Detection of small magnetic flux ropes from the third and fourth Parker Solar Probe encounters

• Published in: Astronomy and astrophysics (Berlin) 2021-06, Vol.650, p.A12
• Main Authors: Zhao, L.-L., Zank, G. P., Hu, Q., Telloni, D., Chen, Y., Adhikari, L., Nakanotani, M., Kasper, J. C., Huang, J., Bale, S. D., Korreck, K. E., Case, A. W., Stevens, M., Bonnell, J. W., Dudok de Wit, T., Goetz, K., Harvey, P. R., MacDowall, R. J., Malaspina, D. M., Pulupa, M., Larson, D. E., Livi, R., Whittlesey, P., Klein, K. G., Raouafi, N. E.
• Format: Article
• Language: English
• Subjects: Current sheets; Helicity; Magnetic flux; Orbits; Sciences of the Universe; Solar probes; Solar wind; Statistical analysis
• ISSN: 0004-6361; 1432-0746; 1432-0756
• DOI: 10.1051/0004-6361/202039298

Context. Aims. We systematically search for magnetic flux rope structures in the solar wind to within the closest distance to the Sun of ~0.13 AU, using data from the third and fourth orbits of the Parker Solar Probe. Methods. We extended our previous magnetic helicity-based technique of identifying magnetic flux rope structures. The method was improved upon to incorporate the azimuthal flow, which becomes larger as the spacecraft approaches the Sun. Results. A total of 21 and 34 magnetic flux ropes are identified during the third (21-day period) and fourth (17-day period) orbits of the Parker Solar Probe, respectively. We provide a statistical analysis of the identified structures, including their relation to the streamer belt and heliospheric current sheet crossing.