r. a. pitts 1 5 th eu-pwi tf meeting ljubljana, 13/11/2006 jet task force e: what we do and how we...

R. A. Pitts 1 5th EU-PWI TF Meeting Ljubljana, 13/11/2006

JET Task Force E:what we doand how we do it

R. A. Pitts on behalf of TF-E

13 November 2006


OUTLINE

• Brief word on EFDA-JET structure

• Main activities of TF-E– Details in SEWG reports this morning– Experiment

• Diagnostics specific to TF-E interests

– Theory/modelling

• Current programme– 2006 (C16-C17)– Early 2007 (C18-C19)


About 300 different European physicists and collaborators from USA, Japan, Russian Federation, China conduct experiments on JET.

A facility collectively used in preparation of ITER

Participation of European Physicists in JET early 2006 Experimental Campaigns

UKAEA17.7%

IST7.1%

IPP6.8%

IPPLM2.1%

HUNG0.3%

HR0.9%

Bulg0.7%

RISO0.9%

BELG3.6%

FZJ6.8% FOM

0.8%

CSU-G1.0%

ENEA16.5%

CRPP4.2%

CZEC1.1%

CEA8.3% CIEMAT

4.1%

MEC1.4%

OAW0.4%

TEKES4.3%

VR11.1%

JET under EFDA


Task Force organisation• Scientific activities organised into Task Forces:

– 2 Task Forces for ITER scenarios (S1 and S2)– Topical or “Physics” Task Forces:

M (MHD) Expts. and codesT (Transport) Expts. and codesE (Exhaust) Expts. and codes, strong link to EU-PWID (Diagnostics) Expts. and diag. developmentsH (Heating)FT (Technology) Strong link to EU-PWIDT (DT experiments)

• In addition, a significant ongoing code integration project (led by Vassili Parail)– Since C15-C17 Campaigns, Physics Task Force activities are

“Channelled” by S1 and S2 – experiments organised into “S1 weeks” and “S2 Weeks

– Experiments programme always organised around “agreed/planned” sessions plus 20% contingency, allocated by S1, S2 after discussion with Physics TFL’s


Programme Elaboration

• Any particular set of experimental campaigns defined in 3 steps:– 1) define the main objectives (EFDA with Task

Force Leaders, approved by Committees)– 2) details of the programme results from call for

scientific proposals sent to all Associations / proposals selected with Task Force Leaders

– 3) participation in experiments following a call for participation sent to all Associations

• Step 3 now ongoing for Campaigns C18-C19 in first 3 months of 2007


What does TF-E do?

• All aspects related to the physics of plasma-wall interaction and SOL/edge transport on JET

• We have attempted to retain a significant edge modelling effort within the Task Force– Rather than “farm out activities elsewhere (e.g. TF-T) – Edge modelling has strong connection to “surfaces” – i.e. not purely a

“transport” phenomenon– Enormous scope of modelling activity

• We retain a strong independent contribution to transients (ELMs/disruptions) but strong inter-TF cross-over there (S1, M, S2 …)

• Gas balance/material migration/erosion/deposition T-retention• Growing recent involvement with S2 in the drive to characterise

edge/SOL conditions in advanced scenarios– It is becoming inceasingly evident that S1 and S2 are converging in many

aspects of scenario development (e.g. Hybrid regime)– SOL of advanced scenario plasmas very poorly diagnosed worldwide,

despite obvious importance to magnetic fusion– Lots of room here for involvement of “new blood”

• Diagnostic development and upgrade• Support EU-PWI-TF and physics preparation for ILW


Wall interaction diagnostics

Divertor IRTile thermocouplesLangmuir probes

Wide angle main chamber and vertical divertor viewing IR(upgrade of vert. system in 2007)

Fast reciprocating probes: TTP, RFA


Range of visible spectroscopy

Plays an important role in studies of impurity evolution, material migration, impurity screening, ELM dynamics


Significant upgrade to bolometry system

A. Huber et al., SOFT 2006

• More viewing chords– Increased sensitivity (lower noise)– Higher time resolution (~2 ms cf.

~20 ms for old system)– Higher quality tomography

• ELM energy deposition can now be resolved b e t w e e n E L M s

d u r i n g E L M

R ( m )

R ( m )


New DMV system now commissioned

K. H. Finken, A. Savchkov et al., FZJ

• Disruption mitigation valve project now closed (as of 6th Nov. 2006) – officially handed over to UKAEA Operator – First dedicated experimental session on

JET Friday this week! Will investigate effect of Ar as runaway electron mitigator

– Initially only Ar, Ne will be allowed– Work underway to allow use of D2/gas

mixtures– Helium only in much longer term– Long (~4m) tube length from valve means

“real time” use not possible with heavier gases

– Use of D2/different gases in backing volume might make this possible in 2007

• Session planned in March 2007 for Tritium recovery by gas termination


#66562 • 640x512 pixels• 100 Hz full frame• 128x8 subarray at

10 kHz• 200 2300ºC• Min. exposure

time 20 s– Being used now

to study main wall and divertor power loads during ELMs and disruptions

Exciting new wide-angle IR system (KL7)

• ITER-like optical design

• f ~ 4• FOV 35º

E. Gauthier et al., CEA Cadarache


Example movies (#67384)

Normal frame Difference frame

• 100 Hz frame-rate, but 300 s snapshot catches an occasional ELM


First wall ELM filament impact • Filaments now being seen routinely as campaigns advance• Camera generates huge amounts of data – large effort required

