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Dynamical age of solar wind turbulence in the outer heliosphere
- Source :
- Journal of Geophysical Research: Space Physics. 103:6495-6502
- Publication Year :
- 1998
- Publisher :
- American Geophysical Union (AGU), 1998.
-
Abstract
- In an evolving turbulent medium, a natural timescale can be defined in terms of the energy decay time. The time evolution may be complicated by other effects such as energy supply due to driving, and spatial inhomogeneity. In the solar wind the turbulence appears not to be simply engaging in free decay, but rather the energy level observed at a particular position in the hellosphere is affected by expansion, "mixing," and driving by stream shear. Here we discuss a new approach for estimating the "age" of solar wind turbulence as a function of heliocentric distance, using the local turbulent decay rate as the natural dock, but taking into account expansion and driving effects. The simplified formalism presented here is appropriate to low cross hellcity (non-Alfvnic) turbulence in the outer hellosphere especially at low hello-latitudes. We employ Voyager data to illustrate our method, which improves upon the familiar estimates in terms of local eddy turnover times.
- Subjects :
- Atmospheric Science
K-epsilon turbulence model
Soil Science
K-omega turbulence model
Aquatic Science
Oceanography
Magnetohydrodynamic turbulence
Physics::Fluid Dynamics
Geochemistry and Petrology
Earth and Planetary Sciences (miscellaneous)
Earth-Surface Processes
Water Science and Technology
Physics
Ecology
Turbulence
Time evolution
Paleontology
Forestry
Mechanics
Dissipation
Solar wind
Geophysics
Classical mechanics
Space and Planetary Science
Physics::Space Physics
Heliosphere
Subjects
Details
- ISSN :
- 01480227
- Volume :
- 103
- Database :
- OpenAIRE
- Journal :
- Journal of Geophysical Research: Space Physics
- Accession number :
- edsair.doi...........8eaa30c5ec9b710737e853d804da26d3
- Full Text :
- https://doi.org/10.1029/97ja03729