Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Multi-species impurity granule injection and mass deposition projections in NSTX-U discharges

Journal Article · · Nuclear Fusion
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
+ Show Author Affiliations

Here, by employing a neutral gas shielding (NGS) model to characterize impurity granule injection, the ablation rates for three different species of granule: lithium, boron, and carbon, are determined. Utilizing the duration of ablation events recorded on experiments performed at DIII-D to calibrate the NGS model, we quantify the ablation rate with respect to the plasma density profile. The species-specific granule shielding constant is then used to model granule ablation within NSTX-U discharges. Simulations of 300, 500 and 700 micron diameter granules injected at 50 m s–1 are presented for NSTX-U L-mode type plasmas, as well as H-mode discharges with low natural ELM frequency. Additionally, ablation calculations of 500 micron granules of each species are presented at velocities ranging from 50–150 m s–1. In H-mode discharges these simulations show that the majority of the injected granule is ablated within or just past the edge steep gradient region. At this radial position, the perturbation to the background plasma generated by the ablating granule can lead to conditions advantageous for the rapid triggering of ELM crashes.

Research Organization:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC02-09CH11466
OSTI ID:
1362046
Alternate ID(s):
OSTI ID: 22925773
Journal Information:
Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 7 Vol. 57; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English

References (26)

Fueling efficiency of pellet injection on DIII-D journal March 1999
A simple apparatus for the injection of lithium aerosol into the scrape-off layer of fusion research devices journal November 2010
Techniques for injection of pre-characterized dust into the scrape-off layer of fusion plasma journal October 2011
Lithium granule ablation and penetration during ELM pacing experiments at DIII-D journal November 2016
ELM mitigation techniques journal July 2013
ELM induced tungsten melting and its impact on tokamak operation journal August 2015
ELM mitigation with pellet ELM triggering and implications for PFCs and plasma performance in ITER journal August 2015
Lithium pellet deposition and penetration in TFTR journal October 1992
Fullerene-related structure of commercial glassy carbons journal October 2004
Analysis of low Z a impurity pellet ablation for fusion diagnostic studies journal March 1988
Neutral and plasma shielding model for pellet ablation journal April 1988
Model of ablation flow near light-atom pellets with surface boundary conditions journal March 1994
High β plasmoid formation, drift and striations during pellet ablation in ASDEX Upgrade journal March 2002
Observation of ablation and acceleration of impurity pellets in the presence of energetic ions in the CHS heliotron/torsatron journal July 2002
Divertor tungsten tile melting and its effect on core plasma performance journal October 2012
First observations of ELM triggering by injected lithium granules in EAST journal September 2013
Core transport of lithium and carbon in ELM-free discharges with lithium wall conditioning in NSTX journal July 2013
Non-linear MHD modelling of ELM triggering by pellet injection in DIII-D and implications for ITER journal April 2014
Long-pulse stability limits of the ITER baseline scenario journal January 2015
High frequency pacing of edge localized modes by injection of lithium granules in DIII-D H-mode discharges journal April 2016
Theory of pellet cloud oscillation striations journal April 1996
On the fluctuation of line radiation emitted during aluminum micro-pellet ablation in magnetized plasmas journal January 1999
Review: Pellet injection experiments and modelling journal July 2007
First Observation of Edge Localized Modes Mitigation with Resonant and Nonresonant Magnetic Perturbations in ASDEX Upgrade journal June 2011
Reduction of Edge-Localized Mode Intensity Using High-Repetition-Rate Pellet Injection in Tokamak H -Mode Plasmas journal June 2013
Boron Carbide: Structure, Properties, and Stability under Stress journal October 2011

Cited By (3)

Modeling of Ablatant Deposition from Electromagnetically Driven Radiative Pellets for Disruption Mitigation Studies journal July 2019
Carbon impurities behavior and its impact on ion thermal confinement in high-ion-temperature deuterium discharges on the Large Helical Device journal May 2018
Fusion applications for lithium: wall conditioning in magnetic confinement devices journal October 2019

Similar Records

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ELM pacing
granule injection
neutral gas shielding