An experiment is being conducted using two plasma streams with opposing velocities in a transverse magnetic field to observe the interaction of the two opposing polarization electric fields. The technique is a possible emans of loading a clased-field geometry. The two similar streams are not directly opposed but are displaced from one another along the magnetic field to increase the possibility of a significant interaction. The fast plasma produced by coaxial guns has a density up to 5 x 104 cm−3 and a directed velocity of 50 to 70 cm/[mu]sec. The resultant polarization field in kilogauss magnetic fields is of the order of kilovolts percentimeter. The lateral stream separation is 54 cm, and at magnetic fields below 3.0 kG the streams have a negligible effect on each other. At high fields (7.0 kG), the streams have a larger interaction under certain conditions, and an increase in density is observed. The effects when two streams differ widely in density and arrival time are discussed.

These proceedings are based upon introductory talks, research reports and discussions from the NATO Advanced Workshop on the "Morphology and Dynamics of the Polar Cusp", held at Lillehammer, Norway, 7-12 May, 1984. The upper atmosphere at high latitudes is called the "Earth's win dow to outer space". Through various electrodynamic coupling process es as well as through direct transfer of particles many geophysical effects displayed there are direct manifestations of phenomena occurring in the deep space. The high latitude ionosphere will also exert a feedback on the regions of the magnetosphere and atmosphere to which it is coupled, acting as a momentum and energy source and sink, and a source of particles. Of particular interest are the sections of the near space known as the Polar Cusp. A vast portion of the earth's magnetic field envelope is electrically connected to these regions. This geometry results in a spatial mapping of the magnetospheric pro cesses and a focusing on to the ionosphere. In the Polar Cusps the solar wind plasma has also direct access to the upper atmosphere. The polar regions are thus of extreme importance when it comes to under standing the physical processes in the near space and their effect on our environment. The Introductory Talks given at this workshop provided a common background for discussing and understanding the physics of the Polar Cusp. By this book we will make the information which thus was provid ed to the participants of the workshop accessible to a wider audience.

Filling the need for a book bridging the effect of matter on X-ray radiation and the interaction of x-rays with plasmas, this monograph provides comprehensive coverage of the topic. As such, it presents and explains such powerful new X-ray sources as X-ray free-electron lasers, as well as short pulse interactions with solids, clusters, molecules, and plasmas, and X-ray matter interactions as a diagnostic tool. Equally useful for researchers and practitioners working in the field.