# Detection of Rossby waves in the Sun using normal-mode coupling

## TL;DR

This paper demonstrates the detection of Rossby waves in the Sun using normal-mode coupling analysis of two years of helioseismic data, providing an independent validation method and enhancing understanding of solar dynamics.

## Contribution

The study introduces the use of normal-mode coupling to detect Rossby waves in the Sun, offering an alternative approach to existing helioseismic techniques.

## Key findings

- Rossby waves detected in two years of HMI data
- Normal-mode coupling confirms signatures of Rossby waves
- Supports the validity of mode coupling as a helioseismic method

## Abstract

Rossby waves play a fundamental role in angular momentum processes in rotating fluids. In addition to the potential to shed light on physical mechanisms operating in the solar convection zone, the recent detection of Rossby waves in the Sun (L\"optien et al. 2018; Liang et al. 2018) also serves as a means of comparison between different helioseismic methods. Time-distance helioseismology, ring-diagram analysis and other techniques have all proven successful in recovering the Rossby-wave dispersion relation from analyses of Helioseismic and Magnetic Imager data (HMI; Schou et al. 2012). In this article, we demonstrate that analyses of two years of HMI global-mode-oscillation data using the technique of normal-mode coupling also show signatures of Rossby waves. In addition to providing an independent means of inferring Rossby waves, this detection lends credence to the methodology of mode coupling and encourages a more complete exploration of its possibilities.