Collisionality - Revision history

Admin at 10:36, 26 January 2023

2023-01-26T10:36:27Z

← Older revision		Revision as of 12:36, 26 January 2023
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	Consider a test particle with charge ''q'', mass ''m'', and velocity ''v'' colliding with bulk particles with charge ''q'', mass ''m'', and thermal velocity ''v*''. Then the collision frequency ''ν = 1/τ<sub>coll</sub>'' is given by		Consider a test particle with charge ''q'', mass ''m'', and velocity ''v'' colliding with bulk particles with charge ''q'', mass ''m'', and thermal velocity ''v*''. Then the collision frequency ''ν = 1/τ<sub>coll</sub>'' is given by
	<ref>K. Miyamoto, ''Plasma Physics and Controlled Nuclear Fusion'', Springer-Verlag (2005) ISBN 3540242171</ref>		<ref>K. Miyamoto, ''Plasma Physics and Controlled Nuclear Fusion'', Springer-Verlag (2005) {{ISBN\|3540242171}}</ref>

	:<math>\nu = \left ( \frac{qq^n^}{\varepsilon_0 m}\right )^2 \frac{\ln \Lambda}{4\pi (m_r/m)v^3n^*}</math>		:<math>\nu = \left ( \frac{qq^n^}{\varepsilon_0 m}\right )^2 \frac{\ln \Lambda}{4\pi (m_r/m)v^3n^*}</math>

Admin: /* Dimensionless collisionality */

2011-08-31T10:52:41Z

Dimensionless collisionality

← Older revision		Revision as of 12:52, 31 August 2011
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	:<math>\nu^* = \frac{\rm connection~length}{\rm trapped~particle~mean~free~path}</math>		:<math>\nu^* = \frac{\rm connection~length}{\rm trapped~particle~mean~free~path}</math>

	See [[Connection length]].		See [[Connection length]]. The mean free path is estimated by the thermal velocity divided by the collision frequency, ''v<sub>th</sub> / ν''.

	== References ==		== References ==
	<references />		<references />

Admin: /* Dimensionless collisionality */

2010-07-30T12:31:31Z

Dimensionless collisionality

← Older revision		Revision as of 14:31, 30 July 2010
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	:<math>\nu^* = \frac{\rm connection~length}{\rm trapped~particle~mean~free~path}</math>		:<math>\nu^* = \frac{\rm connection~length}{\rm trapped~particle~mean~free~path}</math>

			See [[Connection length]].

	== References ==		== References ==
	<references />		<references />

Admin at 20:15, 25 July 2010

2010-07-25T20:15:37Z

← Older revision		Revision as of 22:15, 25 July 2010
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	assuming ''v > v'', where ''m<sub>r</sub> = mm/(m+m)'' is the reduced mass and ''n'' the bulk particle density.		assuming ''v > v'', where ''m<sub>r</sub> = mm/(m+m)'' is the reduced mass and ''n'' the bulk particle density.
	The factor ln Λ appears due to the accumulation of many small-angle collisions within a Debye sphere.		The factor ln Λ appears due to the accumulation of many small-angle collisions within a [[Debye length\|Debye sphere]].

	== Dimensionless collisionality ==		== Dimensionless collisionality ==

Admin: /* Dimensionless collisionality */

2010-07-25T17:11:40Z

Dimensionless collisionality

← Older revision		Revision as of 19:11, 25 July 2010
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	<ref>[http://dx.doi.org/10.1088/0029-5515/39/12/301 ITER Physics Basis, Nucl. Fusion '''39''' (1999) 2137]</ref>		<ref>[http://dx.doi.org/10.1088/0029-5515/39/12/301 ITER Physics Basis, Nucl. Fusion '''39''' (1999) 2137]</ref>

	:<math>\nu* = \frac{\rm connection~length}{\rm trapped~particle~mean~free~path}</math>		:<math>\nu^* = \frac{\rm connection~length}{\rm trapped~particle~mean~free~path}</math>

	== References ==		== References ==
	<references />		<references />

Admin at 17:10, 25 July 2010

2010-07-25T17:10:29Z

← Older revision		Revision as of 19:10, 25 July 2010
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	<ref>K. Miyamoto, ''Plasma Physics and Controlled Nuclear Fusion'', Springer-Verlag (2005) ISBN 3540242171</ref>		<ref>K. Miyamoto, ''Plasma Physics and Controlled Nuclear Fusion'', Springer-Verlag (2005) ISBN 3540242171</ref>

	:<math>\nu = \left ( \frac{qqn}{\varepsilon_0 m}\right )^2 \frac{\ln \Lambda}{4\pi (m_r/m)v^3n*}</math>		:<math>\nu = \left ( \frac{qq^n^}{\varepsilon_0 m}\right )^2 \frac{\ln \Lambda}{4\pi (m_r/m)v^3n^*}</math>

	assuming ''v > v'', where ''m<sub>r</sub> = mm/(m+m)'' is the reduced mass and ''n'' the bulk particle density.		assuming ''v > v'', where ''m<sub>r</sub> = mm/(m+m)'' is the reduced mass and ''n'' the bulk particle density.

Admin: Created page with 'In a plasma, the collision time ''τ_coll'' is defined as the time in which the trajectory of a (charged) particle undergoes a change of direction of 90 degrees. Due…'

2010-07-25T17:05:07Z

Created page with 'In a plasma, the collision time ''τcoll'' is defined as the time in which the trajectory of a (charged) particle undergoes a change of direction of 90 degrees. Due…'

New page

In a plasma, the collision time ''τcoll''
is defined as the time in which the trajectory of a (charged) particle undergoes a change of direction of 90 degrees.
Due to the long range of the Coulomb force, Coulomb interactions are typically small angle scattering events, so that this direction change typically requires a large number of interactions.

Consider a test particle with charge ''q'', mass ''m'', and velocity ''v'' colliding with bulk particles with charge ''q*'', mass ''m*'', and thermal velocity ''v*''. Then the collision frequency ''ν = 1/τcoll'' is given by
<ref>K. Miyamoto, ''Plasma Physics and Controlled Nuclear Fusion'', Springer-Verlag (2005) ISBN 3540242171</ref>

:<math>\nu = \left ( \frac{qq*n*}{\varepsilon_0 m}\right )^2 \frac{\ln \Lambda}{4\pi (m_r/m)v^3n*}</math>

assuming ''v > v*'', where ''mr = mm*/(m+m*)'' is the reduced mass and ''n*'' the bulk particle density.
The factor ln Λ appears due to the accumulation of many small-angle collisions within a Debye sphere.

== Dimensionless collisionality ==

The dimensionless collisionality ''ν*'' is defined as
<ref>[http://dx.doi.org/10.1088/0029-5515/39/12/301 ITER Physics Basis, Nucl. Fusion '''39''' (1999) 2137]</ref>

:<math>\nu* = \frac{\rm connection~length}{\rm trapped~particle~mean~free~path}</math>

== References ==
<references />

Collisionality - Revision history

Admin at 10:36, 26 January 2023

Admin: /* Dimensionless collisionality */

Admin: /* Dimensionless collisionality */

Admin at 20:15, 25 July 2010

Admin: /* Dimensionless collisionality */

Admin at 17:10, 25 July 2010

Admin: Created page with 'In a plasma, the collision time ''τcoll'' is defined as the time in which the trajectory of a (charged) particle undergoes a change of direction of 90 degrees. Due…'

Admin: Created page with 'In a plasma, the collision time ''τ_coll'' is defined as the time in which the trajectory of a (charged) particle undergoes a change of direction of 90 degrees. Due…'