Coherent x-ray radiation induced by high-current breakdown on a ferrite surface

TL;DR

This study reports the first observation of coherent, directional x-ray radiation generated during high-current breakdown on a ferrite surface, linked to surface magnetization effects.

Contribution

It introduces a novel observation of coherent x-ray emission during high-current discharge on ferrite, proposing a new mechanism involving surface magnetization and interference.

Findings

X-ray radiation is highly directional and coherent.

Radiation energy flux density depends quadratically on ferrite active area.

Radiation occurs within the initial stage of high-current breakdown.

Abstract

We for the first time observe that at the initial stage of a high-current discharge, a low-divergence short (< 2 ns) electromagnetic pulse is formed over a ferrite surface. The 50% part of this pulse lies in the region of fairly hard x-ray radiation (photon energy >1 keV) with the energy $\approx$0.6 mJ and the average power 0.3 MW. The radiation propagates parallel to the surface in the anode direction with the angle divergence < 2$^{o}$. The high directionality of the radiation in absence of the aperture-limiting devices for the radiation beam and the quadratic dependence of the spatial radiation energy flux density on the active part of the ferrite prism points to the coherent nature of the observed radiation. A possible generation mechanism of the radiation is proposed. It is based on the short-lived magnetization of the unit areas on the ferrite surface by a high-power electromagnetic pulse and subsequent coherent interference of the unit waves irradiated by these areas.