No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Validation of single-fluid and two-fluid magnetohydrodynamic models of the helicity injected torus spheromak experiment with the NIMROD code
4. T. R. Jarboe, W. T. Hamp, G. J. Marklin, B. A. Nelson, R. G. O'Neill, A. J. Redd, P. E. Sieck, R. J. Smith, and J. S. Wrobel, “Spheromak formation by steady inductive helicity injection,” Phys. Rev. Lett. 97, 115003 (2006).
5. T. R. Jarboe, A. R. Henins, I. Sherwood, C. W. Barnes, and H. W. Hoida, “Slow formation and sustainment of spheromaks by a coaxial magnetized plasma source,” Phys. Rev. Lett. 51, 39 (1983).
6. S. O. Knox, C. W. Barnes, G. J. Marklin, T. R. Jarboe, I. Henins, H. W. Hoida, and B. L. Wright, “Observations of spheromak equilibria which differ from the minimum-energy state and have internal kink distortions,” Phys. Rev. Lett. 56, 842 (1986).
8. A. J. Redd, B. A. Nelson, T. R. Jarboe, P. Gu, R. Raman, R. J. Smith, and K. J. McCollam, “Current drive experiments in the helicity injected torus (HIT-II),” Phys. Plasmas 9, 2006 (2002).
9. A. J. Redd, T. R. Jarboe, W. T. Hamp, B. A. Nelson, R. G. O'Neill, and R. J. Smith, “Flux amplification in helicity injected torus (HIT-II) coaxial helicity injection discharges,” Phys. Plasmas 15, 022506 (2008).
10. R. Raman, D. Mueller, T. R. Jarboe, B. A. Nelson, M. G. Bell, S. Gerhardt, B. LeBlanc, J. Menard, M. Ono, L. Roquemore, and V. Soukhanovski, “Experimental demonstration of tokamak inductive flux saving by transient coaxial helicity injection on national spherical torus experiment,” Phys. Plasmas 18, 092504 (2011).
11. K. J. McCollam, J. K. Anderson, A. P. Blair, D. Craig, D. J. Den Hartog, F. Ebrahimi, R. O'Connell, J. A. Reusch, J. S. Sarff, H. D. Stephens, D. R. Stone, D. L. Brower, B. H. Deng, and W. X. Ding, “Equilibrium evolution in oscillating-field current-drive experiments,” Phys. Plasmas 17, 082506 (2010).
13. T. R. Jarboe, C. Akcay, M. A. Chilenski, D. A. Ennis, C. J. Hansen, N. K. Hicks, R. Z. Aboul Hosn, A. C. Hossack, G. J. Marklin, B. A. Nelson, R. G. O'Neill, P. E. Sieck, R. J. Smith, B. S. Victor, J. S. Wrobel, and M. Nagata, “Recent results from the HIT-SI experiment,” Nucl. Fusion 51(6), 063029 (2011).
14. F. Ebrahimi, S. C. Prager, J. S. Sarff, and J. C. Wright, “The three-dimensional magnetohydrodynamics of ac helicity injection in the reversed field pinch,” Phys. Plasmas 10, 999 (2003).
15. E. B. Hooper, B. I. Cohen, H. S. McLean, R. D. Wood, C. A. Romero-Talamas, and C. R. Sovinec, “NIMROD resistive magnetohydrodynamic simulations of spheromak physics,” Phys. Plasmas 15, 032502 (2008).
16. B. I. Cohen, A. Romero-Talamas, D. D. Ryutov, E. B. Hooper, L. L. LoDestro, H. S. McLean, T. L. Stewart, and R. D. Wood, “The role of the n = 1 column mode in spheromak formation,” Phys. Plasmas 16, 042501 (2009).
17. R. D. Milroy, C. C. Kim, and C. R. Sovinec, “Extended magnetohydrodynamic simulations of field-reversed configurations formation and sustainment with rotating magnetic field current drive,” Phys. Plasmas 17, 062502 (2010).
18. J. B. O'Bryan, C. R. Sovinec, and T. M. Bird, “Simulation of current-filament dynamics and relaxation in the pegasus spherical tokamak,” Phys. Plasmas 19(8), 080701 (2012).
19. T. Gray, V. S. Lukin, M. R. Brown, and C. D. Cothran, “Three-dimensional reconnection and relaxation of merging spheromak plasmas,” Phys. Plasmas 17, 102106 (2010).
20. V. A. Izzo and T. R. Jarboe, “Three-dimensional magnetohydrodynamic simulations of the helicity injected torus with steady inductive drive,” Phys. Plasmas 12, 056109 (2005).
21. C. R. Sovinec, A. H. Glasser, T. A. Gianakon, D. C. Barnes, R. A. Nebel, S. E. Kruger, D. D. Schnack, S. J. Plimpton, A. Tarditi, and M. S. Chu, “Nonlinear magnetohydrodynamics simulation using high-order finite elements,” J. Comput. Phys. 195(1), 355–386 (2004).
22. C. R. Sovinec, D. D. Schnack, A. Y. Pankin, D. P. Brennan, H. Tian, D. C. Barnes, S. E. Kruger, E. D. Held, C. C. Kim, X. S. Li, D. K. Kaushik, S. C. Jardin, and NIMROD Team, “Nonlinear extended magnetohydrodynamics simulation using high-order finite elements,” J. Phys.: Conf. Ser. 16(1), 25 (2005).
23. C. R. Sovinec and J. R. King, “Analysis of a mixed semi-implicit/implicit algorithm for low-frequency two-fluid plasma modeling,” J. Comput. Phys. 229(16), 5803–5819 (2010).
