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Stochastic heating and acceleration of minor ions by Alfvén waves
Author(s) -
Wang Bin,
Wang C. B.,
Yoon P. H.,
Wu C. S.
Publication year - 2011
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 - 10.1029/2011gl047729
Subject(s) - acceleration , ion , physics , geophysics , geology , minor (academic) , atmospheric sciences , computational physics , classical mechanics , quantum mechanics , political science , law
The present paper addresses the stochastic heating of minor ions by obliquely‐propagating low‐frequency Alfvén waves in the solar wind. An important characteristics of the stochastic heating is unearthed by means of test particle simulation. That is, when the wave amplitude exceeds some threshold condition for stochasticity, the time‐asymptotic kinetic temperature associated with the minor ions becomes independent of the wave amplitude, and it always approaches the value dictated by the Alfvén speed, to wit, T kin. ∼ m i v A 2 /2. During the course of the heating process the minor ions gain a net average parallel speed, v ∥ ∼ v A in the laboratory frame. These results are consistent with observations which find that minor heavy ions often move faster than the local protons with a speed roughly equal to the local Alfvén speed.