Abstract Details
| 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 and Co-Authors : Karan SAHU 1, Susanta K. BISOI 1 and Shreekrushna MISHRA1 Abstract Type : 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. |