Drifting field-aligned density structures in the night-side polar cap

0024213 - ÚFA 2006 RIV US eng J - Journal Article
Santolík, Ondřej - Persoon, A. M. - Gurnett, D. A. - Décréau, P. M. E. - Pickett, J. S. - Maršálek, O. - Maksimovic, M. - Cornilleau-Wehrlin, N.
Drifting field-aligned density structures in the night-side polar cap.
[Driftující hustotní struktury v polární oblasti na noční straně.]
Geophysical Research Letters. Roč. 32, - (2005), L06106-1. ISSN 0094-8276. E-ISSN 1944-8007
R&D Projects: GA ČR(CZ) GA202/03/0832; GA MŠMT ME 650; GA MŠMT 1P05ME811
Grant - others:NASA(US) NAG5-9974; NASA(US) NNG04GB98G; NSF(US) 0307319; ESA PECS(XE) 98025
Institutional research plan: CEZ:AV0Z30420517
Keywords : Magnetospheric Physics * Plasma convection * Plasma waves and instabilities * Polar cap phenomena * Magnetospheric configuration and dynamics
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 2.491, year: 2005

Spatio-temporal properties of density irregularities in the night-side polar cap are inferred from multi-point observations of auroral hiss at a radial distance of 5 Earth radii. In this case study, we use high resolution data of the wave instruments onboard the four Cluster spacecraft to estimate the local plasma density, obtaining values close to 1 cm−3 with density depletions decreasing down to 0.15 cm−3. Combined analysis in different points in space conclusively shows for the first time that these density structures are field-aligned and that they predominantly drift in the anti-sunward direction at speeds of a few km/s. This corresponds to a dawn-to-dusk convection electric field of approximately 1 mV/m. The transverse dimension of the observed density depletions, mapped down to the ionospheric heights, is of the order of a few tens of km. Their lifetime is probably longer than tens of seconds.

Práce popisuje driftující hustotní struktury v polární oblasti na noční straně.
Permanent Link: http://hdl.handle.net/11104/0114794