A discussion on some waves in the plasma comets

The observation already showed that there are a lot of the helical structures, condensations and clouds in the I type plasma cometary tails. The authors have known that they result from the plasma disturbances. In this paper, the authors have given a discussion theoretically, and analysed the evolution processes of non-linear waves as well as their stability in the plasma tails. The Phenomena of the observation in I type tails are able, therefore, to be explained