  expression 
m c l  t h a t  of cu r ren t  mini inurn by 
. . . . . .  
.x .\ ., . . .  . .  
j .  :.,.; = ;'L . . .  \ \ \ ;:',(*\,.'.:,.. I . I  I 
-x-x. lj 
rd?tre c i.; the  charge of the e l ec t ron ,  S is thc a r - c ~  c.f trap's L - L ~ ~ ~ L ~ L ~ ~ L ~ ~ ,  
c --- L' -vir.;,. is the  ve loc i ty  of ions i n  the  se l ec t ed  system of coord ina tes ,  
? is the  thermal ve loc i t )?  of ions and f(?) is  the  d i s t r i b u t i o n  func t ion .  
-. 
In  accord with the  e a r l i e r  s a id  we  s h a l l  take f o r  f ( v )  a Maxwellian 
d i  s t r  i bu t  ion func t  i on; then 
i n  which the  temperature T i  corresponds t o  t h a t  of ai ionosphere unperturbed 
1)- the  spacec ra f t  ( s ince  we neglectcd the  s a t e l l i t e ' s  p o t e n t i a l ) .  
In tegra t ing  (1) and (2)  and assuming t h a t  t he  concentrat ion of  ions 
I l i  ;it times of measurement of maxirinun and minimum 
we ob ta in  f o r  the  r a t i o  of  cur ren ts  the  following 
-- 
1 
cur ren t s  a r e  i d e n t i c a l ,  
express ion 
here  r = (?/tt921<a /2kTI) ' 'a ,  112 is the  mass of the  proton,  and ( O ( x - 5 )  
funct ion of e r r o r s .  
dcpcrids Cor a known c I Y n  only on T i ;  thus  i f  w e  cons t ruc t  the  dependence of 
lll.l\ / Jl l l l l r l  on x_ o r  on T ,  = wr21ta /2/i.$, w e  may take advantage of  t he  graph 
obtained Tor the  deterniiiiation of Ti. Obviously, as x + 0 ,  i . e .  a t  very 
high tcmpcratures and f o r  .z?> 1 , (I,, nj:ll i 1,. ,1,111 = (1 / xfs)x,jeA. 
f o i  .r *>I) t h i s  r a t i o  becomes extremely g r e a t .  
i s  the  
I t  may be seen from formula (3) t h a t  t he  r a t i o  ~ ~ ~ ~ n ~ l ~ / ~ ~ s ~ ~ l l ~  
,11,1, / I ,% -* 1, 
Part of the  graph of liilll.ly /I illllll  = f? ( z )  dependence f o r  values  of  x i n  
T i  a r e  computed f o r  ~' I \ :L = 8 m/sec. the  range 0.1 < x < 1 . 5  i s  given i n  Fig.  1. 
A s  a l ready  noted,  w e  d ispose of t he  r e s u l t s  of rneasuremcnts of Ik con- 
ducted i n  the  pe r iphe ra l  region of thc  Ea r th ' s  ionosphere ( t o  which we r e f e r  
the  a l t i t u d e s  up t o  10 t o  20 thousand h i )  with t h e  he lp  of ;I charged pa r t i c l e  
t r a p  on IJI,I~K'T'KON-2. 
the  r e s u l t s  of measurements of Ik  f o r  two passages of ELEKTRON-2 near  thc 
Earth.  
ref. [ l ] ) .  
only of po in t s  a t  a l t i t u d e s  I t  may be 
seen from Figs  2 and 5 t h a t  i f  one determines thc  r a t i o  I1~:,l, , ,//~.l, , , , ,  f o r  the  con- 
secu t ive  extreme po in t s  s i m i l a r  t o  those noted,  so t h a t  the rirst one with <. 
low valuc of Ik  correspond t o  lower a l t i t u d e  arid thc  sccond - with g r e a t  valuc 
of  i k  - be rc l a t cd  t o  g r e a t e r  he ight ,  t h i s  value w i l l  c o n s t i t u t e  a magnitude 
of t he  order of 10 .  
For the  sake of an example we brought ou t  in  Figs  2 and .3 
Analogous r c s u l  ts were obtained on spacecraf t  "LUNA- 2" (see Fig. 3 of 
10 ,000  km (marked by t r i a n g l e s ) .  
