Multipactor discharge on a dielectric surface in the field of circularly polarized plane waves

Abstract

The secondary-emission discharge (multipactor) on a dielectric surface irradiated by a plane TEM wave of circular polarization is analyzed theoretically. It is shown that interaction of electrons with the electromagnetic wave field can provide their return to the emission surface, which makes a multipactor possible even without any external static fields. Multipactor conditions for different reflection coefficients of the incident wave are found. The obtained results are used to estimate the throughput of the output window of a high-power vacuum microwave device. Specifically, it is established that decreasing the high-frequency field amplitude on the window surface when the mode of a partially standing wave is realized in the vicinity of the window does not always help raise its electric strength.

Effects of rf magnetic field and wave reflection on multipactor discharge on a dielectric

“…In this paper, we present a statistical theory of multipactor discharge on a dielectric exposed to circularly polarized rf field extending available theoretical treatment proposed for the constant emission velocity model. 8,9 The most striking difference between the statement considered and earlier studies of discharge driven by linearly polarized plane wave consists in the absence of rf phase dependence on transit time and impact energy, so that the discharge will be polyphase at all the stages. Our main interest is to obtain the multipacting discharge cutoff conditions and the saturation level including the effects of rf magnetic field and partial reflection of the incident electromagnetic wave.…”

“…In this context, it should be noted that analysis of the effect of the action of spatially inhomogeneous electromagnetic field on the multipactor development was undertaken by Buyanova et al 8,9 who have employed the dynamic approach. In this paper, we present a statistical theory of multipactor discharge on a dielectric exposed to circularly polarized rf field extending available theoretical treatment proposed for the constant emission velocity model.…”

Simulations of multipactor in circular waveguides

“…This type of discharge is an undesirable phenomenon in many practical microwave applications and the intense study of this phenomenon during the last decades has mainly been stimulated by the necessity to be able to accurately predict the multipactor threshold in different microwave subsystems. [1][2][3][4][5] These studies have resulted in development of various numerical tools capable of simulating multipactor in different geometries including parallel plates, 6,7 coaxial cables, [8][9][10] dielectric windows, [11][12][13] rectangular and wedge-shaped waveguides, [14][15][16] microstrip lines, 17 waveguide irises, [18][19][20] and rf filters and transformers. [21][22][23] A notable exception is multipactor breakdown in circular waveguides, which has been given scant interest, in spite of its technical importance.…”

Suppressing and initiation of multipactor discharge on a dielectric by an external dc bias

“…It was shown in [16,17] theoretically and experimentally that multipactor can take place on a dielectric surface in strong electromagnetic fields even in the absence of external static fields, since an inhomogeneous microwave field can by itself ensure the return of the emitted electrons to the surface. Indeed, in an inhomogeneous microwave field, an electron is affected by the averaged ponderomotive force F , which is proportional to the gradient of the rf electric field [18].…”

“…$ 150-200 ns. The effect of the inhomogeneous microwave field on the multipactor was studied in detail in [16,17].…”