Accession Number:

ADA456676

Title:

Millimeter Wave Plasma Interferometry in the Near Field of a Hall Plasma Accelerator (PREPRINT)

Descriptive Note:

Journal Article

Corporate Author:

STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING

Report Date:

2006-01-27

Pagination or Media Count:

25.0

Abstract:

Measurements are described of electron number density in the near field of a 200W Hall plasma accelerator using a 90 GHz microwave interferometer. The system is of a phase-bridge design, utilizing two signal arms from a fixed frequency source one passing through the plasma that recombine at two balanced mixers. A line-integrated electron density is obtained by comparing the in-phase and quadrature signals from the mixers. Measurements across chords through a symmetric plasma plume are Abel inverted to give the radial variation in the plasma density. The first direct non-intrusive measurements of the electron density in the near field of this source reveals structure not previously resolved with electrical probes. This interferometer is suitable for measuring time-dependent plasma density fluctuations offering non-intrusive information about plasma oscillations and instabilities in the near exit region where electrical probes are known to interfere with the discharge operation.

Subject Categories:

  • Test Facilities, Equipment and Methods
  • Plasma Physics and Magnetohydrodynamics
  • Electric and Ion Propulsion

Distribution Statement:

APPROVED FOR PUBLIC RELEASE