Current status of H-mode/pedestal related experiments in JT-60U

14th meeting of the ITPA-TG on Pedestal&Edge Physics Group, General Atomics, April 29-May 2, 2008

N. Oyama and the JT-60 Team

JAEA Naka

Important notice

Our Director General (Dr. Tsunematsu) of Naka Fusion institute has officially announced that JAEA decided to shut down JT-60U in August in 2008.

The physics experiments will be 11 weeks (43 days) from May to August. So, the machine time is quite limited. However, we would like to promote inter-machine experiments to contribute ITPA and ITER activity as well as our original experiments.

Your direct participation in inter-machine experiments are very welcome. (Last chance!)

Experimental schedule

Current plan of H-mode & pedestal related experiments

New diagnostics (fast CXRS)

SpecificationsSpatial resolution (spot size):

~5 cm (Toroidal, 30ch)

~0.5 cm (Poloidal, 30ch)

Time resolution: 2.5-5 ms

(Previously 50 ms)

Co-rotating plasmaIp/BT = 1.66MA/3.2TPNBI ~ 6.4MWfELM ~ 18Hz

A

B

8.94s

New diagnostics (Li-beam probe)Purpose

Density and density fluctuation profiles

Ti and Vp profiles as CXRS

Current profile by Zeeman polarimetry

Specifications Spatial resolution (dR): <10 mm Time resolution for j(r): 1-10 ms Frequency range for density fluctuati

on: <500kHz Beam duration: <60 s

Current status Development of beam was finished. Beam axis alignment and adjustment

of etalon filter are on going. Density profile measurement will be

available from MayA. Kojima, submitted to RSI

Objectives of pedestal research

Making use of new edge diagnostics,following pedestal research will be conducted.

Pedestal structure and H-mode confinement Effect of TF ripple, rotation, neutral penetration, current

profile Inter ELM transport

Dynamics and characteristics of type I ELM Precursor, affected area, recovery of transport barrier Propagation of ELM pulse in SOL and inside the top pedestal

toward ITB Physics understanding of the role of plasma rotation Edge stability including measured edge current

Small/no ELM regimes (grassy ELM and QH-mode) Physics understanding of the role of plasma rotation and e

*

Expansion of operational regime

PEP-1+3 JET/JT-60Uripple effects and rotation

In 2005-2006 campaign, combination of tangential NBI was fixed To separate rotation effect, rotation scan experiments using

JET/JT-60U similarity shape are proposed.

N. Oyama, 11th H-mode WS. Accepted for publication in JPCS.

PEP-13/17 grassy ELM experiments

e* scan (toward higher than 1) by changing edge ne

Target plasma is operated at high regime(both low and high q95 regime)

Rotation effect is also interested.

PEP-14 QH-mode experiments

DIII-D

CTR rotation

K. Burrell, APS2007 JT-60U

N. Oyama,NF45(2005)