Magnetic field geometry for crossed-field devices

Claim 2

In a crossed-field device having a generally cylindrical cathode and an anode circumferentially disposed thereabout defining an electronic interaction area therebetween, the improvements comprising: means for generating the magnetomotive force necessary to provide the magnetic field of said device; means associated with said generating means for forming a partial magnetic circuit disposed exterior of and adjacent to one end of said cathode; means forming an evacuable envelope enclosing said interaction area and means completing said partial magnetic circuit disposed adjacent to the other end of said cathode in the region of said interaction area, said generating means comprising a main magnet encompassed by the cathode of said device and disposed outside the vacuum envelope thereof, whereby a compact crossed-field device is provided in which the magnetomotive force is at the potential of the cathode and is removable without affecting the vacuum envelope thereof.

Claim 3

The device as defined in claim 1 wherein said enveloe forming means defines a central opening of regular cross-section without said envelope and said magnet is a permanent magnet disposed in said central opening.

Claim 4

The device as defined in claim 2 and further including means forming passages for coolant flow adjacent the interior surface of said cathode, said permanent magnet and said means completing said partial magnetic circuit disposed interior of said means forming passages for coolant flow.

Claim 5

The device as defined in claim 3 wherein said permanent magnet is made of samarium cobalt so that a compact crossed-field device is formed whose permanent magnet may be removed and replaced without affecting the evacuated volume of the device.

Claim 6

In a crossed-field device having a generally cylindrical cathode and an anode circumferentially disposed thereabout defining an electronic interaction area therebetween, the improvements comprising: means for generating the magnetomotive force necessary to provide the magnetic field for said device; means associated with said generating means for forming a partial magnetic circuit disposed exterior of and adjacent to one end of said cathode; said magnetic circuit formed of upper and lower pole pieces, said means associated with said generating means forming passages for coolant flow so that a compact crossed-field device is formed whose permanent magnet may be removed and replaced without affecting the evacuated volume of the device, said upper pole piece unitary and disposed entirely within the evacuable envelope, said lower pole piece fragmented and including a circumferential segment one end of which forms said interaction area with a corresponding end of said upper pole piece and the other end of which terminates within said cathode, a circumferential end cap spaced from and in register with said other end of said segment, and a transverse segment adjacent to and substantially contacting said end cap, means forming an evacuable envelope enclosing said partial magnetic circuit; said envelope forming means defining a central opening of regular cross-section within said envelope; means completing said partial magnetic circuit disposed adjacent to the other end of said cathode in the region of said interaction area, said generating means including a main samarium cobalt permanent magnet encompassed by the cathode of said device and disposed in saiD central opening so that the magnetomotive force is at the potential of the cathode; said permanent magnet and said means completing said partial magnetic circuit disposed interior of said circumferential segment disposed in said evacuable envelope, said circumferential end cap disposed in said passage forming means, said transverse segment removably received in said central opening, whereby a compact crossed-field device is provided which has a removable permanent magnet disposed outside the evacuated envelope and in which the magnetomotive force is at the potential of the cathode.

Claim 7

In a crossed-field device having a generally cylindrical cathode and an anode circumferentially disposed thereabout defining an electronic interaction area therebetween, the improvements comprising: means for generating the magnetomotive force necessary to provide the magnetic field for said device; means associated with said generating means for forming a partial magnetic circuit disposed exterior of and adjacent to one end of said cathode; said magnetic circuit formed of upper and lower pole pieces, said means associated with said generating means forming passages for coolant flow so that a compact crossed-field device is formed whose permanent magnet may be removed and replaced without affecting the evacuated volume of the device, said upper pole piece unitary and disposed entirely within the evacuable envelope, said lower pole piece fragmented and including a circumferential segment one end of which forms said interaction area with a corresponding end of said upper pole piece and the other end of which terminates within said cathode, a circumferential end cap spaced from and in register with said other end of said segment, and a transverse segment adjacent to and substantially contacting said end cap, means forming an evacuable envelope enclosing said partial magnetic circuit; said envelope forming means defining a central opening of regular cross-section within said envelope; means completing said partial magnetic circuit disposed adjacent to the other end of said cathode in the region of said interaction area, said generating means including a main samarium cobalt permanent magnet encompassed by the cathode of said device and disposed in saiD central opening so that the magnetomotive force is at the potential of the cathode; said permanent magnet and said means completing said partial magnetic circuit disposed interior of said circumferential segment disposed in said evacuable envelope, said circumferential end cap disposed in said passage forming means, said transverse segment removably received in said central opening, whereby a compact crossed-field device is provided which has a removable permanent magnet disposed outside the evacuated envelope and in which the magnetomotive force is at the potential of the cathode.

Claim 10

The method of claim 6 and further including defining the area through which the magnetic field forming material and the external portion of the flux path are inserted by nonmagnetizable material; and forming liquid coolant passages between the interior surface of the cathode and the area defining material.