Development of a tokamak plasma optimized for stability and confinement

Conference · Wed Feb 01 04:00:00 EST 1995

OSTI ID:42487

Politzer, P A

Design of an economically attractive tokamak fusion reactor depends on producing steady-state plasma operation with simultaneous high energy density ({beta}) and high energy confinement ({tau}{sub E}); either of these, by itself, is insufficient. In operation of the DIII-D tokamak, both high confinement enhancement (H{equivalent_to} {tau}{sub E}/{tau}{sub ITER-89P} = 4) and high normalized {beta} ({beta}{sub N}{equivalent_to} {beta}/(I/aB) = 6%-m-T/MA) have been obtained. For the present, these conditions have been produced separately and in transient discharges. The DIII-D advanced tokamak development program is directed toward developing an understanding of the characteristics which lead to high stability and confinement, and to use that understanding to demonstrate stationary, high performance operation through active control of the plasma shape and profiles. The authors have identified some of the features of the operating modes in DIII-D that contribute to better performance. These are control of the plasma shape, control of both bulk plasma rotation and shear in the rotation and Er profiles, and particularly control of the toroidal current profiles. In order to guide their future experiments, they are developing optimized scenarios based on their anticipated plasma control capabilities, particularly using fast wave current drive (on-axis) and electron cyclotron current drive (off-axis). The most highly developed model is the second-stable core VH-mode, which has a reversed magnetic shear safety factor profile [q(O) = 3.9, q{sub min} = 2.6, and q{sub 95} = 6]. This model plasma uses profiles which the authors expect to be realizable. At {beta}{sub N} {>=} 6, it is stable to n=l kink modes and ideal ballooning modes, and is expected to reach H {>=} 3 with VH-mode-like confinement.

• Research Organization: General Atomics, San Diego, CA (United States); Oak Ridge National Lab., TN (United States); Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER51114; AC05-84OR21400; W-7405-ENG-48
• OSTI ID: 42487
• Report Number(s): GA-A--21926; CONF-941182--3; ON: DE95009609
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DOUBLET-3 DEVICE
OPERATION
OPTIMIZATION
PLASMA CONFINEMENT
STABILITY
TRANSIENTS