Correlations between Periodicities in Type III Radio Bursts and Coronal Active Regions

Periodic processes and their effects are ever-present in the heliosphere. Several studies have identified simultaneous quasi-periodic behavior in radio waves, microwaves, x-rays, and EUV with periods of minutes, comparable to those of helio-seismological modes. Initial comparisons of the periodicities in Type III radio bursts observed by Parker Solar Probe and in EUV data from SDO/AIA at times with no observable flares suggested that the electron acceleration producing Type III bursts was due to small, short-lived events, such as nanoflares. We present results from a study of additional events with the goal of further assessing quasi-periodic behavior in solar Type III radio emissions observed by PSP and its link to simultaneous EUV observations of active regions. We intercompare the results of wavelet analysis, Fast Fourier Transforms (FFTs), and a peak finder approach to verify and quantify the quasi-periodic behavior. We have determined the presence of periodicities between 4 and 8 minutes in radio wave power measured at 13.3 solar radii by the FIELDS Radio Frequency Spectrometer onboard PSP during a number of intervals from the recent Encounter 14, in addition to earlier encounters. These results often agree well with the periodicities found in concurrent EUV data for specific wavelengths and sub-regions of the active region most likely to be associated with the Type III bursts observed by PSP. Our findings provide additional evidence that impulsive acceleration of electrons producing Type III radio bursts is sometimes quasi-periodic, with periods on the order of minutes. This is consistent with theories suggesting that solar P-modes can modulate reconnection in the corona.