Spatially and Spectrally Resolved Observations of a Zebra Pattern in Solar Decimetric Radio Burst

TL;DR

This study reports the first high-resolution interferometric observations of a zebra-pattern solar radio burst, providing insights into its source location, size, and magnetic environment, supporting the double-plasma resonance model.

Contribution

It presents the first simultaneous high spectral and temporal resolution interferometric observations of a zebra pattern in solar radio bursts, linking the emission to magnetic field structures.

Findings

Zebra source location mapped on the solar disk.

Source size and position vary with frequency and time.

Results support the double-plasma resonance model for zebra bursts.

Abstract

We present the first interferometric observation of a zebra-pattern radio burst with simultaneous high spectral (~ 1 MHz) and high time (20 ms) resolution. The Frequency-Agile Solar Radiotelescope (FASR) Subsystem Testbed (FST) and the Owens Valley Solar Array (OVSA) were used in parallel to observe the X1.5 flare on 14 December 2006. By using OVSA to calibrate the FST the source position of the zebra pattern can be located on the solar disk. With the help of multi-wavelength observations and a nonlinear force-free field (NLFFF) extrapolation, the zebra source is explored in relation to the magnetic field configuration. New constraints are placed on the source size and position as a function of frequency and time. We conclude that the zebra burst is consistent with a double-plasma resonance (DPR) model in which the radio emission occurs in resonance layers where the upper hybrid frequency is harmonically related to the electron cyclotron frequency in a coronal magnetic loop.