Accession Number:

ADA429630

Title:

Investigation of Microwave Attenuation in Plasma

Descriptive Note:

Final rept. Jan 2002-Dec 2004

Corporate Author:

WRIGHT STATE UNIV DAYTON OH DEPT OF MECHANICAL AND MATERIALS ENGINEERING

Personal Author(s):

Report Date:

2005-01-04

Pagination or Media Count:

27.0

Abstract:

The computational simulation of plasma diagnostics using microwave has been successfully accomplished by the research grant. This simulation capability is based on numerical solutions to a combination of three-dimensional Maxwell equations and the generalized Ohms law in the time domain. The transverse electromagnetic wave of the TE1,0 mode transmitting from an aperture antenna, propagating through plasma, and receiving by the aperture antenna is simulated by solving these governing equations. The numerical result is first validated by comparing with classic theoretical results in waveguide then systematically applies to key components of microwave attenuation measuring arrangement. In this process, the radiation pattern of microwave from a pyramidal horn antenna, the diffraction and refraction of waves at the media interface, as well as, the blackout phenomenon of microwave propagating in a weakly ionized gas are delineated. Numerical results were obtained for a range of plasma transport properties including electrical conductivity, permittivity, and plasma frequency. The newly developed computational simulation technique has been applied to resolve the large data scattering concerns between Langmuir probes and microwave absorption measurements in the AFRLVA Mach 5 plasma channel. It was found that the irregular and fluctuating plasma generated in the magneto-hydrodynamics hypersonic facility is the main source of the measuring discrepancy. Meanwhile the simulated results contribute to a series of successful applications of hypersonic flow control via surface plasma. This achievement is also included as a revolutionary technology program by aerospace industry.

Subject Categories:

  • Computer Programming and Software
  • Plasma Physics and Magnetohydrodynamics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE