1J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Progress of the Integrated Plasma Control Working Group
ITER Organization
J A Snipes
2J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
ITPA Integrated Plasma Control Working Group Mandate: The ITPA IPCWG will determine the physics requirements of the actuators and diagnostics of the ITER Plasma Control System (PCS) to permit the PCS to carry out its control functions and to meet the goals of the ITER reference scenarios
Deliverable: Produce a document for input to the PCS design describing the physics requirements of the PCS actuators and diagnostics at the conceptual design level sufficient to show their feasibility to perform the PCS functions
Timescale: Preliminary report now, intermediate report at the April 2012 IOS meeting, followed by a final report at the October 2012 IOS meeting to be in
time for the PCS CDR in November 2012
Control Area Leaders: T Casper – Pressure Profile, D Humphreys – Actuator Sharing,
A Kallenbach – Divertor Heat Flux, R La Haye - NTM, T Luce – Temperature Profile, D Mazon – Current Density Profile,
R Pitts – First Wall Heat Flux, A Polevoi – Fueling and Impurity, J A Snipes – ELM, T Tala - Rotation, D Testa – Alfvén Eigenmode Control
3J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Integrated Plasma Control Working Group Activities
The ITPA IPCWG should provide physics input to quantify the ITER PCS requirements for actuators in time for the PCS CDR
This work should complement the work being done in the Plasma Control Group IPT and in the MHD ITPA Working Groups
• WG3: “Power requirements for ECRH & ICRF control of sawteeth”
• WG4 on “Diagnostic requirements for MHD stability control”
The IPCWG should assess the realistic feasibility of the PCS to carry out its control functions across a range of ITER scenarios
• early non-active scenarios in H/He at half and full current & field
• 15 MA, 5.3 T Q=10 inductive scenarios
• 10 – 13 MA, 5.3 T Q > 5 long pulse (1000 s) Hybrid scenarios
• 8 – 9 MA, 5.3 T Q~5 steady-state (3000 s) scenarios
4J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
What is Meant by Realistic Feasibility?
The IPCWG should take into account the actual constraints of the ITER diagnostics and actuators that will put real limits on the
control actions of the PCS
Through modeling and comparison with present experiments then determine how much those real diagnostic and actuator limitations are likely to affect the PCS control functions, such as
• NB RID thermal fatigue limits power modulation for burn control
• EC steering mirror full sweep takes 3 s + ~0.2 s to respond to PCS
The level of detail required depends on the impact a given constraint is likely to have and the amount of work required to assess it given the short timescale available before the CDR
For the CDR, only the control concept must be shown to be feasible not the detailed implementation nor the algorithms
5J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
MHD WG4 Already Did Much of the Diagnostics Task
The work was broken down into eight MHD stability or control method areas:• Stabilisation of the Vertical instability• Stabilisation of the Resistive Wall Mode (RWM) instability • Stabilisation of the Neoclassical Tearing Mode (NTM) instability• Stabilisation or modification of the Sawtooth instability• Stabilisation or modification of the Edge Localised Mode (ELM) instability• Control or modification of of the Alfvén Eigenmode (AE) instabilities• Control of the error fields leading to enhancement of instabilities• Control, prediction, avoidance or mitigation of plasma disruptive instability
