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Statistical properties of the interplanetary magnetic field fluctuations can provide an important insight into the solar wind turbulent cascade. Recently, analysis of the Probability Density Functions (PDF) of the velocity and magnetic field fluctuations has shown that these exhibit nonGaussian properties on small time scales while large scale features… (More)

- Bogdan Hnat, Sandra C Chapman, George Rowlands
- Physical review. E, Statistical, nonlinear, and…
- 2003

The solar wind provides a natural laboratory for observations of magnetohydrodynamic (MHD) turbulence over extended temporal scales. Here, we apply a model independent method of differencing and rescaling to identify self-similarity in the probability density functions (PDF) of fluctuations in solar wind bulk plasma parameters as seen by the WIND… (More)

- K Kiyani, S C Chapman, B Hnat
- Physical review. E, Statistical, nonlinear, and…
- 2006

We address the generic problem of extracting the scaling exponents of a stationary, self-affine process realized by a time series of finite length, where information about the process is not known a priori. Estimating the scaling exponents relies upon estimating the moments, or more typically structure functions, of the probability density of the… (More)

- Bogdan Hnat, Sandra C Chapman, George Rowlands
- Physical review letters
- 2005

Incompressible magnetohydrodynamics is often assumed to describe solar wind turbulence. We use extended self-similarity to reveal scaling in the structure functions of density fluctuations in the solar wind. The obtained scaling is then compared with that found in the inertial range of quantities identified as passive scalars in other turbulent systems. We… (More)

- K Kiyani, S C Chapman, B Hnat, R M Nicol
- Physical review letters
- 2007

We quantify the scaling of magnetic energy density in the inertial range of solar-wind turbulence seen in situ at 1 AU with respect to solar activity. At solar maximum, when the coronal magnetic field is dynamic and topologically complex, we find self-similar scaling in the solar wind, whereas at solar minimum, when the coronal fields are more ordered, we… (More)

Mandelbrot introduced the concept of fractals to describe the nonEuclidean shape of many aspects of the natural world. In the time series context he proposed the use of fractional Brownian motion (fBm) to model non-negligible temporal persistence, the “Joseph Effect”; and Lévy flights to quantify large discontinuities, the “Noah Effect”. In space physics,… (More)

- K T Osman, W H Matthaeus, K H Kiyani, B Hnat, S C Chapman
- Physical review letters
- 2013

The first observed connection between kinetic instabilities driven by proton temperature anisotropy and estimated energy cascade rates in the turbulent solar wind is reported using measurements from the Wind spacecraft at 1 AU. We find enhanced cascade rates are concentrated along the boundaries of the (β∥, T⊥/T∥) plane, which includes regions theoretically… (More)

- K T Osman, W H Matthaeus, B Hnat, S C Chapman
- Physical review letters
- 2012

A connection between kinetic processes and intermittent turbulence is observed in the solar wind plasma using measurements from the Wind spacecraft at 1 A.U. In particular, kinetic effects such as temperature anisotropy and plasma heating are concentrated near coherent structures, such as current sheets, which are nonuniformly distributed in space.… (More)

- B Hnat, S C Chapman, G Gogoberidze, R T Wicks
- Physical review. E, Statistical, nonlinear, and…
- 2011

The higher-order statistics of magnetic field magnitude fluctuations in the fast quiet solar wind are quantified systematically, scale by scale. We find a single global non-Gaussian scale-free behavior from minutes to over 5 h. This spans the signature of an inertial range of magnetohydrodynamic turbulence and a ~1/f range in magnetic field components. This… (More)