Accession Number : ADA130143

Title :   Potentials and Charges on Conducting Rocket Sections.

Descriptive Note : Environmental research papers,

Corporate Author : AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA

Personal Author(s) : Dubs,Charles W

PDF Url : ADA130143

Report Date : 12 Nov 1982

Pagination or Media Count : 36

Abstract : An analysis is made of the potential differences measured by Cohen et al between pairs of three rocket conductors when various ion or electron beams are emitted. Approximate values of coefficients of potential, capacity, and induction are calculated. A simple method of measuring them is also presented. Approximate formulae are developed for sheath radius and are used to calculate this radius for each of six beam currents. The extended probe is found to be inside the sheath for all of the beam currents except 1 Micro A. The potential of the rear section is shown to be close to zero, so is assumed equal to zero, which leads immediately to the absolute potentials of the rocket sections. Approximate formulae are developed to calculate the sheath potential from the charge in the sheath. A fast converging reiteration gives the charge on each conductor, the sheath charge, and the part of the conductor potentials that are due to the sheath. Explanations are given for: (1) the charge on the rear section having the opposite sign of, and a smaller magnitude than that on the forward section; (2) the magnitude of the probe voltmeter reading being less than that of the rear section voltmeter for moderate beam currents, and the same for beam currents way beyond saturation; (3) the ratio of these two voltmeter readings approaching 1 with increasing magnitude of beam current; (4) the potential of the probe being negative for ion emission; (5) the magnitude of the probe potential reaching a maximum, then approaching zero with increasing magnitude of beam current.

Descriptors :   *SPACE CHARGE, *IONOSPHERE, IONIZATION POTENTIALS, ELECTRON BEAMS, ION DENSITY, POTENTIAL FLOW, SPACECRAFT COMPONENTS, ROCKET COMPONENTS, CONDUCTIVITY

Subject Categories : Atmospheric Physics
      Electricity and Magnetism
      Rocket Engines
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE