Profile consistency: Difference between revisions

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Updated reference links
(Updated reference links)
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<ref>Yu.N. Dnestrovsky et al, Sov. J. Plasma Phys. '''16''' (1990) 120</ref>
<ref>Yu.N. Dnestrovsky et al, Sov. J. Plasma Phys. '''16''' (1990) 120</ref>
The resulting (stiff) profiles are known as ''canonical'' profiles.
The resulting (stiff) profiles are known as ''canonical'' profiles.
<ref>[http://dx.doi.org/10.1134/1.1520282 Yu.N. Dnestrovsky et al, ''Canonical profiles in tokamak plasmas with an arbitrary cross section'', Plasma Physics Reports '''28''', 11 (2002) 887-899]</ref>
<ref>Yu.N. Dnestrovsky et al, ''Canonical profiles in tokamak plasmas with an arbitrary cross section'', [[doi:10.1134/1.1520282|Plasma Physics Reports '''28''', 11 (2002) 887-899]]</ref>
This phenomenology is due to plasma [[Self-Organised Criticality|self-organisation]],
This phenomenology is due to plasma [[Self-Organised Criticality|self-organisation]],
<ref>[http://dx.doi.org/10.1134/1.1992581 Yu.N. Dnestrovsky et al, ''Self-organization of plasma in tokamaks'', Plasma Physics Reports '''31''', 7 (2005) 529-553]</ref>
<ref>Yu.N. Dnestrovsky et al, ''Self-organization of plasma in tokamaks'', [[doi:10.1134/1.1992581|Plasma Physics Reports '''31''', 7 (2005) 529-553]]</ref>
i.e., the feedback mechanism regulating the profiles (by turbulence) is often dominant over the various source terms.
i.e., the feedback mechanism regulating the profiles (by turbulence) is often dominant over the various source terms.
<ref>[http://link.aip.org/link/?PHPAEN/8/4096/1 F. Jenko et al, ''Critical gradient formula for toroidal electron temperature gradient modes'', Phys. Plasmas '''8''' (2001) 4096]</ref>
<ref>F. Jenko et al, ''Critical gradient formula for toroidal electron temperature gradient modes'', [http://link.aip.org/link/?PHPAEN/8/4096/1 Phys. Plasmas '''8''' (2001) 4096]</ref>


== Observations ==
== Observations ==
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=== [[Tokamak]]s ===
=== [[Tokamak]]s ===


* TFTR <ref>[http://dx.doi.org/10.1088/0029-5515/26/7/002 E.D. Fredrickson, J.D. Callen, et al., ''Heat pulse propagation studies in TFTR'', Nucl. Fusion '''26''' (1986) 849]</ref>
* TFTR <ref>E.D. Fredrickson, J.D. Callen, et al., ''Heat pulse propagation studies in TFTR'', [[doi:10.1088/0029-5515/26/7/002|Nucl. Fusion '''26''' (1986) 849]]</ref>
* ASDEX <ref>[http://dx.doi.org/10.1088/0029-5515/32/1/I07 G. Becker, ''Electron temperature profile invariance in OH, L- and H-mode plasmas and consequences for the anomalous transport'', Nucl. Fusion '''32''' (1992) 81]</ref>
* ASDEX <ref>G. Becker, ''Electron temperature profile invariance in OH, L- and H-mode plasmas and consequences for the anomalous transport'', [[doi:10.1088/0029-5515/32/1/I07|Nucl. Fusion '''32''' (1992) 81]]</ref>
* Various devices <ref>[http://dx.doi.org/10.1088/0741-3335/35/10/002 F. Wagner and U. Stroth, ''Transport in toroidal devices-the experimentalist's view'', Plasma Phys. Control. Fusion '''35''' (1993) 1321]</ref><ref>[http://dx.doi.org/10.1088/0741-3335/43/12A/325 F. Ryter, C. Angioni, et al., ''Experimental studies of electron transport'', Plasma Phys. Control. Fusion '''43''' (2001) A323]</ref>
* Various devices <ref>F. Wagner and U. Stroth, ''Transport in toroidal devices-the experimentalist's view'', [[doi:10.1088/0741-3335/35/10/002|Plasma Phys. Control. Fusion '''35''' (1993) 1321]]</ref><ref>F. Ryter, C. Angioni, et al., ''Experimental studies of electron transport'', [[doi:10.1088/0741-3335/43/12A/325|Plasma Phys. Control. Fusion '''43''' (2001) A323]]</ref>


