Langmuir Solitons and Ion-Sound

Abstract

I want to report here on some work from our group at Oxford, mainly by John Gibbons, Steve Thornhill, and Martin Wardrop, details of which can be found in a forthcoming paper (Gibbons, Thornhill, Wardrop and ter Haar 1976). We have in Oxford for some time been interested in various manifestations of plasma effects in astrophysics. Due to the enormous amounts of energy available, it is likely that many astrophysical objects, such as pulsar magnetospheres, accretion discs, galactic nuclei, quasars, and supernova remnants may contain turbulent plasmas. One way to approach this problem was the introduction by Tsvtovich and Chikhachev of plasma turbulent reactors (for a review of their theory see Norman and ter Haar 1975), but it now appears that these systems — at least in the simplified form in which they have been considered so far — are not adequate. It was therefore felt advisable to see whether one might find a theory of plasma turbulence which could easily be built into astrophical theory. The work by Kingsep, Rudakov, and Sudan (1973) sugested that perhaps a strongly Langmuir-turbulent plasma might be..lescribed as a gas of Langmuir solitons. This was the reason for a programme for studying the properties of Langmuir solitons and I am presenting some of the results of this programme, I should perhaps add that we are no longer very optimistic about the soliton approach to strong turbulence.