Scaling study for the performance of railgun armatures

Thornhill, L.D.; Batteh, Jad H.; Littrell, Donald

doi:10.1109/27.32249

Cited by 16 publications

(3 citation statements)

References 7 publications

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“…Then the relationship of velocity v end , mass m and voltage U C can be given as m-U C -v end . Similarly, since launch time t 2end has been calculated, we can obtain η corresponding to the m and U C with arbitrary value, according to equation (13). Then the relationship of efficiency η, mass m and voltage U C can be given as m-U C -η.…”

Section: Formula Derivation Of the System Efficiency Of The Syncmentioning

confidence: 99%

“…Assuming m represents the armature mass，L ' represents the rail inductance gradient, according to the principle of dynamics, the force in the armature can be described as equation (6) and the armature acceleration a can be obtained as equation (7) [12][13][14].…”

Section: Formula Derivation Of the System Efficiency Of The Syncmentioning

confidence: 99%

“…The system efficiency of the synchronously-triggered CPPS in the electromagnetic railgun system can be described as equation (13 (2 ) …”

Section: Formula Derivation Of the System Efficiency Of The Syncmentioning

confidence: 99%

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Study on the system efficiency of the synchronously-triggered capacitive pulsed-power supply in the electromagnetic railgun system

Gong

Liu

2014

2014 17th International Symposium on Electromagnetic Launch Technology

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The electromagnetic railgun system based on capacitive pulsed-power supply (CPPS) has obtained widespread applications because of its obvious advantages over the inductive ones on mature technology, operational reliability and feasible financial condition. However, the existing CPPS-based electromagnetic railgun system works with low efficiency. In this paper, the systematical study on the system efficiency of the synchronously-triggered capacitive pulsed-power supply in a 1MJ electromagnetic railgun system is proposed. Firstly, all PFUs are supposed to be triggered synchronously and the load is simplified as a resistor. Then the system performance criteria, i.e. the launch velocity of the armature v end and the system efficiency η, are expressed as the function of four independent system variables, i.e. the capacitance of each pulse forming unit (PFU) C, the pre-charged voltage U C of capacitors, the rail length l, and the armature mass m. The relationship between η (or v end ) and any two independent variables can be found under the environment of Matlab®R2012a by fixing the other two parameters. The results are then verified under the environment of Simplorer®8. These figures can be used to in instruct the design of the pulsedpower supply for a designated load or the railgun for a designated source. The study can provide a theoretical foundation for the future designs to get higher system efficiency.

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Section: Formula Derivation Of the System Efficiency Of The Syncmentioning

confidence: 99%

Section: Formula Derivation Of the System Efficiency Of The Syncmentioning

confidence: 99%

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Study on the system efficiency of the synchronously-triggered capacitive pulsed-power supply in the electromagnetic railgun system

Gong

Liu

2014

2014 17th International Symposium on Electromagnetic Launch Technology

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Probe characterization of high-current driven metal plasma in a vacuum-arc rail gun

Vijayan

Roychowdhury

Venkatramani

2004

Journal of Applied Physics

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The characteristics of metal plasma launched by high-current electric arc in a vacuum-arc rail gun are determined by employing electrical and magnetic probes. These measurements are validated by results from theoretical simulations. The arc coupled nonlinear circuit equations are solved simultaneously with the Newtonian arc motion and revealed the undercritically damped behavior of the arc current identical to the arc-current signal recorded by the Rogowski magnetic probe. Similarly the arc velocity and displacement derived from the signatures of B-dot probes are shown to concur closely with the results of J×B propulsion from simulation. The heating of plasma is formulated in a three-electron population regime with direct arc energy coupling through magnetohydrodynamic, ion-acoustic, Coulomb, and neutral interactions. This results in high temperature (Te) of hundreds of eV in the arc as revealed by the simulation. Hence Te of the rapidly cooling and equilibrating plasma that emerged from the muzzle is high around 80–90eV, which is confirmed by Langmuir electric probe measurements. Density ne of this metal plasma is shown to be in the range 4×1021–6×1021m−3 and includes multiple ion charge states. The exit velocity of the plasma measured by a pair of Langmuir probes is close to 2.2×106cm∕s and matched well with the arc velocity determined by the B-dot probes and the results from simulation.

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Spatial and temporal characteristics of a vacuum-arc rail-gun plasma

Roychowdhury¹,

Vijayan²,

Iyengar³

1997

Journal of Applied Physics

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The dynamics of a vacuum-arc operated rail-gun plasma were numerically simulated for the undercritically damped regime and confirmed in experiments. Analytical solutions of arc current, its velocity, and position also showed good agreement with the results. The spatial development of the arc is shown here to follow a linear behavior, even though the propulsion velocity followed an exponential-step function due to the sinusoidal nature of the arc current. Peak arc current ∼100 kA, 15 μs period was propelled to ∼106 cm/s as indicated in time-of-flight measurements and simulations. The voltage signal induced on a B-dot probe by the dynamic sinusoidal arc was simulated, which compared well with the measured probe signal. A Gaussian current distribution inside the measured arc length ∼1–2 cm, was established by unfolding the B-dot probe signal. A peak magnetic field of the order 1–5 kG was also interpreted inside the arc. The emerging plasma contained ion current over tens of amperes in the pulse duration encompassing the arc envelope.

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Scaling study for the performance of railgun armatures

Cited by 16 publications

References 7 publications

Study on the system efficiency of the synchronously-triggered capacitive pulsed-power supply in the electromagnetic railgun system

Study on the system efficiency of the synchronously-triggered capacitive pulsed-power supply in the electromagnetic railgun system

Probe characterization of high-current driven metal plasma in a vacuum-arc rail gun

Spatial and temporal characteristics of a vacuum-arc rail-gun plasma

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