Latest news on zebra pattern

TL;DR

This survey reviews recent observations and theories of zebra patterns in solar radio bursts, highlighting the dominant double plasma resonance mechanism and discussing challenges and alternative explanations.

Contribution

It provides a comprehensive overview of recent advances, observational data, and theoretical debates regarding the radiation mechanisms of zebra patterns in solar radio emissions.

Findings

Double plasma resonance remains the most accepted mechanism.

Challenges exist in explaining complex zebra structures with existing models.

Debates continue over the role of plasma wave interactions with whistlers.

Abstract

The publications of the last three years concerning the study of the most intriguing fine structure in type IV solar radio bursts, zebra pattern (ZP), are surveyed. The main attention is paid to new observations, irrespective of whether a paper includes detailed interpretation of an event or simply reports the beginning of operation of a new tool. The radiation mechanism of a ZP on a double plasma resonance (DPR) remains the most widespread and standard, though ten alternative mechanisms have been offered. However, in a number of works difficulties with the explanation of a complex zebra are noted, especially in combination with fiber bursts and spikes. Therefore, several papers in which description of the radiation mechanism of a ZP on the DPR is improved are considered in more detail. Without positional observations we have a great opportunity to follow the dynamics of flare processes using SDO / AIA images in several EUV lines. In the discussion, the debatable questions regarding the comparison of mechanisms associated with DPR in terms of the model of interaction of plasma waves with whistlers are illuminated.