Wide Solitons in an Ion-Beam-Plasma System

Solitons are experimentally found in a double plasma device when an ion beam is present with beam velocity {ital v}{sub {ital b}} in the range 1{le}{ital v}{sub {ital b}}/{ital c}{sub {ital s}}{le}2.2, where {ital c}{sub {ital s}} is the ion acoustic velocity. These one dimensional solitons have an unusually large width (parallel to the direction of propagation) {ital W}{approx_equal}14{lambda}{sub {ital D}}({delta}{ital n}/{ital n}){sup {minus}1/2}, where {lambda}{sub {ital D}} is the Debye length and {delta}{ital n}/{ital n} is the maximum normalized density fluctuation. The amplitude, width, and velocity characteristics of the solitons are found to be in good agreement with the soliton solution to the Korteweg{endash}de Vries equation in an ion-beam{endash}plasma system. {copyright} {ital 1996 The American Physical Society.}