Large Mach number ion acoustic rarefactive solitary waves for a two electron temperature warm ion plasma

An exact analytical form of Sagdeev pseudopotential has been derived for a two electron temperature warm ion plasma, from which ion acoustic rarefactive solitary wave solutions could be investigated for a wide range of different plasma parameters, viz., ion temperature (σ), cold to hot electron temperature ratio (β), and initial cold electron concentration (μ). Explicitly large Mach numbers have been obtained for increasing hot to cold electron temperature ratios, and an analytical condition for the upper bound of the Mach number has been derived for such a rarefactive solitary wave. It is found that the width of these waves obey Korteweg–de Vries soliton-type behavior only for small amplitudes (i.e., eφ/Teff<1) while for large amplitudes, the width of the rarefactive solitary waves increases with increasing amplitude.