Dimensional Bounds on Vircator Emission

TL;DR

This paper derives fundamental dimensional bounds on the maximum power and energy of vircator microwave emissions based on physical constants and device dimensions, highlighting potential for higher outputs with relativistic electrons.

Contribution

It introduces a dimensional analysis framework to establish upper bounds on vircator emission power and energy, connecting device parameters to fundamental physical limits.

Findings

Peak power limited to ~30 GW for given dimensions and voltages.

Maximum broad-band energy around 3 J for specified device parameters.

Relativistic electrons could enable higher power and energy outputs.

Abstract

Vircators (Virtual Cathode Oscillators) are sources of short-pulsed, high power, microwave (GHz) radiation. An essentially dimensional argument relates their radiated power, pulse energy and oscillation frequency to their driving voltage and fundamental physical constants. For a diode of width and gap 10 cm and for voltages of a few hundred keV the peak radiated power cannot exceed ${\cal O} (\text{30 GW})$ and the broad-band single cycle radiated energy cannot exceed ${\cal O}(\text{3 J})$. If electrons can be accelerated to relativistic energies higher powers and radiated energies may be possible.