Search Results - "Nicolls, M. J."

The phases and amplitudes of gravity waves propagating and dissipating in the thermosphere: Theory by Vadas, S. L., Nicolls, M. J.

“…We derive the high‐frequency, compressible, dissipative dispersion and polarization relations for linear acoustic‐gravity waves (GWs) and acoustic waves (AWs)…”
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Ionospheric and thermospheric variations associated with prompt penetration electric fields by Lu, G., Goncharenko, L., Nicolls, M. J., Maute, A., Coster, A., Paxton, L. J.

“…This paper presents a comprehensive modeling investigation of ionospheric and thermospheric variations during a prompt penetration electric field (PPEF) event…”
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Substorm triggering by new plasma intrusion: Incoherent-scatter radar observations by Lyons, L. R., Nishimura, Y., Shi, Y., Zou, S., Kim, H.-J., Angelopoulos, V., Heinselman, C., Nicolls, M. J., Fornacon, K.-H.

“…In the companion paper, we identified a repeatable sequence of events leading to substorm onset in THEMIS all‐sky imager observations: enhanced flows bring new…”
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Heating of the sunlit polar cap ionosphere by reflected photoelectrons by Varney, R. H., Solomon, S. C., Nicolls, M. J.

“…Photoelectrons escape from the ionosphere on sunlit polar cap field lines. In order for those field lines to carry zero current without significant heavy ion…”
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Nightside ionospheric electrodynamics associated with substorms: PFISR and THEMIS ASI observations by Zou, S., Lyons, L. R., Nicolls, M. J., Heinselman, C. J., Mende, S. B.

“…Observations from the newly available Poker Flat Incoherent Scatter Radar have been used to study the ionospheric electrodynamics during the substorm expansion…”
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Spatiotemporally resolved electrodynamic properties of a Sun-aligned arc over Resolute Bay by Perry, G. W., Dahlgren, H., Nicolls, M. J., Zettergren, M., St.-Maurice, J.-P., Semeter, J. L., Sundberg, T., Hosokawa, K., Shiokawa, K., Chen, S.

“…Common volume measurements by the Resolute Bay Incoherent Scatter Radar‐North (RISR‐N) and Optical Mesosphere and Thermosphere Imagers (OMTI) have been used to…”
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The phases and amplitudes of gravity waves propagating and dissipating in the thermosphere: Application to measurements over Alaska by Nicolls, M. J., Vadas, S. L., Meriwether, J. W., Conde, M. G., Hampton, D.

“…In a companion paper, we derived the high‐frequency, compressible, dissipative polarization relations for gravity waves (GWs) propagating in the thermosphere…”
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Observations of ionospheric heating during the passage of solar coronal hole fast streams by Sojka, J. J., McPherron, R. L., van Eyken, A. P., Nicolls, M. J., Heinselman, C. J., Kelly, J. D.

“…Using ionospheric temperature measurements made continuously by the Poker Flat Incoherent Scatter Radar (PFISR) and EISCAT Svalbard Radar (ESR) during the…”
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An investigation comparing ground‐based techniques that quantify auroral electron flux and conductance by Kaeppler, S. R., Hampton, D. L., Nicolls, M. J., Strømme, A., Solomon, S. C., Hecht, J. H., Conde, M. G.

“…We present three case studies that examine optical and radar methods for specifying precipitating auroral flux parameters and conductances. Three events were…”
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Anomalous ISR echoes preceding auroral breakup: Evidence for strong Langmuir turbulence by Akbari, H., Semeter, J. L., Dahlgren, H., Diaz, M., Zettergren, M., Strømme, A., Nicolls, M. J., Heinselman, C.

