Study of electron temperature profile evolution during L-H transition with measurement of electron cyclotron emission on DIII-D
- Southwest Inst. of Physics, Sichuan, SC (China)
- General Atomics, San Diego, CA (United States)
- Oak Ridge National Lab., TN (United States)
- Inst. of Plasma Physics, Hefei, AH (China)
The L-H transition has been intensively investigated since it was discovered in the ASDEX tokamak in 1982. Considerable experimental evidence shows that the formation of the transport barrier at the plasma edge, during which the edge density and temperature gradients suddenly increase, is a common feature in the L-H transition discharge in all devices. Formation of the transport barrier is indicated by a sharp reduction in the D{alpha} radiation at the periphery of the plasma despite a simultaneous increase in the plasma density. A new heterodyne electron cyclotron emission radiometer, which had been built for the ATF device at the Oak Ridge National Laboratory, has been installed on DIII-D. The instrument features 32 channels with high temporal and spatial resolution and covers the outer half of DIII-D plasma at full magnetic field. Initial measurements with the instrument at the time of the L-H transition show that there is no T{sub e}, precursor to the transition and this is further supported by observations during dithering L-H transition where the transport barrier is immediately destroyed when the plasma briefly returns to the L-mode during process of the transition. Other applications of the new instrument have included T{sub e}, profile measurements during edge localized modes and during Ohmic and beam-heated sawteeth, which highlight the magnetic reconnection process. The instrument will be described and some of these results win be presented.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114
- OSTI ID:
- 106481
- Report Number(s):
- GA-A22038; CONF-950112-5; ON: DE95017845; TRN: 95:022022
- Resource Relation:
- Conference: 9. joint workshop on electron cyclotron emission and electron cyclotron resonance heating, Borrego Springs, CA (United States), 23-26 Jan 1995; Other Information: PBD: Jun 1995
- Country of Publication:
- United States
- Language:
- English
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