Date of Award
Master of Science
Department of Engineering Physics
James C. Petrosky, PhD.
The direct current produced from the Van de Graaff (VDG) at the Air Force Research Laboratory (AFRL) has been measured and analyzed. The current pulse produced from the VDG is oscillatory. Experimental data show complete damping occurs after 8 oscillations and within 10-6 seconds. The spark gap distance and circuit resistance were varied to determine if the circuit could convert to an overdamped RLC circuit in order to reduce the oscillations. The data establishes that the VDG produces at least 3 full wave Fourier frequencies of: 3, 7, and 15 MHz ± 2.0 MHz, while the first oscillation had a measured mean frequencies of: 8.56 MHz ± 0.4 MHz for the 3" spark gap distance; 6" had a measured frequency of 13.95 MHz ± 1.0 MHz, and finally 7" had a measured value of 15.78 MHz ±1.3 MHz. The direct current amplitude of the first oscillation also rose as a function of spark gap distance from 202 ± 13.82 (A) at a spark gap of 3" to 354 ± 22.10 (A) for a spark gap of 8". Using the settings explored in this thesis, the VDG has some value for use in preliminary Electromagnetic (EMP) direct current testing, but further research is required in order for it to meet MIL-STD-464 validation criteria.
DTIC Accession Number
Kress, Robert J., "Analysis of a Van De Graaff Generator for EMP Direct Current Survivability Testing" (2013). Theses and Dissertations. 935.