Speaker
Natalia A. Kirneva
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.1081.pdf
Confinement improvement triggered by the impurity injection in T-10 ECR
heated plasmas
N.A.Kirneva1,2, G.M.Asadulin1, V.M.Bajkov1, A.A.Borschegovskij1, M.M.Dremin1,
A.Ya.Kislov1, L.A.Kluchnikov1, V.A.Krupin1, S.V.Krylov1, A.V.Melnikov 1,2,
N.A.Mustafin1, A.R.Nemets1, Yu.D.Pavlov1, I.S.Pimenov1, G.N.Ploskirev1, D.V.Ryjakov1,
D.V.Sarychev1, D.S.Sergeev1, N.A.Solovev1, A.V.Sushkov1, V.M.Trukhin1, E.V.Trukhina1
1
National Research Center “Kurchatov Institute”, Moscow, Russia
2
National Research Nuclear University MEPhI, Moscow, Russia
Effect of the increase of the central electron temperature triggered by the Neon injection
in T-10 was observed for the first time in discharges with ECRH/ECCD (EC current drive in
co-direction to the total plasma current). Time evolution of the typical discharge is presented
in Figure 1 in comparison with the discharge without Ne puffing. Increase of the electron
temperature, plasma density and plasma energy content due to the impurity injection is clearly
seen. Experiments were carried out at moderate edge safety factor value qL~3. Toroidal
magnetic field was changed in the range of BT=2.42…2.18 T, which led to the shift of the EC
resonance position from the center to the high field side, ~a/2 (a- minor radius). The
phenomenon was observed in regime with slightly off-axis ECRH/ECCD, BT~2.25 T, when
the ECR power was absorbed in the vicinity of q=1 position and sawtooth oscillations were
suppressed. Destruction of the improved confinement is linked to the odd MHD mode
development (most possibly m=1 mode). Dependence of the value of the temperature gain on
the ECCD power has been investigated. Confinement improvement seems to be a result of
interplay between core current profile redistribution (with the increase of the gap between
resonance surfaces in vicinity of the q=1) and the increase of radiation losses from the edge
due to the Ne puffing.
3.5 Figure 1. Time evolution of the electron density
19 -3
a)
Te(0), keV ne, 10 m
3.0
(a), central electron temperature (b) and plasma
2.5
2.0 energy content (c) in similar T-10 discharges
1.5
2.5 b) with (red curves) and without (blue curves)
2.0 Neon puffing. Time and duration of Ne puffing
1.5
1.0 and ECRH/ECCD are presented in subplot (c).
c) Ne puffing
20
Wdia, kJ
15
ECRH/ECCD
10
700 750 800 850 900
time, ms
This work is supported by Rosatom and by RSF (project 14-22-00193).
