Tracking IMF Fluctuations Nearby Sun Using Wavelet Analysis: Parker Solar Probe First Encounter Data

The Parker Solar Probe (PSP) satellite was launched by NASA in 2018 to study the Sun’s environment from a closer distance than any spacecraft has ever reached before, revealing new insights about our star. Based on past few encounters data, numerous crucial findings have been already discovered; the data collected by the probe during each encounter is serving a unique opportunity to enhance our current understanding of solar behaviour. In the present work, we studied fluctuations on interplanetary magnetic field (IMF) ( B ) and its components, Bx , By , and Bz , from 0.50 AU (when PSP moved towards the Sun) to 0.17 AU (closest distance covered by PSP from the Sun) to 0.50 AU (when PSP moved back from the Sun) using continuous and discrete wavelet analysis. Continuous wavelet analysis presented localization of abrupt changes in both time and frequency domains. It revealed high power short-term fluctuations between 0.30 AU (when PSP moved towards the Sun) to 0.30 AU (when PSP moved back from the Sun) with key periodicity in the range of 4 to 64 hours. However, Bx showed high-power long-term fluctuation between 0.34 AU (when PSP moved towards the Sun) to 0.40 AU (when PSP moved back from the Sun) on a timescale of 128–256 hours, which was not reported before. Further, we decomposed the data into high and low-frequency signals using discrete wavelet transform (DWT), and the result revealed significant fluctuations on the IMF when the PSP was moving around the closest distance (0.17 AU). CWT and DWT emerged as sophisticated statistical methods capable of detecting variations in solar wind data in order to gain a better understanding of a specific solar event period and uncover scientific understanding about solar behavior near the Sun.