Solar Radio Bursts Reveal Magnetic Switchbacks Near the Sun

Solar radio bursts provide insights into magnetic field structures near the Sun. Data from the Parker Solar Probe (PSP) suggest that variations in these bursts reveal hidden magnetic switchbacks. These switchbacks are sudden reversals in the direction of the Sun's magnetic field.

Researchers analyzed 24 interplanetary type III bursts observed by the Parker Solar Probe over one week. Type III bursts are radio emissions generated by electron beams streaming along open magnetic field lines. The study converted peak frequencies of these bursts to distances from the Sun.

Fifty percent of the analyzed bursts showed deviations beyond a noise level of 0.57 solar radii. The average displacement observed was 1.1 solar radii. These deviations can be explained by density changes of 10–30% or magnetic field deviations of 23–88 degrees.

These magnetic field deviations occur over spatial scales ranging from 1.8 to 6.4 solar radii. Four of the type III bursts exhibited features consistent with simulations of magnetic field deviations, such as switchbacks. This suggests that magnetic field variations, rather than large density changes, are a more plausible explanation for the observed burst profiles.

These findings indicate that variations in type III burst profiles result from both magnetic and density fluctuations. Type III bursts serve as remote probes for studying the inner heliospheric structure at kilometer wavelengths. The research was published in *The Astrophysical Journal*.