Voyager 2 solar plasma and magnetic field spectral analysis for intermediate data sparsity
| Autor: | Michele Iovieno, John D. Richardson, Sophie M. Fosson, Luca Gallana, Enrico Magli, M. Opher, Federico Fraternale, Daniela Tordella |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
010504 meteorology & atmospheric sciences
Astronomical unit FOS: Physical sciences Context (language use) 01 natural sciences Spectral line Physics - Space Physics 0103 physical sciences 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences Physics Spectral density estimation Space Physics (physics.space-ph) Computational physics Magnetic field Solar Wind Spectral Analysis Data Recovery Turbulence Solar wind Geophysics Intermediate frequency Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Physics::Space Physics Interpolation |
| Popis: | The Voyager probes are the furthest, still active, spacecraft ever launched from Earth. During their 38-year trip, they have collected data regarding solar wind properties (such as the plasma velocity and magnetic field intensity). Unfortunately, a complete time evolution of the measured physical quantities is not available. The time series contains many gaps which increase in frequency and duration at larger distances. The aim of this work is to perform a spectral and statistical analysis of the solar wind plasma velocity and magnetic field using Voyager 2 data measured in 1979, when the gaps/signal ratio is of order of unity. This analysis is achieved using four different data reconstruction techniques: averages on linearly interpolated subsets, correlation of linearly interpolated data, compressed sensing spectral estimation, and maximum likelihood data reconstruction. With five frequency decades, the spectra we obtained have the largest frequency range ever computed at 5 astronomical units from the Sun; spectral exponents have been determined for all the components of the velocity and magnetic field fluctuations. Void analysis is also useful in recovering other spectral properties such as integral scales (see for instance Table 4) and, if the confidence level of the measurements is sufficiently high, the decay variation in the small scale range due, for instance, to dissipative effects. 11 pages, 7 figures |
| Databáze: | OpenAIRE |
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