Wave amplitudes in the solar wind at 1 AU: Implications for energetic particle transport

We use a modified wavelet transformation to analyze ACE MAG data for the rate of occurrence of magnetic fluctuations. We analyze the magnetic field data for amplitude and width of individual waves and obtain distributions of occurring amplitudes and their dependence on the waves frequency and phase. In the analyzed frequency range from 0.0001 to 0.5 Hz we find an exponential distribution of wave amplitudes. The average wave amplitude increases with decreasing frequency and increasing solar activity. We find a significant fraction of large amplitude waves, which do not agree with the assumption of quasilinear theory that the irregularities of the magnetic field are sufficiently small and therefore the changes of an energetic particles pitch angle are also small.