=== [[Stellarator]]s ===
=== [[Stellarator]]s ===


* W7-AS <ref>[http://dx.doi.org/10.1088/0741-3335/40/1/002 U. Stroth, ''A comparative study of transport in stellarators and tokamaks'', Plasma Phys. Control. Fusion '''40''' (1998) 9]</ref>
* W7-AS <ref>U. Stroth, ''A comparative study of transport in stellarators and tokamaks'', [[doi:10.1088/0741-3335/40/1/002|Plasma Phys. Control. Fusion '''40''' (1998) 9]]</ref>
* Various devices <ref>[http://www-pub.iaea.org/MTCD/Meetings/FEC2008/th_p8-24.pdf Yu.N. Dnestrovsky et al, IAEA Fusion Energy Conference, Geneva (2008) TH/P8-24]</ref>
* Various devices <ref>Yu.N. Dnestrovsky et al, [http://www-pub.iaea.org/MTCD/Meetings/FEC2008/th_p8-24.pdf IAEA Fusion Energy Conference, Geneva (2008) TH/P8-24]</ref>


== Proposed explanations ==
== Proposed explanations ==


The phenomenon is not fully understood, but attempts at explanation have been made. These include:
The phenomenon is not fully understood, but attempts at explanation have been made. These include:
* Marginal stability <ref>[[doi:10.1063/1.871063|P.H. Diamond and T.S. Hahm, ''On the dynamics of turbulent transport near marginal stability'', Phys. Plasmas '''2''' (1995) 3640]]</ref>
* Marginal stability <ref>P.H. Diamond and T.S. Hahm, ''On the dynamics of turbulent transport near marginal stability'', [[doi:10.1063/1.871063|Phys. Plasmas '''2''' (1995) 3640]]</ref>
* Critical gradient models <ref>[[doi:10.1088/0741-3335/44/8/301|F. Imbeaux and X. Garbet, ''Analytical solutions for the propagation of heat pulses with temperature gradient length-dependent diffusion coefficient'', Plasma Phys. Control. Fusion '''44''' (2002) 1425]]</ref>
* Critical gradient models <ref>F. Imbeaux and X. Garbet, ''Analytical solutions for the propagation of heat pulses with temperature gradient length-dependent diffusion coefficient'', [[doi:10.1088/0741-3335/44/8/301|Plasma Phys. Control. Fusion '''44''' (2002) 1425]]</ref>
* [[Heat pinch|Energy pinch]] <ref>[[doi:10.1103/PhysRevLett.85.4534|P. Mantica, G. Gorini, G.M.D. Hogeweij, N.J. Lopes Cardozo, and A.M.R. Schilham, ''Heat Convection and Transport Barriers in Low-Magnetic-Shear Rijnhuizen Tokamak Project Plasmas'', Phys. Rev. Lett. '''85''' (2000) 4534–4537]]</ref><ref>[[doi:10.1063/1.1951667|X. Garbet, N. Dubuit, E. Asp, Y. Sarazin, C. Bourdelle, P. Ghendrih, and G.T. Hoang, ''Turbulent fluxes and entropy production rate'', Phys. Plasmas '''12''' (2005) 082511]]</ref><ref>[[doi:10.1103/PhysRevLett.95.185002|P. Mantica, A. Thyagaraja, J. Weiland, G.M.D. Hogeweij, and P.J. Knight, ''Heat Pinches in Electron-Heated Tokamak Plasmas: Theoretical Turbulence Models versus Experiments'', Phys. Rev. Lett. '''95''' (2005) 185002]]</ref>
* [[Heat pinch|Energy pinch]] <ref>P. Mantica, G. Gorini, G.M.D. Hogeweij, N.J. Lopes Cardozo, and A.M.R. Schilham, ''Heat Convection and Transport Barriers in Low-Magnetic-Shear Rijnhuizen Tokamak Project Plasmas'', [[doi:10.1103/PhysRevLett.85.4534|Phys. Rev. Lett. '''85''' (2000) 4534–4537]]</ref><ref>X. Garbet, N. Dubuit, E. Asp, Y. Sarazin, C. Bourdelle, P. Ghendrih, and G.T. Hoang, ''Turbulent fluxes and entropy production rate'', [[doi:10.1063/1.1951667|Phys. Plasmas '''12''' (2005) 082511]]</ref><ref>P. Mantica, A. Thyagaraja, J. Weiland, G.M.D. Hogeweij, and P.J. Knight, ''Heat Pinches in Electron-Heated Tokamak Plasmas: Theoretical Turbulence Models versus Experiments'', [[doi:10.1103/PhysRevLett.95.185002|Phys. Rev. Lett. '''95''' (2005) 185002]]</ref>
* [[Self-Organised Criticality]]
* [[Self-Organised Criticality]]
* Turbulent equipartition <ref>[[doi:10.1063/1.2141396|V. Naulin, A.H. Nielsen, and J. Juul Rasmussen, ''Turbulence spreading, anomalous transport, and pinch effect'', Phys. Plasmas '''12''' (2005) 122306]]</ref><ref>[[doi:10.1088/0029-5515/51/8/083006|Lu Wang and P.H. Diamond, ''Kinetic theory of the turbulent energy pinch in tokamak plasmas'', Nucl. Fusion '''51''' (2011) 083006]]</ref>
* Turbulent equipartition <ref>V. Naulin, A.H. Nielsen, and J. Juul Rasmussen, ''Turbulence spreading, anomalous transport, and pinch effect'', [[doi:10.1063/1.2141396|Phys. Plasmas '''12''' (2005) 122306]]</ref><ref>Lu Wang and P.H. Diamond, ''Kinetic theory of the turbulent energy pinch in tokamak plasmas'', [[doi:10.1088/0029-5515/51/8/083006|Nucl. Fusion '''51''' (2011) 083006]]</ref>


