Stability of ion acoustic nonlinear waves and solitons in magnetized   plasmas
  Early results concerning the shape and stability of ion acoustic waves are generalized to propagation at an angle to the magnetic field lines. Each wave has a critical angle for stability. Known soliton results are recovered as special cases. A historical overview of the problem concludes the paper. 
Piotr Goldstein and Eryk Infeld
nlin.PS math-ph math.AP math.MP