Simultaneous Analysis of Recurrent Jovian Electron Increases and Galactic Cosmic Ray Decreases

TL;DR

This study analyzes recurrent Jovian electron increases and galactic cosmic ray decreases, revealing phase shifts and the influence of heliolongitude and solar wind conditions on particle propagation in the heliosphere.

Contribution

It provides a detailed analysis of the phase relationship between Jovian electrons and GCRs, highlighting the role of heliolongitude and solar wind in their modulation.

Findings

Phase shift observed between Jovian electrons and GCR decreases during 2007-2008.

Jovian electron variation vanishes when magnetic connection between Earth and Jupiter is absent.

Heliolongitude difference and solar wind speed influence particle propagation and observed variations.

Abstract

The transport environment for particles in the heliosphere, e.g. galactic cosmic rays (GCRs) and MeV electrons (including those originating from Jupiters magnetosphere), is defined by the solar wind flow and the structure of the embedded heliospheric magnetic field. Solar wind structures, such as co-rotating interaction regions (CIR), can result in periodically modulation of both particles species. A detailed analysis of this recurrent Jovian electron events and galactic cosmic ray decreases measured by SOHO EPHIN is presented here, showing clearly a change of phase between both phenomena during the cause of the years 2007 and 2008. This effect can be explained by the change of difference in heliolongitude between the Earth and Jupiter, which is of central importance for the propagation of Jovian electrons. Furthermore, the data can be ordered such that the 27-day Jovian electron variation vanishes in the sector which does not connect the Earth with Jupiter magnetically using observed solar wind speeds.