Switchbacks in the Near-Sun Magnetic Field: Long Memory and Impact on the Turbulence Cascade

Thierry Dudok de Wit (1) , Vladimir Krasnoselskikh (1) , Stuart Bale (2) , John Bonnell (2) , Trevor Bowen (2) , Christopher Chen (3) , Clara Froment (1) , Keith Goetz , Peter Harvey , Vamsee Krishna Jagarlamudi (1) , Andrea Larosa , Robert Macdowall , David Malaspina , William Matthaeus , Marc Pulupa , Marco Velli , Phyllis Whittlesey

1 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
2 UC Berkeley - University of California [Berkeley]
3 QMUL - Queen Mary University of London

One of the most striking observations made by Parker Solar Probe during its first solar encounter is the omnipresence of rapid polarity reversals in a magnetic field that is otherwise mostly radial. These so-called switchbacks strongly affect the dynamics of the magnetic field. We concentrate here on their macroscopic properties. First, we find that these structures are self-similar, and have neither a characteristic magnitude, nor a characteristic duration. Their waiting time statistics show evidence of aggregation. The associated long memory resides in their occurrence rate, and is not inherent to the background fluctuations. Interestingly, the spectral properties of inertial range turbulence differ inside and outside of switchback structures; in the latter the 1/f range extends to higher frequencies. These results suggest that outside of these structures we are in the presence of lower-amplitude fluctuations with a shorter turbulent inertial range. We conjecture that these correspond to a pristine solar wind.

Domains: Sciences of the Universe [physics]

Thierry Dudok de Wit, Vladimir Krasnoselskikh, Stuart Bale, John Bonnell, Trevor Bowen, et al.. Switchbacks in the Near-Sun Magnetic Field: Long Memory and Impact on the Turbulence Cascade. The Astrophysical Journal Supplement, 2020, 246 (2), pp.39. ⟨10.3847/1538-4365/ab5853⟩. ⟨insu-02937575⟩