[A measurement of spontaneous magnetic field by satellites structures of harmonic spectrum].

The satellites structures of doubling harmonic spectrum and tripling harmonic spectrum were measured at the reflection direction of laser wave from the front side of targets, employing OMA optical multi-channel spectrometer during the interactions of femtosecond laser with solid targets. The satellites structures of red-shift harmonic spectrum of 2omega0 and 3omega0 were observed. Under the intensity of approximately 10(18) W x cm(-2), the result of measurement indicates that the spontaneous magnetic field was all less than 1 MGs level by analyzing the satellites structures of doubling harmonic spectrum and tripling harmonic spectrum during the laser-plasma interaction. With increasing the intensity of the laser pulse, the peak of the red-shift moves further to the long wavelength side causing the broadening of the spectrum. The measurements of the spontaneous magnetic field provide a basis of diagnosing the movement of the critical surface in the laser-plasma interaction process.

[Experimental study of soft X-ray radiation in the interaction of circularly polarized femtosecond-laser-pulse with low pressure xenon].

Using flat-field grating Spectrometer, the ions lines with wavelength between 5 and 60 nm were measured, which were produced by the interaction of circularly polarized 35 femtosecond ultraintense and ultrashort laser-pulse with 5 mm length xenon at the pressure 2 and 3 kPa respectively. The highest transition is the XeVIII: 4d10 5s(2 S1/2)--4d9 5s5p('P3/2) line at wavelength 17.0856 nm at 2 kPa and 3 kPa, the highest transition is 11.343 nm line of XeVII 4d10 5s2(1S0)--4d9 5s5f(3P1) transition. The xenon is ionized to XeVII, XeVIII and XeIX at both pressure.

[A measurement of optical emission from the rear surface with solid targets irradiated by ultrashort pulse laser].

The integrated image spectrum and scattering light spectrum of optical emission at normal direction from rear-side of a metallic foil were measured, employing optical CCD camera and OMA optical multi-channel spectrometer. The integrated image spectrum shows that it presents a ring-shape, and in the near margin of the ring-shape a bright localized signal is shown, which is optical transition radiation (OTR) generated by hot electrons transport through solid targets. The scattering spectrum shows that it presents a series of nonperiodic sharp spikes between 300-500 nm, and the sharp spike is ascribed to the coherent transition radiation (CTR) generated by bunches of hot electron beams generated in v x B acceleration mechanism near 400 nm (2 omega). The intensity of transition radiation decreases with the increase of the target thickness.