Frequency fluctuations in the solar corona investigated with radio sounding experiments on the spacecraft ROSETTA and MARS EXPRESS in 2010/2011
| Autor: | Martin Pätzold, A. I. Efimov, Michael K. Bird, I.V. Chashei, L. A. Lukanina, L. N. Samoznaev |
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| Rok vydání: | 2017 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences media_common.quotation_subject Aerospace Engineering Tracking (particle physics) 01 natural sciences Asymmetry Signal 0103 physical sciences 010303 astronomy & astrophysics 0105 earth and related environmental sciences media_common Physics Spacecraft business.industry Astronomy Astronomy and Astrophysics Function (mathematics) Computational physics Solar wind Geophysics Space and Planetary Science Mars express General Earth and Planetary Sciences business Intensity (heat transfer) |
| Zdroj: | Advances in Space Research. 59:1652-1662 |
| ISSN: | 0273-1177 |
| DOI: | 10.1016/j.asr.2017.01.001 |
| Popis: | Coronal radio-sounding experiments were carried out using two-way coherent dual-frequency carrier signals of the ESA spacecraft ROSETTA in 2010 and MARS EXPRESS in 2010/2011. Differential frequency measurements recorded at both NASA and ESA tracking stations (sample rate: 1 Hz) are analyzed in this paper. Spectral analysis of the S-band, X-band, and differential frequency records has shown that the r.m.s. frequency fluctuation of each signal can be described by a radial power-law function of the form σ i = A i ( R / R ⊙ ) − βi , where i = s , x , sx . The ratio of the coefficients A s and A x differs from the expected theoretical value A s / A x = f s / f x . This occurs because the X-band fluctuations underlie two-way propagation conditions while the S-band fluctuations are essentially the product of a one-way propagation experiment. The intensity of the frequency fluctuations decreases sharply at high heliolatitudes. The asymmetry of the frequency fluctuation intensity between ingress and egress is exploited to determine the solar wind speed at small heliocentric distances. |
| Databáze: | OpenAIRE |
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