SH049-0021
The Structure and Origin of Switchbacks: Parker Solar Probe Observations
Wednesday, 16 December 2020
Poster
Jia Huang1, Justin Christophe Kasper2, Lennard A Fisk3, Michael McManus4, J. L. Verniero4, Davin E Larson5, Roberto Livi6, Bennett Maruca7, Ramiz A Qudsi8, Mihailo Martinović9, Kristopher G. Klein9, Daniel Vech10, Mojtaba Akhavan-Tafti11, Michael Louis Stevens12, Anthony W Case12, Kelly E Korreck12, Stuart D Bale4, Phyllis L Whittlesey6, Marc Pulupa6, Thierry Dudok de Wit13, David Malaspina14, Benoit Lavraud15 and Naïs Fargette16, (1)University of Michigan Ann Arbor, Ann Arbor, MI, United States, (2)University of Michigan, Climate and Space Sciences and Engineering, Ann Arbor, MI, United States, (3)Univ Michigan, Ann Arbor, MI, United States, (4)University of California Berkeley, Space Sciences Laboratory, Berkeley, CA, United States, (5)Space Sciences Laboratory, Berkeley, CA, United States, (6)Space Sciences Laboratory, University of California Berkeley, Berkeley, CA, United States, (7)Center for Astrophysics, Berkeley, CA, United States, (8)University of Delaware, Department of Physics and Astronomy, Newark, DE, United States, (9)University of Arizona, Lunar and Planetary Laboratory, Tucson, AZ, United States, (10)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (11)University of Michigan Ann Arbor, Climate and Space Sciences and Engineering, Ann Arbor, MI, United States, (12)Smithsonian Astrophysical Observatory, Cambridge, MA, United States, (13)LPC2E, CNRS and University of Orléans, Orléans, France, (14)University of Colorado, Astrophysical and Planetary Sciences Department, Boulder, CO, United States, (15)IRAP/CNRS, Toulouse, France, (16)IRAP, Toulouse, France
Abstract:
During its initial several orbits of the Sun, Parker Solar Probe (PSP) observed abundant switchbacks, which are characterized by rapid magnetic field polarity reversals. These observations pose many open questions in regards to the nature of switchbacks, for example, how are they generated and how stable are they propagate through the inner heliosphere. In this work, with more than one thousand switchbacks identified with PSP observations in Encounters 1, 2 and 4, we find that switchbacks have many more current-sheet like structures inside than outside, indicating that these micro-structures play an important role to maintain the S-shape structure of switchbacks. The alpha particle to proton abundance ratio (AHe), available during Encounter 4, gives us a compositional diagnostic for investigating their origins. We demonstrate that both helium-rich and helium-poor populations have been observed both inside and outside of the switchbacks, implying that they could originate from both closed and open magnetic field regions. Further analysis of ion differential flows suggest that reconnection may have some role on the fundamental dynamics of switchbacks.
