Improved and simplified design of the relativistic helitron resonator

Abstract

One of the main trends in microwave electronics is the ultra-large power production. The electron stream energy is converted inside vacuum systems, where the key moment is increasing output power of microwave devices, which is possible only when using more and more powerful electron streams. Increasing electron stream power is possible due to either enhancing the carried currents or as a result of increasing the electron energy. Given the law that connects currents and voltages in electronic systems operating when the current is limited by a spatial charge, the production of ultra-high-power electron flows is associated with the usage of relativistic velocity electrons, i. e. approaching the light speed. Likewise, at present, relativistic electrovacuum devices (traveling-wave lamps and backward-wave lamps) use magnetic focusing for linear relativistic streams, which prevents the implementation of simple superconducting electrodynamic systems, because highfrequency metal superconductivity disappears in constant magnetic fields. Meanwhile, simplified ultra-highpower superconducting device structures can significantly increase the device energy due to the strong ohmic loss reduction, which just limits the device energy, destroying the working electrodynamic system surface by increasing power or pulse duration of the generator. The article outlines the modernized design of a new-type microwave generator – the relativistic helitron. The paper considers a simpler coaxial resonator design, obtained by using the supercritical narrowing of the inner conductor radius by the Hn1l mode of the electromagnetic field, rather than a coaxial resonator with notch filters.

Keywords

• helitron
• critical wavelength
• coaxial waveguide