Decameter Type III-Like Bursts

TL;DR

This study reports the first observations of high drift rate Type III-like radio bursts in the decameter range, analyzing over 1100 events and comparing their properties to normal Type III bursts.

Contribution

First detection and detailed analysis of decameter Type III-like bursts, including their polarization and drift rates, expanding understanding of solar radio emissions.

Findings

Drift rates of 5-10 MHz/s, several times higher than normal Type III bursts.

Durations of 1-2 seconds, shorter than usual Type III bursts.

Similar polarization characteristics to Type III bursts.

Abstract

Starting from 1960s Type III-like bursts (Type III bursts with high drift rates) in a wide frequency range from 300 to 950MHz have been observed. These new bursts observed at certain frequency being compared to the usual Type III bursts at the same frequency show similar behaviour but feature frequency drift 2-6 times higher than the normal bursts. In this paper we report the first observations of Type III-like bursts in decameter range, carried out during summer campaigns 2002 - 2004 at UTR-2 radio telescope. The circular polarization of the bursts was measured by the radio telescope URAN-2 in 2004. The observed bursts are analyzed and compared with usual Type III bursts in the decameter range. From the analysis of over 1100 Type III-like bursts, their main parameters have been found. Characteristic feature of the observed bursts is similar to Type III-like bursts at other frequencies, i.e. measured drift rates (5-10 MHz/s) of this bursts are few times larger than that for usual Type III bursts, and their durations (1-2 s) are few times smaller than that for usual Type III bursts in this frequency band.