[Trattner 1996 a]
Ulysses COSPIN/LET:
latitudinal gradients of anomalous cosmic ray O, N and Ne
K. J. Trattner, R. G. Marsden, V. Bothmer,
T. R. Sanderson, K.-P. Wenzel, B. Klecker
and D. Hovestadt.
Ulysses COSPIN/LET: latitudinal gradients of anomalous cosmic ray O, N
and Ne.
Astronomy and Astrophysics, 316, 519-527.
1996
Contents
A key goal of the Ulysses mission is the measurement of the latitudinal
gradient of the Anomalous Cosmic Ray (ACR) component.
Earlier studies using data from the COSPIN/LET experiment on board
Ulysses together with in-ecliptic data from the HILT instrument on
SAMPEX have shown a small (~2% per degree) positive latitudinal gradient
for anomalous oxygen in the energy range 8 to 16 MeV/n.
This result is consistent with the effects of curvature and gradient drifts
in the heliospheric magnetic field for the current polarity configuration:
positively charged particles are expected to flow down to the heliographic
equator from the polar regions.
In this paper we extend our previous work and include two additional ACR
species, nitrogen (4 to 20 MeV/n) and neon (4 to
30 MeV/n).
We also present our latest results on the ACR oxygen latitudinal gradient
over an extended energy range (4 to 20 MeV/n).
The period covered for all three species include the Ulysses south polar
pass, the rapid transit from the south pole to the ecliptic and a
significant portion of the climb to high northern latitudes.
For all species and energy ranges the latitudinal gradients are
between 1% and 2%, consistent with earlier studies, and show a
slight tendency to larger gradients for higher magnetic rigidity.
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