Statistical analysis of solar wind parameter variation with heliospheric distance: Ulysses observations in the ecliptic plane. Issue 12 (15th June 2020)

• Record Type: Journal Article
• Authors: Echer, E.; Bolzan, M.J.A.; Franco, A.M.S.
• Is Part Of: Advances in space research. Volume 65:Issue 12(2020)
• Page Start: 2846
• Page End: 2856
• Publication Date: 2020-06-15
• Subjects: Solar wind turbulence -- Ulysses spacecraft -- Kurtosis technique -- Wavelet analysis; Space sciences -- Periodicals; Astronautics -- Periodicals; Geophysics -- Periodicals; 500.505
• DOI: 10.1016/j.asr.2020.03.036
• Languages: English
• ISSNs: 0273-1177

Abstract

Abstract: The interplanetary magnetic field magnitude Bo, proton density Np and solar wind speed Vsw data from Ulysses spacecraft during its interplanetary cruise interval from Earth to Jupiter, from 18 November 1990 to 31 January 1992, are analyzed in this study. Statistical and wavelet techniques are employed to characterize some properties from the solar wind parameters near the ecliptic plane and their dependence with radial distance. The results from kurtosis analysis showed that the three solar wind parameters ( Bo, Np and Vsw ) presented a decrease of this statistical quantity with the increase of scales, indicating that these variables are intermittent in short time scales. Further, the kurtosis parameter presented an increase in all scales around 2–3 AU distance range that corresponds to a solar wind regime transition. It was noted that the interplanetary medium was dominated by solar transients (interplanetary coronal mass ejections) until the middle of 1991. Afterwards a more stable pattern of corotating interaction regions arose. Furthermore, the probability distribution functions presented a spreading shape due to the occurrence of intermittence. In order to study the temporal variability of the solar wind parameters, the wavelet approach was used. The following major periodicities were found for the three solar wind variables studied: ~13, ~26, and ~83–88 days. It was noted that the ~13 day periods presented strong spectral power in the 2 to 4 AU range, where the solar wind was dominated by ICME transients. On the other hand, the 26 day period shows higher spectral power for distances higher than 4 AU, where the interplanetary space is more dominated by CIRs. Thus, it was found in this paper a significant dependence of solar wind parameters on radial heliocentric distance which can be accounted by the dynamical evolution of solar wind structures with distance.