NONLINEAR-THEORY OF KINETIC ALFVEN WAVES IN A HIGH-PRESSURE PLASMA

A study is made of nonlinear Alfven waves in a uniform high-pressure p lasma with beta much greater than 1 (beta is the ratio of the plasma p ressure to that of the magnetic field). A system of nonlinear equation s is obtained in terms of collisionless hydrodynamics of the Grad type . It is shown that nonlinear, weakly dispersive Alfven waves propagati ng in such a plasma at a large angle to the external magnetic field ca n exist as solitary dipole vortices. A simplified equation for weakly nonlinear Alfven waves is derived from the system of nonlinear equatio ns. The possible existence of nonlocal Alfven-wave turbulence spectra is discussed.