Evidence for Nonlinear Development of Magnetohydrodynamic Scale Intermittency in the Inner Heliosphere
Abstract
The formation of coherent structures in turbulence is a signature of a developing cascade and therefore might be observable by analyzing inner heliospheric solar wind turbulence. To test this idea, data from the Helios 2 mission, for six streams of solar wind at different heliocentric distances and of different velocities, were subjected to statistical analysis using the partial variance of increments (PVI) approach. We see a clear increase of the PVI distribution function versus solar wind age for higher PVI cutoff, indicating development of non-Gaussian coherent structures. The plausibility of this interpretation is confirmed by a similar behavior observed in two-dimensional magnetohydrodynamics simulation data at corresponding dimensionless nonlinear times.
- Publication:
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The Astrophysical Journal
- Pub Date:
- April 2012
- DOI:
- 10.1088/0004-637X/749/2/105
- Bibcode:
- 2012ApJ...749..105G
- Keywords:
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- magnetohydrodynamics: MHD;
- solar wind;
- turbulence