Simultaneous observations of traveling convection vortices: Ionosphere‐thermosphere coupling

Kim, Hyomin; Lessard, M.; Jones, S. L.; Lynch, K. A.; Fernandes, P. A.; Aruliah, A. L.; Engebretson, M. J.; Moen, J.; Oksavik, K.; Yahnin, A. G.; Yeoman, T. K.

doi:10.1002/2017ja023904

Cited by 15 publications

(24 citation statements)

References 59 publications

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“…The peak enhancement of 300 K occurred at 200 km. This increase was of smaller magnitude than the radar data presented in Kim et al (), which showed a significant enhancement of 1000–3000 K between 200 and 300 km, and the PFISR data from Zou et al (), which showed an increase of 500–1000 K between 150 and 450 km. The enhancement of the electron temperature also appeared to last longer than the ion temperature enhancement in the PFISR observations.…”

Section: Discussioncontrasting

confidence: 60%

“…The peak enhancement of 300 K occurred at 200 km. This increase was of smaller magnitude than the radar data presented in Kim et al (2017), which showed a significant enhancement of 1000-3000 K between 200 and 300 km, and the PFISR data from Zou et al (2017), which showed an increase of 500-1000 K between 150…”

Section: Discussioncontrasting

confidence: 58%

“…The ion temperature displayed significant enhancements during the compression led TCV passage, with increases exceeding 1000 K at around 200 km altitude, consistent with observations shown by Zou et al (). Likewise, the European Incoherent Scatter Svalbard radar data presented by Kim et al () during a TCV event showed that the TCV passage led to an increase in ion temperature profiles between 1000 and 3000 K with two peaks at 150 and 300 km. In addition to the observations, the simulated ion temperature profile in Schunk, Zhu, and Sojka () had a single peak at 220 km with a 3000‐K increase during the event.…”

Section: Discussionmentioning

confidence: 85%

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Modeling Study of the Geospace System Response to the Solar Wind Dynamic Pressure Enhancement on 17 March 2015

et al. 2018

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The global magnetosphere‐ionosphere‐thermosphere system is intrinsically coupled and susceptible to external drivers such as solar wind dynamic pressure enhancements. In order to understand the large‐scale dynamic processes in the magnetosphere‐ionosphere‐thermosphere system due to the compression from the solar wind, the 17 March 2015 sudden commencement was studied in detail using global numerical models. This storm was one of the most geoeffective events of the solar cycle 24 with a minimum Dst of −222 nT. The Wind spacecraft recorded a 10‐nPa increment in the solar wind dynamic pressure, while the interplanetary magnetic field BZ became further northward. The University of Michigan Block‐Adaptive‐Tree Solar wind Roe‐type Upwind Scheme global magnetohydrodynamic code was utilized to study the generation and propagation of perturbations associated with the compression of the magnetosphere system. In addition, the high‐resolution electric potential and auroral power output from the magnetohydrodynamic model was used to drive the global ionosphere‐thermosphere model to investigate the ionosphere‐thermosphere system response to pressure enhancement. During the compression, the electric potentials and convection patterns in the polar ionosphere were significantly altered when the preliminary impulse and main impulse field‐aligned currents moved from dayside to nightside. As a result of enhanced frictional heating, plasma and neutral temperatures increased at the locations where the flow speeds were enhanced, whereas the electron density dropped at these locations. In particular, the region between the preliminary impulse and main impulse field‐aligned currents experienced the most significant heating with 1000‐K ion temperature increase and 20‐K neutral temperature increase within 2 min. Comparison of the simulation results with the Poker Flat Incoherent Scatter Radar observations showed reasonable agreements despite underestimated magnitudes.

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Section: Discussioncontrasting

confidence: 60%

Section: Discussioncontrasting

confidence: 58%

Section: Discussionmentioning

confidence: 85%

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Modeling Study of the Geospace System Response to the Solar Wind Dynamic Pressure Enhancement on 17 March 2015

et al. 2018

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“…Note that such rapid changes in the solar wind could trigger the travelling convection vortices in the ionosphere (e.g., Friis-Christensen et al, 1988;Kim et al, 2017). We start with the solar wind and IMF data, which are presented in Figures 2a-2c for the period 6:00-9:00 UT.…”

