Method and apparatus for the formation of a spheromak plasma

Claim 1

An apparatus for producing and confining a spheromak plasma, comprising: a generally spheroidal vacuum vessel having a major axis and an equatorial midplane; equilibrium field coil means for producing an equilibrium magnetic field directed primarily along the major axis; a ring core disposed within said vacuum vessel symmetrically with respect to said major axis and said equatorial midplane, and having a minor axis in said equatorial plane surrounding said major axis, a major radius and a minor radius, said ring core including a toroidal flux coil wound about said minor axis and a separate poloidal flux coil and being supported within said vacuum vessel by a plurality of ring supports, said ring supports housing conductors for supplying current to said poloidal and toroidal flux coils; means for energizing said equilibrium field coils at a time t 1 to create a first poloidal magnetic field within said vacuum vessel; means for energizing said poloidal flux coil at a time t 2 >t 1 to create a second poloidal magnetic field within said vacuum vessel, said first and second poloidal fields being superposed to form a composite poloidal field whose strength is greater on a radially exterior major radius side of said ring core, than on a radially interior major radius side of said ring core; means for energizing said toroidal flux coil at a time t 3 >t 1 for initiating a plasma discharge within said vacuum vessel outside said toroidal flux coil, said ring core and said equilibrium field coils being operable to cause said plasma to become expanded and distended toward said major axis; and means for pinching off a portion of said distended plasma, whereby a detached spheromak plasma concentric with, and having a major radius less than the major radius of, said ring core is produced.

Claim 2

An apparatus for producing and confining a spheromak plasma, comprising: a generally spheroidal vacuum vessel having a major axis and an equatorial midplane; equilibrium field coil means for producing an equilibrium magnetic field directed primarily along the major axis; a ring core disposed within said vacuum vessel symmetrically with respect to said major axis and said equatorial midplane, and having a minor axis in said equatorial plane surrounding said major axis, a major radius and a minor radius, said ring core including a toroidal flux coil wound about said minor axis and a separate poloidal flux coil and being supported within said vacuum vessel by a plurality of ring supports, said ring supports housing conductors for supplying current to said poloidal and toroidal flux coils; means for energizing said equilibrium field coils at a time t 1 to create a first poloidal magnetic field within said vacuum vessel; means for energizing said poloidal flux coil at a time t 2 >t 1 to create a second poloidal magnetic field within said vacuum vessel, said first and second poloidal fields being superposed to form a composite poloidal field whose strength is greater on a radially exterior major radius side of said ring core, than on a radially interior major radius side of said ring core; means for energizing said toroidal flux coil at a time t 3 >t 1 for initiating a plasma discharge within said vacuum vessel outside said toroidal flux coil, said ring core and said equilibrium field coils being operable to cause said plasma to become expanded and distended toward said major axis; and means for pinching off a portion of said distended plasma, whereby a detached spheromak plasma concentric with, and having a major radius less than the major radius of, said ring core is produced.

Claim 3

An apparatus for producing and confining a spheromak plasma, comprising: a vacuum chamber having a major axis and an equatorial midplane, first coil means for producing a first poloidal magnetic field in said vacuum chamber at a time t 1 , a ring core having a minor axis surrounding said major axis disposed symmetrically within said vacuum chamber with respect to said equatorial plane and said major axis, said ring core including: second coil means for producing a second poloidal vacuum magnetic field in said vacuum chamber at a time t 2 >t 1 , said second poloidal vacuum magnetic field being a time-varying field; and third coil means for producing a time varying toroidal vacuum magnetic field inside said ring core at a time t 3 >t 1 , and for initiating in the presence of a gas outside said ring core a plasma discharge in said vacuum chamber outside said ring core; said first and second poloidal magnetic fields, when superposed, forming a composite poloidal magnetic field having a strength which is weaker on a radially interior major radius side of said ring core than on a radially exterior major radius side of said ring core, such that said plasma expands into the region of weaker magnetic field; and means for pinching off a portion of said expanded plasma and for causing reconnection of the magnetic field lines thereof, thereby forming a detached spheromak plasma concentric with, and having a major radius less than the major radius of, said ring core.

