Lasers with a gaseous active medium offer high flexibility, wide tunability, and advantages in cost, beam quality, and power scalability. Gas lasers have tended to become overshadowed by the recent popularity and proliferation of semiconductor lasers. As a result of this shift in focus, details on modern developments in gas lasers are difficult to find. In addition, different types of gas lasers have unique properties that are not well-described in other references. Collecting expert contributions from authorities dealing with specific types of lasers, Gas Lasers examines the fundamentals, current research, and applications of this important class of laser. It is important to understand all types of lasers, from solid-state to gaseous, before making a decision for any application. This book fills in the gaps by discussing the definition and properties of gaseous media along with its fluid dynamics, electric excitation circuits, and optical resonators. From this foundation, the discussion launches into the basic physics, characteristics, applications, and current research efforts for specific types of gas lasers: CO lasers, CO2 lasers, HF/DF lasers, excimer lasers, iodine lasers, and metal vapor lasers. The final chapter discusses miscellaneous lasers not covered in the previous chapters. Collecting hard-to-find material into a single, convenient source, Gas Lasers offers an encyclopedic survey that helps you approach new applications with a more complete inventory of laser options.

These proceedings collect the papers presented at the 30th International Symposium on Shock Waves (ISSW30), which was held in Tel-Aviv Israel from July 19 to July 24, 2015. The Symposium was organized by Ortra Ltd. The ISSW30 focused on the state of knowledge of the following areas: Nozzle Flow, Supersonic and Hypersonic Flows with Shocks, Supersonic Jets, Chemical Kinetics, Chemical Reacting Flows, Detonation, Combustion, Ignition, Shock Wave Reflection and Interaction, Shock Wave Interaction with Obstacles, Shock Wave Interaction with Porous Media, Shock Wave Interaction with Granular Media, Shock Wave Interaction with Dusty Media, Plasma, Magnetohyrdrodynamics, Re-entry to Earth Atmosphere, Shock Waves in Rarefied Gases, Shock Waves in Condensed Matter (Solids and Liquids), Shock Waves in Dense Gases, Shock Wave Focusing, Richtmyer-Meshkov Instability, Shock Boundary Layer Interaction, Multiphase Flow, Blast Waves, Facilities, Flow Visualization, and Numerical Methods. The two volumes serve as a reference for the participants of the ISSW30 and anyone interested in these fields.

The prospects for realizing a magnetohydrodynamic (MHD) bypass hypersonic airbreathing engine are examined from the standpoint of fundamental thermodynamic feasibility. The MHD-bypass engine, first proposed as part of the Russian AJAX vehicle concept, is based on the idea of redistributing energy between various stages of the propulsion system flow train. The system uses an MHD generator to extract a portion of the aerodynamic heating energy from the inlet and an MHD accelerator to reintroduce this power as kinetic energy in the exhaust stream. In this way, the combustor entrance Mach number can be limited to a specified value even as the flight Mach number increases. Thus, the fuel and air can be efficiently mixed and burned within a practical combustor length, and the flight Mach number operating envelope can be extended. In this paper, we quantitatively assess the performance potential and scientific feasibility of MHD-bypass engines using a simplified thermodynamic analysis. This cycle analysis, based on a thermally and calorically perfect gas, incoporates a coupled MHD generator-accelerator system and accounts for aerodynamic losses and thermodynamic process efficiencies in the various engine components. It is found that the flight Mach number range can be significantly extended; however, overall performance is hampered by non-isentropic losses in the MHD devices.