Conditions for the Kelvin‐Helmholtz Instability in the Polar Ionosphere
Abstract The Kelvin‐Helmholtz instability can be excited by a velocity shear in a fluid. Inhomogeneous flows are frequently observed in regions with polar cap patches, reversed flow events and auroral arcs, that is, regions with irregularities that disturb navigation satellite signals. Understanding...
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| Format: | Article |
| Language: | English |
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Wiley
2025-03-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2025GL114621 |
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| _version_ | 1850187532563644416 |
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| author | Andreas Kvammen Andres Spicher Matthew Zettergren Devin Huyghebaert Theresa Rexer Björn Gustavsson Juha Vierinen |
| author_facet | Andreas Kvammen Andres Spicher Matthew Zettergren Devin Huyghebaert Theresa Rexer Björn Gustavsson Juha Vierinen |
| author_sort | Andreas Kvammen |
| collection | DOAJ |
| description | Abstract The Kelvin‐Helmholtz instability can be excited by a velocity shear in a fluid. Inhomogeneous flows are frequently observed in regions with polar cap patches, reversed flow events and auroral arcs, that is, regions with irregularities that disturb navigation satellite signals. Understanding the driving conditions and the evolution of the instability is therefore important. In this work, we simulate a flow shear and analyze the non‐linear instability development for a range of velocity shear strengths, shear widths and electron densities. The simulations show that Kelvin‐Helmholtz instability structures can form within 2 minutes for high‐velocity shears (Δv≥1.8 km/s) and low shear widths (ℓ≤2 km), while auroral precipitation dampens instability development. We propose an empirical function for the relationship between instability growth and initial conditions. These results can be used to interpret observations of turbulent flow shear conditions. |
| format | Article |
| id | doaj-art-4e8500068a9b40109eab94df6ecec986 |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-4e8500068a9b40109eab94df6ecec9862025-08-20T02:16:05ZengWileyGeophysical Research Letters0094-82761944-80072025-03-01525n/an/a10.1029/2025GL114621Conditions for the Kelvin‐Helmholtz Instability in the Polar IonosphereAndreas Kvammen0Andres Spicher1Matthew Zettergren2Devin Huyghebaert3Theresa Rexer4Björn Gustavsson5Juha Vierinen6Department of Physics and Technology UiT—The Arctic University of Norway Tromsø NorwayDepartment of Physics and Technology UiT—The Arctic University of Norway Tromsø NorwayDepartment of Physical Sciences and Center for Space and Atmospheric Research (CSAR) Embry‐Riddle Aeronautical University Daytona Beach FL USADepartment of Physics and Technology UiT—The Arctic University of Norway Tromsø NorwayDepartment of Physics and Technology UiT—The Arctic University of Norway Tromsø NorwayDepartment of Physics and Technology UiT—The Arctic University of Norway Tromsø NorwayDepartment of Physics and Technology UiT—The Arctic University of Norway Tromsø NorwayAbstract The Kelvin‐Helmholtz instability can be excited by a velocity shear in a fluid. Inhomogeneous flows are frequently observed in regions with polar cap patches, reversed flow events and auroral arcs, that is, regions with irregularities that disturb navigation satellite signals. Understanding the driving conditions and the evolution of the instability is therefore important. In this work, we simulate a flow shear and analyze the non‐linear instability development for a range of velocity shear strengths, shear widths and electron densities. The simulations show that Kelvin‐Helmholtz instability structures can form within 2 minutes for high‐velocity shears (Δv≥1.8 km/s) and low shear widths (ℓ≤2 km), while auroral precipitation dampens instability development. We propose an empirical function for the relationship between instability growth and initial conditions. These results can be used to interpret observations of turbulent flow shear conditions.https://doi.org/10.1029/2025GL114621Kelvin‐Helmholtz instabilityplasma fluid simulationionospheric flow shearionospheric turbulenceirregularity formationnon‐linear instability evolution |
| spellingShingle | Andreas Kvammen Andres Spicher Matthew Zettergren Devin Huyghebaert Theresa Rexer Björn Gustavsson Juha Vierinen Conditions for the Kelvin‐Helmholtz Instability in the Polar Ionosphere Geophysical Research Letters Kelvin‐Helmholtz instability plasma fluid simulation ionospheric flow shear ionospheric turbulence irregularity formation non‐linear instability evolution |
| title | Conditions for the Kelvin‐Helmholtz Instability in the Polar Ionosphere |
| title_full | Conditions for the Kelvin‐Helmholtz Instability in the Polar Ionosphere |
| title_fullStr | Conditions for the Kelvin‐Helmholtz Instability in the Polar Ionosphere |
| title_full_unstemmed | Conditions for the Kelvin‐Helmholtz Instability in the Polar Ionosphere |
| title_short | Conditions for the Kelvin‐Helmholtz Instability in the Polar Ionosphere |
| title_sort | conditions for the kelvin helmholtz instability in the polar ionosphere |
| topic | Kelvin‐Helmholtz instability plasma fluid simulation ionospheric flow shear ionospheric turbulence irregularity formation non‐linear instability evolution |
| url | https://doi.org/10.1029/2025GL114621 |
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