Resonant Alfvén Waves in the Lower Auroral Ionosphere: Evidence for the Nonlinear Evolution of the Ionospheric Feedback Instability

Akbari, H.; Pfaff, R. F.; Clemmons, J. H.; Freudenreich, H.; Rowland, D. E.; Streltsov, A. V.

doi:10.1029/2021ja029854

Cited by 4 publications

(3 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As typical (e.g., SM18), the IFI creates in both hemispheres a system of intense small‐scale FACs, with downward currents ( j ↓ ) dominating their upward ( j ↑ ) counterparts. The current intensities of the order of 50–80 μA/m 2 are comparable to those observed in the auroral ionosphere (e.g., Akbari et al., 2022).…”

Section: Ionospheric Feedback Instability In Strong Saidsupporting

confidence: 78%

On the Kinetic Theory of Subauroral Arcs

Mishin

Streltsov

2022

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

We report on a novel scenario of subauroral arcs within strong subauroral ion drifts (SAID)‐STEVE and Picket Fence. Their explanation requires a local source of low‐energy, ε < 18.75 eV, suprathermal electrons, and N2 vibrational and electronic excitation below ∼270 km. We show that the ionospheric feedback instability in strong SAID flows with depleted density troughs generates intense, small‐scale field‐aligned currents and parallel electric fields below the F2 peak. With these fields, we employed a rigorous numerical solution of the Boltzmann kinetic equation for the distribution of ionospheric electrons and determined the power going to excitation and ionization of neutral gas (the energy balance). The obtained suprathermal electron population and energy balance at altitudes of ∼130–140 km are just what is necessary for Picket Fence. Concerning STEVE, the kinetic theory predictions are in a good qualitative agreement with its basic features, such as the enhanced continuum emissions. Besides, the theory predicts that subauroral arcs might have the transient phase with typical aurora‐like emissions that fade out afterward.

show abstract

Section: Ionospheric Feedback Instability In Strong Saidsupporting

confidence: 78%

On the Kinetic Theory of Subauroral Arcs

Mishin

Streltsov

2022

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…The first conclusion from Figure 3c is that the amplitude of the intensity of FACs generated by the IFI saturates during 1,600 s at the amplitude of ≈30 μA/m 2 . These are relatively large currents, but they have been observed on low‐orbiting satellites and sounding rockets at high latitudes, for example, (Akbari et al., 2022).…”

Section: Resultsmentioning

confidence: 99%

Ionospheric Feedback and ULF Quarter‐Waves

Streltsov

Mishin

2022

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

The combination of nonlinear interactions between the magnetospheric field-aligned currents (FACs) and the ionospheric plasma is one of the main mechanisms defining the dynamics, structure, and amplitude of ULF electromagnetic waves and small-scale density structures in the near-Earth space at auroral and subauroral latitudes. The essence of these interactions can be explained as an active ionospheric response to the structure and amplitude of FACs, changing ionospheric conductivity by precipitating and removing electrons from the ionosphere. The change in the conductivity changes the reflection coefficient of the waves and the dissipation of the energy of the large-scale electric field normally existing in the high-latitude ionosphere.The upward FACs precipitate electrons in the ionosphere and locally increase the ionospheric conductivity. The increase in the conductivity increases the amplitude of the reflected currents and decreases the dissipation of the large-scale electric field in the ionosphere, which, in turn, generates additional upward FACs. Thus, when the geophysical conditions are favorable, the ionosphere provides a positive, constructive feedback on the amplitude of FACs interacting with it. And if this current is trapped in some magnetospheric resonator with at least one boundary on the ionosphere, then the positive feedback may lead to the development of a so-called ionospheric feedback instability (IFI).The basic concept of IFI has been introduced by Atkinson (1970) and extensively studied after that in the global magnetospheric resonator and the ionospheric Alfvén resonator (IAR)

show abstract

“…the F-region and above), the recent Auroral Jets rockets identified resonant Alfvén waves within the ionosphere, including to altitudes as low as 150 km (e.g. Akbari et al, 2022). Likewise, there is a significant population of auroral forms in subkilometer spatial scales ( 0.1-1 km) (Partamies et al, 2010).…”

Section: Importance Of Small Scalesmentioning

confidence: 99%

Understanding the Transfer of Electromagnetic Energy Between the Earth’s Magnetosphere and Upper Atmosphere

Chartier,

Matsuo,

Perry

et al. 2023

Bulletin of the AAS

View full text Add to dashboard Cite

Electromagnetic energy is likely the largest unknown input to the upper atmosphere. Together with precipitating particles, it may constitute the largest overall source of energy during geomagnetic storms. This source of energy is a critical driver of stormtime dynamics, and is responsible for plasma convection, atmospheric upwelling in the cusps, as well as many other important phenomena. The net transfer of electromagnetic energy between the magnetosphere and upper atmosphere can be quantified in terms of "Poynting flux" as observed between ~400-1000 km (above the collisional ionosphere and below the magnetospheric acceleration region). This source of energy is highly variable both spatially and temporally, and so its accurate characterization would require a very large number of measurements. Statistical estimates of Poynting flux based on groundbased and satellite data can differ by an order of magnitude overall, and show contrasting morphologies. There are indications that small-scale phenomena contribute a large fraction of the total energy, especially at higher altitudes, though recent data on this subject are scarce due to the absence of E-field probe data at the relevant altitudes. Recent analysis of data from several missions by three different groups indicates a major ~30% asymmetry in the Poynting flux, favoring the Northern hemisphere. The Poynting vector is occasionally observed to point upward, indicating a net transfer of energy from the atmosphere to the magnetosphere. These cases may hold the key to unraveling poorly understood magnetosphere-ionosphere coupling phenomena. Recent major advances in modeling from the ground up to 600-km and, separately, from the solar wind down to the ionosphere (e.g. GAMERA, BATS-R-US) essentially meet here, and so this topic is a compelling target for both modelers and observationalists.

show abstract

Resonant Alfvén Waves in the Lower Auroral Ionosphere: Evidence for the Nonlinear Evolution of the Ionospheric Feedback Instability

Cited by 4 publications

References 33 publications

On the Kinetic Theory of Subauroral Arcs

On the Kinetic Theory of Subauroral Arcs

Ionospheric Feedback and ULF Quarter‐Waves

Understanding the Transfer of Electromagnetic Energy Between the Earth’s Magnetosphere and Upper Atmosphere

Contact Info

Product

Resources

About