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Turbulence and transport suppression scaling with flow shear on the Large Plasma Devicea)
a)Paper TI2 2, Bull. Am. Phys. Soc. , 291 (2012).
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1.
1. K. Burrell, Phys. Plasmas 4, 1499 (1997).
http://dx.doi.org/10.1063/1.872367
2.
2. K. Burrell, Phys. Plasmas 6, 4418 (1999).
http://dx.doi.org/10.1063/1.873728
3.
3. P. Terry, Rev. Mod. Phys. 72, 109 (2000).
http://dx.doi.org/10.1103/RevModPhys.72.109
4.
4. G. Van Oost, J. Adamek, V. Antoni, P. Balan, J. A. Boedo, P. Devynck, I. Duran, L. Eliseev, J. P. Gunn, M. Hron, C. Ionita, S. Jachmich, G. S. Kirnev, E. Martines, A. Melnikov, R. Schrittwieser, C. Silva, J. Stockel, M. Tendler, C. Varandas, M. Van Schoor, V. Vershkov, and R. R. Weynants, Plasma. Phys. Controlled Fusion 45, 621 (2003).
http://dx.doi.org/10.1088/0741-3335/45/5/308
5.
5. O. Sakai, Y. Yasaka, and R. Itatani, Phys. Rev. Lett. 70, 4071 (1993).
http://dx.doi.org/10.1103/PhysRevLett.70.4071
6.
6. J. E. Maggs, T. A. Carter, and R. J. Taylor, Phys. Plasmas 14, 052507 (2007).
http://dx.doi.org/10.1063/1.2722302
7.
7. T. A. Carter and J. E. Maggs, Phys. Plasmas 16, 012304 (2009).
http://dx.doi.org/10.1063/1.3059410
8.
8. D. A. Schaffner, T. A. Carter, G. D. Rossi, D. S. Guice, J. E. Maggs, S. Vincena, and B. Friedman, Phys. Rev. Lett. 109, 135002 (2012).
http://dx.doi.org/10.1103/PhysRevLett.109.135002
9.
9. K. H. Burrell, T. N. Carlstrom, E. J. Doyle, D. Finkenthal, P. Gohil, R. J. Groebner, D. L. Hillis, J. Kim, H. Matsumoto, R. A. Moyer, T. H. Osborne, C. L. Rettig, W. A. Peebles, T. L. Rhodes, H. St. John, R. D. Stambaugh, M. R. Wade, and J. G. Watkins, Plasma. Phys. Controlled Fusion 34, 1859 (1992).
http://dx.doi.org/10.1088/0741-3335/34/13/014
10.
10. F. Wagner, Plasma Phys. Controlled Fusion 49, B1 (2007).
http://dx.doi.org/10.1088/0741-3335/49/12B/S01
11.
11. R. J. Taylor, M. L. Brown, B. D. Fried, H. Grote, J. R. Liberati, G. J. Morales, P. Pribyl, D. Darrow, and M. Ono, Phys. Rev. Lett. 63, 2365 (1989).
http://dx.doi.org/10.1103/PhysRevLett.63.2365
12.
12. R. R. Weynants, G. Van Oost, G. Bertschinger, J. Boedo, P. Brys, T. Delvigne, K. H. Dippel, F. Durodie, H. Euringer, K. H. Finken, D. S. Gray, J. D. Hey, D. L. Hillis, J. T. Hogan, L. Konan, R. Leners, A. M. Messian, A. Pospieszczyck, U. Samm, R. P. Schorn, B. Schweer, G. Telesca, R. Vannieuwenhove, and P. E. Vandenplas, Nucl. Fusion 32, 837 (1992).
http://dx.doi.org/10.1088/0029-5515/32/5/I10
13.
13. R. R. Weynants, S. Jachmich, and G. Van Oost, Plasma. Phys. Controlled Fusion 40, 635 (1998).
http://dx.doi.org/10.1088/0741-3335/40/5/013
14.
