Accession Number:

ADA158447

Title:

Microwave Interaction with Air

Descriptive Note:

Corporate Author:

MISSION RESEARCH CORP ALEXANDRIA VA

Personal Author(s):

Report Date:

1985-06-01

Pagination or Media Count:

46.0

Abstract:

Microwave breakdown studies of gaseous elements have been carried out extensively over a wide range of pressures and for several microwave frequencies using CW and pulsed radiation sources. The main emphasis in these studies was on the determination of the breakdown power threshold and its dependence on the gas pressure and the microwave frequency. The coupling of mircowave energy into the breakdown plasma and neutral gas has not been studied in detail. The reason for this is that, until recently, no high-power microwave sources have been available to perform such studies. Most of the early work performed on breakdown thresholds was performed using high Q cavities to obtain the necessary electric field to break down the gas. Once breakdown of the gas occurred, the Q of the cavity dropped and the interaction changed. Using the NRL high-power gyrtron facility, we have been able to eliminate the need for cavities and have performed experiments using a focused geometry to examine the coupling of microwave energy to nitrogen gas during breakdown. We have also modeled the experiments using a 1-D computer simulation code. Simulations were performed in a spherical geometry using a self-consistent, nitrogen chemistry, wave optics, microwave breakdown simulation code, MINI. The main emphasis of past work was on the ionization front created during nitrogen breakdown and its motion and plasma properties, as observed experimentally.

Subject Categories:

  • Atmospheric Physics
  • Electrical and Electronic Equipment
  • Plasma Physics and Magnetohydrodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE