A new computational method and algorithm, based on complex Fourier ana
lysis, is used to derive the spectral density of plane and circularly
polarized fluctuation components of the interplanetary magnetic field.
Applications of the method have been made using HEOS 2 (1 AU), Pionee
r 10 (5 AU), Pioneer 11 (20 AU), and ICE (Giocabini-Zinner's comet) da
ta sets. The results show the existence of circularly polarized MHD wa
ves in all cases.