Global momentum confinement times in Alcator C-Mod H- and I- regime plasmas
Name
898190284-MIT.pdf
Description
Full printable version
Size
3.78 MB
Format
Adobe PDF
Checksum (MD5)
146bb28cce72e54d2cc1d09afc55ef59
Author(s)
Victora, Michelle (Michelle M.)
Advisor(s)
Bruno Coppi and John Rice.
Date Issued
2014
Publisher
Massachusetts Institute of Technology
Abstract
Using a spatially-resolving x-ray spectrometer system, the toroidal rotation velocity in Alcator C-Mod plasmas is measured and analyzed. At the L-H and L-I transition, there is a co-current movement in the toroidal rotation velocity.The propagation of this rotational velocity from the edge to the core of the torus was measured following the L- to H- and L- to I-mode transitions. A hyperbolic tangent fit was used to determine a single variable for rise time in rotational velocity. The hyperbolic tangent fit parameter acts as a proxy for the global momentum confinement time, which is then compared to other plasma parameters. Through this compaxison, we found an decrease in rise time in correlation with increasing density(n)/current(I), particularly distinctive in the range of 1-2.5 x 10²⁰ (MA x m³)-¹. Due to a lack of overlap in density between I- and H-mode, we find this may be indicative of an overall decrease in rise time between L- to I- and L- to H-mode transitions. In order to explore this possibility, we must achieve I-mode runs with the same current and density as Hmode to determine if there is still a decrease between the two transitions.
Description
Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 43-45).
Subjects
Physics.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
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