Possible spectroscopic signature of wave collapse in edge plasmas

In plasmas coupled to an external energy source like a beam of energetic electrons, one can observe the non-linear coupling of Langmuir waves with ion sound and electromagnetic waves. This non-linear interaction of waves changes the structural and radiative properties of plasmas. Coherent wave packets are trapped in regions of high intensity, and are subjected to a wave collapse cycle. We show that the electric field of the wave packets can modify the spectral lines emitted by hydrogen atoms. Our model for this field is a sequence of envelope solitons oscillating at the plasma frequency or the upper hybrid frequency. The calculations presented concern the H and H Balmer lines of hydrogen and show the possible modifications of the line shapes if wave collapse conditions affect the edge plasma.