== Quantification methods ==
== Quantification methods ==
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It is customary to introduce an ad-hoc transport model with a critical gradient (sharply enhanced transport above a critical value of the local gradient) to attempt to quantify the 'criticality' of transport:
It is customary to introduce an ad-hoc transport model with a critical gradient (sharply enhanced transport above a critical value of the local gradient) to attempt to quantify the 'criticality' of transport:
<ref>[http://dx.doi.org/10.1088/0741-3335/43/11/306 F. Imbeaux, F. Ryter, and X. Garbet, ''Modelling of ECH modulation experiments in ASDEX Upgrade with an empirical critical temperature gradient length transport model'', Plasma Phys. Control. Fusion '''43''' (2001) 1503]</ref>
<ref>F. Imbeaux, F. Ryter, and X. Garbet, ''Modelling of ECH modulation experiments in ASDEX Upgrade with an empirical critical temperature gradient length transport model'', [[doi:10.1088/0741-3335/43/11/306|Plasma Phys. Control. Fusion '''43''' (2001) 1503]]</ref>
<ref>[http://dx.doi.org/10.1088/0741-3335/46/9/002 X. Garbet, P. Mantica, F. Ryter, et al., ''Profile stiffness and global confinement'', Plasma Phys. Control. Fusion '''46''' (2004) 1351]</ref>
<ref>X. Garbet, P. Mantica, F. Ryter, et al., ''Profile stiffness and global confinement'', [[doi:10.1088/0741-3335/46/9/002|Plasma Phys. Control. Fusion '''46''' (2004) 1351]]</ref>


:<math>\chi = \chi_0 + \chi_1 \xi \left ( \frac{R}{L_T}-\frac{R}{L_{T,crit}}\right )^\alpha H\left ( \frac{R}{L_T}-\frac{R}{L_{T,crit}}\right )</math>
:<math>\chi = \chi_0 + \chi_1 \xi \left ( \frac{R}{L_T}-\frac{R}{L_{T,crit}}\right )^\alpha H\left ( \frac{R}{L_T}-\frac{R}{L_{T,crit}}\right )</math>
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However, it is possible to devise methods for the objective quantification of profile stiffness that do not depend so much on the introduction of any ad-hoc model, simply by making this idea of stiffness explicit (i.e., by measuring the response of the gradient to a change in drive or heat source).
However, it is possible to devise methods for the objective quantification of profile stiffness that do not depend so much on the introduction of any ad-hoc model, simply by making this idea of stiffness explicit (i.e., by measuring the response of the gradient to a change in drive or heat source).
<ref>[http://www.jspf.or.jp/PFR/PFR_articles/pfr2008S1/pfr2008_03-S1070.html B.Ph. van Milligen et al, ''Quantifying profile stiffness'', Plasma and Fusion Research, '''3''' (2008) S1070]</ref>
<ref>B.Ph. van Milligen et al, ''Quantifying profile stiffness'', [http://www.jspf.or.jp/PFR/PFR_articles/pfr2008S1/pfr2008_03-S1070.html Plasma and Fusion Research, '''3''' (2008) S1070]</ref>


The [[:Wikipedia:Stiffness|general definition of stiffness of a system]] is  
The [[:Wikipedia:Stiffness|general definition of stiffness of a system]] is  

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