egs xxvii general assembly nice, france, april 2001 auroral field-aligned acceleration cluster...
TRANSCRIPT
EGS XXVII General Assembly
Nice, France, April 2001
AAuroral field-aligned uroral field-aligned accelerationacceleration
Cluster resultsCluster results
Vaivads A. and Cluster Auroral Team Vaivads A. and Cluster Auroral Team
André M., Backrud M., Buchert S., Olsson A., Kistler L. M., Mouikis C., Quinn J. M., Bosqued J.-M., Cornilleau-Wehrlin N., Fazakerly A., Marklund G., Newell P., Janhunen P., Rauch J.-L., Kadokura A., Taguchi M.
slide 2.
Outline
Cluster orbitCluster orbit 28 April 2001 DMSP/Cluster conjunction28 April 2001 DMSP/Cluster conjunction Aurora vs MagnetopauseAurora vs Magnetopause ConclusionsConclusions
slide 3.
Cluster on auroral field lines
Auroral acceleration
GeneratorOrbit in March
after Parks(1991)
Energy transportTemporal evolutionEquipotential line closure
Orbit in September
Generator E.j <0?particle flux?
slide 4.
How does equipotential lines close?
Mozer 2001 Janhunen et al., 2001
Cluster Cluster
FAST
Polar
DMSP
slide 5.
Cluster/DMSP conjunction
S hemisphereMLT ~20Geomagnetically quiet3kV aurora~200W/m ~15km
ovt s/c1 2001-04-28 1900-1940
Syowa
Plasma sheet boundary layerLow latitude boundary layer
slide 6.
Ground mapping
GMlong85 92
GMlat
-70
-80
s/c 4 +3.5 min DMSP F14 +3.5min
s/c 1
s/c1 2001-04-28 1915:30 UT
s/c 2,3 +2.5 min
Auroral arc
slide 8.
DMSP F14 observations
•Arc width ~10-15 km in ionosphere
•Inetgrated energy flux ~200 W/m. (max 20mW/m2)
•Acceleration potential ~3kV.
slide 13.
Other energy sources
H+ [eV]
Efl[mW/m2]
40 W/m
Ions as energy source ?
SII[mWs/m2]
Waves ? (1-10Hz)
1.5 W/m
slide 18.
Aurora vs Magnetopause
•Can we infer E|| from measurements of Eperp
•OUTstanding small scales vs BIG scales
slide 19.
Conclusions
Cluster/DMSP conjunctionCluster/DMSP conjunctionenergy flux balanceenergy flux balance
DMSP ~220W/m / Cluster ~70-200W/mDMSP ~220W/m / Cluster ~70-200W/magreement with U-potentialagreement with U-potential
DMSP ~3kV / Cluster ~2-5kVDMSP ~3kV / Cluster ~2-5kVtop of the auroral cavitytop of the auroral cavityions or waves cannot power aurora (in this case)ions or waves cannot power aurora (in this case)
Aurora vs MagnetopauseAurora vs Magnetopauseinfer Einfer E|||| from E from Eperpperp