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Cluster Workshop VI, 1-3 October, 2003 ESTEC

Delve into narrow current sheets and lower hybrid turbulence at the magnetopause, analyzing Cluster data and scales. Understand plasma energy transport, momentum equations, and generalized Ohm's law. Explore reconnection phenomena and wave generation in the current sheet.

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Cluster Workshop VI, 1-3 October, 2003 ESTEC

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  1. A.Vaivads, B. N. Rogers, M. André, S. Buchert, N. Cornilleau-Wehrlin, A. Eriksson, A. Fazakerley, Y. Khotyaintsev, A. Lahiff, B. Lavraud, T. Phan Cluster Workshop VI, 1-3 October, 2003ESTEC • Narrow current sheets and • lower hybrid turublence • at the magnetopause

  2. Cluster and magnetopause scales • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  3. Small scales and waves,what we want to know? • Structure? sheet vs tube local vs global dispersion relation • Transport plasma energy (particles, Poynting flux) • Momentum equationGeneralized Ohm’s law free energy • Energy conversion j·E • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  4. Density dip ~1c/wpi • Narrow current sheet (yellow) 5-10le,re • Strongest E fields within the current sheet • Differences among s/c in E and B. • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  5. Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  6. Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  7. Generalized Ohms law and Cluster • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  8. E~j x B, all 4 s/c • Potential drop across the current sheet of a few 100 V • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  9. 5-10le,re current sheet,jperp and jII • B and n gradients coincides • E~j x B • pe not important • e- beam carrying jII can generate waves • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  10. Generalized Ohms law and Cluster • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  11. Reconnection in 2-fluid 2D MHD, Ey [Rogers] • Reconnection with a guide field • Width of separatrix is a few c/wpe • E is strong along the separatrix • E ~j x B along separatrix • dype small • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  12. Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

  13. Waves strongest in the narrow current sheet (gradient in n and B) • Broad band • Spectral peaks f~fLH • Spectral peaks f~100 Hz, ’whistlers’ • Poynting flux associated to both ’whistlers’ and ’LHD’ • Waves generated by gradients or electron beams? n E • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary E B S  S

  14. Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary • 15-35 Hz band-pass filter (LH) • kre~1 • low coherence • wave transports e- across the current sheet. • D10-9 m2/s, Diffusion?

  15. Summary • Strongest E (10s mV/m) within narrow current sheets ~10 c/wpeon magnetospheric side of MP • E~jxB, pe is not important • Separatrix of reconnection Other explanations? • Strong lower hybrid drift waves and whistlers • Electron transport due to LHD waves can be important only within the current sheet • D 109 m2/s, diffusion? • Intro • Cluster • MP crossing • E~jxB • Separatrix • Waves • Summary

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