14. J. Boedo, D. Gray, S. Jachmich, R. Conn, G. P. Terry, G. Tynan, G. Van Oost, R. R. Weynants, and TEXTOR Team, Nucl. Fusion 40(7), 1397 (2000).
http://dx.doi.org/10.1088/0029-5515/40/7/309
15.
15. J. A. Boedo, D. S. Gray, P. W. Terry, S. Jachmich, G. R. Tynan, R. W. Conn, and TEXTOR-94 Team, Nucl. Fusion 42, 117 (2002).
http://dx.doi.org/10.1088/0029-5515/42/2/301
16.
16. H. Biglari, P. H. Diamond, and P. W. Terry, Phys. Fluids B. 2, 1 (1990).
http://dx.doi.org/10.1063/1.859529
17.
17. K. C. Shaing, E. C. Crume, and W. A. Houlberg, Phys. Fluids B 2(6), 1492 (1990).
http://dx.doi.org/10.1063/1.859473
18.
18. Y. Z. Zhang and S. M. Mahajan, Phys. Fluids B 4, 1385 (1992).
http://dx.doi.org/10.1063/1.860095
19.
19. Y. Z. Zhang and S. M. Mahajan, Phys. Fluids B 5(7), 2000 (1993).
http://dx.doi.org/10.1063/1.860788
20.
20. A. S. Ware, P. W. Terry, P. H. Diamond, and B. A. Carreras, Plasma Phys. Controlled Fusion 38, 1343 (1996).
http://dx.doi.org/10.1088/0741-3335/38/8/034
21.
21. A. S. Ware, P. W. Terry, B. A. Carreras, and P. H. Diamond, Phys. Plasmas 5, 173 (1998).
http://dx.doi.org/10.1063/1.872685
22.
22. P. W. Terry, D. E. Newman, and A. S. Ware, Phys. Rev. Lett. 87, 185001 (2001).
http://dx.doi.org/10.1103/PhysRevLett.87.185001
23.
23. E.-J. Kim and P. H. Diamond, Phys. Rev. Lett. 91(7), 075001 (2003).
http://dx.doi.org/10.1103/PhysRevLett.91.075001
24.
24. E.-J. Kim, P. H. Diamond, and T. S. Hahm, Phys. Plasmas 11(10), 4554 (2004).
http://dx.doi.org/10.1063/1.1783315
25.
25. A. P. L. Newton and E.-J. Kim, Phys. Plasmas 18, 052305 (2011).
http://dx.doi.org/10.1063/1.3582097
26.
26. W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991).
http://dx.doi.org/10.1063/1.1142175
27.
27. T. S. Hahm, Phys. Plasmas 1, 2940 (1994).
http://dx.doi.org/10.1063/1.870534
28.
28. M. Leconte, P. Beyer, S. Benkadda, and X. Garbet, Phys. Plasmas 13, 112301 (2006).
http://dx.doi.org/10.1063/1.2363349
29.
29. A. P. L. Newton and E.-J. Kim, Phys. Plasmas 14, 122306 (2007).
http://dx.doi.org/10.1063/1.2821246
30.
30. P. W. Terry and R. Gatto, Phys. Plasmas 13, 062309 (2006).
http://dx.doi.org/10.1063/1.2212403
31.
31. G. M. Staebler, R. E. Waltz, J. Candy, and J. E. Kinsey, Phys. Rev. Lett. 110, 055003, (2013).
http://dx.doi.org/10.1103/PhysRevLett.110.055003
32.
32. B. Friedman, T. A. Carter, M. V. Umansky, D. Schaffner, and B. Dudson, Phys. Plasmas 19, 102307 (2012).
http://dx.doi.org/10.1063/1.4759010
33.
33. M. Umansky et al., Phys. Plasmas 18, 055709 (2011).
http://dx.doi.org/10.1063/1.3567033
34.
34. P. Popovich, M. V. Umansky, T. A. Carter, and B. Friedman, Phys. Plasmas 17, 122312 (2010).
http://dx.doi.org/10.1063/1.3527987
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Figures

