Observations of diverging field-aligned ion flow with the ESR

International audience We report on observations of a diverging ion flow along the geomagnetic field that is often seen at the EISCAT Svalbard radar. The flow is upward above the peak of the electron density in the F-region and downward below the peak. We estimate that in such events mass transport...

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Bibliographic Details
Main Authors: Buchert, S. C., Ogawa, Y., Fujii, R., van Eyken, A. P.
Other Authors: Solar-Terrestrial Environment Laboratory Nagoya (STEL), Nagoya University, EISCAT Scientific Association
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2004
Subjects:
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean
Atmosphere
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Svalbard
EISCAT
Online Access:https://hal.science/hal-00317268
https://hal.science/hal-00317268/document
https://hal.science/hal-00317268/file/angeo-22-889-2004.pdf
Description
Summary:International audience We report on observations of a diverging ion flow along the geomagnetic field that is often seen at the EISCAT Svalbard radar. The flow is upward above the peak of the electron density in the F-region and downward below the peak. We estimate that in such events mass transport along the field line is important for the ionization balance, and that the shape of the F-layer and its ion composition should be strongly influenced by it. Diverging flow typically occurs when there are signatures of direct entry of sheath plasma to the ionosphere in the form of intense soft particle precipitation, and we suggest that it is caused by the ionization and ionospheric electron heating associated with this precipitation. On average, 30% of all events with ion upflow also show significant ion downflow below. Key words. Ionosphere (polar ionosphere; ionization mechanism; plasma temperature and density)

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