OPERATIONAL SCENARIO of
KTM
Dokuka V.N., Khayrutdinov R.R.
TRINITI, Russia
Outline
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Goal of the work
The DINA code capabilities
Formulation of the problem
Examples of simulations
Conclusions
Future work
Goal of the work
• Modeling of different discharge
scenarios for KTM tokamak
• Optimization of Ramp-up processes
• Development of PF currents
waveforms for ramp-up and flat-top
and shut-down cases
• Study OH and ICRF heating regimes
with different heat conductivity
scaling-laws
• Plasma vertical position stabilization
control
• Disruptions simulation
• X-point position control
Equilibrium and transport modeling
code DINA
DINA is Free Boundary Resistive MHD and
Transport-Modeling Plasma Simulation Code
The following problems for plasma can be solved:
• Plasma position and shape control;
• Current ramp up and shut down simulations;
• Scenarios of heating, fuelling, burn and noninductive current drive;
• Disruption and VDE simulations (time evolution,
halo currents and run away electron effects);
• Plasma equilibrium reconstruction;
• Simulation of experiments in fitting mode using
experimental magnetic and PF measurements
• Modeling of plasma initiation and dynamic null
formation.
DINA code applications
• DINA code has been benchmarked with PET,
ASTRA and TSC codes. Equilibrium part was
verified to the EFIT code
• Control, shaping, equilibrium evolution have
been validated against DIII-D, TCV and JT-60
experimental data
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Disruptions have been studied at DIII-D, JT60, Asdex-U and COMPASS-D devices
• Breakdown study at NSTX and plasma ramp-up at
JT-60 and DIII-D
• Discharge simulations at FTU, GLOBUS and
T11 tokamaks
• Selection of plasma parameters for ITER,
IGNITOR, KTM and KSTAR projects
• Modeling of plasma shape and position
control for MAST, TCV and DIII-D
Theoretical and numerical analysis of
plasma-physical processes at KTM
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Breakdown and plasma initiation
Ramp-up
Flat-top
Plasma Vertical Stability
Disruptions
Shot down
Scheme of discharge scenario at KTM
Bt = 1 T
IP = 0.75 MA
Paux = 5 MW
Plasma current
flat-top
Vacuum
creation, gas
puff
Toroidal magnetic
field creation
Plasma current
initiation
Plasma current
ramp-up
Plasma current
shut-down
Auxiliary heating
The previous KTM
scenario (2)
Plasma current current density, boundary and
equilibrium during ramp-up
Ramp-up (1)
Results of plasma initiation calculation
are inputs for ramp-up simulation ( values
of PF coil and vessel and total plasma
currents, plasma current density)
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• Set of snapshot calculations are used to
choose waveforms for PF coil and plasma
current and for plasma boundary ;
• Transition from limited to X-point
plasma is carefully modeled;
• Optimization of Volt-second
consumption of inductor-solenoid is
carried out;
• Ramp-up time ( speed of ramp-up) is
optimized to avoid “skin currents” at
plasma boundary;
• Pf coil currents and density waveforms
are carefully programmed to avoid plasma
instability and runaway current
Techniques used for creation PF
scenario
• Dina calculates plasma equilibrium with
programmed PF currents
• Programmed parameters are plasma
density, plasma current, auxiliary heating
power
• To simulate plasma evolution one must use
a controller. Today it is absent
• We had to apply DINA means for
controlling plasma current by using CS
current, and to control R-Z position by
using PF3 and HFC currents respectively
• How to create PF programmed set:
• The initial PF data was obtained in the end
of stage of plasma initiation
• At first the plasma configurations at the
end of ramp up stage and for flat top are
calculated
Programmed inputs for DINA
n(t)
P(t)
Ip(t)
PF(t)
PF(t)
DINA
Techniques used for creation PF
scenario (continue)
• Having used such a programmed PF
currents, we find out that plasma
configuration becomes wrong from some
moment. To stop simulation at this
moment! To write required information for
fulfilling the next step
• To calculate a static desired plasma
configuration by taking into account
information concerning plasma current
profile and vacuum vessel filaments
currents obtained at some previous
moment
• A new PF currents should be included in
PF programmed set
• To carry out simulation up to this moment.
• To repeat procedure of improving PF
current data for achieving good agreement
• To continue simulation further
A set of initial snapshot calculations
time= 9 ms
time= 499 ms
time= 279 ms
time= 3999 ms
An initial set of programmed PF
currents
time, ms
0.
280.
500.
4500.
Ipf1, kA
4.50
0.94
0.04
-5.54
Ipf2, kA
11.21
0.97
2.42
-1.35
Ipf3, kA
0.48
-3.29
-3.91
-4.27
Ipf4, kA
6.19
23.39
18.86
10.42
Ipf5, kA
-7.94
-12.86
-8.46
-9.42
Ipf6, kA
0.01
-3.25
-3.97
-4.28
ICS, kA
24.48
-5.10
-5.62
-26.21
IHFC, kAt
-91.04
5.61
1.24
1.19
Ramp –up (initial equilibrium)
Plasma equilibrium during ramp-up
Equilibrium at the end of ramp-up
Plasma equilibrium during ramp-up
Ramp –up (profiles)
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Plasma current density profiles
Safety factor profiles
Electron temperature profiles
Bootstrap current profiles
Plasma parameters on the stage of
ramp up
Time
3 ms
280 ms
Plasma current, Ip, kA
50.0
751.6
Poloidal beta, p
0.54
0.14
Minor radius, a, cm
20.1
44.9
Major radius, R, cm
115.7
89.5
Vacuum vessel current Ivv, kA
50.1
31.2
Averaged electron density, ne14
0.11
0.52
Elongation, 
0.95
1.76
Averaged electron temperature, Te, eV
160.
