Geophysical Research Letters· 2026Q1
Convective Amplification of Ionospheric Feedback by a Finite‐Duration Inertial Alfvén‐Wave Source
- 1citations
- Q1SCImago
- 2026year
Short summary
A new Green's-function model shows that finite-duration inertial Alfvén waves can cause convective amplification of ionospheric feedback instability, leading to peak field-aligned currents several times larger than forced values.
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Key points
- A causal Green's-function formulation is derived for a height-integrated ionospheric sheet coupled to an inertial Alfvén cavity.
- Finite-width sources lead to convective amplification of temporal growth in the ionospheric feedback instability.
- The gain of this amplification depends on integrated feedback drive, upper-boundary leakage, and ionospheric relaxation.
- Peak field-aligned currents can be several times larger than values driven solely by external forcing.
AI-generated from the title and abstract; the full text is not read.
Abstract
Abstract We investigate the ionospheric feedback instability (IFI) driven by a finite‐duration localized source of inertial Alfvén waves. Wave‐excited conductance perturbations undergo Pedersen mobility drift in the convection and wave electric fields and are amplified. A causal Green's‐function formulation is derived for a height‐integrated ionospheric sheet coupled to an inertial Alfvén cavity with upper‐boundary reflection. For a finite‐width source, temporal growth becomes convective amplification. The relative phase slip between the returning wave and conductance perturbation provides an a posteriori coherence timescale for evaluating the finite‐source gain. The gain is controlled by time‐integrated feedback drive minus upper‐boundary leakage and ionospheric relaxation. The complex root of the closed dispersion relation determines the wave frequency, growth rate, and packet speed. In one example, the peak field‐aligned current is several times the forced‐only value. Observability depends on phase coherence, losses, transverse escape, and instrumental sampling.
The authors' abstract, as published at the source. Geophysical Research Letters, 2026 · DOI ↗
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Field: Astronomy and Astrophysics
Astronomy and AstrophysicsPhysics and Astronomy