Leaders, Contributors and Reviewers were nominated for each topicThe Leaders drove the process for each topic, with assistance from the ContributorsThe Reviewers reviewed the findings of the Leaders and ContributorsAn Excel spreadsheet template was used to summarise the quantifiable requirements and any unquantifiable requirements for each topic
6J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Example of MHD WG4 Diagnostic Requirements
Leader: A. Isayama (JA-JAEA)
Contributors:O. Sauter (EU-CRPP), R. La Haye (US-GA), M. Reich (EU-AUG), E. Westerhof (EU-FOM), S. Nowak (EU-Milano)
Reviewers: Y. Gribov (IO), H .Zohm (EU-AUG), R. Buttery (US-GA), V.D. Pustovitov (RF-KRC)
Stabilisation of the Neoclassical Tearing Mode (NTM) instability
7J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Integrated Plasma Control Working Group Progress
The IPCWG is assessing the physics requirements of the ITER PCS actuators in a similar set of spreadsheets for actuators
In addition, the IPCWG should assess diagnostic requirements in all other control areas outside MHD control as well as for
runaway electron control and mitigation
First draft spreadsheets have been produced in all of the control areas initially proposed
8J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Fuelling and Impurity Control – 1: PelletsArea: Fueling and Impurity ControlDescription: Actuator specifications required or supplementary to control plasma fueling and both injected and sputtered impuritiesLeader: A. Polevoi (IO)Contributors: S. Maruyama (IO), E. Veshchev(IO), A.Kukushkin(IO), E.C. Skinner (US), M. Beurskens (EU), B. Stratton (US)Reviewers: J. Snipes (IO)
ActuatorPlasma parameter controlled
Availability(conditions in which it is required)
Actuator output controlled
RangeHardware dynamic limits
Hardware response time
Target area /Response time
Affected area /Response time
Affected actuators /Response time
Affecting actuators
Pellet injection
Electron density, ne and tritium density nT
DT operation if puffing is not sufficient
Source of D and T,SDT
SDT < 111 Pam3/s(up to 90%T + 10%D)
2 injectorsPellet sizes:V=92/50/33/17 mm3Frequency: 4-16 HzVariation ~ factor of 2 in 3 s
70 ms(flight in tube for 300 m/s HFS pellet).
Core/penetration to center ~ 0.2 – 4 TauE [3]
SOL/Div~ 10 ms
ELM pacing,Gas puffing,Div control,ICRH,Pumping
/All~ 10 ms
ELM pacing,Gas puffing,Div control,Pumping
/ All~ 10 ms
Pellet injectionElectron density, ne and deuterium nD
DD,DT operation if puffing is not sufficient
Source of DSD < 100Pam3/s
2 injectorsPellet sizes:V=92/50/33/17 mm3Frequency: 4-16 HzVariation ~ factor of 2 in 3 s
70 ms(flight in tube for 300 m/s HFS pellet).
Core/penetration to center ~ 0.2 – 4 TauE [3]
SOL/Div~ 10 ms
ELM pacing,Gas puffing,Div control,ICRH,Pumping
/All~ 10 ms
ELM pacing,Gas puffing,Div control,Pumping
/ All~ 10 ms
Pellet injectionElectron density, ne and ion species nH
H,He operation if puffing is not sufficient
Source of HSH < 100Pam3/s ???
2 injectorsPellet sizes:V=92/50/33/17 mm3Frequency: 4-16 HzVariation ~ factor of 2 in 3 s
70 ms(flight in tube for 300 m/s HFS pellet).
Core/penetration to center ~ 0.2 – 4 TauE [3]
SOL/Div~ 10 ms
ELM pacing,Gas puffing,Div control,ICRH,Pumping
/All~ 10 ms
ELM pacing,Gas puffing,Div control,Pumping
/ All~ 10 ms
9J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Fuelling and Impurity Control – 2: Gas
ActuatorPlasma parameter controlled
Availability(conditions in which it is required)
Actuator output controlled
RangeHardware dynamic limits
Hardware response time
Target area /Response time
Affected area /Response time
Affected actuators /Response time
Affecting actuators
Gas puffing
Electron density, ne and main ion species nH, nD, nT
