TY  - STD
AU  - Senior, C.
AU  - Cerisier, J-C
AU  - Thorolfsson, A.
AU  - Lester, M.
PY  - 2002//
TI  - Propagation in the ionosphere of convection changes following a sharp interplanetary magnetic field By transition
T2  - J. Geophys. Res.
BT  - Journal of geophysical research-atmospheres
VL  - 107
PB  - American Geophysical Union
KW  - 2463 Ionosphere: Plasma convection
KW  - 2740 Magnetospheric Physics: Magnetospheric configuration and dynamics
N2  - The nature of the response of the ionospheric convection to changes in the interplanetary magnetic field (IMF), either quasi-simultaneous over the polar cap and auroral region or propagating with the flow velocity from the noon sector, remains to be understood. We examine the changes in the ionospheric plasma convection associated with a negative to positive transition in the dawn-dusk component (By) of the IMF. A special mode of operation of the SuperDARN HF radars has been used, which provided both a large field of view and high-resolution convection data on three beams. Close to noon, the most characteristic response concerns the position in magnetic local time (MLT) of the merging gap, the ionospheric footprint of the magnetopause reconnection line, which moves longitudinally with a velocity of 1 km/s. In addition, modifications of the convection, which are indirectly related to this motion, are observed. We attribute them to the “quasi-instantaneous” effect related to the incompressibility of the plasma. Far from noon, in the morning sector, the convection reacts with an intermediate delay, which is neither instantaneous nor compatible with the above propagation velocity. A timing of the transition, based on the IMP 8 and Geotail satellites, located on the dawn flank of the magnetosphere and at the nose of the magnetopause, respectively, indicates that the ionospheric perturbation originates at the impact site of the By transition close to 1300 MLT, with a maximum delay of 3 min after it hits the nose of the magnetopause.
SN  - 0148-0227
UR  - http://dx.doi.org/10.1029/2001JA005078
N1  - exported from refbase (http://publi.ipev.fr/polar_references/show.php?record=5623), last updated on Tue, 28 Apr 2009 09:29:17 +0200
ID  - Senior_etal2002
ER  -