The Design of KSTAR FM reflectometer

Seong-Heon SeoNational Fusion Research

Institute (NFRI)

Contents

• KSTAR

• Design

• Schedule

KSTAR Tokamak

R=1.8 m, a = 0.5 mPF and TF (BT=3.5 T) Coils = Nb3SnIP = 2 MA, 5 min

Bad accessibility

First Plasma in KSTAR

• BT = 1.5 T• 2nd Harmonic ECH preionization (84 GHz, 300 kW)• Plasma current ~ 100 kA, 0.7 s

• Magnetic Diagnostics• Interferometer (1 ch)• ECE (8 ch)• Hα, Filter Scope• CCD Camera (1 kHz)

2nd Campaign (2009. 9)

• BT = 3.0 T• Plasma current ~ 300 kA, 2 s• Fundamental Harmonic ECH preionization (84 GHz, 500 kW)

• Magnetic Diagnostics• Reflectometer (2 ch, Q and V Band)• ECE (32 ch)• Bolometer• X-ray Crystal Spectroscopy (XCS)

Operation Parameter

New Diagnostics

Frequency Selection

Plasma typeLow field

High fieldCase I Case II

n0 (x1014 cm-3) 0.2 0.71 1.68B0 (T) 1.5 3.5 3.5

fx_cfce

2fce

fpe

Plasma type

Low field High fieldCase I Case II

Wave mode O X O X O XFrequency range of probing

signals [GHz]0-33 33-66 0-75 75-150 0-118 77-153

Max. accessible position r of cutoff layer (cm)

217 183 180 143 180 212

Q and V Band Reflectometer

Q Band (33-50 GHz)

Mixer, MQ-USpaceK Labs

Low pass filterLPF1-43-9SpaceK Labs25 dB

Low pass filterFLP-22-R0000Militech40 dB

TransitionTWT-28-R22R0Militech

Frequency multiplierAQ-4XW-10SpaceK Labs

V Band (50-75 GHz)Mixer, MV-USpaceK Labs

Low pass filterLPF1-62-9SpaceK Labs25 dB

Low pass filterFLP-15-R0000Militech40 dB

TransitionTWT-28-R15R0Militech

Frequency multiplierAMC-15-RFH00Militech

Antenna design

Antenna design

Diagnostics on G-port

1. Interferometer (2008)--> FIR on H-port

2. Reflectometer (2009)

3. MIR (2012) POSTEC TEXTOR 5 frequencies

Interferometer in G-port

Antenna of Interferometer

G Port

Antenna design

Engineering Design

DETAIL VIEW

DETAIL VIEW

DETAIL VIEW

Frequency Selection

Plasma typeLow field

High fieldCase I Case II

n0 (x1014 cm-3) 0.2 0.71 1.68B0 (T) 1.5 3.5 3.5

fx_cfce

2fce

fpe

Plasma type

Low field High fieldCase I Case II

Wave mode O X O X O XFrequency range of probing

signals [GHz]0-33 33-66 0-75 75-150 0-118 77-153

Max. accessible position r of cutoff layer (cm)

217 183 180 143 180 212

W and D Band (Bt = 3.5 T)

Too expensive

Summary and Schedule

2nd campaign:

- Q (33-50 GHz) and V (50-75 GHz) Band in X-mode- BT = 1.5 T

3rd campaign:

- BT = 3.0 T- W Band (75-110 GHz) in X-mode

D Band Q and V Band in O-mode

Square waveguide+ Twister

Cross Polarization