Ip = 2 MA, B = 3TWELM ~ 150 kJ

Two discharges with different contact point of first limiting flux surface

#66560, 5.548s

P. Andrew, G. Arnoux

Coord. Transformation (x,y) (,)

#67384, 26.225s


New EP2 Fast Camera project (FC7)

C. Hidalgo, J. A. Alonso, CIEMAT

• Fast Photron APX-RS CMOS camera– 3000 fps full frame

(1024x1024)– 250,000 kHz in sub-

array (16 x 128)– down to 1 s exposure– first tests with CIEMAT

camera, JET device arrives in 2007

• ELM visualisation and PWI (impurity influxes – using filters on selectable wheel)

Split view from KL7 periscope (before Cassegrain mirror


Also good divertor IR (KL3b)

• ELM resolved target heat flux (IR)– Type I ELM energy

deposition strongly favours INNER target for FWD-B

– For REV-B, some evidence for more balanced deposition,

– Consistent with similar analysis from AUG (WELM < 20 kJ) and linked to passage of net current through target plates

T. Eich et al., PSI 2006


Divertor Langmuir probes

S. Jachmich, FZJ

• Full upgrade of gas box divertor probes (KY4D) During 2004-05 shutdown– New Load Bearing

Septum Replacement Plate (LBSRP) now fully equipped

– Triple probe capability restored

• Room for more effort here for interested secondeesAfter C16 and 4 weeks of C17, 62 out

of a total of 86 probes still survive


1

3

4 6

7

8

LBSRP

QM

B 1

,2,3

QMB 4

QM

B 5

QMB 6

Divertor QMB’s

• 5 more QMB’s installed following succesful prototype in inner divertor during MarkIIGBSRP campaign.– Only 2 out of 6 now survive only QMB 1 (replacement for original

inner divertor QMB) useful for physics studies

G. Esser et al., FZJ


6/11/06

0

20

40

60

80

100

120

6832

2

6832

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6832

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6832

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6832

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6832

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6833

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6833

1

6833

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6833

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6833

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6833

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6833

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6833

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6833

8

Shot

Hz/

s Vertical Target

N2N2

PNBI=7.6 MWELM Type I

PNBI=4.7 MWELM Type III

PNBI=7.6 MWELM Type I

Even one QMB teaches us a lot!

N2

HT

Vertical TargetVertical

Target

HTHT

HT(sweep)

VT

Hz/

s

From TFE contingency session (06/11/2006)

HT


Edge Modelling within TF-E• Significant edge modelling activity within TF-E

– Regular “edge modelling months” during experimental campaigns when large groups of modellers come together on secondment

– Last was Feb. 2006, next Feb-March 2007

• Activites cover the whole range of edge physics modelling with suite of codes– Main drive in a number of specific areas:

SOL flowsdrifts

Code-code benchmarking

Erosion redeposition

Transients:ELMs/disruptions

Turbulence(with TF-T)

EDGE2D-NIMBUSEDGE2D-Eirene

SOLPS5 (B2.5-Eirene)BIT1

EDGE2DSOLPS5

ERO

BIT1 (kinetic)SOLPS5EDGE2DAnalytic

ESELGEM


PIC simulations of ELM losses• More realistic description of the

ELMy JET SOL using improved PIC simulations (BIT1 code)– Scan in Tped, nped to vary WELM – Most of the heat flux arrives with

ions on the acoustic timescale– BUT, only ~30% of ELM energy

deposited when qtarget peaks– Electrons account for ~30% of

target energy deposition– Strong transient increase over

“Maxwellian” sheath transmission factors during the ELM

– Fluid code assumption of fixed underestimates qtarget at high WELM

Example: Tped = 1.5 keV, nped = 1.5x1019m-3

WELM ~ 120 kJ, ELM = 200 s D. Tskhakaya


Current Programme (C15-C19)• Original programme due to start in late 2005 and finish in April

2006– multiple delays pushed start of campaign (C16) to 25 September after a

very short and essentially useless C15– C16-C17 from 25/09 15/12– 80 total sessions + 20% contingency– “spillover” from C16-C17 into C18-C19 + additional time granted up to

2007 shutdown for installation of ITER-like ICRH antenna

• C15-C17 were the subject of call for proposals.• C18-C19 has been planned mostly by the Task Forces, without

call for proposal– C18-C19 from 08/01 30/03/2007– 89 sessions + 5 + 20% contingency– Call for manning sent to Associations on 06/11/2006

• TF-E won an allocation of 20 sessions (pure TF-E) from a total of 160 (not incl. contingency) 12.5% proposal– Historically about what we usually hope for


TF-E allocation in C18-C19• TF-E experiments in 2006/07 divide naturally into 3 main

programmatic areas:

ELMs Wall Physics Disruptions

Small ELM regimes:“Convective” ELMs

Type III ELMs with N2 seeding

Material ablation by large ELMs

ELM-main wall interaction

Gas balanceMaterial migrationLocal erosion and

redepositionBe transport

MitigationRunaway suppression

(DMV)

11 sessions

6 sessions

3 sessions

Already gained ~2 extra sessions for wall physics through contingency time when beam power failed!


C18-C19 a challenge to TF-EExperiments schedule – TFE heavily involved

Pure TF-E Strong TF-E support

TF

-ripp

le expts


Please come andlend ahand(or two)!!

Association manning response for 20 November!!!

r. a. pitts 1 5 th eu-pwi tf meeting ljubljana, 13/11/2006 jet task force e: what we do and how we...

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