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Plasma Visualization Diagnostics for KSTAR: ECEI and MIR. C.W. Domier, N.C. Luhmann, Jr. University of California at Davis FY09 US-KSTAR Collaboration Workshop April 15-16, 2009 – San Diego, CA. UC DAVIS P LASMA D IAGNOSTICS G ROUP. Outline. Introduction and Overview

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Plasma visualization diagnostics for kstar ecei and mir
Plasma Visualization Diagnostics for KSTAR: ECEI and MIR

C.W. Domier, N.C. Luhmann, Jr.University of California at Davis

FY09 US-KSTAR Collaboration WorkshopApril 15-16, 2009 – San Diego, CA

UC DAVIS

PLASMA

DIAGNOSTICS

GROUP


Outline
Outline

  • Introduction and Overview

  • Diagnostic Principles

    • Te Measurements via ECEI

    • ne Measurements via MIR and MDIR

  • Experience on Previous and Current Systems

  • Ongoing Development Activities

  • Low Field (~2 T) and High Field (3-3.5 T) Conceptual Designs

  • Diagnostic Development Plan


Outline1
Outline

  • Introduction and Overview

  • Diagnostic Principles

    • Te Measurements via ECEI

    • ne Measurements via MIR and MDIR

  • Experience on Previous and Current Systems

  • Ongoing Development Activities

  • Low Field (~2 T) and High Field (3-3.5 T) Conceptual Designs

  • Diagnostic Development Plan


Introduction and motivation
Introduction and Motivation

  • A unique window of opportunity exists on KSTAR for fundamental understanding of MHD and turbulence not possible with ITER and future burning plasma experiments

    • Excellent port access

    • Advances in 3-D simulation capability

    • Advances in imaging diagnostics capability

  • 2-D plasma microwave imaging tools

    • Electron Cyclotron Emission Imaging (ECEI)

    • Microwave Imaging Reflectometry(MIR)

    • Microwave Doppler Imaging Reflectometry (MDIR)


Outline2
Outline

  • Introduction and Overview

  • Diagnostic Principles

    • Te Measurements via ECEI

    • ne Measurements via MIR and MDIR

  • Experience on Previous and Current Systems

  • Ongoing Development Activities

  • Low Field (~2 T) and High Field (3-3.5 T) Conceptual Designs

  • Diagnostic Development Plan


2 d ece imaging ecei
2-D ECE Imaging (ECEI)

fce

  • In conventional 1-D ECE radiometry, a single antenna receives all frequencies. In ECEI, a vertically aligned antenna/ mixer array is employed as the receiver.

  • Advantages: high spatialand temporal resolution,2-D correlation.

  • Real time 2-D imaging using wideband IF electronics and single sideband detection.

    • 16×8=128 channels on ASDEX-UG

    • 20×16=320 channels onDIII-D

    • 24×32=768 channels envisaged for KSTAR

R

fce

R


Ecei system overview textor
ECEI System Overview – TEXTOR

LO

Antennas

LO1

Plasma

IF Amps

Optics

Detectors

Baluns

ADCs

Mixers

Preamps

Filters

VideoAmps

Power Divider

LOn

Notch Filter

Dichroic Plate

Mixers


Imaging fluctuation reflectometry
Imaging Fluctuation Reflectometry

  • Microwave reflections from plasma cutoffs contain information on density fluctuations near the cutoff layer

  • 1-D fluctuations: simple mirror-like interpretation

  • 2-D fluctuations: the received signal is corrupted by interference from multiple reflected waves

  • Imaging can restore phase fronts!

1-D fluctuations

2-D fluctuations


Microwave imaging reflectometry mir
Microwave Imaging Reflectometry (MIR)

  • Probing beam illuminates extended region of cutoff layer

  • Beam curvature matched (toroidal and poloidal) to that of the cutoff surface

  • Cutoff layer imaged onto array of detectors (3 elements shown), eliminating interference effects

  • Detection system shares the same plasma-facing optics


Mir system overview textor
MIR System Overview - TEXTOR

MIR Array

LOSource

Toriodal Mirror

Plasma

Beam Splitter

Illumination Source

MIR Electronics

Window

Poloidal Mirror

Mixer

I-Q Mixer

IF Amp

DACs

Antenna

Filters

Optics

Plasma

Video Amps

LO


M icrowave d oppler i maging r eflectometry
Microwave Doppler Imaging Reflectometry

  • Off-axis probing beam is scattered by Doppler rotation of fluctuations near the cutoff layer

