Abstract
Abstract While low-frequency plasma fluctuations in the interplanetary space have been successfully described in the framework of classical turbulence, high-frequency fluctuations still represent a challenge for theoretical models. At these scales, kinetic plasma processes are at work, but although some of them have been identified in spacecraft measurements, their global effects on observable quantities are sometimes not fully understood. In this paper we present a new framework to the aim of describing the observed magnetic energy spectrum and directly identify in the data the presence of Landau damping as the main collisionless dissipative process in the solar wind.
Highlights
Nonlinear interactions and turbulence play a key role in determining the evolution of several astrophysical plasma systems (Coleman 1968; Scalo & Elmegreen 2004; Zhuravleva et al 2014; Cranmer et al 2015; Bruno & Carbone 2016)
Due to its proximity to the Earth, the Solar Wind, namely the collisionless plasma coming from the expanding solar corona which pervades the interplanetary space, represents a unique natural laboratory to study turbulence and all the microphysical plasma processes related to the transfer of energy from the turbulent electromagnetic field to the plasma particles (Goldstein et al 2015; Bruno & Carbone 2016; Chen 2016)
The random forcing is expressed as dW(t) = ξ(t)dt, which is a suitable physical choice for an interpretation of ξ(t) as real noise, possibly different from white noise, with finite correlation times (Gardiner 2009)
Summary
Nonlinear interactions and turbulence play a key role in determining the evolution of several astrophysical plasma systems (Coleman 1968; Scalo & Elmegreen 2004; Zhuravleva et al 2014; Cranmer et al 2015; Bruno & Carbone 2016). In such cases, energy is injected at large scales and cascades to microscales where it is dissipated, heating the medium. The magnetic energy spectrum scaling observed in the frequency domain ω is in good agreement with the Kolmogorov law E(k) ∼ k−5/3 (Bruno & Carbone 2016) once
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