A framework for describing correlated excitation of solar p modes

TL;DR

This paper proposes a theoretical framework for understanding correlated excitation of solar p modes, suggesting that mode overtones are temporally correlated, which affects the power spectral density and observed peak asymmetries.

Contribution

It introduces a mathematical model for correlated mode excitation in solar p modes, providing insights into subtle spectral modifications and peak asymmetries.

Findings

Correlated excitation affects the power spectral density.

Signatures of correlation are subtle, not in amplitude correlations.

Contributes to understanding observed peak asymmetries.

Abstract

In a previous paper we suggested that, for a given p mode, the excitation function is the same as the component of the solar background noise that has an identical surface spherical harmonic projection (over the corresponding range of temporal frequency). An important consequence of this surmise is that the excitation of overtones of a given angular degree and azimuthal order will be correlated in time. In this note, we introduce the basic principles and a mathematical description of correlated mode excitation. We use simple, illustrative examples, involving two modes. Our treatment suggests that in the real observations, any signatures of the correlation would not appear as a correlation of the output amplitudes of overtones, but rather as subtle modifications to the power spectral density at frequencies between the central frequencies of the overtones. These modifications give a contribution to the observed peak asymmetries.