For t h e  estimate of the ion  temperature w e  s h a l l  takc advantage 
1:ig. 1 Dependence of thc inaxiinurn and miniinum c o l l e c t o r  
cu r ren t  r a t i o s  of  a t r a p  with zero po ten t i a l  a t  ou ter  
g r i d ,  corresponding t o  per iodica l  v a r i a t i o n s  of t r a p ’ s  
pos i t i on  on account of spacecraf t  spinning,  on the  quan- 
t i t y  = I n c v l ,  3. / ? k r ,  [see forniula ( 3 ) ]  - 
. D  I. . . 
7 .  .. . 
c 
I:ig.3. Va1uc.s of’ the collector 
currents of the  t r a p  i n s t a l l t d  on 
l~I , l~Kl’ l~ON-.2 ,  c o r ~ ~ ~ s p o n d i n g  t o  i ts  
passage near the liarth on 31 .Jan. 
1‘364 from 084b t o  0952 hours U.T. 
IIowcwc>r, we may not u t i l i z e  the d a t a  of Figures 2 and 3 f o r  the  deter-  
minxtion of '1'i without es t imat ing  the  dcgrec of fu l f i l lmen t  of condi t ions du- 
r i n g  t h e  expcriment in the  assumption of which the  graph o€ Fig.  1 was p lc , t t ed .  
Let us examine i n  sequence how each of the  admitted assumptions a f f e c t s  
the  determinat ion of T i  by the  method indicated.  
Assumption (1) allowed us t o  consider  t h a t  the  teniperaturc determined liy 
the  proposed method corresponds t o  t h e  temperature of the  ionosphere unperturb- 
ed by the  spacec ra f t ,  inasmxh as its p o t e n t i a l  is near  zero.  
In  our case such an assumption can be subs t an t i a t ed  as follows. 
maximum ionic  cu r ren t s  r eg i s t e red  with the  a i d  of the  charged p a r t i c l e  t r a p s  
aboard IiLEKlRON-2 are compiled i n  [ 2 ] ;  they correspond a l l  t o  same a l t i t u d e s  
(11. 6 10000 km) with s a t e l l i t e  loca t ion  i n  the  cone of- E a r t h ' s  shadow and i n  
thc  region i l luminated by the  Sun. In night t ime condi t ions  the  s a t e l l i t e  PO- 
t c n i t a l  must be negat ive while i n  Sun's i l lumina t ion  it  may change s ign .  This 
circumstance should hc r e f l e c t i n g  upon cu r ren t  magnitude. 
c u r r e n t  values  r eg i s t e red  i n  both cases  poin ts  t o  t h e  smallness of t he  sa te l l i -  
t e  p o t e n t i a l  r e l a t i v e  t o  the  surrounding medium of t h i s  a l t i t u d e  region.  The 
conclusion r e l a t i v e  t o  the  smallness of sa te l l i t e  p o t e n t i a l  i n  the  a l t i t u d e  
region undcr cons idera t ion  by us was a l s o  der ived i n  the  work by Serbu, d e s c r i -  
bing the  r e s u l t s  obtained on the  s t a t i o n  "IMP-1" [ 3 ] .  This is why the  u t i l i z a -  
t i o n  of Ma.wellian d i s t r i b u t i o n  corresponding t o  T = T i  a t  a l t i t u d e s  considered 
should be considered as  j m t i f i e d .  Nete, i nc iden t ly ,  t h a t  the  !%nwellim d i s -  
t r i b u t i o n  is  p rec i se ly  the  one assumed i n  numerous analogous ca l cu la t ions  of 
ion v e l o c i t y  d i s t r i b u t i o n  in  the  ionosphere (beginning wi th  Whipple's work [ 4 ] )  . 
