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Cold ion demagnetization near the X‐line of magnetic reconnection
Author(s) -
ToledoRedondo Sergio,
André Mats,
Khotyaintsev Yuri V.,
Vaivads Andris,
Walsh Andrew,
Li Wenya,
Graham Daniel B.,
Lavraud Benoit,
Masson Arnaud,
Aunai Nicolas,
Divin Andrey,
Dargent Jeremy,
Fuselier Stephen,
Gershman Daniel J.,
Dorelli John,
Giles Barbara,
Avanov Levon,
Pollock Craig,
Saito Yoshifumi,
Moore Thomas E.,
Coffey Victoria,
Chandler Michael O.,
Lindqvist PerArne,
Torbert Roy,
Russell Christopher T.
Publication year - 2016
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 - 10.1002/2016gl069877
Subject(s) - gyroradius , magnetosheath , magnetic reconnection , physics , magnetopause , ion , magnetosphere , atomic physics , population , plasma , nuclear physics , demography , quantum mechanics , sociology
Abstract Although the effects of magnetic reconnection in magnetospheres can be observed at planetary scales, reconnection is initiated at electron scales in a plasma. Surrounding the electron diffusion region, there is an Ion‐Decoupling Region (IDR) of the size of the ion length scales (inertial length and gyroradius). Reconnection at the Earth's magnetopause often includes cold magnetospheric (few tens of eV), hot magnetospheric (10 keV), and magnetosheath (1 keV) ions, with different gyroradius length scales. We report observations of a subregion inside the IDR of the size of the cold ion population gyroradius (∼15 km) where the cold ions are demagnetized and accelerated parallel to the Hall electric field. Outside the subregion, cold ions follow the E × B motion together with electrons, while hot ions are demagnetized. We observe a sharp cold ion density gradient separating the two regions, which we identify as the cold and hot IDRs.