The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe Measurements
In this study we examine the radial dependence of the inertial and dissipation range indices, as well as the spectral break separating the inertial and dissipation range in power density spectra of interplanetary magnetic field fluctuations using Parker Solar Probe data from the fifth solar encounte...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/aca903 |
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| author | S. Lotz A. E. Nel R. T. Wicks O. W. Roberts N. E. Engelbrecht R. D. Strauss G. J. J. Botha E. P. Kontar A. Pitňa S. D. Bale |
| author_facet | S. Lotz A. E. Nel R. T. Wicks O. W. Roberts N. E. Engelbrecht R. D. Strauss G. J. J. Botha E. P. Kontar A. Pitňa S. D. Bale |
| author_sort | S. Lotz |
| collection | DOAJ |
| description | In this study we examine the radial dependence of the inertial and dissipation range indices, as well as the spectral break separating the inertial and dissipation range in power density spectra of interplanetary magnetic field fluctuations using Parker Solar Probe data from the fifth solar encounter between ∼0.1 and ∼0.7 au. The derived break wavenumber compares reasonably well with previous estimates at larger radial distances and is consistent with gyro-resonant damping of Alfvénic fluctuations by thermal protons. We find that the inertial scale power-law index varies between approximately −1.65 and −1.45. This is consistent with either the Kolmogorov (−5/3) or Iroshnikov–Kraichnan (−3/2) values, and has a very weak radial dependence with a possible hint that the spectrum becomes steeper closer to the Sun. The dissipation range power-law index, however, has a clear dependence on radial distance (and turbulence age), decreasing from −3 near 0.7 au (4 days) to −4 [±0.3] at 0.1 au (0.75 days) closer to the Sun. |
| first_indexed | 2024-03-12T03:36:34Z |
| format | Article |
| id | doaj.art-40aac7d5733d4116947242f845b2b9a4 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:36:34Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-40aac7d5733d4116947242f845b2b9a42023-09-03T13:08:35ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194229310.3847/1538-4357/aca903The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe MeasurementsS. Lotz0A. E. Nel1https://orcid.org/0000-0001-6917-1105R. T. Wicks2https://orcid.org/0000-0002-0622-5302O. W. Roberts3https://orcid.org/0000-0002-3913-1353N. E. Engelbrecht4https://orcid.org/0000-0003-3659-7956R. D. Strauss5https://orcid.org/0000-0002-0205-0808G. J. J. Botha6https://orcid.org/0000-0002-5915-697XE. P. Kontar7https://orcid.org/0000-0002-8078-0902A. Pitňa8https://orcid.org/0000-0001-8913-191XS. D. Bale9https://orcid.org/0000-0002-1989-3596South African National Space Agency , Hermanus, 7200, South Africa; MUST, Faculty of Engineering, North-West University , South AfricaSouth African National Space Agency , Hermanus, 7200, South AfricaDepartment of Mathematics, Physics and Electrical Engineering, Northumbria University , Newcastle upon Tyne NE1 8ST, UKSpace Research Institute, Austrian Academy of Sciences , Schmiedlstrasse 6, Graz, A-8042, AustriaCenter for Space Research, North-West University , Potchefstroom, 2522, South Africa ; dutoit.strauss@nwu.ac.za; National Institute for Theoretical and Computational Sciences (NITheCS) , South AfricaCenter for Space Research, North-West University , Potchefstroom, 2522, South Africa ; dutoit.strauss@nwu.ac.za; National Institute for Theoretical and Computational Sciences (NITheCS) , South AfricaDepartment of Mathematics, Physics and Electrical Engineering, Northumbria University , Newcastle upon Tyne NE1 8ST, UKSchool of Physics and Astronomy, University of Glasgow , Glasgow G12 8QQ, UKDepartment of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University , V Holes̆ovic̆kách 2, 180 00 Prague, Czech RepublicPhysics Department, University of California , Berkeley, CA 94720-7300, USA; Space Sciences Laboratory, University of California , Berkeley, CA 94720-7450, USAIn this study we examine the radial dependence of the inertial and dissipation range indices, as well as the spectral break separating the inertial and dissipation range in power density spectra of interplanetary magnetic field fluctuations using Parker Solar Probe data from the fifth solar encounter between ∼0.1 and ∼0.7 au. The derived break wavenumber compares reasonably well with previous estimates at larger radial distances and is consistent with gyro-resonant damping of Alfvénic fluctuations by thermal protons. We find that the inertial scale power-law index varies between approximately −1.65 and −1.45. This is consistent with either the Kolmogorov (−5/3) or Iroshnikov–Kraichnan (−3/2) values, and has a very weak radial dependence with a possible hint that the spectrum becomes steeper closer to the Sun. The dissipation range power-law index, however, has a clear dependence on radial distance (and turbulence age), decreasing from −3 near 0.7 au (4 days) to −4 [±0.3] at 0.1 au (0.75 days) closer to the Sun.https://doi.org/10.3847/1538-4357/aca903Space plasmasSolar windInterplanetary turbulence |
| spellingShingle | S. Lotz A. E. Nel R. T. Wicks O. W. Roberts N. E. Engelbrecht R. D. Strauss G. J. J. Botha E. P. Kontar A. Pitňa S. D. Bale The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe Measurements The Astrophysical Journal Space plasmas Solar wind Interplanetary turbulence |
| title | The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe Measurements |
| title_full | The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe Measurements |
| title_fullStr | The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe Measurements |
| title_full_unstemmed | The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe Measurements |
| title_short | The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe Measurements |
| title_sort | radial variation of the solar wind turbulence spectra near the kinetic break scale from parker solar probe measurements |
| topic | Space plasmas Solar wind Interplanetary turbulence |
| url | https://doi.org/10.3847/1538-4357/aca903 |
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