The effect of biased limiter on the magnetic island width in tokamak plasma

AbstractIn this work the effects of Cold Biased Limiter (CBL) and Emissive Biased Limiter (EBL) have been individually investigated, in both positive and negative polarities, on the width and frequency of magnetic islands. The effects were examined using singular value decomposition and wavelet techniques on mirnov coil signals. The results show that the application of EBL with both positive and negative polarities has been more effective on plasma stability compared with CBL. Comparing different polarities of CBL and EBL revealed that the positive polarity was more effective on the width of magnetic islands than negative polarity. The greatest impact occurs during EBL with positive polarity, in which reduction is observed in both width of magnetic islands and emission of Hα radiation. Besides, intensity and frequency of magnetic islands are reduced from 50 to 25 kHz in around 1 ms after bias application. Meanwhile, the minimal effect on width and frequency of magnetic field occurs in CBL with negative polarity.

Download Full-text

Control of Heat and Mass Transfers Due to Tearing Mode-Based Magnetic Islands During Disruption Phase in IR-T1 Tokamak

Journal of Heat Transfer ◽

10.1115/1.4039012 ◽

2018 ◽

Vol 140 (6) ◽

Author(s):

R. Sadeghi ◽

A. Salar Elahi ◽

M. Ghoranneviss ◽

M. K. Salem

Keyword(s):

Energy Content ◽

Singular Value ◽

Mode Analysis ◽

Magnetic Fluctuations ◽

Magnetic Islands ◽

Tearing Mode ◽

Tearing Modes ◽

Complete Disruption ◽

Value Decomposition ◽

Mass Transfers

A structural change of perturbed magnetic configurations (such as magnetic islands) during disruption phase in IR-T1 tokamak was studied. The singular value decomposition (SVD) mode analysis and the (m,n) modes identification were presented. We also presented the SVD technique to analyze the tokamak magnetic fluctuations, time evolution of magnetohydrodynamics (MHD) modes, spatial structure of each time vector, and the energy content of each modes. We also considered different scenarios for plasma from steady-state to predisruption, complete disruption, creation of tearing modes, and finally magnetic islands.

Download Full-text

Singular Value Decomposition Analysis of Multichannel Electron Cyclotron Emission Signals of Tokamak Plasma

Japanese Journal of Applied Physics ◽

10.1143/jjap.42.l329 ◽

2003 ◽

Vol 42 (Part 2, No. 3B) ◽

pp. L329-L331 ◽

Cited By ~ 1

Author(s):

Akihiko Isayama ◽

Naofumi Iwama ◽

Yohsuke Hosoda ◽

Shinsuke Satake ◽

Nobuaki Isei ◽

...

Keyword(s):

Singular Value Decomposition ◽

Decomposition Analysis ◽

Singular Value ◽

Electron Cyclotron ◽

Tokamak Plasma ◽

Electron Cyclotron Emission ◽

Singular Value Decomposition Analysis ◽

Cyclotron Emission ◽

Value Decomposition

Download Full-text

Singular Value Decomposition Combined With Analytical Method for Tokamak Plasma Tomography

Journal of Fusion Energy ◽

10.1007/s10894-009-9240-z ◽

2009 ◽

Vol 29 (2) ◽

pp. 109-112 ◽

Cited By ~ 1

Author(s):

Tahereh Mohammadnejad ◽

Pejman Khorshid ◽

Jalaleddin Izadian ◽

Kurosh Javidan

Keyword(s):

Singular Value Decomposition ◽

Analytical Method ◽

Singular Value ◽

Tokamak Plasma ◽

Plasma Tomography ◽

Value Decomposition

Download Full-text

Human Event-Related Potentials to Higher-Order Acoustic Spatial Changes

Journal of Psychophysiology ◽

10.1027//0269-8803.16.2.114 ◽

2002 ◽

Vol 16 (2) ◽

pp. 114-118 ◽

Cited By ~ 1

Author(s):

Timo Ruusuvirta ◽

Heikki Hämäläinen

Keyword(s):

Working Memory ◽

Mismatch Negativity ◽

Spatial Information ◽

Free Field ◽

Event Related Potentials ◽

Negative Polarity ◽

Positive Polarity ◽

Spatial Changes ◽

Related Potentials ◽

Human Event

Abstract Human event-related potentials (ERPs) to a tone continuously alternating between its two spatial loci of origin (middle-standards, left-standards), to repetitions of left-standards (oddball-deviants), and to the tones originally representing these repetitions presented alone (alone-deviants) were recorded in free-field conditions. During the recordings (Fz, Cz, Pz, M1, and M2 referenced to nose), the subjects watched a silent movie. Oddball-deviants elicited a spatially diffuse two-peaked deflection of positive polarity. It differed from a deflection elicited by left-standards and commenced earlier than a prominent deflection of negative polarity (N1) elicited by alone-deviants. The results are discussed in the context of the mismatch negativity (MMN) and previous findings of dissociation between spatial and non-spatial information in auditory working memory.

Download Full-text