2 research outputs found
About the parabolic relation existing between the skewness and the kurtosis in time series of experimental data
In this work we investigate the origin of the parabolic relation between
skewness and kurtosis often encountered in the analysis of experimental
time-series. We argue that the numerical values of the coefficients of the
curve may provide informations about the specific physics of the system
studied, whereas the analytical curve per se is a fairly general consequence of
a few constraints expected to hold for most systems.Comment: To appear in Physica Script
On the statistics of edge fluctuations: comparative study between various fusion devices
In this paper we present a statistical study of edge fluctuations taken with
the Gas Puffing Imaging (GPI) diagnostics. We carry out a comparison of GPI
signal from an extensive database including four devices (two Tokamaks and two
Reversed Field Pinches). The data are analyzed in terms of their statistical
moments Skewness and Kurtosis, as done in [B. Labit, et al, Phys. Rev. Lett.
\textbf{98}, 255002 (2007)]. The data align along parabolic curves, although
different from machine to machine, with some spread around the best-fitting
curve. A discussion about the meaning of the parabolic trend as well as the
departure of real data from it is provided. A phenomenological model is finally
provided, attempting to accomodate experimental evidence.Comment: To appear in Plasma Physics and Controlled Fusio