Abstract: Orbital debris removal (ODR) systems under the present approach may use a ground- or surface-based FEL and mirror system with sufficient power and both spatial and temporal resolution to both locate Category II OD (1 cm to 10 cm diameter) in low Earth orbit (LEO, 160 to 2000 km altitude) and remove these objects from orbit. Locating the Category II OD is performed by having the light beam from an FEL and its beam director scan a volume of space of interest and then observing the light reflected from the OD. Removing the OD may include heating the OD to a sufficiently high temperature to evaporate the OD, changing the orbit of the OD such as to lower the perigee, or both. Megawatt-class MOPA FELs for, inter alia, removing OD, are described.

Abstract: Orbital debris removal (ODR) systems under the present approach may use a ground- or surface-based FEL and mirror system with sufficient power and both spatial and temporal resolution to both locate Category II OD (1 cm to 10 cm diameter) in low Earth orbit (LEO, 160 to 2000 km altitude) and remove these objects from orbit. Locating the Category II OD is performed by having the light beam from an FEL and its beam director scan a volume of space of interest and then observing the light reflected from the OD. Removing the OD may include heating the OD to a sufficiently high temperature to evaporate the OD, changing the orbit of the OD such as to lower the perigee, or both. Megawatt-class MOPA FELs for, inter alia, removing OD, are described.

Abstract: Orbital debt is removal (ODR) systems under the present approach may use a ground- or surface-based FEL and mirror system with sufficient power and both spatial and temporal resolution to both locate Category II OD (1 cm to 10 cm diameter) in low Earth orbit (LEO, 160 to 2000 km altitude) and remove these objects from orbit. Locating the Category II OD is performed by having, the light beam from an FEL and its beam director scan a volume of space of interest and then observing the light reflected from the OD. Removing the OD may include heating the OD to a sufficiently high temperature to evaporate the OD, changing the orbit of the OD such as to lower the perigee, or both. Megawatt-class MOPA FELs for, inter alia, removing OD, are described.

Abstract: Orbital debris removal (ODR) systems under the present approach may use a ground- or surface-based FEL and mirror system with sufficient power and both spatial and temporal resolution to both locate Category II OD (1 cm to 10 cm diameter) in low Earth orbit (LEO, 160 to 2000 km altitude) and remove these objects from orbit. Locating the Category II OD is performed by having the light beam from an FEL and its beam director scan a volume of space of interest and then observing the light reflected from the OD. Removing the OD may include heating the OD to a sufficiently high temperature to evaporate the OD, changing the orbit of the OD such as to lower the perigee, or both. Megawatt-class MOPA FELs for, inter alia, removing OD, are described.

Abstract: A radio frequency (RF) modulating signal splitter used by a multi-beam electron beam RF amplification system includes an RF input port and a plurality of RF output ports. A body frame distributes the RF modulating signal from the input port to the of output ports. The body frame and each one of the RF output ports have dimensions so that each one of the plurality of RF output ports is impedance matched with each other. In a method of modulating a RF input signal onto a plurality of electron beams, the RF input signal is split into a plurality of different paths directed to a plurality of output ports that are impedance matched to each other. RF energy is directed from each output port to a different input cavity of electronic beam RF amplification devices of a multi-beam electronic beam RF amplification system.

Abstract: A radio frequency (RF) modulating signal splitter used by a multi-beam electron beam RF amplification system includes an RF input port and a plurality of RF output ports. A body frame distributes the RF modulating signal from the input port to the of output ports. The body frame and each one of the RF output ports have dimensions so that each one of the plurality of RF output ports is impedance matched with each other. In a method of modulating a RF input signal onto a plurality of electron beams, the RF input signal is split into a plurality of different paths directed to a plurality of output ports that are impedance matched to each other. RF energy is directed from each output port to a different input cavity of electronic beam RF amplification devices of a multi-beam electronic beam RF amplification system.

Abstract: An electromagnetic wiggler having a cylindrical member, and a central member disposed axially within the cylindrical member, both of which are formed from alternating cylindrical sections of ferromagnetic and non-ferromagnetic material, each sequential pair of these sections being the length of the wiggler's period .lambda..sub.w. The sequence of sections between the inner and outer members is shifted .lambda..sub.w /2, so that ferromagnetic sections of the outer member are disposed radially opposite non-ferromagnetic sections of the inner member, and vice versa. The resultant radial magnetic flux density in the cylindrical gap between the members is larger and sharper than the flux density for the same wiggler without the central member, permitting higher radiated power output, at higher radiation frequencies, for the same energy of input electron beam.

Abstract: A free electron laser for emitting coherent radiation. The laser includes a wiggler magnet for producing a spatially periodic magnetic field in a drift region into which relativistic electrons are injected in a predetermined direction. An axial magnet is provided which generates an axial magnetic field parallel to the above predetermined direction. The axial field is tapered in field strength within a uniform wiggler region, wherein the wiggler field is of uniform and constant magnitude, such that the tapered field acts to oppose the change in axial electron velocity resulting from the free electron laser interaction as electrons travel through the drift region. The tapered axial field acts to enhance power output and efficiency.