267.
Averaged ion temperature, Ti, eV
150.
259.
Safety factor qaxis
1.29
0.99
Safety factor qbound
2.94
3.93
Normalized beta, N
0.69
0.52
Confinement time, E , ms
5.31
37.50
Resistive loop voltage, Ures, V
1.34
1.48
Bootstrap current, Ibs , kA
4.04
32.30
Ohmic heating, P , MW
0.066
1.109
Auxiliary heating, PICRH , MW
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R-coordinate of X-point, cm
137.50
77.53
Z-coordinate of X-point,cm
30.50
-58.60
Flat-top
• Set of snapshot calculations are used to
choose waveforms for PF coil and plasma
current and for plasma boundary ;
• Optimization of Volt-second consumption of
inductor-solenoid is carried out for Ohmic and
Auxiliary Heating scenarios
• Different scaling-laws for heat conductivity (
Neo-Alcator, T-11, ITER-98py ) are used
• Different profiles of auxiliary heating
deposition can be applied
• Optimization of scenario to avoid MHD
instabilities
• X-point swiping to minimize thermal load at
divertor
Plasma parameters on flat top
Time
280+ ms 4500m
s
Plasma current, Ip, kA
751.6
752.2
Poloidal beta, p
0.14
0.60
Minor radius, a, cm
44.9
44.6
Major radius, R, cm
89.5
89.9
Vacuum vessel current Ivv, kA
31.2
2.1
Averaged electron density, ne14
0.52
0.53
Elongation, 
1.76
1.76
Averaged electron temperature, Te, eV
267.
1221.
Averaged ion temperature, Ti, eV
259.
1006.
Safety factor qaxis
0.99
0.93
Safety factor qbound
3.93
3.99
Normalized beta, N
0.52
2.32
Confinement time, E , ms
37.50
29.46
Resistive loop voltage, Ures, V
1.48
0.18
Bootstrap current, Ibs , kA
32.30
207.14
Ohmic heating, P , MW
1.109
0.132
Auxiliary heating, PICRH , MW
5.0
5.0
R-coordinate of X-point, cm
77.53
73.26
Z-coordinate of X-point,cm
-58.60
-60.00
PF currents scenario
(PF1-PF6, CS, HFC)
Flat-top (typical configuration)
Plasma equilibrium during flat-top
Evolution of plasma parameters 1
1.
2.
3.
4.
Plasma current
Poloidal beta
Minor radius
Horizontal magnetic axis
Evolution of plasma parameters 2
1.
2.
3.
4.
Averaged electron density
Elongation
Internal inductance
Vacuum vessel current
Evolution of plasma parameters 3
1.
2.
3.
4.
Averaged ion temperature
Safety factor on magnetic axis
Safety factor on the plasma boundary
Averaged electron temperature
Evolution of plasma parameters 4
1.
2.
3.
4.
Electron density in the plasma center
Global confinement time
Major plasma radius
Resistive loop voltage
Evolution of plasma parameters 5
1.
2.
3.
4.
Vertical position of magnetic axis
Bootstrap current
beta
Normalized beta
Evolution of plasma parameters 6
1.
2.
3.
4.
Ion temperature on magnetic axis
Auxiliary heating (ICRH)
Electron temperature on magnetic axis
Resistive loop Volt-seconds
Evolution of plasma parameters 7
1.
2.
3.
4.
Total Volt-seconds
Plasma Volt-seconds
External Volt-seconds
Ion confinement time
Evolution of plasma parameters 8
1.
2.
3.
4.
Ion confinement time
Volt-seconds of PF (without CS)
Volt-seconds of CS
Ohmic heating power
Evolution of plasma parameters 9
1.
2.
3.
4.
Minor radius (95%)
Upper elongation (95%)
Down elongation (95%)
Elongation (95%)
Evolution of plasma parameters 10
1.
2.
3.
4.
Upper triangularity (95%)
Down triangularity (95%)
Triangularity (95%)
Horizontal position of magnetic axis
Evolution of plasma parameters 11
1.
2.
3.
4.
Z-coordinate of X-point
Current in upper passive plate
Current in lower passive plate
R-coordinate of X-point
Flat-top (profiles - 1)
• Plasma current density profiles
• Safety factor profiles
• Electron temperature profiles
• Bootstrap current profiles
Flat-top (profiles –2 )
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Plasma current density profiles
Safety factor profiles
Electron temperature profiles
Bootstrap current profiles
Flat-top (profiles –3)
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Plasma current density profiles
Safety factor profiles
Electron temperature profiles
Bootstrap current profiles
Volt-seconds balance
Conclusions
• The creation of scenario for KTM
including ramp-up and flat-top stages have
been carried out
• Optimization of ramp-up process helped to
save Volt-seconds consumptions from PF
system
• Simulations of Ohmic and ICRF heating
scenario show a possibility to achieve
stable plasma parameters
Future work
• Additional work on development of
integrated plasma shape and position
controllers is required
• Integration of 2D-breakdown and DINA
codes to do “all” scenario simulation (
breakdown-shutdown) in one step is
desirable
• A more accurate wave Altoke-e code,
consistent with DINA, is planned to use
for modeling ICRF heating
Simulink model for R-Z control of
KTM
The results of simulation of R-Z
control for KTM