| Name: | Karan Sahu |
| Affiliation: | National Institiute of Technology, Rourkela |
| Conference ID: | ASI2025_177 |
| Title: | Solar coronal origin of solar wind periodic proton number density structures using PSP and STEREO Observations |
| Authors: | Karan SAHU 1, Susanta K. BISOI 1 and Shreekrushna MISHRA1
|
| Authors Affiliation: | 1 Department of Physics and Astronomy, National Institute of Technology, Rourkela -769008, India |
| Mode of Presentation: | Poster |
| Abstract Category: | Sun, Solar System, Exoplanets, and Astrobiology |
| Abstract: | Observation of solar wind at 1 AU reveals discrete variations in its proton number density
that occur periodically and more frequently at particular temporal or radial length scales, re-
ferred to as periodic density structures (PDS). The PDS originate locally in the interplanetary
medium near 1 AU by different dynamic processes, or they can originate in the solar corona
and be convected outward to 1 AU. Earlier studies utilizing in-situ measurements of the solar
wind at 1 AU found PDS to be associated more often with slow (undisturbed) solar wind(speed
< 500 km/s) than fast. In combination with remote imaging solar corona observations, PDS is
suggested to have originated from the Corona. Here, we conducted a case study of four PDS
events to investigate the origin of PDS associated with the slow solar wind, observed at L1 by
Wind spacecraft between 2019-2023 when near-Sun Parker’s Solar Probe (PSP) observations
were available and encountered the same slow solar wind stream as Earth. The slow solar wind
is less turbulent, and the plasma density parcels remain unchanged with the radial distance dur-
ing their transit to 1 AU. Thus, when analyzed using the PSP observations and cross-correlated
with the near-Earth PDS, the corresponding PDS near the Sun showed a strong correlation. Us-
ing a Fourier spectral analysis, common periodicities of a few minutes were found in solar wind
proton densities measured by PSP (near-Sun) and Wind (near-Earth). Further, with the remote
imaging observations of the PDS from STEREO-A, we confirmed that the events originated in
the solar corona, then frozen in the solar wind, and finally convected out to 1 AU. |
