# Radio emission of air showers with extremely high energy measured by the Yakutsk radio array

## TL;DR

This paper reports on the Yakutsk Array's measurements of radio emissions from high-energy air showers, establishing empirical relations and detecting the highest energy cosmic ray events at the array.

## Contribution

It provides the first measurements of radio emission from air showers with energies exceeding 10^{19} eV at Yakutsk, including the highest energy event recorded there.

## Key findings

- Lateral distribution function of radio emission established.
- Empirical relation between radio amplitude and air shower energy derived.
- First detection of radio emission from air showers above 10^{19} eV at Yakutsk.

## Abstract

The Yakutsk Array is designed to study cosmic rays at energy 10$^{15}$-10$^{20}$ eV. It consists several independent arrays that register charged particles, muons with energy E$\geq$1 GeV, Cherenkov light and radio emission. The paper presents a technical description of the Yakutsk Radio Array and some preliminary results obtained from measurements of radio emission at 30-35 MHz frequency induced by air shower particles with energy $\varepsilon$ $\geq$ 1$\cdot$10$^{17}$ eV. The data obtained at the Yakutsk array in 1986-1989 (first set of measurements) and 2009-2014 (new set of measurements). Based on the obtained results we determined: Lateral distribution function (LDF) of air showers radio emission with energy $\geq$ 10$^{17}$ eV. Radio emission amplitude empirical connection with air shower energy. Determination of depth of maximum by the ratio of amplitude at different distances from the shower axis. For the first time, at the Yakutsk array, radio emission from the air shower with energy $>$ 10$^{19}$ eV was registered including the shower with the highest energy ever registered at the Yakutsk array with energy $\sim$2 $\cdot$ 10$^{20}$ eV.