Low Energy (>~40 keV) Ions and Electrons of possible Jovian origin in the outer Heliosphere (Ulysses) and near Earth (ACE) betwe

Authors
Abstract:
Low energy ion flux / spectral modulation and magnetic field directional variations with the Jupiter rotation period (~10 hours) were observed by Ulysses during its Distant Jupiter Encounter, as long as Ulysses moved from north to south heliolatitudes, between days 290/2003 - 90/2004. In general this ~10 hour ion modulation was found to be more evident around times of passage of CIRs and was observed by Ulysses after the detection of Jovian bKOM and nKOM ~10 hours emissions. In addition, characteristic ~40 min periodic variations were often seen superimposed on the ~10 hour flux increases (for example days 348-352/03). However, a more surprising ion phenomenon could be seen observed in the heliosphere between days ~320-332/03. Previous studies have already shown that Ulysses observed the passage of a coronal mass ejection (CME) between d. 320-324 / 03 (Koning et al. [2005]) and that Jovian >~3 MeV electrons werw ejected within the CME (McKibben et al, 2005). On days 329-331 / 03 (25-27, November 2003), a series of ~10h separated short (~1-3 hours) duration low energy (~0.05 - ~2.00 MeV) ion bursts were observed by the spacecraft ACE, which were accompanied by ~10 hour spectral variation of low energy (~40 - ~100 keV) electrons and ~10/5 hour quasi-periodic IMF directional variations. At those times, ACE was at a distance of ~240 RE from Earth and located near IMF lines connecting Sun with Jupiter. The analysis of energetic ion pitch angle distributions suggest that a large scale particle layer was “near” ACE for a long time (~2.5 days) and approached / removed quasi-periodically (~10 hours) from the ACE spacecraft. During the main phase of ACE ion bursts, field aligned flows from the antisunward direction were observed, but a comparison of simultaneous observations at ACE, Goetail, IMP-8 and geostationary spacecrafts (LANL-01A, LANL-02A, LANL-97A, 1994-084, 1991-080, 1990-095) rather suggest that the Earth’s magnetosphere / bow shock was not the source of the ~10 / 5 quasi-periodic ion flows. We believe that the Jovian magnetosphere triggered by the impact of the CIRS (CME) was most probably the source of the ~10 quasi-periodicities in low energy ion observations in the outer (inner) heliosphere during the time period examined in this study.
Session:
Presentation Type:
Talk
Presenter:
G.C. Anagnostopoulos
Contact Name:
G.C. Anagnostopoulos
Email:
ganagno@ee.duth.gr
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