Multipoint observation of anisotropy and intermittency in solar-wind turbulence
2015 (English)In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 110, no 1, 19001Article in journal (Refereed) Published
Using high-resolution magnetic-field Cluster observations, we have investigated the magnetic-field anisotropy via the second-and fourth-order structure functions over a wide range of scales reaching below the subproton scale. The magnetic-field increments have been computed from single-and two-spacecraft measurements. The two-satellite technique allows us to study the increments as a function of an actual space lag. Both single-and two-point analyses show that the magnetic field is anisotropic even at small time/spatial scales. The single-spacecraft data also shows that the degree of anisotropy does not change with the scale at proton and subproton scales. It is also pointed out that the degree of magnetic-field anisotropy tends to be overestimated in the single-spacecraft data analysis. This is particularly evident at small scales and it depends on the angle between the spacecraft separation and the flow direction. From the fourth-order moment of the probability density function of the magnetic-field increments we have also investigated the presence of intermittency in the fluctuations. Even though to a different degree, intermittency was present over the entire range of scales, with an indication of scale invariance at subproton scales.
Place, publisher, year, edition, pages
2015. Vol. 110, no 1, 19001
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:uu:diva-257043DOI: 10.1209/0295-5075/110/19001ISI: 000355587200033OAI: oai:DiVA.org:uu-257043DiVA: diva2:828097