Raman Spectroscopy of Carbon Dust Samples from NSTX
Abstract
The Raman spectrum of dust particles exposed to the NSTX plasma is different from the spectrum of unexposed particles scraped from an unused graphite tile. For the unexposed particles, the high energy G-mode peak (Raman shift ~1580 cm-1) is much stronger than the defect-induced D-mode peak (Raman shift ~ 1350 cm-1), a pattern that is consistent with Raman spectrum for commercial graphite materials. For dust particles exposed to the plasma, the ratio of G-mode to D-mode peaks is lower and becomes even less than 1. The Raman measurements indicate that the production of carbon dust particles in NSTX involves modifications of the physical and chemical structure of the original graphite material. These modifications are shown to be similar to those measured for carbon deposits from atmospheric pressure helium arc discharge with an ablating anode electrode made from a graphite tile material. We also demonstrate experimentally that heating to 2000-2700 K alone can not explain the observed structural modifications indicating that they must be due to higher temperatures needed for graphite vaporization, which is followed either by condensation or some plasma-induced processes leading to the formation of more disordered forms of carbon material than the original graphite.
- Authors:
- Publication Date:
- Research Org.:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 960229
- Report Number(s):
- PPPL-4293
TRN: US0904586
- DOE Contract Number:
- DE-ACO2-76CHO3073
- Resource Type:
- Conference
- Resource Relation:
- Journal Issue: 8; Conference: Dust in Fusion Plasmas" July 8-10, 2007 (Satellite Meeting of the 34th European Physical Society Conf. on Plasma Physics).
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANODES; ATMOSPHERIC PRESSURE; CARBON; DUSTS; ELECTRODES; EVAPORATION; GRAPHITE; HEATING; HELIUM; MODIFICATIONS; PHYSICS; PLASMA; PRODUCTION; RAMAN SPECTROSCOPY; NSTX
Citation Formats
Y. Raitses, C.H. Skinner, F. Jiang and T.S. Duffy. Raman Spectroscopy of Carbon Dust Samples from NSTX. United States: N. p., 2008.
Web.
Y. Raitses, C.H. Skinner, F. Jiang and T.S. Duffy. Raman Spectroscopy of Carbon Dust Samples from NSTX. United States.
Y. Raitses, C.H. Skinner, F. Jiang and T.S. Duffy. 2008.
"Raman Spectroscopy of Carbon Dust Samples from NSTX". United States. https://www.osti.gov/servlets/purl/960229.
@article{osti_960229,
title = {Raman Spectroscopy of Carbon Dust Samples from NSTX},
author = {Y. Raitses, C.H. Skinner, F. Jiang and T.S. Duffy},
abstractNote = {The Raman spectrum of dust particles exposed to the NSTX plasma is different from the spectrum of unexposed particles scraped from an unused graphite tile. For the unexposed particles, the high energy G-mode peak (Raman shift ~1580 cm-1) is much stronger than the defect-induced D-mode peak (Raman shift ~ 1350 cm-1), a pattern that is consistent with Raman spectrum for commercial graphite materials. For dust particles exposed to the plasma, the ratio of G-mode to D-mode peaks is lower and becomes even less than 1. The Raman measurements indicate that the production of carbon dust particles in NSTX involves modifications of the physical and chemical structure of the original graphite material. These modifications are shown to be similar to those measured for carbon deposits from atmospheric pressure helium arc discharge with an ablating anode electrode made from a graphite tile material. We also demonstrate experimentally that heating to 2000-2700 K alone can not explain the observed structural modifications indicating that they must be due to higher temperatures needed for graphite vaporization, which is followed either by condensation or some plasma-induced processes leading to the formation of more disordered forms of carbon material than the original graphite.},
doi = {},
url = {https://www.osti.gov/biblio/960229},
journal = {},
number = 8,
volume = ,
place = {United States},
year = {Thu Feb 21 00:00:00 EST 2008},
month = {Thu Feb 21 00:00:00 EST 2008}
}