Turbulence in the solar wind: spectra from Voyager 2 data at 5 AU
| Autor: | Luca Gallana, M. Opher, John D. Richardson, Federico Fraternale, Daniela Tordella, Michele Iovieno |
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| Rok vydání: | 2015 |
| Předmět: |
Solar System
010504 meteorology & atmospheric sciences Astronomical unit FOS: Physical sciences Probability density function 01 natural sciences Power law Spectral line law.invention law Intermittency 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Mathematical Physics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences Physics Turbulence Condensed Matter Physics Physics - Plasma Physics Atomic and Molecular Physics and Optics Computational physics Plasma Physics (physics.plasm-ph) Solar wind Astrophysics - Solar and Stellar Astrophysics Physics::Space Physics Astrophysics::Earth and Planetary Astrophysics |
| DOI: | 10.48550/arxiv.1502.07114 |
| Popis: | Fluctuations in the flow velocity and magnetic fields are ubiquitous in the Solar System. These fluctuations are turbulent, in the sense that they are disordered and span a broad range of scales in both space and time. The study of solar wind turbulence is motivated by a number of factors all keys to the understanding of the Solar Wind origin and thermodynamics. The solar wind spectral properties are far from uniformity and evolve with the increasing distance from the sun. Most of the available spectra of solar wind turbulence were computed at 1 astronomical unit, while accurate spectra on wide frequency ranges at larger distances are still few. In this paper we consider solar wind spectra derived from the data recorded by the Voyager 2 mission during 1979 at about 5 AU from the sun. Voyager 2 data are an incomplete time series with a voids/signal ratio that typically increases as the spacecraft moves away from the sun (45% missing data in 1979), making the analysis challenging. In order to estimate the uncertainty of the spectral slopes, different methods are tested on synthetic turbulence signals with the same gap distribution as V2 data. Spectra of all variables show a power law scaling with exponents between -2.1 and -1.1, depending on frequency subranges. Probability density functions (PDFs) and correlations indicate that the flow has a significant intermittency. Comment: 14 pages, 7 figures. Discussion improved since the previous version |
| Databáze: | OpenAIRE |
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