Fig. 7

Probability density function (PDF) of the trace of the magnetic power spectral density matrix. Normalized histograms were obtained from the Survey data measured by the EMFISIS Waves instrument onboard Van Allen Probe A between 14:00 and 17:00 UT on January 1, 2015: (a) channel number²⁹ l = 2, central frequency f_l = 4 Hz, number of averaged power spectra n_l = 1; (b) l = 36, f_l = 397 Hz, n_l = 22; (c) l = 58, f_l = 5011 Hz, n_l = 271, and from the STAFF-SA instrument onboard the Cluster 1 spacecraft between 18:00 and 21:00 UT on March 8, 2002: (d) the 6^th frequency channel with a central frequency of 28 Hz and n_l = 4 averaged spectra; (e) the 13^th channel at 141 Hz and with n_l = 32 averaged spectra; (f) the 24^th channel at 1794 Hz, with n_l = 256 averaged spectra. Blue curves show results of the models based on the scaled \({\chi }^{2}\) distributions²⁴.