Radio and radar astronomy - lunar and planetary ionospheres, atmospheres, and surfaces, and radar studies of sun and interplanetary mediu

Eshleman, V. R.

English

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I 
V. 2. EshlCcmac 
Project Director 
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i 
a 2 a nsi; upward eleetmn flux of about 3.7 x 16 
Xn the afternoon Inoum, when the tmnperature in the uppes ntrnosphere starts 
ePec/am / sec  has been detected. 
t~ cwl dum, a net domwapd electron flux of about 2.8 x 10 8 elec/cm 2 /SOC 
has Men observed. T-perature changes have been observed by other workers, 
notably, 3, V. Evans' incoherent backscatter measurewent5 at the Millstone 
B i l l  radar station showed a large increase in temperature between ennriso 
A s i n g l e  model of the clslranar rcedjlm beyond the  earth'^ ionosphere, 
ba5sed on the combined data would have the JPslPowing charaeterlstice: 
b. This change I n  dene3l;y slppea~s to occur with high gradients in 
the general region of the shook front; am3 
imd that two months of data san Ice collected before prepzrstfon f o r  the 
launch of P-io?leer is Bsgun, 
2 

Planetary Atnospheres and Ionoapb@reo 
Stanford’s pm*tieipatlon in tile Marfnes IV telemetry occultatSon experi- 
However, thia grant does not COVBT the data analysis $0 that the austafning 
g m t  (EsG-m’, w i l l  still be rcuppsrtlng t h i s  portion of the work unt i l  
addftional funding is provided. 
FrelimZnary analysis sf the Bkrfnar TY occultation data yj-elds an 
srtnornphede nmber d m s i t g  at ‘the 5urface of Mars which is about 1 percent 
of the earth’s iatenospherlic nmber decraity at  sea l e v e l .  (The scale heagist 
near the szrrface is a b u t  8 - 10 hi,] Both the atmosplierlc and formspheric 
densities and acalo kmfghta wsm 16x38 than previously anticipated. 
sufficiently short t i m e  resolutions. Pn addition, the wavslengtli and G a p i n g  
Solar Radar Program 
u1 
5% technlques whhh have been developed during tho 1963 and 1964 solar 
0 
radar rum we now baing readied ~ Q P  w e  i n  the forthcoming serfes of runs 
scheduled for August and September 19%. 
, A few minor changefit are being made in circuitry a~ri data formats t o  
f a c i l i t a t e  processing, but the naflnetayn, as before, w i l l  be the 3CX)-kw 
trmmitter, the 48-oIement I Q ~ - ~ ~ F ~ Q C I I C  array, the  IW 1620 computer for 
analog-to-digitsl conversion, and the IBM 700 computes for digital. cor- 
reinrthn. Each run -11 consfst of a 16-minute s fgnel ,  frequency shift-keyed 
i n  a pseuCorluldon manner between two fsequencies near 25 Mc which a m  50 kc 
apart. The keying Entex*vsl dll again be four seconds. 
Data froin the 1964 solap radar mns, all of which exhibited a S ~ O W  
fluctuating cxmpnent, have been exmlned ~ 5 t h  tm eye towrrd sclving thfs 
ovWient frm exerrpinrst%on 02 the data alone and did not- appear until. after 
5 
4 
Polarfeation of! Decametric RsdbnZ:on from Jupiter 0 
Recent stualim of YupPter’s bocconetric radiation have shown that: 
(1) it ie generated by a non-thermal meehanlm; (2) it occurs sporadically; 
(3) it I s  dfrectfonal and rotating mlth Jupiter; (4) f t  has narrow spectral 
bnndw¶dth; and (5’) i t  &a polarfesd. 
Io, exerts a strong fndlucnce en the planet’s decametric radio a ~ i s s i o n .  
The general gredmiriance of t P e  right-hand sense of polorriaratlan near i3J Bllc 
has been observed, but left-hand sense of polarization is seen more Pre- 
quently at  longer wavelengths, Seven1  observers have noted a change from 
right-hand 00 left-hand sense end back a g ~ f a  in about a Leal-minnte period. 
XonoapheTic Faraday retation prodwoa a spread i n  the orientat2on of polan- 
&eation ellipaers due t o  d%spsrs%on kAthfn a f infee receiver bandwidth. 
in order to mfnimfze th1s effect, it f a  Ohus nscsssarg to make pobricatjon 
It appears that Jupiter’s satellite, 
0 2ngBSUIQFil811tS W%th t28FP’Otv b m d  PWfd.Tt9PS e 
Analyafe of seIatfviat2.c @%facts in t‘no %olnr wind on t h e  :mBr?izi.n%Son 
of a propagating rad10 wave predfcts that abservablc changes mzy occui- in 
