STORM - Solar system plasma Turbulence:  Observations, inteRmittency and Multifractals

D1MAXSW (1999-2001) - a database of spectral power, probability density and multifractal analysis of solar wind data at solar maximum

 This database provides results of solar wind data analysis from Ulysses (1999-2001) and Cluster (2000-2001) and includes three catalogues of analyzed data as shown below:

  1. D1MAXSW_1999_2001_PSD - A catalogue of spectral analysis of solar wind data from Ulysses and Cluster between 1999 and 2001; it includes 510 PSD spectra (295 spectra from Ulysses, 215 spectra from Cluster).
  2. D1MAXSW_1999_2001_PDF - A catalogue of Probability distribution functions computed for magnetic fluctuations recorded  in the solar wind by Ulysses and Cluster between 1999 and 2001; it includes 546 PDFs (340 from Ulysses, 206 from Cluster).
  3. D1MAXSW_1999_2001_Multifractals - A catalogue of multifractal spectra (computed with Partition Function and Rank Ordered methods) of magnetic fluctuations recorded in the solar wind by Ulysses and Cluster between 1999 and 2001. It includes 289 multifractal partition function spectra (151 spectra for fast SW, 138 spectra for slow SW) and 240 ROMA spectra (43 spectra for fast SW, 197 spectra for slow SW).

The two archives D1MAXSW_1999_2001_PSD and D1MAXSW_1999_2001_PDF have a similar structure as ilustrated by the diagram inserted below. The results are organized as a function of mission and type of wind. The procedure to determine the state of the wind (fast or slow) is based on a complex of five differente parameters (Wawrzaszek et al., ApJL, 2015) for Ulysses and on solar wind bulik speed for Cluster (threshold bulk speed is equal to 450 km/s). The two archves include image files (.png) and the corresponding binary files (.txt) for PSDs and PDFs computed for solar wind data from Cluster 1, Cluster 3 and Ulysses. The name of files are self explanatory, indicate the type of wind, the spacecraft and the data of observations, as illustrated by the example included in the diagram below.


Two samples of a PSD spectrum (at left) and a PDF computed for four different scales (at right) are illustrated below; they were computed from the radial component of the magnetic field measured by Ulysses during a fast solar wind stream selected in the D1MAXSW catalogue.

(Top) Raw data (the radial component, BR, of the interplanetary magnetic field) on which the spectral analysis is applied; (middle) the normalized data (the average is subtracted and the signal is divided by the variance; (lower) the PSD spectrum computed with the Welch algorithm.)   (top) the Radial component (BR) of the interplanetary magnetic field measured by Ulysses in a fast solar wind stream; (bottom) the probability distribution function computed for BR and four different scales; a Gaussian profile is added in red.

The structure of the archive D1MAXSW_1999_2001_Multifractals is illustrated by the diagram included below. We provide two types of multifractal spectra:(1) the partition function multifractal spectra (for a description see, e.g., Wawrzaszek et al., ApJL, 2015) and the Rank  Ordered Multifractal Analysis (ROMA, for a description see; e.g. Chang et al., 2011). The results are grouped as a function of spacecraft and type of wind (fast versus slow). As a difference with respect to PSD and PDF archives we notice that multifractal spectra from Cluster 1 and Cluster 3 are collected in the same directory.

An example of a multifractal spectrum computed with the partition function approach is included below. It shows the multifractal properties (expressed by the f(a) spectrum) of the fluctuations of the radial component of the interplanetary magnetic field measured by Ulysses in the fast solar wind.

Example of a multifractal spectrum (f(a)) extracted from the D1MAXSW catalogue. The upper panel shows the analyzed signal (the region highlighted in blue indicates the interval of convergence); the lower panel shows the multifractal spectrum (with blue diamonds) and two fit based on turbulence models (the p-model in red, and the modified two-sclae Cantor set in blue).