The formation of the plasmapause: Dynamical
simulations
V. Pierrard
Belgian Institute for Space Aeronomy
J. Lemaire (Plasmapause mechanism)
J. Cabrera (IMAGE observations)
F. Darrouzet (CLUSTER observations)
Mechanism of plasma instability Kp increases E increases in the morning sector
The convection velocity increasesErosion of the plasmasphere in the post-midnight sector
Formation of a plume
Lemaire and Gringauz,The Earth’s plasmasphere, Cambridge University Press, 1998.
Input: KpE5D equatorial electric field (McIlwain, 1986)
Empirical model determined from observations of ATS5 and ATS6
Dynamical simulationsPierrard and Lemaire, Geophys. Res. Lett., 31, 5, 2004.
9 June 2001
8h00
9 June 2001
16h00
23h00
10 June 2001 7h00
18 June 2001 13h00 -14h00- 15h00- 16h00
18 June 2001 18h0020h00
June 25, 2000, 21h00 BETWEEN SUBSTORMS
June 26, 2000, 16h00 SUBSTORM
May 24, 2000, 9h00 STORM
May 2, 2001, 18h00 VERY QUIET
Kp – L relation * Numerical simulations for constant Kp
-- Linear relation from Carpenter and Anderson [1992]
+ EUV/IMAGE Kp decrease
+ EUV/IMAGE
Kp increase
MLT=20:00, Kpmax=3, small separation distance (~150km)
Plume observed in the inbound pass at the same time
08:30 UT20:10 MLT CLUSTER
07 May 2002
06
12
24
18
08:32 UT20:10 MLT
7.7-8.1 RE
WHISPER: Waves of High frequency and
Sounder for Probing of Electron density by Relaxation
07 May 2002: Simulation, EUV and CLUSTER
Equatorial projection ofEUV image at 08:31 UT:Plume close to the sameMLT sector (23-24)
Simulations based on the instability mechanism
Use the Kp dependent electric field model E5D
Shoulders and plumes are associated to particular Kp evolutions.
The position of the plasmapause depends on Kp and its evolution with time.
Comparisons with IMAGE give similar structures in the same LT sector.
Conclusions
