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

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 have carried out simulations
of "interchange" reconnection in the corona and have explored 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 have been
extended to the regime dominated by the production of multiple flux
ropes and we have established that flux ropes are injected into the
local solar wind. 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. Evidence is presented
that flux rope merging may be ongoing and might lead to the high
aspect ratio of the switchback structures measured in the solar wind.