Magnetic Reconnection in the Corona as a Source of Switchbacks in the Solar Wind

Abstract:

The observations from the Parker Solar Probe during the first
perihelion revealed large numbers of local reversals in the radial
component of the magnetic field with associated
velocity spikes. Since the spacecraft was magnetically connected to a
coronal hole during the closest approach to the sun, one possible
source of these spikes is magnetic reconnection between the open field
lines in the coronal hole and an adjacent region of closed
flux. Reconnection in a low beta environment characteristic of the
corona is expected to be bursty rather than steady and is therefore
capable of producing large numbers of magnetic flux ropes with local
reversals of the radial magnetic field that can propagate outward
large radial distances from the sun. Flux ropes with a strong guide
field produce signatures consistent with the PSP observations. We are
carrying out simulations of "interchange" reconnection in the corona
and are exploring the local structure of flux ropes embedded within
the expanding solar wind. We have first established that traditional
interchange reconnection cannot produce the switchbacks since bent
field lines generated in the corona quickly straighten. The
simulations are being extended to the regime dominated by the
production of multiple flux ropes. Local simulations of reconnection
are also being carried out to explore the structure of flux ropes
embedded in the solar wind for comparison with observations.