Hausdorff Dimension of Typical Very Low Frequency Chorus Emissions and Verification of Their Mechanism of Excitation

Modern mathematical tools are used to perform a quantitative study of the complexity of electromagnetic VLF chorus emissions in the region of their excitation near the local minimum of the magnetic field outside the plasmasphere. Typical examples of chorus are selected for which high-resolution digitized data are available from the vast observational data collected during the Van Allen Probe mission. The original program is used to calculate the Hausdorff dimension of long numerical sequences. In all cases, the dimension is non-integer, testifying to the complex dynamics of the system. Jumps in dimension are noted during the calculations, including a roughly 50% reduction for a fragment of a chorus burst. The obtained results are important for confirming the mechanism of chorus excitation by amplifying short noise pulses and substantiating the automatic identification of different types of electromagnetic radiation.