OBSERVATION OF THE JANUARY 1997 CORONAL MASS EJECTION NEAR THE SUN USING RADIO SOUNDING TECHNIQUE WITH GALILEO SPACECRAFT

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OBSERVATION OF THE JANUARY 1997 CORONAL MASS
EJECTION NEAR THE SUN USING RADIO SOUNDING
TECHNIQUE WITH GALILEO SPACECRAFT A.I. Efimov,
L.N. Samoznaev, V.K. Rudash, I.V. Chashei, M.K.
Bird, D. Plettemeier Inst. Radio Eng. Electr.,
Russian Acad. Sci., 125009 Moscow, Russia Lebedev
Phys. Inst., Russian Acad. Sciences, 117924
Moscow, Russia Radioastronomisches Institut,
Univ. Bonn, 53121 Bonn, Germany Technische
Univ.Dresden,Electrotech.Inst., 01062 Dresden,
Germany
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• Background
• Coronal mass ejections of the 1997
  (January, February, May)
• extensively were studied using in situ
  methods and remote-sensing
• technique, based on the analysis of the
  type II radio emissions,
• generated by CME Fox et al, 1998.
• Other remote-sensing technique based on
  radio sounding of the
• solar wind by the signals of
  spacecraft provides a valuable
• information about CME properties in the
  intermediate heliocentric
• distance range between the solar corona and
  Earth.
• During the GALILEO January 1997 ingress
  S-band signal data
• were acquired when the radio ray path
  proximate point was on the
• east limb at distances 3428 solar radii from
  the Sun.

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GALILEO-97 Frequency Residual at Three Ground
Stations
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(a) GALILEO-97 DOY 8-11, S-band Average
Frequency Residuals (b) WIND-97
(DOY 8-11), Electron Density
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GALILEO-97 Intensity of Frequency Fluctuations
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GALILEO-97 Spectral Index of Frequency
Fluctuation
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GALILEO-97 Cross-Correlation Functions of
Frequency Fluctuations
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• Conclusions
• 1. The GALILEO Solar Conjunction in January 1997
  showed the high sensitivity of the sounding
  signals to the disturbed plasma formations.
• 2. The passage of coronal mass ejections through
  radio ray path causes the next radio effects
• - strong (2-3 fold) increase of the
  frequency fluctuations
• - a steeping of temporal spectra during
  passage of the leading front of
• CME
• - blue shift of the average frequency at
  passage of the leading front and
• red shift at passage of the trailing part
  of CME
• - cross-correlation functions of the
  frequency fluctuations with the two
• maxima.

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