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Title: Measurements of the toroidal torque balance of error field penetration locked modes

Abstract

Here, detailed measurements from the DIII-D tokamak of the toroidal dynamics of error field penetration locked modes under the influence of slowly evolving external fields, enable study of the toroidal torques on the mode, including interaction with the intrinsic error field. The error field in these low density Ohmic discharges is well known based on the mode penetration threshold, allowing resonant and non-resonant torque effects to be distinguished. These m/n = 2/1 locked modes are found to be well described by a toroidal torque balance between the resonant interaction with n = 1 error fields, and a viscous torque in the electron diamagnetic drift direction which is observed to scale as the square of the perturbed field due to the island. Fitting to this empirical torque balance allows a time-resolved measurement of the intrinsic error field of the device, providing evidence for a time-dependent error field in DIII-D due to ramping of the Ohmic coil current.

Authors:
 [1];  [2];  [1];  [3];  [4];  [1];  [3];  [1];  [1]
  1. Columbia Univ., New York, NY (United States)
  2. Oak Ridge Institute for Science and Education, Oak Ridge, TN (United States)
  3. General Atomics, San Diego, CA (United States)
  4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1367534
Grant/Contract Number:  
FC02-04ER54698; SC0008520; AC05-06OR23100; AC02-09CH11466
Resource Type:
Accepted Manuscript
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Volume: 57; Journal Issue: 2; Journal ID: ISSN 0741-3335
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tokamak; locked mode; error field; torque balance

Citation Formats

Shiraki, Daisuke, Paz-Soldan, Carlos, Hanson, Jeremy M., La Haye, Robert J., Logan, Nikolas C., Olofsson, K. E. J., Strait, Edward J., Sweeney, Ryan M., and Volpe, Francesco A. Measurements of the toroidal torque balance of error field penetration locked modes. United States: N. p., 2015. Web. doi:10.1088/0741-3335/57/2/025016.
Shiraki, Daisuke, Paz-Soldan, Carlos, Hanson, Jeremy M., La Haye, Robert J., Logan, Nikolas C., Olofsson, K. E. J., Strait, Edward J., Sweeney, Ryan M., & Volpe, Francesco A. Measurements of the toroidal torque balance of error field penetration locked modes. United States. doi:10.1088/0741-3335/57/2/025016.
Shiraki, Daisuke, Paz-Soldan, Carlos, Hanson, Jeremy M., La Haye, Robert J., Logan, Nikolas C., Olofsson, K. E. J., Strait, Edward J., Sweeney, Ryan M., and Volpe, Francesco A. Mon . "Measurements of the toroidal torque balance of error field penetration locked modes". United States. doi:10.1088/0741-3335/57/2/025016. https://www.osti.gov/servlets/purl/1367534.
@article{osti_1367534,
title = {Measurements of the toroidal torque balance of error field penetration locked modes},
author = {Shiraki, Daisuke and Paz-Soldan, Carlos and Hanson, Jeremy M. and La Haye, Robert J. and Logan, Nikolas C. and Olofsson, K. E. J. and Strait, Edward J. and Sweeney, Ryan M. and Volpe, Francesco A.},
abstractNote = {Here, detailed measurements from the DIII-D tokamak of the toroidal dynamics of error field penetration locked modes under the influence of slowly evolving external fields, enable study of the toroidal torques on the mode, including interaction with the intrinsic error field. The error field in these low density Ohmic discharges is well known based on the mode penetration threshold, allowing resonant and non-resonant torque effects to be distinguished. These m/n = 2/1 locked modes are found to be well described by a toroidal torque balance between the resonant interaction with n = 1 error fields, and a viscous torque in the electron diamagnetic drift direction which is observed to scale as the square of the perturbed field due to the island. Fitting to this empirical torque balance allows a time-resolved measurement of the intrinsic error field of the device, providing evidence for a time-dependent error field in DIII-D due to ramping of the Ohmic coil current.},
doi = {10.1088/0741-3335/57/2/025016},
journal = {Plasma Physics and Controlled Fusion},
number = 2,
volume = 57,
place = {United States},
year = {2015},
month = {1}
}

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