Onsets and Flapping Studied using a Dynamic Harris Sheet Model M. Connors 1 , R. Lerner 1 , G. Jaugey 2 , B. Lavraud 3 , M. Volwerk 4 , R. L. McPherron 5 1 Athabasca U., 2 U. Joseph Fourier, 3 LANL, 4 Österreichische Ak. Wissensch., 5 UCLA STAMMS-2 Orleans, France September 2007 Image: Mikko Syrjäsuo
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Onsets and Flapping Studied using a Dynamic Harris Sheet Model
Onsets and Flapping Studied using a Dynamic Harris Sheet Model. M. Connors 1 , R. Lerner 1 , G. Jaugey 2 , B. Lavraud 3 , M. Volwerk 4 , R. L. McPherron 5 1 Athabasca U., 2 U. Joseph Fourier, 3 LANL, 4 Österreichische Ak. Wissensch. , 5 UCLA. - PowerPoint PPT Presentation
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Onsets and Flapping Studied using a Dynamic Harris Sheet Model
M. Connors1, R. Lerner1, G. Jaugey2,
B. Lavraud3, M. Volwerk4, R. L. McPherron5
1Athabasca U., 2U. Joseph Fourier, 3LANL, 4Österreichische Ak. Wissensch., 5UCLA
STAMMS-2 Orleans, France September 2007 Image: Mikko Syrjäsuo
Athabasca University Geophysical Observatory (AUGO)
54.72 N, 246.7 ECGM (2005) 62.0, 306.5L=4.55
Founded 2002(UCLA mag 1998)
A comprehensive observatory in western Canada ideally located for THEMIS conjunctions (see poster)
Harris modelHarris model
Magnetic field :
where By=Bz=0
and Bo = Blobes
Current density :
derived from
Plasma sheet - Harris modelPlasma sheet - Harris model
0 zx JJ
Plasma sheet : hot plasma
n = 3 cm-3
Eth ~ 4200 eV
B ~ 10 nT
β ~ 6
z>0 => Bx>0 , z<0 => Bx<0
)tanh(L
ZoZBB ox
)²(sec)(0
0
L
ZoZh
L
BJy
)(0 BJ curl
Bo
Method for Harris sheet fitting
• The Levenberg-Marquardt nonlinear fitting method was used for BX(Z0,L,B0) during the slow traversal of Cluster through the plasma sheet
• The Levenberg-Marquardt nonlinear fitting method was used for BX(Z0,L) with B0 held constant during flapping
• Thompson et al. (2005 JGR) used a similar fitting technique
Cluster Plasma sheet crossing September 22th, 2001
Plasma sheet crossing at Plasma sheet crossing at ~ 5 UT~ 5 UT