SH049-0012
Observed Turbulent Properties of Spherically Polarized Alfvénic States

Wednesday, 16 December 2020
Poster
Trevor Bowen1, Samuel Timothy Badman1, Stuart D Bale2, Benjamin D G Chandran3, Christopher H K Chen4, Thierry Dudok de Wit5, Timothy Simon Horbury6, Justin Christophe Kasper7, Kristopher G. Klein8, Davin Larson9, Alfred Mallet10, Lorenzo Matteini11, Michael McManus2, Anna Tenerani12, Marco C M Velli13 and J. L. Verniero2, (1)University of California Berkeley, Berkeley, CA, United States, (2)University of California Berkeley, Space Sciences Laboratory, Berkeley, CA, United States, (3)University of New Hampshire, Durham, NH, United States, (4)Queen Mary University of London, School of Physics and Astronomy, London, United Kingdom, (5)LPC2E, CNRS and University of Orléans, Orléans, France, (6)Imperial College London, Department of Physics, London, SW7, United Kingdom, (7)University of Michigan, Climate and Space Sciences and Engineering, Ann Arbor, MI, United States, (8)University of Arizona, Lunar and Planetary Laboratory, Tucson, AZ, United States, (9)Space Sciences Laboratory, University of California Berkeley, Berkeley, CA, United States, (10)University of California Berkeley, Walnut CREEK, CA, United States, (11)Imperial College London, Department of Physics, London, United Kingdom, (12)University of Texas, Austin, TX, United States, (13)University of California Los Angeles, Los Angeles, CA, United States
Abstract:
Observation of large scale Alfvénic "switchbacks" of the inner-heliospheric magnetic field, made by Parker Solar Probe, leads to renewed interest in the nonlinear dynamics of constant magnitude and spherically polarized states in MHD. Analysis of high cross helicity streams studied by PSP shows that the turbulent fluctuations are largely consistent with outward propagating spherically polarized Alfvén waves. It is well known that such waves are an exact solution to the MHD equations. In this work, we explore the turbulent scaling properties of outward propagating spherically polarized Alfvén waves using an increment analysis of rotation angles of the dominant Elsasser mode. We show the connection between spherical symmetry and the outer scale (1/f) turbulent spectrum. The effects of spherical polarization on the sub-dominant (inward propagating) Alfvén waves, compressive fluctuations are discussed, as well as implications for the generation of solar wind turbulence and magnetic switchbacks.
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