JET multi-pellet injection experiments

Conference · Fri Jan 01 00:00:00 EST 1988

OSTI ID:6824898

Kupschus, P; Bartlett, D V; Behringer, K; Campbell, D J; Cheetham, A; Cordey, J G; Corti, S; Gadeberg, M; Gondhalekar, A; Gottardi, N A; Jarvis, O N; Morgan, P; O'Rourke, J; Sadler, G; Snipes, J; Stubberfield, D; Taroni, A; Tubbing, B; Von Hellermann, M ^[1]; Baylor, L R ; Houlberg, W A; Jernigan, T C; Milora, S L ^[2]; Galvao, R

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1. JET Joint Undertaking, Abingdon (UK)
2. Oak Ridge National Lab., TN (USA)

The multiple injection of deuterium pellets into JET plasmas under various scenarios for limiter and X-point discharges with currents up to 5 MA with pure ohmic, neutral beam and RF heating has been undertaken in a collaborative effort between JET and an USDOE team under the umbrella of the EURATOM-USDOE (US Department of Energy) Fusion Agreement on Pellet Injection using an ORNL built 3-barrel, repetitive multi-pellet launcher. The best plasma performance with pellet injection and additional heating so far has been obtained by injecting early into 3 MA, 3.1 T pulses while centrally depositing the pellet mass, with N{sub eo} initially well in excess of 10{sup 20} m{sup {minus}3}. Subsequent central heating of this dense and clean core by ion cyclotron resonance heating (ICRH) with H and {sup 3}He minorities in the 10 MW range yields T{sub eo} up to 12 keV and T{sub io} up to more than 10 keV, while n{sub eo} is decreasing (within up to 1.5s) decaying to 0.6 {times} 10{sup 20} m{sup {minus}3}, suggesting an enhanced central energy confinement in limiter discharges with only modestly improved global L-mode confinement. In this plasma core electron pressures of more than 1 bar with gradients in the order of 4 bar*m{sup {minus}1} have been reached with the total pressure approaching ballooning stability limits. The resulting total neutron rate from D-D reactions of up to 4.5*10{sup 15} s{sup {minus}1} so far increases strongly with RF power and can exceed that of similar non-enhanced shots by factors of 3 to 5. n{sub D}(O)*T{sub i}(O)*{tau}{sub E}(a) products in the range of 1 to 2*10{sup 20} m{sup {minus}3} keVs are obtained but combined power with neutral beams (up to 28 MW total), generally degrades the performance though leading to higher neutron rates of up to 7*10{sup 15} s{sup {minus}1}. 10 refs., 8 figs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6824898
• Report Number(s): CONF-8810231-10; ON: DE90011638; TRN: 90-027008
• Resource Relation: Conference: IAEA technical committee meeting on pellet injection and toroidal confinement, Gut Ising (Germany, F.R.), 24-26 Oct 1988
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
JET TOKAMAK
PELLET INJECTION
BALLOONING INSTABILITY
DEUTERIUM
ICR HEATING
LIMITERS
NEUTRONS
PLASMA CONFINEMENT
BARYONS
CONFINEMENT
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HEATING
HIGH-FREQUENCY HEATING
HYDROGEN ISOTOPES
INSTABILITY
ISOTOPES
LIGHT NUCLEI
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
PLASMA HEATING
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
STABLE ISOTOPES
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production
700205 - Fusion Power Plant Technology- Fuel
Heating
& Injection Systems