The acceleration of energetic particles by transit-time damping

Recently, the quasilinear transport and acceleration parameters for cosmic ray particles interacting with oblique propagating fast magnetosonic waves, in a small-p plasma, have been calculated anew, using a linear wave dispersion relation. Including the dispersive part in the wave dispersion relation, we improve the quasilinear calculation of the transit-time damping acceleration time. We find that, if the turbulence spectrum extends to sufficiently high wavenumbers, the efficiency of the process of acceleration by the fast magnetosonic branch is significantly enhanced for electrons below 10(3)V(A)/C MeV, making this process a good candidate for injection. (C) 1998 Elsevier Science B.V.