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The Naval Research Laboratory (NRL) performs basic and applied research on high power railguns as part of the US Navy EM Launcher program. The understanding of damage mechanisms as a function of armature and barrel materials, launch parameters, and bore geometry is of primary interest to the development of a viable high power railgun. Research is performed on a 6m, 1.5 MJ railgun located at NRL. Barrel studies utilize in situ diagnostics coupled with detailed ex situ analysis of rail materials to provide clues to the conditions present during launch. Results are compared with coupled 3-D electromagnetic and mechanical Finite Element Analysis (FEA) models of railgun operation. Results of several experiments on rail wear will be discussed.

The Naval Research Laboratory performs basic research on high power railgun electric launchers. The program uses a 1.5-MJ, 2.5 km/s launch velocity railgun located in NRL's Materials Testing Facility. The railgun consists of an 11-MJ capacitive energy store configured as 22, 0.5-MJ modules. Each bank module has an independently triggered thyristor switch, series inductor, and crowbar diode and is joined to the railgun breech with coaxial cables. Individual bank timing and charge levels can be set to produce up to 1.5 MA peak current and 4-5 ms long current pulses. The 6-m long railgun used a nominally 5 cm bore diameter with steel or copper rails and epoxy laminate insulators. The muzzle contains a Tungsten-Copper arc horn to minimize damage from residual drive current upon launch. Aluminum armatures with acrylic bore riders are used for the launch package. Launch data is recorded digitally and analyzed using in-house computer codes. The system design and operation will be discussed.

The Naval Research Laboratory performs basic research on high power railgun electric launchers. The program uses a 1.5-MJ, 2.5 km/s launch velocity railgun located in NRL's Materials Testing Facility. The railgun consists of an 11-MJ capacitive energy store configured as 22, 0.5-MJ modules. Each bank module has an independently triggered thyristor switch, series inductor, and crowbar diode and is joined to the railgun breech with coaxial cables. Individual bank timing and charge levels can be set to produce up to 1.5 MA peak current and 4-5 ms long current pulses. The 6-m long railgun used a nominally 5 cm bore diameter with steel or copper rails and epoxy laminate insulators. The muzzle contains a Tungsten-Copper arc horn to minimize damage from residual drive current upon launch. Aluminum armatures with acrylic bore riders are used for the launch package. Launch data is recorded digitally and analyzed using in-house computer codes. The system design and operation will be discussed.

The Material Test Facility (MTF) houses a medium-caliber electromagnetic (EM) railgun that is designed for ease of access. As such, it is ideal for developing diagnostics for measuring the performance of EM launchers. Multiple in situ diagnostics have been fielded on the MTF railgun including field sensors for position location and thermal sensors. Kinematics of the launch package are of particular interest. B-dot loops are the usual method, but many such B-dots are required to obtain a detailed evolution of position and velocity. This requires many channels and consumes data acquisition resources. Naval Research Lab (NRL) has developed several versions of a flux ladder diagnostic, which include many pick-up loops on one data channel. Some versions have multiple flux ladders interleaved to maintain pulse separation in a single channel, but which increase the overall spatial resolution. A typical MTF configuration has 58 positions monitored in just three channels. Careful processing has yielded velocity and even acceleration. NRL is also developing a flux loop diagnostic that has the potential for continuous kinematics with the time resolution of the digital sampling rate. However, flux loops are more sensitive to spurious signal sources. Preliminary flux loop results are presented.