Oxford Centre for High Energy Density Science (OxCHEDS)

Abstract:

Thomson scattering (TS) measurements are performed at different locations in a laser-produced aluminum plasma. Variations of the separation, wavelength shift, and asymmetric distribution of the two ion-acoustic waves are investigated from their spectral-time-resolved TS images. Detailed information on the space-time evolution of the plasma parameters is obtained. Electron distribution and variation of the heat flux in the plasma are also obtained for a steep temperature gradient.

Abstract:

Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms. © 2005 The American Physical Society.

Abstract:

Here we propose a new diagnostic method for the magnetic field inside an expanding plasma, based on the idea of photon acceleration, or photon frequency shift of radiation coming out of the plasma. Examples of application for laser-target interaction in the Peta-Watt regime, and for intense magnetic fields in astrophysical environments are considered. © 2005 Published by Elsevier B.V.