1. magnetic confinement - ENEA - Fusione

1. MAGNETIC CONFINEMENT
31
1.2 FTU Facilities
1.8
1.4
1.1
0.7
a)
now complete (six gyrotrons and two coupling
structures). In this configuration, the system has
routinely operated with a total rf power of about 2.2
MW coupled to the plasma. The maximum electron
temperature achieved is about 12 keV. The system has
operated in synergy with the ECRH system, reaching,
in this case, an electron temperature of about 15 keV.
0.4
The new launchers
0.0
0.0
1.6
3.2
Fig.1.24 a
4.8
1 . 10-3
6.4 8.0
b)
At the end of 2001, the conventional multijunction
(MJ) grill was delivered to ENEA. The MJ with passive
waveguides (PAM) and the ancillary components
(dummy loads, short circuits, couplers, etc.) needed
for the complete rf test of both the launchers were still
under construction.
ECRH system
In 2001 the ECRH system operated with two gyrotrons
providing a total power of 800 kW at the plasma, at
nominal pulse length. To improve the power supply
system, a new voltage reference generator was
developed and successfully installed. The new system
is based on National Instruments hardware, has faster
control and a greater rejection of EM noise.
1.2.3 Diagnostics
Moments (Nm)
Moments (Nm)
Moments (Nm)
100
0
-100
40
0
-40
-100
-140
0.001
0.002
0.003
0.004
0.005
+ x x x x + + + + + + + + + +
x
+ + +
0.001 x 0.002 0.003
0.004
x x
x
x 0.005
x
x x x
x
x
x
x
x
x
Time (s)
0.006
Time (s)
0.006
40 x x
Time (s)
x
x
0 x x x + + + + + + + + + +
0.001 x 0.002 0.003 0.004 x x 0.006
x
x 0.005
-40
x x x
x
x x
-100
x
x
x
-140
x
x
x
x
+
x
+
x
+
Mx_1
My_1
Mz_1
Mx_2
My_2
Mz_2
Mx_3
My_3
Mz_3
Mx_4
My_4
Mz_4
Mx_5
My_5
Mz_5
Mx_6
My_6
Mz_6
Mx_7
My_7
Mz_7
Mx_8
My_8
Mz_8
Mx_9
My_9
Mz_9
Fig. 1.24 a) Current disruption at 1.6 MA. b) FEM used
for EM analysis of the toroidal limiter: tiles are
blanked out to expose the model. c) Radial (x),
vertical (y) and toroidal (z) torque components on
each tile, relative to tile centres, plotted vs. time for
the disruption event described in a).
c)
Development of active beam diagnostics
Measurements of the motional Stark effect (MSE) and
of charge-exchange spectroscopy will yield data on the
radial profiles of q, ion temperature and poloidal
velocity. Both measurements will use a fast-hydrogenatom
(40 keV) injector, which is being tested at the
Frascati laboratory.
The characteristics of the neutral beam injector, which
was previously used in the Canadian TdeV
laboratory, were measured in a reduced configuration,
i.e., by using a single-hole extraction grid rather than
the full 19-hole grid. A new bolometer, consisting of a
set of 12 Cu plates whose temperature was measured
by embedded thermocouples, was used to measure
the output power.
The beam parameters (gas feed, decelerating and
accelerating grid voltages and compressor coil
current) were optimised by maximising the output
power and emitted light. The optimum conditions in
this situation could not be reached because it was
impossible to operate both the source and the
neutraliser at the desired pressures. A directly heated
W filament that is simpler and easier to use has
substituted the original LaB6 cathode, which had to be
replaced frequently and had irregular behaviour. A