OPERATIONAL SCENARIO of KTM Dokuka V.N., Khayrutdinov R.R. TRINITI, Russia O u t l i n e O u t l i n e • Goal of the work • The DINA code capabilities • Formulation of the problem • Examples of simulations • Conclusions • Future work
Dec 13, 2015
OPERATIONAL SCENARIO of KTM
Dokuka V.N., Khayrutdinov R.R.
TRINITI, Russia
O u t l i n eO u t l i n e
• Goal of the work
• The DINA code capabilities
• Formulation of the problem
• Examples of simulations
• Conclusions
• Future 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 Plasma vertical position stabilization controlcontrol
• Disruptions simulationDisruptions simulation• X-point position controlX-point position control
Goal of the work
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 non-inductive 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
• Disruptions have been studied at DIII-D, JT-60, 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
• Breakdown and plasma initiationBreakdown and plasma initiation• Ramp-upRamp-up• Flat-topFlat-top• Plasma Vertical StabilityPlasma Vertical Stability• DisruptionsDisruptions• Shot downShot down
IP = 0.75 MA
Paux = 5 MW
Vacuum creation, gas
puff
Toroidal magnetic field creation
Plasma current initiation
Auxiliary heating
Bt = 1 T
Plasma current ramp-up
Plasma current flat-top
Plasma current shut-down
Scheme of discharge scenario at KTM
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)
• 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
• 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
Techniques used for creation PF scenario
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 mstime= 9 ms time= 279 mstime= 279 ms
time= 499 mstime= 499 ms time= 3999 mstime= 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, kAt -91.04 5.61 1.24 1.19
Ramp –up (profiles)
• 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 - -
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 4500ms
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
Evolution of plasma parameters 1
1. Plasma current2. Poloidal beta3. Minor radius4. Horizontal magnetic axis
Evolution of plasma parameters 2
1. Averaged electron density 2. Elongation3. Internal inductance4. Vacuum vessel current
Evolution of plasma parameters 3
1. Averaged ion temperature2. Safety factor on magnetic axis3. Safety factor on the plasma boundary4. Averaged electron temperature
Evolution of plasma parameters 4
1. Electron density in the plasma center2. Global confinement time3. Major plasma radius4. Resistive loop voltage
Evolution of plasma parameters 5
1. Vertical position of magnetic axis 2. Bootstrap current3. beta4. Normalized beta
Evolution of plasma parameters 6
1. Ion temperature on magnetic axis2. Auxiliary heating (ICRH) 3. Electron temperature on magnetic axis4. Resistive loop Volt-seconds
Evolution of plasma parameters 7
1. Total Volt-seconds2. Plasma Volt-seconds3. External Volt-seconds4. Ion confinement time
Evolution of plasma parameters 8
1. Ion confinement time2. Volt-seconds of PF (without CS)3. Volt-seconds of CS4. Ohmic heating power
Evolution of plasma parameters 9
1. Minor radius (95%)2. Upper elongation (95%)3. Down elongation (95%)4. Elongation (95%)
Evolution of plasma parameters 10
1. Upper triangularity (95%)2. Down triangularity (95%)3. Triangularity (95%)4. Horizontal position of magnetic axis
Evolution of plasma parameters 11
1. Z-coordinate of X-point2. Current in upper passive plate3. Current in lower passive plate4. 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 )
• Plasma current density profiles• Safety factor profiles• Electron temperature profiles• Bootstrap current profiles
Flat-top (profiles –3)
• Plasma current density profiles• Safety factor profiles• Electron temperature profiles• Bootstrap current profiles
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 workFuture 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