For H, DD and DT operation respectively
Fluxes, SK of H2, D2, DT, T2
SUM(SK) < 200/400 Pam3/sAver/peaked (10 s)
< 1 s (63%) [2] < 1 s
Core/penetration to center ~ 0.2 – 4 TauE [3]
SOL/Div~ 10 ms
LFS ELM pacing,Pellet fuelling,Div control,ICRH,Pumping
/All~ 10 ms
LHS ELM pacing,Pellet fuelling,Div control,Pumping,Pellet impurity/All ~ 10 ms
Gas puffing
Hydrogen minority nH, control for ICH heating(contributes to ne)
Half field operation in He, DD and DT with ICRH
H2 flux, SH
SH/SD+T>0.5% in DD, DT(mix purity),SH <200/400 Pam3/sAver/peaked (10 s)
< 1 s (63%) [2] < 1 s
Core/penetration to IC resonance (depends on IC frequency) ~ 0.2 – 4 TauE [3]
SOL/Div~ 10 ms
LFS ELM pacing,Pellet fuelling,Div control,ICRH,Pumping,Burn control
/All~ 10 ms
Sources from H-NBI, DNB, (< 0.4 Pam3/s each)ELM pacing & fuelling by H-pellets,Div control,Pumping
Gas puffingElectron density, ne and n4He density
4He phase operation
4He flux, S4He S4He < 120 Pam3/s
< 1 s (63%) [2] < 1 s
Core/penetration to center ~ 0.2 – 4 TauE [3]
SOL/Div~ 10 ms
Div control,ICRH,Pumping
/All~ 10 ms
Div control,Pumping
/All~ 10 ms
Gas puffing
3He minority n3He, control for ICH heating(contributes to ne)
ICRH minority heating for full field operationin H,He,DD,DT
3He flux, S3He S3He < 60 Pam3/s
< 1 s (63%) [2] < 1 s
Core/penetration to IC resonance (depends on IC frequency) ~ 0.2 – 4 TauE [3]
SOL/Div~ 10 ms
Div control,ICRH,Pumping,Burn control
/All~ 10 ms
Div control,Pumping
/ All~ 10 ms
10J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Divertor Heat Flux and Radiation Control
Actuator SensorPlasma parameter controlled
Actuator output controlled
Caveats Response time
Availability(conditions in which it is required)
Dynamic Requirement
Impurity injection (Ar, Kr)
core foil bolometer system
Total core radiationmedium-Z impurity gas flux
possible energy confinement degrad.
50 msseparatrix power flux well above H-L threshold
Real-time total core radiated power
Impurity injection (N, Ne)
divertor foil bolometer
Total divertor radiation
low-Z impurity gas flux
core dilution 20 mshigh divertor power
Real-time divertor power
deuterium gas injection (main chamber or divertor)
pressure gauge, better: spectroscopic recombination monitor
divertor neutral pressure
D gas flux
possible confinemen degradation, load on gas plant
20 ms partial detachmentif available, recombination qualifier from Balmer line ratios
Impurity injection (N, Ne)
IR camera peak heat fluxlow-Z impurity gas flux
challenging for real time, core dilution
1 mshigh divertor power
real-time heat flux evaluation
Impurity injection (N, Ne)
divertor Te, e.g. from spectral Line ratio, probes ?
degree of recombination/detachment
low-Z impurity gas flux
Te calculation perturbed b y ELMs
20 mshighdivertor power
real time Te calculation
Impurity injection (N, Ne)
target currentouter divertor temperature
low-Z impurity gas flux
sensor ? 1 mshigh divertor power
Area: Detachment and target heat flux controlDescription: Actuator specifications required or supplementary to control the target heatflux and/or degree of detachmentLeader: A. Kallenbach (EU)
11J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Rotation Profile Control
ActuatorPlasma parameter controlled
Actuator output controlled
Category (MP, BC, AC)
Range Response timeTotal Latency
Availability(conditions in which it is required)
Flattop Requirement
NBI rotation profile NBI torque, 0-35Nm AC NBI 0-33 MW 100ms 1000msAny rotation profile
RMP coil braking rotation profile RMP coil current AC0-max coil current
10ms 500 ms
Not work very close to the neo-claasical offset rotation
If it gives a rotation change, on AUG, no rotation change observed
