The FFT dynamic spectrum of a DEMETER IMSC magnetic field record section (25.09.2004 21:29:20 UT). The upper picture is the VLF pattern of the record and the lower picture is the ELF band of same record. In the upper picture several fractional hop whistlers appeared and accompanied to the first fractional-hop (0⁺) whistler appeared the more dispersed second trace of a trapezoid whistler pair. In the lower picture (proton and helium) ion whistlers are also seen where the proton whistler has the higher and the helium whistler has the lower upper frequency asymptote, according to H/He gyro-frequencies.