Forward Thomson Scattering for the Measurement of Weakly Ionized Plasmas in Hypersonic Flows
Abstract
Performer proposes research on a new concept for the measurement of electron temperature and density in weakly ionized plasmas such as those surrounding a hypersonic platform. Performer concept is based on Filtered Low Angle Thomson Scattering. It has the capability to suppress background interference from Rayleigh and Raman scattering and plasma luminosity and thus to extend significantly the low electron density limit of Thomson scattering. The measurement is based on the frequency narrowing of the Thomson scattering in the forward direction and eliminates overlap with rotational Raman lines. The measurement can be precisely located in the flow and made time accurate, depending on the single pulse signal level. A high resolution filtertogether with the use of pulsed laser illumination and synchronized time gated detection providevery strong suppression of plasma luminosity. The forward scattering nature of this proposed approach provides convenient access to existing wind tunnel, expansion tube and shock tunnel models through Schlieren type side windows. Initial experiments are proposed using a Ti:sapphire laser and a rubidium filter, and the development of megahertz approaches using a pulse burst laser is envisioned.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 29, 2020
- Source ID
- N000142012348
Entities
People
- Richard B. Miles
Organizations
- Office of Naval Research
- Texas Engineering Experiment Station
- United States Navy