Trapping of plasmons in ion holes

We present analytical and numerical studies of a new electron plasma wave interaction mechanism which reveals trapping of Langmuir waves in ion holes associated with non-isothermal ion distribution functions. This Langmuir-ion hole interaction is a unique kinetic phenomenon, which is governed by two second nonlinear differential equations in which the Langmuir wave electric field and ion hole potential are coupled in a complex fashion. Numerical analyses of our nonlinearly coupled differential equations exhibit trapping of localized Langmuir wave envelops in the ion hole which is either standing or moving with sub- or super ion thermal speed. The resulting ambipolar potential of the ion hole is essentially negative, giving rise to bipolar slow electric fields. The present investigation thus offers a new Langmuir wave contraction scenario that has not been rigorously explored in plasma physics.