Claim 4

An apparatus for producing and confining a spheromak plasma, comprising: a vacuum chamber having a major axis and an equatorial midplane, first coil means for producing a first poloidal magnetic field in said vacuum chamber at a time t 1 , a ring core having a minor axis surrounding said major axis disposed symmetrically within said vacuum chamber with respect to said equatorial plane and said major axis, said ring core including: second coil means for producing a second poloidal vacuum magnetic field in said vacuum chamber at a time t 2 >t 1 , said second poloidal vacuum magnetic field being a time-varying field; and third coil means for producing a time varying toroidal vacuum magnetic field inside said ring core at a time t 3 >t 1 , and for initiating in the presence of a gas outside said ring core a plasma discharge in said vacuum chamber outside said ring core; said first and second poloidal magnetic fields, when superposed, forming a composite poloidal magnetic field having a strength which is weaker on a radially interior major radius side of said ring core than on a radially exterior major radius side of said ring core, such that said plasma expands into the region of weaker magnetic field; and means for pinching off a portion of said expanded plasma and for causing reconnection of the magnetic field lines thereof, thereby forming a detached spheromak plasma concentric with, and having a major radius less than the major radius of, said ring core.

Claim 24

A method for producing and confining a spheromak plasma, comprising: evacuating a vacuum vessel and filling said vessel with a neutral species, producing a first poloidal magnetic field by pulsing a current through a pair of toroidal equilibrium field coils, producing a second poloidal magnetic field by pulsing a current through a poloidal field generating coil of a ring core, such that said first and second poloidal magnetic fields are superimposed to form a composite poloidal field having first and second regions, the poloidal field in said second regin being stronger than the poloidal field in said first region, producing a toroidal vacuum magnetic field inside said ring core by passing a current through a toroidal field generating coil of said ring core, thereby initiating a plasma discharge in said vacuum vessel outside said ring core and causing toroidal flux to appear outside of said ring core, expanding the plasma in the direction of said first region, and pinching off a portion of said expanded plasma so as to cause poloidal magnetic field line reconnection within the pinched-off portion, thereby producing a detached spheromak plasma concentric with, and having a major radius less than the majors radius of, said ring core.

Claim 25

A method for producing and confining a spheromak plasma, comprising: evacuating a vacuum vessel and filling said vessel with a neutral species, producing a first poloidal magnetic field by pulsing a current through a pair of toroidal equilibrium field coils, producing a second poloidal magnetic field by pulsing a current through a poloidal field generating coil of a ring core, such that said first and second poloidal magnetic fields are superimposed to form a composite poloidal field having first and second regions, the poloidal field in said second regin being stronger than the poloidal field in said first region, producing a toroidal vacuum magnetic field inside said ring core by passing a current through a toroidal field generating coil of said ring core, thereby initiating a plasma discharge in said vacuum vessel outside said ring core and causing toroidal flux to appear outside of said ring core, expanding the plasma in the direction of said first region, and pinching off a portion of said expanded plasma so as to cause poloidal magnetic field line reconnection within the pinched-off portion, thereby producing a detached spheromak plasma concentric with, and having a major radius less than the majors radius of, said ring core.

Claim 33

An apparatus for producing and confining a spheromak plasma, comprising: a vacuum vessel having a major axis and an equatorial midplane; equilibrium field coil means for producing an equilibrium magnetic field directed primarily along the major axis; a ring core disposed within said vacuum vessel symmetrically with respect to said major axis and said equatorial midplane, and having a minor axis in said equatorial plane wound about said major axis, a major radius and a minor radius, said ring core including a toroidal flux coil surrounding said minor axis and a separate poloidal flux coil and being supported within said vacuum vessel by a plurality of ring supports, said ring supports housing conductors for supplying current to said poloidal and toroidal flux coils; means for energizing said equilibrium field coils at a time t 1 to create a first poloidal magnetic field within said vacuum vessel; means for energizing said poloidal flux coil at a time t 2 >t 1 to create a second poloidal magnetic field within said vacuum vessel, said first and second poloidal fields being super-imposed to form a composite poloidal field whose strength is greater on a radially exterior major radius side of said ring core, than on a radially interior major radius side of said ring core; means for energizing said toroidal flux coil at a time t 3 >t 1 for initiating a plasma discharge within said vacuum vessel, said ring core and said equilibrium field coils being operable to cause said plasma to become expanded and distended toward said major axis; and means, located on said radially interior side of said ring core, for pinching off a portion of said distended plasma, whereby a detached spheromak plasma is produced.

Claim 34

An apparatus for producing and confining a spheromak plasma, comprising: a vacuum vessel having a major axis and an equatorial midplane; equilibrium field coil means for producing an equilibrium magnetic field directed primarily along the major axis; a ring core disposed within said vacuum vessel symmetrically with respect to said major axis and said equatorial midplane, and having a minor axis in said equatorial plane wound about said major axis, a major radius and a minor radius, said ring core including a toroidal flux coil surrounding said minor axis and a separate poloidal flux coil and being supported within said vacuum vessel by a plurality of ring supports, said ring supports housing conductors for supplying current to said poloidal and toroidal flux coils; means for energizing said equilibrium field coils at a time t 1 to create a first poloidal magnetic field within said vacuum vessel; means for energizing said poloidal flux coil at a time t 2 >t 1 to create a second poloidal magnetic field within said vacuum vessel, said first and second poloidal fields being super-imposed to form a composite poloidal field whose strength is greater on a radially exterior major radius side of said ring core, than on a radially interior major radius side of said ring core; means for energizing said toroidal flux coil at a time t 3 >t 1 for initiating a plasma discharge within said vacuum vessel, said ring core and said equilibrium field coils being operable to cause said plasma to become expanded and distended toward said major axis; and means, located on said radially interior side of said ring core, for pinching off a portion of said distended plasma, whereby a detached spheromak plasma is produced.

