CALLISTO facilities in Peru: spectrometer commissioning and observations of type III solar radio bursts

Abstract

The Astrophysics Directorate of CONIDA has installed two radio spectrometer stations belonging to the e-CALLISTO network in Lima, Peru. Given their strategic location near the Equator, it is possible to observe the Sun evenly throughout the whole year. The receiver located at Pucusana, nearby the capital city of Lima, took data from October 2014 until August 2016 in the metric and decimetric bands looking for radio bursts. During this period, this e-CALLISTO detector was unique in its time-zone coverage. To asses the suitability of the sites and the performance of the antennas, we analyzed the radio ambient background and measured their radiation pattern and beamwidth. To demonstrate the capabilities of the facilities for studying solar dynamics in these radio frequencies, we have selected and analyzed type III Solar Radio Bursts. The study of this kind of burst helps to understand the electron beams traversing the solar corona and the solar atmospheric density. We have characterized the most common radio bursts with the following mean values: a negative drift rate of –25.8 ± 3.7 MHz s−1, a duration of 2.6 ± 0.3 s and 35 MHz bandwidth in the frequency range of 114 to 174 MHz. In addition, for some events, it was possible to calculate a global frequency drift which on average was 0.4 ± 0.1 MHz s−1.

Decametric Solar Radio Spectrometer Based on 4-element Beamforming Array and Initial Observational Results

“…In the solar radio dynamic spectrum, type III bursts are the fast frequency drifting signatures. They are interpreted as the radio signatures of energetic electron beams propagating along the magnetic field lines in the corona or interplanetary space with a speed of 0.2-0.6c (Reid & Ratcliffe 2014;Rengifo et al 2021). On 2022 November 11, between 04:37:29 and 04:39:32 UT, an event was observed by our decametric spectrometer, with spectral resolution of 12 kHz and temporal resolution of 5.3 ms, as shown in the right panel of Figure 11, which displays the fine structures of the type III bursts.…”