Etudes statistiques de la puissance des ondes la magntopause et son voisinage Traverses Cluster. Cor

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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 RezeauC.E.T.P
(Vélizy)Traversées 2001-2003 (Attié et al
2006,JGR, en révision)Traversées 2004-2005
(Groupe thématique)
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• 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?

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Role of B rotation in wave power and amplification

• Wave power

Strong correlation between wave power and B
rotation at the MP.
Pmax
nT2
? (deg)

• Amplification into the boundary

?(deg)
Weak amplification (low rotation)
Strong amplification (high rotation)
? (deg)
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B rotation and wave power calculation.
Peak power Pmax(nT2)
?B power (0.35-10 Hz, STAFF), 1s
resolution. BL,LMN frame (FGM) B rotation
(LM plane)
Average power Pmsh(nT2)
nT2
nT
? (deg)
Time(HHMNSS)
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Solar wind influence (years 2001-2003)
Normalized power (0.35-10Hz)
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.
Pmsh
Solar wind dynamic pressure(nPa)
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Solar wind influence (years 2004-2005)
Normalized power (0.35-10Hz)
7-11 nov 2004 1 janv 2005
Pmsh
Solar wind dynamic pressure(nPa)
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Solar wind influence (years 2004-2005)
Normalized power (0.35-10Hz)
7-11 nov 2004 1 janv 2005
Pmsh
Subsolar point (distance in Re, Sibeck model)
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Evidence of an external source
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.
Pmax
y21x1.12, r0.96
Pmsh