  • Optics angularly resolve the reflected/scattered waves onto imaging array

Ray tracing of Doppler reflectometry system on Tore-Supra


Comparison between mir and mdir
Comparison Between MIR and MDIR

MIR

  • Common features

    • Planar imaging array

    • Large aperture optics

    • Multiple frequencies to probe multiple cutoff layers

  • Major differences

    • MDIR illumination beamis narrower, and tilted with respect to plasma midplane

    • MDIR probes poloidal scattering angle rather than vertical position

MDIR


Outline3
Outline

  • Introduction and Overview

  • Diagnostic Principles

    • Te Measurements via ECEI

    • ne Measurements via MIR and MDIR

  • Experience on Previous and Current Systems

  • Ongoing Development Activities

  • Low Field (~2 T) and High Field (3-3.5 T) Conceptual Designs

  • Diagnostic Development Plan


Single array ecei on textor
Single Array ECEI on TEXTOR

Single array implementation with 16×8 Te image resolution


Textor study of sawtooth oscillation
TEXTOR Study of “Sawtooth Oscillation”

ECEI demonstrated “random 3-D reconnection zone,” in which the reconnection zone has been observed to occur everywhere (including high field side, see video left)


Single array ecei on asdex ug
Single Array ECEI on ASDEX-UG

TEXTOR system transferred to ASDEX-UG in Jan. 2009, and will begin operation in May 2009


Dual array ecei on diii d
Dual Array ECEI on DIII-D

Horizontal and vertical zoom control with full remote capability

Two array system, each 20×8 channels expandable to 20×24

Installation in Sept. 2009, with first results in Oct. 2009

1.3 m

Narrow zoom Narrow spacing

27 cm


Dual array ecei on diii d1
Dual Array ECEI on DIII-D

Horizontal and vertical zoom control with full remote capability

Two array system, each 20×8 channels expandable to 20×24

Installation in Sept. 2009, with first results in Oct. 2009

1.3 m

Wide zoom Wide spacing

55 cm


Dual array ecei on diii d2
Dual Array ECEI on DIII-D

Horizontal and vertical zoom control with full remote capability

Two array system, each 20×8 channels expandable to 20×24

Installation in Sept. 2009, with first results in Oct. 2009

1.3 m

Wide zoom Wide spacing

55 cm


Outline4
Outline

  • Introduction and Overview

  • Diagnostic Principles

    • Te Measurements via ECEI

    • ne Measurements via MIR and MDIR

  • Experience on Previous and Current Systems

  • Ongoing Development Activities

  • Low Field (~2 T) and High Field (3-3.5 T) Conceptual Designs

  • Diagnostic Development Plan


Ongoing development activities
Ongoing Development Activities

  • Mini-lens imaging array concept and vertical zoom optics

  • Horizontal zoom ECEI electronics and frequency extenders

  • Quasi-optical notch filters

  • High frequency imaging antennas

  • Multi-frequency MIR sources


Mini lens array configuration
Mini-Lens Array Configuration

Advantages

Elliptical substrate lens optimizes coupling and reduces sidelobes

Eliminates off-axis aberrations

Uses front side LO pumping for enhanced coupling, increased sensitivity and wide bandwidth (octave) operation

Mini-Lenses

Antennas

Beam Splitter

LO Beam


New mini lens ecei system optics
New Mini-Lens ECEI System Optics

Notch Filters (3)

LO Source

ECEI Array

Beamsplitter

Focal Plane Translation Lens

Zoom Control Lenses


New vertical zoom optics
New Vertical Zoom Optics

Narrow Zoom

Shot 107809

Wide Zoom

Shot 107808

Te images courtesy of Prof. T. Munsat at the University of Colorado


New horizontal zoom electronics

Mixer

VCO

VCO

3.4 GHz

2.5 GHz

LP Filter

4.0 GHz

3.4 GHz

4.3 GHz

4.6 GHz

Digital

Attenuator

5.2 GHz

5.2 GHz

Power Divider

6.1 GHz

5.8 GHz

HP Filter

7.0 GHz

6.4 GHz

7.9 GHz

7.0 GHz

8.8 GHz

7.6 GHz

New Horizontal Zoom Electronics

Horizontal spacing and spot size can now be independently and remotely-controlled


Multiple modules for increased coverage
Multiple Modules for Increased Coverage

Standardized modules can be ganged together to extend RF coverage

  • Two modules provide16 GHz coverage

  • Three modules provide24.5 GHz coverage


New stackable notch filters
New “Stackable” Notch Filters

  • Highly collimated mini-lens beams permit significantly improved ECRH shielding

    • Relaxed angular requirements (≤ 8°)

    • Stack up to 3 notch filters in series

  • 140 GHz filter stack installed on TEXTOR (single filter results shown below)

  • 170 GHz filter stack under development for KSTAR

Quasi-Optical Notch Filters

Quasi-Optical Notch Filters


Antennas mixers for high field ecei
Antennas/Mixers for High-Field ECEI

fLO

fLO≈ ½fRF

  • Two approaches under investigation to realize imaging antennas for ECEI on KSTAR under high-field (3-3.5 T) conditions

  • Fundamental mixers require high frequency (150-220 GHz) sources with >40 mW output power  difficult to obtain!

