Accession Number : AD1021890

Title :   Comprehensive Study of Plasma-Wall Sheath Transport Phenomena

Descriptive Note : Technical Report,01 Jul 2011,30 Jun 2016

Corporate Author : Georgia Institute of Technology Atlanta

Personal Author(s) : Walker,Mitchell L ; Ready,W J ; Thompson,Greg ; Rimoli,Julian J ; Keidar,Michael

Full Text :

Report Date : 26 Oct 2016

Pagination or Media Count : 73

Abstract : In order to facilitate the development of the next generation of electric propulsion (EP) devices for USAF space assets and overcome current limitations in power density and specific mass, investigators from Georgia Institute of Technology (GT), University of Alabama (UA), and George Washington University(GWU) performed a comprehensive multidisciplinary study on the nature and transport properties of the interaction between a plasma and a confining wall material. Hysteresis effects observed in the floating potential of wall material samples immersed in a low-temperature plasma were studied. Hysteresis is found to be due to secondary electron emission from the wall material surface. The impact of surface roughness and sheath-scale surface profiles on space charge saturation of plasma sheaths was investigated. The preliminary results of models have proven that the thermal conductivity distribution largely impacts the crack nucleation and propagation process in boron nitride. The experimental investigation of the erosion of stressed materials was continued for fused silica and M26 borosil. The work shows that the evolution of theM26 surface is governed by the complex microstructure of the material.

Descriptors :   electric propulsion , TRANSPORT PROPERTIES , PLASMAS (PHYSICS) , HYSTERESIS , electron emission , surface roughness , thermal conductivity , plasma sheaths , multiscale models , materials testing , crystal structure , microstructure , graphite , THERMOMECHANICS , materials science , ceramic materials , hall thrusters , composite materials

Subject Categories : Plasma Physics and Magnetohydrodynamics
      Ceramics, Refractories and Glass
      Electric and Ion Propulsion

Distribution Statement : APPROVED FOR PUBLIC RELEASE