sura-wind experiments: intensity fluctuations due to faraday effect
DESCRIPTION
Yu. Tokarev, Yu. Belov, G. Boiko, G. Komrakov. SURA-WIND experiments: intensity fluctuations due to Faraday effect. Radiophysical Research Institute, N.Novgorod, Russia. Authors are grateful to J.-L. Bougeret ( LESIA, Meudon, France ) - PowerPoint PPT PresentationTRANSCRIPT
SURA-WIND experiments: intensity fluctuations due to Faraday effect
Yu. Tokarev, Yu. Belov, G. Boiko, G. Komrakov
Radiophysical Research Institute, N.Novgorod, Russia
Authors are grateful to J.-L. Bougeret (LESIA, Meudon, France) and M.Kaiser (NASA/GSFC, Greenbelt, USA) for fruitful collaboration
SURA radar facility
Vasil’sursk, Russia (56.07 N, 46 E)
Operating frequency 4.3 – 9.5 MHz
Antenna array sizes 300 m x 300 m
Zenith angle range –45o - +45o
Circular polarization modes (O or X)
Three transmitter submodules
Effective power radiation 17–160 MW
WIND spacecraft
RAD2 WAVES receiver
Operating frequency range 1.075 –13.835 MHz
Two orthogonal dipole antennas X(11m) and Y(15m)
Spinning vehicle (3 sec per turn)
Sensitivity 7 nV/ Hz0.5 Freq. width 20 kHz Sampling rate 63 ms
Sunward WIND orbits
Ecliptic plane localization
Revolving axis is pointed to South ecliptic pole
Apogee 80 – 250 Re
Perigee 10 – 15 Re
Development of high frequency pecularity during the s/c moving away the Earth magnetosphere
effsws RVf
skmswV /400
Eeff RR )40...15(m33 Hzfs )3...1(
WIND trajectory Fluctuation spectra of received SURA signals
Example of spectrum decomposition to ionospheric and IPS components
Example of time record with pronounced Faraday effect
Total intensity Itot and Iz / Itot ratio
December 27, 1999
Example of session with regular Iz / Itot variations
November 23, 1999
Example of session with quasi-regular Iz / Itot variations
Aug 18-19, 1999
Iz and Itot fluctuation spectra of Faraday fringes Aug 18-19, 1999
Iz dynamic spectrum of Faraday fluctuations Aug 18-19, 1999
Degree of linear polarization and total intensity Aug 18-19,1999
Degree of linear polarization and total intensity November 23, 1999
Basic equations
cos)()()(103
)(2
1
317
221
cmLcmNGHRM
RMLnnc
e
100,5.0,35
103 kmLGHcmeN
Ionosphere:
6
1006.1,5
103,3
1.0 kmLGHcmeN
Magnetotail:
=33 m
Faraday rotation angle
Rotation measure
tt sin2
105.4
Hzht 51071/15 HzA |sin|103 2
Characteristic frequencyof Faraday fluctuations:
14
10
Degree of linear polarization of SURA radiation:
),()cos1/(sin 22 AconstZZPlin Z– zenith angle, A – azimuth of line of sight
cos105.4 2
CONCLUSIONS
• A method to study the polarization state of radio signals of ground-based transmitters using RAD2 WAVES observations for SEP-mode is proposed.
• It was found that degree of linear polarization of SURA
emission out the earth ionosphere is close to expected value only for angular range near center of the radar beam.
• Obtained results could be used for calibration of space radio
instrumentation particularly of the STEREO radio receivers at first stage of the mission.
References
C.G.M.van't Klooster, Yu.Belov, Yu.Tokarev, J.L.Bougeret, B.Manning, M.Kaiser. Experimental 9 MHz Transmission from Vasil'sursk in Russia to the WIND Spacecraft of NASA. Preparing for the FUTURE. 1995. V.5. N.4. P.1-3.
Yu.V.Tokarev, M.Kaiser , Yu.I.Belov, G.N Boiko, N.V.Muravieva. Small-scale turbulence of solar wind around the near-Earth bow shock. Astronomicheskii Vestnik. 2000. V.34. N.2. Pp.1-4 (in Russian).
N. A. Barkhatov, N. S. Belliustin, J.-L. Bougeret, S. Yu. Sakharov and Yu.V. Tokarev. Influence of solar wind magnetic field on small-scale near-earth turbulence. Izvestya VUZov, Radiophysica. 2001. V.44. N 12. Pp.993-1002 (in Russian).
N.Muravieva and Yu.V.Tokarev. Decametric sounding of near Earth plasma:correlation and fractal analysis of scintillation data. Astrophysics and Space Science. 2001. V.277. P.331-334.
Yu.V.Tokarev. Turbulence of geo-disturbed region of solar wind (SURA-WIND experiments). Proc. of FSU Conference “Actual problems of solar physics and star activity”. N.Novgorod, June 2-7, 207, 2003. V I. Pp. 191-196 (in Russian).