the elliptie%Ey m-d the sonso of poXar9zatfon sf radie+ion r ~ t 1 - t ~ ~  than 
simply ~ ~ t a t i n g  the polarlxat%on ellfpse. 
fngly  valuable in permitting n study oP propertscs cf solar wind w i x g  
Yupfter as 8 probe. 
l%is phenomenon can prove excaeZ- 
A totel power radiometer operating at; 26.3 Me has been constructed 
whfeh measures the orthogon@’l i n t e n s i t i e s  of the incoming radi,a.tior,. It 
consists of a pair of cmss-pol mixed,  log-pexiodic antciinza cmnectcd to 
t w o  similar reeel1 e m .  The antemas sre equatcrialf j ;  mounted aacl 
7 
mechanically dflven to  trac Jupiter about nine hours each day. The local 
oscfllalors are common to both receivers so 616 t o  preserve the pI1ass rela- 
tionship between tho orthogonal components of t he  radiation. 
outputs are recorded on a two-channel s t r i p  chart recorder, w h i l e  455 kc 
IF outputs further converted to 5% cps are recoPded on an FX magnetic tape 
~ O T  detailed analysis o f  polarization characteristics. Stpip chart record- 
ings are used to identify po3sible &pfter events. 
events is made by playing back the magnetic t ~ p 8  and actually Ytstenfng 
to familZar "swishing" sounds of noise stoma. m a  tw-charns~ %nfotra.~%on 
of FM magnetic tppe i n  sampled at  a 3.3 kc rate and d ig f t i zod  tzsisg SR IRU 
1620 computer as an analog-to-digltnl converter. 
as an input to mi IBM TOm* conputer, where the Stokes parmeters, vhich 
completely define the sta te  of polarization of radiation, are coraputed. 
The receiver gains are perLodkcaily calibrated against the output of LL 
&ode noise g@nsra&or. 
db. 
The diode 
F i n d  se'lectiom o€ 
T e  dig-lt lzed data cervr?B 
Crosstalk between two receivers i s  less than -& 
me main source of interaction between turn channels f a  t f i r ~ g h  antenna 
emesI;alk which fs about -&) ~3b 3% 26.3 IC. A~iafysfs cl" %YE S~.?pi i ;~r  C V ~ T L S  
and one S Q ~ S  event recorded fn the first m e k  of ;h.z,anst 1965 is cierrcntlg 
in progress. 
mieoret:Lcal and py=c"Lcd work on this project  cat3 sta:*%ed t ~ n d ~ r  Qhc 
HMA Grant and is now funded i n  par t  by the Xntisnal Scf.ieliee Found2%5on 
under grant no. NSF GP-3931. 
3 
PUBLICATXONS 
0 
Howard, H, T. and W. C. Ericbon, Ground-Based Blstat lc  Radar Astronamy, 
J. Geophy8. R-., E, 1270-1272, 1965. 
go Ma Range, IBBE Tmw.  on Antennae and Pmpagatfon, AP-12, 363-368, 
Howard, H. T., An Antenna Array for Rsidpr Astronomy Studitm i n  the 20 to 
19% 
Bshleman, V. E., Radar Astronomy of Solar System Pla6aa8, ch. 14 f r o m  
Solar System Radio Astronmy, ed, J. Aamn8, Plenum Prea8, Inc., 
Hen York, 267-293, 1965. 
Kllore, A. Y., I). L. Cain, G. 8 .  Levy, V. R. Eshlernrrn, F. S I .  Drake, and 
0. Fjeldbo, The Mnrlner 4 Occultation Experiment, Astronautics and 
Aeronautics, 3, no. 7, 72-8a, July 1965. 
Fjeldbo, c). and V. R. Eshlemm, The B i 8 t a t l C  Radsn-Uccultation Method for 
the Study of Planetary Atmwpherea, J .  Ckwphys. R e B . ,  E, 937-3226, 
1965. 
Fjeldbo, 0. and V. R .  Eshleznan, The Eistat ic  Radar-Occultation Method for 
the Study of  Planetary Atmospheres, Sc i .  R p t .  no. 3 ,  NsG-377, 
Stanford Electronics ?.,&oratories, Stanford, Callfornia, 
Spilru, P. I&, I)etgnnfnation of Relative Delay of Pseudorandm Coded Signals 
i n  the Presence of Multtpath Using Mgital  Correlation, S C ~ .  ~ p t .  no. 6 ,  
, Stanford Electronics Laboratories, Stanford, 
FJeldbo, G . ,  V. R. Eshleman, 0. K. C%r,rsiott, end F. It. Smith, 133, %e T-o- 
Frequency, BAS-Lntlc, Fkidar=&ciiltstion Xetkod for kh= Study af Place- 
tscry Ionospheres, 
~ ~ ~ - 6 5 - 0 2 0 - 0 6 5 ,  El octmnlcs hbortrtorf os, 
, iJsCi-377, and S c i .  Rpt. no. 3 ,  
Stanford, California, A p r i l  1965. 
Eow~sd, B. T., V. R. Eshleman, 0. 8. Barry, and R. B .  Fenwick, R a d m  
M?sunuenents of the Total Cislunar Electron Content, pci. Rpl .  no. 8, 
StPinPord Electronics hboratorieoe, Stznford, 



Research at the Stanford Center for Radar Astronomy Semiannual report no. 5, 1 Jan. - 30 Jun. 1965

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