The propagation of ion-acoustic solitons in a plasma with negative ions has been investigated experimentally. At a critical concentration of negative ions, both compressive and rarefactive solitons are observed. The velocity and the width of the solitons are measured and compared with the soliton solution of the modified Korteweg-de Vries equation.

• Received 13 April 1984

DOI:https://doi.org/10.1103/PhysRevLett.52.2356