Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Magnetic Reconnection, Turbulence, and Particle Acceleration: Observations in the Earth's Magnetotail
Ist Teil von
Geophysical research letters, 2018-04, Vol.45 (8), p.3338-3347
Ort / Verlag
Washington: John Wiley & Sons, Inc
Erscheinungsjahr
2018
Link zum Volltext
Quelle
Wiley Online Library - AutoHoldings Journals
Beschreibungen/Notizen
We report observations of turbulent dissipation and particle acceleration from large‐amplitude electric fields (E) associated with strong magnetic field (B) fluctuations in the Earth's plasma sheet. The turbulence occurs in a region of depleted density with anti‐earthward flows followed by earthward flows suggesting ongoing magnetic reconnection. In the turbulent region, ions and electrons have a significant increase in energy, occasionally >100 keV, and strong variation. There are numerous occurrences of |E| >100 mV/m including occurrences of large potentials (>1 kV) parallel to B and occurrences with extraordinarily large J · E (J is current density). In this event, we find that the perpendicular contribution of J · E with frequencies near or below the ion cyclotron frequency (fci) provide the majority net positive J · E. Large‐amplitude parallel E events with frequencies above fci to several times the lower hybrid frequency provide significant dissipation and can result in energetic electron acceleration.
Plain Language Summary
The Magnetospheric Multiscale mission is able to examine dissipation associated with magnetic reconnection with unprecedented accuracy and frequency response. The observations show that roughly 80% of the dissipation is from the perpendicular currents and electric fields. However, large‐amplitude parallel electric fields appear to play a strong role in turbulent dissipation into electrons and in electron acceleration.
Key Points
MMS observations reveal characteristics of turbulent dissipation and particle acceleration associated with magnetic reconnection
Perpendicular electric fields and large‐amplitude parallel electric fields structures have dominant roles in turbulent dissipation
Turbulent electric fields in a magnetic structure is shown to play a key role in accelerating electrons to greater than 100 keV energies