Joint European Torus - Machine Information

Machine Information

• Weight of the vacuum vessel: 100 tonnes
• Weight of the toroidal field coils: 384 tonnes
• Weight of the iron core: 2800 tonnes
• Wall material: Entirely Beryllium save Tungsten 'exhaust'
• Plasma major radius: 2.96 m
• Plasma minor radius: 2.10 m (vertical), 1.25 m (horizontal)
• Flat top pulse length: 20–60 s
• Toroidal magnetic field (on plasma axis): 3.45 T
• Plasma current: 3.2 MA (circular plasma), 4.8 MA (D-shape plasma)
• Lifetime of the plasma: 5–30 s
• Auxiliary heating:
  • Neutral beam injection heating ≤23 MW
  • Radio frequency heating ≤15 MW
• Major diagnostics:
  • Visible/infrared video cameras
  • Numerous magnetic coils – provide magnetic field, current and energy measurements
  • Thomson scattering spectroscopy – provides electron temperature and electron density profiles of the plasma
  • Charge exchange spectroscopy – provides impurity ion temperature, density and rotation profiles
  • Interferometers – measure line integrated plasma density
  • Electron cyclotron emission antennas – fast, high resolution electron temperature profiles
  • Visible/UV/X-ray spectrometers – temperatures and densities
  • Neutron diagnostics:
    • Neutron counting: Number of neutrons leaving the plasma relates directly to the fusion power.
    • Neutron spectroscopy – Neutron energy relates to the ion velocity distribution and hence the fuel reactivity.
  • Bolometers – energy loss from the plasma
  • Various material probes – inserted into the plasma to take direct measurements of flow rates and temperatures
  • Soft X-ray cameras to examine MHD properties of plasmas
  • Time resolved neutron yield monitor
  • Hard X-ray monitors
  • Electron Cyclotron Emission Spatial Scanners