An imprint of the quiet plasma sheet structure at the orbit of viking : Magnetosphere without substorms

• We present a study of the plasma sheet structure as seen on VIKING during prolonged periods of magnetic quiescence. The ion and electron spectrograms, the electric field data and field-aligned current signatures in the magnetic field data are examined. A special attention is paid to cases when the Low Latitude Boundary Layer-like plasma is seen deep in the nightside at latitudes which apparently map to close geocentric distances as it implies an exotic plasma circulation in the tail. An attempt has been made to infer from VIKING data how the quiet plasma sheet is formed, whether it originates mainly from the mantle source via the interaction with the distant tail current sheet or whether the lateral transport of the Low Latitude Boundary Layer (LLBL) from the tail flanks (with essentially adiabatic particle motion) takes place followed by the sunward convection in the central part of the near-Earth tail. The VIKING plasma and electric field data suggest that the last mechanism is decisive for plasma sheet structuring during prolonged periods of northward IMF.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geofysik (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geophysics (hsv//eng)

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