Self Generated Magnetic Field in a Laser Produced Plasma Embedded with Atomic Clusters

Self generated magnetic field by an amplitude modulated intense laser beam in a tunnel ionized inhomogeneous plasma embedded with atomic clusters is studied. The transverse profile of the laser (along y ˆ ) is cosine and the clusters are taken to undergo Coulomb explosion thereby creating a plasma with decreasing density with time. The laser exerts a ponderomotive force F → p on the electrons, imparting them a transverse velocity v → . The current density J → , thus produced is irrotational i.e. ∇ × J → ≠ 0 , and gives rise to a quasistatic magnetic field along F → p × ∇ n 0 . The generated magnetic field amplitude is sensitive to electron plasma frequency and laser modulation frequency. The peak value of generated magnetic field at resonance is ~40 MGauss at laser intensity 10 15 W/cm 2 .