ICRH power, minority heating scheme
rotation profile ICRH power AC 0-20MW 10ms 1000msDepends on the ICRH heating scenario
ICRH mode conversion flow drive
rotation profile He3 concentration AC 0-20MW 10ms 500msonly when using He3 ICRH heating scenarios
only under certain He3 concentration
ECRH rotation profile ECRH power AC 0-20MW 10ms 300mspriority probably on other control with this actuator
ECRH rotation profile poloidal steering angle AC min-max 100ms 400mspriority probably on other control with this actuator
within the limit of steering the angle in real-time
Pellets rotation profile pellet frequency AC 0-6Hz 50ms 500msnot valid near Greenwald density
effect of pellet on density may restrict this
Area: Rotation Profile ControlDescription: Actuator specifications required or supplementary to control the toroidal plasma rotation radial profileLeader: T. Tala (EU)Contributors: P. Mantica (EU), D. Moreau (EU), W. Solomon (US), N. Hawkes (EU)Reviewers: J. Snipes (IO)
12J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Current Density Profile Control
ActuatorPlasma parameter controlled
Actuator output controlled
Category (MP, BC, AC)
RangeResponse time
Total Latency
Availability(conditions in which it is required)
Dynamic Requirement
ICRH q profile Power AC 0-50 MW 250ms 250ms any timereal-time optimized power
NBI q profilePower (Beam modulation algorithm)
AC 0-20 MW 500ms 500ms any timereal-time optimized power
EC system q profilePower (Gyrotron modulation algorithm)
AC 0-20 MW 250ms 250ms any timereal-time optimized power
EC system q profile Miror angle AC 0-max 250ms 250ms any timereal-time optimized miror angle
Loop Voltage q profilePrimary coil current
AC 0-40 kAt 500ms 500ms any timereal-time optimized coil current
LH q profile Power AC 0-20 250ms 250ms any timereal-time optimized power
LH q profilerefractive parallel index
AC 1,8-2,2 250ms 250ms any timereal-time optimized refractive index
Area: Current Density Profile ControlDescription: Actuator specifications required or supplementary to control the plasma current density profileLeader: D. Mazon (EU)Contributors: D. Moreau (EU), N. Hawkes (EU)
13J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Temperature Profile Control
ActuatorPlasma parameter controlled
Actuator output controlled
Category (MP, BC, AC)
RangeResponse time
Total Latency
Availability(conditions in which it is required)
Flattop Requirement
Dynamic Requirement
Notes
EC system (off-axis), NB or IC system (on-axis)
Temperature profile
Aiming angles (EC), total power output (all)
EC aiming (full range), Total power (0-max)
1-5 s Current rise phase (all scenarios)
Real-time optimized waveforms
[1]
EC system (off-axis), NB or IC system (on-axis)
Temperature profile
Aiming angles (EC), total power output (all)
EC aiming (full range), Total power (0-max)
1-5 s Baseline scenario
50 MW total power
Maintain burn or target stored energy
[2], [3]
EC system Parallel currentAiming angles, power
Full range 1-5 s Steady state scenario
Must maintain burn and total non-inductive current drive
[4]
IC systemPlasma rotation (poloidal?)
Power, frequency Full range 1-5 s All scenarios, but primarily steady state
Must maintain burn and total non-inductive current drive
[5]
Notes Expanded Details[1] Need feed-forward and feedback control in the current rise, especially for advanced scenarios[2] Looking for changes to the parallel conductivity profile to avoid tearing modes[3] Heating profile will have weak response in Q=10 plasma due to strong central heating from alphas
[4]Speculative scheme for steady state uses strong temperature profile response to reversed shear to meet Q=5 steady state goal. Must control reversal point.
