Premium
‘Torus’ distribution of interstellar helium pickup ions: Direct observation
Author(s) -
Oka M.,
Terasawa T.,
Noda H.,
Saito Y.,
Mukai T.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl015111
Subject(s) - physics , torus , helium , pickup , ion , scattering , magnetic field , interplanetary spaceflight , distribution (mathematics) , atomic physics , pitch angle , astrophysics , computational physics , plasma , astronomy , nuclear physics , optics , solar wind , geometry , mathematics , quantum mechanics , artificial intelligence , computer science , image (mathematics) , mathematical analysis
A‘torus’‐like velocity distribution of the helium pickup ions has been detected in interplanetary space by GEOTAIL. A statistical survey shows that the observation probability of the ‘torus’ distribution amounts to nearly 20% and that the distribution pattern depends on the local magnetic field directions and turbulence levels. These results support the recent finding of a low pitch angle scattering rate and a large mean free path.