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Multispacecraft Analysis of Electron Holes
Author(s) -
Steinvall K.,
Khotyaintsev Yu. V.,
Graham D. B.,
Vaivads A.,
Lindqvist P.A.,
Russell C. T.,
Burch J. L.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl080757
Subject(s) - physics , spacecraft , electron , ion , computational physics , magnetopause , debye length , plasma , coupling (piping) , nonlinear system , oblate spheroid , atomic physics , magnetosphere , materials science , quantum mechanics , astronomy , metallurgy
Electron holes (EHs) are nonlinear electrostatic structures in plasmas. Most previous in situ studies of EHs have been limited to single‐ and two‐spacecraft methods. We present statistics of EHs observed by Magnetospheric Multiscale on the magnetospheric side of the magnetopause during October 2016 when the spacecraft separation was around 6 km. Each EH is observed by all four spacecraft, allowing EH properties to be determined with unprecedented accuracy. We find that the parallel length scale, l ∥ , scales with the Debye length. The EHs can be separated into three groups of speed and potential based on their coupling to ions. We present a method for calculating the perpendicular length scale, l ⊥ . The method can be applied to a small subset of the observed EHs for which we find shapes ranging from almost spherical to more oblate. For the remaining EHs we use statistical arguments to find l ⊥ / l ∥ ≈5, implying dominance of oblate EHs.