[5] Speculative scheme for confinement uses driven poloidal flows by ICRF to alter the energy transport locally
Area: Temperature Profile ControlDescription: Actuator specifications required or supplementary to control the amplitude and frequency of ELMsLeader: T.C. Luce (1st draft writer)Contributors: J. A. Snipes (IO)
14J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Pressure Profile Control
ActuatorPlasma parameter controlled
Actuator output controlled Response timeAvailability(conditions in which it is required)
Notes
ECH Te,Ne power and antenna aiming >.5s all scenarios [1],[2],[3]
NBI Te, Ti, momentumpower at a given beam aiming
> .5s all scenarios [1],[2],[4]
ICH Te, Ti spectrum >.5s steady-state [1],[2],[4]
pellet ne size and rate of pellets few Hz all scenarios [1],[2]
current density control J or q to alter transport see current density hybrid and steady-state
[1],[2],[4],[5]
rotation controlmomentum to alter transport
see momentum hybrid and steady-state
[1],[2],[4],[6]
fueling control ne see fueling&impurtiy all scenarios [1],[2],[7]
temperature control Te,Ti see Temperature all scenarios [1],[2],[8]
Area: Pressure Profile Control
Description:Actuator specifications required or supplementary to control the plasma pressure profile, plasma stored energy, and fusion burn
Leader: T. Casper (IO)Contributors: D. Moreau (EU), M. Beurskens (EU), N. Hawkes (EU)
15J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
ELM Control
ActuatorPlasma parameter controlled
Actuator output controlled
Category (MP, BC, AC)
RangeTotal Response time
Total Latency
Availability(conditions in which it is required)
Flattop Requirement
Dynamic Requirement
Pellet injection ELM frequency Pellet size MP1-4×10^21 D particles
20 ms
10-30% inter-ELM period
Ip > 6 - 9 MA
Minimal fueling
Real-time optimized pellet size
Pellet injection ELM frequencyPellet repetition rate
MP 30 - 60 Hz 20 ms
10-30% inter-ELM period
Ip > 6 - 9 MA
DW_ELM < 0.7 MJ
Real-time optimized repetition rate
Pellet injection ELM amplitude Pellet velocity MP1-4×10^21 D particles
20 ms
10-30% inter-ELM period
Ip > 6 - 9 MA
300 - 500 m/s
Real-time optimized pellet size & speed
Resonant Magnetic Perturbation
ELM amplitude ELM coil current MP0-90 kAt peak
150 ms 100 msIp > 6 - 9 MA
90 kAt peak 5 Hz rotation
VS in-vessel coils
Vertical position jogs
VS coil current MP0-40 kAt RMS
150 ms 100 msIp > 6 - 9 MA
T_coil < 160 °C
6 cm, 50 Hz
EC system ELM amplitude EC power MP 0-7 MW 150 ms 100 msIp > 6 - 9 MA
Area: ELM ControlDescription: Actuator specifications required or supplementary to control the amplitude and frequency of ELMsLeader: J. A. Snipes (IO)Contributors: A. Loarte (IO), Y. Gribov (IO), J. Lister (EU)
16J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
NTM Control
ActuatorPlasma parameter controlled
Actuator output controlled
Category (MP, BC, AC)
RangeResponse time
Total Latency
Availability(conditions in which it is required)
Flattop Requirement
Dynamic Requirement
ECCDm=2,n=1 Mirnov amplitude
Mirror poloidal position
BCplus or minus one degree
three degrees per sec
no more than 24 msec (0.1 sweep time)
Ip>6-9 MA
Mirnov amplitude less than 5G (w=1.4 cm)
Find and set alignment by "target lock"
ECCDm=2,n=1 Mirnov amplitude
EC power BC 3-6 MW
no more than 24 msec (0.1 sweep time)
no more than 24 msec (0.1 sweep time)
Ip>6-9 MASufficient EC power pulsed on
Find and set alignment by "target lock"
ECCDAlignment of ECCD on q=2
Mirror poloidal position
BCplus or minus 0.5 degrees
three degrees per sec
no more than 30 msec (time to 1.4 cm wo ECCD)
Ip>6-9 MAAlign to 0.5 cm or less
Measure q=2 and ECCD locations
ECCDAlignment of ECCD on q=2
EC power BC >3.5 MW CW_________
Ip>6-9 MASufficient EC power maintained
______________
Area: Neoclassical Tearing Mode ControlDescription: Actuator specifications required or supplementary to control classical and neoclassical tearing modesLeader: R. La Haye (US)Contributors: R. Buttery (US), O. Sauter (EU)
17J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Alfvén Eigenmode Control
ActuatorPlasma parameter controlled
Actuator output controlled
Category (MP, BC, AC)
RangeResponse time
Total Latency
Availability(conditions in which it is required)
Flattop Requirement
Dynamic Requirement
Notes
active coils (such as RMP coils with high frequency capabilities)
BetaPrimeAlpha (= radial gradient of the alpha particle pressure profile)
current and voltage of active coils
AC
I_coil: up to ~50A-peak (AC)V_coil: up to ~3kV-peak (AC)frequency: ~50kHz to ~300kHz
under ~10ms + RF shielding effect of blanket modules
2ms to 5ms + RF shielding effect of blanket modules
(1) all DT shots(2) should be tested on non-DT shots with NBI/ICRF fast ions replacing alphas
control over flat-top should not be needed if discharge scenario is setup to avoid high amplitude AEs
d(I_coil)/dt~50A/msec (value will be limited by voltage rise on active coils and coils' self inductance)
need capability for reliable real-time measurement for advanced control. (see "Notes" below for further details).
