FFS at JET/Ameigs 02-09-13

FFS at JET(Spectral fitting using FFS)

A. Meigs

FFS at JET/Ameigs 02-09-13

FFS at JET: Outline of talk

1. What is FFS?2. Balmer series D10-2 to D13-2 Fitting 3. Single Balmer D7-2 with W I and N II 4. Work needed/planned

FFS at JET/Ameigs 02-09-13

What is FFS?

Framework for Feature Synthesis (FFS)

Created by Chris Nicholas (see 2010 ADAS PhD) with A. Meigs and Allan Whiteford from an earlier start called glvoop by A. Meigs

ADAS Workshop presentations by C. Nicholas in 2008, 2009A. Meigs in 2007

Object oriented system in IDL for modular modelling, and fittingUses a Model Definition Language (MDL), Lisp-like scripting language, for creating complex models (command line for simple models also available*):

•Handles complex combination of elements that comprise a model•Loads initial parameter values, limits for fitting, fixed parameters•MDL also handles coupling of parameters

System comprised of a Model/Element/Parameter-Property hierarchy linked with a parser/executor for the MDL scripts.

Easily links with the ADAS AFG system to import ADAS special feature models(Zeeman, Motional Stark multiplet, Heavy species envelopes)See C. Nicholas thesis for a wide range of examples

Currently, limited to 1D models (extension to 2D should not be hard, just not investigated yet)

FFS at JET/Ameigs 02-09-13

FFS at JET: Class Diagram

*C. Nicholas, Thesis 2010

Available elementsLine shapes:Dirac-Delta approx (sticks)GaussianLorentzianVoigt(ian)

Broadeners:GaussianLorentz

Maths:Add (+)Scale factor

AFG:ZeemanHigh-z envelopeStark emission…

FFS at JET/Ameigs 02-09-13

Density Limit Discharge (81469) fitting Balmer spectra

ADAS/Ameigs 02-09-13

KT3 Diagnostic

Mirror Link view of the outer divertor:No fibers largest wavelength coverageof any diagnostic on JET (200nm-1200nm)

Three spectrometers with “common” LOS

LOS cover just inside tile-5 to vertical tile-8 (tile-7 is shadowed)

FFS at JET/Ameigs 02-09-13

Model of High-n Balmer Spectra

Left out in this model the extra impurity linesas they get swamped out by the Balmerlines for this pulse (have included them inless dense/recombining plasmas)

Value from fitting impurity line pre-recombining phase

FFS at JET/Ameigs 02-09-13

Fits to High-n Balmer Spectra: 81469 Density Limit Pulse

Highish density spectra fit

FFS at JET/Ameigs 02-09-13

Fits to High-n Balmer Spectra: 81469 Density Limit Pulse

Lowish density spectral fit

FFS at JET/Ameigs 02-09-13

Electron density results for 81469 from Stark Broadening

R outer strike point

R X-point

Can follow for the first time the density limit from strike point to MARFE formation at the X-point

FFS at JET/Ameigs 02-09-13

Simple model of W I/D 7-2/N II spectra

(model kt3b_wv4020_simple2 (+ (+ (voigtian d72) (gaussian w1a) (gaussian n2f) (gaussian n2j) (gaussian u0) (gaussian u1) (gaussian u2) (gaussian u3) ) (background-linear bkg) )) (dummy d )(setval bkg.m 0.0)(setval bkg.c 8.0e18)(setlimits bkg.c 1.0e12 1.0e21)(setval d.dens 5.0e19)(fixed bkg.m)(log d.dens)(setlimits d.dens 5.0e18 1.0d21)

(setval d72.pos 396.899) 7->2 396.899 nist(setval w1a.pos 400.87506)(setval n2f.pos 399.5)(setval n2j.pos 395.585)

(couple d72.fwhml (* (/ (* 0.00139 (^ (* d72.pos 1e-9) 2) (^ d.dens (/ 2.0 3.0)) (- (^ 7.0 2)(^ 2.0 2))) 1.8836516e09) 1e9))

FFS at JET/Ameigs 02-09-13

Rest of the Simple model of W I/D 7-2/N II spectra

(setlimits d72.pos 396.6 397.3)(setlimits w1a.pos 400.7 400.9)(setlimits n2f.pos 399.4 399.6)(setlimits n2j.pos 395.3 395.7)(s etlimits he1a.pos 402.4 402.8)

