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Physical Sciences and Mathematics Commons™
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- AGO ASI (1)
- Airglow patches (1)
- Auroral phenomena (1)
- DMSP satellites (1)
- Dayside polar cap (1)
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- Flow channels (1)
- IMF (1)
- Ionosphere (1)
- Ionosphere (Active experiments) (1)
- Ionosphere-magnetosphere interactions (1)
- Magnetospheric physics (1)
- Mesosphere (1)
- Midlatitude (1)
- Polar ionosphere (1)
- Radio science (Nonlinear phenomena) (1)
- Rayleigh-scatter lidar (1)
- Sudden stratospheric warming (1)
- Temperatures (1)
Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Analysis Of Close Conjunctions Between Dayside Polar Cap Airglow Patches And Flow Channels By All-Sky Imager And Dmsp, Boyi Wang, Yukitoshi Nishimura, Larry R. Lyons, Ying Zou, Herbert C. Carlson, Harald U. Frey, Stephen B. Mende
Analysis Of Close Conjunctions Between Dayside Polar Cap Airglow Patches And Flow Channels By All-Sky Imager And Dmsp, Boyi Wang, Yukitoshi Nishimura, Larry R. Lyons, Ying Zou, Herbert C. Carlson, Harald U. Frey, Stephen B. Mende
Faculty publications
Recent imager and radar observations in the nightside polar cap have shown evidence that polar cap patches are associated with localized flow channels. To understand how flow channels propagate from the dayside auroral oval into the polar cap, we use an all-sky imager in Antarctica and DMSP (F13, F15, F16, F17 and F18) to determine properties of density and flows associated with dayside polar cap patches. We identified 50 conjunction events during the southern winter seasons of 2007–2011. In a majority (45) of events, longitudinally narrow flow enhancements directed anti-sunward are found to be collocated with the patches, have velocities …
Connection Between The Midlatitude Mesosphere And Sudden Stratospheric Warmings As Measured By Rayleigh-Scatter Lidar, Leda Sox, Vincent B. Wickwar, Chad Fish, Joshua P. Herron
Connection Between The Midlatitude Mesosphere And Sudden Stratospheric Warmings As Measured By Rayleigh-Scatter Lidar, Leda Sox, Vincent B. Wickwar, Chad Fish, Joshua P. Herron
Faculty publications
While the mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are much more sparse. The Rayleigh-scatter lidar system, which operated at the Center for Atmospheric and Space Sciences on the campus of Utah State University (41.7°N, 111.8°W), collected a very dense set of observations, from 1993 to 2004, over a 45–90 km altitude range. This paper focuses on Rayleigh lidar temperatures derived during the six major SSW events that occurred during the 11 year period when the lidar was operating and aims to characterize the …
The Effect Of Negative-Energy Shells On The Schwarzschild Black Hole, Jeffrey Hazboun, Tevian Dray
The Effect Of Negative-Energy Shells On The Schwarzschild Black Hole, Jeffrey Hazboun, Tevian Dray
Faculty publications
We construct Penrose diagrams for Schwarzschild spacetimes joined by massless shells of matter, in the process correcting minor flaws in the similar diagrams drawn by Dray and ’t Hooft (Commun Math Phys 99:613–625, 1985), and confirming their result that such shells generate a horizon shift. We then consider shells with negative energy density, showing that the horizon shift in this case allows for travel between the heretofore causally separated exterior regions of the Schwarzschild geometry. These drawing techniques are then used to investigate the properties of successive shells, joining multiple Schwarzschild regions. Again, the presence of negative-energy shells leads to …
Phenomena Induced By Powerful Hf Pumping Towards Magnetic Zenith With A Frequency Near The F-Region Critical Frequency And The Third Electron Gyro Harmonic Frequency, N. F. Blagoveshchenskaya, Herbert C. Carlson, V. A. Kornienko, T. D. Borisova, M. T. Rietveld, T. K. Yeoman, A. Brekke
Phenomena Induced By Powerful Hf Pumping Towards Magnetic Zenith With A Frequency Near The F-Region Critical Frequency And The Third Electron Gyro Harmonic Frequency, N. F. Blagoveshchenskaya, Herbert C. Carlson, V. A. Kornienko, T. D. Borisova, M. T. Rietveld, T. K. Yeoman, A. Brekke
Faculty publications
Multi-instrument observational data from an experiment on 13 October 2006 at the EISCAT/HEATING facility at Tromsø, Norway are analysed. The experiment was carried out in the evening hours when the electron density in the F-region dropped, and the HF pump frequency fH was near and then above the critical frequency of the F2 layer. The distinctive feature of this experiment is that the pump frequency was just below the third electron gyro harmonic frequency, while both the HF pump beam and UHF radar beam were directed towards the magnetic zenith (MZ). The HF pump-induced phenomena were diagnosed with several instruments: …
On A New Process For Cusp Irregularity Production, Herbert C. Carlson, K. Oksavik, J. Moen
On A New Process For Cusp Irregularity Production, Herbert C. Carlson, K. Oksavik, J. Moen
Faculty publications
Two plasma instability mechanisms were thought until 2007 to dominate the formation of plasma irregularities in the F region high latitude and polar ionosphere; the gradient-drift driven instability, and the velocity-shear driven instability. The former mechanism was accepted as accounting for plasma structuring in polar cap patches, the latter for plasma structuring in polar cap sun aligned arcs. Recent work has established the need to replace this view of the past two decades with a new patch plasma structuring process (not a new mechanism), whereby shear-driven instabilities first rapidly structure the entering plasma, after which gradient drift instabilities build on …