Data on 
The proximity of 
There is no b a s i s  t o  consider t h a t  i n  measurement condi t ions  on ELIXTRON-2 
assumption ( 2 )  was f u l f i l l e d ,  as 110 p rec i se  da t a  were ava i l ab le  t o  us on the  
o r i c n t a t i o n  of  the  noma1 t o  t r a p ' s  c o l l e c t o r  r e l a t i v e  t o  ve loc i ty  vec to r .  This 
might have l e d  t o  the  fact t h a t  i n  process of modulation on account of space- 
c r a f t  spinning the  maximum values  I k  max were found t o  be less than what ought 
t o  have taken p lace  i n  case of coincidence of t h e  normal t o  c o l l e c t o r  with t h e  
s a t e l l i t e ' s  t r ans l a t io i l  ve loc i ty  vec tor ,  t he  minimum values I k  min being co r -  
respondingly over ra ted .  A t  the  same time the  r a t i o  I k  max/Ik mi11 may be below 
the "real"  (obtained f-rom F i g . l ) ,  whilc the  value of  T i  may r e s u l t  t o  he over- 
r;i t cd  . 
FiRall;,, t he  condi t ions of measurement on ELEKTRON-2 d id  not  corrcspond 
t o  :issumption ( 3 )  e i t h e r .  
ionductcJ  ur i inter iuptedly,  but only once i n  two niinutcs. A t  the  same time thc  
i n J i i a t e d  i n t e r v a l  b e t w e n  two comecut ive measurements was by order  of magni- 
tu& c lose  t o  s a t e l l i t e ' s  r o t a t i o n  per iod r e l a t i v e  t o  i t s  cen te r  of masses. 
As ;I soiisequence of this the  r e s u l t s  of measurements p l o t t c d  i n  Figs  2 and 3,  
r e f l e c t ,  because of spacccnf ' t  I s  ro t a t ion ,  not the  au thcn t i c  measurements of I k  
but a c e r t a i n  ' ' q ~ i ~ s i ~ t r o b ~ ~ s C ~ p i C "  pa t t e rn . I f  a t  t he  smie time we choose f o t  
11,: mi11 and Ik  1113s the  p a i r s  of extreme po in t s ,  following one another and o u t l i -  
tied i n  F ig .3  by t r i a n g i e s ,  we f ind  t h a t  : 
The r e g i s t r a t i o n  of Ik a t  a l t i t u d e s  considered was no t  
. . . ./. . 
a) f i r s t l y ,  the  quan t i ty  I k  may be over ra ted ,  f o r  i t  is not  escluJcJ 
t h a t  t h e  mcasurcmcnt was conducte3"at the  moment of time when the  value of 11, 
was not  the  l e a s t ;  
1)) secondly, the  quan t i ty  Ik m a  may LUlderratCd, s ince  measurement may 
have been conducted not a t  t he  moment of time when the  value o f  Ik  was g r e i t e s t ;  
c)  t h i r d l y ,  i t  was assumed t h a t  t h e  concentrat ion of ions a t  time of mea- 
surenlents of l k  max and Ik min 
lilt itucle increase ,  while the  po in t s  a t  which I1\ lnax and I k  Inin were measured 
a t  two minatc i n t e r v a l ,  a r e  found t o  be s i g n i f i c a n t l y  s p a t i a l l y  s c a t t e r e d ;  thus ,  
by s e l e c t i n g  a poin t  with Ik a t  g r e a t e r  he ight  than with Ik min, we obvious- 
l y  lower tiif2 r:ltiO I k  max/ I k  m i l l .  
was equal ;  i n  r e a l i t y ,  concentrat ion drops with 
' f i e re fore ,  scarce  measurements of l k  can only l ead  to  lowering t h e  r a t i o  
I k  In:4x/ I k  m i *  by comparison with the t r u e  value,  i. e .  t o  t he  over ra t ing  of 
the  value of T i  sought f o r .  
I t  follows from the  above-said t h a t  the  nonfu l f i l lment  of cach of the  in -  
This 
d ica ted  condi t ions ( Z ) ,  ( 3 ) ,  may a f f e c t  the  value of T i  being dctcrmincd i n  one 
:ml the  same d i r c c t i o n ,  over ra t ing  it by comparison with the  real value.  
i s  why Ti determined from the  r a t i o s  Ik I k  mint corresponding t o  po in t s  
similar to  those which a r e  out l ined  by t r i a n g l e s  i n  F igs  2 arid 3 ,  must be cons i -  
dered as the  upper threshold ( l imi t )  of poss ib l e  tralues of  T i  i n  the  a l t i t u d e  
rangc cons i &red.  
