Transcript Stabilisation of magnetic islands with Electron Cyclotron

FOM-Institute for Plasma Physics Rijnhuizen
Association Euratom-FOM
Introduction to fusion control
Tony Donné
Association Euratom-FOM
Control is a central issue in fusion
• Research in present devices points strongly
towards need for advanced control
– Simultaneous control of multiple (profiles of) plasma
parameters
– Real-time control of a large number of parameters
with a limited set of actuators
– Profile control in the presence of dominant alpha
heating
– Control signals for feedback on one parameter
derived from multiple diagnostics
– Intelligent control taking account of the instrumental
response functions
A.J.H. Donné, Control for Nuclear Fusion, 7/8 May 2008
2/9
Association Euratom-FOM
Control is a central issue in fusion
• Let’s look at ITER measurements to
illustrate this
A.J.H. Donné, Control for Nuclear Fusion, 7/8 May 2008
3/9
Association Euratom-FOM
Operating
Scenario
Special Features
Required Measurements
H phase.
Inductive.
Ohmic L mode.
Limited H Mode
D phase.
Inductive. ELMY
H mode
High power D/T
phase.
Inductive. ELMY
H Mode
Plasma shape and position, vertical speed, Btor, Ip, Vloop,
locked modes, m = 2 modes, low m/n MHD modes, q(a),
halo current, line-averaged density, runaway electrons, impurity identification and influx, ne(r) and Te(r) in core, Ti in
core, surface temperature of divertor plates and first wall,
Prad from core, line-averaged Zeff, H/L mode indicator, gas
pressure and composition (divertor and duct)
As above plus: , q(95%), ELM occurrence and type, ne(r)
and Te(r) at edge, Pfus, Prad(r), heat deposition profile in divertor, divertor detachment
As above plus: shape and position (500 s), Ti & Te in core,
Pfus, Prad, neutron and alpha source profiles, vtor(r) and
vpol(r), impurity profile, Ti(r) in core, Zeff(r), nHe(r), nHe in divertor, nT/nD in core, D and T influx, divertor ionisation front
position, neutral density (near wall), ne and Te in divertor,
impurity and DT influxes in divertor with spatial resolution,
alpha loss, neutron fluence, erosion of divertor tiles
As above plus: localisation of q = 1.5 and q = 2 surfaces,
high sensitivity measurements of ne and Te, detection and
measurement of NTMs
As above plus: shape and position (for 1000 s)
Conclusion
Exploration of H mode
and initial fusion operation
Full exploration of H
mode and fusion performance
The more advanced the operating
scenarios,
the more parameters need to be
controlled
D/T Phase.
Extension to high  inInductive ELMY H cluding stabilisation of
mode. High 
NTMs
Hybrid operation Extension to long pulse
using current drive
Steady state opExtension to steady state As above plus: q(r) (in particular location & value of qmin),
eration
using current drive, stahigh resolution measurements of the gradient of Te and Ti,
bilisation of NTMs and
measurement of RWMs
RWMs, and possibly
A.J.H. Donné, Control forITBs.
Nuclear Fusion, 7/8 May 2008
4/9
FOM-Institute for Plasma Physics Rijnhuizen
Association Euratom-FOM
P. Politzer et al., ITPA meeting Lisbon 2004
Association Euratom-FOM
The (hopefully not too) far future:
DEMO
• Only 1-2 operating scenarios
– Smaller number of measurements/diagnostics
– Advanced predictive/analysis codes to combine data from
various diagnostics in an intelligent way are needed to reduce
the number of required diagnostics. Experience with this should
be gained on ITER
• Experience on ITER may guide the selection of
techniques that can best cope with the harsh
environment
• During ITER life time experience should be gained with
real-time data handling and validation to process large
quantities of data, in-pulse calibration, etc.
A.J.H. Donné, Control for Nuclear Fusion, 7/8 May 2008
6/9
Association Euratom-FOM
DEMO: no Diagnostic Neutral Beam?
• In case the data obtained in ITER with the DNB (He-ash,
Ti, vrot, Bp, etc.) are important for DEMO, techniques and
hardware should be developed to obtain the same info
without beam
– E.g., is it possible to use measurements of He near
the edge to control the He ash?
A.J.H. Donné, Control for Nuclear Fusion, 7/8 May 2008
7/9
Association Euratom-FOM
This workshop
• Position and shape control
– Equilibrium, stability
• Profile control
– Performance boosting, plasma tailoring
• MHD control
– Stability, ‘controlability’ (i.e. tolerable ELMs)
• Integrated scenarios
A.J.H. Donné, Control for Nuclear Fusion, 7/8 May 2008
8/9
Association Euratom-FOM
I wish you all a very interesting workshop
A.J.H. Donné, Control for Nuclear Fusion, 7/8 May 2008
9/9