Wave-particle interactions in the magnetosheath/magnetosph ere boundary layers Alexandra Teste, G. K. Parks, M. Wilber, N. Lin SSL, University of California, Berkeley 17th Cluster Workshop Uppsala Universitet, Sweden 2 nd Waves session Thursday, May 14, 2009 Acknowledgement to D. Fontaine for providing access to the electron data and to Y. Voitenko for discussing the wave data
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Wave-particle interactions in the magnetosheath/magnetosphere boundary layers
Wave-particle interactions in the magnetosheath/magnetosphere boundary layers. Alexandra Teste, G. K. Parks, M. Wilber, N. Lin SSL, University of California, Berkeley. 17th Cluster Workshop Uppsala Universitet, Sweden 2 nd Waves session Thursday, May 14, 2009. - PowerPoint PPT Presentation
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Wave-particle interactions in the magnetosheath/magnetosphere
boundary layers
Alexandra Teste, G. K. Parks, M. Wilber, N. Lin
SSL, University of California, Berkeley
17th Cluster Workshop
Uppsala Universitet, Sweden
2nd Waves session
Thursday, May 14, 2009
Acknowledgement to D. Fontaine for providing access to the electron data and to Y. Voitenko for discussing the wave data
• BL = Msheath population accelerated ~ 300 eV & heated ~ 900 eV
Magnetospheric event within the magnetosheath: Magnetospheric event within the magnetosheath: May 2, 2003May 2, 2003
• Cluster 3 at ~ (6.6, -5.8, 11.1)gse Re• southward turning of IMF
A. Teste 17th Cluster Workshop May 14, 2009
01:30 01:32 01:34 01:36 01:38 01:40 01:42
Ene
rgy
(eV
)
102
103
104
101
ions
e- (anti-//)
Bx
ByBz
|B|
ExEy
Ez
Efie
ld (
mV
/m)
-5
5
10
0
Bfie
ld (
nT)
0
40
-40
Ene
rgy
(eV
)
102
103
104
ergs
/(cm
².s.
sr.e
V)
Xgse (Re)20 10 0 -10 -20
Zgs
e (R
e) 10
20
30
0
-10
-20
-30
Ene
rgy
(eV
)
e- (//)
e- (anti-//)
e- ()
ergs
/(m
².s.
sr.e
V)
Msheath
Msphere
outer inner
diffusion across inner & outer BL
direction
Internal structure and characteristics of the boundary layer Internal structure and characteristics of the boundary layer (BL)(BL)
diffusion across inner BL only
// & anti// directions
Msheath
Msphere
outer inner
Our study: characterization of these 2 regions from particle and wave points of view
Robert et al., 2005; Fear et al., 2005 & Owen et al., 2008: FA ct-streaming BL pop. & inner/outer BL
BL
A. Teste 17th Cluster Workshop May 14, 2009
-10 -5 0 5 10Velocity (1.e4 km/s)
f (s3/m6)
10-18
10-14
10-22iso. diff. msph. e-
-10 -5 0 5 10Velocity (1.e4 km/s)
diff. msph. e-
10-14
10-18
10-22
f (s3/m6)
//, anti//MsheathMsphere
Ene
rgy
(eV
)
e- (//)
e- (anti-//)
e- ()
01:30 01:32 01:34 01:36 01:38 01:40 01:42
ergs
/(m
².s.
sr.e
V)
01:30 01:32 01:34 01:36 01:38 01:40 01:42
High E: 1500-9000 eV
• Typical ES waves (Anderson et al., 1982):
Waves in the magnetospheric domainWaves in the magnetospheric domain
Outer BL: anisotropic diffusion of Mspheric pop. EMEC waves
A. Teste 17th Cluster Workshop May 14, 2009
Waves in the boundary layerWaves in the boundary layer
100
10
1000 Mag.
V²/
(m².
Hz)
101
102
103
Fre
quen
cy (
Hz)
104Elec.
Fre
q. (
Hz)
-0.2
T/T
// -1
0.0
0.4
0.8
B (
nT²/
Hz)
10-11
10-9
10-7
10-5
• ~ 710 Hz• ce ~ 1.4 kHz
EMEC waves (outer BL)
• (k,B) ~10°- 30°
with N = 0 and v 3.2 keV = diffused Mspheric e-
ceNvk ////
01:30 01:32 01:34 01:36 01:38 01:40 01:42
1.2 < Ee- < 15 keV
at ~ 700 Hz
Ene
rgy
(eV
)e- (anti-//)
e- ()
ergs
/(m
².s.
sr.e
V)
Msheath
Msphere
outer inner
diffusion across inner & outer BL
direction
SUMMARY SKETCHSUMMARY SKETCH
diffusion across inner BL only
// & anti// directions
Msheath
Msphere
outer inner
BL
A. Teste 17th Cluster Workshop May 14, 2009
-10 -5 0 5 10Velocity (1.e4 km/s)
f (s3/m6)
iso. diff. msph. e-
-10 -5 0 5 10Velocity (1.e4 km/s)
diff. msph. e-
10-14
10-18
10-22
f (s3/m6) //, anti//MsheathMsphere
-10 -5 0 5 10Velocity (1.e4 km/s)
10-14
10-18
10-22
f (s3/m6)
-10 -5 0 5 10Velocity (1.e4 km/s)
10-14
10-18
10-22
f (s3/m6)
EM e- cycl. waves
Conclusion:Conclusion:
The boundary layer is composed of:
• outer BL: - Msheath plasma: FA, counter-streaming and only accelerated - anisotropic diffusion of Mspheric plasma distribution unstable to EMEC waves
• inner BL: - Msheath plasma: FA, counter-streaming, accelerated & heated and denser than outer BL
- isotropic diffusion of Mspheric plasma - weak wave activity if any
Questions:Questions:
• what is the heating process of low E e- in inner BL & why isn’t at work in the outer BL too?
• why is diffusion anisotropic in the outer BL?
• why do the spikes gather together when EM e- cyclotron waves are observed?