1. 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

2. Magnetospheric event within the magnetosheath: May 2, 2003
Xgse (Re)
Zgse (Re) 10 20 30
-10
-20
-30
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Energy (eV)
102
103
104
101
ions
e- (anti-//) Bx By Bz
|B| Ex Ey Ez
Efield (mV/m) -5 5 10
Bfield (nT) 40
-40
ergs/(cm².s.sr.eV)
Cluster 3 at ~ (6.6, -5.8, 11.1)gse Re
southward turning of IMF
BL = Msheath population accelerated ~ 300 eV & heated ~ 900 eV
A. Teste th Cluster Workshop May 14, 2009

3. Internal structure and characteristics of the boundary layer (BL)
Energy (eV)
ergs/(m².s.sr.eV)
e- (anti-//) BL
 direction
diffusion across inner & outer BL
Msheath
Msphere
outer
inner
// & anti// directions
diffusion across inner BL only
Msheath
Msphere
outer
inner
Velocity (1.e4 km/s)
f (s3/m6)
10-18
10-14
10-22
iso. diff. msph. e-
Our study: characterization of these 2 regions from particle and wave points of view
Velocity (1.e4 km/s)
 diff. msph. e-
10-14
10-18
10-22
f (s3/m6)
Robert et al., 2005; Fear et al., & Owen et al., 2008: FA ct-streaming BL pop. & inner/outer BL
//, anti// 
Msheath
Msphere
A. Teste th Cluster Workshop May 14, 2009

4. Waves in the magnetospheric domain
Energy (eV)
e- (//)
e- (anti-//)
e- ()
ergs/(m².s.sr.eV)
Pitch angle (°)
cnts/sec
101
102
103
104
100 10
1000
Mag.
Frequency (Hz)
V²/(m².Hz)
nT²/Hz
High E: eV
Elec.
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Magnetospheric e- with peaks at intermediate angles  conic-like distributions
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Typical ES waves (Anderson et al., 1982):
- Upper hybrid waves: f~fuH~6.6 kHz: conic-like e-
- ES e- cyclotron waves (f~fce ~1.1 kHz), 1st harmo. f ~2.2 kHz, Bernstein (n=2-5): 2 tenuous loss cones
A. Teste th Cluster Workshop May 14, 2009

5. Waves in the magnetospheric domain
Energy (eV)
e- (//)
e- (anti-//)
e- ()
ergs/(m².s.sr.eV)
101
102
103
104
100 10
1000
Mag.
Frequency (Hz)
V²/(m².Hz)
nT²/Hz
High E: eV
Elec.
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Typical EM waves (Anderson et al., 1982):
- EM e- cyclotron (EMEC) waves: f~400 Hz<fce, right-handed, (k,B)~10°-30°:
 conic-like e-
with broadband ES spikes
A. Teste th Cluster Workshop May 14, 2009

6. Waves in the boundary layer
Energy (eV)
e- ()
ergs/(m².s.sr.eV)
e- (anti-//)
100 10
1000
Mag.
Freq. (Hz)
nT²/Hz
V²/(m².Hz)
101
102
103
Frequency (Hz)
104
Elec.
 ~ 710 Hz
ce ~ 1.4 kHz
EMEC waves (outer BL)
(k,B) ~10°- 30°
with N = and v  3.2 keV = diffused Mspheric e-
-0.2
T/T// -1
0.0
0.4
0.8
B (nT²/Hz)
10-11
10-9
10-7
10-5
at ~ 700 Hz
1.2 < Ee- < 15 keV
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EMEC waves: f < fce, RH polarized, // to B
Outer BL: anisotropic diffusion of Mspheric pop  EMEC waves
A. Teste th Cluster Workshop May 14, 2009

7. SUMMARY SKETCH BL  direction Msphere Msheath // & anti// directions
Energy (eV)
e- (anti-//)
e- ()
ergs/(m².s.sr.eV) BL
 direction
diffusion across inner & outer BL
Msheath
Msphere
outer
inner
Velocity (1.e4 km/s)
10-14
10-18
10-22
f (s3/m6)
Velocity (1.e4 km/s)
 diff. msph. e-
10-14
10-18
10-22
f (s3/m6)
Velocity (1.e4 km/s)
f (s3/m6)
iso. diff. msph. e-
Velocity (1.e4 km/s)
10-14
10-18
10-22
f (s3/m6)
//, anti// 
Msheath
Msphere
EM e- cycl. waves
// & anti// directions
diffusion across inner BL only
Msheath
Msphere
outer
inner
A. Teste th Cluster Workshop May 14, 2009

8. Conclusion: Questions: 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:
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? …