Date of Award

3-21-2013

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

James C. Petrosky, PhD.

Abstract

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.

AFIT Designator

AFIT-ENP-13-M-39

DTIC Accession Number

ADA574271

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