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Title: Analytical formula for pellet fuel source density in toroidal plasma configurations based on an areal deposition model

Abstract

An analytical formula for the fuel source density ηF (Ψ) over a magnetic flux surface Ψ following pellet injection is derived. During pellet motion the ablated and ionized fuel will be initially deposited nearby the pellet, prior to subsequent homogenization within the magnetic flux surfaces. Here in our research, it is assumed that the deposition area projected normal to the magnetic field is on the order of the cross-sectional area of the ionized ablation column whose axis is aligned with the magnetic field. Previous pellet deposition codes [1] employed a point source deposition approximation, which overpredicts the surface-averaged density, particularly when the obliquity between the pellet trajectory and the flux surface normal approaches 90 degrees. A key finding of this study is that as the obliquity approaches 90 degrees, grazing trajectory, the areal model predicts a well behaved ηF and removes the unphysical divergence stemming from the point model. To illustrate the difference exhibited between areal and point models for near grazing trajectories, we considered vertical pellet injection into a CFETR-like tokamak with a negative triangularity plasma cross section using a pellet ablation/deposition module.

Authors:
 [1];  [2]
  1. Univ. of Science and Technology of China, Hefei (China)
  2. General Atomics, San Diego, CA (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); National Key R&D Program of China; National Natural Science Foundation of China (NNSFC)
OSTI Identifier:
1630434
Grant/Contract Number:  
FG02-95ER54309; 2017YFE0300400
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 60; Journal Issue: 6; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; fuel source density; pellet ablation; pellet deposition

Citation Formats

Zhang, Jie, and Parks, Paul. Analytical formula for pellet fuel source density in toroidal plasma configurations based on an areal deposition model. United States: N. p., 2020. Web. doi:10.1088/1741-4326/ab868e.
Zhang, Jie, & Parks, Paul. Analytical formula for pellet fuel source density in toroidal plasma configurations based on an areal deposition model. United States. doi:https://doi.org/10.1088/1741-4326/ab868e
Zhang, Jie, and Parks, Paul. Fri . "Analytical formula for pellet fuel source density in toroidal plasma configurations based on an areal deposition model". United States. doi:https://doi.org/10.1088/1741-4326/ab868e.
@article{osti_1630434,
title = {Analytical formula for pellet fuel source density in toroidal plasma configurations based on an areal deposition model},
author = {Zhang, Jie and Parks, Paul},
abstractNote = {An analytical formula for the fuel source density ηF (Ψ) over a magnetic flux surface Ψ following pellet injection is derived. During pellet motion the ablated and ionized fuel will be initially deposited nearby the pellet, prior to subsequent homogenization within the magnetic flux surfaces. Here in our research, it is assumed that the deposition area projected normal to the magnetic field is on the order of the cross-sectional area of the ionized ablation column whose axis is aligned with the magnetic field. Previous pellet deposition codes [1] employed a point source deposition approximation, which overpredicts the surface-averaged density, particularly when the obliquity between the pellet trajectory and the flux surface normal approaches 90 degrees. A key finding of this study is that as the obliquity approaches 90 degrees, grazing trajectory, the areal model predicts a well behaved ηF and removes the unphysical divergence stemming from the point model. To illustrate the difference exhibited between areal and point models for near grazing trajectories, we considered vertical pellet injection into a CFETR-like tokamak with a negative triangularity plasma cross section using a pellet ablation/deposition module.},
doi = {10.1088/1741-4326/ab868e},
journal = {Nuclear Fusion},
number = 6,
volume = 60,
place = {United States},
year = {2020},
month = {5}
}

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