Dynamics of broadband dispersive Alfven waves
  The properties of amplitude modulated broadband Alfven waves is investigated. In particular, the dynamics of circularly polarized dispersive Alfven waves, governed by a derivative nonlinear Schroedinger equation, is analyzed using the Wigner formalism. The modulational instability of random phase dispersive pump Alfven waves is investigated, and it is shown that the spectral broadening gives rise to a new mode structure. 
M. Marklund and P. K. Shukla