Fig. 1
From: Software-type Wave–Particle Interaction Analyzer on board the Arase satellite
Schematic diagram of the S-WPIA for measuring interactions between energetic electrons and whistler-mode waves propagating purely parallel to the background magnetic field (after Katoh et al. 2013). Panels a and b represent the relation between the perpendicular component of the velocity vector of an electron (v⊥) and the wave electric (Ew) and magnetic (Bw) field vectors in the cases of a W < 0 and b W > 0. c Distribution of energetic electrons as a function of W, corresponding to a negative Wint case representing wave generation. The total number of energetic electrons is N0, while N+ and N− are the numbers of energetic electrons having positive and negative W, respectively