Defense Intelligence Reference Document Inertial Electrostatic Confinement Fusion

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intense quasi-neutral ion jet. The configuration, low gas leakage, and good heat
removal make it possible to scale the design to either low powers or high powers,
covering a range of interest for present small satellites on to future medium and large
satellites. In addition to maneuverable thrusting, the jet channel extraction technique
enables directing and focusing the plasma stream down on an asteroid or other object
for interrogation of it. Analysis of the plasma emission spectra would provide an
identification of the materials and surface features of the object. With further
development the IEC system potentially offers an attractive fusion power source.
Another advantage of the IEC jet thruster is that it provides a step towards a future p-
11 B IEC power source and/or thruster for satellite operations. This possibility is also
briefly discussed here.
Relation to Other Prior Thrusters
NASA and other laboratories have worked toward developing advanced Hall Thrusters
for future satellite applications. Such thrusters, however, do not scale well to lower
powers for small satellites, nor are exhaust plasma modifications possible to provide
fast maneuverability. The IEC-jet thruster appears uniquely able to address both issues.
Conventional plasma thrusters such as the Hall thruster have undergone much more
experimental study than the IEC-jet thruster. However, the simplicity of the IEC-Jet
thruster design and its thermal scalability makes it feasible to quickly develop and test,
making the lack of data base less of a liability.
In the jet thruster concept the plasma target at the center of the chamber, created by
the intersection of the multiple ion beams, serves to deflect ions into the escaping jet
plasma. The resulting virtual anode, in combination with curved potential lines created
by the cathode grid diverts ions, forming a strong plasma jet. This is channeled out
through an enlarged hole and guide structure in the grid (Figure 3.2). This design
promises a good efficiency and thrust while providing a low weight, and due to the very
open accelerator grid structure, a very long lifetime. Thus it provides a good thruster
for basic satellite operations and with the added jet control/focusing also provides
maneuverability.
In addition the IEC jet offers two added features that increase its potential effectiveness
for probing various space objects. The fact that the IEC jet can be controlled to form
over multiple areas around the sphere would allow the platform to maneuver itself close
to a target and then simply open a second jet offset 180 degrees from the propulsive
one. The second jet would serve the integration purpose of the platform without having
to expend time or additional resources such as fuel to reorient itself to direct the plume
at the target. Other current systems, such as Hall thrusters, would first have to position
itself close to the target, and then reorient such that the exhaust plume is properly
oriented. Thus, the IEC jet thruster would not be subject to expending the resources of
time and fuel that other platforms require. Another option for the IEC jet thruster is to
operate as a pulsed device. This becomes especially important when considering how
long it may take to disable a defensive target (the platform's impulse time to disable).
The use of an intense pulsed jet could disable the target before it has time to maneuver
or apply defensive layers. As discussed later, the basic IEC has been operated
experimentally in a pulsed mode using a capacitive power unit. However, to date,
formation of the jet has only been studied under steady-state operation.
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