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| Titel |
Waves, instabilities and turbulence properties in Depolarisation Fronts |
| VerfasserIn |
Giovanni Lapenta, Martin Goldman, David L. Newman, Vyacheslav Olshevskyi, Jonathan Eastwood, Andrey Divin, Francesco Pucci |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123917
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| Publikation (Nr.) |
 EGU/EGU2016-3258.pdf |
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| Zusammenfassung |
| The new mission MMS is currently focusing on the magnetopause but we need to be ready for the study of the tail. An aspect of great importance there are the Dipolarization fronts (DF), formed by reconnection outflows interacting with the pre-existing environment. These regions are host of important energy and wave phenomena [1-3]. Our recent work has investigated these regions via fully kinetic 3D simulations [4-5].
As reported recently on Nature Physics [3], based on 3D fully kinetic simulations started with a well defined x-line, we observe that in the DF reconnection transitions towards a more chaotic regime. In the fronts an instability develops caused by the local gradients of the density and by the unfavourable acceleration and field line curvature. The consequence is the break up of the fronts in a fashion similar to the classical fluid Rayleigh-Taylor instability and the onset of waves and secondary instabilities, transitioning towards a turbulent state.
We investigate here especially the wave signatures that are observed in fully 3D simulations, looking for signatures of interchange-type lower hybrid waves [8], of whistler waves [7]. The end result present a vast array of waves and it is best analysed relying on concepts mutated by the turbulence theory.
The end result of these waves and particle flows [2,6] are energy exchanges. We evaluate the different terms of the energy exchanges (energy deposition, J.E, and energy fluxes) and evaluate their relative improtance. The results presented are contrasted against existing results [1,9] and will provided useful guidance in analysis of future MMS data.
[1] Hamrin, Maria, et al. "The evolution of flux pileup regions in the plasma sheet: Cluster observations." Journal of Geophysical Research: Space Physics 118.10 (2013): 6279-6290.
[2] Angelopoulos, V., et al. "Electromagnetic energy conversion at reconnection fronts." Science 341.6153 (2013): 1478-1482.
[3] Zhou, Meng, et al. "THEMIS observation of multiple dipolarization fronts and associated wave characteristics in the near‐Earth magnetotail." Geophysical Research Letters 36.20 (2009).
[4] Lapenta, Giovanni, et al. "Secondary reconnection sites in reconnection-generated flux ropes and reconnection fronts." Nature Physics 11.8 (2015): 690-695.
[5] Vapirev, A. E., et al. "Formation of a transient front structure near reconnection point in 3‐D PIC simulations." Journal of Geophysical Research: Space Physics 118.4 (2013): 1435-1449.
[6]Eastwood, J. P., et al. "Ion reflection and acceleration near magnetotail dipolarization fronts associated with magnetic reconnection." Journal of Geophysical Research: Space Physics 120.1 (2015): 511-525.
[7] Goldman, M. V., et al. "Čerenkov emission of quasiparallel whistlers by fast electron phase-space holes during magnetic reconnection." Physical review letters 112.14 (2014): 145002.
[8] Divin, A., et al. "Evolution of the lower hybrid drift instability at reconnection jet front." Journal of Geophysical Research: Space Physics 120.4 (2015): 2675-2690.
[9] Eastwood, J. P., et al. "Energy partition in magnetic reconnection in Earth’s magnetotail." Physical review letters 110.22 (2013): 225001. |
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