A seismic signature of a second dynamo?

TL;DR

This paper identifies a distinct 2-year seismic signal in the Sun's oscillation frequencies, suggesting a possible second dynamo mechanism influencing solar magnetic activity alongside the well-known 11-year cycle.

Contribution

It provides evidence for a separate 2-year solar dynamo signature affecting oscillation frequencies, indicating a more complex magnetic activity cycle.

Findings

Detection of a quasi-biennial signal in solar oscillation frequencies

The 2-year signal is distinct yet influenced by the 11-year cycle

Implications for multiple dynamo processes in the Sun

Abstract

The Sun is a variable star whose magnetic activity varies most perceptibly on a timescale of approximately 11 years. However, significant variation is also observed on much shorter timescales. We observe a quasi-biennial (2 year) signal in the natural oscillation frequencies of the Sun. The oscillation frequencies are sensitive probes of the solar interior and so by studying them we can gain information about conditions beneath the solar surface. Our results point strongly to the 2 year signal being distinct and separate from, but nevertheless susceptible to the influence of, the main 11 year solar cycle.