Characterization of turbulence in the Mars plasma environment with MAVEN observations

Suranga Ruhunusiri; J. S Halekas; J. R Espley; C Mazelle; D Brain; Y Harada; G. A DiBraccio; R Livi; D. E Larson; D. L Mitchell; B. M Jakosky; G. G Howes

doi:10.1002/2016JA023456

Back

Characterization of turbulence in the Mars plasma environment with MAVEN observations

Journal article

Peer reviewed

Characterization of turbulence in the Mars plasma environment with MAVEN observations

Suranga Ruhunusiri, J. S Halekas, J. R Espley, C Mazelle, D Brain, Y Harada, G. A DiBraccio, R Livi, D. E Larson, D. L Mitchell, …

Journal of geophysical research. Space physics, Vol.122(1), pp.656-674

01/2017

DOI: 10.1002/2016JA023456

View Online

Abstract

We characterize turbulence in the Mars plasma environment in a global scale for the first time by computing spectral indices for magnetic field fluctuations (slopes in the magnetic field power spectra) and determining how they vary with frequency and in different regions. In the magnetosheath, unlike in the solar wind, we find an absence of the inertial range which has a spectral index value equal to the Kolmogorov scaling value of −5/3. Instead, as observed in the magnetosheaths of other planets, we find that the spectral indices transition from low negative values close to −0.5 at low frequencies (< proton gyrofrequency) to values much lower than −5/3 at high frequencies (> proton gyrofrequency). This indicates that the pristine solar wind is modified at the Martian bow shock and that the fluctuations are dominated by locally generated fluctuations in the magnetosheath. The absence of spectral indices with the Kolmogorov scaling value indicates that the fluctuations in the magnetosheath do not have sufficient time to interact with one another leading to a fully developed energy cascade. Spectral index values near the Kolmogorov scaling value are observed for the low‐frequency range near the magnetic pileup boundary, and this indicates the presence of fully developed energy cascade. In the wake, we find that the spectral indices have approximately the same values, typically near −2, for both the low‐ and high‐frequency ranges. We observe seasonal variations of the spectral indices, mainly in the upstream region, which indicate the seasonal variations of the proton cyclotron waves. Key Points First global characterization of turbulence in the Mars plasma environment Fully developed energy cascade is absent in the magnetosheath but present in the magnetic pileup boundary Turbulence characteristics at Mars vary seasonally

Turbulence

magnetosphere

Mars

MAVEN

plasma waves

Details

Title: Subtitle: Characterization of turbulence in the Mars plasma environment with MAVEN observations
Creators: Suranga Ruhunusiri - University of Iowa
J. S Halekas - University of Iowa
J. R Espley - Goddard Space Flight Center
C Mazelle - Centre National pour la Recherche Scientifique et Technique (CNRST)
D Brain - University of Colorado Boulder
Y Harada - University of California, Berkeley
G. A DiBraccio - Goddard Space Flight Center
R Livi - University of California, Berkeley
D. E Larson - University of California, Berkeley
D. L Mitchell - University of California, Berkeley
B. M Jakosky - University of Colorado Boulder
G. G Howes - University of Iowa
Resource Type: Journal article
Publication Details: Journal of geophysical research. Space physics, Vol.122(1), pp.656-674
DOI: 10.1002/2016JA023456
ISSN: 2169-9380
eISSN: 2169-9402
Number of pages: 19
Grant note: NASA NSF CAREER NASA Postdoctoral Program
Language: English
Date published: 01/2017
Academic Unit: Physics and Astronomy
Record Identifier: 9984199671102771

Metrics

14 Record Views

44 Times Cited - Web of Science