English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Parker Solar Probe (PSP) observations during its first encounter at 35.7$R_\odot$ have shown the presence of magnetic field lines which are stronglyperturbed to the point that they produce local inversions of the radialmagnetic field, known as switchbacks. Their counterparts in the solar windvelocity field are local enhancements in the radial speed, or jets, displaying(in all components) the velocity-magnetic field correlation typical of largeamplitude Alfv\'en waves propagating away from the Sun. Switchbacks and radialjets have previously been observed over a wide range of heliocentric distancesby Helios, WIND and Ulysses, although they were prevalent in significantlyfaster streams than seen at PSP. Here we study via numerical MHD simulationsthe evolution of such large amplitude Alfv\'enic fluctuations by including, inagreement with observations, both a radial magnetic field inversion and aninitially constant total magnetic pressure. Despite the extremely largeexcursion of magnetic and velocity fields, switchbacks are seen to persist forup to hundreds of Alfv\'en crossing times before eventually decaying due to theparametric decay instability. Our results suggest that such switchback/jetconfigurations might indeed originate in the lower corona and survive out toPSP distances, provided the background solar wind is sufficiently calm, in thesense of not being pervaded by strong density fluctuations or other gradients,such as stream or magnetic field shears, that might destabilize or destroy themover shorter timescales.

Magnetic field kinks and folds in the solar wind