Generation of Quasistatic Magnetic Field in the Relativistic Laser-Plasma Interactions

The magnetic field generation by a relativistic laser light irradiated on a thin target at the oblique incidence is investigated using a two dimensional particle-in-cell simulation. Three kinds of quasistatic magnetic fields, which are located at the front surface, inner plasma, and rear surface, are found. First magnetic field which is located on a front surface arises very quickly, of which raising time is almost the same of the laser raising time. Second magnetic field is gradually growth in a inner plasma by the Weibel instability, which occurs between the fast electrons generated by the vacuum heating and their return currents. Final magnetic field that is located on the rear surface of the thin target arises also very quickly when electrons pass through the surface and return into the plasma. Keywords: relativistic laser, magnetic field generation, surface magnetic field, relativistic laser-plasma, Weibel instability, vacuum heating 1