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Title: Physics of Compact Advanced Stellarators

Abstract

Compact optimized stellarators offer novel solutions for confining high-beta plasmas and developing magnetic confinement fusion. The 3-D plasma shape can be designed to enhance the MHD stability without feedback or nearby conducting structures and provide drift-orbit confinement similar to tokamaks. These configurations offer the possibility of combining the steady-state low-recirculating power, external control, and disruption resilience of previous stellarators with the low-aspect ratio, high beta-limit, and good confinement of advanced tokamaks. Quasi-axisymmetric equilibria have been developed for the proposed National Compact Stellarator Experiment (NCSX) with average aspect ratio 4-4.4 and average elongation of approximately 1.8. Even with bootstrap-current consistent profiles, they are passively stable to the ballooning, kink, vertical, Mercier, and neoclassical-tearing modes for beta > 4%, without the need for external feedback or conducting walls. The bootstrap current generates only 1/4 of the magnetic rotational transform at beta = 4% (the rest is from the coils), thus the equilibrium is much less nonlinear and is more controllable than similar advanced tokamaks. The enhanced stability is a result of ''reversed'' global shear, the spatial distribution of local shear, and the large fraction of externally generated transform. Transport simulations show adequate fast-ion confinement and thermal neoclassical transport similar to equivalent tokamaks.more » Modular coils have been designed which reproduce the physics properties, provide good flux surfaces, and allow flexible variation of the plasma shape to control the predicted MHD stability and transport properties.« less

Authors:
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Publication Date:
Research Org.:
Princeton Plasma Physics Lab., NJ (US)
Sponsoring Org.:
USDOE Office of Science (US)
OSTI Identifier:
787903
Report Number(s):
PPPL-3597
TRN: US0110753
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 14 Aug 2001
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASPECT RATIO; BOOTSTRAP CURRENT; HIGH-BETA PLASMA; MAGNETIC CONFINEMENT; ROTATIONAL TRANSFORM; SPATIAL DISTRIBUTION; STELLARATORS; PLASMA INSTABILITY; MAGNETOHYDRODYNAMICS

Citation Formats

Zarnstorff, M C, Berry, L A, Brooks, A, Fredrickson, E, Fu, G -Y, Hirshman, S, Hudson, S, Ku, L -P, Lazarus, E, Mikkelsen, D, Monticello, D, Neilson, G H, Pomphrey, N, Reiman, A, Spong, D, Strickler, D, Boozer, A, Cooper, W A, Goldston, R, Hatcher, R, Isaev, M, Kessel, C, Lewandowski, J, Lyon, J, Merkel, P, Mynick, H, Nelson, B E, Nuehrenberg, C, Redi, M, Reiersen, W, P. Rutherford, Sanchez, R, Schmidt, J, and White, R B. Physics of Compact Advanced Stellarators. United States: N. p., 2001. Web. doi:10.2172/787903.
Zarnstorff, M C, Berry, L A, Brooks, A, Fredrickson, E, Fu, G -Y, Hirshman, S, Hudson, S, Ku, L -P, Lazarus, E, Mikkelsen, D, Monticello, D, Neilson, G H, Pomphrey, N, Reiman, A, Spong, D, Strickler, D, Boozer, A, Cooper, W A, Goldston, R, Hatcher, R, Isaev, M, Kessel, C, Lewandowski, J, Lyon, J, Merkel, P, Mynick, H, Nelson, B E, Nuehrenberg, C, Redi, M, Reiersen, W, P. Rutherford, Sanchez, R, Schmidt, J, & White, R B. Physics of Compact Advanced Stellarators. United States. https://doi.org/10.2172/787903
Zarnstorff, M C, Berry, L A, Brooks, A, Fredrickson, E, Fu, G -Y, Hirshman, S, Hudson, S, Ku, L -P, Lazarus, E, Mikkelsen, D, Monticello, D, Neilson, G H, Pomphrey, N, Reiman, A, Spong, D, Strickler, D, Boozer, A, Cooper, W A, Goldston, R, Hatcher, R, Isaev, M, Kessel, C, Lewandowski, J, Lyon, J, Merkel, P, Mynick, H, Nelson, B E, Nuehrenberg, C, Redi, M, Reiersen, W, P. Rutherford, Sanchez, R, Schmidt, J, and White, R B. Tue . "Physics of Compact Advanced Stellarators". United States. https://doi.org/10.2172/787903. https://www.osti.gov/servlets/purl/787903.
@article{osti_787903,
title = {Physics of Compact Advanced Stellarators},
author = {Zarnstorff, M C and Berry, L A and Brooks, A and Fredrickson, E and Fu, G -Y and Hirshman, S and Hudson, S and Ku, L -P and Lazarus, E and Mikkelsen, D and Monticello, D and Neilson, G H and Pomphrey, N and Reiman, A and Spong, D and Strickler, D and Boozer, A and Cooper, W A and Goldston, R and Hatcher, R and Isaev, M and Kessel, C and Lewandowski, J and Lyon, J and Merkel, P and Mynick, H and Nelson, B E and Nuehrenberg, C and Redi, M and Reiersen, W and P. Rutherford and Sanchez, R and Schmidt, J and White, R B},
abstractNote = {Compact optimized stellarators offer novel solutions for confining high-beta plasmas and developing magnetic confinement fusion. The 3-D plasma shape can be designed to enhance the MHD stability without feedback or nearby conducting structures and provide drift-orbit confinement similar to tokamaks. These configurations offer the possibility of combining the steady-state low-recirculating power, external control, and disruption resilience of previous stellarators with the low-aspect ratio, high beta-limit, and good confinement of advanced tokamaks. Quasi-axisymmetric equilibria have been developed for the proposed National Compact Stellarator Experiment (NCSX) with average aspect ratio 4-4.4 and average elongation of approximately 1.8. Even with bootstrap-current consistent profiles, they are passively stable to the ballooning, kink, vertical, Mercier, and neoclassical-tearing modes for beta > 4%, without the need for external feedback or conducting walls. The bootstrap current generates only 1/4 of the magnetic rotational transform at beta = 4% (the rest is from the coils), thus the equilibrium is much less nonlinear and is more controllable than similar advanced tokamaks. The enhanced stability is a result of ''reversed'' global shear, the spatial distribution of local shear, and the large fraction of externally generated transform. Transport simulations show adequate fast-ion confinement and thermal neoclassical transport similar to equivalent tokamaks. Modular coils have been designed which reproduce the physics properties, provide good flux surfaces, and allow flexible variation of the plasma shape to control the predicted MHD stability and transport properties.},
doi = {10.2172/787903},
url = {https://www.osti.gov/biblio/787903}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2001},
month = {8}
}