Two-dimensional MHD modelling of switchbacks from jetlets in the slow solar wind

Abstract

Solar wind switchbacks are polarity reversals of the magnetic field, recently frequently measured by Parker Solar Probe inside 0.2 AU. In this Letter we show that magnetic switchbacks, similar to those observed by PSP, are reproduced by injecting a time-limited collimated high-speed stream in the Parker spiral. We performed a 2D magnetohydrodynamics simulation with the PLUTO code of a slightly inclined jet at 1000 km s-1 between 5 and 60 RO. The jet rapidly develops a field inversion at its wings and, at the same time, it is bent by the Parker spiral. The match with the radial outward wind field creates two asymmetric switchbacks, one that bends to the anti-clockwise and one that bends to the clockwise direction in the ecliptic plane, with the last one being the most extended. The simulation shows that such S-shaped magnetic features travel with the jet and persist for several hours and to large distances from the Sun (beyond 20 RO). We show the evolution of physical quantities as they would be measured by a hypothetical detector at a fixed position when crossed by the switchback, for comparison with in situ measurements.