Response of the ionosphere–thermosphere system to magnetospheric processes

Schunk, R. W.; Zhu, L.

doi:10.1016/j.jastp.2008.07.003

Cited by 5 publications

(4 citation statements)

References 39 publications

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“…These greater concentrations extend over the surrounding regions of the cyclonic and anticyclonic vortices. The general atomic oxygen depletion over the high-latitude wind convection pattern has been recognized in other studies (Lühr et al, 2004;Schunk & Zhu, 2008;Volland, 1979). Based on these studies and in agreement with what is shown in Figures 9c, 9d, 9g, and 9h, it can be determined that the general atomic oxygen depletion is related to a general upwelling pattern along the line of convection (especially over the departure area), mainly above 120 km.…”

Section: The Wind Wall Impact On the Lower Thermosphere And Its Structuresupporting

confidence: 89%

“…

The thermosphere has a strong variability, which is especially true at high latitudes, where, in addition to the solar EUV and UV radiation, magnetosphere electric fields, particle precipitation, field-aligned currents, heat flows, and ion and neutral escape fluxes also affect the ionosphere-thermosphere system at high latitudes (Schunk & Zhu, 2008). Since the ionosphere is embedded in the thermosphere, continuous interactions between ion and neutral flows occur in this region of the atmosphere.

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confidence: 99%

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Observations and Modeling of Strong Thermospheric Winds at High Latitudes and Their Impact on the Lower Thermosphere

et al. 2021

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A strong westward wind pattern at altitudes of ∼140–250 km at high latitudes (∼65°) in the approximate longitude range of 100°E–200°E in the Southern Hemisphere, and from 200°E to 300°E in the Northern Hemisphere, known as a “wind wall,” is investigated. Simulations from the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM‐X) and the Global Airglow (GLOW) model, along with Wind Imaging Interferometer (WINDII) observations, allowed the description of most of the wind wall features. The results indicate that the wind wall is linked to the well‐known high‐latitude wind convection pattern. This atmospheric circulation is significantly stronger during active geomagnetic conditions, where its dusk anticyclonic circulation cell is also enhanced, which results in the origin of the wind wall. The study also reveals the impacts of the wind wall on the vertical velocity and its consequences for the O(1S) green line emission on the lower thermosphere, as well as its influence on the atomic oxygen depletion at high latitudes, which is mainly a response to the complex high‐latitude wind convection pattern and its spatial and temporal variation.

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Section: The Wind Wall Impact On the Lower Thermosphere And Its Structuresupporting

confidence: 89%

“…

…”

mentioning

confidence: 99%

Observations and Modeling of Strong Thermospheric Winds at High Latitudes and Their Impact on the Lower Thermosphere

et al. 2021

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“…Such atypical increases (of up to 2000 K) have been observed in the night sector under disturbed conditions (see Schunk & Zhu 2008); a similar effect, however, is observed under quiet conditions. The electron density maximum is at approximately the same heights.…”

Section: High-latitude Solar Wind-magnetosphere-ionosphere Couplingsupporting

confidence: 72%

Geomagnetic response to solar and interplanetary disturbances

Sáiz

Cerrato

Cid

et al. 2013

J. Space Weather Space Clim.

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The space weather discipline involves different physical scenarios, which are characterised by very different physical conditions, ranging from the Sun to the terrestrial magnetosphere and ionosphere. Thanks to the great modelling effort made during the last years, a few Sun-to-ionosphere/thermosphere physics-based numerical codes have been developed. However, the success of the prediction is still far from achieving the desirable results and much more progress is needed. Some aspects involved in this progress concern both the technical progress (developing and validating tools to forecast, selecting the optimal parameters as inputs for the tools, improving accuracy in prediction with short lead time, etc.) and the scientific development, i.e., deeper understanding of the energy transfer process from the solar wind to the coupled magnetosphere-ionosphere-thermosphere system. The purpose of this paper is to collect the most relevant results related to these topics obtained during the COST Action ES0803. In an end-to-end forecasting scheme that uses an artificial neural network, we show that the forecasting results improve when gathering certain parameters, such as X-ray solar flares, Type II and/or Type IV radio emission and solar energetic particles enhancements as inputs for the algorithm. Regarding the solar wind-magnetosphere-ionosphere interaction topic, the geomagnetic responses at high and low latitudes are considered separately. At low latitudes, we present new insights into temporal evolution of the ring current, as seen by Burton's equation, in both main and recovery phases of the storm. At high latitudes, the PCC index appears as an achievement in modelling the coupling between the upper atmosphere and the solar wind, with a great potential for forecasting purposes. We also address the important role of small-scale field-aligned currents in Joule heating of the ionosphere even under non-disturbed conditions. Our scientific results in the framework of the COST Action ES0803 cover the topics from the short-term solar-activity evolution, i.e., space weather, to the long-term evolution of relevant solar/heliospheric/magnetospheric parameters, i.e., space climate. On the timescales of the Hale and Gleissberg cycles (22-and 88-year cycle respectively) we can highlight that the trend of solar, heliospheric and geomagnetic parameters shows the solar origin of the widely discussed increase in geomagnetic activity in the last century.

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“…Journal of Geophysical Research: Space Physics neutral density enhancements (approximately 10% during solar minimum), increased heating (approximately 10% neutral temperature increase), and neutral wind changes that depend on the ambient conditions (e.g., Ma & Schunk, 1997;Schunk & Zhu, 2008;Schunk et al, 2005).…”

Section: Plasma Density Enhancementsmentioning

confidence: 99%

Challenges to Understanding the Earth's Ionosphere and Thermosphere

Heelis¹,

Maute

2020

JGR Space Physics

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We discuss, in a limited way, some of the challenges to advancing our understanding and description of the coupled plasma and neutral gas that make up the ionosphere and thermosphere (I‐T). The I‐T is strongly influenced by wave motions of the neutral atmosphere from the lower atmosphere and is coupled to the magnetosphere, which supplies energetic particle precipitation and field‐aligned currents at high latitudes. The resulting plasma dynamics are associated with currents generated by solar heating and upward propagating waves, by heating from energetic particles and electromagnetic energy from the magnetosphere and by the closure of the field‐aligned currents applied at high latitudes. These three contributors to the current are functions of position, magnetic activity, and other variables that must be unraveled to understand how the I‐T responds to coupling from the surrounding regions of geospace. We have captured the challenges to this understanding in four major themes associated with coupling to the lower atmosphere, the generation and flow of currents within the I‐T region, the coupling to the magnetosphere, and the response of the I‐T region reflected in the neutral and plasma density changes. Addressing these challenges requires advances in observing the neutral density, composition, and velocity and simultaneous observations of the plasma density and motions as well as the particles and field‐aligned current describing the magnetospheric energy inputs. Additionally, our modeling capability must advance to include better descriptions of the processes affecting the I‐T region and incorporate coupling to below and above at smaller spatial and temporal scales.

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Response of the ionosphere–thermosphere system to magnetospheric processes

Cited by 5 publications

References 39 publications

Observations and Modeling of Strong Thermospheric Winds at High Latitudes and Their Impact on the Lower Thermosphere

Observations and Modeling of Strong Thermospheric Winds at High Latitudes and Their Impact on the Lower Thermosphere

Geomagnetic response to solar and interplanetary disturbances

Challenges to Understanding the Earth's Ionosphere and Thermosphere

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