Electrostatic fluctuations and related transport in the edge and core plasma of the Keda Tokamak-5C

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.871757· OSTI ID:282801

Xu, Y; Wang, G; Zhai, K; Wang, C; Liu, W; Yu, C ^[1]

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1. Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, 230026, Peoples Republic of (China)

Using the swept double probe and triple probe technique, temperature, density and potential fluctuations have been measured in both the plasma edge and core of the Keda Tokamak-5C (KT-5C) [{ital World Survey of Activities in Controlled Fusion Research}, Nuclear Fusion Special Supplement (International Atomic Energy Agency, Vienna, 1991), p. 190]. The fluctuation-driven particle and energy fluxes were also estimated from the correlations of {l_angle}{tilde {ital n}}{sub {ital e{tilde E}}}{sub {theta}}{r_angle} and {l_angle}{tilde {ital T}}{sub {ital e{tilde E}}}{sub {theta}}{r_angle}. Evidence has been found that there exist substantial electron temperature fluctuations of {tilde {ital T}}{sub {ital e}}/{ital T}{sub {ital e}}{approx_equal}0.4{tilde {ital n}}{sub {ital e}}/{ital n}{sub {ital e}} in both regions. At the edge of KT-5C, many of the fluctuation features, such as the velocity shear stabilization of turbulence, the non-Boltzmann relation and the role of fluctuations in the edge confinement, are very similar to those obtained from other tokamaks. In the plasma interior, the fluctuations do obey the simple Boltzmann relationship and the profiles of the normalized fluctuating levels {tilde {ital n}}{sub {ital e}}/{ital n}{sub {ital e}} and {tilde {phi}}{sub {ital p}}/{ital T}{sub {ital e}} vary roughly as {tilde {ital n}}{sub {ital e}}/{ital n}{sub {ital e}}{proportional_to}{ital n}{sub {ital e}}{sup {minus}3/2} and {tilde {phi}}{sub {ital p}}/{ital T}{sub {ital e}}{proportional_to}{ital n}{sub {ital e}}{sup {minus}1/2}{ital T}{sub {ital e}}{sup {minus}1}, respectively. In addition, a spiky, radially intermittent structure in the particle and energy fluxes with large levels at the low-{ital q} resonances and lower levels in between was found. The experimental results provide some new evidence, particularly in the plasma core, for a better understanding of the basic mechanism of turbulence. {copyright} {ital 1996 American Institute of Physics.}

• OSTI ID: 282801
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 3 Vol. 3; ISSN 1070-664X; ISSN PHPAEN
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
FLUCTUATIONS
PLASMA DIAGNOSTICS
TEMPERATURE MEASUREMENT
TOKAMAK DEVICES
TURBULENCE