Doppler Temperature and Particle Confinement Time Determined from Measurements of Hα-Line on a Tokamak Plasma in the JFT-2a Device

Nuclear fusion has arisen as an alternative energy to avoid carbon dioxide emissions, being the tokamak a promising nuclear fusion reactor that uses a magnetic field to confine plasma in the shape of a torus. However, different kinds of magnetohydrodynamic instabilities may affect tokamak plasma equilibrium, causing severe reduction of particle confinement and leading to plasma disruptions. In this sense, numerous efforts and resources have been devoted to seeking solutions for the different plasma control problems so as to avoid energy confinement time decrements in these devices. In particular, since the growth rate of the vertical instability increases with the internal inductance, lowering the internal inductance is a fundamental issue to address for the elongated plasmas employed within the advanced tokamaks currently under development. In this sense, this paper introduces a lumped parameter numerical model of the tokamak in order to design a novel robust sliding mode controller for the internal inductance using the transformer primary coil as actuator.

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Particle confinement of pellet-fuelled tokamak plasma

Nuclear Fusion ◽

10.1088/0029-5515/48/7/075006 ◽

2008 ◽

Vol 48 (7) ◽

pp. 075006 ◽

Cited By ~ 41

Author(s):

M. Valovič ◽

K. Axon ◽

L. Garzotti ◽

S. Saarelma ◽

A. Thyagaraja ◽

...

Keyword(s):

Tokamak Plasma ◽

Particle Confinement

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Numerical determination of the ambipolar electric field in a stellarator-reactor plasma

Journal of Plasma Physics ◽

10.1017/s0022377800014227 ◽

1989 ◽

Vol 42 (1) ◽

pp. 133-151 ◽

Cited By ~ 2

Author(s):

W. D. D'Haeseleer ◽

W. N. G. Hitchon ◽

J. L. Shohet

Keyword(s):

Electric Field ◽

Parametric Study ◽

Parameter Range ◽

Confinement Time ◽

Numerical Determination ◽

Algebraic Condition ◽

Order Of Magnitude ◽

Numerical Parametric Study ◽

Particle Confinement

A numerical parametric study of the radial ambipolar electric field in a stellarator reactor has been undertaken. With the numerical neoclassical code FLOCS (Flow Code for Stellarators), which is capable of handling both ions and electrons of all relevant kinetic energies, the radial ambipolar field (Er)AMB is determined from the algebraic condition that ion and electron fluxes are equal. As expected, the potential is of the same order of magnitude as the temperature. Somewhat surprisingly at first sight, however, the potential does not change much with the temperature (in the parameter range under consideration), being somewhat insensitive to moderate variations of T. An explanation for this behaviour is presented. Finally, the radial particle fluxes, consistent with the obtained (Er)AMB, and the particle confinement time are computed.

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