Cosmic ray transport in partially turbulent space plasmas with
  compressible magnetic turbulence
  Recently a new transport theory of cosmic rays in magnetized space plasmas
extending the quasilinear approximation to the particle orbit has been
developed for the case of an axisymmetric incompressible magnetic turbulence.
Here we generalize the approach to the important physical case of a
compressible plasma. As previously obtained in the case of an incompressible
plasma we allow arbitrary gyrophase deviations from the unperturbed spiral
orbits in the uniform magnetic field. For the case of quasi-stationary and
spatially homogeneous magnetic turbulence we derive in the small Larmor radius
approximation gyro-phase averaged cosmic ray Fokker-Planck coefficients. Upper
limits for the perpendicular and pitch-angle Fokker-Planck coefficients and for
the perpendicular and parallel spatial diffusion coefficients are presented.