plasma shaping coils
BetaPrimeAlpha (= radial gradient of the alpha particle pressure profile)
current and voltage of plasma shaping coils
AC
asking for <5% variation in edge elongation, should be within present capabilities of plasma shpaing coils (as currently in JET)
under ~10ms + RF shielding effect of blanket modules
2ms to 5ms + RF shielding effect of blanket modules
(1) all DT shots(2) should be tested on non-DT shots with NBI/ICRF fast ions replacing alphas
control over flat-top should not be needed if discharge scenario is setup to avoid high amplitude AEs
need <5% variation in edge elongation within 10ms, should be well within present capabilities of plasma shaping coils (as in JET)
need capability for reliable real-time measurement for advanced control. (see "Notes" below for further details).
ECCD system
BetaPrimeAlpha (= radial gradient of the alpha particle pressure profile)
ECCD power and injection angles
ACdifficult to estimate, would require detailed modelling
under ~50ms
10ms to 25ms
(1) all DT shots(2) should be tested on non-DT shots with NBI/ICRF fast ions replacing alphas
control over flat-top should not be needed if discharge scenario is setup to avoid high amplitude AEs
difficult to estimate, would require detailed modelling
need capability for reliable real-time measurement for advanced control. (see "Notes" below for further details).
Area: Alfvén Eigenmode ControlDescription: Actuator specifications required or supplementary to control the effects of Alfvén eigenmodes on fast ion transportLeader: D. Testa (EU)Contributors: A. Fasoli (EU)Reviewers: J. Snipes (IO)
18J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Shared Actuators: Leader – Dave Humphreys
Actuator
Plasma/machine characteristics, parameters controlled1
Intermediate control/sensed variables
Actuator outputs controlled
Shared Actuators3 Type of Sharing2
Category (MP, BC, AC)
RangeRepurposing Time
Flattop (Scenario) Requirements
Dynamic Requirements
Notes
PF power supplies
Equilibrium shape + divertor/strikept geometry + Ip + li + (vertical stability)4 + (RE control)
Gap distances, strikept locations, vertical position
PF PS currents PF PS SMM MP, BC N/A ???
Robustness dynamic requirements still not analyzed? Possibly will increase demand on PF PS (esp. req on stkpt accuracy with disturbances)
PF circuitEquilibrium control -> RE control
Gaps -> RE position/current
PF PS currentsPF PS -> BD resistors?
RP MP? 100 ms N/A100 ms RP time
Scenario: repurpose PF's from gap control to RE position/current control (possibly including re-switch in of BD resistors to extract current from divertor coils to drop decay index)
VS3 power supply
Vertical stability + divertor heating
Vertical velocity (position), ELM frequency
VS3 PS voltage/current
N/A RP (SMM?) MP, BC 0-240 kAt 5 ms ??? 5 ms RP time
VS control + Vertical jog oscillation SMM, assume same peak current requirement, but RP requirment comes from need to detect and repurpose for full amplitude VDE suppression
EC launcher mirrors
m/n=2/1 island amplitude + current profile characteristics + sawtooth stability
ECCD alignment with island, location of deposition
Launcher mirror poloidal angles, injected power, modulation frequency
Midplane launchers, NBI
RP BC/AC5
plus/minus 20 degrees? 0-9 MW?
