On the scaling features of magnetic field fluctuations at non-MHD scales in turbulent space plasmas

[摘要] In several different contexts space plasmas display intermittent turbulence at magneto-hydro-dynamic (MHD) scales, which manifests in anomalous scaling features of the structure functions of the magnetic field increments. Moving to smaller scales, i.e. below the ion-cyclotron and/or ion inertial length, these scaling features are still observed, even though its is not clear if these scaling features are still anomalous or not. Here, we investigate the nature of scaling properties of magnetic field increments at non-MHD scales for a period of fast solar wind to investigate the occurrence or not of multifractal features and collapsing of probability distribution functions (PDFs) using the novel Rank-Ordered Multifractal Analysis (ROMA) method, which is more sensitive than the traditional structure function approach. We find a strong evidence for the occurrence of a near mono-scaling behavior, which suggests that the observed turbulent regime at non-MHD scales mainly displays a mono-fractal nature of magnetic field increments. The results are discussed in terms of a non-compact fractal structure of the dissipation field.

[发布机构] INAF-Istituto di Astrofisica e Planetologia Spaziali, Roma, Italy^1;Swedish Institute for Space Physics, Uppsala, Sweden^2;Space Research Institute, Austrian Academy of Sciences, Graz, Austria^3;Belgian Institute for Aeronomy, Brussels, Belgium^4;Institute for Space Sciences, Magurele, Romania^5;Kavli Institute for Astrophysics and Space Research, MIT, Cambridge; MA, United States^6

[效力级别] 天文学 [学科分类] 天文学(综合)

[关键词] Dissipation fields;Fractal structures;Ion inertial length;Magnetic field fluctuations;Multifractal analysis;Scaling properties;Structure functions;Traditional structures