Exploring Low Frequency Interplanetary Magnetic Field Spectra at ~0.4 AU using MESSENGER Data

Authors: Rayta Pradata (University of Delaware), Sohom Roy (University of Delaware), Jiaming Wang (University of Delaware), Joshua Goodwill (University of Delaware), Francesco Pecora (University of Delaware), Rohit Chhiber (University of Delaware, NASA GSFC), Yan Yang (University of Delaware), William Matthaeus (University of Delaware).

The 1/f frequency spectra has been observed in various physical systems ranging from solid state physics (Van der Ziel, 1950; Dutta Horn, 1981) to geophysics (Machlup, 1981). Matthaeus & Goldstein (1986) have shown through spacecraft observations that the interplanetary magnetic field at 1 AU follows this spectral dependence. It was derived by Montroll Shlesinger (1982) that a superposition of a random time series with a lognormal distribution of correlation times has an overall 1/f scaling within a specific range of frequencies. This is confirmed by Wang et. al (2024, in prep) using an ensemble of synthetically generated time series with a fixed power law spectrum of index between -3 and -1, and correlation times ranging from 100 to 100,000 seconds. Therefore, this project plans to see how the 1/f scaling law applies to the interplanetary magnetic field at Mercury ( 0.4 AU) using MESSENGER spacecraft observations, and how it compares with the 1 AU observations.