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FIG. 1.

(a) Diagram of the LAPD device showing relative location of the annular limiter and basic biasing setup. (b) Velocity profiles using plasma potential from swept measurements. (c) Flow at the limiter edge (black, triangles) and mean shearing rate, averaged over (red, circles).

Image of FIG. 2.

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FIG. 2.

(a) Single shot (not averaged) time series of density fluctuations from a Langmuir probe at 29 cm. The black curve shows the trace for the minimum shearing rate state while the red is for a high flow shear state. The 3.2 ms shown is the temporal averaging region. (b) Time series for radial velocity fluctuations (mean subtracted) taken using two vertically spaced floating potential probe tips also at 29 cm.

Image of FIG. 3.

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FIG. 3.

Shot-averaged profiles of (a) density fluctuations, (b) radial velocity fluctuations, (c) particle flux, and (d) shearing rate normalized to . The limiter edge is indicated by the purple dotted line at 26 cm. The spatial averaging region is indicated by the dashed lines between 27 and 31 cm. The three curves for each of the first three plots show the suppression of the quantity with increase shearing rate inside the spatial averaging region. The averaging region avoids direct influence from the coherent mode localized at the limiter edge.

Image of FIG. 4.

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FIG. 4.

Scaling of (a) density fluctuation amplitude, (b) radial velocity fluctuation amplitude, and (c) density-radial velocity crossphase. Density and velocity fluctuations are each normalized to the value measured at minimum shear. The green curves correspond to fits of the weak shear regime for density fluctuations and crossphase, while radial velocity fluctuations are fit to in the weak shear regime. The blue curves all correspond to fits for each of the three plots. The last three points in each plot are not included in the fits due to potential influence of the coherent mode at high shearing rate.

Image of FIG. 5.

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FIG. 5.

Scaling of (a) radial particle flux and (b) diffusion coefficient each normalized to the value at minimum shear, and . The green curves correspond to fits of the weak shear regime with for flux and for D. The blue curves correspond to fits with for flux and for D. The last three points in each plot are not included in the fits do to potential influence of the coherent mode at high shearing rate.

Image of FIG. 6.

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FIG. 6.

Normalized correlation functions for (a) unbiased, IDD flow state, (b) no shear state, and (c) high bias, high EDD flow state where the black curve represents a decrease of 0.5 from peak. (Color scale indicates normalized correlation for all three biases.) (d) Radial correlation length normalized to maximum correlation length (5.5 cm) versus normalized shearing rate with M2 fits for weak (green) and strong (blue) shear. (e) Ratio of radial correlation length to density gradient scale length.

Image of FIG. 7.

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FIG. 7.

Ratio of velocity gradient length scale to density gradient length scale versus normalized shearing rate in the radial region of 27 to 31 cm.

Image of FIG. 8.

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FIG. 8.

Log-log plot of (a-b) density fluctuation amplitude and (c-d)particle flux versus shearing rate. Weak shear fits, (a) and (c), are shown with the solid red lines and a theoretical prediction—dashed line—of is included for comparison of slope (line is manually offset). Strong shear fits, (b) and (d), are shown with the solid blue lines and theoretical predictions are indicated with the dashed lines. The last three points in each plot are not included in the fits do to potential influence of the coherent mode at high shearing rate.

Image of FIG. 9.

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FIG. 9.

Fits over a shear range spanning both weak and strong regimes for (a) density fluctuation amplitude, (b) particle flux, (c) diffusivity, and (d) crossphase. Red lines correspond to model while the blue curves correspond to the model.

Tables

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Table I.

Power-law fits for with shear for frequencies in 350 Hz to 100 kHz. Model form is the particular model used in the fit, with C a constant and ν resulting best-fit exponent.

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Table II.

Power-law fits for scaling with shear for frequencies in 350 Hz to 100 kHz.

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Table III.

Power-law fits for scaling with shear for frequencies in 350 Hz to 100 kHz.

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Table IV.

Power-law fits for scaling with shear for frequencies in 350 Hz to 100 kHz.

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Table V.

Power-law fits for scaling with shear for frequencies in 350 Hz to 100 kHz.

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Table VI.

Power-law fits for scaling with shear for frequencies in 350 Hz to 100 kHz.

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Table VII.

Power law fits for all quantities over a range that spans both weak and strong shear. The smallest two shearing rate values are excluded to improve the fitting routine and the three highest shearing rate values are excluded to avoid effects of the coherent mode.

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/content/aip/journal/pop/20/5/10.1063/1.4804637
2013-05-15
2014-04-16

Abstract

Continuous control over azimuthal flow and shear in the edge of the Large Plasma Device (LAPD) [W. Gekelman , Rev. Sci. Instr. , 2875 (1991)] has been achieved using a biasable limiter. This flow control has allowed a careful study of the effect of flow shear on pressure-gradient-driven turbulence and particle transport in LAPD. The combination of externally controllable shear in a turbulent plasma along with the detailed spatial diagnostic capabilities on LAPD makes the experiment a useful testbed for validation of shear suppression models. Motivated by these models, power-law fits are made to the density and radial velocity fluctuation amplitudes, particle flux, density-potential crossphase, and radial correlation length. The data show a break in the trend of these quantities when the shearing rate ( ) is comparable to the turbulent decorrelation rate ( ). No one model captures the trends in the all turbulent quantities for all values of the shearing rate, but some models successfully match the trend in either the weak ( ) or strong ( ) shear limits.

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Scitation: Turbulence and transport suppression scaling with flow shear on the Large Plasma Devicea)
http://aip.metastore.ingenta.com/content/aip/journal/pop/20/5/10.1063/1.4804637
10.1063/1.4804637
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