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Heavy ion acceleration at dipolarization fronts in planetary magnetotails
Author(s) -
Greco A.,
Artemyev A.,
Zimbardo G.
Publication year - 2015
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 - 10.1002/2015gl066167
Subject(s) - ion , physics , atomic physics , acceleration , plasma , gyroradius , particle (ecology) , particle acceleration , front (military) , computational physics , astrophysics , nuclear physics , meteorology , classical mechanics , geology , oceanography , quantum mechanics
Transient reconnection events in planetary magnetotails give rise to fast plasma jets, whose leading edges are called dipolarization fronts. We perform a test particle simulation of the acceleration of several ion species (H + , He + , and O + ) in a 2‐D model of dipolarization fronts. We study the dependence of the acceleration on parameters of the model, finding, e.g., that the average ion energy increases with the front velocity and with the initial injection energy. When the ion species are initially cold, O + ions get the largest amount of average energy. Conversely, when the injection energy of O + ions is increased, their average energy gain does not exceed that of the lighter species, suggesting that ion energization at local dipolarization fronts strongly depends on the initial particle gyroradius. Further, the energy gained by the most energetic fraction of particles scales approximately as the square root of the mass ratio.