Oxford Centre for High Energy Density Science (OxCHEDS)

Abstract:

The temporal coherence properties of the X-ray pulse from a Free Electron Laser (FEL) will be altered during the process of dynamical diffraction from a perfect crystal. We present simulations of this process based on time-dependent dynamical diffraction theory. In addition, we present simulations of the diffraction of chirped X-ray pulses, demonstrating methods of pulse recompression by use of strained crystals.

Abstract:

The present book is a teaching text designed to introduce the fundamentals of thesubject of statistical mechanics.

Abstract:

The possibility of using high-intensity laser-produced plasmas as a source of energetic ions for heavy ion accelerators is addressed. Experiments have shown that neon ions greater than 6 MeV can be produced from gas jet plasmas, and well-collimated proton beams greater than 20 MeV have been produced from highintensity laser solid interactions. The proton beams from the back of thin targets appear to be more collimated and reproducible than are high-energy ions generated in the ablated plasma at the front of the target and may be more suitable for ion injection applications. Lead ions have been produced at energies up to 430 MeV. © 2000 IEEE.

Abstract:

We present results from three-dimensional numerical simulations investigating the magnetohydrodynamics of cloud-wind interactions. The initial cloud is spherical, while the magnetic field is uniform and transverse to the cloud motion. A simplified analytical model that describes the magnetic energy evolution in front of the cloud is developed and compared with simulation results. In addition, it is found that the interaction of the cloud with a magnetized interstellar medium results in the formation of a highly structured magnetotail. The magnetic flux in the wake of the cloud organizes into flux ropes, and a reconnection current sheet is developed as field lines of opposite polarity are brought close together near the symmetry axis. At the same time magnetic pressure is strongly enhanced at the leading edge of the cloud from the stretching of the field lines that occurs there. This has an important dynamical effect on the subsequent evolution of the cloud, since some unstable modes tend to be strongly enhanced.