Suppression effects of Weibel instability for fast electron divergence

Abstract

Quasi-static magnetic fields, which are induced by the Weibel instability and grow to more than hundred Megagauss, lead to large divergence angle of fast electrons, hence lower energy coupling. To suppress the divergence, two different structures, namely density trough and punched out holes, are introduced to targets. In the density trough target, the Weibel instability is enhanced and the divergence is getting worse. On the other hand, the divergence angle is improved but the number of electrons is degraded for fast electrons (<3 MeV) in the punched out target.