High–confinement radiative L–modes in ASDEX Upgrade

2021 ◽  
Author(s):  
Emiliano Fable ◽  
Arne Kallenbach ◽  
Rachael M McDermott ◽  
Matthias Bernert ◽  
Clemente Angioni

Abstract Experiments have been performed in the ASDEX Upgrade tokamak where plasmas are kept just below the H--mode threshold using feedback on the radiated power via seeded impurity. The resulting high--power L--modes show high confinement properties and no ELM activity due to the reduced pedestal height. The physics of these high--confinement L--modes is explored by means of integrated modeling to clarify the origin of the improved confinement.

1998 ◽  
Vol 59 (4) ◽  
pp. 587-610 ◽  
Author(s):  
P. E. VANDENPLAS ◽  
A. M. MESSIAEN ◽  
J. P. H. E. ONGENA ◽  
U. SAMM ◽  
B. UNTERBERG

From 1990, the boronized TEXTOR tokamak was characterized by an improved confinement (coined the ‘I mode’) at high power that was substantially better than the L mode, but densities had to be limited to n[bar]e0/nGR[lsim ]0.5–0.6, where nGR is the Greenwald density limit. With the injection of Ne, Si or Ar in order to increase the edge radiation and provided that γ=Prad/Ptot[greater, similar]0.5, PNBI-co/Ptot[greater, similar]0.25 and n[bar]e0/nGR[greater, similar]0.75, a further improved confinement called the radiative improved mode (RI mode) was discovered in 1993 on TEXTOR, a tokamak of intermediate size, and confirmed on TEXTOR-94. The radiated power fraction γ can reach 0.9, and the radiation is nearly isotropically distributed over the torus wall. The RI mode is characterized by its ability to obtain simultaneously and stationarily high densities and high confinement. It is linked to a substantial lowering of edge ne, Te and Ti, a reduction in particle transport and a peaking of the density profile. The RI-mode confinement scales on TEXTOR as τE= (n[bar]e0/nGR)τITERH93-P and values up to n[bar]e0/nGR≈1.2 are obtained. There is no detrimental concentration of the seeded impurity at the centre of the plasma. Results of three different interpretative and modelling approaches are in agreement with the improved confinement features; the preliminary indications are that ITG turbulence is strongly reduced. The Z mode observed on ISX-B has a clear resemblance to the RI mode. The very favourable features of the RI mode justify efforts in trying to establish it on larger machines to verify if the present scaling then holds.


2005 ◽  
Vol 48 (2) ◽  
pp. 208-217 ◽  
Author(s):  
Matthew Watson ◽  
Carl Byington ◽  
Douglas Edwards ◽  
Sanket Amin

2018 ◽  
Vol 49 (1) ◽  
pp. 47-62 ◽  
Author(s):  
Petra C. Schmid

Abstract. Power facilitates goal pursuit, but how does power affect the way people respond to conflict between their multiple goals? Our results showed that higher trait power was associated with reduced experience of conflict in scenarios describing multiple goals (Study 1) and between personal goals (Study 2). Moreover, manipulated low power increased individuals’ experience of goal conflict relative to high power and a control condition (Studies 3 and 4), with the consequence that they planned to invest less into the pursuit of their goals in the future. With its focus on multiple goals and individuals’ experiences during goal pursuit rather than objective performance, the present research uses new angles to examine power effects on goal pursuit.


2016 ◽  
Vol 101 (5) ◽  
pp. 721-730 ◽  
Author(s):  
Shirli Kopelman ◽  
Ashley E. Hardin ◽  
Christopher G. Myers ◽  
Leigh Plunkett Tost
Keyword(s):  

2014 ◽  
Author(s):  
Andrea C. Vial ◽  
Jaime L. Napier
Keyword(s):  

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