JET neutron emission profiles and fast ion redistribution during sawtooth crashes
F B Marcus; J M Adams; A D Cheetham; S Conroy; W G F Core; O N Jarvis; M J Loughlin; M Olsson; G Sadler; P Smeulders; P Van Belle; N Watkins; F B Marcus; JET Joint Undertaking, Abingdon, UK; J M Adams; JET Joint Undertaking, Abingdon, UK; A D Cheetham; JET Joint Undertaking, Abingdon, UK; S Conroy; JET Joint Undertaking, Abingdon, UK; W G F Core; JET Joint Undertaking, Abingdon, UK; O N Jarvis; JET Joint Undertaking, Abingdon, UK; M J Loughlin; JET Joint Undertaking, Abingdon, UK; M Olsson; JET Joint Undertaking, Abingdon, UK; G Sadler; JET Joint Undertaking, Abingdon, UK; P Smeulders; JET Joint Undertaking, Abingdon, UK; P Van Belle; JET Joint Undertaking, Abingdon, UK; N Watkins; JET Joint Undertaking, Abingdon, UK
Журнал:
Plasma Physics and Controlled Fusion
Дата:
1991-04-01
Аннотация:
Measurements from the JET neutron profile monitor are analyzed tomographically to deduce the 2-D spatial distribution of neutron emissivity during NBI heating both before and after sawtooth crashes. In a discharge where the global neutron emission decreases slightly to 5/6 of the pre-crash rate of nearly 10<sup>16</sup> n s<sup>-1</sup>, the axial emissivity drops much more to only 1/6 of the pre-crash value. The sources of neutron emissivity are analyzed with an analytic Fokker-Planck formulation. The main change in neutron emissivity is due to fast ion redistribution during a sawtooth crash and a decrease in beam-beam-produced emissivity. The deduced fast ion redistribution is consistent with other observations of sawtooth behaviour in JET.
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