Ion Temperature Gradient instability - Revision history

Sorah at 17:21, 28 June 2021

2021-06-28T17:21:54Z

← Older revision		Revision as of 19:21, 28 June 2021
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	The instability occurs due to the nature of Grad-B drift. The Grad-B drift velocity of a particle (caused by a gradient in the magnetic field) is proportional to the particle's kinetic energy. Hotter particles drift further than colder particles.		The instability occurs due to the nature of Grad-B drift. The Grad-B drift velocity of a particle (caused by a gradient in the magnetic field) is proportional to the particle's kinetic energy. Hotter particles drift further than colder particles.

	Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates a electric field. This electric field creates an <math>E\times B</math> drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.		Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates an electric field. This electric field creates an <math>E\times B</math> drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.

	Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the <math>E\times B</math> drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.		Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the <math>E\times B</math> drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.

Admin: Added a reference (more needed)

2016-10-19T13:33:46Z

Added a reference (more needed)

← Older revision		Revision as of 15:33, 19 October 2016
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	The ion temperature gradient (ITG) instability is a microinstability in [[tokamak]]s relevant to turbulence and the associated [[anomalous transport]].		The ion temperature gradient (ITG) instability<ref> P. N. Guzdar, Liu Chen, W. M. Tang and P. H. Rutherford, ''Ion‐temperature‐gradient instability in toroidal plasmas'' [[doi:10.1063/1.864182\|Phys. Fluids '''26''' (1983) 673]]</ref> is a microinstability in [[tokamak]]s relevant to turbulence and the associated [[anomalous transport]].

	The instability occurs due to the nature of Grad-B drift. The Grad-B drift velocity of a particle (caused by a gradient in the magnetic field) is proportional to the particle's kinetic energy. Hotter particles drift further than colder particles.		The instability occurs due to the nature of Grad-B drift. The Grad-B drift velocity of a particle (caused by a gradient in the magnetic field) is proportional to the particle's kinetic energy. Hotter particles drift further than colder particles.
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	* [[Plasma instability]]		* [[Plasma instability]]

			== References ==
			<references/>

Admin: Added some wiki links

2016-10-19T13:16:50Z

Added some wiki links

← Older revision		Revision as of 15:16, 19 October 2016
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	The ion temperature gradient (ITG) instability is a microinstability in ~~tokamaks~~ relevant to turbulence and the associated anomalous transport.		The ion temperature gradient (ITG) instability is a microinstability in [[tokamak]]s relevant to turbulence and the associated [[anomalous transport]].

	The instability occurs due to the nature of Grad-B drift. The Grad-B drift velocity of a particle (caused by a gradient in the magnetic field) is proportional to the particle's kinetic energy. Hotter particles drift further than colder particles.		The instability occurs due to the nature of Grad-B drift. The Grad-B drift velocity of a particle (caused by a gradient in the magnetic field) is proportional to the particle's kinetic energy. Hotter particles drift further than colder particles.

	Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates a electric field. This electric field creates an ~~ExB~~ drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.		Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates a electric field. This electric field creates an <math>E\times B</math> drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.

	Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ~~ExB~~ drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.		Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the <math>E\times B</math> drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.

	See the figure for a graphical explanation.		See the figure for a graphical explanation.

	[[File:ITG.png]]		[[File:ITG.png\|600px\|thumb\|center\|ITG mechanism]]

			== See also ==

			* [[Plasma instability]]

Alschei at 14:01, 18 October 2016

2016-10-18T14:01:03Z

← Older revision		Revision as of 16:01, 18 October 2016
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	Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates a electric field. This electric field creates an ExB drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.		Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates a electric field. This electric field creates an ExB drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.

			Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.

	See the figure for a graphical explanation.		See the figure for a graphical explanation.

	[[File:ITG.png ~~\| width=10 \| image-width=10~~]]		[[File:ITG.png]]

	Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.

Alschei at 13:58, 18 October 2016

2016-10-18T13:58:23Z

← Older revision		Revision as of 15:58, 18 October 2016
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	See the figure for a graphical explanation.		See the figure for a graphical explanation.

	[[File:ITG.png\|width=~~100px~~\|~~Caption A cartoon sketch of the Ion Temperature Gradient instability~~]]		[[File:ITG.png \| width=10 \| image-width=10]]

	Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.		Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.

Alschei at 13:51, 18 October 2016

2016-10-18T13:51:26Z

← Older revision		Revision as of 15:51, 18 October 2016
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	See the figure for a graphical explanation.		See the figure for a graphical explanation.

	[[File:ITG.png]]		[[File:ITG.png\|width=100px\|Caption A cartoon sketch of the Ion Temperature Gradient instability]]

	Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.		Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.

Alschei at 13:48, 18 October 2016

2016-10-18T13:48:14Z

← Older revision		Revision as of 15:48, 18 October 2016
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	Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates a electric field. This electric field creates an ExB drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.		Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates a electric field. This electric field creates an ExB drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.

	See the figure ~~to see the geometric setup~~.		See the figure for a graphical explanation.

			[[File:ITG.png]]

	Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.		Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.

	~~[[File:ITG.eps]]~~

Alschei: Created page with "The ion temperature gradient (ITG) instability is a microinstability in tokamaks relevant to turbulence and the associated anomalous transport. The instability occurs due to ..."

2016-10-18T13:44:14Z

Created page with "The ion temperature gradient (ITG) instability is a microinstability in tokamaks relevant to turbulence and the associated anomalous transport. The instability occurs due to ..."

New page

The ion temperature gradient (ITG) instability is a microinstability in tokamaks relevant to turbulence and the associated anomalous transport.

The instability occurs due to the nature of Grad-B drift. The Grad-B drift velocity of a particle (caused by a gradient in the magnetic field) is proportional to the particle's kinetic energy. Hotter particles drift further than colder particles.

Hence, if a temperature gradient is aligned with a magnetic field gradient (as occurs in a tokamak), particles in the hotter region will drift further. If there is a perturbation in the temperature gradient, then the difference in drift velocities will create charge separation. The charge separation creates a electric field. This electric field creates an ExB drift which increases the perturbation's amplitude. The positive-feedback nature of this loop leads to exponential growth of the instability.

See the figure to see the geometric setup.

Note that if the temperature gradient is anti-parallel to the magnetic field gradient, the ExB drift will suppress the perturbation rather than increase it. This situation occurs on the inner, "good-curvature" side of the tokamak.

[[File:ITG.eps]]