Active core profile and transport modification by application of ion Bernstein wave power in the Princeton Beta Experiment-Modification

Application of Ion Bernstein Wave Heating (IBWH) into the Princeton Beta Experiment‐Modification (PBX‐M) [Phys. Fluids B 2, 1271 (1990)] tokamak stabilizes sawtooth oscillations and generates peaked density profiles. A transport barrier, spatially correlated with the IBWH power deposition profile, is observed in the core of IBWH‐assisted neutral beam injection (NBI) discharges. A precursor to the fully developed barrier is seen in the soft x‐ray data during edge localized mode (ELM) activity. Sustained IBWH operation is conducive to a regime where the barrier supports large ∇ne, ∇Te, ∇νφ, and ∇Ti, delimiting the confinement zone. This regime is reminiscent of the H(high) mode, but with a confinement zone moved inward. The core region has better than H‐mode confinement while the peripheral region is L(low)‐mode‐like. The peaked profile enhances NBI core deposition and increases nuclear reactivity. An increase in central Ti results from χi reduction (compared to the H mode) and better beam penetration. Boot...

[1]  Paul W. Terry,et al.  Influence of sheared poloidal rotation on edge turbulence , 1990 .

[2]  J. D. Bell,et al.  Confinement in beam-heated plasmas: the effects of low-Z impurities , 1985 .

[3]  M. Porkolab,et al.  Radio frequency power in plasmas , 1994 .

[4]  K. Kawahata,et al.  High frequency ion Bernstein wave heating experiment in the JIPP T-IIU tokamak , 1992 .

[5]  Manickam,et al.  Improved plasma performance in tokamaks with negative magnetic shear. , 1994, Physical review letters.

[6]  T. Hellsten.  Plasma physics and controlled nuclear fusion research 1976 , 1977 .

[7]  R. E. Hatcher,et al.  Control of plasma shape and performance of the PBX‐M tokamak experiment in high‐βt /high‐βp regimes , 1990 .

[8]  C. Kessel,et al.  Heat transport in PBX-M high beta p plasmas , 1993 .

[9]  D. McCune,et al.  New techniques for calculating heat and particle source rates due to neutral beam injection in axisymmetric tokamaks , 1981 .

[10]  Winter,et al.  Improved plasma performance in TEXTOR with silicon coated surfaces. , 1993, Physical review letters.

[11]  M. Ono.  Ion Bernstein wave heating research , 1993 .

[12]  Tadashi Sekiguchi,et al.  Plasma Physics and Controlled Nuclear Fusion Research , 1987 .

[13]  A. Ware,et al.  Pinch Effect for Trapped Particles in a Tokamak , 1970 .

[14]  R. Bell,et al.  The PBX‐M Thomson scattering system , 1990 .

[15]  D. Swain,et al.  High-beta injection experiments on the ISX-B tokamak , 1981 .

[16]  J. Manickam,et al.  Experimental exploration of profile control in the Princeton Beta Experiment-Modified (PBX-M) tokamak , 1993 .

[17]  Bell,et al.  Effects of high-power ion Bernstein waves on a tokamak plasma. , 1988, Physical review letters.

[18]  J. Dunlap,et al.  Periods of enhanced transport during H-mode in PBX-M , 1994 .

[19]  Moody,et al.  Ion-Bernstein-wave heating and improved confinement in the Alcator C tokamak. , 1988, Physical review letters.