Switchbacks as signatures of magnetic flux ropes generated by interchange reconnection in the corona

¹ Department of Physics, the Institute for Physical Science and Technology and the Joint Space Institute, University of Maryland, College Park, MD, USA
e-mail: drake@umd.edu
² Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, USA
³ Space Sciences Laboratory, University of California Berkeley, Berkeley, CA, USA
⁴ The Blackett Laboratory, Imperial College London, London, UK
⁵ BWX Technologies, Inc., Washington DC, USA
⁶ Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
⁷ Code 695 NASA Goddard Space Flight Center, Greenbelt, MD, USA
⁸ Code 672 NASA Goddard Space Flight Center, Greenbelt, MD, USA
⁹ Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA

Received: 14 September 2020
Accepted: 8 October 2020

Abstract

The structure of magnetic flux ropes injected into the solar wind during reconnection in the coronal atmosphere is explored with particle-in-cell simulations and compared with in situ measurements of magnetic “switchbacks” from the Parker Solar Probe. We suggest that multi-x-line reconnection between open and closed flux in the corona injects flux ropes into the solar wind and that these flux ropes convect outward over long distances before eroding due to reconnection. Simulations that explore the magnetic structure of flux ropes in the solar wind reproduce the following key features of the switchback observations: a rapid rotation of the radial magnetic field into the transverse direction, which is a consequence of reconnection with a strong guide field; and the potential to reverse the radial field component. The potential implication of the injection of large numbers of flux ropes in the coronal atmosphere for understanding the generation of the solar wind is discussed.