What do global p-modes tell us about banana cells?

TL;DR

This paper investigates how giant convection cells, or banana cells, influence p-mode splitting coefficients, suggesting observational detection methods and analyzing data to identify these large-scale solar features.

Contribution

The study applies quasi-degenerate perturbation theory to estimate frequency shifts caused by banana cells and proposes a detection approach using observational data.

Findings

Banana cells with azimuthal wave number 16 are consistent with GONG data.

Even splitting coefficients can reveal the presence of giant convection cells.

Detection of banana cells remains plausible with current helioseismic observations.

Abstract

We have calculated the effects of giant convection cells also know as sectoral rolls or banana cells, on p-mode splitting coefficients. We use the technique of quasi-degenerate perturbation theory formulated by Lavely & Ritzwoller in order to estimate the frequency shifts. A possible way of detecting giant cells is to look for even splitting coefficients of 'nearly degenerate' modes in the observational data since these modes have the largest shifts. We find that banana cells having an azimuthal wave number of 16 and maximum vertical velocity of 180 m/s cannot be ruled out from GONG data for even splitting coefficients.