RESUMO
The peak power and temporal intensity contrast of powerful femtosecond laser pulses were enhanced simultaneously by broadening the pulse spectrum in transparent dielectrics due to self-phase modulation and subsequent reflection from chirping mirrors with a symmetrical dip in the reflection coefficient in the center of the broadened spectrum. This dip provides almost zero reflection of the pulse pedestal, only slightly distorting the pulse itself.
RESUMO
An up to 15 T pulsed magnetic field generator in a volume of a few cubic centimeters has been developed for experiments with magnetized laser plasma. The magnetic field is created by a pair of coils placed in a sealed reservoir with liquid nitrogen, installed in a vacuum chamber with a laser target. The bearing body provides the mechanical strength of the system both in the case of co-directional and oppositely connected coils. The configuration of the housing allows laser radiation to be introduced into the working area between the coils in a wide range of directions and focusing angles, places targets away from the symmetry axis of the magnetic system, and irradiates several targets simultaneously.
RESUMO
The laser wakefield acceleration electron beams can essentially deviate from the axis of the system, which distinguishes them greatly from beams of conventional accelerators. In case of energy measurements by means of a permanent-magnet electron spectrometer, the deviation angle can affect accuracy, especially for high energies. A two-screen single-shot electron spectrometer that correctly allows for variations of the angle of entry is considered. The spectrometer design enables enhancing accuracy of measuring narrow electron beams significantly as compared to a one-screen spectrometer with analogous magnetic field, size, and angular acceptance.