Nature of the MHD and kinetic scale turbulence in the magnetosheath of Saturn: Cassini observations
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Low-frequency turbulence in Saturn's magnetosheath is investigated using in situ measurements of the Cassini spacecraft. Focus is put on the magnetic energy spectra computed in the frequency range of ~[10−4, 1]Hz. A set of 42 time intervals in the magnetosheath were analyzed, and three main results that contrast with known features of solar wind turbulence are reported. (1) The magnetic energy spectra showed a ~f−1 scaling at MHD scales followed by an $\sim {f}^{-2.6}$ scaling at sub-ion scales without forming the so-called inertial range. (2) The magnetic compressibility and the cross-correlation between the parallel component of the magnetic field and density fluctuations $C(\delta n,\delta {B}_{| | })$ indicate the dominance of the compressible magnetosonic slow-like modes at MHD scales rather than the Alfvén mode. (3) Higher-order statistics revealed a monofractal (multifractal) behavior of the turbulent flow downstream of a quasi-perpendicular (quasi-parallel) shock at sub-ion scales. Implications of these results on theoretical modeling of space plasma turbulence are discussed.
Date Issued
2015-11-04
Date Acceptance
2015-10-11
Citation
Astrophysical Journal Letters, 2015, 813 (2)
ISSN
2041-8213
Publisher
American Astronomical Society
Journal / Book Title
Astrophysical Journal Letters
Volume
813
Issue
2
Copyright Statement
© 2015 The American Astronomical Society. All rights reserved.
Sponsor
Science and Technology Facilities Council (STFC)
The Royal Society
Science and Technology Facilities Council
Grant Number
ST/K001051/1
RP140004
ST/N002776/1
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
magnetic fields
planets and satellites: individual (Saturn)
plasmas
turbulence
waves
SOLAR-WIND TURBULENCE
MAGNETIC-FIELD FLUCTUATIONS
WEAKLY COLLISIONAL PLASMAS
CLUSTER OBSERVATIONS
DISSIPATION RANGE
ASTROPHYSICAL GYROKINETICS
TERRESTRIAL MAGNETOSHEATH
ALFVEN WAVES
BOW SHOCK
IDENTIFICATION
0201 Astronomical And Space Sciences
Publication Status
Published
Article Number
L29