Identification of He isotopes by SEPICA is demonstrated in the Figures above, which include energetic particle events that occurred during Sept. 18 through 20 (featured in the 10/27/97 ACE News item from EPAM). Shown are helium mass histograms (not yet fully calibrated) for two energy ranges from these first He-rich solar events recorded by SEPICA. The two histograms suggest a strong variation of the 3He/4He ratio with energy. Data from the SOHO/HSTOF instrument indicate that this trend extends to lower energies, which may open the way for a multi-mission collaborative study.
These solar events also show a substantial enrichment in Fe (as already indicated by EPAM). SEPICA has collected more Fe ions during these three days than were integrated over all 3He-rich events during the entire ISEE-3 mission with SEPICA's predecessor. Although the deflection voltage was only at 3 kV, preliminary analysis shows that low energy Fe ions (50 - 200 keV/nucleon) have charge states of Q = 15 - 25, compatible with results for the entire ISEE-3 sample of 3He-rich events. SEPICA will be able to carry out this charge state analysis for individual flares.
SEPICA was developed by the University of New Hampshire and the Max-Planck-Institut for Extraterrestrial Physics, Germany.
.....contributed by Dr. Eberhard Moebius, UNH.
Last modified 7 November 1997, mrt
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