Effects of CsI Coating of Carbon Fiber Cathodes on the Microwave Emission From a Triode Virtual Cathode Oscillator

Characterization of Cesium Iodide-Coated Carbon-Fiber Aluminum Cathode for an <inline-formula> <tex-math notation="LaTeX">$S$ </tex-math></inline-formula>-Band High-Efficiency Vircator

“…3(b), the minimum plasma expansion velocity is around 3 cm/μs, which is about half that without CsI-coating [16]. The reduction factor of 50% is similar to that found in [20]. The plasma expansion velocity could be further reduced by baking and conditioning to remove the adsorbed water and air molecules on the cathode surface.…”

“…Characterization indicates that the plasma expansion velocity of the CFA cathode is in excess of about 6 cm/μs [16], which is high for applying to a vircator. It has been observed in the experiment that coating cesium iodide (CsI) on cathode surface can effectively suppress plasma expansion [17]- [20]; however, the function of CsI-coating on a CFA cathode has not been studied yet.…”

Modification of polymer velvet cathode via metallic Mo coating for enhancement of high-current electron emission performances

“…Therefore, these results suggest that Mo coating could effectively decrease cathode plasma expansion velocity of polymer velvet cathode because of the large mass of Mo, similar with the CsI-coated carbon fiber cathodes. 19,20,25,27 A simple simulation was performed by CHIPIC 3.0 with the FDTD algorithm, 28 assuming that cathode plasmas would expand toward the axial and radial direction with the same velocity and the expanded plasmas could be viewed as "new" cathode. When the fitted plasma expansion velocities of both two velvet cathodes were viewed as boundary conditions, the simulated cathode current with the diode voltage of 1.5 MV is 1.88 and 1.52 kA for uncoated and Mo-coated velvet cathodes, respectively, which is very close to the experimental values.…”

“…16,17 Surface coating with cesium iodide (CsI) on polymer velvet cathode is an alternative and effective strategy to reduce outgassing levels and decrease plasma expansion velocity, due to the low ionization potential and high mass of cesium. 9,18,19 However, the hygroscopicity and oxidizability of CsI in the atmosphere, 20,21 especially in the humid environment, restricted its wide application. Therefore, it is necessary to develop new surface modification technique for polymer velvet cathode to improve the high-current pulsed emission performances.…”

Surface modification and submicron structure of carbon fibers through high current pulse

“…Considerable experimental investigations were carried out on the emission characteristics of carbon fibers as field emitters under the external large electric field [13][14][15][16][17]. However, discusses on the property of carbon fibers, during the electrical explosion process, are scanty in the literature.…”