Published December 2000 | Version v1
Journal article Metadata-only

Experimental studies on NBI and ICRF heated plasmas in the large helical device

Creators

  • 1. National Institute for Fusion Science, Oroshi-cho 322-6, Toki, Gifu-ken, 509-5292 (Japan)
  • 2. Graduate University for Advanced Studies, Hayama, 240-0193 (Japan)
  • 3. Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8603 (Japan)

Description

In the Large Helical Device (LHD), upgrading of the key hardware system since the last EPS conference has led to (1) higher Te (Te(0) = 4.4 keV at 5.3x1018 m-3 and Pabs = 1.8 MW); (2) higher confinement (τE = 0.3 s, Te(0) 1.1 keV at 6.5x1019 m-3 and Pabs = 2.0 MW); (3) higher stored energy Wpdia = 880 kJ; and (4) the highest β value in helical devices (2.4% at B = 1.3 T). The energy confinement was systematically higher than that predicted by the International Stellarator Scaling 95 up to a factor of 1.6. Ion cyclotron range of frequencies (ICRF) power up to 1.3 MW was reliably injected into the plasma without significant impurity contamination and a plasma with stored energy of 200 kJ was sustained for 5 s by ICRF alone. Long pulse discharges greater than 1 min in duration have been successfully achieved with ICRF power alone and with neutral beam injection (NBI) power alone. With NBI heating an 80 s discharge was achieved with a heating power of 0.5 MW at 2.75 T. The electron density was maintained at around 1.6x1019 m-3 by controlled gas puffing. The central electron and ion temperatures were kept around 1.5 keV. With ICRF heating, a similar long pulse discharge was achieved for 68 s with a heating power of 0.85 MW. The sustained plasma parameters are: Wp ∼ 110 kJ, Te(0) ∼ Ti(0) = 2.0 keV and = 1.0x1019 m-3. During these discharges, no increase in radiation power has been observed. (author)

Availability note (English)

Available online at the Web site for the journal Plasma Physics and Controlled Fusion (ISSN 1361-6587) http://www.iop.org/

Additional details

Identifiers

URL
http://www.iop.org/;

Publishing Information

Journal Title
Plasma Physics and Controlled Fusion
Journal Volume
42
Journal Issue
12B
Journal Page Range
p. 51-60
ISSN
0741-3335

Conference

Title
27. European Physical Society (EPS) conference on controlled fusion and plasma physics
Dates
12-16 Jun 2000
Place
Budapest (Hungary)

INIS

Country of Publication
United Kingdom
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
32002909
Subject category
S70: PLASMA PHYSICS AND FUSION TECHNOLOGY;
Resource subtype / Literary indicator
Conference
Descriptors DEI
BEAM INJECTION HEATING; CONFINEMENT TIME; ELECTRON TEMPERATURE; ICR HEATING; ION TEMPERATURE; LHD DEVICE; PLASMA CONFINEMENT; PLASMA RADIAL PROFILES; STORED ENERGY; TIME DEPENDENCE
Descriptors DEC
CLOSED PLASMA DEVICES; CONFINEMENT; ENERGY; HEATING; HIGH-FREQUENCY HEATING; PHYSICAL PROPERTIES; PLASMA HEATING; SUPERCONDUCTING DEVICES; THERMODYNAMIC PROPERTIES; THERMONUCLEAR DEVICES