Testing of coaxial railguns in high vacuum

The goal of many railgun investigations is to arrive at a railgun design that is capable of launching projectiles to extremely high velocities (10 to 100 km/s). Often a second goal is for the railgun design to allow for repetitive launches without a total rebuild of the railgun. These two goals are the objectives the Center for Electromechanics at The University of Texas at Austin (CEM-UT) has pursued over the past several years. As part of the investigation, a serious study of coaxial railguns was conducted. Coaxial railguns were studied because the coaxial geometry offers two attractive features. One feature is the simplified construction, and the other is an inherent lower L' value. Studies were conducted on 0.5-and 5.0-m long coaxial railguns. Results were mixed in that high velocities were obtained (37 km/s), and several shots were done on one gun without cleanup or rebuild, but plasma mass amounts were small and not tightly patterned. Experiments are still underway, on a limited basis, to attempt to focus and bunch the plasma during launch and as it exists the muzzle.