The Interplanetary Magnetic Field: Statistical Properties and Discrete Modes

We report here detailed statistical studies of power spectra of one hour average interplanetary magnetic field (IMF) data that were acquired by the magnetometer instrument on the Ulysses spacecraft in the ecliptic plane of the heliosphere during Ulysses' cruise phase from Earth to Jupiter (October 1990 through January 1992). We have pursued these studies in order to examine in a critical manner our previously published conclusions [TML; Thomson et al, 1995] that energetic particle fluxes in the interplanetary medium carried signatures of discrete modes. We attributed these signatures to the existence of solar acoustic and gravitational modes (p- and g-modes, respectively) in the heliosphere. Here we first examine the statistical distributions of g-modes that are predicted by a theoretical model of the solar interior.