Etudes statistiques de la puissance des ondes à la magnétopause et à son voisinage (Traversées Cluster). Corrélations avec la pression du vent solaire.

Présentation au sujet: "Etudes statistiques de la puissance des ondes à la magnétopause et à son voisinage (Traversées Cluster). Corrélations avec la pression du vent solaire."— Transcription de la présentation:

1 Etudes statistiques de la puissance des ondes à la magnétopause et à son voisinage (Traversées Cluster). Corrélations avec la pression du vent solaire. David Attié, Nicole Cornilleau-wehrlin, Gérard Belmont, Laurence Rezeau C.E.T.P (Vélizy) Traversées 2001-2003 (Attié et al 2006,JGR, en révision) Traversées 2004-2005 (Groupe thématique)

2 Period July 2001 to June 2003. Magnetopause crossings by CLUSTER either on the day side at high latitudes, or at low latitude on the flanks. Crossings distribution in YZ plane(GSE frame).

3 CLUSTER 1, 2001/02/14, MP crossing fgm Bx (nT) By Bz (gse) Freq(Hz) Cluster 1 whisper (natural) Staff-sc (  B 2 z,sr2) Statistics on MP and adjacent MSH wave power. Wave power and amplification at the MP. External source for MP wave activity? Role of B rotation?

4  (deg) Role of B rotation in wave power and amplification Strong correlation between wave power and B rotation at the MP. Wave power Amplification into the boundary Weak amplification (low rotation) nT 2  (deg) Strong amplification (high rotation) P * max  (deg)

5  B power (0.35-10 Hz, STAFF), 1s resolution. B L,LMN frame (FGM) B rotation (LM plane) Peak power Pmax(nT 2 ) Average power P msh (nT 2 ) nT 2 nT  (deg) B rotation and wave power calculation. Time(HH:MN:SS)

6 Solar wind dynamic pressure(nPa) P * msh The wave power in MSH is correlated with the solar wind dynamic pressure (thanks to ACE data). Such a behaviour might take part of driven reconnection scenarios. Solar wind influence (years 2001-2003) Normalized power (0.35-10Hz)

7 P * msh Normalized power (0.35-10Hz) Solar wind dynamic pressure(nPa) Solar wind influence (years 2004-2005) 7-11 nov 2004 1 janv 2005

8 Subsolar point (distance in Re, Sibeck model) P * msh Solar wind influence (years 2004-2005) Normalized power (0.35-10Hz) 7-11 nov 2004 1 janv 2005

9 Evidence of an external source y=21x 1.12, r=0.96 The wave power is normalized to the local magnetic field. An amplification and a strong correlation appears between the turbulence level of MP and MSH. Turbulence in MSH can be see as an external source to the high wave activity at the MP. P * msh P * max