Effect of electron inertia on the speed and shape of ion-acoustic solitary waves in plasma

Conditions for the existence of ion-acoustic solitary waves are investigated in a cold collisionless plasma taking into account the electron inertia. The Sagdeev's pseudopotential is derived in terms of u, the ion velocity. It is found that there exists a critical value of u0(≠0), the value of u at which (u')2=0, beyond which the soliton solution ceases to exist and the electron inertia plays a non-insignificant role in determining this critical value. This result reproduces the result of Johnston and Epstein [Phys. Plasmas. 7, 906 (2000)] when the effect of electron inertia is neglected