Abstract: A helium plasma characterised by an emission spectrum dominated by the 1s3p 1P1 to 1s2 1S0 501.5 nm transmission line, and a pressure less than 5×10?3 mbar. Methods and apparatus for igniting the plasma, and for using the plasma for pre-ionisation and glow discharge cleaning are also disclosed.

Abstract: A tokamak comprising a toroidal containment vessel and a plasma initiation system. The toroidal containment vessel is configured to contain a plasma. The plasma initiation system comprises upper and lower poloidal field, PF, coil sets. Each PF coil set comprises at least one inner PF coil located outside of the containment vessel, an outer PF coil located inside the containment vessel, and shielding located between the outer PF coil and a location of the plasma during operation of the tokamak and configured to protect the outer PF coil from heat emitted by the plasma. The inner and outer PF coils are configured so as to form a PF null within the containment vessel between the inner and outer PF coils, such that the upper and lower PF coil pairs are operable to initiate a plasma in the containment vessel via double null merging.

Abstract: A tokamak comprising a toroidal containment vessel and a plasma initiation system. The toroidal containment vessel is configured to contain a plasma. The plasma initiation system comprises upper and lower poloidal field, PF, coil sets. Each PF coil set comprises at least one inner PF coil located outside of the containment vessel, an outer PF coil located inside the containment vessel, and shielding located between the outer PF coil and a location of the plasma during operation of the tokamak and configured to protect the outer PF coil from heat emitted by the plasma. The inner and outer PF coils are configured so as to form a PF null within the containment vessel between the inner and outer PF coils, such that the upper and lower PF coil pairs are operable to initiate a plasma in the containment vessel via double null merging.

Abstract: A toroidal field coil for generating a toroidal magnetic field in a nuclear fusion reactor comprising a toroidal plasma chamber having a central column. The toroidal field coil comprises a portion passing through the central column. The portion passing through the central chamber comprises: ?a low temperature superconductor, LTS, layer (21) formed from LTS; ?a high temperature superconductor, HTS, layer (22) formed from HTS and located radially outward of the LTS layer. ?a non-superconducting conductive layer (23) formed from electrically conducting, non-superconducting material and located radially outward of the HTS and LTS layers.

Abstract: A toroidal field coil for generating a toroidal magnetic field in a nuclear fusion reactor includes a toroidal plasma chamber having a central column. The toroidal field coil has a plurality of windings configured to pass through the central column and around the outside of the plasma chamber. Each winding includes a cable having a plurality of stacked high temperature superconductor (HTS) tapes, each HTS tape including one or more layers of a high temperature superconductor material. With the toroidal field coil in place in the reactor, a face of each HTS tape is substantially perpendicular to a direction of maximal neutron flux during reactor operation as the cable passes through the center column.

Abstract: An efficient compact nuclear fusion reactor for use as a neutron source or energy source is described. The reactor comprises a toroidal plasma chamber and a plasma confinement system arranged to generate a magnetic field for confining a plasma in the chamber. The plasma confinement system is configured so that a major radius of the confined plasma is 1.5 m or less. The reactor is constructed using high temperature superconducting toroidal magnets, which may be operated at low temperature (77K or lower) to provide enhanced performance. The toroidal magnetic field can be increased to 5 T or more giving significant increases in fusion output, so that neutron output is very efficient and the reactor can produce a net output of energy.

Abstract: A toroidal field coil for generating a toroidal magnetic field in a nuclear fusion reactor comprising a toroidal plasma chamber having a central column. The toroidal field coil comprises a portion passing through the central column. The portion passing through the central chamber comprises: a low temperature superconductor, LTS, layer (21) formed from LTS; a high temperature superconductor, HTS, layer (22) formed from HTS and located radially outward of the LTS layer. a non-superconducting conductive layer (23) formed from electrically conducting, non-superconducting material and located radially outward of the HTS and LTS layers.

Abstract: An efficient compact nuclear fusion reactor for use as a neutron source or energy source includes a toroidal plasma chamber and a plasma confinement system arranged to generate a magnetic field for confining a plasma in the chamber, where the plasma confinement system is configured so that a major radius of the confined plasma is 1.5 m or less and the toroidal magnetic field is operated 5 T or less and the plasma current is 5 MA or less, yet a-particles generated are confined in the plasma.

Abstract: Disclosed herein is a toroidal field coil for generating a toroidal magnetic field in a nuclear fusion reactor comprising toroidal plasma chamber having a central column, the toroidal field coil comprising a plurality of windings passing through the central column and around the outside of the plasma chamber. Each winding includes a cable comprising a plurality of stacked HTS tapes, each HTS tape including one or more layers of a high temperature superconductor material.

Abstract: An efficient compact nuclear fusion reactor for use as a neutron source or energy source is described. The reactor comprises a toroidal plasma chamber and a plasma confinement system arranged to generate a magnetic field for confining a plasma in the chamber. The plasma confinement system is configured so that a major radius of the confined plasma is 1.5 m or less. The reactor is constructed using high temperature superconducting toroidal magnets, which may be operated at low temperature (77K or lower) to provide enhanced performance. The toroidal magnetic field can be increased to 5 T or more giving significant increases in fusion output, so that neutron output is very efficient and the reactor can produce a net output of energy.

Abstract: A compact nuclear fusion reactor for use as a neutron source is described. The reactor comprises a toroidal plasma chamber (34) and a plasma confinement system (31) arranged to generate a magnetic field for confining a plasma in the plasma chamber (34). The plasma confinement system (31) is configured so that a major radius of the confined plasma is 0.75 m or less. The reactor is configure to operate with a plasma current of 2 MA or less. The magnetic field includes a toroidal component of 5 T or less. Despite these low values, the reactor can generate a neutron output of 1 MW or more.