Inhomogeneous Kinetic Alfven Waves in the Near-Sun Solar Wind

David M. Malaspina; Alexandros Chasapis; Peter Tatum; Chadi Salem; Stuart D. Bale; John W. Bonnell; Thierry Dudok de Wit; Keith Goetz; Marc Pulupa; Jasper Halekas; Phyllis Whittlesey; Roberto Livi; Anthony W. Case; Michael L. Stevens; Davin Larson

doi:10.3847/1538-4357/ac87a7

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Inhomogeneous Kinetic Alfven Waves in the Near-Sun Solar Wind

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Inhomogeneous Kinetic Alfven Waves in the Near-Sun Solar Wind

David M. Malaspina, Alexandros Chasapis, Peter Tatum, Chadi Salem, Stuart D. Bale, John W. Bonnell, Thierry Dudok de Wit, Keith Goetz, Marc Pulupa, Jasper Halekas, …

The Astrophysical journal, Vol.936(2), p.128

09/01/2022

DOI: 10.3847/1538-4357/ac87a7

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Abstract

Intervals of intense electromagnetic, broadband plasma waves are reported in the near-Sun solar wind. These waves are identified as kinetic Alfven waves (KAWs), based on comparison between data and theory for their observed electric- to magnetic-field ratio, and magnetic compressibility, as a function of frequency. In contrast to KAW observations at 1 au, KAWs in the near-Sun solar wind are found to be spatially inhomogeneous, preferentially occurring where the ambient magnetic field experiences strong deviations from the Parker spiral direction, including during magnetic switchbacks and clusters of switchbacks. To the extent that turbulent fluctuations in the solar wind at small scales are characterized as KAWs, the observations reported here create an expectation that KAW-driven particle heating should also be inhomogeneous in the near-Sun solar wind, being strongest in regions of intense KAWs. Finally, a discrepancy between KAW observation and theory is identified at frequencies two decades above the frequency where kinetic effects begin to manifest, and possible origins of this discrepancy are considered.

Astronomy & Astrophysics

Physical Sciences

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Details

Title: Subtitle: Inhomogeneous Kinetic Alfven Waves in the Near-Sun Solar Wind
Creators: David M. Malaspina - Laboratory for Atmospheric and Space Physics
Alexandros Chasapis - Laboratory for Atmospheric and Space Physics
Peter Tatum - Laboratory for Atmospheric and Space Physics
Chadi Salem - University of California, Berkeley
Stuart D. Bale - University of California, Berkeley
John W. Bonnell - University of California, Berkeley
Thierry Dudok de Wit - CNES, CNRS, LPC2E, 3A Ave Rech Sci, F-45071 Orleans, France
Keith Goetz - University of Minnesota
Marc Pulupa - University of California, Berkeley
Jasper Halekas - University of Iowa
Phyllis Whittlesey - University of California, Berkeley
Roberto Livi - University of California, Berkeley
Anthony W. Case - Center for Astrophysics Harvard & Smithsonian
Michael L. Stevens - Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA
Davin Larson - University of California, Berkeley
Resource Type: Journal article
Publication Details: The Astrophysical journal, Vol.936(2), p.128
DOI: 10.3847/1538-4357/ac87a7
ISSN: 0004-637X
eISSN: 1538-4357
Publisher: IOP Publishing Ltd
Number of pages: 10
Grant note: NNN06AA01C / NASA's Living with a Star (LWS) program CNES; Centre National D'etudes Spatiales
Language: English
Date published: 09/01/2022
Academic Unit: Physics and Astronomy
Record Identifier: 9984428663102771

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