On the stability and evolution of switchbacks in the solar wind
Abstract
Large amplitude, turbulent Alfvénic fluctuations have been commonly observed in the solar wind since the first in-situ measurements, and they are thought to provide a possible mechanism to heat the solar corona and accelerate the solar wind. An important property that remains to be explained is that these fluctuations display a high degree of coherence that manifests itself not just via the velocity-magnetic field correlation that characterizes Alfvé n waves propagating away from the sun, but also via the observed high degree of plasma incompressibility. In this context, the recent measurements from Parker Solar Probe (PSP) have revealed the ubiquitous and persistent presence of such Alfvénic fluctuations where the magnetic field lines are so strongly perturbed to the point that they produce local inversions of the radial magnetic field, known as switchbacks. While there is not yet a general consensus on what is the origin of switchbacks and their connection to coronal activity, a first necessary step to answer these important questions is to understand how they evolve and how long they can persist in the solar wind. Here w e investigate the evolution of switchbacks via numerical MHD simulations by including, in agreement with observations, both a radial magnetic field inversion and an initially constant total magnetic field pressure. We address in particular how the evolution of switchbacks is affected by parametric instabilities and expansion effects, and we finally discuss what are the implications of our results for models of switchback generation.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMSH055..04T
- Keywords:
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- 7509 Corona;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7526 Magnetic reconnection;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7829 Kinetic waves and instabilities;
- SPACE PLASMA PHYSICS;
- 7863 Turbulence;
- SPACE PLASMA PHYSICS