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Reflected solar wind ions and downward accelerated ionospheric ions during the January 1997 magnetic cloud event
Author(s) -
Dempsey D. L.,
Burch J. L.,
Huddleston M. M.,
Pollock C. J.,
Waite J. H.,
Wüest M.,
Moore T. E.,
Shelley E. G.
Publication year - 1998
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 - 10.1029/98gl00334
Subject(s) - solar wind , ionosphere , physics , geophysics , ion , field line , magnetic cloud , magnetic reconnection , interplanetary magnetic field , convection , pitch angle , atmospheric sciences , computational physics , astrophysics , plasma , meteorology , quantum mechanics
On January 11, 1997, at 03:40:00 UT, while Polar was traveling up the dusk flank toward apogee, two ion instruments, TIDE and TIMAS, detected upflowing H + with an energy/pitch‐angle dispersion resembling an ionospheric reflection of freshly injected solar wind ions. In the same region of space, TIDE and TIMAS observed cold beams of O + and H + traveling down the field line with equal bulk velocities. We interpret these ion signatures as concurrent observations of mirrored solar wind ions and downward accelerated ionospheric ions. By 03:42:00, an energy/pitch‐angle dispersion of downward moving ions at very low energies was clearly evident in the TIDE data. This additional signature is interpreted as an indication of reconnection on the same field line in the southern hemisphere. We explain this unique combination of plasma distributions in terms of high‐latitude reconnection and magnetic field line convection during northward‐IMF conditions associated with the January 1997 magnetic cloud event.