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——In
2005, more CFC were installed on HL
-2A
to protect divertor plates. The vessel wall
conditions are totally different with those in
passed years. In order to examine the actually
effects of more
CFC, the discharges have been performed in the
proper plasma parameter conditions. After several
days commissioning, obtained parameters are
toroidal fields 2.0 T, plasma current 200kA,
flat-top time of 500ms, duration time of 1000ms.
Reproducibility of discharge is quite well in 15
shots.
The
results obtained by the end of Sep., 2005 are
given in Figure.
——The
Ohmic positive and negative power supplies should
be precisely switched on in sequence. It has been
achieved successfully. Stable and reproducible
discharges were obtained using this toroidal field
control mode.The plasma current (Ip), ohmic
current (Ioh) and horizontal displacement (Dh)
from shots 3735-3739 are shown in the figures with
plasma duration time 2960ms, flat-top time 1800ms
and plasma
current 250kA.
——With
ohmic positive and negative power supplies working
together and with motor speed adjustment based on
frequency conversion for motors No.1 & 2,
plasma current of 400kA was obtained . The
parameters of SH03772 discharge are as following:
toroidal
magnetic fields BT = 2.65 T
duration
time TD =
1980 ms
In
the figure, the experimental plasma current (I_plas)
is shown as the red line, the plasma current
feedback control (ccIp) has been setup in advance
as the green line,
400kA line shown as the blue dotted line .
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