24. D. A. Ennis, B. S. Victor, J. S. Wrobel, C. Akcay, T. R. Jarboe, G. J. Marklin, B. A. Nelson, and R. J. Smith, “New understandings and achievements from independent-injector drive experiments on HIT-SI,” Nucl. Fusion 50, 072001 (2010).
25. P. Sieck. Ph.D. Dissertation, University of Washington, Seattle, WA, 2006.
26. R. G. O'Neill, G. J. Marklin, T. R. Jarboe, C. Akcay, W. T. Hamp, B. A. Nelson, A. J. Redd, R. J. Smith, B. T. Stewart, J. S. Wrobel, and P. E. Sieck, “A fully relaxed helicity balance model for an inductively driven spheromak,” Phys. Plasmas 14, 112304 (2007).
27. B. S. Victor, T. R. Jarboe, A. C. Hossack, D. A. Ennis, B. A. Nelson, R. J. Smith, C. Akcay, C. J. Hansen, G. J. Marklin, N. K. Hicks, and J. S. Wrobel, “Evidence for separatrix formation and sustainment with steady inductive helicity injection,” Phys. Rev. Lett. 107, 165005 (2011).
28. T. R. Jarboe, B. S. Victor, B. A. Nelson, C. J. Hansen, C. Akcay, D. A. Ennis, N. K. Hicks, A. C. Hossack, G. J. Marklin, and R. J. Smith, “Imposed-dynamo current drive,” Nucl. Fusion 52(8), 083017 (2012).
29. U. Shumlak and T. R. Jarboe, “Stable high beta spheromak equilibria using concave flux conservers,” Phys. Plasmas 7, 2959 (2000).
30. P. M. Bellan, Fundamentals of Plasma Physics (Cambridge University Press, 2006).
31. V. S. Lukin, “Computational study of internal kink mode evolution and associated magnetic reconnection phenomena,” Ph.D. Dissertation (Princeton University, Princeton, NJ, 2008).
32. B. Srinivasan and U. Shumlak, “Analytical and computational study of the ideal full two-fluid plasma model and asymptotic approximations for Hall-magnetohydrodynamics,” Phys. Plasmas 18, 092113 (2011).
33. S. I. Braginskii, Transport Processes in a Plasma (Consultants Bureau, New York, 1965);
33. S. I. Braginskii, Rev. Plasma Phys. 1, 205 (1965).
36. H. Nowacki, M. I. G. Bloor, and B. Oleksiewicz, Computational Geometry for Ships (World Scientific Publishing, 1995).
38. C. A. Romero-Talamas, E. B. Hooper, R. Jayakumar, H. S. McLean, R. D. Wood, and J. M. Moller, “Measurements and phenomenological modeling of magnetic flux buildup in spheromak plasmas,” Phys. Plasmas 15, 042503 (2008).
39. J. S. Wrobel, C. J. Hansen, T. R. Jarboe, R. J. Smith, A. C. Hossack, B. A. Nelson, G. J. Marklin, D. A. Ennis, C. Akcay, and B. S. Victor, “Relaxation-time measurement via a time-dependent helicity balance model,” Phys. Plasmas 20, 012503 (2013).
40.Additional simulations (not included here) that model the long injector ramp-up period show a linear ramp in the Itor very similar to that exhibited by shots shown in Figure 8.
41.At the mid-plane, the poloidal and axial directions become aligned. Thus, Bθ = Bz.
42. B. S. Victor, T. R. Jarboe, A. C. Hossack, D. A. Ennis, B. A. Nelson, C. J. Hansen, and J. S. Wrobel, “Advances in steady inductive helicity injection for plasma startup and toroidal current drive,” IEEJ Trans. Fundamentals Mater. 132(7), 472–476 (2012).
43. T. D. Dudok de Wit, A. L. Pecquet, J. C. Vallet, and R. Lima, “The biorthogonal decomposition as a tool for investigating fluctuations in plasmas,” Phys. Plasmas 1, 3288 (1994).
44. N. Aubry, R. Guyonnet, and R. Lima, “Spatiotemporal analysis of complex signals: Theory and applications,” J. Stat. Phys. 64(3), 683–739 (1991).
45. E. T. Meier and U. Shumlak, “A general nonlinear fluid model for reacting plasma-neutral mixtures,” Phys. Plasmas 19, 072508 (2012).
Article metrics loading...
We present a comparison study of 3-D pressureless resistive MHD (rMHD) and 3-D presureless two-fluid MHD models of the Helicity Injected Torus with Steady Inductive helicity injection (HIT-SI). HIT-SI is a current drive experiment that uses two geometrically asymmetric helicity injectors to generate and sustain toroidal plasmas. The comparable size of the collisionless ion skin depth di to the resistive skin depth predicates the importance of the Hall term for HIT-SI. The simulations are run with NIMROD, an initial-value, 3-D extended MHD code. The modeled plasma density and temperature are assumed uniform and constant. The helicity injectors are modeled as oscillating normal magnetic and parallel electric field boundary conditions. The simulations use parameters that closely match those of the experiment. The simulation output is compared to the formation time, plasma current, and internal and surface magnetic fields. Results of the study indicate 2fl-MHD shows quantitative agreement with the experiment while rMHD only captures the qualitative features. The validity of each model is assessed based on how accurately it reproduces the global quantities as well as the temporal and spatial dependence of the measured magnetic fields. 2fl-MHD produces the current amplification and formation time demonstrated by HIT-SI with similar internal magnetic fields. rMHD underestimates and exhibits much a longer . Biorthogonal decomposition (BD), a powerful mathematical tool for reducing large data sets, is employed to quantify how well the simulations reproduce the measured surface magnetic fields without resorting to a probe-by-probe comparison. BD shows that 2fl-MHD captures the dominant surface magnetic structures and the temporal behavior of these features better than rMHD.
Full text loading...
Most read this month