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Title: Blobs and drift wave dynamics

Abstract

The modified Hasegawa-Mima equation retaining all nonlinearities is investigated from the point of view of the formation of blobs. The linear analysis shows that the amplitude of the drift wave packet propagating in the direction of decreasing background plasma density increases and eventually saturates due to nonlinear effects. Nonlinear modification of the time averaged plasma density profile results in the formation of large amplitude modes locked in the radial direction, but still propagating in the poloidal direction, which resembles the experimentally observed chain of blobs propagating in the poloidal direction. Such specific density profiles, causing the locking of drift waves, could form naturally at the edge of tokamak due to a neutral ionization source. Thus, locked modes can grow in situ due to plasma instabilities, e.g., caused by finite resistivity. Furthermore, the modulation instability (in the poloidal direction) of these locked modes can result in a blob-like burst of plasma density.

Authors:
ORCiD logo [1];  [1]
  1. Univ. of California, San Diego, CA (United States). Mechanical and Aerospace Engineering Dept.
Publication Date:
Research Org.:
Univ. of California, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1395535
Alternate Identifier(s):
OSTI ID: 1395589
Grant/Contract Number:  
FG02-04ER54739
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 9; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; blobs; drift wave

Citation Formats

Zhang, Yanzeng, and Krasheninnikov, S. I. Blobs and drift wave dynamics. United States: N. p., 2017. Web. doi:10.1063/1.4994833.
Zhang, Yanzeng, & Krasheninnikov, S. I. Blobs and drift wave dynamics. United States. doi:10.1063/1.4994833.
Zhang, Yanzeng, and Krasheninnikov, S. I. Fri . "Blobs and drift wave dynamics". United States. doi:10.1063/1.4994833. https://www.osti.gov/servlets/purl/1395535.
@article{osti_1395535,
title = {Blobs and drift wave dynamics},
author = {Zhang, Yanzeng and Krasheninnikov, S. I.},
abstractNote = {The modified Hasegawa-Mima equation retaining all nonlinearities is investigated from the point of view of the formation of blobs. The linear analysis shows that the amplitude of the drift wave packet propagating in the direction of decreasing background plasma density increases and eventually saturates due to nonlinear effects. Nonlinear modification of the time averaged plasma density profile results in the formation of large amplitude modes locked in the radial direction, but still propagating in the poloidal direction, which resembles the experimentally observed chain of blobs propagating in the poloidal direction. Such specific density profiles, causing the locking of drift waves, could form naturally at the edge of tokamak due to a neutral ionization source. Thus, locked modes can grow in situ due to plasma instabilities, e.g., caused by finite resistivity. Furthermore, the modulation instability (in the poloidal direction) of these locked modes can result in a blob-like burst of plasma density.},
doi = {10.1063/1.4994833},
journal = {Physics of Plasmas},
number = 9,
volume = 24,
place = {United States},
year = {Fri Sep 29 00:00:00 EDT 2017},
month = {Fri Sep 29 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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