A novel method for detection of strong magnetic fields in femtosecond laser-matter interaction

Femtosecond laser-matter interaction can produce strongly magnetized dense plasmas via ultrafast ionization process. This paper proposes a diagnostic- which is not yet existing as far as we know-to prove the existence and to m easure the strength of the quasistatic magnetic field in overdense plasma w here the Faraday rotation method is not applicable. The method is based on the analysis of the propagation of a quasi-longitudinal right circular pola rized electromagnetic probe wave, i.e., a whistler wave. The method is appl icable when the quasistatic magnetic field is strong enough (some tens of m egagauss) and the overdense plasma electron density not too high (n(e)less than or equal to 5x10(22) cm(-3)). (C) 2000 American Institute of Physics. [S1070-664X(00)05307-6].