Claim 35

An apparatus for producing and confining a spheromak plasma, comprising: a vacuum chamber having a major axis and an equatorial midplane, first coil means for producing a first poloidal magnetic field in said vacuum chamber at a time t 1 , a ring core having a minor axis surrounding said major axis disposed symmetrically within said vacuum chamber with respect to said equatorial plane and said major axis, said ring core including: second coil means for producing a second poloidal vacuum magnetic field in said vacuum chamber at a time t 2 >t 1 , said second poloidal vacuum magnetic field being a time-varying field; and third coil means operative for producing a time varying toroidal magnetic field inside said ring core at a time t 3 >t 1 , and for initiating in the presence of a gas a plasma discharge in said vacuum chamber; said first and second poloidal magnetic fields, when superimposed, forming a composite poloidal magnetic field having a strength which is weaker on a radially interior major radius side of said ring core than on a radially exterior major radius side of said ring core, such that said plasma expands into the region of weaker magnetic field; and means, located on said radially interior side of said ring core, for pinching off a portion of the expanded plasma and for causing reconnection of the magnetic field lines thereof, thereby forming a detached spheromak plasma.

Claim 36

An apparatus for producing and confining a spheromak plasma, comprising: a vacuum chamber having a major axis and an equatorial midplane, first coil means for producing a first poloidal magnetic field in said vacuum chamber at a time t 1 , a ring core having a minor axis surrounding said major axis disposed symmetrically within said vacuum chamber with respect to said equatorial plane and said major axis, said ring core including: second coil means for producing a second poloidal vacuum magnetic field in said vacuum chamber at a time t 2 >t 1 , said second poloidal vacuum magnetic field being a time-varying field; and third coil means operative for producing a time varying toroidal magnetic field inside said ring core at a time t 3 >t 1 , and for initiating in the presence of a gas a plasma discharge in said vacuum chamber; said first and second poloidal magnetic fields, when superimposed, forming a composite poloidal magnetic field having a strength which is weaker on a radially interior major radius side of said ring core than on a radially exterior major radius side of said ring core, such that said plasma expands into the region of weaker magnetic field; and means, located on said radially interior side of said ring core, for pinching off a portion of the expanded plasma and for causing reconnection of the magnetic field lines thereof, thereby forming a detached spheromak plasma.

Claim 37

A method for producing and confining a spheromak plasma, comprising: evacuating a vacuum vessel and filling said vessel with a neutral species; producing a first poloidal magnetic field by pulsing a current through a pair of toroidal equilibrium field coils; producing a second poloidal magnetic field by pulsing a current through a poloidal field generating coil of a ring core, such that said first and second poloidal magnetic fields are superimposed to form a composite poloidal field having first and second regions, the poloidal field in said second region being stronger than the poloidal field in said first region; producing a toroidal magnetic field inside said ring core by passing a current through a toroidal field generating coil of said ring core, thereby initiating a plasma discharge and causing toroidal flux to appear outside of said ring core; expanding the plasma in the direction of said first region; and pinching off a portion of said expanded plasma with a pinching coil located in said first region so as to cause poloidal magnetic field line reconnection within the pinched-off portion, thereby producing a detached spheromak plasma.

Claim 38

A method for producing and confining a spheromak plasma, comprising: evacuating a vacuum vessel and filling said vessel with a neutral species; producing a first poloidal magnetic field by pulsing a current through a pair of toroidal equilibrium field coils; producing a second poloidal magnetic field by pulsing a current through a poloidal field generating coil of a ring core, such that said first and second poloidal magnetic fields are superimposed to form a composite poloidal field having first and second regions, the poloidal field in said second region being stronger than the poloidal field in said first region; producing a toroidal magnetic field inside said ring core by passing a current through a toroidal field generating coil of said ring core, thereby initiating a plasma discharge and causing toroidal flux to appear outside of said ring core; expanding the plasma in the direction of said first region; and pinching off a portion of said expanded plasma with a pinching coil located in said first region so as to cause poloidal magnetic field line reconnection within the pinched-off portion, thereby producing a detached spheromak plasma.