Effects of Boundary Conditions and Flow on the Kink Instability in a Cylindrical Plasma Column
Abstract
An experimental investigation of the kink instability is presented in a linear plasma column where one end is linetied to the plasma source, and the other end is not linetied and therefore free to slide over the surface of the endplate. This latter boundary condition is a result of plasma sheath resistance that insulates, at least partially, the plasma from the endplate. The helical m = 1 kink mode is observed to grow when the plasma current exceeds a threshold and, close to the criticality, is characterized by an axial mode structure with maximum displacement at the free axial boundary. Azimuthal rotation of the mode is observed such that the helically kinked column always screws into the free axial boundary. The kink mode structure, rotation frequency and instability threshold are accurately reproduced by a recent kink theory [D. D. Ryutov, et al., Phys. Plasmas 13, 032105 (2006)], which includes axial plasma flow and one end of the plasma column that is free to move due to a perfect nonlinetying boundary condition which is experimentally verified. A brief review of the kink theory and its predictions for the boundary conditions relevant in the present experiments are presented.
 Authors:
 Publication Date:
 Research Org.:
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 908899
 Report Number(s):
 UCRLJRNL227871
Journal ID: ISSN 1070664X; PHPAEN; TRN: US0703793
 DOE Contract Number:
 W7405ENG48
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physics of Plasmas, N/A, N/A, February 28, 2007, pp. 022103
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION; BOUNDARY CONDITIONS; CRITICALITY; INSTABILITY; KINK INSTABILITY; PLASMA; PLASMA SHEATH; ROTATION
Citation Formats
Furno, I, Intrator, T P, Lapenta, G, Dorf, L, and Ryutov, D D. Effects of Boundary Conditions and Flow on the Kink Instability in a Cylindrical Plasma Column. United States: N. p., 2007.
Web. doi:10.1063/1.2435306.
Furno, I, Intrator, T P, Lapenta, G, Dorf, L, & Ryutov, D D. Effects of Boundary Conditions and Flow on the Kink Instability in a Cylindrical Plasma Column. United States. doi:10.1063/1.2435306.
Furno, I, Intrator, T P, Lapenta, G, Dorf, L, and Ryutov, D D. Tue .
"Effects of Boundary Conditions and Flow on the Kink Instability in a Cylindrical Plasma Column". United States.
doi:10.1063/1.2435306. https://www.osti.gov/servlets/purl/908899.
@article{osti_908899,
title = {Effects of Boundary Conditions and Flow on the Kink Instability in a Cylindrical Plasma Column},
author = {Furno, I and Intrator, T P and Lapenta, G and Dorf, L and Ryutov, D D},
abstractNote = {An experimental investigation of the kink instability is presented in a linear plasma column where one end is linetied to the plasma source, and the other end is not linetied and therefore free to slide over the surface of the endplate. This latter boundary condition is a result of plasma sheath resistance that insulates, at least partially, the plasma from the endplate. The helical m = 1 kink mode is observed to grow when the plasma current exceeds a threshold and, close to the criticality, is characterized by an axial mode structure with maximum displacement at the free axial boundary. Azimuthal rotation of the mode is observed such that the helically kinked column always screws into the free axial boundary. The kink mode structure, rotation frequency and instability threshold are accurately reproduced by a recent kink theory [D. D. Ryutov, et al., Phys. Plasmas 13, 032105 (2006)], which includes axial plasma flow and one end of the plasma column that is free to move due to a perfect nonlinetying boundary condition which is experimentally verified. A brief review of the kink theory and its predictions for the boundary conditions relevant in the present experiments are presented.},
doi = {10.1063/1.2435306},
journal = {Physics of Plasmas, N/A, N/A, February 28, 2007, pp. 022103},
number = ,
volume = ,
place = {United States},
year = {Tue Feb 06 00:00:00 EST 2007},
month = {Tue Feb 06 00:00:00 EST 2007}
}

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