Finite Pressure Effects on the Tokamak Sawtooth Crash
Author : Yasutaro Nishimura
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Page : 292 pages
File Size : 35,20 MB
Release : 1998
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Author : Yasutaro Nishimura
Publisher :
Page : 292 pages
File Size : 35,20 MB
Release : 1998
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Author :
Publisher :
Page : 141 pages
File Size : 46,32 MB
Release : 1998
Category :
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The sawtooth crash is a hazardous, disruptive phenomenon that is observed in tokamaks whenever the safety factor at the magnetic axis is below unity. Recently, Tokamak Test Fusion Reactor (TFTR) experimental data has revealed interesting features of the dynamical pressure evolution during the crash phase. Motivated by the experimental results, this dissertation focuses on theoretical modeling of the finite pressure effects on the nonlinear stage of the sawtooth crash. The crash phase has been studied numerically employed a toroidal magnetohydrodynamic (MHD) initial value code deduced from the FAR code. For the first time, by starting from a concentric equilibrium, it has been shown that the evolution through an m/n = 1/1 magnetic island induces secondary high-n ballooning instabilities. The magnetic island evolution gives rise to convection of the pressure inside the inversion radius and builds up a steep pressure gradient across the island separatrix, or current sheet, and thereby triggers ballooning instabilities below the threshold for the axisymmetric equilibrium. Due to the onset of secondary ballooning modes, concomitant fine scale vortices and magnetic stochasticity are generated. These effects produce strong flows across the current sheet, and thereby significant modify the m = 1 driven magnetic reconnection process. The resultant interaction of the high-n ballooning modes with the magnetic reconnection process is discussed.
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Page : 336 pages
File Size : 18,99 MB
Release : 1989
Category : Plasma (Ionized gases)
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Author :
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Page : 892 pages
File Size : 27,5 MB
Release : 1999
Category : Dissertations, Academic
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Page : 782 pages
File Size : 26,25 MB
Release : 1995
Category : Power resources
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Page : 784 pages
File Size : 45,52 MB
Release : 1998
Category : Dissertation abstracts
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Page : 1248 pages
File Size : 44,61 MB
Release : 1994
Category : Physics
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Page : 994 pages
File Size : 32,59 MB
Release : 1995
Category : Aeronautics
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Page : 1228 pages
File Size : 23,53 MB
Release : 1992
Category : Physics
ISBN :
Author : Dalton D. Schnack
Publisher : Springer Science & Business Media
Page : 317 pages
File Size : 25,21 MB
Release : 2009-08-26
Category : Science
ISBN : 3642006876
Magnetohydrodynamics, or MHD, is a theoretical way of describing the statics and dynamics of electrically conducting uids. The most important of these uids occurring in both nature and the laboratory are ionized gases, called plasmas. These have the simultaneous properties of conducting electricity and being electrically charge neutral on almost all length scales. The study of these gases is called plasma physics. MHD is the poor cousin of plasma physics. It is the simplest theory of plasma dynamics. In most introductory courses, it is usually afforded a short chapter or lecture at most: Alfven ́ waves, the kink mode, and that is it. (Now, on to Landau damping!) In advanced plasma courses, such as those dealing with waves or kinetic theory, it is given an even more cursory treatment, a brief mention on the way to things more profound and interesting. (It is just MHD! Besides, real plasma phy- cists do kinetic theory!) Nonetheless, MHD is an indispensable tool in all applications of plasma physics.