Abstract: In one embodiment, a fastener includes a flexible head and a shank coupled to the flexible head. The flexible head includes a center head portion and a plurality of wing portions coupled to the center head portion. Each of the plurality of wing portions includes a contact area configured to contact a first surface of a part to be fastened. The shank includes a clip groove configured to hold a retainer clip against a second surface of the part to be fastened. The second first surface of the part to be fastened is opposite the first surface of the part to be fastened.

Abstract: In one embodiment, systems and methods include using a Langmuir probe to measure a plasma. The Langmuir probe comprises a housing, wherein the housing comprises an outer diameter and an inner diameter, wherein the inner diameter defines an internal cavity. The Langmuir probe further comprises a plurality of bodies, wherein the plurality of bodies is disposed at least partially within the inner cavity, wherein each of the plurality of bodies comprise a set of internal cavities. The Langmuir probe further comprises a plurality of double Langmuir probes disposed each set of the internal cavities.

Abstract: A monolithic heating element is provided. In one embodiment, the heating element includes a monolithic structure that is not a filament and a plurality of electrodes attached to the monolithic structure. Application of an electric current between the plurality of electrodes generates heat in the monolithic structure which can be tailored to any desired heating profile and is robust to single point failures due to thermal runaway.

Abstract: In one embodiment, a system includes a cathode and a thermionic emitter installed at least partially within the cathode tube of the cathode. The thermionic emitter is in a shape of a hollow cylinder. The hollow cylinder includes an outer surface and an unsmooth inner surface. The outer surface is configured to contact an inner surface of the cathode tube. The unsmooth inner surface includes a plurality of structures that provide an increase in surface area over a smooth surface.

Abstract: In one embodiment, a system includes a cathode and a thermionic emitter installed at least partially within the cathode tube of the cathode. The thermionic emitter is in a shape of a hollow cylinder. The hollow cylinder includes an outer surface and an unsmooth inner surface. The outer surface is configured to contact an inner surface of the cathode tube. The unsmooth inner surface includes a plurality of structures that provide an increase in surface area over a smooth surface.

Abstract: In one embodiment, a system includes a thermionic emitter and a heater at least partially surrounding the thermionic emitter. The heater is configured to heat the thermionic emitter. The heater includes a first end, a second end opposite the first end, and a plurality of hollow insulating tubes that each run from the first end to the second end. The heater also includes a heater wire that runs through each of the hollow insulating tubes. The heater wire is configured to be resistively heated by an electrical current passed through the heater wire.