I n  t h e  p resent  papcr we l i m i t e d  ourselves  t o  the  estimate of the  value of 
Note t h a t  i n  the  a l -  l'i according t o  measurcmcnts p lo t t ed  i n  Figures 2 and 3 .  
t i tuclc region < 10000 km these  da ta  refer t o  the  e a r l i e r  mentioned cases  of 
l ~ l ~ l . K ~ ' R O ~ - 2 1 s  l oca t ion  i n  t he  cone of Ea r th ' s  shadow, when the  s a t e l l i t e ' s  po- 
t c r i t i x l  is knowingly negat ive,  while the  values of thc  c o l l e c t o r  cur ren t  are 
c n t i  r e l y  frce from the  influence of photoemission. 
I t  may be seen from Fig.2 t h a t  the  r a t i o  Ik / Ik min , deterniined by 
the  po in t s  marked by t r i a n g l e s ,  may cha rac t c r i ze  l'i i n  the  4000 - 5200 km a l t i -  
tude rangc, while t he  corresponding a l t i t u d e  in t e rva l  i n  the  case of  Fig.3 is 
5200 - 7800 h. 
the  l a t t e r  ?, 7 kln/sec. 
The s a t e l l i t e  vc loc i ty  i n  the  former was % 8 h / sec  and i n  
111 e i thcr  c;isc l h  lll;lx / l k  ~ l l in  = 10.  'I'lien, according t o  thc  graph of 
l ' i g .  1 ,  f o r  30 .J;iiiuary 19b4 t he  upper 1 imit  of 'I'i is 0000 - 111000'K. 
. J : ~ ~ l u a r ~ *  l!N>-! tlic \';iIuc of T i  est imatcd ailalogously was 'L 7000'K. 
thcse cstiiiilites o f  the  teiriperature of  ions al low us t o  r e f i n e  [lower) the prc-  
L.ious \-:ilucs for thc  indicated a l t i t u d e s  o f  the  uppcr 1 i m i t  of  ternperature 
gi i -en i n  L1 J f o r  t h c  e n t i r e  pcriplicral  region of the Ear th ' s  plasnci sheath.  
For 51 
ThcreTorc, 
'I'hc Ibickrson, Hennctt and Ilale's work was puhlished in  1965 [SI.  In  it  
the  r c~s i i l t s  arc descrihctl of the in t e rp re t a t ion  of da t a  obtained with the  a i d  
o f  tlic i n n  t n p  iiista1it.d 011 ;I rocket i:iunclicd t o  55iiO 'm i n  Ocrobcr 19Ou. 'The 
authors admit a t  the  same t i i n e  t ha t  i n  the  4000 - 5200 km a l t i t u d e  range the  
ioii tcinpcr-:iturc euccedtcl .32000°1i. The wt imatcs prcscnted ;iI>ove a r e  opposed 
t o  such :I pass ih i 1 i t y  . 
" 
i 
121 .  V .  V. 13EZRUKIN1, I(. I .  GRINGAUZ. I S S L .  Kosniicheskogo P r o s t r m s t v a .  
p.177, IZCI-VO "NAUM", 1965. 
[5]. G. I?. SLRIUJ. Space Res. - 5 ,  563, 1905. 
[-I]. 1,. S. \VlIIPPLE. 1)r-o~. IRE, - 4 7 ,  2 0 2 3 ,  1959. 
[ S J  . D .  N. .LWDEKSON, W .  I I .  BENNETT, I , .  C. lWI1. @J.Gcophys. Res. 7 0 ,  hb.5,  
1031, 1955. 
Translated arid edited 
ANDRE I,. I3RTCIWNT 
a t  home 
on 19 m d  2 0  Febri.iar): 


Method of Determination of Ion Temperature by the Variations of Satellite Induced Ion Trap Currents and Estimate of the Upper Limit of Ion Temperature at Altitudes of 10,000 Kilometers and Higher According to Data of AES Electron-2

Method of Determination of Ion Temperature by the Variations of Satellite Induced Ion Trap Currents and Estimate of the Upper Limit of Ion Temperature at Altitudes of 10,000 Kilometers and Higher According to Data of AES Electron-2

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server