D. Tskhakaya ADAC meeting, Cadarache 24.9.2012 1/16 Molecular Data in Tokamak edge Modelling D. Tskhakaya Association EURATOM-ÖAW, University of Innsbruck,

D. Tskhakaya ADAC meeting, Cadarache 24.9.2012 1/16

Molecular Data in Tokamak edge Modelling

D. Tskhakaya

Association EURATOM-ÖAW, University of Innsbruck, A-6020 Innsbruck, Austria

Andronikashvili Institute of Physics, 0177 Tbilisi, Georgia


Molecular sources

Processes involving molecules

Requirements to the molecular data

Needs for kinetic modeling of the plasma edge

Conclusions

Outline


Molecular sources in the SOL

JET

Plasma-facing components (PFC): chamber walls, divertor plates,

RF antennas, …


Molecular sources in the SOL

„Conventional“ tokamaks

AUG, DEMO (?)

JET, ITER

Tokamaks with liquid walls

C (CFC), Fe, …

W

Be

W

LiGas puffing (e.g. D2)


Molecular sources in the SOLPlasma recycling

Wall

D+ A Wall Surface

C, W : A= D2 (>90%)

Be: ?

Li: R~0For DT operation

A= D2, DT, T2

At low energies isotope effects might be important!

H2+ + H2 H3

+ + H D3+, T3

+, TD2+, DT2

+


Molecular sources in the SOLImpurity sputtering

Wall

B AWall Surface

C (chemical sputtering): B= Dm

A= CnDk

W: ?

Be [Björkas PSI 2012]: B= D

A= BeD (<60%)

A= BeD2 (<40%)For DT operation

A= BeD, BeT, BeD2, BeT2


Molecular sources in the SOLImpurity seeding, etching

N2 , O2 , NO2

Molecules to be taken into the account in fusion plasma edge modeling

D2, DT, T2 ,

BeD, BeT, BeD2, BeT2

N2 , O2 , NO2

CnDmTk

D3+, T3

+, TD2+, DT2

+


Processes in the plasma edge involving molecules

e + M e + M Elastic

e + M e + M* Excitation (electronic, vibrational,

rotational)

e + M 2e + M+ Ionization

e + M e + A + B Dissociation

e + M e + A+ + B Dissociative ionization

e + M+ A + B Dissociative recombination

e + M A- + B Dissociative attachment

A + M A + M Elastic

A + M A + M* Excitation

A+ + M A + M+ Charge exchangeA + M+ A+ + M Charge exchange

A + M A + B + G Dissociation

A- + M A + M + e Electron detachment with moleculeM - molecule (in some excitation/ionization state)

A – molecule, ot atom (in some excitation/ionization state)


Requirements to the data

Fluid, or fluid/kinetic models (e.g. B2-SOLPS, ERO, EIRENE, …)

MAMaxwell-distributed

particle pool

B

Rate coefficients (averaged over initial/final excitation-states) are required

eM

Mnn

VV

VdTVfvvVVvvTR

,,...',,,...',,

Data source: ADAS, …


a

b

c

d

a

b

c

d

e

a

b

,E 211 ,,, EE 32121 ,,,,, EEE

Full kinetic models (PIC/MC)

Requirements to the data

10-4

10-3

10-2

10-1

100

10-3

10-2

10-1

100

101

102

KrsticBIT1

[r]

sin [a.u]

2/sin11ln4

1,2

aE

aE

aEd

Ed

Differential cross-sections

for H++H2 elastic collision

implemented in BIT1 code

Data source: any available


Electron/ion VDFs in the SOL [Tskhakaya CPP 2012]

-2 -1 0 1 2

x 107

10-4

10-3

10-2

10-1

100

f e(v||)

V|| [m/s]

2 mm10 cmOMP

-4 -3 -2 -1 0 1 2 3 4x 105

10-4

10-3

10-2

10-1

100

f i(v)

V [m/s]

OMP

SE 0.1 m

Rate coefficients vs differential CS

OMP

10 cm

SE

The VDFs are strongly(!)

non-Maxwellian during the

ELMs


0 0.01 0.02 0.030

2

4

6

x 1018

x [m]

n [

m-3

]

H2

H H+2

e

H+

Density profiles from the divertor plasma

simulation. Serial PIC/MC code with ~100

of different A&M processes.

Full kinetic models

Massively parallel codes

(such as BIT-N) are able

to simulate few of different

particle species (including

metastables) with

thousands of A&M

processes.


For (kinetic) modelers collection of the appropriate

A&M&S data is the most complicated task!

10-2

10-1

100

101

102

103

10-1

100

101

102

E [eV]

PhelpsJanev

Cross-sections for H2+ + H2 charge-exchange

collision from different sources.


0 100 200 300 4000

20

40

60

80

100

qod

[MW

/m2 ]

e+D+

D

t [µs]0 100 200 300 400

0

20

40

60

80

100

120

140

qod

[MW

/m2 ]

t [µs]

e+D+

D

Power loads to the outer divertor during 0.15 MJ type-I ELM at JET #74380.

a) Constant recycling coefficient RD= 0.99;

b) Energy-dependant recycling coefficient RD(E).

a) b)

Sensitivity of simulation results to the A&M data


EFDA Task Force ITM

Task AMNS

Collection and verification of the Molecular data

Implementation into the corresponding AMNS data structure

in a standardized way

Support of different codes in implementation of

corresponding routines for accessing AMNS data

Status: data structure is ready for implementation of molecular

rate coefficients and differential CS of practically any complexity.

There is a possibility to update the data structure for metastables.


Molecular processes represent important part of predictive

plasma edge modeling

While data for rate coefficients are available, the corresponding

differential CS are hard to find

There is no systematic approach to metastables. How to include

them into the plasma edge models?

Conclusions

Independently of the complexity and format of the provided

validated molecular data, it will be used by us (i.e. modelers)!


Filaments of small and large ELMs at MAST (UK)

63.5 63.55 63.6 63.65 63.70

10

20

30

40

50

qdi

v [M

W/m

2 ]t [s]

10-100 ms

0.1-1 ms

ELMs simulations

D. Tskhakaya ADAC meeting, Cadarache 24.9.2012 18/16D. Tskhakaya PWI TF, JET Culham, 13-15 July 2011

Differential cross-sections

e + H = 2e + H+

,/,/

,2/sin11ln4

1

,1

ln1

11

1

1,

cos,cos,,

00

2

3

0322

0

3

EEEE

E

E

Ed

d

b

EE

aEE

dE

d

Ed

dE

d

dEE

dE

d

dddE

d

sspp

ion

ii

s

ip

spsspspsp

s

ion

ppp

ionss

s

ionsp

s

ion

pss

ion

10-3

10-2

10-1

100

0

0.5

1

1.5

2

2.5

BIT1 Krstic 1998

Angular differential cross sections

Documents

D. Tskhakaya ADAC meeting, Cadarache 24.9.2012 1/16 Molecular Data in Tokamak edge Modelling D. Tskhakaya Association EURATOM-ÖAW, University of Innsbruck,