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Anomalous Cosmic Rays
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Discovery of the precise location of trapped ACRs
in the magnetosphere.
Measurement of the elemental composition of trapped
ACRs, including C,N,O, and Ne.
Discovery that the trapped anomalous cosmic rays are
the dominant component of high energy (> 10 MeV) ions heavier than He in the
magnetosphere.
Determination that ACR nitrogen, oxygen and neon
are singly charged.
Determination that the upper limit of ACR O2+ is
less than ~10% of the total ACR oxygen, thus limiting acceleration time scales
in the heliosphere.
Discovery that the interplanetary spectrum of
anomalous oxygen extends to at least 100 MeV/nuc implying that the ACR
acceleration mechanism (termination shock?) accelerates particles to at least
1.6 GeV.
Discovery (in collaboration with Voyager,Ulysses,
and Pioneer spacecraft) that the ACR intensity increases with heliolatitude
during the 1993 approach to solar minimum, in contrast to the opposite
behaviour observed at the previous solar minimum; this confirms predictions of
one class of particle transport theories which include particle drift.
Discovery (in collaboration with Voyager,Ulysses,
and Pioneer spacecraft) that the radial gradients of ACR are much smaller in
the current solar minimum than during the previous solar minimum in 1987.
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Solar Energetic Particles
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Determination of "normal" solar system isotopic
abundances for Ne and Mg in the large solar particle events of Oct/Nov 1993.
Excesses (factor ~4) of neutron rich isotopes of Ne
and Mg in 3He-rich solar particle events
Demonstration that high-energy (> 1 MeV/nuc)
heavy ions in the large solar particle events of late 1992 were partially
ionized charge states, similar to those reported previously for energies
near 1 MeV/nuc, with the exception of Fe, which had a significantly lower
ionization state.
Demonstration that the energy spectra of impulsive
3He-rich events routinely extend to > 10 MeV/nuc
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Middle Atmosphere Physics
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Discovery that electron flux variations at SAMPEX
altitudes are well correlated with solar wind variations, providing a
solar-magnetosphere-middle atmosphere coupling.
Demonstration that the priomary relativistic
electron flux inputs into the middle atmosphere occur in the range
3.5<L<5.5, corresponding to subauroral latitudes.
Discovery that relativistic electron energy inputs
into the middle atmosphere are asymmetric between the northern and southern
hemispheres, with the largest inputs occuring in the southern hemisphere.
Within each hemisphere, there are preferred longitudes for the enrgy inputs.
Indication that relativistic precipitating
electrons provide a significant source of odd nitrogen to the middle
atmosphere and can affect middle atmospheric ozone.
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