STABILITY OF A RELATIVISTIC ROTATING ELECTRON-POSITRON JET

In the force-free approximation, an electron-Positron jet is shown to be stable to axisymmetric perturbations for all velocities of longitudinal motion and rotation. The stability of the 'et is a result of the shear of the magnetic field, which prohibits the convective motion of a charged fluid in the radial direction. The dispersion curves omega = omega(k(parallel-to)) have a minimum for k(parallel-to 0) congruent-to 1/R, where R is the jet radius. This results in the accumulation of perturbations inside the jet with wavelengths of the order of the jet radius. This type of oscillatory structure is observed in kiloparsec jets, in particular in 3C 273, which is evidently an electron-positron beam.