Measurement of spontaneous magnetic field in the interactions of femtosecond laser with solid targets

The experiment measured the fine spectrum structure of 2 doubling harmonic at near normal direction of target and reflection direction of laser wave, employing OMA optical multi-channel spectrometer. Under the intensity of 5×1017W/cm2, the result of measurement indicates that spontaneous magnetic field was up to 102T level by analyzing the fine structure of 2 doubling harmonics in laser-plasma interaction.