Section: Observationsmentioning

confidence: 99%

Simultaneous Rocket and Scintillation Observations of Plasma Irregularities Associated With a Reversed Flow Event in the Cusp Ionosphere

et al. 2019

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We present an overview of the ionospheric conditions during the launch of the Investigation of Cusp Irregularities 3 (ICI‐3) sounding rocket. ICI‐3 was launched from Ny‐Ålesund, Svalbard, at 7:21.31 UT on 3 December 2011. The objective of ICI‐3 was to intersect the reversed flow event (RFE), which is thought to be an important source for the rapid development of ionospheric irregularities in the cusp ionosphere. The interplanetary magnetic field was characterized by strongly negative Bz and weakly negative By. The EISCAT Svalbard radar (ESR) 32‐m beam was operating in a fast azimuth sweep mode between 180° (south) and 300° (northwest) at an elevation angle of 30°. The ESR observed a series of RFEs as westward flow channels that were opposed to the large‐scale eastward plasma flow in the prenoon sector. ICI‐3 intersected the first RFE in the ESR field of view and observed flow structures that were consistent with the ESR observations. Furthermore, ICI‐3 revealed finer‐scale flow structures inside the RFE. The high‐resolution electron density data show intense fluctuations at all scales throughout the RFE. The ionospheric pierce point of the GPS satellite PRN30, which was tracked at Hornsund, intersected the RFE at the same time. The GPS scintillation data show moderate phase scintillations and weak amplitude scintillations. A comparison of the power spectra reveals a good match between the ground‐based GPS carrier phase measurements and the spectral slope of the in situ electron density data in the lower frequency range. It demonstrates the possibility of modelling GPS scintillations from high‐resolution in situ electron density data.

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“…They include three major mechanisms. First, dynamic solar wind pressure events are a major source of traveling convection vortices (TCVs; Kim et al, 2017;Murr & Hughes, 2003;Shi et al, 2014;Sibeck et al, 1989). Second, Kelvin-Helmholtz waves (KHWs) can grow at the magnetopause velocity shear layer and are a very common phenomenon at the magnetosphere boundary particularly during northward IMF condition (Kavosi & Raeder, 2015;Lin et al, 2014).…”

Section: Observations Overviewmentioning

confidence: 99%

MMS/FEEPS Observations of Electron Microinjections Due to Kelvin‐Helmholtz Waves and Flux Transfer Events: A Case Study

et al. 2018

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The Energetic Particle Detector (EPD) suite onboard the Magnetospheric Multiscale (MMS) spacecraft observes dispersive and repetitive fluxes of high‐energy (50–400 keV) electrons within the Pc5 frequency band (2–8 MHz) in the dusk to midnight region of Earth's magnetotail. These microinjections are a new phenomenon in this region of the magnetosphere, presently poorly understood, but clearly a new signature that remotely senses large‐scale magnetospheric boundary dynamics. It is therefore important to understand their properties and driver mechanisms. Here we have combined global magnetohydrodynamic simulations and particle tracing results with the MMS EPD Fly's Eye Energetic Particle Spectrometer (FEEPS) observations to investigate possible origins and source regions of the electron microinjections. Our simulation results suggest that the electron microinjections, observed in the dusk to premidnight sector, are associated with Kelvin‐Helmholtz waves (KHWs) and flux transfer events (FTEs). Energetic electrons launched from a limited range of locations near the postnoon dusk magnetopause and at times when KHWs and FTEs pass by that region have drift paths that connect with MMS and thus create time‐dependent microinjection electron signatures. Test‐particle tracing results in the magnetohydrodynamic fields also support the field‐aligned nature of electron microinjections observed by MMS. Though identifying the mechanism by which KHWs and FTEs might periodically inject electrons is beyond the scope of this work, our study does identify these duskside magnetopause boundary phenomena as likely agents of microinjection origins.

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Simultaneous observations of traveling convection vortices: Ionosphere‐thermosphere coupling

Cited by 15 publications

References 59 publications

Modeling Study of the Geospace System Response to the Solar Wind Dynamic Pressure Enhancement on 17 March 2015

Modeling Study of the Geospace System Response to the Solar Wind Dynamic Pressure Enhancement on 17 March 2015

Simultaneous Rocket and Scintillation Observations of Plasma Irregularities Associated With a Reversed Flow Event in the Cusp Ionosphere

MMS/FEEPS Observations of Electron Microinjections Due to Kelvin‐Helmholtz Waves and Flux Transfer Events: A Case Study

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