“…Experimental results obtained with the 449‐MHz Poker Flat Incoherent Scatter Radar (PFISR) show unusual features in both the ion line and plasma line…”
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Azimuthal flow bursts in the inner plasma sheet and possible connection with SAPS and plasma sheet earthward flow bursts by Lyons, L. R., Nishimura, Y., Gallardo-Lacourt, B., Nicolls, M. J., Chen, S., Hampton, D. L., Bristow, W. A., Ruohoniemi, J. M., Nishitani, N., Donovan, E. F., Angelopoulos, V.

“…We have combined radar observations and auroral images obtained during the Poker Flat Incoherent Scatter Radar Ion Neutral Observations in the Thermosphere…”
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Resolute Bay Incoherent Scatter Radar observations of plasma structures in the vicinity of polar holes by Makarevich, Roman A., Lamarche, L. J., Nicolls, M. J.

“…The Resolute Bay Incoherent Scatter Radar North (RISR‐N) data collected between January 2012 and June 2013 are employed to identify and analyze 14 events with…”
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Space-time variability of polar cap patches: Direct evidence for internal plasma structuring by Dahlgren, H., Perry, G. W., Semeter, J. L., St.-Maurice, J.-P., Hosokawa, K., Nicolls, M. J., Greffen, M., Shiokawa, K., Heinselman, C.

“…Coordinated observations of ionospheric variability near the geomagnetic pole using the Resolute Bay Incoherent Scatter Radar (RISR‐N), Super Dual Auroral…”
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Direct three-dimensional imaging of polar ionospheric structures with the Resolute Bay Incoherent Scatter Radar by Dahlgren, H., Semeter, J. L., Hosokawa, K., Nicolls, M. J., Butler, T. W., Johnsen, M. G., Shiokawa, K., Heinselman, C.

“…Ionospheric plasma density structures in the dayside F‐region of the polar cap are commonly occurring events, but adequate measurements of their formation and…”
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Poker Flat Incoherent Scatter Radar observations of anomalous electron heating in the E region by Makarevich, R. A., Koustov, A. V., Nicolls, M. J.

“…A comprehensive 2-year dataset collected with the Poker Flat Incoherent Scatter Radar (PFISR) located near Fairbanks, Alaska (MLAT = 65.4° N) is employed to…”
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Composite imaging of auroral forms and convective flows during a substorm cycle by Semeter, J., Butler, T. W., Zettergren, M., Heinselman, C. J., Nicolls, M. J.

“…Measurements obtained with the electronically steerable Poker Flat Incoherent Scatter Radar (PFISR) and collocated all‐sky camera were used to construct…”
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Magnetic aspect sensitivity of high-latitude E region irregularities measured by the RAX-2 CubeSat by Bahcivan, H., Cutler, J. W., Springmann, J. C., Doe, R., Nicolls, M. J.

“…The second Radio Aurora Explorer (RAX‐2) satellite has completed more than 30 conjunction experiments with the Advanced Modular Incoherent Scatter Radar chain…”
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Estimating E region density profiles from radio occultation measurements assisted by IDA4D by Nicolls, M. J., Rodrigues, F. S., Bust, G. S., Chau, J. L.

“…An alternative approach for estimating E region density profiles using radio occultation total electron content (ROTEC) measurements is presented. In this…”
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Identification of substorm onset location and preonset sequence using Reimei, THEMIS GBO, PFISR, and Geotail by Zou, S., Moldwin, M. B., Lyons, L. R., Nishimura, Y., Hirahara, M., Sakanoi, T., Asamura, K., Nicolls, M. J., Miyashita, Y., Mende, S. B., Heinselman, C. J.

“…We present state‐of‐the‐art multiple instrument observations of an isolated substorm on October 12, 2007. The auroral breakup was observed simultaneously by…”
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Observations in the E region ionosphere of kappa distribution functions associated with precipitating auroral electrons and discrete aurorae by Kaeppler, S. R., Nicolls, M. J., Strømme, A., Kletzing, C. A., Bounds, S. R.

“…Precipitating auroral electrons can produce discrete auroral arcs that contain signatures of the magnetospheric auroral source region. Differential number flux…”
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