Open AccessElectron acoustic waves in double‐kappa plasmas: Application to Saturn's magnetosphere
Author(s) -
Baluku T. K.,
Hellberg M. A.,
Mace R. L.
Publication year - 2011
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010ja016112
Subject(s) - magnetosphere , physics , saturn , electron , plasma , atomic physics , radius , magnetosphere of saturn , electron temperature , computational physics , astrophysics , magnetopause , nuclear physics , computer security , planet , computer science
Using a kinetic theoretical approach, the characteristics of electron acoustic waves (EAWs) are investigated in plasmas whose electron velocity distributions are modeled by a combination of two kappa distributions, with distinct densities, temperatures, and κ values. The model is applied to Saturn's magnetosphere, where the electrons are well fitted by such a double‐kappa distribution. The results of this model suggest that EAWs will be weakly damped in regions where the hot and cool electron densities are approximately equal, the hot to cool temperature ratio is about 100, and the kappa indices are roughly constant, with κ c ≃ 2 and κ h ≃ 4, as found in Saturn's outer magnetosphere ( R ∼ 13–18 R S , where R S is the radius of Saturn). In the inner magnetosphere ( R < 9 R S ), the model predicts strong damping of EAWs. In the intermediate region (9–13 R S ), the EAWs couple to the electron plasma waves and are weakly damped.