  • 2nd harmonic mixers have 2-3 dB worse conversion losses, but can use lower frequency (75-110 GHz) sources  readily available!

fIF = fRF - fLO

fRF

fIF = fRF - 2fLO

fRF

Fundamental

Mixer

2nd Harmonic

Mixer


Postech collaboration prof hyeon park on mir characterization

TEXTOR MIR system now set up at POSTECH for detailed laboratory measurements and characterization

POSTECH Collaboration (Prof. Hyeon Park) on MIR Characterization


Pppl collaboration dr gerrit kramer on mir modelling

2-D simulations of microwaves reflected from a circular plasma, with an illumination beam curvature-matched to the plasma

PPPL Collaboration (Dr. Gerrit Kramer) on MIR Modelling


Kyungpook national university collaboration prof kangwook kim on mir illumination sources
Kyungpook National University Collaboration (Prof. Kangwook Kim) on MIR Illumination Sources

Schematic illustrating how a simultaneous “comb” of illumination frequencies can probe multiple cutoff layers, as each frequency reflects from a distinct cutoff layer



Outline5
Outline Kim) on MIR Illumination Sources

  • Introduction and Overview

  • Diagnostic Principles

    • Te Measurements via ECEI

    • ne Measurements via MIR and MDIR

  • Experience on Previous and Current Systems

  • Ongoing Development Activities

  • Low Field (~2 T) and High Field (3-3.5 T) Conceptual Designs

  • Diagnostic Development Plan


Kstar diagnostic layout
KSTAR Diagnostic Layout Kim) on MIR Illumination Sources


Ecei configuration 2t
ECEI Configuration: ~2T Kim) on MIR Illumination Sources

Focal lenses

  • Low field (~2 T) design for ECEI only

  • High field side (HFS) and low field side (LFS) systems share the same zoom optics (inside cassette)

  • Two array configuration per port, each generating 24(v)×8(h) Te images expandable to 24×24 images

Zoom lenses

HFS array

Mirror

Toroidal

lenses

Plasma

Cassette

Vacuum

window

LFS array

Beam splitter


Ecei on kstar at 2 0 t
ECEI on KSTAR at 2.0 T Kim) on MIR Illumination Sources

100 cm

33 cm

High Field Side

Low Field Side


Ecei on kstar at 2 0 t1
ECEI on KSTAR at 2.0 T Kim) on MIR Illumination Sources

100 cm

33 cm

High Field Side

Low Field Side


Ecei on kstar at 2 0 t2
ECEI on KSTAR at 2.0 T Kim) on MIR Illumination Sources

100 cm

51 cm

High Field Side

Low Field Side


Ecei mir configuration 3 3 5 t
ECEI/MIR Configuration: 3-3.5 T Kim) on MIR Illumination Sources

Focal lenses

Zoom lenses

MIR array

MIR Source

  • High field design for simultaneous ECEI and MIR/MDIR

  • Two array ECEI configuration, each generating 24×8 Te images expandable to 24×24 images

  • Single array MIR/MDIR configuration with a 16 element array and up to 8 simultaneous frequencies/cutoff layers

  • Decision to implement MIR or MDIR (or both) dependent upon results from joint POSTECH and PPPL study into MIR physics

Beamsplitter

Toroidal

lenses

Plasma

Cassette

Vacuum

window

ECEI array

Dichroic Plate


Ecei at high field 3 3 5 t
ECEI at High Field (3-3.5 T) Kim) on MIR Illumination Sources

100 cm

51 cm

High Field Side

Low Field Side


Mir mdir at high field 3 3 5 t
MIR/MDIR at High Field (3-3.5 T) Kim) on MIR Illumination Sources

100 cm

20 cm


Outline6
Outline Kim) on MIR Illumination Sources

  • Introduction and Overview

  • Diagnostic Principles

    • Te Measurements via ECEI

    • ne Measurements via MIR and MDIR

  • Experience on Previous and Current Systems

  • Ongoing Development Activities

  • Low Field (~2 T) and High Field (3-3.5 T) Conceptual Designs

  • Diagnostic Development Plan


Diagnostic development plan
Diagnostic Development Plan Kim) on MIR Illumination Sources

FY2009

  • Design multi-array low field (~2 T) ECEI system

  • Develop multi-frequency source technology for MIR/MDIR (collaboration with Kyungpook National University)

  • Fabricate and test high performance 170 GHz notch filters

    FY2010

  • Fabricate and characterize multi-array low-field ECEI system

  • Install multi-array low-field ECEI system on KSTAR

  • Fabricate and test prototype high-field (3.0-3.5 T) ECEI antennas

  • POSTECH and PPPL to complete MIR system tests; results to be used to design optimum MIR and/or MDIR optical configuration

    FY2011

  • Operate and maintain low-field ECEI system on KSTAR

  • Design high field (3-3.5 T) simultaneous ECEI and MIR/MDIR system


Thank you for your attention
Thank you for your attention Kim) on MIR Illumination Sources


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