Multiscale structure of the magnetic field and speed at 1 AU during the declining phase of solar cycle 23 described by a generalized Tsallis probability distribution function -: art. no. A12107

This paper describes the multiscale structure of fluctuations in the solar wind speed V and magnetic field strength B at 1 AU in 2003, during the declining phase of the solar cycle 23. As expected, there was a corotating stream and a corotating interaction region (CIR) that recurred every 27 days, but the stream and CIR changed considerably from one solar rotation to the next. There were also other types of physical structures ( intermittent turbulence at the smallest scales, compound streams and ejecta at intermediate scales, and the collection of streams and ejecta of different sizes and shapes at the largest scales). A multiscale description of these fluctuations is more appropriate than a model of a recurrent stream with small-scale fluctuations superimposed. The probability distribution functions (PDFs) of changes of V and B on scales from 1 hour to approximate to171 days can be described by a generalization of the PDF derived by Tsallis from a nonadditive entropy function in the context of nonextensive statistical mechanics.