Over the southern solar pole: low-energy interplanetary charged particles.
The heliosphere instrument for spectrum, composition, and anisotropy (HISCALE) recorded the fluxes of low-energy ions and electrons (> 50 kiloelectron volts) when Ulysses crossed the southern solar polar region and revealed that the large-scale structure of the heliosphere to at least approximately -75 degrees was significantly influenced by the near-equatorial heliospheric current sheet. Electrons in particular were accelerated by the current sheet-produced and poleward-propagating interplanetary reverse shock at helioradii far from the Ulysses location. At heliolatitudes higher than approximately -75 degrees on the Ulysses ascent to the pole and approximately -50 degrees on the descent, small, less regular enhancements of the lowest energy electron fluxes were measured whose relations to the current sheet were less clear. The anomalous component of low-energy (approximately 2 to 5 megaelectron volts per nucleon) oxygen flux at the highest heliolatitudes was found to be approximately 10(-8) [per square centimeter per second per steradian (per kiloelectronvolt per nucleon)]; the anomalous Ne/O ratio was approximately 0.25.
Lanzerotti
L J
LJ
AT&T Bell Laboratories, Murray Hill, NJ 07974, USA.
Armstrong
T P
TP
Gold
R E
RE
Maclennan
C G
CG
Roelof
E C
EC
Simnett
G M
GM
Thomson
D J
DJ
Anderson
K A
KA
Hawkins
S E
SE
Krimigis
S M
SM
D004583:Electrons; D005118:Extraterrestrial Environment; D007477:Ions; D010100:Oxygen; D016082:Solar System; D018531:Spacecraft
D007477:Ions; D010100:Oxygen