100 ms ???6-10 deg/sec unidirectional slew rate?
Scenario: Repurpose from profile control + sawtooth suppression to 2/1 NTM suppression (requires more time to RP and align)
EC launcher mirrors
m/n=2/1 island amplitude + current profile characteristics + sawtooth stability
ECCD alignment with island, location of deposition
Launcher mirror poloidal angles, injected power, modulation frequency
Midplane launchers, NBI
SMM BC/AC
plus/minus 20 degrees? 0-12 MW?
Higher peak power?
Alignment accuracy +/- 0.5 cm? (if no higher peak power)
Scenario: SMM, assume 1/2 power to profile control/sawtooth control, 1/2 power to NTM suppression (requires faster and higher accuracy alignment?)
Pellet launchers
Fueling + ELM pacing +Disr Mitig + RE damping
Density, ELM freq,, relative stability, RE current
Launcher triggers
multiple pellet launchers
RP (SMM?) BC ??? ???Scenario: repurpose from Flattop operation to disruption mitigation /control mission
RMP coils
ELM control + EFC + LM rotation + RE deconfinement
ELM amplitude, NTM amplitude/ rot. Frequency
RMP coil PS currents
N/A SMM BC0-120 kAt peak
Speculate need additional 30 kAt for EF correct, LM rotation
RMP coils
ELM control + EFC + LM rotation +( RE deconfinement)
ELM amplitude, NTM amplitude/ rot. Frequency -> RE current
RMP coil PS currents
N/A RP BC0-120 kAt peak
Scenario: Repurpose from flattop SMM's to deconfinement of RE
MGIDisruption mitigation + (RE damping)
RE currentimpurity gas flow timing, (rate)
multiple gas species, gas valve, rupture disk
RP, SMM MP0-10000 torr-liter? Ne/He?
Scenario: repurpose from initial disruption mitigation to post-TQ RE damping (or SMM action prior to TQ?)
19J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
What Should the Final IPCWG Document Contain?
The document produced by the IPCWG should state what are the minimum actuator and diagnostic requirements that are necessary for the PCS to control ITER plasmas for the non-active, inductive, Hybrid, and steady-state DT scenarios concentrating particularly on H&CD profile control, fueling, and impurity control
It should also compare those necessary requirements with actuator and diagnostic requirements and limitations as specified in the
ITER baseline documents (Project Requirements, SRD’s, etc)
It should point out any discrepancies that are likely to compromise any of the PCS control functions for any of these scenarios
Suggestions should then be proposed that could either recover the PCS control function in question or propose an R&D plan to try to find a way to resolve the issue
20J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
IAEA Technical Meeting on Plasma Control
Paper presented on Actuator and Diagnostic Requirements of the ITER PCS at the IAEA TM on Plasma Control, June 2011
Submitted for publication to Fusion Engineering and Design
This paper covered the main actuator and diagnostic requirements of the PCS that have been studied to date including:
• Magnetic control requirements
• Specific limitations of the H&CD and fueling and pumping systems
• A summary of the MHD control diagnostic requirements assessed by the MHD ITPA WG4
• A summary of the WG3 sawtooth control requirements
21J A Snipes, 7th IOS ITPA Meeting, Kyoto, Japan 18 – 21 October 2011
Need to Include all Control Areas
The PCS CDR must cover all control areas expected for ITER operation in inductive, Hybrid, and steady-state scenarios
To complete the PCS control areas, additional leaders have been nominated for the remaining PCS control topics:
Control Area Leader
Axisymmetric Magnetic Control L Zabeo (IO)
Error Field Control M Schaffer, S Sabbagh (US)
RWM Control S Sabbagh (US)
Disruption and Runaway Control and Mitigation S Putvinski (IO)
Sawtooth Control I Chapman (EU)
Wall Conditioning M Shimada (IO)
Anyone else who would also like to contribute to this effort in any control areas, please send me their name and area