(setval n2f.fwhm 0.1)(setlimits n2f.fwhm 0.01 0.4)

(s etval w1a.fwhm 0.1)(s etlimits w1a.fwhm 0.01 0.4)

(couple d72.fwhmg = n2f.fwhm)(couple n2j.fwhm = n2f.fwhm)(couple w1a.fwhm = n2f.fwhm)(c ouple he1a.fwhm = n2f.fwhm)

(setval d72.area 3.e18)(setval w1a.area 8.e15)(setval n2f.area 4.e16)(setval n2j.area 1.e16)

(setlimits d72.area 0.01 9.0e23)(setlimits w1a.area 0.01 5.0e20)(setlimits n2f.area 0.01 5.0e21)(setlimits n2j.area 0.01 5.0e19)

(setval u0.pos 397.326)(setval u1.pos 398.291)(setval u2.pos 395.437)(setval u3.pos 401.389)

(setlimits u0.pos 397.0 397.6)(setlimits u1.pos 398.1 398.4)(setlimits u2.pos 395.2 395.6)(setlimits u3.pos 401.2 401.5)

(setval u0.area 1.0e16)(setval u1.area 9.0e15)(setval u2.area 6.0e15)(setval u3.area 3.0e15)

(setlimits u0.area 0.01 5.0e17)(setlimits u1.area 0.01 5.0e17)(setlimits u2.area 0.01 5.0e17)(setlimits u3.area 0.01 5.0e17)

(couple u0.fwhm = n2f.fwhm)(couple u1.fwhm = n2f.fwhm)(couple u2.fwhm = n2f.fwhm)(couple u3.fwhm = n2f.fwhm)

FFS at JET/Ameigs 02-09-13

Low electron density pulse (81474) example fit

D7-2

u0 u1

n2f (N II)

w1a (W I)u2 n2j

u3

FFS at JET/Ameigs 02-09-13

Higher electron density pulse (81478) example fit

D7-2

u0 u1

n2f (N II)

w1a (W I)u2 n2j

u3

FFS at JET/Ameigs 02-09-13

Comparison High vs D7-2 electron densities

High-n balmer fit (81476) D7-2 fit (81478)

Able to fit D7-2 early (hence expanded time range)

Shapes very similarMagnitudes another matter

FFS at JET/Ameigs 02-09-13

2D comparison for two times

Pre-detachment (t=8.94s) Post-detachment (t=15.7s)

High-n ne (81476)High-n ne (81476)

D7-2 ne (81478) D7-2 ne (81478)

Caveats/Problems:1) Two different pulses (even though 81478 meant to be a repeat of 81476)2) N II reference may not be good for higher densities (see next page)

Really need measurement in same pulse (pretty sure I have it at some point)

FFS at JET/Ameigs 02-09-13

Simple model of W I/D 7-2/N II spectra

Problems with this fit (preliminary):1) Using the N II 399.5nm line as fwhm reference for high density plasmas can be problem as it’s intensity decreases as the plasma gets colder and denser(same holds true for tungsten)

Will need to fit the reference early and use that width (as I did for the High-n Balmer series reference)

FFS at JET/Ameigs 02-09-13

Work to be done in FFS

1. Additional elements coded:Multiply element (Gaussian x Gaussian) Bremsstrahlung model (ffs/afg)Re-implement interface to PPP (revive collaboration with Marseille)

2. Implement Model containing another model 3. FFS (probably ffs_model) handling blind areas (areas of independent axis where you

want no weighting so that it does not affect chi^2, i.e. allow removal of nuissance lines) 4. Revive tree-view of models

(ffs_model_browser__define and ffs_tree__define, presented by C. Nicholas in 2008-09):

Aim to get usable model editor Needs limits display Needs coupling tab/display Write back to a model file

Needs ability to move elements up/down tree... Enforce unique element names! Enforce non-zero values/limits... Gui to model file and gui to model changes (improve model to parser

communication) Finally(1), a tutorial on using FFS/AFG to be given at the ADAS-EU workshop at JET

end of September/Early October Finally(2), we need new users and developers!

FFS at JET/Ameigs 02-09-13

Simple model of W I/D 7-2/N II spectra