Confinement Studies In TFTR

M. Murakamia, V. Arunasalam, J.D. Bella, M.G. Bell, M. Bitter, W.R. Blanchard, F. Boody, D. Boydb, N. Bretz, C.E. Busha, J.D. Callenc, J.L. Cecchi, R.J. Colchina, J. Coonrod, S.L. Davis, D. Dimock, H.F. Dylla, P.C. Efthimion, L.C. Emersona, A.C. Englanda, H.P. Eubank, R. Fonck, E. Fredrickson, H.P. Furth, L.R. Grisham, S. von Goeler, R.J. Goldston, B. Grek, D.J. Grove, R.J. Hawryluk, H. Hendeld, K.W. Hill, R. Hulse, D. Johnson, L.C. Johnson, R. Kaita, J. Kamperschroer, S.M. Kaye, M. Kikuchie, S. Kilpatrick, H. Kugel, P.H. LaMarche, R. Little, C.H. Maa, D. Manos, D. Mansfield, M. McCarthy, R.T. McCann, D.C. McCune, K. McGuire, D.M. Meade, S.S. Medley, D.R. Mikkelsen, D. Mueller, E. Nieschmidtf, D.K. Owens, V.K. Parea, H. Park, B. Prichard, A. Ramsey, D.A. Rasmussena, A.L. Roquemore, P.H. Rutherford, N.R. Sauthoff, J. Schivell, J-L. Schwobg, S.D. Scott, S. Sesnic, M. Shimadae, J.E. Simpkinsa, J. Sinnis, F. Staufferb, B. Stratton, S. Suckewer, G.D. Tait, G. Taylor, F. Tenney, C.E. Thomasa, H.H. Towner, M. Ulrickson, R. Wieland, M. Williams, K-L. Wong, A. Wouters, H. Yamadah, S. Yoshikawa, K.M. Young, M.C Zarnstorff

Fusion Science and Technology | Volume 8 | Number 1 | July 1985 | Pages 657-663

Plasma Engineering | Proceedings of the Sixth Topical Meeting on the Technology of Fusion Energy (San Francisco, California, March 3-7, 1985) | doi.org/10.13182/FST85-A40115

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The paper describes the present (end of February 1985) status of the plasma confinement studies in the TFTR tokamak with emphasis on those with neutral beam injection (NBI). Recent improvements in the device capabilities have substantially extended operating parameters: B_T increased to 4.0 T, I_p to 2.0 MA, injection power (P_b) to 5 MW with H° or D° beams, to 5 × 10¹⁹ m⁻³ and Z_eff reduced to 1.4. With ohmic heating (OH) alone, the previously established scaling for gross energy confinement time (τ_E ∝ ) has been confirmed at higher I_p and B_T, and the maximum τ_E of 0.4 sec has been achieved. With NBI at P_b, substantially (by factor > 2) higher than P_OH, excellent power and particle accountability have been established. This suggests that the less-than-expected increase in stored energy with NBI is not due to problems of power delivery, but due to problems of confinement deterioration. τ_E is observed to scale approximately as I_p P_b^−0.5 (independent of ), consistent with previous L-mode scalings. With NBI we have achieved the maximum τ_E of 0.2 s and the maximum T_i (o) of 4.4 keV in the normal operating regime, and even higher T_i(o) in the energetic-ion regime with low-n_e and low I_p operation.