Radial Dependence of the Magnetic Turbulence at Transition and Kinetic Range in the Inner Heliosphere

D. Duan , T. A. Bowen , J. He , A. Mallet , S. D. Bale , J. W. Bonnell , A. W. Case , Thierry Dudok de Wit (1) , K. Goetz , J. C. Kasper , K. E. Korreck , P. Harvey , D. E. Larson , R. J. Macdowall , D. Malaspina , M. Pulupa , M. L. Stevens , P. L. Whittlesey

1 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

Magnetohydodynamic range turbulent magnetic fluctuations in the solar wind are typically observed with a Kolmogorov spectral scaling k^(-5/3). At smaller scales, kinetic effects cause the spectrum to steepen. We present a statistical study of the kinetic-scale turbulence using measurements from the PSP/FIELDS fluxgate and search coil magnetometers in the inner heliosphere (0.16 -0.30 AU). At kinetic scales a spectrum of -8/3 is measured; however, we show that a transition range between magnetohydrodynamic and kinetic scales is commonly observed. Analysis of the radial scaling shows that the both transition and kinetic range spectrum becomes steeper and more pronounced closer to the sun.

Mots clés: Interplanetary magnetic fields; INTERPLANETARY PHYSICS; MHD waves and turbulence; Solar wind plasma; Kinetic and MHD theory; SPACE PLASMA PHYSICS; Nonlinear phenomena; Turbulence

Domaines: Planète et Univers [physics]

D. Duan, T. A. Bowen, J. He, A. Mallet, S. D. Bale, et al.. Radial Dependence of the Magnetic Turbulence at Transition and Kinetic Range in the Inner Heliosphere. American Geophysical Union, 2020, Online, France. ⟨insu-03560376⟩