In situ Evidence of 5-minute Oscillations from Parker Solar Probe

TL;DR

This paper reports the first in situ detection of 5-minute solar oscillations in the upper corona using Parker Solar Probe data, confirming that these oscillations influence the solar wind.

Contribution

It provides the first direct in situ evidence of 5-minute solar oscillations reaching the solar corona, previously only hypothesized.

Findings

Detection of statistically significant 3.1-3.2 mHz peaks in magnetic field spectra

Identification of large-amplitude Alfvénic wave trains lasting about 35 minutes

Evidence that global solar oscillations influence the solar wind

Abstract

The Sun's surface vibrates in characteristic 5-minute oscillations, known as p-modes, generated by sound waves trapped within the convection zone. Although these oscillations have long been hypothesized to reach into the solar wind, direct in situ evidence has remained elusive, even during previous close encounters by Parker Solar Probe (PSP). Here, we present the first promising in situ detection of 5-minute oscillations in the upper solar corona, based on observations from PSP's three closest perihelia. In two events at 9.9 solar radii, we identify statistically significant ($\sim$ 6 $\sigma$) 3.1-3.2 mHz peaks in the magnetic field power spectrum, each appearing as a large-amplitude, spherically polarized Alfv\'enic wave train lasting approximately 35 minutes. These results demonstrate that global solar oscillations can reach and potentially influence the solar wind.