Evolution of edge pedestal transport between ELMs in DIII-D

Floyd, John-Patrick

Title:

Evolution of edge pedestal transport between ELMs in DIII-D

dc.contributor.advisor	Stacey, Weston M.
dc.contributor.author	Floyd, John-Patrick
dc.contributor.committeeMember	Erickson, Anna
dc.contributor.committeeMember	Groebner, Richard J.
dc.contributor.committeeMember	McGrath, Robert T.
dc.contributor.committeeMember	Utschig, Tristan T.
dc.contributor.department	Mechanical Engineering
dc.date.accessioned	2015-01-12T20:52:39Z
dc.date.available	2015-01-12T20:52:39Z
dc.date.created	2014-12
dc.date.issued	2014-11-14
dc.date.submitted	December 2014
dc.date.updated	2015-01-12T20:52:39Z
dc.description.abstract	Evolution of measured profiles of densities, temperatures and velocities in the edge pedestal region between successive ELM (edge-localized mode) events are analyzed and interpreted in terms of the constraints imposed by particle, momentum and energy balance in order to gain insights regarding the underlying evolution of transport processes in the edge pedestal between ELMs in a series of DIII-D discharges. The data from successive inter-ELM periods during an otherwise steady-state phase of the discharges were combined into a composite inter-ELM period for the purpose of increasing the number of data points in the analysis. These composite periods were partitioned into sequential intervals to examine inter-ELM transport evolution. The GTEDGE integrated modeling code was used to calculate and interpret plasma transport and properties during each interval using particle, momentum, and energy balance. Variation of diffusive and non-diffusive (pinch) particle, momentum, and energy transport over the inter-ELM period are examined for discharges with plasma currents from 0.5 to 1.5 MA and inter-ELM periods from 50 to 220 ms. Diffusive transport is dominant for ρ< 0.925, while non-diffusive and diffusive transport are very large and nearly balancing in the sharp gradient region 0.925 <ρ <1.0. Transport effects of ion orbit loss are significant for ρ > 0.95, and are taken into account. During the inter-ELM period, diffusive transport increases slightly more than non-diffusive transport, increasing total outward transport. Both diffusive and non-diffusive transport have a strong inverse correlation with plasma current. Weakening the electromagnetic pinch may increase outward particle transport, and enable control over the rebuilding of the edge pedestal between ELMs.
dc.description.degree	Ph.D.
dc.format.mimetype	application/pdf
dc.identifier.uri	http://hdl.handle.net/1853/53079
dc.language.iso	en_US
dc.publisher	Georgia Institute of Technology
dc.subject	DIII-D
dc.subject	ELMs
dc.subject	Plasma
dc.subject	Fusion
dc.subject	Plasma physics
dc.subject	Magnetic confinement
dc.subject	Pinch-diffusion
dc.subject	Pedestal
dc.subject	Edge pedestal
dc.subject	Transport
dc.subject	Pinch
dc.title	Evolution of edge pedestal transport between ELMs in DIII-D
dc.type	Text
dc.type	Dataset
dc.type.genre	Dissertation
dspace.entity.type	Publication
local.contributor.advisor	Stacey, Weston M.
local.contributor.corporatename	George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename	College of Engineering
relation.isAdvisorOfPublication	c0f53c49-e84d-46a7-b831-23770e787081
relation.isOrgUnitOfPublication	c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication	7c022d60-21d5-497c-b552-95e489a06569
thesis.degree.level	Doctoral