| Title: |
The Evolution of the 1/f Range within a Single Fast-solar-wind Stream between 17.4 and 45.7 Solar Radii |
| Authors: |
Davis, Nooshin; Chandran, B. D. G.; Bowen, T. A.; Badman, S. T.; Dudok de Wit, Thierry; Chen, C. H. K.; Bale, S. D.; Huang, Zesen; Sioulas, Nikos; Velli, Marco |
| Contributors: |
University of New Hampshire (UNH); Space Sciences Laboratory Berkeley (SSL); University of California Berkeley (UC Berkeley); University of California (UC)-University of California (UC); Harvard University; Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E); Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales Paris (CNES); International Space Science Institute Bern (ISSI) |
| Source: |
ISSN: 0004-637X. |
| Publisher Information: |
CCSD; American Astronomical Society |
| Publication Year: |
2023 |
| Collection: |
Université d'Orléans: HAL |
| Subject Terms: |
Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Interplanetary turbulence; Solar wind; Magnetohydrodynamics; [SDU]Sciences of the Universe [physics] |
| Description: |
International audience ; The power spectrum of magnetic field fluctuations in the fast solar wind (V SW > 500 km s -1 ) at magnetohydrodynamic scales is characterized by two different power laws on either side of a break frequency f b . The low-frequency range at frequencies f smaller than f b is often viewed as the energy reservoir that feeds the turbulent cascade at f > f b . At heliocentric distances r exceeding 60 solar radii (R s ), the power spectrum often has a 1/f scaling at f < f b , i.e., the spectral index is close to -1. In this study, measurements from the Parker Solar Probe's Encounter 10 with the Sun are used to investigate the evolution of the magnetic field power spectrum at f < f b at r < 60 R s during a fast radial scan of a single fast-solar-wind stream. We find that the spectral index in the low-frequency part of the spectrum decreases from approximately -0.61 to -0.94 as r increases from 17.4 to 45.7 R s . Our results suggest that the 1/f spectrum that is often seen at large r in the fast solar wind is not produced at the Sun, but instead develops dynamically as the wind expands outward from the corona into the interplanetary medium. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
info:eu-repo/semantics/altIdentifier/arxiv/2303.01663; ARXIV: 2303.01663; BIBCODE: 2023ApJ.950.154D |
| DOI: |
10.3847/1538-4357/acd177 |
| Availability: |
https://insu.hal.science/insu-04151713; https://insu.hal.science/insu-04151713v1/document; https://insu.hal.science/insu-04151713v1/file/Davis_2023_ApJ_950_154.pdf; https://doi.org/10.3847/1538-4357/acd177 |
| Rights: |
http://creativecommons.org/licenses/by/ ; info:eu-repo/semantics/OpenAccess |
| Accession Number: |
edsbas.A3E6A4B0 |
| Database: |
BASE |