Coronal heating by the phase mixing of individual pulses propagating in coronal holes

The propagation of Alfvénic pulses into an inhomogeneous model of a coronal hole is investigated. It is demonstrated that the standard exponential damping of a harmonically generated wavetrain, due to phase mixing, is replaced by a slower algebraic damping when individual pulses are considered, suggesting that pulses will transport energy higher into the corona than a wavetrain. In addition, the initial shape of the pulse is rapidly transformed into a travelling Gaussian pulse. When two pulses of opposite sign travelling in the same direction are generated, the pulses diffuse into each other and the decay of the amplitude is faster, although still algebraic.