학술논문
Magnetic field spectral evolution in the inner heliosphere
Document Type
Working Paper
Author
Sioulas, Nikos; Huang, Zesen; Shi, Chen; Velli, Marco; Tenerani, Anna; Vlahos, Loukas; Bowen, Trevor A.; Bale, Stuart D.; Bonnell, J. W.; Harvey, P. R.; Larson, Davin; Pulupa, arc; Livi, Roberto; Woodham, L. D.; Horbury, T. S.; Stevens, Michael L.; de Wit, T. Dudok; MacDowall, R. J.; Malaspina, David M.; Goetz, K.; Huang, Jia; Kasper, Justin; Owen, Christopher J.; Maksimović, Milan; Louarn, P.; Fedorov, A.
Source
Subject
Language
Abstract
Parker Solar Probe and Solar Orbiter data are used to investigate the radial evolution of magnetic turbulence between $0.06 ~ \lesssim R ~\lesssim 1$ au. The spectrum is studied as a function of scale, normalized to the ion inertial scale $d_{i}$. In the vicinity of the Sun, the inertial range is limited to a narrow range of scales and exhibits a power-law exponent of, $\alpha_{B} = -3/2$, independent of plasma parameters. The inertial range grows with distance, progressively extending to larger spatial scales, while steepening towards a $\alpha_{B} =-5/3$ scaling. It is observed that spectra for intervals with large magnetic energy excesses and low Alfv\'enic content steepen significantly with distance, in contrast to highly Alfv\'enic intervals that retain their near-Sun scaling. The occurrence of steeper spectra in slower wind streams may be attributed to the observed positive correlation between solar wind speed and Alfv\'enicity.
Comment: Accepted to APJ letters with minor revisions
Comment: Accepted to APJ letters with minor revisions