Scaling law: Difference between revisions

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The main performance parameter that is subjected to scaling law analysis is the [[Energy confinement time|energy confinement time]], &tau;<sub>E</sub>.
The main performance parameter that is subjected to scaling law analysis is the [[Energy confinement time|energy confinement time]], &tau;<sub>E</sub>.
The following are some of the most-used scalings for tokamaks:
The energy confinement time is expressed in engineering variables:
<ref name="ITER">[http://dx.doi.org/10.1088/0029-5515/39/12/301 ITER Physics Expert Groups et al, ''ITER Physics Basis, Chapter 1'', Nucl. Fusion '''39''' (1999) 2137] and [http://dx.doi.org/10.1088/0029-5515/39/12/302 Ibid., ''Chapter 2'']</ref>
* L-mode scaling (ITER89-P)
:<math>\tau_E^L = 0.048 I_M^{0.85} R_0^{1.2} a^{0.3} \kappa^{0.5} \bar n_{20}^{0.1} B_0^{0.2} A^{0.5} P_M^{-0.5}</math>


* ELMy [[H-mode]] scaling (IPB98(y,2))
:<math>\tau_E = C I^{\alpha_I} B^{\alpha_B} \overline{n}^{\alpha_n} P^{\alpha_P} R^{\alpha_R} \kappa^{\alpha_\kappa} \epsilon^{\alpha_\epsilon} S_{cr}^{\alpha_S} M^{\alpha_M}</math>
:<math>\tau_E^H = 0.145 I_M^{0.93} R_0^{1.39} a^{0.58} \kappa^{0.78} \bar n_{20}^{0.41} B_0^{0.15} A^{0.19} P_M^{-0.69}</math>


where ''I<sub>M</sub>'' is given in MA, ''P<sub>M</sub>'' in MW, ''n<sub>20</sub>'' in 10<sup>20</sup> m<sup>-3</sup>, and ''B<sub>0</sub>'' in T.
where
* I (MA) is the plasma current
* B (T) is the toroidal magnetic field
* <math>\overline{n}</math> (10<sup>19</sup> m<sup>-3</sup>) is the central line averaged density
* P (MW) is the absorbed power
* R (m) is the major radius
* &kappa; is the elongation
* &epsilon; is the inverse aspect ratio
* S<sub>cr</sub> is the cross sectional area
* M is the hydrogen isotope mass


For stellarators, a similar scaling has been obtained (ISS).
The following tables shows some of the most generally used sets of scaling parameters for the ELMy [[H-mode]] and L-mode.
<ref name="ITER">ITER Physics Expert Groups et al, ''ITER Physics Basis, Chapter 1'', [[doi:10.1088/0029-5515/39/12/301|Nucl. Fusion '''39''' (1999) 2137]] and
[[doi:10.1088/0029-5515/39/12/302|Ibid., ''Chapter 2'']]</ref>
<ref>J.G. Cordey, J.A. Snipes, M. Greenwald, et al., IAEA 20th Fusion Energy Conference, Vilamoura, Portugal, 2004, paper IAEA-CN-116/IT/P3-32, submitted to Nucl. Fusion.</ref>
<ref>P.N. Yushmanov, T. Takizuka, K.S. Riedel, et al., [[doi:10.1088/0029-5515/30/10/001|Nucl. Fusion 30 (1990) 1999]]</ref>
<ref>S.M. Kaye, et al., [[doi:10.1088/0029-5515/37/9/I10|Nucl. Fusion 37 (1997) 1303]]</ref>
 
{| class="wikitable sortable" border="1" cellpadding="4" cellspacing="0"
|+
|- style="background:#FFDEAD;"
!Scaling
!<math>C\times10^3</math>
!<math>\alpha_I</math>
!<math>\alpha_B</math>
!<math>\alpha_n</math>
!<math>\alpha_P</math>
!<math>\alpha_R</math>
!<math>\alpha_\kappa</math>
!<math>\alpha_\epsilon</math>
!<math>\alpha_S</math>
!<math>\alpha_M</math>
|-
|ITERH-98P(y,2)
|56.2
|0.93
|0.15
|0.41
| -0.69
|1.97
|0.78
|0.58
| -
|0.19
|-
|ITPAH-04P(y,1)
|22.8
|0.86
|0.21
|0.40
| -0.65
|0.32
| -
| -0.99
|0.84
|0.08
|-
|ITPAH-04P(y,2)
|19.8
|0.85
|0.17
|0.26
| -0.45
| -0.04
| -
| -1.25
|0.82
|0.11
|-
|ITPAH-04P(y,3)
|88.0
|0.90
| -
|0.30
| -0.47
|1.73
| -
|0.43
| -
| -
|-
|ITER-89P
|48
|0.85
|0.20
|0.10
| -0.50
|1.50
|0.50
|0.30
| -
|0.50
|-
|ITERL-96P(th)
|23
|0.96
|0.03
|0.40
| -0.73
|1.83
|0.64
| -0.06
| -
|0.20
|-
|}
 
For [[stellarator]]s, a similar scaling has been obtained (ISS).
<ref>[http://www.ipp.mpg.de/ISS ISS-IPP] and [http://iscdb.nifs.ac.jp/ ISS-NIFS] homepages</ref>
<ref>[http://www.ipp.mpg.de/ISS ISS-IPP] and [http://iscdb.nifs.ac.jp/ ISS-NIFS] homepages</ref>
<ref>[http://dx.doi.org/10.1088/0029-5515/47/9/025 A. Dinklage et al, ''Physical model assessment of the energy confinement time scaling in stellarators'', Nuclear Fusion '''47''', 9 (2007) 1265-1273]</ref>
<ref>[http://dx.doi.org/10.1088/0029-5515/47/9/025 A. Dinklage et al, ''Physical model assessment of the energy confinement time scaling in stellarators'', Nuclear Fusion '''47''', 9 (2007) 1265-1273]</ref>