Dependence of pitch angle scattering of cosmic rays on slope of power spectra of magnetic field fluctuations in interplanetary space

Slope of magnetic field power spectrum and particles rigidity dependence of histogram of H(μ) as a function of μ (=pitch-angle cosine) have been intensively studied by using Monte Carlo pitch-angle scattering technique. In calculation, slab model with transverse (x, y) field fluctuations varying only the average field direction (z) is adapted. Our analysis shows that big hump of scattering coefficient (D(μ)) around μ=0.0 obtained by other workers can be largely reduced by injecting test particles with μsub(s)=0.0, where μsub(s) is the injection point of pitch-angle cosine. The D(μ) obtained thus is nearly approximated by quasi linear theory for γ>=2.0 and for γ<=1.7, there is a considerable diffusion through μ=0.0 although our D(μ) around μ=0.0 is much smaller