Electromagnetic projectile acceleration utilizing distributed energy sources

Journal Article · Fri Oct 01 00:00:00 EDT 1982 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.330056· OSTI ID:6729321

Parker, J V

Circuit equations are derived for an electromagnetic projectile accelerator (railgun) powered by a large number of capacitive discharge circuits distributed along its length. The circuit equations are put into dimensionless form and the parameters governing the solutions derived. After specializing the equations to constant spacing between circuits, the case of lossless rails and negligible drag is analyzed to show that the electrical to kinetic energy transfer efficiency is equal to sigma/2, where sigma = 2mS/Lq/sup 2//sub 0/ and m is the projectile mass, S the distance between discharge circuit, Lthe rail inductance per unit length, and q/sub 0/ the charge on the first stage capacitor. For sigma = 2 complete transfer of electrical to kinetic energy is predicted while for sigma>2 the projective-discharge circuit system is unstable. Numerical solutions are presented for both lossless rails and for finite rail resistance. When rail resistance is included, >70% transfer is calculated for accelerators of arbitrary length. The problem of projectile startup is considered and a simple modification of the first two stages is described which provides proper startup. Finally, the results of the numerical solutions are applied to a practical railgun design. A research railgun designed for repeated operation at 50 km/sec is described. It would have an overall length of 77 m, an electrical efficiency of 81%, a stored energy per stage of 105 kJ, and a charge transfer of <50 C per stage. A railgun of this design appears to be practicable with current pulsed power technology.

• Research Organization: Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6729321
• Journal Information: J. Appl. Phys.; (United States), Vol. 53:10
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
RAILGUN ACCELERATORS
MATHEMATICAL MODELS
PROJECTILES
ACCELERATION
CAPACITORS
DESIGN
EFFICIENCY
ELECTRIC DISCHARGES
ELECTROMAGNETIC FIELDS
ELECTRONIC CIRCUITS
INSTABILITY
KINETIC ENERGY
LENGTH
PARAMETRIC ANALYSIS
ACCELERATORS
DIMENSIONS
ELECTRICAL EQUIPMENT
ENERGY
EQUIPMENT
420800* - Engineering- Electronic Circuits &amp; Devices- (-1989)