Structure Formation and Tearing of an MeV Cylindrical Electron Beam in a Laser-Produced Plasma

The stability of a cylindrical, solid hot electron beam propagating in a high density plasma has been studied using a two-dimensional, hybrid Darwin code. The initially solid beam evolves into a hollow, annular beam due to the Weibel instability and generates strong magnetic fields on both sides of the annular ring. The annular structure subsequently breaks up into several beamlets via a mechanism similar to a tearing instability. It is found that the magnetic fields parallel to the direction of beam propagation also grow due to the tearing process.