Methods for Characterising Microphysical Processes in Plasmas

Wit, T. Dudok de; Alexandrova, Olga; Furno, I.; Sorriso‐Valvo, L.; Zimbardo, G.

doi:10.1007/978-1-4899-7413-6_21

Cited by 6 publications

(9 citation statements)

References 26 publications

(22 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These figures present the structure functions up to order 6 (the analysis of higher orders is not statistically significant, Dudok de Wit et al. 2013). For analysis of the higher orders of the structure functions, we atempt to use longer intervals than we have used for the analysis of the spectra.…”

Section: Statistical Properties Of Turbulence For Different Shapes Ofmentioning

confidence: 99%

Variety of shapes of solar wind ion flux spectra: Spektr-R measurements

et al. 2017

View full text Add to dashboard Cite

The paper is devoted to the shapes of the solar wind ion flux fluctuation spectrum at the transition between the inertial and the kinetic range using in situ high-resolution measurements of the Russian mission Spektr-R. We analyse the variability of the transition region and select five typical types of spectral shapes: (i) spectra with two slopes and one break, (ii) spectra characterized by a nonlinear steepening in the kinetic range, (iii) spectra with flattening in the vicinity of the break, (iv) spectra with a bump in the vicinity of the break and (v) spectra without any steepening in the kinetic range. The most popular is the well-known type (i) observed in approximately half of the cases. The second most popular type of spectra is type (iii) occurring in approximately one third of the cases. The other three types are observed less often: type (ii) – in approximately 6 %; type (iv) in 3 % and type (v) in 6 % of cases. An analysis of typical plasma conditions for different types of spectra revealed that the last two type of spectra (iv) and (v) are generally observed in a very slow solar wind with a low proton density, (i) and (iii) are observed in the solar wind with rather typical conditions and (ii) is usually observed in high-speed streams. The effect of nonlinear steepening of the spectra in the kinetic range increases with the solar wind speed. We present also the analysis of statistical properties of the observed events and compare them with the predictions of several statistical turbulence models. We show that intermittency is always observed in the solar wind flow despite the presence of one or another shape of spectra. The log-Poisson model with a dominant contribution of filament-like structures shows the best parameterization of the experimentally observed scaling.

show abstract

Section: Statistical Properties Of Turbulence For Different Shapes Ofmentioning

confidence: 99%

Variety of shapes of solar wind ion flux spectra: Spektr-R measurements

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The level of intermittency as a function of τ can be quantified using a calculation of the flatness defined as [27]…”

Section: Pdfsmentioning

confidence: 99%

Turbulence analysis of an experimental flux-rope plasma

Schaffner¹,

Lukin²,

Wan³

et al. 2014

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Abstract. We have previously generated elongated Taylor double-helix flux rope plasmas in the SSX MHD wind tunnel. These plasmas are remarkable in their rapid relaxation (about one Alfvén time) and their description by simple analytical Taylor force-free theory despite their high plasma β and high internal flow speeds. We report on the turbulent features observed in these plasmas including frequency spectra, autocorrelation function, and probability distribution functions of increments. We discuss here the possibility that the turbulence facilitating access to the final state supports coherent structures and intermittency revealed by non-Gaussian signatures in the statistics. Comparisons to a Hall-MHD simulation of the SSX MHD wind tunnel show similarity in several statistical measures.

show abstract

“…1995 a ; Van Milligen, Hidalgo & Sanchez 1995 b ; Dudok De Wit et al. 2014), intermittency (Carbone et al. 2000) and anisotropy (Alexandrova, Lacombe & Mangeney 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Let us only mention a few references of wavelet techniques that have been used to analyse and quantify plasma turbulence: e.g. transients (Dose, Venus & Zohm 1997), bicoherence (Dudok De Wit & KrasnoselSkikh 1995;Van Milligen et al 1995a;Van Milligen, Hidalgo & Sanchez 1995b;Dudok De Wit et al 2014), intermittency (Carbone et al 2000) and anisotropy (Alexandrova, Lacombe & Mangeney 2008). An exhaustive review is beyond the scope of our paper and we focus here exclusively on our contributions.…”

Section: Introductionmentioning

confidence: 99%

Wavelet transforms and their applications to MHD and plasma turbulence: a review

Farge

Schneider

2015

J. Plasma Phys.

View full text Add to dashboard Cite

International audienceWavelet analysis and compression tools are reviewed and different applications to study MHD and plasma turbulence are presented. We introduce the continuous and the orthogonal wavelet transform and detail several statistical diagnostics based on the wavelet coefficients. We then show how to extract coherent structures out of fully developed turbulent flows using wavelet-based denoising. Finally some multiscale numerical simulation schemes using wavelets are described. Several examples for analyzing, compressing and computing one, two and three dimensional turbulent MHD or plasma flows are presented

show abstract

Methods for Characterising Microphysical Processes in Plasmas

Cited by 6 publications

References 26 publications

Variety of shapes of solar wind ion flux spectra: Spektr-R measurements

Variety of shapes of solar wind ion flux spectra: Spektr-R measurements

Turbulence analysis of an experimental flux-rope plasma

Wavelet transforms and their applications to MHD and plasma turbulence: a review

Contact Info

Product

Resources

About