NBI System | Negative-ion based NBI for JT-60U

Negative-ion based NBI for JT-60U

Picture of the N-NBI installed in JT-60 torus hall

Picture and performance of ion source

Negative Ion Sources for JT-60U

Beam energy : 500keV
Current : 22A/D-
Multi-cusp type with Cs
3tage- electro/static accel
Extaction area : 45 × 110 cm²

Beamline

N-NBI Beamline for JT-60U

Achieved values of negative ion beams with N-NBI

A negative ion current of 18.5A/H- at 360keV, 14.3A/D- at 380keV has been obtained
Deuterium : 14.3A at 380keV (5.4MW) (~9mA/cm²)
Hydrogen : 18.5A at 360kV (6.6MW) (~11mA/cm²)

Progress of injection power

A neutral beam power of 4.1MW at 360keV has injected into JT-60U plasma
Deuterium beam : 3.6MW at 350keV
Hydrogen beam : 4.1MW at 360keV

Neutralization efficiency of H^-, D^-

Beam energy vs neutralization efficiency
Neutralization efficiency has been confirmed to be 60% in a beam energy range of 250~380keV as predicted theoretically.