Parallel propagation of ion solitons in magnetic flux tubes

We introduce features of propagating ion-acoustic solitons parallel to the magnetic field lines of magnetic flux tubes. A nonlinear model is used. The model considers both isothermal Boltzmann electrons and finite-temperature warm ions. The electrons are composed of two components, background electrons and energetic ones. A soliton-potential equation is obtained for a generalized oblique magnetic field. With a parameterized numerical study, the effect of several parameters on soliton waves is examined. Results show that the shapes of solitons (density, potential and electric field) depend on the driving potential, Mach number, electron density and the relative temperatures among the ions and electrons. The minimum Mach number of solitons and the effect of the Whistler instability are also discussed.