American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 159031 bytes)    Cited by

GEOPHYSICAL RESEARCH LETTERS, VOL. 30, NO. 21, 2079, doi:10.1029/2003GL017921, 2003

Dependence of the decay phase of solar energetic electron events on the large-scale IMF structure: ACE observations

Emmanuel T. Sarris

Space Research Laboratory, Democritus University of Thrace, Xanthi, Greece


Olga E. Malandraki

Space Research Laboratory, Democritus University of Thrace, Xanthi, Greece


Abstract

Using recent measurements of energetic electrons (≥38 keV) by the ACE/EPAM experiment, we examine the dependence of the characteristic decay time of two impulsive solar electron events on the large-scale structure of the Interplanetary Magnetic Field (IMF) within which the electrons are emitted. The technique of mapping the solar wind and extrapolating the frozen-in magnetic field is used to obtain the large-scale IMF structure within and beyond the location of the ACE spacecraft. We find that the electron event that occurred within a converging IMF structure exhibits a remarkably longer decay phase compared to the electron event observed inside a diverging IMF configuration. The observations provide strong evidence for the location of magnetic “barriers” in space beyond 1 AU and their role in determining the decay phase of solar energetic electron events and the establishment and maintenance of particle reservoirs in the heliosphere.

Received 9 June 2003; accepted 25 August 2003; published 1 November 2003.

Index Terms: 2102 Interplanetary Physics: Corotating streams; 2114 Interplanetary Physics: Energetic particles, heliospheric (7514); 2134 Interplanetary Physics: Interplanetary magnetic fields; 2164 Interplanetary Physics: Solar wind plasma.

Read Full Article (file size: 159031 bytes)    Cited by

Citation: Sarris, E. T., and O. E. Malandraki (2003), Dependence of the decay phase of solar energetic electron events on the large-scale IMF structure: ACE observations, Geophys. Res. Lett., 30(21), 2079, doi:10.1029/2003GL017921.