Abstract: A microwave switch selectively directs a microwave signal along first and second signal paths. The switch includes a microwave transmission member, a microwave chamber formed by the transmission member for containing an ionizable gas, input and output ports formed by the transmission member to communicate with the microwave chamber and a triggered plasma generator which is configured to generate, in response to a voltage trigger signal, a trigger electron density N.sub.t in the gas. The microwave signal increases the trigger electron density N.sub.t to a reflective electron density N.sub.r. Consequently, the microwave signal is reflected along a first path from the input port when the trigger electron density N.sub.t is present and is directed along a second path to the output port when the trigger electron density N.sub.t is absent. A plurality of these microwave switches is arranged to form a tunable microwave short.

Abstract: A CROSSATRON plasma switch has a peak current capability in excess of 10kA and a switching speed of at least 1.times.10.sup.11 A/sec, making it compatible with the requirements of excimer and CO.sub.2 gas laser switches, and yet is small enough to be mechanically integrated with such lasers. It employs an axially corrugated cathode with a body diameter on the order of 10 cm and shallow corrugations whose depths are about 1.0-1.5 times the distance between corrugations, together with a reduced diameter anode (of about 2.5 cm diameter for an excimer laser and about 1.25 cm diameter for a CO.sub.2 laser), to obtain a plasma volume of about 50-100 cm.sup.3 for rapid switching. A magnet assembly around the cathode uses only two stacked magnets, but has an overall greater axial length and surface magnetic strength than in prior switches. The magnet design produces a high field strength near the cathode, but without a significant extension of the field into the anode region.

Abstract: A CROSSATRON switch is capable of operating with voltages in excess of 100 kV by the use of a deuterium gas fill to increase the Paschen breakdown voltage, axial molybdenum cathode corrugations to provide a higher current capability, and a Paschen shield that is formed from molybdenum. The terminal curvature of the Paschen shield and of the adjacent portion of the anode are selected to establish a voltage stress at the curved Paschen shield surface within the approximate range of 90-150 kV/cm in response to a 100 kV differential.

Abstract: A diverging magnetic field is established between the cathode and control electrode of a hollow cathode plasma switch to expand the plasma at a passageway through the control electrode, thus significantly increasing the switch's current handling capability. Preferred ranges of magnetic field strength, gas pressure, spacing between the hollow cathode and control electrode, and the mesh aperture size for the control grid are described.

Abstract: A hollow cathode capable of self-heating by back ion bombardment to a thermionic emission temperature axially discharges therefrom an ionized plasma of an ambient gas such as xenon. Electrons are axially or radially extractable from the plasma by an anode. A voltage is applied to a keeper electrode disposed between the cathode and anode to sustain plasma discharge of the gas between the cathode and keeper electrode. A control electrode is disposed between the keeper electrode and the anode. Application of a positive voltage (relative to the cathode) to the control electrode causes the plasma discharge to extend from the cathode to the anode, thus closing the switch. Application of a negative control electrode voltage, or simply returning the control electrode to cathode potential, causes the plasma discharge to retract back to the area of the keeper electrode, thereby opening the switch.

Abstract: An axial electrostatic ion thruster for use on a dual-spin stabilized spacecraft is disclosed. The thruster is mounted on the spun portion of the spacecraft and continuously fired for an integral number of spin periods to provide north-south velocity and attitude control. To achieve zero attitude precession with a statically imbalanced despun platform, or an intentional attitude precession generally, the ion thrust is spin-synchronously varied between two non-zero levels to achieve a prescribed Fourier component amplitude and phase at the spin frequency. Modulation of the thrust is achieved with constant ion beam current by complementary modulation of the beam voltage, V.sub.B, and accel voltage, V.sub.A by varying the ion extraction system grid voltages. This varies the thrust while maintaining a constant total accelerating voltage V.sub.TOT =V.sub.B +.vertline.V.sub.A .vertline..